NIAGARA RIVER ~R i~~ ~ N D 43O00' I sPORT COLBORNE eBUFFALO WOODLAWN PORT STANLEY STURGEON P IPORT BURWELL I FX V < >~ VIRVING -— (L-K — LONG PT IRK (LAKE UKE ST CLAIR DETROIT* WE ST FIELD O ERIU F ITE. AUX PINS A UR DETROIT RIVER /EQ i 1 42*00' A1SIN IGEON MONO STONY PT BAY PELEE POINT NNEAUT, MONROE P,4I>. PELEE PASSAGE T S A EAST SISTER IS.ULA RIV NO. BASS ISI. ES.ILLE RATTLESNAKE IS., ~PANESVE 0TOLEDO SO. BASS IS.;f BASS ISLANDS YMAUMEE SOUTH PASSAGE RIVER CATAWBA IS. ORIENTATION CHART L;REILEHEAD LEVELAND LAKE ERIE PMORAIN CLVAND SANDUSKY' SNDUVAHOGA RIV/ HURON ERMIL RIV. VERMLIONELYRIA 0 10 20 30 40 50 / BLACK STATUTE MILES RIV. o H 800' 82~00' 81o00' 80~00' 7900' Orientation chart.

GREAT LAKES RESEARCH INSTITUTE THE UNIVERSITY OF MICHIGAN EXPLORATION OF COLLATERAL DATA POTENTIALLY APPLICABLE TO GREAT LAKES HYDROGRAPHY AND FISHERIES Phase II Final Report U. S. Fish and Wildlife Service Contract No. 14-19-008-9381 Charles F. Powers Research Associate David L. Jones Research Associate Paul C. Mundinger Research Assistant John C. Ayers Project Director Ann Arbor, Michigan June 30, 1959

TABLE OF CONTENTS ge LIST OF FIGURES iv INTRODUCTION AND SUMMARY OF CONTENTS 1 SELECTION OF REPRESENTATIVE STATIONS 2 Availability and Accuracy of Data 2 Surface Circulation of Lake Erie 3 Description of data 5 Description of the circulation 8 Representative Stations for the West Basin.3 The data.3 Effect of intake location upon variability of data.4 Determination of representativeness.9 Representative Stations for the Central Basin'6 Representative Stations for the East Basin i2 Lake Erie Representative Stations: A Summary i3 A Representative Station for Lake Michigan i4 A TECHNIQUE FOR DETERMINATION OF WIND PATTERN OVER A LAKE 5 RAINFALL IN THE LAKE ERIE BASIN SINCE 1810 s1 PRE-1860 LAKE LEVELS OF LAKE ERIE 15 LAKE ERIE WATER CHEMISTRY SINCE 1854 46 The Metropolitan Population Index 49 INDICATIONS OF BIOLOGICAL CHANGE 50 SUMMARY OF MAJOR PAST EVENTS 52 CONCLUSION 52 LITERATURE CITED P5 APPENDIX I. VALUES BASED ON TOTAL ALKALINITY 51 Part 1, Station at Lorain, Ohio 61 Part 2, Station at Erie, Pennsylvania 11 APPENDIX II. LIMNOLOGICAL OBSERVATIONS 49 iii

LIST OF FIGURES No. Page Orientation chart. Frontispiece 1. Composite surface circulation, Lake Erie, under prevailing winds. 6 2. Dynamic topography of lake surface referred to the 20-decibar level; sutmer, 1929. 9 3. Surface turbidity, ppm; summer, 1929. 10 4. Surface total alkalinity, ppm; summer, 1929. 11 5. Average yearly range of turbidity vs. distance from shore and depth of intake, at Cleveland, Erie, Lorain, Fairport, and Avon Lake. 16 6. Average yearly range of total alkalinity vs. distance from shore and depth of intake, at Cleveland, Erie, Lorain, Fairport, and Avon Lake. 17 7. Average yearly ranges of total alkalinity before and after change of intake location at Conneaut. 18 8. Comparison of average total alkalinity ranges, Chandler (Bass Islands) and Lorain; 1938-40, 1943-45. 21 9. Temporal variation of turbidity at Rattlesnake Island and Lorain, with adjusted values for Lorain; 1941-45. 23 10. Adjustment curve, Lorain turbidity to Rattlesnake Island turbidity. 25 11. Isogon analysis. 37 12. Streamline analysis. 39 13. Isotach analysis. 40 14. Completed streamline-isotach analysis for 1300 EST, 23 October 42 1958. iv

INTRODUCTION AND SUMMARY OF CONTENTS The present work constitutes the Final Report on Phase II of U. S. Department of Interior, U. S. Fish and Wildlife Service, Contract 14-19-008-9381. Contract 14-19-008-9381 was laid out in three phases. These were: Phase I. To locate sources and repositories of limnological and meteorological data pertaining to the Great Lakes; to determine the types of data being taken by water plants and other lake-side installations; and to determine the periods of records. This phase was finished in June 1958 and reported by Powers et al. 1958. Phase II. To carry out a pilot study in which data from onshore and near shore sources were tried for compatibility with offshore cruise data; to determine which data sources were most nearly representative of open-lake conditions; to assess methodologies, instrumentations, and other aspects influencing the accuracy and/ or representativeness of the data. The present work is the Final Report on this phase. Phase III. To collect and report those data found to be of maximum usefulness. The assigned objectives of Phase II have been attained, and in several areas exceeded. The pilot study was carried out on Lake Erie, and consisted of actual application of data from onshore sources to the problem of obtaining a better understanding of the hydrography and aquatic environment. From the pilot study have come determinations of representative data sources for each of the three basins of the lake. From it has come a new and better concept of the current pattern of Lake Erie. And from it has come, in some cases indirectly, a series of data and techniques by which it is possible to reconstruct several aspects of the environment from the present well back into the nineteenth century. Among the latter, data and/or techniques for the reconstruction of wind patterns over the lake, rainfall, lake levels, and water chemistry are at hand and ready for application. Partial data are at hand (undoubtedly more can be obtained) for the reconstruction of the regimens of water temperature, air temperature, and weather conditions in and over Lake Erie for periods as long or longer than the extent of fishery records. Except for the partially complete items listed in the sentence above, these data and/or techniques are presented in this report. 1

A major portion of this report is given to the determination of "representative stations." These are water plants or other water-user installations where data are taken routinely and whose data are representative, in known degrees, of open-lake water, The concept of the representative station as a site or source of data where trends in the c.ondition of the aquatic environment can be conveniently and economically "watched" is not a new one, but it is believed that here for the first time are presented a series of realistically-appraised representative stations for a Great Lake. Once "calibrated" to open-lake conditions as is done here, these stations provide the means for continuous and continuing studies of environmental factors that bear upon fishery problems as well as upon the limnology and hydrography of the lakeo The authors extend their sincere thanks to Prof. D, M, Scott of the Department of Zoology, University of Western Ontario, London, Ontario, for permission to publish the station data of the Fisheries Research Laboratory of the University of Western Ontario. Located at Erieau on Point aux Pins, and receiving financial support from the Research Council of Ontario, this laboratory carried out valuable limnological investigations in west- and north-central Lake Erie in the years 1947-53o These data are given in Appendix II. They have been extremely valuable in our studies and we believe that others will welcome their publication as genuinely as we welcomed the chance to borrow them. SELECTION OF REPRESENTATIVE STATIONS One of the primary objectives of Phase II was the selection of shore stations (water filtration plants or other users of Lake Erie water) whose raw water analyses were indicative of conditions obtaining in at least a portion of Lake Erie. The lake is divided naturally into three basins: the west basin, extending to the eastern side of the Bass Islands; the central basin, lying between the Bass Islands on the west and Long Point on the east; and the east basin, between Long Point and Buffalo. A logical beginning to the selection of representative stations seemed to be on the basis of these geographical areas, that is, representative stations might be found for each of the basins. AVAILABILITY AND ACCURACY OF DATA Two separate categories of water quality data were needed: data obtained on the raw lake water by the filtration plants, and, for comparison with plant data, observations obtained by some other agency or agencies from the open lake at the same time0 The bulk of the information obtained by the plants consists of turbidity, total alkalinity, and bacterial counts, with water temperatures being observed at a few plants. No satisfactory method of utilizing bacteriological data being found, efforts were made to obtain open lake turbidity, alkalinity, and water temperature data. A search of the past history of the lake 2

revealed a paucity of open lake data, particularly of studies carried out at a particular location over a period of years. A limited body of data representative of open lake conditions, and usable in the selection of representative stations, was eventually assembled. These data are summarized in Table I. Filtration plants, and other sources of physical-chemical data on raw lake water which could be considered as containing possible representative stations have been tabulated in the Final Report, Phase I, of this project (Powers et al., 1958), along with their periods of record and the data obtained there. Observations upon the raw intake water are made at the filtration plants several times a week, Methodology varies among different plants; total alkalinity is always by titration, usually with methyl orange as the indicator, Turbidity is most generally obtained with the Hellige Turbidimeter, but the Jackson Candle and bottle standards are also in use, Visits were made by the investigators to most of the Lake Erie plants. In all cases the operators, superintendents, and chemists were impressive in their general attitudes, methods, and awareness of responsibility, It is believed that consistency of results may safely be assumed within individual plants; studies to date indicate, at worst, small systematic differences among plants which might be expected when one considers the inherent differences among methodologies and individual observers. Records for the filtration plants are maintained in reduced form, indicating for each month the average (and usually the maximum and minimum) value for any measured parameter, In Michigan and Ohio, these records are on file with the state departments of health. Data for Erie, Pennsylvania, and Woodlawn, New York, were obtained from the plants. Daily records are usually available for only a few years back, their further accumulation being burdensome and storage impractical. A lack of raw water data from Canadian filtration plants utilizing Lake Erie water restricted the search for representative stations almost entirely to the south shore of the lake. The selection of representative stations was a two-fold operation depending, first, upon a determination of the average surface current pattern (which would indicate those stations where offshore water came to shore) and, second, upon simultaneous shore station and open lake physical-chemical data that could be compared to give definitive assessments of the representativeness of stations apparently sampling water from offshore. Initial efforts, then, were directed at the determination of the average surface current pattern existing under the prevailing southwesterly wind, This pattern would be the one expected to Occur the majority of the time, SURFACE CIRCULATION OF LAKE ERIE Although complete synoptic coverage of Lake Erie has never been attempted, sufficient data from a number of sources now exist to permit the synthesis of a 3

TABLE I SUMMARY OF OPEN-LAKE PHYSICAL-CHEMICAL DATA USABLE IN THE SELECTION OF REPRESENTATIVE ONSHORE STATIONS Source Years and Region Applicable Data Buffalo Museum "Shearwater" 1928: east basin methyl orange, phenolphthalein, cruisesl 1929: east and central total alkalinity; turbidity; basins water temperature; wind speed and direction Do C. Chandler, University 1938-450 Bass Islands methyl orange, phenolphthalein, of Michigan2 total alkalinity; turbidity; water temperature " Do M. Scott, University of 1947-53: central basin methyl orange, phenolphthalein, Western Ontario, London3 total alkalinity; water temperature Uo S. Fish and Wildlife Ser- 1958: west basin, plus total alkalinity, turbidity, vice, Ann Arbor, Michigan4 drift bottle returns from silica, magnesium, sodium, water central and east basins temperature, wind speed and direction 11928 Data published (Parmenter, 1929). 1929 Unpublished data of C. J. Fish, Narragansett Marine Laboratory, University of Rhode Island. 2Data published in part: Chandler (1940, 1942, 1942-a, 1944); Chandler and Weeks (1945). 3Data published here (Appendix II)o 4Data published in part: U. S. Fish and Wildlife Service Cruise Reports (1958).

composite pattern of surface circulation. The pattern as derived appears to be generally representative of the surface currents existent under the normal regimen of prevailing southwest winds9 The data sources utilized in the present synthesis, together with the specific portions of the lake which they represent, are as follows: 1. West end: Ayers (unpublished), Harrington (1894), Millar (1952), Olson (1951), U. S. Fish and Wildlife Service (1958), Verber (1955), Wright and Tidd (1955). 2. Bass Islands to Dunkirk: Buffalo Museum 1929 cruises (unpublished), Harrington (1894), U. S. Fish and Wildlife Service (1958). 3. Dunkirk to Buffalo: Harrington (1894), Parmenter (1929), U. S. Fish and Wildlife Service (1958), Fall (1910), McLaughlin (1911). Of the Buffalo Museum 1929 cruises, Cruise 2, made in June 1929, is the only one applicable to the synthesis of a current pattern. Between the Bass Islands and Dunkirk most of the stations were occupied under winds from westerly quarters; exceptions were stations 43-46 (wind S-zero to calm) and stations 3237 (wind calm to SE-2). Between Dunkirk and Buffalo winds were from easterly, quarters, hence data of Cruise 2 from that area have not been utilized here. Data from the several remaining cruises made by the Buffalo Museum in the summer of 1929 were not suitable for incorporation into an analysis of the circulation, due to the variable winds encountered during each cruise. Observations of temperature from Cruise 2 have been used in the computation of dynamic heights over that portion of the lake between Cleveland and Dunkirk. Although temperatures at each station were obtained at only surface, ten meters, and bottom, the lack of thermal stratification in early June lends validity to interpretations of vertical temperature structure based upon these relatively few data,. A reference level at only twenty meters was required by the shallowness of the lake, and the assumption of no motion at this depth is probably not altogether realistic. However, the completed dynamic topography appears reasonable and is consistent with other parameters. Plots of turbidity and total alkalinity, as observed during Cruise 2, have been used as supplementary evidences of circulation patterns. Drift bottle returns from releases made by the U. S. Fish and Wildlife Service during 1958 and by Harrington in 1892 and 1893 have been used extensively in checking the computed current pattern between Cleveland and Dunkirk, and in deduction of the circulation pattern in the western and eastern ends of the lake where no dynamic calculations were possible. Other sources to which reference has already been made, were consulted in the analysis of the west basin circulation. The final current pattern as synthesized from all data is given in Fig. 1. Description of Data.-The usual description of data is not feasible here, since the results of numerous workers have been used. For the most part, neces5

83~00' 8200' 8100' 80000' 7 90 00' 4300' STATUTE MILES La\~~~~~~~ I I II I_4' Fig. 1. Composite surface circulation, Lake Erie, under prevailing winds.

sary description is incorporated into the presentation of the deduced composite circulation. However, returns of the Fish and Wildlife Service (hereafter referred to as FWS) drift bottle releases of May and August, 1958, merit special consideration, for certain features of their distributions have particular significance. In May, bottles released at stations northwest and north of Pelee Island stranded in three regions: on the west side of Pelee Point; between Port Burwell and the tip of Long Point; and on the south shore between Irving, N. Y. and Buffalo. In addition, one bottle was recovered on Grand Island in the Niagara River. Bottles released in the same longitude, but south of the north end of Pelee Island, were recovered on the south shore between Catawba Island and Dunkirk, New York, with a few stranding in the Bass Islands. None of these bottles were recovered from the north shore. A further feature of the south shore recoveries was the concentration of returns between Catawba Islandand Fairport, and the virtual absence of returns from Fairport to the Pennsylvania-New York state line. Only one bottle was found (at Erie, Pa.) in this otherwise barren region, although returns were obtained from the New York shore farthest east. Special note should be taken of the fact that bottles released north and south of Pelee Island remained completely separated, except along the New York shoreline where bottles from both areas of release were recovered. In August, the pattern of returns was quite similar to that of May. The differential north shore-south shore pattern was still present, the primary difference being that the line of demarcation between north-shore-stranding stations and south-shore-stranding stations had shifted to the south. The line now lay slightly south of the southern end of Pelee Island. Bottles from north shore stations were again found at Pelee Point, between Port Burwell and the tip of Long Point, and on the south shore between the Pennsylvania-New York boundary and Buffalo. In addition, bottles were recovered from Point aux Pins, Grand Island, Port Colborne, and between Pelee Point and Point aux Pins. Bottles from all remaining stations in the Bass Islands longitude beached on the south shore, predominantly between Fairport and Conneaut, Absence of returns from a large portion of the south shore, the region between Conneaut and the Pennsylvania-New York line, was again in evidence. Again, only a single bottle (recovered at Erie, Pa.) appeared in this otherwise recoveryless stretch of shoreline. Bottles from two of the south shore stations progressed beyond Conneaut: those from one station off Marblehead beached at Erie and at Sturgeon Point, N. Y.; those from a station just west of Catawba Island beached at the PennsylvaniaNew York line, near Port Colborne, Ontario, and on Grand Island. Recoveries from drift bottle releases made by Harrington in 1892-93 coincide well with those of the 1958 FWS releases. With the exception of one bottle that stranded on the shore of Pigeon Bay (in the west basin), none of his bottles released in the Bass Islands region south of Pelee Island beached on the north shore~ Also, the south shore hiatus observed in the FWS returns is evident: only one return was obtained from the shore between Conneaut and Westfield. 7

Description of the Circulation.-Investigations in the west basin of Lake Erie have indicated the circulation to be complex and variable, In general, under the normally prevailing southwesterly winds, the effluent of the Detroit River (the major source of inflow into Lake Erie) swings through the basin in a counterclockwise loop. This water, identifiable by its comparatively low turbidity, alkalinity, and hardness is commonly observed passing eastward through Pelee Passage. South of Pelee Island increased turbidity, alkalinity, and hardness indicate the presence of admixed quantities of water from the Maumee River and from smaller streams, principally the Huron, Raisin, and Portage rivers. This mixed water ordinarily passes east through the Bass Islands, The boundary separating the unmodified Detroit River water from the mixed water fluctuates in geographic location, being strongly and rapidly influenced by changes in direction ~f wind. As indicated by the dynamic heights computed from the Buffalo Museum Cruise 2 (Fig, 2), the outflow from Pelee Passage moves to the northeast toward Point aux Pins and along the lakeward side of a tentative counterclockwise eddy lying in the embayment between Pelee Point and Point aux Pins. This eddy is supported by two FWS bottles, released in August 1958 just southwest of Pelee Point, which stranded halfway between Pelee Point and Point aux Pins, and by the very existence of the two points themselves which could be both built and maintained by such an eddy circulation. Three bottles released near mid-lake by Harrington were recovered on the beach west of Point aux Pins; they likewise point to the existence of this eddy. The main line of current flow continues northeast past Point aux Pins, toward Port Burwell, and passes along the outside of a counterclockwise eddy lying in the embayment between Point aux Pins and Port Burwell. This eddy, also considered tentative, is confirmed by two FWS bottles released in August 1958 just southwest of North Bass Island and which stranded near Port Bruce" also by two of Harrington's bottles: one from just south of Pelee Point which stranded west of Port Stanley, and one released south-southwest of Port Stanley near mid-lake and recovered at Point aux Pins. Southeast of Port Burwell the main current impinges on shore in an area marked by concentrated bottle returns from FWS "north shore"' stations. This impingement is indicated by the tongue-like extension of the dynamic height contour of 20.011 (Fig. 2), by the area of < 3 ppm turbidity extending northeast to this point (Fig, 3), and by the 102 ppm contour of total alkalinity (Fig. 4). It is also the site of beaching of two of Harrington's bottles which were released north of mid-lake off Point aux Pins. After impinging on Long Point, the current is indicated by the dynamic computations as turning southwest away from shore, to mid-lake., thence northeast again to Long Point at an area several miles southeast of the initial impingement. The return of the current to this region is substantiated by another concentration of FWS bottles released near mid-lake southwest of Long Point; by the northeast extension of the 3 and 4 ppm contours of turbidity extending from midlake (Fig. 3); and by the extension shoreward of a > 102 ppm area of total alkalinity located in mid-lake (Fig. 4). 8

83000' 82:00' 81,00' 80000' 79000' 4300'.0074 I I STATUTE MILES 0 10 20 30 40 iO Fig. 2. Dynamic topography of lake surface referred to the 20-decibar level; summer.,129

83w00 82*00' 81*00' 00o00Q 7900' 5 5 2 92'~~~~~~~~~~~~~~~~400' 02 STATUTE MILES 0 10 20 30 40 50 Fig. 5. Surface turbidity, ppm; summer, 1929.

83~00' 82~ 00' 81000' 80~00' 79~00' I I I 43000' H < I- o _ _ < Y 10 20 30 40 50 Fig. 4. Surface total alkalinity, ppm; summer, 1929.

After its second impingement on Long Point, the current appears to flow southeast along the Point before once again swinging away from shore, southwestward, to cross the lake. In the region off Ashtabula it encounters an eastward flow along the south shore. The southwestward recurving of the 3 and 4 ppm contours of turbidity (Fig. 3) support the dynamics in indicating this southwest flow. The southern alongshore current appears to have originated partly as the outflow from the west basin through the Bass Islands, and partly as a southeast offshoot of the main current through Pelee Passage. The dynamic heights (Fig. 2) indicate a southeast current originating south of Point aux Pins, and such a flow is also suggested by the southeast curving of the contours of turbidity (Fig. 3) and total alkalinity (Fig, 4) in that region. Evidence for the alongshore current emanating from the island region is obtained from FWS drift bottle returns from releases at "south shore" stations, where beaching occurred all along shore from Catawba Island to Conneaut; from the lobate gradient of turbidity, with values increasing toward the west, situated off Lorain and Cleveland (Fig. 3), and by the 98 ppm contour of total alkalinity leading from the Bass Islands and beaching near Lorain (Fig. 4). Numerous bottles released by Harrington also were recovered along the south shore, particularly between Cleveland and Conneaut. The eastward current along the south shore near Erie, Pennsylvania, appears to have the effect of holding offshore the current arriving from the north side of the lake. The dynamic height contours of 20.011, 20.090, and 20.070 dynamic meters extend southwest from Long Point, recurve to parallel the axis of the lake, and then come to shore east of Erie (Fig. 2). The suggestion that this current remains offshore between Conneaut and the vicinity of the Pennsylvania-New York line is substantiated by the lack of drift bottle returns from this section of shore in the results of both Harrington and the FWS. It is also suggested by the shape of the 98 ppm contour of total alkalinity (Fig. 4), and by the 5 ppm contour of turbidity (Fig. 3) which remains offshore to the vicinity of Erie, where it encounters an east-west gradient with isopleths beaching east of Presque Isle, East of Long Point and Erie the circulation pattern is somewhat conjectural. Data obtained in this region by the Buffalo Museum during the summer of 1928 (Parmenter, 1929) indicate an eastward flow extending from the central axis of the lake to the south shore, continuous to the outlet at the Niagara River. Fall (1910) and McLaughlin (1911) also show the eastern parts of such a flow. Drift bottle returns of Harrington and FWS support the existence of the eastward flow to the outlet. The data also suggest that easterly winds can bring about a reversal of this flow, but the frequency of such a reversal and its effect on the circulation of the central basin cannot be assessed from the information available In the embayment to the east of Lon g Point there is evidence of a counterclockwise eddy, This evidence is furnished by several Harrington's drift bottles which apparently followed courses indicative of a counter (westward) flow along the Canadian shore between Port Colborne and Long Point. Also, two FWS 12

bottles released in August were recovered at Port Colborne. The northward recurving of the eastward portion of the turbidity gradient located south and southeast of Long Point (Fig. 5), as well as the curvature of the 98 and 94 ppm contours of total alkalinity extending eastward from Long Point (Fig, 4) are suggestive of eddy motion in this area. REPRESENTATIVE STATIONS FOR THE WEST BASIN It might be expected that a station representative of open lake conditions in the west basin would be one of those located on the shores of this basin, that is, the filtration plants at Monroe, Toledo, or Port Clinton. None of these plants were usable, however, because each reflects the conditions of a localized water source and not the mixed product of the several sources contributing to the west basin, As has been pointed out, the circulation in this basin is complex and variable, Depending upon the wind, Monroe's intake off Stony Point may sample, predominantly, either Detroit River or Maumee River water and may at times be largely affected by the effluent of the River Raisin which enters the lake at Monroe south of the intake, The Toledo intake, being located near the mouth of the Maumee River, samples proportionately large amounts of water from this source. The Port Clinton intake is located just off the mouth of the Portage River and largely reflects conditions of the river water rather than those of the lake, Knowledge of physical-chemical conditions existing in the Maumee and Portage rivers was obtained from data of the Lake Erie Pollution Survey Supplement (State of Ohio, 1953). Since the generalized circulation pattern shows the presence of an eastward flow along the south shore of the lake and indicates that this flow might be the mixed effluent from the west basin, it appeared reasonable to continue the search for a station representative of the west basin by using data from filtration plants located on the south shore to the east of the Bass Islands. Such south shore plants are Sandusky, Huron, Vermilion, Elyria, Lorain, Avon Lake, Cleveland, Fairport, Painesville, Ashtabula, and Conneaut. The Data. — Data obtained by D. C. Chandler in the Bass Islands region were considered to be adequately representative of water conditions in the west basin. These data were obtained between September 1938 and December 1945. A number of parameters were observed, but for purposes of the present investigation turbidity and total alkalinity were the most applicable, they being parameters consistently measured by the filtration plants. Periods and locations of these observations, as obtained by Chandler, are as follows: (1) Total alkalinity: September 1938 to October 1940, at a single station just off the west side of Rattlesnake Island; January 1943 to December 1945, at four stations located in a north-south direction: one just northeast of East Sister Island, one just west of North Bass Island} one at Rattlesnake Island (identical with the one used in the l938-40 series), and one in South Passage between Catawba Island and South Bass Island, 15

(2) Turbidity: January 1941 to December 1945, at the Rattlesnake Island station. (Some previous data also exist, but are not as nearly complete as the 1941-45 data.) Measurements of total alkalinity and turbidity obtained by Lake Erie filtration plants were available for the same time intervals as those during which Chandler's investigations were conducted. Since the plant data were monthly averages, Chandler's data were likewise reduced: all observations for a given calendar month being averaged to obtain a single monthly mean. Direct comparisons between the onshore and open lake observations could then be attempted. It should be pointed out that Chandler's observations of total alkalinity were obtained once a week, on the average, so that they probably do not present as realistic a mean value as do those from the plants which are based on 20-30 days' observations. On the other hand, the turbidity observations of Chandler were made almost daily, except in mid-winter when fewer data were obtained. Effect of Intake Location Upon Variability of Data. —Initial examination of the alkalinity data of several of the plants and comparison of these data to those the Ohio Pollution Survey obtained in various bays, harbors, and rivers made possible the immediate elimination of the following plants: Sandusky - water partially from Sandusky Bay Huron - water partially from Sandusky Bay Fairport - local industrial pollution Painesville - local industrial pollution Ashtabula - raw water alkalinity not measured While these studies were going on it was noted that there was an apparent relationship between intake location and variability of observed alkalinity and turbidity. The intake location studies substantiated the elimination of the above plants and also suggested the further elimination of Vermilion, Elyria, Avon Lake, and Conneauto To examine the effects of intake location, five plants were chosen whose intakes were located at different distances from shore. The plants and their intake locations are: Intake Distance Intake Depth from Shore (ft) (ft) Cleveland (Division Plant), Ohio 21,120 36 Erie, Pennsylvania 6,200 22 Lorain, Ohio 2,000 13 Avon Lake, Ohio 1,400 12 Fairport, Ohio 1,000 12 14

For these plants, data over the twelve year period 1940-1951 inclusive were arbitrarily chosen as representing average conditions. For each year's data at each plant the lowest monthly average of both turbidity and alkalinity was subtracted from the highest monthly average to obtain the average range for the year. The twelve annual ranges for each plant were then combined to give a twelve years' overall average range for each parameter. These average values were then entered upon graphs in which ranges of turbidity and alkalinity were plotted against distance of intake from shore and against depth of intake. The turbidity results were quite clear-cut (Fig. 5). Variabilities were about the same at Cleveland and Erie, with Erie showing slightly less variability. This is apparently due to the geographic position of the Cleveland intakes. They are situated where they may be reached by waters of both the western and central basins. The Cleveland variability is most probably caused by alternate sampling of western and central basin waters as shifts in wind direction bring one or the other of these two water types over the intakes. Variability increased sharply at Lorain where the intake is 2,000 feet out, and was still more pronounced at Avon Lake and Fairport whose intakes are 1,400 and 1,000 feet from shore respectively. Variation of total alkalinity with intake location (Fig. 6) is as clearly defined as was that of turbidity, and the curve is approximately like that for turbidity. Cleveland again has a greater range of variability than does Erie (and the same reason apparently applied), Lorain has a slightly higher variability, than does Fairport but the difference, half a part per million, is probably not significant. The curves relating variability to intake depth approximated the distancefrom-shore curves and both showed lessened variability with greater depth and with greater distance from shore. This is to be expected since distance from shore and depth of intake are not mutually-independent variableso Further evidence of the effect of intake location has come from the data of the Conneaut plant, whose intake was moved further but in 1933. The previous location has not been ascertainable, but it was inshore of the present site. Variability of total alkalinity before and after the change is depicted in Fig. 7O The bars are yearly ranges of alkalinity, based on monthly averages, for the years 1923 through 1942. The stabilizing effect of the intake change is evident. The greatest range occurring after 1933 (26 ppm in 1940) is equal to the least range that occurred in the years prior to the change (26 ppm in 1928). It seems likely that, of the two variables, distance from shore is the more important. Best correlation of alkalinity and turbidity data from Lorain with those of Chandler from -te Bass Islands (discussed later) was obtained in years when rainfall and runoff were normal or below normal, with correlation becoming less good in wet years. If depth of intake were the more important, the reverse situation might have been expected, i.e., better correlation in wet years when lake level might be rising and depths to the intakes increasing But during 1938-40, when the best correlation was obtained, the lake level was significantly 15

26 36 CLEVELAND (DIVISION) 24 34 22 -.32 CLEVELAN4D (DIViSION) 2030 "oI 1-28 _RANGE VS. INTAKE DEPTH w w IL z 16 26w -------- RANGE VS. DISTANCE OF L~;I INTAKE FROM SHORE z 0 14..24 0 W X 12 22 a ERIE w r CY,\ X 10.. 20 t Z Il 081 w z 4. 6 1$ XERIE 4 14 LRIN AVON 2 12 FAIRPORT LAKE LORAIN FAIRPORT LAKE 20 30 40 do 60 70 so 90 i AVERAGE YEARLY RANGE OF TURBIDITY, PPM. Fig. 5. Average yearly range of turbidity vs. distance from shore and depth of intake, at Cleveland, Erie, Lorain, Fairport, and Avon Lake.

26 36 CLEVELAND (DIVISION) 24. 34 22- -32 CLEVELAND (DIVISION) 20-30 is tL828, RANGE VS. INTAKE DEPTH t6 2' ------- -— RANGE VS. DISTANCE OF Z INTAKE FROM SHORE IL =,14.24 zr z o I'12.22. ERIE o,, 10. 20 Y z z 8. 8.18 0 zg 6sC16 X ERIE 4.14 \.LORAIN 2 12'' FAIRPORT. ".-...R. __LORAIN _ AVON LAKE FAIRPORTx 0o 6 2'1 1t AVERAGE YEARLY RANGE OF TOTAL ALKALINITY, P. RM. Fig. 6. Average yearly range of total alkalinity vs. distance from shore and depth of intake, at Cleveland, Erie, Lorain, Fairport, and Avon Lake. 17

6 z C3 Ci 4 0 I4 W 4J 0 0 4 at I- ~~~~~~~~~~w LL H 0 Z 0 4~~~~~~~~~~~~~~ 4~~~~~~~~~~~~~~ WU'U W~~~~~~~~~~~ 49 1923 1924 1925 1926 9927 1928 1929 9930 9931 1932 1933 1934 9935 9936 1937 1938 1939 99409949 9942 Fig. 7. Average yearly ranges of total alkalinity before and after change of intake location at Conneaut.

lower than in 1943-45 when correlation was less satisfactory~ There appears to be a critical distance, about 2,000-4,000 feet offshore, at which a marked change in variability of parameters occurs. At greater intake lengths, fluctuations are small. At less than this critical range, decreasing distance from shore is accompanied by increasing fluctuation. It appears, also, that increased runoff from tributary streams during wet years serves to increase alongshore variation in the several parameters, and those plants with intakes farthest from shore are least affected. During dry years the plants with short intakes reflect in the decreased variability of their data the decreased alongshore fluctuations that accompany decreased runoffsThe above must not be taken to imply that depth of intake is unimportant. For drinking-water purposes, it is desirable that the intake be, if possible, below the normal depth of the thermoclineo The scanty data presently available (not discussed in this report) indicate that water of materially better quality is to be had from beneath the thermocline, The reason for this appears to be that the density stratification accompanying the thermocline confines to the epilimnion much of the pollution introduced along shore, Height of intake above bottom appears to be an independent secondary factor that is imposed upon the effect of distance from shore. The two intakes at Cleveland are located the same distance from shore, but that for the Baldwin plant is higher off the bottom than is that of the Division plant. The raw water of the Baldwin plant consistently runs 7 to 17 ppm lower in turbidity and 1 to 2 ppm lower in alkalinity than does that of the Division plant (see Table TI), The reason for the differences appears to be that sediments resuspended from the lake bottom by winds or currents have freer access to the lower intake of the Division plant. Determination of Representativeness.-On the basis of both current pattern and intake location Lorain appeared to possess the greatest likelihood of being a representative station for the west basin, with Cleveland a less strong possibility, Time graphs were constructed on which monthly average total alkalinities and turbidities for the plants at Lorain, Vermilion. Avon Lake, Cleveland. Conneaut, and Erie were plotted against time. Chandler's Bass Islands data were also entered on this graph~ In the case of total alkalinity) good visual agreement was obtained between Lorain and Chandler, Conneaut and Chandler, Vermilion and Chandler, and Cleveland and Chandler, both as to trends in alkalinity fluctuations and absolute values. Of these, best agreement existed between Lcrain and Chandler and Conneaut and Chandler for the years 1938-40o Significant coefficients of correlation were obtained for these latter pairs. For the wet years 1943-45 (Chandler's Bass Islands data for 1941-42 are not available) agreement between these location pairs 19

TABLE II Division Baldwin Average of Stations 47 and 48 Division Baldwin Surface Bottom Surface and Bottom Alkalinity June 93 92 97 93 95 July 93 92 96.5 94 95 Aug. 95 93 955 9 Sept. 96 94 97.5 98.5 98 Turbidity June 25 8 12 16 14 July 13 6 4 8 6 Aug. 13 6 7 8 7.5 Sept.* 16 7 10 10 10 *Station 47 only. was less good, and significant coefficients of correlation were no longer attainable. Visual inspection for these latter years indicated that, of all plants, best agreement existed between Lorain and Chandler. A time graph was next constructed on which were plotted the monthly maximum and minimum values for Lorain and for Chandler. Connecting thesepoints resulted in two "bands" expressing the ranges of total alkalinity observed at the two locations. Overlapping of the two bands occurred in 51 months. Discrepancies in this plot prompted one further comparison. The average ranges of total alkalinity variation for the whole period of observation were computed for both Lorain and Chandler. This gave a single average range for each of the locations. The average range for each location was entered upon a time graph by centering it upon the monthly mean of each month. The two bands thus produced overlapped in 55 of the total 62 months (Fig. 8). This is taken as indicating that average conditions observed at Lorain reflect average conditions in the Bass Islands. Before taking up turbidity, a discussion of the good agreement of onshore - offshore alkalinities during 1938-40 versus the poorer agreement during 1943-45 is in order. The various factors considered as possible agents in bringing about the observed disparity are: errors in sampling and determination of alkalinities; changes of intake location at filtration plants between 1938 and 1945; changes in personnel at filtration plants; prevailing winds; alkalinity of tributary streams; and runoff into the lake. These factors will be considered separately, (1) Errors in sampling and determination of alkalinities. There is no basis for suspecting operational error, either at the filtration plants or in Chandler s observations, 20

1938-1940: DRY' YEARS:!105 I.a: 95 z < 85.-J ~-75 SEPT'38 JAN.'39 JAN.'40 OCT.'40 1943-1945: "WET YEARS > II it a. 1-05 z J -J 95 0 t- 85 75 I I I I I I A FEB'43 JAN.'44 JAN. 45 DEC. 45 Fig. 8. Comparison of average total alkalinity ranges, Chandler (Bass Islands) and Lorain; 1938-40, 1943-45.

(2) Changes of intake location. None of the plants under consideration changed the location of their intakes during 1938-45. (3) Changes of personnel at filtration plants. No changes occurred. (4) Prevailing winds. It was thought that significant changes in direction of prevailing winds during 1943-45, as compared to 1938-40, might have resulted in alterations of average current patterns which in turn would have altered the distribution of total alkalinity. As a check on this hypothesis, average monthly wind directions and speeds were obtained for Cleveland from the United States Weather Review. Vector plots were constructed in order to obtain the average wind direction and speed for the two periods under consideration. Although monthly deviations from the average were present, no long-time differences occurred, the average directions being essentially the same for the two periods. (5) Alkalinity of tributary streams. A number of Ohio streams tributary to Lake Erie were subjected to chemical analysis during 1950-52 as a part of the Lake Erie pollution survey conducted by the State of Ohio Water Resources Commission (State of Ohio, 1953)o No direct or consistent relationship between actual alkalinity values of the streams and those observed at Lorain are apparent, other than the regular seasonal variations generally exhibited by total alkalinity in natural bodies of water. (6) Runoff. This was the only factor in which there was a significant difference between 1938-40 and 1943-45. Among the gauged streams entering this portion of Lake Erie the Maumee, Sandusky, Cuyahoga, and Ashtabula were selected as indicators of runoff conditions. Using volume-of-flow data from the Uo S. Geological Survey Water Supply Papers, the combined annual runoff of these four rivers was obtained by totaling their mean monthly discharges for each of the years 1938-45. Runoff during 1943-45 was about 50% higher than in 1938-40. The increase was general over the entire west-basin region; it included the Detroit River as well as the above rivers, It is thus established that the years of poorer agreement between onshore and offshore alkalinities were years of materially increased runoff. Turbidity observations obtained by Chandler at Rattlesnake Island between 1941 and 1945 were in generally good agreement with those recorded at Lorain in the same years (Fig. 9). At both locations there are two "pulses" of turbidity per year, one in the spring and the other in the fall. The spring pulse contains higher turbidity values than does the fallo The pulses occurred at Lorain and Rattlesnake Island at about the same time, except in the falls of 1941 and 1942, Comparison of these twice-yearly pulses with the runoff of the Black River* at *The Black River was not gauged; monthly discharge figures for it were obtained from the averages of the Sandusky and Cuyahoga Rivers, the nearest gauged streams. The monthly discharge rates per square mile of watershed for these two rivers were averaged and the average per square mile multiplied by the watershed area of the Black. 22

I10, 100 A TURBIDITY AT RATTLESNAKE IS. /i -..TURBIDITY AT LORAIN 90o 1, --- - ADJUSTED TURBIDITY AT LORAIN I I.8o i I >.'7o_ I I n60_ C,~~~~~~~~~~~~~~~~~~~f o:50_ LU J ~~~~~~~>, ~~~~~~~~~~~~~~~~~~~~I >'40 I - r ~~~~~~~~r,', 230 /','.-', I, I \'I 10 /I ~.1:''%", JAN'SEP' JAN MAY SEPT JAN M:AY'94 1941 1942 14 250 %~~~~~~~~~~~~~~~~~~~~~~~ w~~~~~~~~ z A A 0.* >, I. I,,,I / \\~ 0f 1943 SEPT JAN MAY 19 4 4 SEPT JAN MAY 1945 SP ~ [ MY [ S r'I ] I i I [ Ir,, I,,,' I 1943 SEPT ~~~~JAN MAY 19 4 SEPT JAN MAY 194 5 SP E W~~~~~~~~~~~~l ^ Fig~~~~. 9. Tepoa vaito/ftrbdt/tRtlsnk sada ~$0 _ ~-`~ ~ "' — IC-~~. \i,'', ~.i: // z~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.. Lorain, with adjusted values for Lorain; 1941-45. 25

Lorain reveals that the spring pulse occurs at the time of the late-winter-earlyspring melt-off. The fall pulses occur during periods of greatly reduced river flows, The spring pulse is probably the result of suspended materials carried into the lake by runoff waters and also, to a less degree, of the spring plankton bloom which regularly occurs at this period. The fall pulse is probably due to bottom sediments suspended by winds and to the fall plankton bloom; the decreased runoff would contribute very little suspended material at this time, In view of the favorable agreement in trends, and of the relatively few ppm difference in actual values, between the turbidity observations at Lorain and Rattlesnake Island the possibility of applying corrections to bring the two in even better agreement was considered. A scatter diagram was made in which average monthly values at Lorain were plotted against the difference in monthly means of Chandler and Lorain. This gave a curvilinear arrangement of points to which a curve was fitted by eye (Fig. 10). The curvature and scatter of points increased with decreasing turbidity values. A series of adjustment factors were derived from the slope of the curve by breaking the curve into a series of segments, taking each segment to be a straight line, and determining the slope of the segment. Adjustment factors were actually computed only for that portion of the curve lying above Lorain turbidities of 20 ppm. Turbidities below this value exhibited such a large scatter as to give unrealistic adjustment factors; an arbitrary factor of 1.20 has been used for this range. It appears to perform satisfactorily. Adjustment factors and the turbidity ranges to which they apply are: Lorain Turbidity Adjustment ppm Factor 0-20 X 1,20 = Rattlesnake Island turbidity 21-25 1.10 26-30 0.90 31-355 0.8 36-40 0o80 41-45 0 o75 46-50 0o 65 51-80 0.6o 81-100 0.55 101- 0.50 The adjusted values of Lorain's turbidities are shown in Fig. 10. It appears reasonable to conclude, on the basis of total alkalinity and turbidity observations, that physical-chemical data as obtained at the Lorain filtration plant can be used in the interpretation of open lake conditions obtaining in the west basin. In utilizing these on shore data it should be carefully borne in mind that under prevailing winds (1) Lorain appears to be sampling 24

70 6560 50 Ic 45I.0~~~~~~~~~~~~~~~~~~~~~~~~~0~ z - 40 -j w x (I) < 35 z M 230 Cr, co =1 a z -20- 0: I\.)~ ~ 15 0 -1tO 5-0 O — 0 10 5 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 10 LORAIN TURBIDITY, PRRM. Fig. 10. Adjustnent curve, Lorain turbidity to Rattlesnake Island turbidity.

the integrated water mass resulting from the mixing of the effluents of the Detroit River and the lesser streams entering the west end, principally the Huron, Raisin, Maumee, and Portage Rivers, and (2) data as obtained at Lorain are more representative of west basin conditions during seasons of normal or below-normal runoff than during periods of abnormally high runoff. It should also be remembered that during periods of winds from easterly quarters the lake circulation may be altered to the extent that Lorain may temporarily fail to sample west basin water. REPRESENTATIVE STATIONS FOR THE CENTRAL BASIN Since one of the chief parameters utilized in the selection of representative stations has been total alkalinity, it should at this time be pointed out that in the central basin there is a north-south horizontal gradient of total alkalinity in which values decrease toward the south. This situation is the reverse of that encountered in the west basin, in which lower alkalinity values are found in the north where the Detroit River enters the lake, and higher values in the south where relatively large amounts of admixed Maumee River water occur. The gradient existent in the central basin is apparently due to the bedrock formations underlying the lake, and to the very high alkalinity values found in the tributary streams of the Canadian shore. Both the central and east basins are underlain by shale and limestone; in the central basin the limestone is confined to a narrow region roughly parallel to the north shore, The remainder of the basin is underlain by shale. The dissolution of limestone by carbon dioxide in the bottom waters and the upwelling of these waters along the north shore may account for the higher total alkalinity values found in the northern portion of the central basin. The north-south gradient in alkalinity appears in the Buffalo Museum "Shearwater" data of 1929 (Fig. 4) and the University of Western Ontario data of 1947530 Assessment of representative stations for the central basin was largely on the basis of the 1929 "Shearwater" data, as data obtained by the University of Western Ontario was practically all confined to the northern pQrtion of the basin. Although the data of "Shearwater" cruise 2 of June, 1929, were the only data suitable for the construction of a circulation pattern, total alkalinity and turbidity data from -the remaining three cruises in July, August, and September 1929 were utilized in the analysis of the representativeness of central basin stations, Cleveland and Erie were considered as the possible south-shore representative stations for this basin, they being the only two which had not been eliminated from consideration on the basis of intake location, pollution effects, or some other factor. From circulation evidences, as well as geographic location, it appeared that Erie possessed better qualificatioms than Cleveland for the position of representative station for the central basin. The Erie intakes (there are two 26

plants, with intakes close to each other) appeared to be in such a position as to sample an integrated product of the easterly south shore current and the cross lake current from Long Point, The surface current pattern indicates that water from both these sources might be brought past the Erie intakes. Cleveland, on the other hand, is so far west as to be sampling predominantly the water of the easterly south shore current only, and further, analysis of the circulation suggests that the Cleveland intakes may at times sample water which is predominantly an unmodified effluent of the west basin. From "Shearwater" cruise 2 were available total alkalinities, turbidities, and water temperatures which could be used in analyzing the representativeness of Cleveland and Erie. It is obvious that as complete an analysis could not be performed here as was the case with Chandler vs. Lorain, since in the latter case data for the west basin were available over a period of years. Total alkalinity and turbidity observations obtained at Cleveland's Division and Baldwin filtration plants in 1929 were compared with values of these parameters at "Shearwater" stations 47 and 48, These stations were located 2 and 14 miles, respectively, north-northwest of the two plant intakes, and the depths at the stations were fairly comparable to the intake depths., The depth of the Baldwin intake is 28 feet and that of the Division intake 36 feet; station 47 was located in 38 feet of water and station 48 in 44 feet. The comparisons of the two filtration plants with data from stations 47 and 48, for each of the four cruises, are summarized in Table IIo In the case of total alkalinity, best agreement is between the Division plant and the average of the bottom values from stations 47 and 48. Both plants tended to run slightly below the surface values as observed at the stations. The best agreement of turbidity values lay between the Baldwin plant and the average bottom values of the two stations. In summary, the total alkalinity and turbidity data as obtained by the two Cleveland filtration plants are, to a fair degree, representative of these two parameters as they occur somewhat farther out in the lake. Evidence derived from the circulation pattern of the lake, however, indicates that at best Cleveland is sampling water from the extreme western portion of the central basin, and may frequently sample relatively unmodified west basin water. The strong turbidity gradient along the south shore in the vicinity of Lorain and Cleveland as observed by "Shearwater" cruise 2 (Fig. 3) is indicative of the presence of west-basin water. At Erie, observations of total alkalinity, turbidity, and water temperature as obtained at the Chestnut Street filtration plant were compared with values of these parameters as obtained by"Shearwater" cruise 2 (Erie's West filtration plant did not become operative until 1952). Comparisons were made in two ways; first, all "Shearwater" stations in the central basin, including those to a dis27

tance five miles east of Erie, were combined to obtain mean values of total alkalinity and turbidity for surface, bottom, and average of surface and bottom. This was done for each of the cruises, that is, June, July, August, and September. Secondly, stations 37, 35, 47, and 48 were similarly combined to obtain average values for each of the cruise months, These stations lay, respectively, three miles north of Ashtabula, 3 miles north of Fairport, and 2 and 14 miles NNW of Lorain, These four stations were indicated by the circulation pattern as lying within the eastward south-shore current which passes the Erie intakes; they were compared, separately from all the central-basin stations, with the Erie data in an effort to determine whether Erie might be more representative of this water than of the central basin as a whole. Stations 37, 38, 47, and 48 will hereafter be referred to as "selected stationso" Temperature data from the "Shearwater" cruises were treated similarly to alkalinity and turbidity, with the following two exceptions: (1) Temperature was obtained at each station at surface, 10 meters, and bottom. Only the surface and 10 meter observations were compared to the Erie values, since these were nearer the intake level of the plants and gave a more realistic test of Erie's representativeness. (2) In addition to data from the June, July, August, and September cruises, temperature data from a May, 1929, cruise were available, although alkalinity and turbidity data for this cruise were lacking. Comparisons of averaged "Shearwater" data and Erie's Chestnut Street plant's monthly average data are summarized in Tables III and IV. It may be seen from Table III that, compared to the average of all stations, alkalinities observed at Erie are consistently low, by 4 to 7.5 parts per million. Erie's values agree best with the bottom values of the selected stations, which were located within the south shore current. The Erie intakes appear, then, to sample predominantly water from the south shore current, rather than a well integrated product of water from the entire central basin. Erie plus 3 ppm would appear to give a working estimate of selected-station alkalinities under most conditionso That Erie is not representative of the northern and western parts of the central basin is shown by a comparison of total alkalinity data at Erie with data obtained at University of Western Ontario stations 2, 3, 4, and 5 between 1947 and 1953 (Appendix II), These stations were situated 6, 14, 20, and 26 miles south of Point aux Pins. Alkalinity values at Erie were as much as 28 ppm below those observed at UWO stations, and only at one time were the Erie values less than 11 ppm below the station values. The existence of a decreasing north-south horizontal gradient of total alkalinity in the central basin has been discussed above and is reflected in these two sets of data, Turbidity values observed at Erie are consistently and irregularly higher than those of the open lake as indicated by the "Shearwater" data. This is true for both "all stations" and "selected stations~" It is likely that turbidity at Erie is influenced locally by the sediment-suspending effects of wind or current action, and it is to be expected that the plant data should reflect these influences in higher turbiditieso 28

TABLE III All Stations Selected Stations Surface Surface Surface Bottom and Surface Bottom and Erie Bottom Bottom Alkalinity June 99 97o 5 98 95 94 95 92 July 101 98 99, 5 96 95 95 92 Aug. 97 96,5 97 97 95.5 96 93 Sept. 98 98 98 97.5 99 98 93 Turbidity June 4 6 5 9 11 10 12 July 3 6 5 5 6 5 10 Aug. 2 5 4 5 6 6 16 Sept6 4 5.5 5 7 7 7 20 TABLE IV Temperature, ~C Month All Stations Selected Stations Month Erie Surface 10 Meters Surface 10 Meters May 8.4 6.6 9,8 7.8 1107 June 17.6 13.2 18.0 14.5 17.4 July 20.2 17.7 21o6 19.1 21.6 Aug. 20.9 20.0 21.4 20 7 21.8 Sept. 19.4 19,4 19.7 19.6 20.3 From Table IV, it may be seen that agreement of intake temperatures at Erie with those observed by the "Shearwater" is excellent. Erie's values coincided more closely with surface temperatures than with 10-meter temperatures; correlation of Erie with the selected stations is a little better than with the entire basin, but the difference is slight. It should be noted that agreement was least good in May, when the intake water was warmer than that of the open lake. This is to be expected, since this correlates with the season of spring warming, when near-shore waters would have attained a higher temperature than those farther offshore. Comparisons of intake temperatures at Erie were also made with surface temperatures (both in centigrade) observed at University of Western Ontario stations 2, 3, 4, and 5. They are summarized in Table V. 29

TABLE V 1947 1948 1949 1950 1951 Erie UWO Erie UWO Erie UWO Erie UWO Erie UWO April 8.2 4 May 906 11.9 11.2 11.5 June 16.5 16,0 18 4 4 196* 16.8 16.9 15.7 18.6 July 18.8 22,1* 20.2 20.3 20.1 24.4* 20.3 20.8 21.6 22.9 Aug. 22.2 25.7 22.7 23.5* 24.3 24,2 22.5 21o9* 22,8 23.2 Sept, 22.3 186 186 19.9 17.9 22,4* Oct. 16,2 19,4* *Based on single observation from station 2. Agreement of Erie intake temperatures with those as observed at UWO stations is, for the most part, quite goodo Once again, the effects of alongshore warming in the spring are indicated in the one set of April temperatures, where the water at Erie was nearly twice as warm as that in the open lake. More rapid autumnal cooling of the shallow onshore water is shown in the September and October data of 1949 and 1950. It must be remembered, as has already been pointed out, that strict comparability between observations obtained at Erie and those from the open lake cannot be implied, since it has been necessary to compare monthly averages based on a relatively large volume of data at Erie with either single days' observations, or averages based on no more than four observations, from the open lake. Considering the paucity of open lake data available, the comparability that has been obtained must be considered very good. On the basis of total alkalinity, Erie must be considered a good representative station for only the southern half of the central basin. In regard to water surface temperatures, however, those observed at Erie do not differ materially from those of the entire basin. This apparent discrepancy is resolved when one considers that surface temperatures throughout the basin are controlled by very nearly the same climatic regimen and should not exhibit too much variability, except in regions of upwelling. One appears to be justified, then, in accepting the intake temperatures at Erie as being representative, within a few degrees, of the average surface temperatures existing anywhere within the central basin. The strongest exception to this representativeness would be in comparing Erie's temperatures with those along the north shore, where the existence of the counterclockwise eddies appears to result in upwell3o

ing of cooler subsurface water, the temperatures of which would not be typical of surface temperatures over most of the basin, Since Erie can be considered chemically representative of only the southern half of the central basin, conditions obtaining in the basin as a whole could be more accurately depicted if there were two representative stations, one on the south shore (satisfied by Erie), and one on the north. Although a number of municipalities in the province of Ontario possess filtration plants which obtain water from Lake Erie, none of these make routine physical-chemical analyses of raw water as far as this investigation has been able to determine. Analyses of intake water at Port Stanley, made by the Industrial Minerals Division, Mines Branch, Canada Department of Mines and Technical Surveys (Thomas, 1954) indicate a degree of comparability between this water and that sampled by UWO stations 2, 3, 4, and 5. Intake water at Port Stanley was subjected to complete analysis once monthly from February 1948 to February 1949. During this period the UWO stations were visited during June, July, August, and September. The average total alkalinity for the four samples obtained during these months at Port Stanley was 100 ppm; the average from all depths at the UWO stations was 106 ppm. Considering once again the scanty data available for comparison, this is good agreement. Centigrade temperature data from the two sources were compared on a month-to-month basis. April May June July August September University of 4.2 --- 12.7 16.3 20.3 21.6 Western Ontario Port Stanley o.6 3 -3 4.4 15.6 18.3 15.6 The notable tendency of the Port Stanley temperatures to remain consistently below those as observed at the open-lake stations is probably due to upwelling occurring near the north shore in the Port Stanley vicinity, caused by the previously mentioned eddy occurring here. The proximity of Port Stanley to this upwelling makes its value as a representative station questionable, since it would, at different times, be effectively sampling different depths. Hence, variability in observations would have to be assessed partially on an unknown basis of effective sampling depth. The deduced pattern of surface circulation indicates the possibility of Port Burwell as a better location for a north shore representative station, since it lies at the extreme eastern end of the eddy, and near the area of strong onshore current shown by the FWS drift bottle returns. It is not known at present whether this municipality has an intake in Lake Erie; if water is being drawn from the lake, the initiation of a program of obtaining observations such as total alkalinity, turbidity, and temperature, might well result in the accumulation of a valuable body of limnological data. 51

REPRESENTATIVE STATIONS FOR THE EAST BASIN The only possible representative station for the east basin is the Erie County (New York) Water Authority filtration plant located at Woodlawn, N. Y. The Niagara-Mohawk power station at Dunkirk, N. Y., obtains physical-chemical data, but its records are available for only a few years back and assessment of its representativeness is impossible. Because Woodlawn has obvious weaknesses (discussed below) Dunkirk should be evaluated as soon as simultaneous data are available. Data of 1929 from the Woodlawn plant were compared with open-lake data obtained by the "Shearwater" in the east basin in 1929 (1928 data are also available from previous "Shearwater" cruises, but data from Woodlawn do not include that year.) Comparisons were made of total alkalinity, turbidity, and temperature. The procedure was similar to that used for Erie, in that data from Woodlawn were compared with monthly averages of observations from the entire east basin, and also with certain "selected: stations which, according to the deduced circulation pattern, lay up-current from the plant's intake. The latter stations were all near the south shore, extending from just off Woodlawn to about the Pennsylvania-New York state line. Results are summarized in Tables VI and VII. TABLE VI All Stations Selected Stations Surface Surface Surface Bottom and Surface Bottom and Woodlawn Bottom Bottom Alkalinity June 100 98 99.5 96 95 96 93 July 99 98 99 98 97 97.5 90 Aug. 98 97 97.5 98 97 97 91 Sept. 98.5 98.5 98 98 97 98 99 Turbidity June 13 16 14 14 5 15 15 13 July 6 20 13 8 9 8 7 Aug. 4.5 13 9 6 7 6.5 8 Sept. 0.5 8 4,5 0.6 1 1 13 32

TABLE VII Temperature, OC All Stations Selected Stations Mon th Woodlawn Surface 10 Meters Bottom Surface 10 Meters Bottom June 13 11 8 12 --- 12 17 July 19 17 12 20 --- 18 20 Aug. 20 18 14 21 --- 20 18 Sept. 21 20 16 21 --- 20 15 Total alkalinity as observed at Woodlawn is consistently lower than openlake observations for the east basin, as obtained by the "Shearwater." The tabulations of Table VI indicate that this is true for both "all stations" and "selected stations," except for September, when the average value at Woodlawn for that month closely approximated open-lake values0 Order-of-magnitude agreement is quite good, however, and lower alkalinities at Woodlawn may be due largely to the effects of acid waste effluents from steel mills which located in that vicinity0 Probable variations in quantity of acid waste make a correction factor futile0 Average monthly values of turbidity at Woodlawn agree well with those from the "selected stations," and, for the most part, fairly well with those from all stations in the east basin0 The only notable discrepancy is in September, when local disturbances (probably winds) apparently resulted in higher turbidities in the vicinity of the intake0 Temperature observations from Woodlawn do not agree as well with open-lake data as do the plant data at Erie0 This may be largely due to the plant's being located on the extreme east end of the lake, where the intake is exposed to the full effect of the internal seiche, the magnitude of which can be quite large0 This might explain the lower temperature at Woodlawn for September, when the average of 15~C corresponded closely to the average of bottom temperatures for all stationswhereas in June, July, and August intake temperatures corresponded more closely to average surface temperatures for both "all stations" and "selected stations." LAKE ERIE REPRESENTATIVE STATIONS: A SUMMARY It has been shown that for each of the three basins of Lake Erie, a filtration plant exists whose raw-water data correlate sufficiently well with openlake data to justify their establishment as the most representative stations for 33

their particular basins. Lorain, Ohio, and Erie, Pennsylvania, chosen as representative stations for the west and central basins, respectively, appear to be more reliable than Woodlawn, New York, the one evaluatable station for the east basin. Waste effluents from steel mills and seiche activity appear tO affect the representativeness of alkalinity and temperature data at Woodlawno The intakes at Lorain and at Erie appear to be relatively free from the effects of local pollution and seiches, and it is believed that data obtained at these two plants are sufficiently indicative of open-lake conditions to permit their application to practical limnological problems, particularly in regard to the assessment of long-term physical-chemical conditions in the lake. When and if Erie and Woodlawn are seriously used in "watching" the trends within the lake, their actual degree of representativeness should be more definitively determined by more offshore cruises4 Scarcity of offshore data has been a serious limiting factor in their assessment. Dunkirk, New York, may be a much better representative station for the east basin and should be evaluated as soon as possible. A REPRESENTATIVE STATION FOR LAKE MICHIGAN Through the kindness of Mr. Russell L. Johnson, Engineer in Charge, Northern Peninsula Office, Michigan Department of Health, we are able to indicate a representative water plant on Lake Michigan. In collating local wind and circulation near Muskegon, Michigan (as indicated by Ayers et al., 1958) with raw water temperatures from the recording thermometer at the Muskegon water plant, Mr. Johnson has very clearly shown that under different winds Muskegon samples both surface water from about 20 miles out in the lake and subthermocline water from the region outside Muskegon. His studies (personal communications) show that under south, southwest, or west winds surface waters from the open lake approach Muskegon. On the second day of winds from these directions notable rises in raw water temperature occur, and by the fourth day of such winds isotherms originally about 20 miles offshore are being sampled by the intake. Referring to Fig. 4 of the Lake Michigan paper (Ayers et al,, op. cit_), Mr. Johnson says, "Figure 4 shows that, on June 28, the 170 isotherm for the surface water was located several miles offshore at Muskegon. On June 29, according to Fig1ure5, this isotherm had reached shore in this part of the lake. At intake level off Muskegon, the water temperature started rising at about 0100 hours on June 29, the day of Synoptic Cruise V. It reached 17~C (62o60F) late in the day on June 30 or early on July 1." Winds at Muskegon were from the south for six days beginning on June 27. His studies also show that the atypical east-shore south current observed in Lake Michigan on 9 and 10 August 1955 in Synoptic Cruises VI and VII probably began on 7 August, for on that day the raw-water temperature at Muskegon began a sharp decline which lasted through 9 August, and were only beginning to rise on the 10tho During the sharp decline, temperature fell from 80.00F (26,6~C)

to 45.00F (7.2~C) between 0630 of the 7th and 0430 of the 9th. Figures 5, 16, 28,and 41 of the Lake Michigan paper all show 762' water to be subthermocline water. This temperature break accompanied north winds and east winds (offshore winds) that began on August 7th and continued for at least five days. Mr. Johnson's studies also indicate that northwest winds cause strong upwelling at Muskegon. It appears reasonable to believe that Muskegon on the fourth day of winds from the south, southwest or west is sampling surface water from about 20 miles (estimated) offshore. It also is reasonable to believe that Muskegon on the third day of winds from the northwest, north, northeast, or east is pumping subthermocline water representative of the hypolimnion of the deep basin outside Muskegon. Mr. Johnson has authorized our use of the above review of his studies. A TECHNIQUE FOR DETERMINATION OF WIND PATTERN OVER A LAKE Basic to the study of properties of a large body of water is knowledge of its currents. The distribution of water properties such as alkalinity and turbidity is influenced by the movement of lake currents. Current variations are brought about by two principal factors; 1) temperature distribution of the water, and 2) wind at the lake-atmosphere interface. The techniques of dynamic height determination derived from considerations of the density distribution of water in order to compute water currents are well known in oceanography and have been used with success in previous studies of some of the Great Lakes (Ayers, et al, 1958; Ruschmeyer and Olson, 1958). The dynamic height method yields an integrated depiction of temperature effect and the wind-distributed field of density. In this depiction the temperature factor is semi-conservative and varies at a relatively slow rate, while the wind factor varies on a day-to-day basis. The wind pattern over a lake, then, is the dominant factor in the pattern of water currents in the lake. For large bodies of water that are relatively shallow, such as Lake Erie, currents are much more rapidly changed than in deeper lakes of comparable area. This is because shallow water does not represent as great a momentum sink as does deep water. It has been found that current patterns in western Lake Erie, for example, are variable, and frequently vary on an intra-diurnal time scale (FWS Cruise Report III, Ayers, 1958). There is also evidence elsewhere (Saginaw Bay, Johnson, 1958) to indicate the wind-produced changes in shallow water movement may take place with as little as two hours subjection to a new wind regime. It is important, therefore, that the wind field be determined as accurately and frequently as possible. 35

A technique of kinematic analysis of the atmosphere, known as the streamline wind analysis method, makes possible an accurate computation of the windproduced currents which affect the distribution and transport of variables that make up the water quality (e.g., alkalinity, turbidity, chemistry)0 It is also a valuable means for reconstructing the wind regime and current patterns in the Great Lakes at any time during the past 60 years0 It is, therefore, both a climatological and synoptic aid in water current analysis. The technique utilizes reports of the wind vector from many observers taken simultaneously; hence analyses made from these data are truly synoptic. The frequency of reports (and hence possible analyses) is a function of their history. Before the onset of World War II, the frequency of reporting was once per day. After the close of the war, reports became available on an hourly basis. Data density has increased in like manner. For example, in 1899, there were four stations surrounding Lake Erie that reported wind data once per day. At present, the number of stations which surround western Lake Erie alone number 21, all of which make hourly reports of most meteorological variables including the wind vector. Some wind records of this group are autographic. In addition to the hourly stations, Powers et alo (1958) have shown that there are ten Coast Guard stations around the western basin of Lake Erie reporting the wind vector at either 4- or 6-hourly intervals. On a once-per-day basis there are an additional five water plants that surround the same area of Lake Erie that report the wind vector. Finally, there is a variable number of lake vessels that are equipped with anemovanes which report periodically when operating more than 4 miles from shore. Not counting the vessels, there are three dozen sources for wind data over the western basin of Lake Erie alone-a ten-fold increase in data density since the turn of the century. The hourly wind reporting stations in the vicinity of all the Great Lakes which are available at present are represented by the station circles shown in Fig. 11 Each station reports all meteorological variables including the wind vector0 The basic difficulty in making a wind analysis is not just a function of the data density, but primarily is dependent on the fact that the wind is a vector quantity. It is possible to draw charts and graphs of vector quantities, but it is difficult for the analyst to account graphically for the variation of the vector by one system of lines or isoplethso It is simpler and more accurate to analyze the vector in terms of its two scalar components, speed and direction, by preparing a graph of each scalar separately. Figure 11 shows the first step necessary in preparing an accurate analysis of the wind direction field. The two digits above the station circle are the reported wind direction in tens of degrees reckoned clockwise from north (36), calm being code 00. The wind data shown are those actually recorded at 1300 EST 23 October 1958o With a field of numerical values at hand to express the wind directions, equal-valued lines called isogons may be constructed. The purpose of the isogons is two-fold. First they give continuous representation of the wind direction

95- 900 8~0 800 750. w~'. ~ J NEN o/ Oe 4 4ISOGONS (DEGREES) 0 4 NW 2 NE 0....... E Q U I- D IR E C T ION A L N~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ LINE SEGMENTS SE~~~~N ~~~~~~,,, N~~~~~~~~~~~~~~~~~~~~~~~~~~,,,;ir" ~ 1W S r / E. 02 ~~~~~~~~~~o: i / 0 0 1 3 %~~~~~~~~~~~~~~~~~~~O 1 ~~~~~~~~~~!::-'~~~~~~~~~~~~~~ ~~~~~~;~ i-:::!:~:::?i::?~:::?:":'iilli....li.~.i~, ~ EN 9 2 12 NE 32 05~~~~~~~~2 0~~~~~~~~~~~~~~~~ % 29~~~~~~~~~~~~~~~~~~~~~~~~~~~~~' O ~, 26.ii../ sw \- h__6. i7 o W O 20 O 20 i~W 07 2 9 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.._.....i H:: 2o~~~~ Nw 18 o - o1 0 0. 0O 160~10 9~~~~~~~~~~~~~~~~~~~~~~~~ 24 6 0 0 82O 2 9 2 92 29 0 07~~~0 2 ~~~~~~~~~~18 34 lo 0 W 0~ /~8t W W 5 2 S 2 0 2 0 2 26 0F2O \~='~FJ 0 20 0 28 24E0 2 2 24 60 80 0 0 27 0 2s ~S 0.O S SW 0 18 27 0 EL2~~~~lp~ 5 2080 24 O O 06~~~~~~~~~ 40260202 26 1 8 0 0O E~~ W-~ 0 02 24 0 2 7 2 0 24 Pal 0 2 7 - SE 0N:24 W 2 ~9 Fig. 11. Isogon analysis. Data above station circle wind direction in tens of degrees. Solid lines isogons. Broken lines equi-directional line segments.

field. That is, everywhere along any one isogon the wind direction is the same, The isogons also provide interpolated information of the wind direction between stationso IAn Fig~ llb the isogons are labeled by letter abbreviations, NE, SW, etco It is difficult to draw, directly, the streamlines which depict the wind direction field because of the lack of information between stationso Only a crude first approximation to direction field is possible by the direct approach. First, direction arrows must be constructed at each station to show the wind direction graphically. Then streamlines may be drawn, but with confidence only if the data density is high. In only a few locations of the United States (viZo, around the major metropolitan centers) is the station coverage dense enough to approximate the detail possible from an isogon analysis. In the interests of accuracy, therefore, the isogon procedure is recommended because it multiplies the density of the data field. The second step in preparing the streamline analysis is to construct short line segments across each isogono Each line segment is oriented according to the wind direction of its isogono That is to say, all line segments on the "north" and "south" isogons, for example, are drawn parallel to the local meridians no matter how the isogon itself varies across the chart; all segments on NW and SE isogons point in these directions; etc. The number of segments drawn is completely arbitrary. What has been accomplished by the procedure so far described, and illustrated in Figo 11, is to give the analyst a chart composed of as many "wind observations" as he desireso Instead of being restricted to wind data reported by the stations alone, he now has a limitless number of wind directions by which to construct streamlines to show the air-flow at a given moment0 In actual practice, isogon intervals of 30 to 45 degrees (those of Fig. 11 have an interval of 45~) with line segments one or two latitude degrees apart is a sufficiently detailed field of data from which to draw streamlineso The third step in the procedure is illustrated in Fig. 12o For simplicity, only the line segments from Fig0 11 are reproduced0 The pattern of air flow is shown by the solid streamlines which are constructed so as to be everywhere parallel to the line segmentso This is the only requisite on the construction of streamlines; the speed of the wind is not involved in this analysiso Streamlines can fork and join, but only asymptotically. Exceptions are at singular points where the wind is calm and the wind is considered omni-directional. The number of streamlines constructed is arbitraryo Figure 12 is a completed analysis of the wind direction field over the Great Lakes and vicinityo The complete wind field, however, is not specified until its speed is analyzed0 This is shown in Fig0 13 where the two-digit figure appearing beneath the station circles is the wind speed in knots0 The dashed lines are equal-speed isopleths (isotachs) drawn to the numerical data in intervals of 5 knots0 The patterns in the figure show the variation in speeds of the air motion0

950 90g 85~ 80~ 750 \\ \I /~/ ~ ~ STREAMLINES iiII EQUI DIRECTIONAI. LINE SEGMENTS I~~~~~~~~~~~~~~~~~ 45~ ~~~~~~~~~~~~~~~~~~~~ I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~t 1~~~~~~~~~~~~~~~~ Fig. _12. Stream-line an_-Lysi1s. ]Broken _-lines ecqui-dilrecti onal line segments'. So~lid }_lines st. ream sinLles.

95~ 900 85~ 80~ 756 t 0' \I03xs ~'~~~~~~~~~~~....' 0 03 ~~~~~~~~~~~~~~~09 i' /~~lo 088-d 10~~~~~~~~~~~~~~~~~~~~~ 7 09 0~~~~~~~~~~~~~~~~~~~ 06 08~~~~~~~~~~~, 0 I~~~~~~ ~ ~ ~ ~~~~~~~~0,0 0 I 0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~0 U07'-'ll,~ 0~~ ~ ~~............. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~02 06 8-t, ""-O-~ 0 /~.~ — "5 10~~~~~~~~~~~~~~~~~~~~~~~-.. 07 t -- ~~~~o: [ -0 ~~~~~~~~0 0~~~~~~~~~ 0 09 o "',.~~~~~~1 07 1 12~~~~~~~~~ 08 " 06.-0,~~~~~~~~~~~~~~~~~~~~~~1 0 I~~~~~~~~~~~~~~~~1 0.0...~........::'...fiii',,, I,- I~~~~~~~20I t,,~~~~~~~2 12 o~ /0 0 0~~~~~~~,'%,,, ~_u s i,.., // ~~14 0 20~~~~~~~~~; ".~ 2i:::ii:iii:~ 08 8 0 0% 04t 0 ~ ~ ~~~5' —,0 0' t8 %20 - -. o 02 // —'8 01 0 6 0 6 7 0 13.85,% 0 50 i 1 6.....,' -.~~ 2, ~~~~~~~~~~~~~-..0 20 009tiiiii::i:::;!'1::iiiii~i;ii? t0,O 0 0 O r~ ~~~~~~~~~~~~1/t -15' 7,20 ~~~~~210 0 0 t c 07~~/1!iiiii;iii~;:' 06 12 Ioo0 ~~~~~~~~~~~~~~~~03 0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 0 0 0,~~~~ ~ ~~~~~~~~ ~~~~~~~~,- O,, 2, O 06 o) o,. 5 0, o', ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 0 4%07.-5-O 03 7 01I i, / I~~ ~ 0 -00 "~~~Fg 13'stc nlss aabnahstto icewn pe nkos Dahe lie _-/,1s' 8otah.....

When isotachs are superimposed on streamlines the resulting chart gives a complete representation of the horizontal wind field. This is shown in Figs 14. The speed and direction of the wind at any point over land or lake is given either directly when the streamlines or isotachs pass over the point, or by linear interpolation between isopleths when the desired location falls between them. The effect of the wind stress on surface water movement can be computed at this point by any suitable technique such as those described by Ayers et al. (1958) and Hunt (1958). The streamline technique of representing the wind field at the water-air interface will give more definitive surface current patterns than from conventional techniques. This means increased knowledge of trajectories of water sampled for such parameters as alkalinity, chemistry, turbidity, and temperature. The wind field portrayed will be no more accurate than is commensurate with the accuracy and density of individual data sources, but from a given set of data the technique provides the most accurate analysis of the wind velocity field. Historical as well as present wind data may be analyzed by the streamline technique. RAINFALL IN THE LAKE ERIE BASIN SINCE 1810 As a part of the accumulation of the historic background of the Lake Erie aquatic environment, searches of the literature for old meteorological data have been carried out, During these searches we have uncovered sufficient rainfall data to allow the reconstruction of a practically continuous rainfall graph extending back to 1810, As is also the case with lake levels, it is greatly to be desired that rainfall records be extended back into the period when the Great Lakes watersheds were in essentially full-forest condition, The oldest rainfall records pertaining to the Ohio region are from a gauge maintained by a Dr. Hildreth of Marietta, Ohio, during the years 1819-1823 and 1828-1832. These records, however, overlap with records from a gauge at the Pennsylvania Hospital in Philadelphia during the years 1810-1815, 1815-1819, and 1827-1837. The overlap of the Marietta and Philadelphia records covered the 5year period 1828-1832, The data for the overlap period are in terms of total rainfall and mean annual rainfall during the periods. Figures for the individual years are not available. The mean annual rainfall at Marietta was slightly greater than that at Philadelphia and all the data from Philadelphia have been increased by an amount sufficient to make Philadelphia equal to Marietta during the period of overlap. The corrected Philadelphia data undoubtedly are in error, but to date they are all that are available for the 1810-1827 period. They have been used, as corrected, in the computation of the mean annual rainfall of the 1810-1958 period (discussed below). No attempt has been made to correct the Marietta records to stations within the Lake Erie basin0 This may be attempted later if circumstances indicate it to be desirable. As the data now stand they show a good degree of agreement with the old lake levels (discussed later): 41

950 900 85~ 80~ 7 5~, ~iifj~iiiiii~~'.../ STREAMLINES 1\,~~~~~~~~~~~05 r~~~ ~~~ "'Ji(i? I SO TA CHS (KNOTS) I~~~~~~~~~~~~~~~iiii!,~~ /', I I ~ii~iijilijiii~iiliii~Yii~~l iiiii iiiiiiiii~i::i:i............. I~~~~~~~~~ % I'..... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.....? 05',15 i:::::::10 Ni X. % 20~~ JI~~~~~0 %~~~~~~~~~~~~~~~~~~~~~~ \ ~~~~~~~~~~~~~~~~~~~~~'15,,iii~iiii:/':. ~~~~ ~:::::::::::::::::::," ~,',,! i~:!i:::i:::i;~ ~ ~ oi lnssralnsdahdiesso....',' ~ "* %/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Biii:~~~~~l~lll:liil E1::::::11I:::i:l::: 15 """i' /~\~~~~~~~~~~~~~~~~~~~~~~~~~ / aali~s:~R1~i~ 0, /-.~~~~~~ s,,, /, /0 / ~~~~~~~~~~~~//, \ I' ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~:ii~:I:::::j:::::~~ - -,05'+,tii~i \ r::::::::i:::i:::::::,..__jr/:: / y: \ I ~~~~~~~~~~~~~~~~~~~:~s~~~~~~~~~~~~, 0,, /,o~ _. ---—.:iiii~~jiii,:'::~g::...::::::::::;: }_~.;;:i o:il11~e s'r ~g1~s cll;a, she(:l 11 ~es lsota,~hs.

high lake levels following at the end of periods of above-average rainfall and low lake levels coming at the ends of periods of below-average rainfall. Rainfall records, pertaining to the Lake Erie region directly, for the period 1838 through 1850 are from a gauge at Western Reserve University at Hudson, Ohio; Rainfall data for the year 1859 is available, to date, only for Lake Huron. This has been corrected into an estimate for Lake Erie by using the rainfall ratio of the two lakes for the ten-year period 1871-1880 inclusive. The Lake Huron figure for 1859 and figures for Lake Erie in 1860-1867 inclusive are from an early report of the Chief of Engineers, U. SO Army Engineers. The reference to this source and to the others used are indicated with the data in Table VIII and given in full in "Literature Cited)" Precipitation data for the land area of Lakes Erie-St. Clair are given in Horton and Grunsky (1927). These data cover the years 1871 through 1922. Data of the U. S. Lake Survey, for the years 1900-1958, were very kindly provided by Mr. W. T. Laidly of the Surveye The overlap years (1900-1922) between Horton and Grunsky and the U. S. Lake Survey allow an assessment of the degree to which the inclusion of the Lake St. Clair basin by Horton and Grunsky may have interfered with the strict applicability of their data to the Lake Erie basin alone. Maximum variation between the two sets of data in the overlap years was 2L27 inches; minimum variation was 0,04 inches) with Horton and Grunsky being higher in both cases. The mean variation during the 23 years of overlap was 0.19 inch with Horton and Grunsky being the lower. The overlap years and the comparison of Horton and Grunsky to the Lake Survey are shown in Table VIII. Total rainfall in the years for which there are figures has been summed and divided by the number of years for which there are figures. These figures, including the corrections, indicated above, yield a mean annual rainfall value of 35C55 inches for the period 1810-1958Years of above-average and below-average rainfall are given in the following table, All hyphenated figures are inclusive, Above Average Below Average 1810-1814 1815-1819 1819-1837 1838-1841 1842 1843 1848-1850 1860 1862 1863-1865 1866 1867 1873 1871-1872 1876 1874-1875 1878 1884 1880-1883 1886-1889

TABLE VIII RAINFALL SINCE 1810 Philadelphia (Foster and Whitney, Pt. II, p. 337) given: 1810-15* (5 years) 185.68 inches. 1815-19 (5 years) 151.14 inches. 1827-37 (11 years) 451.05 inches. Annual mean 41.00 inches. *Taken as 1810-14, inclusive. corrected: 1810-14, incl. 206.64 inches. Annual mean = 41.535 inches. 1815-19, incl. 168.20 inches. Annual mean = 33.64 inches. 1827-37, incl. 501.93 inches. Annual mean = 45.63 inches. Marietta, Ohio (Foster and Whitney, Pt. II, p. 337) 1819-23 (5 years) 202.83 inches. Annual mean = 40.57 inches. 1828-32** (5 years) 228.17'* inches. Annual mean = 45.63 inches. **Omitted in computing mean of 1810-1958 period. Hudson, Ohio (Foster and Whitney, Pt. II, p. 338) mean of 1838, 1839, 1840 54.12 inches 1841 28.43 inches 1842 36.11 inches 1843 26.74 inches 1844 35.73 inches mean of 1848, 1849, 1850 39.365 inches Lakei HJron (Rept. Chief of Engin. for 1868, Pt. II, p. 991) given: 1859 27.90 inches corrected: 1859 29.02 inches for Lake Erie Lake Erie (Rept. Chief of Engin. for 1868, Pt. II, p. 991) 1860 31.29 inches 1861 35.58 inches 1862 36.58 inches 1863 31.69 inches 1864 34.00 inches 1865 32.67 inches 1866 38.15 inches 1867 28.61 inches Lake Erie —St. Clair (Horton and Grunsky, 1927, iable 46, p. 112) 1871 30.9 inches 1872 29.9 inches 187- 38.8 inches 1874 29.2 inches 1875 535.6 inches 1876 395. inches 1877 355. inches 1878 45.3 inches 1879 55.5 inches 1881 40.5 inches 1881 41.2 inches 1882 57.1 inches 1883 58.4 inches 1884 52. 5 inches 1885 57.4 inches'J. S. Lake Srvey 1886 321.9 inches 1887 51.6 inches 1915 52.26 inches 1888 29 3 inches 94 32.8 inches 1889 29 5 inches 192[ 30.62 inches 1890 41.9 inches 1026'9.01 inches,891 5210 inches 1927 351.47 inches 1892 38 4 inches 1928 31.20 inches 1.893 06 0 inches 1929 38.81 inches 094 50.5 inches 1930 26.77 inches 1895 28. inches 1951 51.9 inches 1896 54.7 inches 1932 34.58 inches 1897 0139 inches 1905 28.0 inches,1898 5 3" inches U.S. Lake Survey —Lake Erie 1934 24.88 inches 1809 2902 inches 193a 29.96 inches 1)00 52 6 inches u.5 inches diff. 0.07 average 32.57 1936 28.70 inches 190i 30. inches 30.46 inche 0o04 (used in 30o.48 1937 40.24 inches 1~02 56.7 inches 3.4- inches 021 computing 36.60 1938 33.6 inches 190C 56 4 inches 6.09 inches mean of 36.25139 51.19 nches 174 35 6 inches 54.16 inches -! 56 1810-1958) 33.38 1940 36.44 inches 1( 31 9 inches 8.8 inches -168 274 1941 26.53 inches i906 62 6 inches 3. inches -102 33.11 1942 3.8 inches 1907 34.7 inches 56.21 inches - i 5.46 1943 3.7 inches 108) 50. 3 inches 0.1! inch's -0o61 30.61 1944 50.18 inches 1909 6 67 inches 38.00 inches -130 949 40.2p inches e1(10 - t inches 33 38 inches 1122 33.l9 1ou( 0 O.7 inches 1911 3660 inches 5., ices 048 35.76 1947 38.91 inches 1912 54 3 inches 4.6 ichs 036 54.48 1948 6.26 inches 191 38.1 inches 8. 0 inchl- S o. o5 38.o8 1949 4. nches 1914 nches 3 6 inch 7 33. ches 1915 34.7 inches 5.61 inches -091 3.16 1951 37.41 inches 1.16 34.0 inches 33.83 inches 0 17 33.92 9" 31.00 inches 1917 37.4 inches 30.13 inches 2.27 6.27 195ins 1918 31. 9 inches 31.59 inches O.1 - 1954 1..15 6nches 1919 32.3 inches 32.67 inches - 7 15 3.9 inches 1320 33.6 inches 31.94 inches ~66 16 6.2 inches 1921 34.3 inches 5.07 inches -0774.69 1957.2 inches 1922 30.9 inches 31.62 inches -0 72 51.268 51. 12 inches Total -4. I Mean diff.. 1) 44

Above Average Below Average 1885 1891 1890 1894-1901 1892-1893 1904-1908 1902-1903 1910 1909 1912 1913 1914-1916 1917 1918-1925 1926 1928 1929 1930-1936 1937 1938-1939 1940 1941 1942 1944 1945 1946 1947-1948 1949 1950-1951 1952-1953 1954 1955 1956-1957 1958 Years not specifically listed in this table fell practically on the average. PRE-1860 LAKE LEVELS OF LAKE ERIE In our search for indices of past conditions of the aquatic environment we have come across a fairly substantial amount of data on lake levels of the years prior to 1860. While these old lake levels are at present of chiefly academic interest, they do have at least potential value in the search for indices inasmuch as they express the integrated effects of hydrology and progressive deforestation. The present hydrograph of lake levels put out by the U. S. Lake Survey, in extending back only through 1860, does not reach to the period when the Great Lakes watersheds were in essentially full-forest conditions. The present study allows the delineation of periods of high and low lake levels back to 1796. Accuracy of the lake height figures falls off as one goes into the period earlier than the high-water of 1838, but appears to be substantial back to the low-water of 1819-20. Earlier than the latter period, the records become predominantly the recollections of early settlers and are decreasingly accurate, but at least approximate figures can be deduced back to 1800-02. Prior to that time the data are merely qualitative. Dominant high-waters are indicated in 1858-59, 1838, 1815-16, and 1800-02. Pronounced low-waters are indicated for the years 1819-20, 1809-10, and 1796. Also indicated quite clearly is a progressive downward trend in lake level from 1860-1796. The meaning of the latter is unknown, but it might be a reflection of the presence of the forest with its concomitant increased water loss in transpiration, interception, and retention~

The complete lake level data are given in Table IX; they have been obtained from the following sources (see Literature Cited for complete references); Houghton et al. (1848); U. S. Army Engineers (1870); Foster and Whitney (1851); Gilbert (1898); Houghton et al. (1839); Houghton et al, (1940); U. S. Army Engineers (1904). LAKE ERIE WATER CHEMISTRY SINCE 1854 As a part of the program of assembling as complete as possible a background of information on the condition of the Lake Erie aquatic environment, search was made for chemical analyses of Lake Erie water. Suitable data of this type are not abundant but enough analyses were found to allow us to reconstruct the trend lines of chemical composition for the period 1854 to 1956. The data, together with indications of the source papers, are given in Table X. The results clearly show a change in the chemical constituents of the lake water since 1854. They are summarized in about fifty-year intervals by the three major sets of analyses: 1854 1906-07 1956 Alkalinity 98,* 90. Silica 5.0 5.9 1,5 Iron 359 0.07 0.1 Calcium 20. 31. 36. Magnesium 7.6 8.9 Sodium plus potassium 3.7 6.5 8i7 Carbonate 3.1 Bicarbonate 114. 152 * Sulphate 6.6 13. 23. Nitrate 0.3 0.4 Chloride 8.7 20. Total Solids 98.1 133. 171. All analyses in parts per million *Calculated by method of Palmer (1911). It should be remarked in passing that none of these analyses appear to be suspect, except that for silica in the two sets of earlier determinations. Older silica values in these and other analyses are materially higher than are obtained by modern methods. Other analyses in 1882, 1897, 1901, 1902, 1925, 1928, 1929, 1930, 1937 through 1948, 1948-49, and in 1950-52, while not complete analyses, do introduce 46

TABLE IX MONTHLY MEAN LAKE LEVELS, LAKE ERIE, ABOVE MEAN TIDE AT NEW YORK, FEET. CLEVELAND GAUGE BACK THROUGH 1855. Underlining indicates change of one digit. Month 1859 1858 1857 1856 1855 1854 1853 1852 1851 1850 1849 1848 1847 1846 1845 1844 1843 1842 Jan 574.08 573.85 571.74 573.25 572.39 571-.0 571.06 572.76 Feb 573.86 573.45 571-77 572.85 572.08 571.51 570.72 Mar 574.27 573.48 572.52 572.14 572.12 572.03 570.64 Apr 574.84 573.59 573.01 572.43 572.15 571.01 572.61 May 574.72 573.85 573250 572.97 572.95 572.56 572.78 572.23 572.57 571.98 573.07 572.98 572.73 571.27 June 574.69 575.21 573.88 573.35 573.23 573.09 572.11 572.27 July 574.75 575.16 573.97 573. 38 573.73 573.16 572.73 572.22 Aug 574.45 575.07 573.93 573.23 573 95 573.17 573.17 572.05 572.48 Sept 573.85 574.51 573.68 572.98 573.30 572.84 572.86 572.16 Oct 574.06 574.41 573.22 572.32 573. 54 572.70 572.63 572,71 572.27, 571.93 Nov 573.88 573.99 573.76 572.20 573.61 573.00 571-39 571.64 Dec 573.68 574.09 573.76 572.49 573.89 572.42 571.49 571.31 Month 1841 1840 1839 1838 1837 1836 1835 1834 1833 1832 1831 1830 1829 1828 1827 1826 1825 1824 Jan 572.39 570.37 571.51 572.02 Feb 572.39 Mar 572.36 569.86 Apr 572.75 571.79 May 573.27 571.86 573.27 574.36 June 573.01 571.94 573.60 575.03 572.53 572.47 572.34 572.59 571.94 572.28 571.86 571.86 571.86 572.28 571.11 July 572.57 572.15 573.85 575.11 Aug 572.07 573.90 574.55 573.22 572.72 571.72 571.72 Sept 571.52 571.60 573.10 574.14 571.61 571.84 Oct 570.64 571.49 574.07 573.75 Nov 570.56 571.30 572.29 572.29 Dec 571.68 571.07 573.15 Month 1823 1822 1821 1820 1819 1818 1817 1816 1815 1814 1813 1812 181 1810., 1809 1808 1807 1806 Jan lake Feb 568.44 low Mar 568.25 Apr 566.50 May June 570.11 569.02 569.78 571.86 570.11 570.75 568.25 567.25 566.33 566.00 566.00 July 569.36 571.86 Aug 570.07 573511 Sept Oct Nov Dec 570.36 Month 1800-1802 1798 1796 1702 Jan lake Lake very low, Detroit Feb rising possibly lowest settled Mar of all; beach by Apr never been so French May broad and conJune 571.11 tinuous since. July Settlers enterAug ing Ohio drove Sept teams on beach Oct most of way Nov from Buffalo to Dec Cleveland. 47

TABLE X CHEMICAL ANALYSES, LAKE ERIE WATER, PPM Analyses of 1854 and 1882 have been reduced from hypothetical combinations. Detroit River Ashtabula Off Erie Buffalo Off Ashtabula Off Conneaut Off Fairport Cleveland 1854a 1882a 18978 1901b 1901-03C 1906-07d 31 Jan. 1925e 31 Jan. 1925e 4 F 1925e 1928r 1929f 1930 l937f Alkalinity 98.8 98.* 105 75 (?) 105. Silica 5.0 7.2 5.9 Iron 3.9 o.07 0.61 0.64 0.79 0.37 Calcium 20. 26.4 23. 31. Magne sium 7.4 7.6 9.3 9.5 Sodium plus potassium 3.7 6.5 Carbonate 3.1 Bicarbonate 110. 114. Sulphate 6.6 4.6 13. Nitrate 0.1 0.09 0.3 O. 06 0.21 0.04 Chloride 7.5 5.1 6.4 8.7 15. 7. 42. Total solids 98.1 117.1 108. 159. 144. 133. 160. 140. 255. Cleveland Port Stanley, Ont. Lorain Erie 1938f 1939f 1940f 1941f 1942f 1943f 1944f 1946f 1947f 1948f 1948-49g 1950-52h 19561 Alkalinity 91.* 90. Silica 1.3 1.9 1.5 Iron 0.44 0.42 0.34 0.29 0.42 0.02 0.04 0.1 Calcium 38. 36. 36. Magnesium 9.2 9.1 8.6 8.7 8.8 8.7 9.1 8.9 8.5 8.6 7.7 8.5 8.9 Sodium plus potassium 9.2 9.5 8.7 Carbonate 0.4 8.0 Bicarbonate 107. 113. 152.** Sulphate 42.4 25. 23. Nitrate 1.14 1.2 0.4 Chloride 17.8 18. 20. Total solids 174. 165. 171. *Calculated or back-calculated (**) by method of Palmer (1911). aFrom U. S. Geol. Surv. Water-Supply Paper No. 31. bAshtabula, low pressure data, pp. 164-5 in Foulk (1925). CFrom U. S. Geol. Surv. Water-Supply and Irrigation Paper No. 161. dFrom U. S. Geol. Surv. Water-Supply Paper 2536, also in U. S. Geol. Surv., Prof. Paper 135. epersonal communicatibn, U. S. Engineer Office, Buffalo, N. Y., to U. S. Fish and Wildlife Service, Ann Arbor. Ammonia fractions, nitrite, BOD also given. Single samples only. Data of the Division and Baldwin water plants at Cleveland, collected oy the present contract. Yearly averages derived from monthly averages at the plants. gAverage of 12 monthly samples throughout the year, from Thomas (1954), pp. 26-29. hAverage of numerous samples throughout the year at the Lorain water plant, from Lake Erie Pollution Survey. Supplement (1953). iFrom Ninetieth Annual Report of the City of Erie. 48

into the chemical history sufficient detail to indicate that nearly all the chemical parameters exhibited a notable depression in the period centered about 1897-1902. Since 1902 steady gains have been shown by total solids, calcium, sulphate, chloride, sodium plus potassium, and carbonate; in the same period decreases are shown by bicarbonate and silica; while magnesium, iron, and nitrate have shown little change. Detailed analyses of numerous samples spread well throughout the year are available from Buffalo, N. Y. in 1906-07, Port Stanley, Ontario in 1948-49, Lorain, Ohio, in 1950-52 and from Erie, Pennsylvania in 1956; that from Port Stanley, Ontario is not quite comparable with the others as it involves the water of the northern part of the central basin, From Lorain 1950-52 was obtained the ratio of alkalinity to each of the other chemical constituents. These ratios were applied to the monthly alkalinity values obtained at the Lorain and Erie water plants to obtain approximate chemical compositions of the western and central basin waters during the period of record of these two plants. These monthly chemical estimates and annual means derived from them are given in Appendix I. THE METROPOLITAN POPULATION INDEX It is almost axiomatic that the quantities of foreign material entering a body of water are in proportion to the level of human population around that water body. The materials that enter Lake Erie as direct and indirect effects of man's presence can be represented in a rough and qualitative way by the human population in the metropolitan belt that surrounds the west and south sides of the lake. To this end the sum of populations of Detroit, Toledo, Cleveland, Erie, and Buffalo have been taken as an index of the probable magnitude of man's total effects on Lake Erie. For comparative purposes the population of metropolitan Chicago is also included. Census Erie Index Chicago 1950 3,778,927 3,620,962 1940 3,476,993 3,396,808 1930 3,448,852 3,376,438 1920 2,633,830 2,701,705 1910 1,685,166 2,185,283 1900 1,204,414 1,698,575 1890 844, 961 1,099,850 1880 509,494 503,185 1870 337,350 298,977 1860 193,352 112,172 1850 90,001o 29 963 1840 38,020 4,470 1830 13,431 1820 4,758 49

From these figures it is apparent that Lake Erie between 1820 and 1890 had a heavier population-pressure than the city of Chicago could have provided. From 1890 through 1920 Chicago contained somewhat more people than were located in the metropolitan belt of Lake Erie, but since 1930 Lake Erie has been subject to a larger metropolitan population than that of Chicago. When it is remembered that Lake Erie contains about 99 cubic miles of water while Lake Michigan contains 1120 cubic miles, it becomes reasonable to expect that the smaller lake may be reflecting in its chemistry the effects of human population-pressure. Except for the plant-nutrient chemicals (silica, nitrate, and possibly iron) and alkalinity, the chemical constituents of the lake have increased very significantly in the past century. INDICATIONS OF BIOLOGICAL CHANGE Several indications of biological change in Lake Erie can be found in the literature, The earliest found was reported by Mills (1882) and Smith (1882), Both of these authors mention a decrease in the numbers of the diatom Stephanodiscus niagarae in 1878; previously this form had been the most prevalent diatom in Lake Erie, The decline of this form, plus the discovery of Actinocyclus niagarae (Smith, 1878) and Rhizosolenia gracilis (Smith, 1882), fresh-water members of two predominantly marine genera of diatoms, represent changes in the phytoplankton of Lake Erie during the period 1877-1882. Actinocyclus niagarae later disappeared; it was last recorded in the winter of 1881-82 (Vorce, 1881), Snow (1903) stated that from 1889 to 1900 Kirchneriella obesa (Chlorophyceae) declined from one of the most common plankters to a form that was only occasionally recorded. During this same period, in 1899, Oocystis borgei (Chlorophyceae) first appeared and became a relatively abundant form. A year later, in 1900, this plankter had decreased and was found only in small numbers. Hintz (1955) reported that Cyclotella melosiroides (alga), which was not present in Lake Erie prior to 1950, had increased by 1953 until it was a major form, He also recorded that Stephanodiscus spo decreased during the period 1950-53. In 1953, thermal stratification and resultant oxygen depletion in the Bass Islands region apparently resulted in heavy destruction of the may-fly Hexagenia (Britt, 1955a). In 1954 it appeared that the Hexagenia population would become reestablished (Britt, 1955b), but according to more recent studies it has apparently been unsuccessful (A. M. Beeton, Uo S. Fish and Wildlife Service, personal communication). At present larvae of the midge, Chironomous, compose the bulk of the benthos in the Bass Islands region and the once prevalent Hexagenia are relatively scarce. In 1955 a new diatom Stephanodiscus hantzscii appeared for the first time in the raw water of the South District Filtration Plant in Chicago, Illinois, 50

which obtains its water directly from Lake Michigan (J. R. Baylis, personal communication). This plankter had, by 1957, established itself as a major component of the phytoplankton, reaching population densities of 5,000 to 10,000 cells per 100 mlo Further indications of biological change in Lake Erie can be found in the fluctuations of certain commercially valuable fish populations. Probably the most striking example of such fluctuations was the sudden decline of the cisco, Coregonus artedi, in 1925 (International Board of Inquiry for Great Lakes Fisheries, 1943). In 1924 the total production of this fishery, in both United States and Canadian waters, was 32,200,633 pounds; in 1925 it was 5,756,600 pounds, and by 1929 had declined to 488,874- pounds. It has never since approximated its former abundance. Intermittent records from 1879 to 1913, and yearly records from 1913 to the present indicate that prior to 1925 the catch had never fallen below 10,500,000 pounds, and in most years was in excess of 20,000,000 pounds. Such a sudden drop in numbers suggests the occurrence of a catastrophic event or a series of near-catastrophic events which would have acted to cause the death of possibly entire year classes. Analyses of the history of Lake Erie water chemistry indicate no such change or changes in the lake water; a perusal of the meteorology from 1880 to the present brings to light one particularly interesting point, namely, that March 1921 was the warmest March on record up to that time; in fact, only twice since that time has an equally high average temperature for that month been recorded, in 1946 and 1947. John and Hasler (1956) have shown that a water temperature increase of 10C during the last month of incubation of the cisco will advance the time of hatching seven days, and that ciscos hatched in water of temperatures between four and eleven degrees will be able to survive in the absence of food no longer than eighteen days. Since larval ciscos are zooplankton feeders, it is conceivable that an early hatch in 1921 could have preceded the time of the spring zooplankton pulse, resulting in the starvation of most of that year class. The loss of the reproductive potential of this year class could have, in turn, contributed to the decline of the fishery in 1925. Further work on this problem is necessary, and the ideas outlined here represent only preliminary considerations. In summary, the literature indicates several periods of biological change: 1877-1882. Change in phytoplankton in Lake Erie 1889-1900. Change in phytoplankton in Lake Erie 19250 Decline in cisco in Lake Erie 1950-1953. Change in phytoplankton in Lake Erie 1953-1957. Change in composition of bottom fauna in Bass Islands 1955-1957. Change in phytoplankton in southern Lake Michigan. 51

SUMMARY OF MAJOR PAST EVENTS The preceding sections have presented summaries of history of rainfall, lake levels, water chemistry, and biological changes in Lake Erie. These materials are given as they stand in our present state of knowledge. That they will be changed as additional information comes to light must be understood. As a summary, Table XI has been prepared to point out the major events on record in the present status of the several categories. No attempt has been made to correlate simultaneous events on a cause and effect basis, and such is not implied in this summation, Meaningful correlations may well exist; they remain as priority topics for continued investigation. CONCLUSION The results and techniques presented in this report have come from the Lake Erie pilot study on the usefulness of the data being accumulated by municipal and industrial users of lake water. They show that these data have a very material potential in both understanding past events in the lake and in "watching" the lake for the development of trends in the future. The pilot study, and the studies of past aquatic conditions that have accompanied it, have made available a substantial amount of new information and techniques that have promise of aiding in the understanding of past fluctuations in the commercial fisheries as well contributing to our understanding of the more academic problem of the eutrophication of lakes. There are still a number of facets of the past conditions of the aquatic environment that have yet to be studied. Among these may be mentioned the assembly of a record of past unusually severe or unusually mild meteorological conditions and their probable effects on the lake, further search for biological indications of changing or changed conditions in the water, and the development of a set of criteria by which the data from representative water-user installations can be watched for the development of trends favorable or unfavorable for commercially important fish species. Because the studies now completed and those outlined, in part, above are certain to provide a materially increased body of information pertinent to the understanding and management of the commercial fisheries, and because these studies may result in important break-throughs in the understanding of past fishery fluctuations, the investigators propose that Phase III of the contract outline (the collection of the useful data from collateral data sources) be abandoned in favor of a continuation of the types of study developed by the pilot program just completed. 52

TABLE XI TENITATIVE MAJOR-EVENTS STiWARY, 1800-1958 Lake Year Rainfall Lake Water Chemistry Bioloagy Air Tem.perature Level 1801-02 low 1809-10 low 1810-14 high 1815-16 high 1815-19 low 1819-20 low 1]819-37 high 1838 high 1838-41 low 1840 low 1842 high 1843 low 1846 low 1848-50 high 1854 Detroit River: Calcium low Total solids low 1858-59 high 1860 low 1860-62 high 1862 high 1863-65 low 1866 high 1867 low 1871-72 low 1872 low 1875 hi h 1874-75 low 1876 high high 1878 high Actinocycl'us niaarae discovered Stephanodiscus niagarae decreased 1880 h i gh 1882 Detroit River: Rhizosolenia gracilis discovered Calcium up Actinocyclus disappeared Total solids up 1882-87 high 1883 high 1884 low 1885 high 1886-89 low 1889-1900 Kirchneriella obesa declined 1890 high 1890-93 high 1891 low 1894-1901 low 1895-96 low 1897 Detroit River: Calcium low Total solids low 1899 Oocystls borgei appeared 1900 Oocystis borgei declined 1901 low 1902-03 high 1904-08 low 1909 high 1910 low 1911 low 1912 low 1913 high high 1914-16 low 1915 low 1917 high 1918 low 1918-25 low 1921 Warmest March on record 1923 low 1925 cisco decline 1925-26 low Ashtabula: Chlorides up 1926 high 1928 low 1929 high 1929-30 high 1930-356 low 1931- 36 low 1937 high 1938-39 low 1940 high 1941 low 1942 high 1945-47 high 1944 high 1945 high 1946 low Warmn March equals record 1947 Warm March equals record 1947-48 high 1949 low 1950-51 high Cyclotella melosiroides appeared 1950 Stephanodiscus sp. declined 1950-53 1952 high 1952-55 low Cyclotella melosiroides a major form 1953 19553 Hexagenia decline 1954 high 1955 low Stephanodiscus hantzscii appeared in southern L. Michigan 1956 Erie, Pa.: Nitrate up Alkalinity down Chlorides uF Total solids up 1956-57 high 1958 low 55

A further factor in making this recommendation is the demonstration, in the present report, that not all onshore data sources are representative stations. Before the useful data could be collected from all sources around the several lakes, it would be necessary to eliminate all the unrepresentative stations.

LITERATURE CITED Ayers, J. C. (unpublished), 1958. Studies of the wind and current regimes in the Point Mouillee-Sto~ny Point region of western Lake Erie. Ayers, J. C., D. C. Chandler, G. H. Lauff, C. F. Powers and E. B. Henson, 1958. Currents and water masses of Lake Michigan. Great Lakes Research Institute, Publication No. 3. University of Michigan, Ann Arbor, Mich., iii and 169 pp, 52 figs., 16 tables. Boughner, C. C. and M. K. Thomas, 1948. Climatic summaries for selected meteorological stations in Canada. Meteorological Division, Canadian Department of Transport. Britt, N. W., 1955. Hexagenia (Ephemeroptera) population recovery in western Lake Erie following the 1953 catastrophe. Ecology, 36 (3) 520-522. Britt, N. W., 1955. Stratification in western Lake Erie in summer of 1953: effects on the Hexagenia (Ephemeroptera) population. Ecology, 36 (2) 239244. Chandler, D. C., 1940. Limnological studies of western Lake Erie. I. Plankton and certain physical-chemical data of the Bass Islands region, from September, 1938, to November, 1939. Ohio Jour. Science, 40 (6) 291-336. Chandler, D. C., 1942. Limnological studies of western Lake Erie. II. Light penetration and its relation to turbidity. Ecology, 23 (1) 41-52. Chandler, D. C., 1942. Limnological studies of western Lake Erie. III. Phytoplankton and physical-chemical data from November, 1939, to November, 1940. Ohio Jour. Science, 42 (1) 24-44. Chandler, D. C., 1944. Limnological studies of western Lake Erie. IV. Relation of limnological and climatic factors to the phytoplankton of 1941. Trans. Amer. Micros. Soc., 63 (3) 203-236. Chandler, D. C. and 0. B. Weeks, 1945. Limnological studies of western Lake Erie. V. Relation of limnological and meteorological conditions to the production of phytoplankton in 1942. Ecol. Monogr., 15 (4) 436-457. Clarke, F. W., 1924. The composition of the river and lake waters of the U. S. U. S. Geol. Surv., Prof. Paper 135, 99 PP. Gov't. Printing Office, Washington, D. C. 55

Cooperman, A., G. Cry and H. Sumner, 1959. Climatology and weather services of the St. Lawrence seaway and Great Lakes. Technical Paper No. 35, U. S. Weather Bureau, Washington, D. C. 75 pp, 33 figs., 38 tables. Dole, R. B., 1909. The quality of surface waters in the United States. Part 1. Analyses of waters east of the one hundredth meridian. U. S. Geol. Surv., Water-supply Paper 236. Gov't. Printing Office, Washington, D. C. City of Erie, Pa., 1957? Ninetieth Annual Report of the City of Erie -- Bureau of Water, Department of Public Affairs, Erie, Pa. for the year ending December 31, 1956. McCarty Printing Corp., Erie, Pa. 61 pp, many unnumbered tables. Fell, G. E., 1910. The currents of the easterly end of Lake Erie and head of the Niagara River. Jour. Amer. Med. Assoc., 55: p 828. Fish, C. J. (unpublished). Results of the cooperative surveys of Lake Erie in 1929. Foster, J. W. and J. D. Whitney, 1851. Report on the Geology of the Lake Superior Land District. Part II. The iron region together with the general geology. Exec. Doc. No. 4, U. S. Senate, Special Session, March 1851. Washington. 1851. xvi and 406 pp, 38 figs., 35 plates. Foulk, C. W., 1925. Industrial water supplies of Ohio. Geological Survey of Ohio, 4th Series, Bull. 29. Columbus, Ohio. 406 pp. 20 tables. Gilbert, G. K., 1898. Recent earth movement in the Great Lakes region. 18th Annual Report, U. S. Geol. Surv., Pt. II. pp 601-647. Harrington, M. W., 1894. Currents of the Great Lakes, as deduced from the movements of bottle papers during the seasons of 1892 and 1893. U. S. Dept. of Agriculture, Weather Bureau, Bulletin B. U. S. Weather Bureau, Washington, D. C. 6 pp, 5 charts. Hintz, W. J., 1955. Variations in populations and cell dimensions of phytoplankton in the island region of Lake Erie. Ohio Jour. Science, 55 (5) 271278. Horton, Robert E. and C. E. Grunsky, 1927. Report of the Engineering Board of Review of the Sanitary District of Chicago on the lake lowering controversy and a program of remedial measures. Part III - Appendix II. Hydrology of the Great Lakes. The Sanitary District of Chicago, Chicago, Ill. xviii and 432 pp, 142 tables, 73 figs. Houghton, D. and others, 1839. Second Annual Report of the State Geologist of the State of Michigan. J. S. Bagg, Detroit, Printer to the State. 1839. 39 and 120 pp, a few unnumbered tables. In Michigan State Geologist Annual Report 1-7, 1837-44. Also Mich. Senate Doc. No. 23.

Houghton, D. and others, 1840. Third Annual Report of the State Geologist. State of Michigan, House of Representatives, Document No. 8. 1840. In Michigan State Geologist Annual Report 1-7, 1837-44. 124 pp, 1 map, a few unnumbered tables. Houghton, D. and others, 1841. Fourth Annual Report of the State Geologist. State of Michigan, Senate Document No. 16. In Michigan State Geologist Annual Report 1-7, 1837-44. 184 pp, a few unnumbered tables. Hunt, I. A., 1958. Winds, wind set-ups, and seiches on Lake Erie. Paper given at Second National Conference on Applied Meteorology, Ann Arbor, Michigan. International Board of Inquiry for Great Lakes Fisheries, Report and Supplement. Gov't. Printing Office, Washington, D. C. 1943. 213 pp. John, K. R. and A. D. Hasler, 1956. Observations on some factors affecting the hatching of eggs and the survival of young shallow-water cisco, Leucichthys artedi Le Sueur, in Lake Mendota, Wisconsin. Limnol. and Oceanogr., 1 (3) 176-194. Johnson, J. H., 1958. Surface-current studies of Saginaw Bay and Lake Huron, 1956. U. S. Dept. of Interior, Fish and Wildlife Service, Special Scientific Report -- Fisheries No. 267. Washington, D. C. 84 pp, 72 figs., 7 tables. Lane, A. C., 1899. Lower Michigan mineral waters. U. S. Geol. Surv., Watersupply Paper No. 31. Gov't. Printing Office, Washington, D. C. Lewis, S. J., 1906. Quality of water in the upper Ohio River basin and at Erie, Pa. U. S. Geol. Surv., Water-supply and Irrigation Paper No. 161. Gov't. Printing Office, Washington, D. C. 114 pp, many unnumbered tables. McLaughlin, A. J., 1911. Sewage pollution of interstate and international waters with special reference to the spread of typhoid fever. 1. Lake Erie and the Niagara River. U. S. Hygenic Lab. Bull. No. 77, 169 pp. Millar, F. G., 1952. Surface temperatures of the Great Lakes. Jour. Fish. Res. Board Canada 9(7) 329-376. Mills, H., 1882. Microscopic organisms in the Buffalo water-supply and in Niagara River. Proc. Amer. Soc. Micros., 5th Annual Meeting, pp 165-175. State of Ohio, 1953. Lake Erie Pollution Survey, Supplement. State of Ohio, Department of Natural Resources, Division of Water. Columbus, Ohio. ii and 125 pp, 39 tables. Olson, F. C. W., 1951. The currents of western Lake Erie. Doctoral Thesis, Ohio State University, Columbus, Ohio. 57

Palmer, C., 1911. The geochemical interpretation of water analyses. U.S.G.S. Bull. 479, Gov't. Printing Office, Washington, D. C. 31 pp, 5 tables. Parmenter, R., 1929. Hydrography of Lake Erie. In Preliminary report on the cooperative survey of Lake Erie -- season of 1928. Bull. Buffalo Soc. Nat. Hist., 14(3): 25-50. Powers, C. F., D. L. Jones, and J. C. Ayers, 1958. Exploration of collateral data potentially applicable to Great Lakes hydrography and fisheries. Phase I. Final Report, U. S. Fish and Wildlife Service Contract 14-19-008-9381. Great Lakes Research Institute, University of Michigan, Ann Arbor, Mich. 159 pp, 9 figs., 5 tables. Ruschmeyer, O. R., T. A. Olson and H. M. Bosch, 1958. Water movements and temperatures of western Lake Superior. School of Public Health, University of Minnesota, Minneapolis, Minn. 65 and 21 pp, 46 figs., 11 tables. Smith, H. M., 1878. Description of a new species of diatoms. Amer. Quart. Micros. Jour., 1: 12-18, 1 plate. Smith, H. M., 1882, Rhizosolenia gracilis, n. sp. Proc. Amer. Soc. Micr., 5: 177-178. Snow, J. W., 1903. The plankton algae of Lake Erie, with special reference to the Chlorophyceae. Bull. U. S. Fish. Comm. (1902) 22: 369-394, 1904 Doc. (529) issued August 4, 1903. Thomas, J. F. J., 1954. Industrial water resources of Canada. Upper St. Lawrence River -Central Great Lakes Drainage Basin in Canada. Water Survey Report No. 3. Canada Department of Mines and Technical Surveys, Mines Branch, Industrial Minerals Division. Ottawa, Canada. 212 pp, 9 figs., 6 tables. U. S. Army Engineers, 1869. Report of the Chief of Engineers to the Secretary of War for the year 1868. Report of the Secretary of War. Part II. Gov't Printing Office, Washington, D. C. 1869. 1200 pp, many unnumbered tables. U. S. Army Engineers, 1870. Annual report of the Chief of Engineers to the Secretary of War for the year 1870. Gov't.Printing Office, Washington, D. C. 1870. 631 pp, a few drawings, many unnumbered tables. U. S. Army Engineers, 1904. Annual reports of the War Department for the fiscal year ended June 30, 1904. Vol. VIII. Report of the Chief of Engineers, Pt. 4. pp 4093-4105. House of Representatives Doc. No. 2, 58th Congress, 3rd Session. Gov't. Printing Office, Washington, D. C. U. S. Dept. of Interior, U. S. Fish and Wildlife Service, Bureau of Commercial Fisheries, Great Lakes Fishery Investigations. 1958. Cruise Reports, M/ V CISCO. Cruises III, VII, XI. 58

U. S. Dept. of Interior, Geological Survey Water Supply Papers. Surface water supply of the United States, St. Lawrence River Basin. (For the years indicated) Vorce, C. M., 1881. Forms observed in water of Lake Erie. Proc. Amer. Soc. Micr., 4: 50-60. Verber, J. L., 1955. Rotational water movements in western Lake Erie. Proc. Intern. Assoc. Theoret. Appl. Limnol., 12: 97-104. Wright, S., L. H. Tiffany and W. M. Tidd, 1955. Limnological survey of western Lake Erie. U. S. Dept. of Interior, Fish and Wildlife Service, Special Sci. Report - Fisheries No. 139, v and 341 pp, 23 figs., U. S. Gov't. Printing Office, Washington, D. C.

APPENDIX I VALUES BASED ON TOTAL ALKALINITY Part 1. Station at Lorain, Ohio

Year 1910 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Batio* Temp. (Avon) Temp. (Lorain) Total solids 121 129 125 147 154 172 174 179 170 148 168 159 154 Nitrate.88.94.90 1.07 1.12 1.25 1.27 1.51 1.24 1.08 1.2 1.16 1.12.02 Fluoride.07.08.07.09.09.10.11.11.10.09.10.10.09.0011 Chloride 13.3 14.1 15.5 16.0 16.8 18.8 19.o 19.6 18.6 16.2 18.4 17.4 16.8.198 Sulphate 18.4 19.5 18.7 22.5 23.4 26.1 26.4 27.2 25.9 22.5 25.6 24.2 25.4.275 Bicarbonate 83 88 84 100 105 118 119 125 117 102 115 109 105 Sodium plus 7.0 7.4 7.1 8.4 8.8 9.9 10.0 10.5 9.7 8.5 9.7 9.2 8.8.104 potassium Magnesium 6.2 6.6 6.5 7.5 7.9 8.8 8.9 9.2 8.7 7.6 8.6 8.2 7.9.095 Calcium 26.5 28.0 26.9 -32.0 33.6 37.5 37.9 39.1 37.1 32.4 36.7 34.8 55.75 595 Iron.05.05.05.05.05.04.04.o4 o04.05.4 04.05.0004 Silica 1.4 1.5 1.4 1.7 1.8 2.0 2.0 2.1 2.0 1.7 2.0 1.8 1.8.021 Alkalinity 67 71 68 81 85 95 96 99 94 82 93 88 84.9 1.0 *The "ratio" values indicated are the ratio of the parameter in question to alkalinity, i.e., "ratio" parameter/alkalinity. These values apply to years 1910-1957, pages 62-109.

Year 1911 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp. (Lorain) Total solids 138 150 163 159 167 168 170 168 150 145 147 143 156 Nitrate 1.00 1.10 1.19 1.16 1.21 1.23 1.24 1.23 1.10 1.06 1.07 1,04 1.13 Fluoride.08.09.10.10.10.10.10.10.09.09.09.09.09 Chloride 15.0 16.4 17.8 17.4 18.2 18.4 18.6 18.4 16.4 15.8 16.0 15.6 17.0 Sulphate 20.9 22.8 24.7 24.2 25.3 25.6 25.9 25.6 22.8 22.0 22.3 21.7 23.6 \IN Bicarbonate 94 103 112 109 114 115 117 115 103 99 100 98 107 Sodium plus 7.9 8.6 9.4 9.2 9.6 9.7 9.8 9.7 8.6 8.3 8.4 8.2 8.9 potassium Magnesium 7.1 7.7 8.4 8.2 8.6 8.6 8.7 8.6 7.7 7.4 7.5 7.3 8.0 Calcium 30.0 32.8 35.5 34.8 36.3 36.7 37.1 36.7 32.8 31.6 32.0 31.2 34.0 Iron.03.03.04.04.04.04.04.04.03.03.03.03 Silica 1.6 1.7 1.9 1.8 1.9 2.0 2.0 2.0 1.7 1.7 1.7 1.7 1.8 Alkalinity 76 83 90 88 92 93 94 93 83 80 81 79 86.0

Year 1912 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp (Avon) Temp. (Lorain) Total solids 145 130 110 138 152 168 170 172 170 172 172 172 156 Nitrate 1.06.95.81 1.00 1.11 1.23 1.24 1 25 1.24 1.25 1.25 1.25 1.13 Fluoride.09.08.07.08.09.10.10 10 10.10.10.10.09 Chloride 15o8 14.3 12.1 15.0 16.6 18.4 18.6 18.8 18.6 18.8 18.8 18.8 17.0 Sulphate 22.0 19.8 16.8 20.9 23.1 25.6 25.9 26.1 25.9 26.1 26.1 26.1 23.7 Bicarbonate 99 89 76 94 104 115 117 118 117 118 118 118 107 Sodium plus 8.3 7.5 6.3 7.9 8.7 9.7 9.8 9.9 9.8 9.9 9.9 9.9 9.0 potassium Magnesium 7.4 6.7 5.7 7.1 7o8 8.6 8.7 8.8 8.7 8.8 8.8 8.8 8,0 Calcium 31.6 28.4 24.1 30.0 33o2 36.7 37.1 37.5 37.1 37.5 37,5 37.5 34.0 Iron.03.03.02.03.03.04.04.04.04.04.04.04.03 Silica 1.7 1.5 1.3 1.6 1.8 2.0 2.0 2.0 2.0 2.0 2.0 2.0 1.8 Alkalinity 80 72 61 76 84 93 94 95 94 95 95 95 86.2

YIear 1913 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp. (Lorain) Total solids 154 172 148 156 163 167 170 177 177 174 170 168 166 Nitrate 1.12 1.25 1.08 1.14 1.19 1.21 1.24 1.29 1.29 1.27 1.24 1.23 121 Fluoride.09 ol0.09.09.10.10.10.11.11.11.10.10.10 Chloride 16.8 18.8 16.2 17.0 17.8 18.2 18.6 19.4 19.4 19.0 18.6 18.4 18.2 Sulphate 23.4 26.1 22.5 23.7 24.7 25.3 25.9 26.9 26.9 26.4 25.9 25.6 25.3 \" v Bicarbonate 105 118 102 107 112 114 117 122 122 119 117 115 114 Sodium plus 8.8 9.9 8.5 8.9 9.4 9.6 9.8 10.2 10.2 10.0 9.8 9.7 9.6 potassium Magnesium 7.9 8.8 7.6 8.0 8.4 8.6 8.7 9.1 9.1 8.9 8.7 8.6 8.5 Calcium 33.6 37.5 32.4 34.0 35.5 36.3 37.1 38.7 38.7 37.9 37.1 36.7 36.3 Iron.03.04.03.03.04.04.04 o 04.04.04.04 04.04 Silica 1.8 2.0 1.7 1.8 1.9 1.9 2.0 2.1 2.1 2.0 2.0 2.0 1.9 Alkalinity 85 95 82 86 90 92 94 98 98 96 94 93 91.9

Year 1914 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp. (Lorain) Total solids 170 168 165 167 157 172 177 179 177 176 176 174 172 Nitrate 1.24 1.23 1.20 1.21 1.15 1.25 1.29 131 1.29 1.28 1.28 1.27 25 Fluoride.10.10.10.10.10.10.11.11.11.11.11.11. Chloride 18.6 18.4 18.0 18.2 17.2 18.8 19o4 19.6 19.4 19.2 19.2 19.0 18 8 Sulphate 25.9 25.6 25.0 25.3 23.9 26.1 26.9 27.2 26.9 26.7 26.7 26.4 260 Bicarbonate 117 115 113 114 108 118 122 123 122 120 120 119 118 Sodium plus 9.8 9.7 9.5 9.6 9.0 9.9 10.2 10.3 10.2 10.1 10.1 10.0 9.9 potassium Magnesium 8.7 8.6 8.5 8.6 8.1 8.8 91 9.2 9.1 9.0 9.0 8.9 88 Calcium 37.1 36.7 35.9 36.3 34.4 37.5 38.7 39.1 38.7 38.3 38.3 379 37.4 Iron.04.04.04.04.03.04 o04.04.04.04 o04.04.04 Silica 2.0 2.0 1.9 1.9 1.8 2.0 2l.1 2.1 2.1 2.0 2.0 2.0 2.0 Alkalinity 94 93 91 92 87 95 98 99 98 97 97 96 948

Year 1915 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp. (Lorain) Total solids 172 163 170 172 170 176 172 174 176 176 176 176 173 Nitrate 1.25 1.19 1.24 1.25 1.24 1.28 1.25 1.27 1.28 1.28 1.28 1.28 1.26 Fluoride.10.10.10.10.10.11.10.11.11.11.11.10 Chloride 18.8 17.8 18.6 18.8 18.6 19.2 18.8 19.0 19.2 19.2 19.2 19.2 18.9 Sulphate 26.1 24.7 25.9 26.1 25.9 26.7 26.1 26.4 26.7 26.7 26.7 26.7 26.2 Bicarbonate 118 112 117 118 117 120 118 119 120 120 120 120 118 Sodium plus 9.9 9.4 9.8 9.9 9.8 10.1 9.9 10.0.1 101 10.1 10.1 10.1 9.9 potassium Magnesium 8.8 8.4 8.7 8.8 8.7 8.7 8.8 8.9 9.0 9.0 9.0 9.0 8.8 Calcium 37.5 35.5 37.1 37.5 37.1 38.3 37.5 37.9 38.3 38.3 38.3 38.3 37.6 Iron.04.04.04.04.04.04.04.04.04.04.04.04.04 Silica 2.0 1.9 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Alkalinity 95 90 94 95 94 97 95 96 97 97 97 97 95.3

Year 1916 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp. (Lorain) Total solids 161 172 176 174 174 179 181 181 179 176 174 172 175 Nitrate 1.17 1.25 1.28 1.27 1.27 1.31 1.32 1.32 1.31 1.28 1.27 1.25 1.28 Fluoride.10.10.11.11.11.11.11.11.11.11.11.10.11 Chloride 17.6 18.8 19.2 19.0 19.0 19.6 19.8 19.8 19.6 19.2 19.0 18.8 19.1 Sulphate 24.5 26.1 26.7 26.4 26.4 27.2 27.5 27.5 27.2 26.7 26.4 26.1 26.6 0c Bicarbonate 110 118 120 119 119 123 124 124 123 120 119 118 120 Sodium plus 9.3 9.9 10.1 10.0 10.0 10.3 10.4 10.4 10.3 10.1 10.0 9.9 10.1 potassium Magnesium 8.3 8.8 9.0 8.9 8.9 9.2 9.3 9.3 9.2 9.0 8.9 8.8 9.0 Calcium 35.2 37.5 38.3 37.9 37.9 39.1 39.5 39.5 39.1 38.3 37.9 37.5 38.1 Iron.04.04.04.04.04.04.04.04.04.04.04.04.04 Silica 1.9 2.0 2.0 2.0 2.0 2.1 2.1 2.1 2.1 2.0 2.0 2.0 2.0 Alkalinity 89 95 97 96 96 99 100 100 99 97 96 95 96.6

Year 1917 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp. (Lorain) 22 23 20 12 7 Total solids 174 177 170 167 170 177 183 185 186 177 172 170 176 Nitrate 1.27 1.29 1.24 1.21 1.24 1.29 1.33 1.35 1.36 1.29 1.25 1.24 1.28 Fluoride.11.11.10.10.10.11.11.11.11.11.10.10.11 Chloride 19.0 19.4 18.6 18.2 18.6 19.4 20.0 20.2 20.4 19.4 18.8 18.6 19.2 Sulphate 26.4 26.9 25.9 25.3 25.9 26.9 27.8 28.0 28~3 26.9 26.1 25.9 26.7 Bicarbonate 119 122 117 114 117 122 125 126 128 122 118 117 121 Sodium plus 10.0 10.2 9.8 9.6 9.8 10.2 10.5 10.6 10.7 10.2 9,9 9.8 10.1 potassium Magnesium 8.9 9.1 8.7 8.6 8.7 9.1 9.4 9.5 9.6 9.1 8.8 8.7 9.0 Calcium 37.9 38.7 37.1 36.3 37.1 38.7 39.9 40.3 40.7 38.7 37.5 37.1 38.3 Iron.04.04.04.04.04 o04.04.04.04.04.04.04.04 Silica 2.0 2.1 2.0 1.9 2.0 2.1 2.1 2.1 2.2 2.1 2.0 2.0 2.0 Alkalinity 96 98 94 92 94 98 101 102 103 98 95 94 97-1

Year 1918 Jan. Feb. mar. Apr. May June Jul y Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp.(Lorain) 2 4 7 16 21 21 23 19 13 6 4 12.4 Total solids 176 138 159 165 167 163 116 174 174 176 176 172 167 Nitrate 1.28 1.00 1.16 1.20 1.21 1.19 1.20 1.27 1.27 1.28 1.28 1.25 1.22 Fluoride.11.08.10.10.10.10.10.11.11.11.11.10.10 Chloride 19.2 15.0 17.4 18.0 18.2 17.8 18.0 19. 0 19.0 19.2 19.2 18.8 18.2 Sulphate 26.7 20.9 24.2 25.0 25.3 24.7 25.0 26.4 26.4 26.7 26.7 26.1 25.3 o Bicarbonate 120 94 109 113 114 112 113 1ig 1ig 120 120 118 114 Sodium plus 10.1 7.9 9.2 9.5 9.6 9.4 9.5 10.0 10.0 10.1 10.1 9.9 9.6 potassium Magnesium 9.0 7.1 8.2 8.5 8.6 8.4 8.5 8.9 8.9 9,0 9.0 8.8 8.6 Calcium 38.3 30.0 34.8 35.9 36.3 35.5 35.9 37.9 37.9 38.3 38.3 37.5 36.4 Iron.04.03.04.04.04.o4.o4.04.04.04.04.o4.o4 Silica 2.0 1.6 1.8 1.9 1.9 1.9 1.9 2.0 2.0 2.0 2.0 2.0 1.9 Alkalinity 97 76 88 91 92 90 91 96 96 97 97 95 92.2

-yes.r 19!9 Yearly Fan. Feb. Mar~ Apr. May June July Aug. Sept. Oct. Nov. Dee. Av. Temp. (Avon) Temp. (Lorain) 3 2 3-6 5.5 12 18 23 23 21 16 10 2.5 11o 6 Total solids 174 176 170 176 177!81 188 177 192 179 172 170 178 Nitrate 1.27 1.28 1.24 l o28 1. 29 1.32 1.37 1. 29 1.40 1.o31 1.o25 1.o24 1.29 Fluoride.11.11.10.11.11.11.11.11 o12 o11.10.10.11 Chloride 19.0 19.2 18.6 19.2 19.4 19.8 20.6 19.4 21.0 19.6 18.8 18.6 19.4 Sulphate 26.4 26.7 25o9 26.7 26.9 27~.5 28.6 26.9 29.2 27. 2 26.1 25.9 27.0 Bicarbonate 119 120 117 120 122 124 129 122 131 123 118 117 122 Sodium plus 10o0 10o1 9.8 10ol 10.2 10.4 10.8 10.2 11.0 10.3 9.9 9.8 10.2 potassium Magnesium 8.9 9.0 8.7 9.0 9.1 9- 3 9- 7 9.1 9-.9 9-.2 8.8 8.7 9.1 Calclum 37.9 38~.3 37.1 38.3 38.7 39-.5 41.1 38.7 41.9 39.1 37.5 37.1 38.8 Iron, 04 o 04.04.04.04.04.04.04.04.04 o.04.04.04 Silicea 2o0 2.0 2.0 2.0 2.1 2.1 2~2 2.t 2.2 2.1 2.0 2.0 2.1 Alkalinity 96 97 94 97 98 100 104 98 106 99 95 94 98.2

Year 1920 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp.(Lorain) 1 1 2 6 11 17 21 21 21 16 8 4 108 Total solids 174 174 152 148 154 156 174 176 174 174 170 177 167 Nitrate 1.27 1.27 1.11 1.08 1.12 1.14 1.27 1.28 1.27 1.27 1.24 1.29 1.22 Fluoride.11.11.09.09.09.09.11.11.11.11.10.11 olO Chloride 19.0 19.0 16.6 16.2 16.8 17.0 19.0 19.2 19.0 19.0 18.6 19.4 18.2 Sulphate 26.4 26.4 23.1 22.5 23.4 23.7 26.4 26.7 26.4 26.4 25.9 26.9 25.4 Bicarbonate 119 119 104 102 105 107 119 120 119 119 117 122 114 Sodium plus 10.0 10.0 8.7 8.5 8.8 8.9 10o.0 10.1 10.0 10.0 9.8 10.2 9.6 potassium Magnesium 8.9 8.9 7.8 7.6 7.9 8.0 8.9 9.0 8.9 8.9 8.7 9.1 8.6 Calcium 37.9 37~9 33.2 32.4 33.6 34.0 37.9 38.3 37.9 37.9 37.1 38.7 36.4 Iron.04.04.03.03.03.03.04.04.04.04.04.04 04 Silica 2.0 2.0 1.8 1.7 1o8 1.8 2.0 2.0 2.0 2.0 2.0 2.1 1o9 Alkalinity 96 96 84 82 85 86 96 97 96 96 94 98 92

Year 1921 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temnp.(Lorain) ]. 1 6 9 12 20 25 23 21 16 9 11 12.3 Total solids 181 161 161 168 1711 1741 177 188 185 183 167 172 1741 Nitrate 1.32 1.17 1.17 1.23 1.27 1.27 1.29 1.37 1.35 1.33 1.21 1.25 1. 27 Fluoride.11.10.10.10.11.11.11.11.11.11.10.10.11 Chloride 19.8 17.6 17.6 18.11 19.0 19.0 19.11 20.6 20.2 20.0 18.2 18.8 19.0 Sulphate 27.5 211.5 211.5 25~.6 26.11 26.11 26.9 28.6 28.0 27.8 25.3 26~.l 26.5 -1 Bicarbonate 1211 110 110 115 119 119 122 129 126 125 1111 118 119 Sodium plus 10.4 9.3 9.3 9.7 10.0 10.0 10.2 10.8 10.6 10.5 9.6 9.9 10.0 potass iumn _Magnesium 9. 3 8.3 8.3 8. 6 8.9 8.9 9.1 9. 7 9.5 9.11 8.6 8.8 8.9 Calcium 39.5 35. 2 35.2 36.7 37.9 37.9 38.7 111.1 110.3 39-.9 36.3 37.5 38.0 Iron o 011.011.011.011.011.011.011.011.011.011.011.011.011 Silica 2.1 1.9 1.9 2.0 2.0 2.0 2.1 2.2 2.1 2.1 1.9 2.0 2.0 Alkalinity 100 89 89 93 96 96 98 1011 102 101 92 95 96.3

Year b922 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.!Avon) Temp. Lorain) 1 3 7 12 19 24 23 21 15 10 4 12.6 Total solids 176 170 167 157 170 176 174 176 179 177 179 179 173 Nitrat,e 1.28 1.24 1.21 1.15 1.24 1.28 1.27 1.28 1.31 1.29 1.31 1.31 1o26 Fluorlie.11.10.10.10 10 ll.1 1.11.11 11.ll.11.11 11 Chlortde 19.2 18.6 18.2 17.2 18.6 19.2 19.0 19.2 19.6 19.4 19.6 19.6 19.0 Sulphate 26.7 25.9 25.3 23.9 25.9 26.7 26.4 26.7 27,2 26.9 27.2 27.2 26.3 Bicarbonate 120 117 114 108 117 120 119 120 123 122 123 123 119 Sodium plus 101ol 9.8 9.6 9.0 98 9o.0 10,0 101 10.3 10.2 103 10. 9.9 potass ium. Magnesium 9.0 8.7 8.6 8.1 8.7 9.0 8.9 9.0 9.2 9.1 9.2 9.2 89 Calciuma 38.3 37.1 36~3 34.4 37.1 38.3 37.9 38.3 39.1 38.7 39.1 39.1 37.8 Iron.04.04.04.03.04.04.04 o.04.04.04 04 o04 04 Silica 2.0 2.0 1.9 1.8 2.0 2.0 2.0 2.0 2.1 2.1 2.1 2.1 2.0 Alkalii4ty 97 94 92 87 94 97 96 97 99 98 99 99 95.8

Year 1923 Ye arl y Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Tenp.(Lorain) 4 2 2 7 10 17 24 22 20 15 9 5 11.4 Total solids 168 176 170 176 172 179 183 188 190 188 183 170 179 Nitrate 1.23 1.28 1.24 1.28 1.25 1.31 1.33 1.37 1.39 1.37 1.33 1.24 1.30 Fluoride.10.11.10.11.10.11.11.11.12.11.11.10.11 Chloride 18.4 19.2 18.6 19.2 18.8 19.6 20.0 20.6 20.8 20.6 20.0 18.6 19.5 Sulphate 25.6 26.7 25.9 26.7 26.1 27.2 27.8 28.6 28.9 28.6 27.8 25.9 27.2 Bicarbonate 115 120 117 120 118 123 125 129 130 129 125 117 122 Sodium plus 9.7 10.1 9.8 10.1 9.9 10.3 10.5 0o.8 10.9 10.8 10.5 9.8 10.3 potassium Magnesium 8.6 9.0 8.7 9.0 8.8 9.2 9.4 9.7 9.8 9.7 9.4 8.7 9.2 Calcium 36.7 38.3 37.1 38.3 37.5 39.1 39.9 41.1 41.5 41.1 39.9 37.1 39.0 Iron.4.04 04 04.4.4.4.4.4 4.04.04.04 Silica 2.0 2.0 2.0 2.0 2.0 2.1 2.1 2.2 2.2 2.2 2.1 2.0 2.1 Alkalinity 93 97 94 97 95 99 101 104 105 104 101 94 98.7

Year 1924 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp.(Lorain) 2 2 6 12 17 22 22 19 15 9 3 11.7 Total solids 176 177 177 172 172 177 176 183 188 186 185 183 179 Nitrate 1.28 1.29 1.29 1.25 1.25 1.29 1.28 1.33 1.37 1.36 1.35 1.33 1.31 Fluoride.11.11.11.10.10.11.11.11.11.11.11.11.11 Chloride 19.2 19.4 19.4 18.8 18.8 19.4 19.2 20.0 20.6 20.4 20.2 20.0 19.6 Sulphate 26.7 26.9 26.9 26.1 26.1 26.9 26.7 27.8 28.6 28.3 28.0 27.8 27.2 Bicarbonate 120 122 122 118 118 122 120 125 129 128 126 125 123 Sodium plus 10.1 10.2 10.2 9.9 9.9 10.2 10.1 10.5 10.9 10.7 10.6 10.5 10.3 potassium PMagnesium 9.0 9.1 9.1 8.8 8.8 9.1 9.0 9.4 9.7 9.6 9.5 9.4 9.2 Calcium 38.3 38.7 38.7 37.5 37.5 38.7 38.3 39.9 41.1 40.7 40.3 39.9 39.1 Iron.04.04.04.04.04.04.04.04.04.04.04.04.04 Silica 2.0 2.1 2.1 2.0 2.0 2.1 2.0 2.1 2.2 2.2 2.1 2.1 2.1 Alkalinity 97 98 98 95 95 98 97 101 104 103 102 101 99.1

Year 1925 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp.(Lorain) 1 1 4 9 13 19 23 24 22 8 3 11.5 Total solids 192 181 179 181 183 188 188 185 185 183 179 185 184 Nitrate 1.40 1.32 1.31 1.32 1.33 1.37 1.37 1.35 1.35 1.33 1.31 1.35 1.34 Fluoride.12.11.11.11.11.11.11.11.11.11.11.11.11 Chloride 21.0 19.8 19.6 19.8 20.0 20.6 20.6 20.2 20.2 20.0 19.6 20.2 20.1 Sulphate 29.2 27.5 27.2 27.5 27.8 28.6 28.6 28.0 28.0 27.8 27.2 28.0 28.0 Bicarbonate 131 124 123 124 125 129 129 126 126 125 123 126 126 Sodium plus 11.0 10.4 10.3 10.4 10.5 10.8 10.8 10.6 10.6 10.5 10.3 10.6 10.6 potassium Magnesium 9.9 9.3 9.2 9.3 9.4 9.7 9.7 9.5 9.5 9.4 9.2 9.5 9.5 Calcium 41.9 39.5 39.1 39.5 39.9 41.1 41.1 40.3 40.3 39.9 39.1 40.3 40.2 Iron.04.04.04.04.04.04.04.04.04.04.04.04.04 Silica 2.2 2.1 2.1 2.1 2.1 2.2 2.2 2.1 2.1 2.1 2.1 2.1 Alkalinity 106 100 99 100 101 104 104 102 102 101 99 102 101.7

Year 1926 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) Temp.(Lorain) 1 1 3 6 13 20 25 25 22 15 9 2 11.8 Total solids 190 190 186 179 186 185 185 188 181 174 177 181 184 Nitrate 1.39 1.39 1.36 1.31 1.36 1.35 1.35 1.37 1.32 1.27 1.29 1.32 1.34 Fluoride.12.12.11.11.11.11.11.11.11.11.11.11.11 Chloride 20.8 20.8 20.4 19.6 20.4 20.2 20.2 20.6 19o8 19.0 19.4 19.8 20.1 Sulphate 28.9 28.9 28.3 27. 2 28.9 28.0 28.0 28.6 27.5 26.4 26.9 27.5 27.9 cs Bicarbonate 130 130 128 123 128 126 126 129 124 119 122 124 126 Sodiumn plus 10.9 10.9 10.7 10.3 10.7 10.6 10.6 10.8 10.4 10.0 10.2 10.4 10.5 potassium Magnesium 9.8 9.8 9.6 9.2 9.6 9.5 9.5 9.7 9.3 8.9 9.1 9.3 9.4 Calcium 41.5 41.5 40.7 39.1 40.7 40.3 40.3 41.1 39.5 37.9 38.7 39.5 40.1 Iron o.04.04.04.04.04.04.04.04.04.04 04 04.04 Silica 2.2 2.2 2.2 2.1 2.2 2.1 2.1 2.2 2.1 2.0 2.1 2.1 2.1 Alkalinity 105 105 103 99 103 102 102 104 100 96 98 100 101.4

Year 1927 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.1 1.4 3.3 8.6 13.5 17.5 22.6 21.9 20.3 15.3 8.8 2.5 11.4 Temp.(Lorain) 1 2 4 9 12 19 23 22 20 15 10 3 11.7 Total solids 167 170 172 179 179 183 181 177 179 179 168 176 Nitrate 1.21 1.24 1.25 1.31 1.31 1.33 1.32 1.32 1.29 1.31 1.31 1.23 1.29 Fluoride.10.10.10.11.11.11.11.11.11.11.11.10.11 Chloride 18.2 18.6 18.8 19.6 19.6 20.0 19.8 19.8 19.4 19.6 19.6 18.4 19.3 Sulphate 25.3 25.9 26.1 27.2 27.2 27.8 27.5 27.5 26.9 27.2 27.2 25.6 26.8 Bicarbonate 114 117 118 123 123 125 124 124 122 123 123 115 121 Sodium plus 9.6 9.8 9-9 10.3 10.3 10.5 10.4 10.4 10.2 10.3 10.3 9.7 10.1 potassium Magnesium 8.6 8.7 8.8 9.2 9.2 9.4 9.3 9.3 9.1 9.2 9.2 8.6 9.1 Calcium 36.3 37.1 37.5 39.1 39.1 39.9 39.5 39.5 38.7 39.1 39.1 36.7 38.5 Iron.04.04.04.04.04.04.04.04.04.04.04.04.0 Silica 1.9 2.0 2.0 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.0 2.1 Alkalinity 92 94 95 99 99 101 100 100 98 99 99 93 97.4

Year 1928 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.4 1.0 1.9 6.7 12.7 17.3 23.6 24.3 18.6 14.6 7.8 2.8 111 Temp.(Lorain) 1 3 5 9 16 23 24 22 14 9 3 117 Total solids 177 176 179 172 177 179 181 179 181 185 183 177 179 Nitrate 1.29 1.28 1.31 1.25 1.29 1.31 1.32 1. 31 1.32 1.35 1.33 1.29 1.30 Fluoride.11.11.11.10.11.11.11.11.11.11.11.11.11 Chloride 19.4 19.2 19.6 18.8 19.4 19.6 19.8 19.6 19.8 20.2 20.0 19.4 19.6 Sulphate 26.9 26.7 27.2 26.1 26.9 27.2 27.5 27.2 27.5 28.0 27.8 26.9 272 CD 03 Bicarbonate 122 120 123 118 122 123 124 123 124 126 125 122 123 Sodium plus 10.2 10.1 10.3 9.9 10.2 10.3 10.4 10.3 10.4 10.6 10.5 10.2 10.3 potassium Magnesium 9.1 9.0 9.2 8.8 9.1 9.2 9.3 9.2 9.3 9.5 94 9.1 92 Calcium 38.7 38.3 39.1 37.5 38.7 39.1 39.5 39.1 39.5 40.3 39.9 38.7 390 Iron.04.04 o.04.04.04.04.04.04.04.04.04.04.04 Silica 2.1 2.0 2.1 2.0 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 Alkalinity 98 97 99 95 98 99 100 99 100 102 101 98 98.8

Year 1929 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.1 1.1 4.5 9.3 12.7 19.6 22.9 22.3 19.8 13.3 7.4 1.6 11.3 Temp.(Lorain) 1 1 4 9 11 19 23 21 15 8 1 9.4 Total solids 165 167 161 157 170 174 181 185 186 181 174 172 173 Nitrate 1.20 1.21 1.17 1.15 1.24 1.27 1.32 1.35 1.36 1.32 1.27 1.25 1.26 Fluoride.10.10.10.10.10.11.11.11.11.11.11.10.10 Chloride 18.0 18.2 17.6 17.2 18.6 19.0 19.8 20.2 20.4 19.8 19.0 18.8 18.9 Sulphate 25.0 25.3 24.5 23.9 25.9 26.4 27.5 28.0 28.3 27.5 26.4 26.1 26.2 co Bicarbonate 113 114 110 108 117 119 124 126 128 124 119 118 118 Sodium plus 9.5 9.6 9.3 9.0 9.8 10.0 10.4 10.6 10.7 10.4 10.0 9.9 9.9 potassium Magnesium 8.5 8.6 8.3 8.1 8.7 8.9 9.3 9.5 9.6 9.3 8.9 8.8 8.9 Calcium 35.9 36.3 35.2 34.4 37.1 37.9 39.5 40.3 40.7 39.5 37.9 37.5 37.7 Iron.04.04.04.03.04.04.04.04.o4.04.04.04.04 Silica 1.9 1.9 1.9 1.8 2.0 2.0 2.1 2.1 2.2 2.1 2.0 2.0 2.0 Alkalinity 91 92 89 87 94 96 100 102 103 100 96 95 95.4

Year 1930 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.8 2.6 2.9 7.3 13.8 19.5 23.2 23.6 20.9 13.8 7.2 2.2 11.6 Temp.(Lorain) Total solids 159 174 163 168 177 182 181 181 181 183 177 176 175 Nitrate 1.16 1.27 1.19 1.23 1.29 1.33 1.32 1.32 1.32 1.33 1.29 1.28 1.28 Fluoride.10.11.10.10.11.11.11.11.11..11.11.11 Chloride 17.4 19.0 17.8 18.4 19.4 20.0 19.8 19.8 19.8 20.0 19.4 19.2 19.2 Sulphate 24.2 26.4 24.7 25.6 26.9 27.8 27.5 27.5 27.5 27.8 26.9 26.7 26.6 co Bicarbonate 109 119 112 115 122 125 124 124 124 125 122 120 120 Sodium plus 9.2 10.0 9.4 9.7 10.2 10.5 10.4 10.4 10.4 10.5 10.2 10.1 10.1 potassium Magnesium 8.2 8.9 8.4 8.6 9.1 9.4 9.3 9.3 93 9.4 9.1 9.0 9.0 Calcium -V34. 4 37.9 35.5 36.7 38.7 39.9 39.5 39.5 39.5 39.9 38.7 38.3 38.2 Iron.04.04.04.04.04.04.04.04.04.04.04.04.04 Silica 1.8 2.0 1.9 2.0 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.0 2.0 Alkalinity 88 96 90 93 98 101 100 100 100 101 98 97 96.8

Year 1932 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon).9 1.6 2.4 8.1 12.7 19.2 25.8 23.6 22.3 16.1 10.5 5.6 12.4 Temp. (Lorain) Total solids 172 165 163 163 170 172 172 174 172 176 174 174 170.6 Nitrate 1.25 1.20 1.19 1.19 1.24 1.25 1.25 1.27 1.25 1.28 1.27 1.27 1.24 Fluoride.10.10.10.10.10.10.10.11.10.11.11.11.10 Chloride 18.8 18.0 17.8 17.8 18.6 18.8 18.8 19.0 18.8 19.2 19.0 19.0 18.6 Sulphate 26.1 25.0 24.7 24.7 25.9 26.1 26.1 26.4 26.1 26.7 26.4 26.4 25.9 Bicarbonate 118 113 112 112 117 118 118 119 118 120 119 119 117 Sodium plus 9.9 9.5 9.4 9.4 9.8 9.9 9.9 10.0 9.9 10.1 10.0 10.0 9.8 potassium Magnesium 8.8 8.5 8.4 8.4 8.7 8.8 8.8 8.9 8.8 9.0 8.9 8.9 8.7 Calcium 37.5 35.9 35-5 35.5 37.1 37.5 37.5 37.9 37.5 38.3 37.9 37.9 37.2 Iron.04.04.04.04.04.04.04.04.04.04.04.04.04 Silica 2.0 1.9 1.9 1.9 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Alkalinity 95 91 90 90 94 95 95 96 95 97 96 96 94.2

Year 1932 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) 5.0 2~8 2.1 71.9 20 - Tep.(Avon) 5.0 28 2.1 7.1 13.9 20.0 23.7 23.6 21.0 13.8 7.2 2.5 11.9 Temp. (Lorain) Total solids 163 167 170 170 172 176 174 172 176 179 172 168 171.6 Nitrate 1.19 1.21 1.24 1.24 1.25 1.28 1.27 1.25 1.28 1.31 1.25 1.23 1.25 Fluoride o10.10.10.10.10.11.11.10.11.11.10.10.10 Chloride 17.8 18.2 18.6 18.6 18.8 19.2 19.0 18.8 19.2 19.6 18.8 18.4 18.8 Sulphate 24.7 25.3 25.9 25.9 26.1 26.7 26.4 26.1 26.7 27.2 26.1 25.6 26.1 Od Bicarbonate 112 114 117 117 118 120 119 118 120 123 118 115 118 Sodium plus 9.4 9.6 9.8 9.8 9.9 10.1 10.0 9.9 10.1 10.3 9.9 9.7 99 potassium Magnesium 8.4 8.6 8.7 8.7 8.8 9.0 8.9 8.8 9.0 9.2 8.8 8.6 8.8 Calcium 35.5 36.3 37.1 37.1 37.5 38.3 37.9 37. 5 38.3 39.1 37.5 36.7 37.3 Iron.04.04.014.01.0.0.01.0 04.0o4 o4 o04.0 Silica 1.9 1.9 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.1 2.0 2.0 2.0 Alkalinity 90 92 94 94 95 97 96 95 97 99 95 93 94.8

Year 1933 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) 2.9 1.8 2.6 8.1 13.8 21.8 22.9 24.1 21.5 14.3 5.6 3.3 11.9 Temp. (Lorain) Total solids 163 172 168 165 167 181 177 177 179 176 176 161 172 Nitrate 1.19 1.25 1.23 1.20 1.21 1.32 1.29 1.29 1.31 1.28 1.28 1.17 1.25 Fluoride.10.10.10.10.10.11.11.11.11.11.11.10.10 Chloride 17.8 18.8 18.4 18.0 18.2 19.8 19.4 19.4 19.6 19.2 19.2 17.6 18.8 Sulphate 24.7 26.1 25.6 25.0 25.3 27.5 26.9 26.9 27.2 26.7 26.7 24.5 26.1 Os Bicarbonate 112 118 115 113 114 124 122 122 123 120 120 110 118 Sodium plus 9.4 9.9 9.7 9.5 9.6 10.4 10.2 10.2 10.3 10.1 10.1 9.3 9.9 potassium Magnesium 8.4 8.8 8.6 8.5 8.6 9.3 9.1 9.1 9.2 9.0 9.0 8.3 8.8 Calcium 35.5 37-5 36.7 35.9 36.3 39.5 38.7 38.7 39.1 38.7 38.7 35.2 37.5 Iron.04.04.o04.04.04.04.04.04.04.04.04.04.o4 Silica 1.9 2.0 2.0 1.9 1.9 2.1 2.1 2.1 2.1 2.0 2.0 1.9 2.0 Alkalinity 90 95 93 91 92 100 98 98 99 97 97 89 94.9

Ic~~~~~~~~~~~~~~~~~~~~~~~Yarly93 Jan. Feb..Mar. Apr. May June Jul y Aug. Sept. Oct. Nov. Dec. v Temp. (Avon) 1.8 1o6 1.9 6~4 14,2 21.1 24~9 24o1 20.8 14,8 1 27 Temp.- (Lorain) Total solids 152 156 148 141 154 152 157 167 172 170 170 165 Nitrate 1 ~11 1.14 1 ~08 1 ~03 1.12 1 oll 1.15 1.21 1.25 1 ~24 1.24 1.20.1 Fluoride.09.09 ~09 ~09.09.09.10 ol0 ol0.10.10.10o0 Chloride 16.6 17o0 16.2 15o4 16.8 16o6 17o2 18o2 18o8 18.6 18.6 18,0 7o Sulphate 23ol 23~7 22,5 21o4 23~4 23ol 23~9 25,3 26,1 251.9 25,9 25,0 4o co o~1 ]Bicarbonate!04 107 102 97 105 104 108 114 118 117 117 11310 Sodium plus 8,7 8,9 8~5 8,1 8,8 8.-7 9~0 9~6 9. 98 98 potassium Magnesium 7.8 8.0 7.6 7-3 7.9 7.8 8.1 8.6 8.8 87 87 5 Calcium 33,2 34,o 0 32, 30,8 33~6 33,2 34,4 36~3i 37,5 37.1 37ol 35,9 3, Iron.03,03,03.03,03 ~03 ~03,04.04,04 o04 ~04,0 Silica y,8 1o8 1.7 1o6 1.8 1.8 1.8 1.9 2.0 2.0 2.0 1.9 20 Alkalinity A4 86 82 78 85 84 87 92 95 94 94 91 8,

Year 1935 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Avo Temp. (Avon) 1.9 1.6 4.9 8.2 13.0 18.8 24.8 25.2 20.4 13.7 9.3 2.6 Temp. (Lorain) Total solids 167 165 156 159 159 163 170 170 170 172 174 172 Nitrate 1.21 1.20 1.14 1o16 1.16 1.19 1.24 1.24 1.24 1.25 1.27 1.25 IL 2_ Fluoride.10.10 O.09.O.10.10.10.10.10.0.0 11.10 Chloride 18.2 18.0 17.0 17.4 17.4 17.8 18.6 18.6 18.6 18.8 19o0 18.8 18.2 Sulphate 25.3 25.0 23.7 24,2 24.2 24.7 25.9 25.9 25.9 26.1 26.4 26.1 co -x Bicarbonate 114 113 107 109 109 112 117 117 117 118 119 118 ll4 Sodium plus 9.6 9.5 8.9 9.2 9.2 9.4 9.8 9.8 9.8 9.9 10.0 9.9 potassium Magnesium 8.6 8.5 8.0 8.2 8.2 8.4 8.7 8.7 8.7 8.8 8.9 8.8 Calcium 36.3 35.9 34.0 34.8 34.8 35.5 37.1 37.1 37-1 37.5 37.9 37.5 Iron.04.04.03 o04.04.04.04.04.04.04.04.04.04 Silica 1.9 1.9 1.8 1.8 1.8 1.9 2.0 2.0 2.0 2.0 2.0 2.0 1.9 Alkalinity 92 91 86 88 88 90 94 94 94 95 96 95

Year 1936 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) 1.7 1.3 3~3 6.4 14.8 20.1 239 4. 219 1.9 66.6 18 Temp. (Lorain) 176 177 172 161 168 17 10 12 12 10 16 10 10 Nitrate 1.28 1.29 1.25 1.17 1.23 1.24 1o 24 1o.25 1.25 1. 24 1.23 1,24 12 Fluoride.11.11.10.10.10.10.10.10.10.10.10.10.10 Chloride 19.2 19.4 18.8 17.6 18.4 18.6 18.6 18.8 18.8 18.6 18o4 18.6 10 Sulphate26.7 269 26.1 2.5 25.6 25.9 25.9 26.1 26.1 25.9 25.6 25.9 25.9 Bicarbonate 120 122 118 110 115 117 117 118 118 17 15 17 17 Oo Sodiu plu 10.110.2 9.9 9.3 9.7 9.8 9.8 9.9 9.9 9~8 9.7 9.8 9.18 potassium Magnesium 9.0 9.1 8.8 8.3 8.6 8. 87 88 88 87 6 87 87 Calcium 38.3 38.7 37.5 35.2 36.7 37.1 37-1 75 35 3.1 6- 37 72 Iron.0o4.0 o 0. o4 0 4.0o4.0o4.04.04.0 04 oh 04.04 0 Silica 2.0 2.1 2.0 1-9 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Alkainit 97 98 9 89 93 94 94 95 95 94 93 94 94. 3

Year 1937 Yearl y Jan. Feb. Mar. Apr. May June July Aug, Sept. Oct. Nov. Dec. Av. Temp. (Avon) 2.9 1.8 1.7 7.2 13.6 20.2 238 23.9 20.3 12.9 6.2 1.8 11.4 Temp.(Lorain) Total solids 150 150 156 157 163 170 167 170 172 174 172 168 164 Nitrate 1.10 1.10 1.14 1.15 1.19 1.24 1.21 1.24 1.25 1.27 1.25 1.23 1.20 Fluoride.09.09.09..10 l.10.10.10.10.11.10.10.10 Chloride 16.4 16.4 17.0 17.2 17.8 18.6 18.2 18.6 18.8 19.0 18.8 18.4 179 Sulphate 22.8 22.8 23.7 23.9 24.7 25.9 25.3 25.9 26.1 26.4 26.1 25.6 24.9 CO \1 Bicarbonate 103 103 107 108 112 117 114 117 118 119 118 115 113 Sodium plus 8.6 8.6 8.9 9.0 9.4 9.8 9.6 9.8 9.9 10.0 9.9 9.7 94 potassium Magnesium 7.7 7.7 8.0 8.1 8.4 8.7 8.6 8.7 8.8 8.9 8.8 8.6 8.4 Calcium 32.8 32.8 34.0 34.4 35.5 37.1 36.3 37. 175 3.7 358 35.5 37.1 36.33 7.15., 37.9 37.5 36.7 3. Iron.03 ~.03.03 ~.03.04.04.04.04.04.04.04.04.04 Silica 1.7 1.7 1.8 1.8 1.9 2.0 1.9 2.0 2.0 2.0 2.0 2.0 1.9 Alkalinity 83 83 86 87 90 94 92 94 95 96 95 93 97

Ye1ar 1938 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) 1.3 3.3 4.4 9.1 14.2 19.9 23.9 24.9 20.5 15.6 9.0 3.7 Temp. (Lorain) Total solids 174 163 159 161 168 170 167 165 167 168 167 167 166 Nitrate 1.27 1.19 1.16 1.17 1.23 1.24 1.21 1.20 1.21 1.23 1.21 1.21 1.21 Fluoride.11.10.10.10.10.10.10.10.10.10.lO.10.10 Chloride 19.0 17.8 17.4 17.6 18.4 18.6 18.2 18.0 18.2 18.4 18.2 18.2 18.2 Sulphate 26.4 24.7 24.2 24.5 25.6 25.9 25~ 3 25.0 25.3 25.6 25.3 25.3 25.3 ED Bicarbonate 119 112 109 110 115 117 114 113 114 115 114 114 114 Sodium plus 10.0 9.4 9-2 9.3 9~7 9.8 9~6 9.5 9.6 9-7 9. 6 9. 6 potassium Magnesium 8.9 8.4 8.2 8.3 8.6 8.7 8.6 8.5 8.6 8.6 8.6 8.6 8.6 Cale'um 37.9 35.5 34.8 35.2 36.7 37.1 36.3 35.9 36.3 36.7 36-3 36. 3 lum~~~~~~~~~~~~3. 35. 36. 3 6 7 6. 3.363 Iron.04.o4 o04.o4.o4 o04 o4 o4 o4 o4 o4.04 4 Silica 2.0 1.9 1.8 1.9 2.0 2.0 1.9 1.9 1o9 2.0 1.9 1.9 1.9 Alkalinity 96 90 88 89 93 94 92 91 92 93 92 92 91.8

Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Avo Temp. (Avon) 2.2 1.7 3.1 6.9 14.2 20.9 24 0 24.7 2!.9 15~5 7.4 4.0 12.2 Temp. (Loratn) Total solids 167 159 154 156 159 159 161 165 165 165 163 159 161 Nitrate 1.21 1.16 1.12 1.14 1.16 1.16 1.17 1.20 1.20 1.20 1.19 1.16 1.17 Fluoride.lO.lO.09.09.lO.lO.lO.lO.lO.lO.lO.lO.10 Chloride 18.2 17.4 16.8 17.0 17.4 17.4 17.6 18.0 18.0 18.0 17o8 17.4 17o6 Sulphate 25.3 24.2 23.4 23.7 24.2 24.2 24.5 25.0 25,.0 25.0 24.7 24.2 24~ 5 kO Bicarbonate 114 109 105 107 109 109 110 113 ll 3 113 112 109 llO Sodium plus 9.6 9.2 8~8 8.9 9.2 9.2 9.3 9.5 9.5 9.5 9.4 9.2 9.3 potassium Magnesium 8.6 8~2 7-9 8.0 8.2 8.2 8.3 8.5 8.5 8.5 8.4 8.2 8.3 Calcium 36.3 34.8 33.6 34.0 34.8 34.8 35.2 35.9 35-9 35.9 35.5 34.8 35.1 Iron.04.04.OB.OB.04.04.04.04.04.04.04.04.04 Silica 1.9 1.8 1.8 1.8 1.8 1.8 1.9 1.9 1.9 1.9 1.9 1.8 1.85 Alkalinity 92 88 85 86 88 88 89 91 91 91 90 88 88.9

Year 1940 Yearly Jan.o Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Avo Tempo (Avon) 1.8 1.5 1.6 4.4 12.2 19.8 22.8 23.1 20.4 15.4 7-9 3.6 Temp. (Lorain) Total solids 167 167 157 136 150 154 156 159 157 156 157 156 156 Nitrate 1o21 1.21 1o15.99 1.10 1.12 1.14 1.16 1.15 1.14 1.15 1.14 1.1 4 Fluoride.10.10.10.08.09.09.09.10.10.09 o10.09.09 Chloride 18.2 18.2 17.2 14o8 16.4 16.8 17o0 17.4 17o2 17,0 17o2 17.0 17.0 Sulphate 25.3 25.3 23.9 20.6 22,8 23 4 23.7 24.2 23 9 23.7 23 9 23.7 Bicarbonate 114 114 108 93 103 105 107 109 108 107 108 107 107 Sodium plus 9.6 9~6 9~0 7~8 8.6 8.8 8 9 9.2 9.0 8.9 9.0 8 9 potassium Magnesium 8.6 8. 6 8.1 7.0 7-7 7 9 8.0 8.2 8.1 8.0 8o1 8.0 8~0 Calcium 36.3 36~3 34~4 29.6 32.8 33~6 34~0 34~8 34~4 34.0 34.4 340o Iron 04 o04. 03.03,03.03 ~03 o4.03 ~03 O03 03 ~3 Silica 1.9 1.9 1.8 1o6 1.7 1.8 1.8 1.8 1.8 1o8 1.8 1.8 1o 8 Alkalinity 92 92 87 75 83 85 86 88 87 86 87 86 86c2

Year 1941 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) 1.7 1o8 2.1 7.7 16.2 20.4 24.5 24~5 21.6 16.1 8.0 4.8 Temp. (Lorain) Total solids 152 161 165 161 165 163 161 161 167 170 170 167 164 Nitrate 1.11 117 1.20 1.17 1.20 1.19 1.17 1.17 1.21 1.24 1.24 1.21 1o19 Fluoride, 09.10 lO.10 l10.10.1O.O0.10.10 olO.10 Chloride 16o6 17.6 18.0 17.6 18.0 17.8 17.6 17.6 18o2 18o6 18.6 18.2 17o9 Sulphate 23.1 24.5 25.0 24.5 25.0 24.7 24.5 24.5 25.3 25.9 25.9 25.3 Bicarbonate 104 110 113 110 113 112 110 110 114 117 117 l14 112 Sodium plus 8.7 9.3 9~5 9.3 9.5 9.4 9.3 9.3 9.6 9.8 9.8 9.6 potassium Magnesium 7.8 8.3 8.5 8.3 8.5 8.4 8.3 8.3 8.6 8.7 8.7 8.6 8.4 Calcium 33.2 35.2 35.9 35.2 35.9 35.5 35.2 35-2 36-3 37o1 37.1 36.3 35.7 Iron ~ 03 o04 o04 o04.04 o04 04.o4 04.o4.04 o04 Silica 1.7 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 2.0 2.0 1.9 1.9 Alkalinity 84 89 91 89 91 90 89 89 92 94 94 92 90.3

Year 1942 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) 2.2 1.7 3.9 9.2 14.1 19.7 23.8 24.1 20.8 8 1.8 11 Temp. (Lorain) Total solids 168 154 150 147 157 161 163 163 168 174 170 167 162 Nitrate 1.23 1,12 1.10 1.07 1.15 1.17 1.19 1.19 1.23 1.27 1.24 1.21 1.18 Fluoride.10.09.09 09.10.10.10.10.10.11.10.10.10 Chloride 18.4 16.8 16.4 16.0 17.2 17.6 17.8 17.8 18.4 19.0 18o6 18.2 17.7 Sulphate 25 6 23.4 22.8 22,3 23.9 24.5 24.7 24.7 25.6 26.4 25.9 25.3 24.6 Bicarbonate 115 105 103 100 108 110 112 112 115 119 117 114 111 Sodium plus 9.7 8.8 8.6 8.4 9.0 9.3 9.4 9.4 9.7 10.0 9,8 9.6 9,3 potassium Magnesium 9.6 7.9 7.7 7.5 8,1 8.3 8.4 8.4 8.6 8.9 8.7 8.6 8.4 Calcium 36.7 33.6 32.8 32.0 34.4 35.2 35.5 35~5 36.7 37.9 37.1 36.3 35.3 Iron.04.03.03.03.03.04.04.04.04.04.04.04.04 Silica 2.0 1.8 1.7 1.7 1.8 1.9 1.9 1.9 2.0 2.0 2.0 1.9 1.9 Alkalinity 93 85 83 81 87 89 90 90 93 96 94 92 89,4

Year 1943 Yearly Jan. Feb. Mar. Apro May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 2.0 1.6 3.4 7.2 12.6 20.8 24.5 24.6 19.7 141 68 2.6 117 Temp. (Lorain) Total solids 161 172 168 165 165 165 168 170 170 167 170 167 Nitrate 1.17 1.25 1.23 1.20 1.20 1.20 1.23 1.24 1.24 1.21 1.24 1 22 Fluoride.10.10 o 10.10. 10.10.10. 10.1 0. 10.10 10 Chloride 17.6 18.8 18.4 18.0 18.0 18,0 18.4 18.6 18.6 18.2 18.6 18.3 Sulphate 24.5 26.1 25.6 25.0 25.0 25.0 25.6 25.9 25.9 25.3 25.9 25.5 Bicarbonate 1i0 118 115 113 113 113 115 117 117 114 117 115 Sodiumn plus 9.3 9.9 9.7 9.5 9.5 9.5 9.7 9.8 9.8 9.6 9.8 9.6 potassium Magnesium 8.3 8.8 8.6 8.5 8.5 8,5 8.6 8.7 8.7 8.6 8.7 806 Calcium 35.2 37.5 36.7 35.9 35.9 35.9 36.7 37.1 37.1 36.3 37.1 36.5 Iron.04.04.04.04.004 4.04.4.04.04.04.04 Silica 1.9 2.0 2.0 1.9 1.9 1.9 2.0 2.0 2.0 1.9 2.0 1.9 Alkalinity 89 95 93 91 91 91 93 94 94 92 94 92.5

Year 1944 Yearl y Jan. Feb,, Mar~ Apr. May June July Augo Sept. Oct. Nov~ Dec~ Av~ Temp. (Avon) 19 204 2o6 6o4 14.1 21.3 23-9 23.6 20c2 15.3 8.8 2.1 Temp. (Lorain) Total solids 170 165 154 157 161 165 167 170 172 168 163 165 Nitrate 1.24 1o20 1o12 1.15 1017 1~20 1o21 1~24 1o25 1.23 1.19 1.20 1.20 Fluoride o10 o10 o09 o10 o10 o!0 o10.10.10.10.10 o10 Chloride 18o6 1800 16o8 17o2 17o6 18o0 18o2 18.6 18o8 18o4 17.8 18o0 18.0 Sulphate 25.9 25o0O 23~ 4 23. 9 24~ 5 25o0 2$ -3 25~ 9 26.1 25~ 6 24 e7 25.0 25~ 0 \0 Bicarbonate 117 113 105 108 110 113 114 117 118 115 112 113 113 Sodium plus 9.8 9~5 8~8 9o0 9-3 9.5 9.6 9.8 9.9 9o7 9.4 9.5 potassium Magnesium 8.7 8~5 7~9 8o1 8~3 8~5 8~6 8.7 8~8 8~6 804 8.5 Calcium 37o1 3509 33~4 34.4 35~2 35.9 36.3 37o1 37~5 36~7 35~5 359 35~ 9 Iron o 04 o 04 ~ 03.04 o 04.04 o 04 o04 o04 o04 o 04 o 04 e 04 Silica 2~0 1.9 1o8 1.8 1.9 1 9 1o9 2~0 2.0 2~0 1o9 179 lo9 Alkalinity 94 91 85 87 89 91 92 94 95 93 90 91 91

Year 1945 Yeal Jano Feb. Maro Apr. May June July Aug~ Sept. Oct. Nov. Dec~ Avo Temp.(Avon) 1,7 lol 6~0 10o3 12o6 18.3 23o1 24.2 20,8 13.7 9~2 2.3 1lo9 Tempo (Lorain) Total solids 168 167 152 152 157 167 165 165 168 165 163 163 163 Nitrate 1,23 1o21 1 o11 l oll 1.15 1 o21 1 ~20 1o20 1 o23 1 ~20 1 o19 1.19 l e19 Fluoride.10 o10 ~09 0o09.10 o10.10.10 ot0 1 10 o10 o10 o10 Chloride 18o4 18e2 16o6 16o6 17.2 18.2 18.0 18,0 18o4 18.0 17.8 17o8 17.8 Sulphate 25~6 25~3 23.1 23.1 2309 25 3 25o0 25o0 25~6 25.0 24~7 24 7 24 7 Bicarbonate 115 114 104 104 108 114 113 113 115 113 112 112 Lll Sodium plus 9-7 9~6 8~7 8-7 9,0 9e6 9~5 905 9~7 9~5 9,4 9~4 904 potassium Magnesium 8.6 8o6 7.8 7o8 8o1 8e6 8o5 8.5 8.6 8.5 8.4 8.4 8. 4 Calcium 36~7 36,3 33.2 33~2 24,4 26.3 35.9 35.9 36 7 35~9 35~5 35.5 35.5 Iron o~4 o~4 03.03 ~03 o04 o04 04 o04 o04 o04 o04.04 Silica 2,0 1o9 1o8 1o8!c8 1 o9 1o9 1.9 2.0 1.9 1lo9 1 9 9 Alkalinity 93 92 84 84 87 92 91 91 93 91 90 90 89o 8

Year 1946 Yearly Jan. Feb. Mar Apr. May June July Aug. Sept. Oct. Nov. Dee Temp. gAvona) 1.8 1 O3 5 39 9.7 13o7 19.4 22.9 22~9 20~5 16.2 l1o4 3,7 12.4 Temp (lorain) Total solids 152 159 165 165 168 157 161 163 167 165 163 161 Nitrate 111 1o16 1.20 1.20 1.23 1Lo5 1.17 1.19 1o2 1.20 1519 lar Fluoride.09 o10 o10 o10 "10 o10 o! 0 olO o19 1 10 Chloride 16o6 17o4 18-0 18,0 18.4 17.2 17.6 17.8 18r2 18.0 17.8 176 1 Sulphate 23 -iL 24.2 25.0 2500 25~6 2309 24~5 24~7 25.3 25.0 24e7 24~5 2406',D co Bicarbonate 104 109 113 113 115 108 110 112 114 113 112 110 ll1 Sodium pluls 8.7 9o2 905 9o5 9.7 9o0 9.3 9o4 9o6 9o5 904 9~3 9. 3 potassium Magnesium 7.8 8~2 8~5 8.5 8~6 8.1 8.3 8.4 8.6 8.5 8c 8.3 Calcium 33~ 2 34.8 35o 9 35 09 3f6 7 34.4 32 35~ 35~ 5 36.3 35~ 9 35~ 5 35~ 5 Iron o 03 o04 o04 o04 o 04 o 03 o 04 o 044 o4 o4 o4 Silica 1o8 1o8 1o9 1o9 2.0 1.8 1.9 1.9 1o9 1 9 1.9 1o9 1o9 Alkalinity 84 88 91 91 93 87 89 90 92 91 90 89

Year 1947 Yearly Jan. Feb. Mar. Apr. May Junxe July Aug. Sept. Oct. Nov. Dec. Av. Temp. (Avon) lo9 1.4 1o6 7.3 11.7 17.5 22.6 25~2 22.6 17.3 9.0 2.7 11.7 Temp. (Lorain) Total solids 156 156 159 143 141 154 163 167 167 167 165 163 158 Nitrate 1.14 1.14 1.16 1.04 1.03 1.12 1o19 1.21 1.21 1.21 1.20 1o90 1.15 Fluoride.09.09.10.09.09.09.10.10 o10.10.10.10.10 Chloride 17.0 17.0 17.4 15.6 15.4 16.8 17.8 18.2 18.2 18.2 18.0 17.8 17.3 Sulphate 23.7 23.7 24. 2 21. 7 21.4 23.4 24.7 25.3 25.3 25.3 25. 0 24.7 24.0 k~O Bicarbonate 107 107 109 98 97 105 112 114 114 114 113 112 108 Sodium plus 8.9 8.9 9.2 8.2 8.1 8.8 9.4 9.6 9.6 9.6 9.5 9.4 9ol potassium Magnesium 8.0 8.0 8.2 7.3 7.3 7.9 8.4 8.6 8.6 8.6 8.5 8.4 8.1 Calcium 34.0 34.0 34.8 31.2 30.8 33.6 35.5 36.3 36.3 36.3 35.9 35.5 34.5 Iron.03.03.04.03.03.03.04.04.04.04.04.o4.03 Silica 1.8 1.8 1.8 1.7 1.6 1.8 1.9 1.9 1.9 1.9 1.9 1.9 1.8 Alkalinity 86 86 88 79 78 85 90 92 92 92 91 90 87.4

Year 1948 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.7 1.4 4.4 9.9 14.8 19.9 23.7 23.8 21.9 13.8 9.7 5.8 12.6 Temp. (Lorain) Total solids 163 161 157 154 156 163 163 161 159 159 165 161 160 Nitrate 1.19 1.17 1.15 1.12 1.14 1.19 1.19 1.17 1.16 1.16 1.20 1.17 1,17 Fluoride.10.10.10 0.09.09.10.10.10.10.10.10.10.10 Chloride 17.8 17.6 17.2 16.8 17.0 17.8 17.8 17.6 17.4 17.4 18.0 17.6 17.5 Sulphate 24.7 24.5 23.9 23.4 23.7 24 7 24.7 24.5 24.2 24.2 25.0 24.5 24 3 Bicarbonate 112 110 108 105 107 112 112 110 109 109 113 110 110 Sodium plus 9.4 9.3 9.0 8.8 8.9 9.4 9.4 9,3 9.2 9.2 9,5 9.3 9.2 potassium Magnesium 8.4 8.3 8.1 7.9 8.0 8.4 8.4 8.3 8.2 8.2 8.5 8.3 8.2 10* 6,4* 5.9* 5.5* 6.2* 6.6* 6.2* 6.7* 6.4* 6,4* 6.3* Calcium 35.5 35.2 34.4 33.6 34.0 35.5 35.5 35.2 34.8 34.8 35.9 35.2 35.0 Iron.04.04.03.03 03.04.04.04.04.04 04.04 Silica 1.9 1.9 1.8 1.8 1.8 1.9 1.9 1.9 1.8 1.8 1.9 1.9 1o9 Alkalinity 90 89 87 85 86 90 90 89 88 88 91 89 88.5 *-Observed magnesium

Year 1949 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 4,1 3.9 5.2 9.5 15.6 21.4 25.2 25.4 19.7 16.6 8.7 4.3 13.3 Temp. (Lorain) Total solids 159 159 159 154 156 156 159 163 161 163 165 157 159 Nitrate 1.16 1.16 1.16 1.12 1.14 1.14 1.16 1.19 1.17 1.19 1.20 1.15 1.16 Fluoride.10.10.10.09.09.09.10.10.10.10.10.10.10 Chloride 17.4 17.4 17.4 16.8 17.0 17.0 17.4 17.8 17.6 17.8 18.0 17. 2 17.4 Sulphate 24.2 24.2 24.2 23. 4 23.7 23.7 24.2 244.7 24.5 24.7 25.0 23.9 24.2 Bicarbonate 109 109 109 105 107 107 109 112 110 112 113 108 109 Sodium plus 9.2 9.2 9.2 8.8 8.9 8.9 9.2 9.4 9.3 9.4 9.5 9.0 9.2 potassium Magnesium 8.2 8.2 8.2 7.9 8.0 8.0 8.2 8.4 8.3 8.4 8.5 8.1 8.2 6.5* 6.4* 7-4* 6.7* 5.9* 5-7* 5.7* 5.5* 5.4* 5.5* 5,2* 5.1* Calcium 34.8 34.8 34.8 33.6 34.0 34.0 34.8 35.5 35.2 35.5 35.9 34.4 34.8 Iron.04.04.04.03.03.03.04.04.04.04.04.03.04 Silica 1.8 1. 8 1. 8 1. 8 1. 8 1.8 1.9 1.9 1.9 1.9 1.8 1.8 Alkalinity 88 88 88 85 86 86 88 90 89 90 91 87 88 *Observed magnesium

Year 1950 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 4.8 3.2 2.2 6.8 11.9 19.4 21.9 23.4 20.3 16.0 9.2 2.7 11.8 Temp. (Lorain) Total solids 145 147 148 154 154 163 165 165 167 165 163 154 157 Nitrate 1.06 1.07 1.08 1.12 1.12 1.19 1.20 1.20 1.21 1.20 1.19 1.12 1.15 Fluoride.09.09.09.09.09.10.10.10.10.10.10.09.10 Chloride 15.8 16.0 16.2 16.8 16.5 17.8 18.0 18.0 18,2 18.0 17.8 16.8 17.2 Sulphate 22.0 22.3 22.5 23.4 23.4 24.7 25 0 25.0 25.3 25.0 24.7 23-4 23c9 Bicarbonate 99 100 102 105 105 112 113 113 114 113 112 105 108 Sodium plus 8.3 8.4 8.5 8.8 8.8 9.4 9.5 9.5 9.6 9,5 9.4 8.8 9.0 potassium Magnesium 7.4 7.5 7.6 7.9 7.9 8.4 8.5 8.5 8.6 8.5 8.4 7.9 8.1 6.o 2* 5, 7* 6.3* 7o6* 8.3* 9.2* 9.1* 8.9* 8,5* 8.5* 8*5* 8.8* Calcium 31.6 32.0 32.4 33.6 33.6 35.5 35.9 35.9 36.3 35.9 35.5 33-6 34.3 Iron.03.03.03.03.03.04 04.0.04.04.04 03 03 Silica 1.7 1.7 1.7 1.8 1.8 1.9 1.9 1.9 1.9 1.9 1.9 1.8 1.8 Alkalinity 80 81 82 85 85 90 91 91 92 91 90 85 86.9 *Observed magnesium

Year 1951 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av Temp.(Avon) 2.2 2.0 5.4 8.0 13.8 20.5 23.3 23.9 20.7 16.0 7.4 3.6 12.2 Temp. (Lorain) Total solids 157 157 163 161 167 176 176 181 181 181 172 165 170 Nitrate 1.15 1.15 1.19 1.17 1.21 1.28 1.28 1.32 1.32 1.32 1.25 1.20 1.24 Fluoride.10.10.10.10.10.11.11.11.11.11.10.10.10 Chloride 17.2 17.2 17.8 17.6 18.2 19.2 19.2 19.8 19.8 19.8 18.8 18.0 18.6 Sulphate 23.9 23.9 24.7 24.5 25.3 26.7 26.7 27.5 27.5 27.5 26.1 25.0 25.8 Bicarbonate 108 108 112 110 114 120 120 124 124 124 118 113 116 Sodium plus 9.0 9.0 9.4 9.3 9.6 10.1 10.1 10.4 10.4 10.4 9.9 9.5 9.7 potassium Magnesium 8.1 8.1 8.4 8.3 8.6 9.0 9.0 9.3 9.3 9.3 8.8 8.5 8.7 8.6* 8.6* 9.1* 9.0* 9-3* 9-3* 8.8* 8.7* 8.8* 8.7* 8.6* 8.3* Calcium 34.4 34.4 35.5 35.2 36.3 38.3 38.3 39.5 39.5 39.5 37.5 35.9 37.0 Iron.03.03.04.04.04.04.04.04.04.04.04.04.04 Silica 1.8 1.8 1.9 1.9 1.9 2.0 2.0 2.1 2.1 2.1 2.0 1.9 2.0 Alkalinity 87 87 90 89 92 97 97 100 100 100 95 91 93.7 *Observed magnesium

Year 1952 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 3.2 2.4 2.8 8.0 13.1 20.8 24.5 24.1 21.7 14.8 8.7 5.1 12.4 Temp (Lorain) Total solids 161 157 150 154 161 168 167 172 172 174 176 168 165 Nitrate 1.17 1.15 1.10 1.12 1.17 1.23 1.21 1.25 1.25 1o27 1 28 1.23 1.20 Fluoride o10.10.09.10.10.10.10.10.10.11.11.10 o10 Chloride 17.6 17.2 16.4 16.8 17.6 18 4 18.2 18.8 18.8 19.0 19.2 18.4 18.1 Sulphate 24.5 23.9 22.8 23.4 24.5 25.6 25.3 26.1 26.1 26.4 26.7 25.6 25.1 0 Bicarbonate 110 108 103 105 110 115 114 118 118 119 120 115 113 Sodium plus 9.3 9.0 8.6 8.8 9.3 9.7 9.6 909 9 9 10.0 10ol 9.7 9.5 potassium Magrnesium 8.3 8.1 7.7 7.9 8.3 8.6 8.6 8.8 8.8 8.9 9.0 8.6 8.5 8.3* 8.5* 8,2* 8,3* 9.9* 8.1* 8 2* 8.3* 84* 81* 8.5 8.3* Calcium 35.2 34.4 32.8 33.6 35.2 36.7 36~3 37.5 37~5 37.9 38.3 36.7 36.0 Iron o04.03.03.03 o.04 o04.04.04.04.04.04.o4.04 Silica 1.9 1.8 1.7 1o8 1.9 2.0 1.9 2.0 2.0 2.0 2.0 2.0 1.9 Alkalinity 89 87 83 85 89 93 92 95 95 96 97 93 91 2 *Observed magnesium

Year 1953 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Octo Nov. Dec. Av. Temp.(Avon) 3.6 3.6 4.6 8.2 12.6 19.1 23.5 24.5 21.8 16.7 10.4 4.6 12.8 Temp. (Lorain) Total solids 163 157 157 159 157 161 163 165 167 167 161 165 162 Nitrate 1.19 1o15 1.15 1.16 1.15 1.17 1.19 1.20 1.21 1.21 1.17 1.20 1.18 Fluoride.10.10.10.10 1.10.10. 10. 10.10. 10. 10 Chloride 17.8 17,2 17.2 17.4 17.2 17.6 17.8 18.0 18.2 18.2 17.6 18.0 17.7 Sulphate 24.7 23.9 23.9 24.2 23.9 24.5 24.7 25.0 25.3 25.3 24.5 25 0 24.6 0 Bicarbonate 112 108 108 109 108 110 112 113 114 114 110 113 111 Sodium plus 9.4 9.0 9.0 9.2 9.0 923 9.4 9.5 9.6 9.6 9.3 9,5 9,3 potassium Magnesium 8o4 8.1o 8.1 8.2 8.1 8.3 8.4 8.5 8.6 8.6 8.3 8.5 8.3 8.8* 9.1* 8.8* 9.8* 9.1* 8.8* 8.8* 9.5* 8.5* 8.5* 8.4* 8.5* Calcium 35.5 34.4 34.4 34.8 34.4 35.2 35.5 35.9 36.3 36.3 35.2 35.9 35.3 Iron.04.03.03.04.03.04.04.04.04.04.04.04.04 Silica 1.9 1.8 1.8 1.8 1.8 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 Alkalinity 90 87 87 88 87 89 90 91 92 92 89 91 89,4 *Observed magnesium

Year 1954 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.6 2.8 3.5 9.0 13.2 19.7 23.7 23.6 21.3 16.6 9.1 3.8 123 Temp. (Lorain) Total solids 165 159 154 148 161 161 157 165 167 165 163 161 161 Nitrate 1.20 1.16 1 12 1.08 1.17 1.17 1.15 1.20 1.21 1.20 1.19 1 17 1 17 Fluoride.10.10.09.09.10.10.10.10.10.10.10.10 o10 Chloride 18.0 17.4 16.8 16.2 17..6 17.2 18.0 18.2 18.0 17.8 176 17 Sulphate 25.0 24.2 23.4 22.5 24.5 24.5 23.9 25.0 25.3 25.0 24.7 24.5 24.4 o Bicarbonate 113 109 105 102 110 110 108 113 114 113 112 110 110 Sodium plus 9.5 9.2 8.8 8.5 9.3 9.3 9.0 9o5 9.6 9.5 9.4 9.3 9.2 potassium Magnesium 8.5 8.2 7.9 7.6 8.3 8.3 8.1 8.5 8.6 8.5 8.4 8.3 8.2 8.1* 7.6* 7.7* 8.8* 8.9* 8,1* 8. 3* 8, 4* 8 6* 7 5* 8.2* 8 0*o Calcium 35.9 34.8 33.6 32.4 35.2 35.2 34.4 35.9 36.3 35.9 35. 5 352 35.0 Iron.04.04.03.03.04.04.03.04.04.04.04.04.04 Silica 1.9 1.8 1.8 1.7 1o9 1.9 1.8 1o9 1.9 1.9 1.9 1.9 1.9 Alkalinity 91 88 85 82 89 89 87 91 92 91 90 89 88.7 *Observed magnesium

Year 1955 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) 1.7.9 3.8 8.9 15.7 19.4 24.9 25.7 21.7 16.2 8.1 1.9 12.4 Temp. (Lorain) Total solids 163 159 157 157 161 163 163 163 165 163 161 Nitrate 1.19 1.16 1.15 1.15 1.17 1.19 1.19 119 1.20 1.191.18 Fluoride.10.10.10.10.10.10.10.10.10.10.10 Chloride 17.8 17.4 17.2 17.2 17.6 17.8 17.8 17.8 18.0 17.8 17,7 Sulphate 24.7 24.2 23.9 23.9 24.5 24.7 24.7 24.7 25.0 24.7 24.5 Bicarbonate 112 109 109 109 110 112 112 112 113 112 111 Sodium plus 9.4 9.2 9.0 9.0 9.3 9.4 9.4 9.4 9.5 9.4 9.3 potassium Magnesium 8.4 8.2 8.1 8,1 8.3 8.4 8.4 8.4 8.5 8.4 8.3 9.7* 7,2* 7.5* 8.0* 8.3* 8.7* 9.3* Calcium 35.5 34.8 34.4 35.2 355 35.5 35.5 35.9 35.5 Iron.04.04.03.03.04.04.04.04.04.04.04 Silica 1.9 1.8 1.8 1.8 1.9 1.9 1.9 1.9 1.9 1.9 1.9 Alkalinity 90 88 87 87 89 90 90 go 91 90 89.2 *Observed magnesium

Year 1956 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp,(Avon).8.4 3.2 7.9 12.4 18.9 22.7 23.6 15.7 9.9 4.5 1o.o Temp. (Lorain) Total solids 163 154 157 163 161 161 161 165 168 170 167 168 163 Nitrate 1.19 1.12 1.15 1.19 1.17 1.17 1.17 1.20 1.23 1.24 1,21 1.23 1.19 Fluoride.10.09.10.10.10.10.10.10.10.10.10.10.10 Chloride 17.8 16.8 17.2 17.8 17.6 17.6 17.6 18.0 18.4 18.6 18.2 18o4 17.9 Sulphate 24.7 23.4 23.9 24.7 24.5 24.5 24.5 25.0 25 6 25.9 25.3 25 6 24 8 0 Bicarbonate 112 105 108 112 110 110 110 113 115 117 114 115 112 Sodium plus 9.4 8.8 9.0 9.4 9.3 9.3 9.3 9,5 9.8 9.8 9.6 9,7 97 4 potassium Magnesium 8.4 7.9 8.1 8.4 8.3 8,3 8.3 8.5 8.6 8.7 8.6 8.6 8.4 7.6* 9.2* 8.3* 7,7* 7.1* 8.4* 8,3* 9.2* Calcium 35.5 33.6 34-4 35.5 35.2 35.2 35.2 35,9 36.7 37.1 36.3 36.7 35.6 Iron o04.03 03.04.04.04.04.04.04.04.04.04.04 Silica 1.9 1.8 1.8 1.9 1.9 1.9 1,9 1.9 2,0 2.0 1.9 2.0 1.9 Alkalinity 90 85 87 90 89 89 89 91 93 94 92 93 90.2 *Observed magnesium

Year 1957 Yearly Jan. Feb0 Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp.(Avon) o6.8 3.3 6.8 14.3 18.9 23.3 24.1 21.3 14.7 8.7 3.9 11.7 Temp. (Lorain) Total solids 168 165 163 156 165 148 170 165 168 168 167 167 164 Nitrate 1.23 1.20 1.19 1.14 1o20 1.08 1.24 1.20 1.23 1.23 121 1021 1.20 Fluoride o l0 o.l0 lO.09.10.09 11 0.10.10.10 o10.10.10 Chloride 18.4 18. 0 17.8 17.0 18.0 16.2 18o 6 18.0 18.4 18.4 18. 2 18.2 18.0 Sulphate 25.6 25.0 24. 7 23. 7 25.0 22.5 25.9 25.0 25.6 25.6 25.3 25.3 24.9 o Bicarbonate 115 113 112 107 113 102 117 113 115 115 114 114 112 Sodium plus 9.7 9.5 9.4 8.9 9.5 8.5 9.8 9.5 9.7 9.7 9.6 9.6 9.4 potassium Magnesium 8.6 8.5 8.4 8.0 8.5 7,6 8.7 8.5 8.6 8.6 8.6 8.6 8.4 Calcium 36.7 35.9 35.5 34.0 35.9 32.4 37.1 35.9 36.7 36.7 36.3 36.3 35.8 Iron o 04.04.04. 03.04.03.04.04.04.04.04.04.04 Silica 2.0 1.9 1o9 1.8 1.9 1.7 2.0 1.9 2.0 2.0 1.9 1.9 1.9 Alkalinity 93 91 90 86 91 82 94 91 93 93 92 92 90.7

Part 2. Station at Erie, Pennsylvania

Year 1918 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec~ Av, Temp 1.1 1.4 1.7 3.2 10.6 16.4 20.9 22.9 18.7 14,3 10.2 5.2 10o6 Year 1919 Year ly Jan. Feb. Mar. Apr. May June July Aug Sept. Oc t. Nov. Dec. AvT Temp. 1.4 1.0 2.6 5~7 9.7 13.6 17.2 21.9 20.8 16.6 9.8 2.8 10.3

Year 1920 Yearly Jan. Feb. Mar. Apr. May June July Aug,, Sept. Oct. Nov. Dec. Av. Ratio Temp.! ~0 1.0 1.3 4o2 9.7 13.8 20.7 21o 6 19.9 16.9 9.0 4.7 10.3 Total solids 175 177 173 165 173 177 173 171 173 173 15 13 13 1 Nitrate.41.42.41 ~ 39.41.42.41.40.41.41.41.41.41.04 Chloride 20.4 20.6 20.2 19.3 20.2 20. 6 20.2 20.0 20.2 20.2 ~20.4 20~2 20.2.2 Sulphate 23e6 23.8 23~3 22.3 23.3 23,8 23.3 23,0 23.3 2. 3 332. Bicarbonate 155 157 154 147 154 157 154 152 154 154 155 154 154 1.69 Sodium plus 8.9 9.0 8.8 8.4 8.8 9.0 8.8 8.7 8.8 8.8 8 9 8.8 8.8 potassium Magnesium 9.1 9.2 9. 0 8o 6 9.0 9.2 9.0 8.9 90 90 91 90 90 Calcium 36.8 3 72 n36.4 34.8 36.4 37.2 36.4 36.0 36.4 36.4 68364 64 3686.364.0 Iron.009.009.009.009,009.009.009.009.009.009.009.009.009.01 Silica 1.6 1.6 1.5 1.5 1.5 1.6 1.5 1.5 1.5 1.5 1.6 1.5 1.5 Alkalinity 92 93 91 87 91 93 91 90 91 91 92 91 9. ~*The "ratio" values indicated are the ratio of the parameter in question to alkalinity., i~e., "a parameter/alkal inity. These values apply to years 1920-1956, pages 113-148,

Year 1921 Jan. Feb. Mar. Apr. May June Jul y Aug. Sept. Oct.'Nov. Dec~ v Temp. 1.8 1.0 3. 3 8.4 12.3 16o8 23~9 22.8 22o11l9 9-. Total olids 175 17 171 163 169 173.177 175 179 177 177 177 17 Nitrate.41.42 o 40 ~ 39.40.41.42.41.42.42. 42.42.4 Chloride 20. 4 20. 6 20.0 19.! 19~ 8 20.2 20~ 6 20~ 4 20.9 20. 6 20.6 20~.0 Sulphate 23.6 23~8 23~0 22.0 22.8 23~3 238 36 241 38 238 3Bicarbonate 155 157 152 145 10154 15 5 19 17 17 17 Sodium plus ~~~8~9 9.0 8.7 8.3 8~6 8.8 9.0 8.9 9o1 90l.. potassium.. Magnesium 9.1 9.2 8~9 8.5 8.8 9~0 9~2 9.1 9.3 9~2 9~2 9,29. Calcium 36.8 37.2 36o0 34.4 35~ 6 36. 4 37~ 2 36~ 8 C7 63.2 723. 6 Iron ~ 009 ~ 009.009 ~ 009.009 ~ 009 o 009 o009 ~ 009 o 009.009 -o 09~ 0 Silica 1.6 1.6 1.5 1.5 1.5 1.5 1.6 1o6 1,6 1.6 1.6 1.616 Alkalinity 92 93 go 86 89 91 93 2 94 3 933

Year 1922 Yearly Jan. Feb. Mar. Apr. May June July Aug. Septo Oct. Nov. Dec. Av. Tempo 0~9 0.6 102 6.4 10.2 16.6 21_7 22.1 21.1 160 96 28 8 21.7 16.o ~~9.6 2.8 1o Year 1923 Temp. 0.9 0.4 0~7 2.9 7.6 16o8 19.4 19.7 18.9 15.1 8.3 56 97 Total solids 181 179 179 181 179 177 177 177 179 175 173 175 177 Nitrate. 43 42.42 ~ 43.42.42 o42.42 42.41.41.41.42 Chloride 21.1 20~9 20.9 21.1 20.9 20.6 20.6 20.6 20.9 20.4 20.2 20.4 20.7 Sulphate 24.3 24.1 24.1 24.3 24.1 23.8 23.8 23.8 24.1 23.6 233 236 239 Bicarbonate 160 159 159 160 159 157 157 157 159 155 154 155 18 Sodium plus 9.2 9.1 9.1 9.2 9.1 9.0 9.0 90 9.1 8.9 88 89 91 potassium Magnesium 9.4 9.3 9.3 9~4 9.4 92 9.2 92 93 91 91 92 9.3 9.3 9.2 ~~~~~9.2 9~3 9o1 9.0 9.19~ Calcium 38.0 37 6 37 6 38o0 37.6 37.2 37.2 37 2 37.6 36.8 36 4 368 373 37 37 37 ~~~~~~~~37.6 36. 64 3. Iron.010.0 009.009 0 10. 009 09 009.009 009 009 ~..00 9.00 9 Silica 1.6 1o6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1o 5 1.6 1.6 Alkalinity 95 94 94 95 94 93 93 93 94 92 91 92 933

Year 1924 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 0.2 0.3 0.4 2.1 7.1 13.4 21.3 22.2 18.4 14.9 96 3.4 94 Total solids 175 175 175 177 179 177 173 177 179 179 177 173 176 Nitrate.41.41.41 o 42.42.42.41.42.42. 42.42.41 42 Chloride 20.4 20~4 20.4 20.6 20.9 20.6 20.2 20~6 20.9 20.9 20~6 20.2 20.6 Sulphate 23.6 23.6 23.6 23.8 24.1 23.8 23.3 23.8 24.1 24.1 23.8 23.3 23.7 Bicarbonate 155 155 155 157 159 157 154 157 159 159 157 154 157 1-i Sodium plus 8.9 8.9 8.9 9o.0 9.1 9o.0 8.9 9.0 9o1 9.1 90 8.8 9o potassium Magnesium 9.1 9.1 9.1o 92 9~3 9.2 9.0 9.2 9-3 9~3 9.2 9.0 92 Calcium 36.8 36.8 36.8 37.2 37.6 37.2 36.4 37.2 37.6 37.6 37.2 36.4 371 Iron.009. 009.009. 009.009.009.009.009.009.009.009. 009 009 Silica 1,6 1.6 1.6 1.6 1.6 1.6 1.5 1.6 1o6 1.6 1.6 1.5 1.6 Alkalinity 92 92 92 93 94 93 91 93 94 94 93 91 927

Year 1925 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 0.3 0.4 0~9 4.2 10.0 17.9 20.9 22.2 21.1 13.8 6.4 2.4 10.0 Total solids 173 175 173 173 175 173 171 171 171 173 171 171 173 Nitrate.41.41.41.41.41.41.40.40.40.41.40.40.41 Chloride 20.2 20.4 20.2 20.2 20.4 20.2 20.0 20.0 20.0 20.2 20.0 20.0 20.2 Sulphate 23.v 3 23,. 6 23.v 3 23.3 3 2.6 23.3 23.0 23.0 23.0 23.3 23.0 23.0 23.2 Bicarbonate 154 155 154 154 155 154 152 152 152 154 152 152 153 F-i Sodium plus 8.8 8.9 8.8 8.8 8.9 8.8 8.7 8.7 8.7 8.8 8.7 8.7 8.8 potassium Magnesium 9.0 9.1 9.0 9.0 9.1 9.0 8.9 8.9 8.9 9.0 8.9 8.9 9.0 Calcium 36.4 36.8 36.4 36.4 36.8 36.4 36.0 36.0 36.0 36.4 36.0 36.0 36.3 Iron.009.009.009.009.009 ~009.009 ~009.009. 009.009. 009.009 Silica 1.5 1.6 1.5 1.5 1.6 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Alkalinity 91 92 91 91 92 91 90 90 90 91 90 90 90.8

Year 1926 Yearly Jan~ Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 0~3 0~3 0~3 17 8.7 15.8 19.l 22.8 21.1 16,9 10,3 4.1 10.1 Total solids 171 171 175 177 175 177 177 177 179 175 175 177 175 Nitrate. 40 o40.41 o42.41.42.42.42.42. 41.41.42.42 Chloride 20.0 20.0 20.4 20.6 20.4 20.6 20, 6 20.6 20.9 20.4 20.4 20.6 20.5 Sulphate 23.0 23.0 23.6 23.8 23~6 23.8 23.8 23.8 24.1 23.6 23,6 23.8 23.6 Bicarbonate 152 152 155 157 155 157 157 157 159 155 155 157 156 H-J oo Sodium plus 8.7 8.7 8.9 9.0 8.9 9.0 9.0 9.0 9.1 8.9 8.9 9.0 9.0 potassium Magnesium 8. 9 8.9 9.1 9.2 9.1 9,2 9.2 9.2 9.3 9.1 9 1 9.2 9.1 Calcium 36.0 36~0 36.8 37.2 36.8 37.2 37.2 37.2 37.6 36.8 36 8 37.2 36.9 Iron.009.009. 009. 009.009.009 o009.009.009.009.009.009.009 Silica 1.5 1.5 1.6 1.6 1.6 1o6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 90 90 92 93 92 93 93 93 94 92 92 93 92.3

Year 1927 Yearly Jan. Feb. Maro Apr. May June July Aug. Sept. 0cto Nov. Deco Avo Temp., 2.1 20 206 5.4 11.4 16.7 21.8 22.4 21.2 16.7 11,4 5.8 11.6 Total solids 177 177 179 179 179 181 179 181 182 184 184 184 181 Nitrate.42.42.42.42.42. 43.42. 43 o.43.44.44.44 o 43 Chloride 20.6 20.6 20.9 20.9 20.9 21.1 20.9 21.1 21.3 21.5 21.5 21.5 21. Sulphate 23.8 23.8 24.1 24.1 24.1 24.3 24.1 24.3 24.6 24.8 24.8 24.8 24.3 H Bicarbonate 157 157 179 179 179 160 159 160 162 164 164 14 6 160 1Sodium plus 9.0 9.0 9.1o 91 9.1 9.2 9.1 9.2 9.3 9.4 9.4 9.4 9.2 potassium Magnesium 9.2 9.2 9.3 9,3 9.3 9.4 9.4 9.5 9.5 9.6 9.6 9.6 9.5 Calcium 37.2 37.2 37- 6 37.6 37.6 38.0 37.6 38.0 38.4 38.8 38.8 38.8 38 0 Iron.009.009.009.009.009.010.009..010.00.010 010.010 009 Silica 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 93 93 94 94 94 95 94 95 96 97 97 97 94.9

Year 1928 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Tempo 2.4 1.4 2.0 4.7 10.2 15.3 21.8 22.3 20.2 15.7 10.5 6.0 11.0 Total solids 184 184 184 184 184 184 182 182 184 186 184 184 184 Nitrate. 44. 44. 44. 44. 44.44 43 43 44.44.44.44 44 Chloride 21. 5 21. 5 21o 5 21.5 21. 5 21 5 21 3 21.3 21.5 21.8 21,.5 21.o 5 21 5 Sulphate 24. 8 24 8 24.8 24.8 24.8 24.8 24 6 24 6 24. 8 25.1 24. 8 24. 8 24 8 Bicarbonate 164 164 164 164 164 164 162 162 164 166 164 164 164 o0 Sodium plus 9.4 9.4 9.4 9.4 9.4 9.4 93 9.3 9.4 9~ 5 9.4 9.4 9.4 potassium Magnesium 9.6 96 9. 6 9.6 9o6 9-6 9.6 o.5 9.5 9.6 907 9.6 9.6 9.6 Calcium 38~8 38.8 38.8 38.8 38.8 38.8 38.4 38.4 38.8 39.2 38.8 38.8 388 Iron.010.010.010.010.010.010.010.010.010.010. 010 o.010 010 Silica 1.6 1.6 1o6 1.6 1.6 1.6 1.6 1.6 1.6 1.7 1o6 1.6 1o6 Alkalinity 97 97 97 97 97 97 96 96 97 98 97 97 969

Year 1929 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Tempo 2.1 2.6 2.8 7.8 11.7 17.4 21.6 21.8 20.3 14.4 9.2 3.8 11.3 Total solids 184 184 182 182 179 175 175 177 177 181 181 181 180 Nitrate.44.44.43.43.42.41.41.42.42.43.43.43 43 Chloride 21.5 21.5 21.3 21.3 20.9 20.4 20.4 20.6 20.6 21.1 21.1 21.1 21.0 Sulphate 24.8 24.8 24.6 24.6 24.1 23.6 23.6 23.8 23.8 24.3 24.3 24.3 24.2 Bicarbonate 164 164 162 162 159 155 155 157 157 160 160 160 160 H Sodium plus 9.4 9.4 9.3 9.3 9.1 8.9 8.9 9.0 9.0 9.2 9.2 9.2 9~2 potassium Magnesium 9.6 9.6 9.5 9.5 9.3 9.1 9.1 9.2 9.2 9.4 9.4 9.4 9.4 Calcium 38.8 38.8 38.4 38.4 37.6 36.8 36.8 37.2 37.2 38.0 38.0 38.0 37.8 Iron.010.010.010.010.009.009.009.009.009.010.010.010.009 Silica 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 97 97 96 96 94 92 92 93 93 95 95 95 94.6

Year 1930 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 2.7 2.1 3.1 5.6 12.1 17o5 22.9 22.9 20.9 15.7 9.8 4,9 11.7 Total solids 179 179 175 173 175 175 175 173 173 173 173 175 175 Nitrate.42 o 42 o 41 o 41. 41.41.41 o41 o41.41.41.41.41 Chloride 20.9 20.9 20.4 20.2 20.4 20.4 20.4 20.2 20c2 20.2 20.2 20.4 20.4 Sulphate 24.1 24.1 23. 6 23.3 23.6 23.6 23.6 23.3 23.3 23.3 23.3 23.6 23.6 Bicarbonate 159 159 155 154 155 155 155 154 154 154 154 155 155 Sodium plus 9.1 9.1 8.9 8.8 8.9 8.9 8.9 8.8 8.8 8.8 8 8 8.9 8~9 potassium Magnesium 9.o3 9.v 3 9.1l 9.o0 9.1 9.1 9.1 9.0 9.0 9.0 9.0 9.1 9ol Calcium 37.6 37.6 36.8 36.4 36.8 36.8 36.8 36.4 36.4 36.4 36.4 36.4 36.4 Iron.009.009.009.009.009.009.009.009.009.009.009.009.009 Silica 1.6 1.6 1.6 1.5 1.6 1o6 1 1.5 1.5 1.5 1.5 1.6 1.6 Alkalinity 94 94 92 91 92 92 92 91 91 91 91 92 91.9

Year 1931 Yearly Jan. Febo Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 1.7 1.7 2.1 5.6 10.9 17.2 22.3 23.3 21.9 17.4 12.2 7.3 12.0 Total solids 175 175 173 175 175 173 173 173 173 175 175 175 174 Nitrate 41.41 4.41.41.41. 41.4. 41.41.41 41 Chloride 20.4 20.4 20.2 20.4 20.4 20.2 20.2 20.2 20 2 20.4 20. 4 20.4 20.3 Sulphate 23.6 23.6 23.3 23. 6 23.6 23.3 23.3 23.3 23.3 23.6 23.6 23.6 231 4 Bicarbonate 155 155 154 155 155 154 154 154 154 155 155 155 15 5 Sodium plus 8.9 8.9 8.8 8e9 8.9 8.8 8.8 8.8 8.8 8.9 8.9 8.9 8.9 potassium Magnesium 9.1 9.1 9.0 9.1 9.1 9.0 9.0 9.0 9.0 9.1 9.1 9.1 9ol Calcium 36.8 36.8 36.4 36.8 36.8 36.4 36.4 36.4 36.4 36.8 36.8 36.8 36e6 Iron.009.009.009.009.009.009.009.009.009.009.009 009 Silica 1.6 1.6 1.5 1.6 1.6 1.5 1.5 1.5 1.5 1.6 1.6 1.6 1.6 Alkalinity 92 92 91 92 92 91 91 91 91 92 92 92 91.6

Year 1932 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept.o Oct. Nov. Dec. Avo Temp. 5.7 3.7 3.1 4.6 10.2 16.6 22.1 22.8 21.2 15.6 10.0 5.2 11.7 Total solids 175 173 175 175 173 173 177 179 184 184 182 181 177 Nitrate o41 o.41 o.41 o41.41.41 o.42.42.44.44.43.43.42 Chloride 20.4 20.2 20.4 20.4 20.2 20.2 20.6 20.9 21.5 21.5 21o.3 21.1 20.7 Sulphate 23.6 23.3 23.6 23.6 23.3 23.3 23.8 24.1 24.8 24.8 24.6 24.3 23.9 Bicarbonate 155 154 155 155 154 154 157 159 164 164 162 160 158 RD Sodium plus 8.9 8.8 8.9 8.9 8.8 8.8 9.0 9.1 9.4 9.4 9.3 9.2 9.1 potassium Magnesium 9.1 9.0 9.1 9.1 9.0 9.0 9.2 9.3 9.6 9.6 9.5 9.5.2 Calcium 36.8 36.4 36.8 36.8 36.4 36.4 37.2 37~6 38.8 38.8 38.4 38.0 374 Iron. 009 009 o 009. 009. 009 o 009.009 o 009. 010.010 o.010 o 010 o 009 Silica 1.6 1.5 1.6 1.6 1.5 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1o6 Alkalinity 92 91 92 92 91 91 93 94 97 97 96 95 934

Year 1933 Yearly Jan. Feb. Mar, Apr. May June July Aug. Sept. Oct. Nov~ Dec. Av. Tempn 2.9 2.7 2.7 5.9 12.0 20.4 21.1 22.1 20.7 15.8 y.8 4.7 11.6 Total solids 181 179 179 177 179 177 181 182 184 184 184 184 181 Nitrate. 43.42.42.42.42.42.43. 43 o 44.44.44.44.43 Chloride 21.1 20.9 20.9 20~6 20.9 20.6 21.1 21.3 21.5 21.5 21.5 21.5 21.1 Sulphate 24.3 24.1 24.1 23.8 24.1 23.8 24.3 24.6 24.8 24.8 24.8 24.8 24.4 Bicarbonate 160 159 159 157 159 157 160 162 164 164 164 164 161 Ro \J1 Sodium plus 9.2 9.1 9.1 9.0 9.1 9.0 9.2 9.3 9.4 9.4 9.4 9.4 9.2 potassium Magnesium 9.4 9.3 9.3 9.2 9.3 9.2 9.4 9.5 9.6 9.6 9.6 9.6 9.4 Calcium 38.0 37.6 37.6 36.2 37.6 37.2 38.0 38.4 38.8 38.8 38.8 38.8 38.1 Iron.010.009.009.009.009.009.010.010.010.010.010.010.010 Silica 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 95 94 94 93 94 93 95 96 97 97 97 97 95.2

Year 1934 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Tempo 2.0 1.8 2.9 5.1 11.8 16.6 21.4 22.7 20.5 16.1 9.8 5.6 11.4 Total solids 182 182 181 179 179 177 177 179 179 179 181 18 179 Nitrate.43.43.43.42.42.42.42.42.42.42.43.43.42 Chloride 21.3 21.3 21.1 20.9 20.9 20.6 20.6 20.9 20.9 20.9 21.1 21.1 210 Sulphate 24.6 24.6 24.3 24.1 24.1 23.8 23.8 24.1 24.1 24.1 24.3 24.3 24.2 Bicarbonate 162 162 160 159 159 157 157 159 159 159 160 160 59 R) Sodium plus 9.3 9.3 9.2 9.1 9.1 9.0 9.0 9.1 9.1 9.1 9.2 9.2 9.2 potassium Magnesium 9.5 9.5 9.4 9.3 9.3 9.2 9.2 9.3 93 9.3 9.4 9.4 9.3 Calcium 38.4 38.4 38.0 37.6 37.6 37.2 37.2 37.6 37.6 37.6 38.0 38.0 378 I 37 ~37. 37. 37.6 37.6 38.0 38.0 7 Iron.009.009.010.009.009.009.o009.009.009.009.010.O10.009 Silica 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 96 96 95 94 94 93 93 94 94 94 95 95 94.4

Year 1935 Yearly Jan. Feb. Mar. Apr. May Jtixe July Aug. Sept. Oct. Nov. Dec. Av. Tenip. 2.3 1.7 3- 6 6.7 10.14 17.8 23o.6 214.11 20.3 15.1 11.5 5.1 11.9 Total solids 181 181 181 181 179 175 175 177 179 179 179 177 178 Nitrate ~ 143 ~143 ~143 ~143.142.141.141.142.142.142.142.142.142 Chloride 21.1 21.1 21.1 21.1 20.9 20.14 20.14 20.6 20.9 20.9 20.9 20.6 20.8 Sulphate 214.3 214.3 214.3 214.3 214.1 23.6 23.6 23.8 214.1 214.1 214.1 23.8 214.0 Bicarbonate 160 160 160 160 159 155 155 157 159 159 159 157 158 sodium plus 9.2 9.2 9.2 9.2 9.1 8.9 8.9 9. 91 91 91 90 91 potassium Magnesium9.14 9.14 9.14 9.14 9.3 9.1 9.1 9.2 9.3 9.3 9.3 9.2 9.3 Calcium 38.0 38.0 38.0 38.0 37.6 36.8 36.8 37.2 3. 76 3. 72 3. iron.010.0O10.010.010 ~.009.009.009.009.009.009 ~.009.009.009 Silica 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 95 95 95 95 914 92 92 93 914 914 914 93 93.8

Year 1936 Jan. Feb. Mar. Apr. May June July Aug. Sept. Oc t. Nov. Dec.A( Temp. 2.4 1. 7 2.2 2,7 12.1 17.7 22.4 22.7 21.0 16.1 98 98 3.6 1. Total solids 175 175 1.77 179 i177 11(7 177 179 179 182 182 182 17 Nitrate. 41.41.42.42.42.42.42.42.42.3.3.Chloride 20.4 20.4 20. 6 20. 9 20. 6 20~ 6 20. 6 20. 9 20.9 21~ 3 21.3 21.32. Sulphate 23.6 23~ 6 23.8 24.1 23.8 23.8 23.8 24.1 24.1l 24.6 24.6 24.620 Bicarbonate 155 155 157 15 57 157 157 159 159 i162 162 102 15 Sodium plus 8.9 89 9.0 91 9. 1. 00 potassium 9... Magnesium ~~~~~9~191 92 93 9.2 9.2 9.2 9.3 9~3 9.5 9-595 9.5 Calcium 36~8 36.8 37.2 37. 37. 3723723.63. 37.6 ) f -- 372 37. 37.6 37.6 38.4 38.4 38.4 7. Iron oo9 ~ oo9 oo9 ~ oo9 oo9 oo9 ~ oo9 o oo9 ~ oo9 ~ 010. 010. 010 o Silica 1. 6 1o. ~6 1.6 1.6 1. 6 1.6 1.6 1.6 1.6 1 ~ 6 1.6 1.6 Alkalinity 92 92 93 94 93 3 93 4 946 966

Year 1937 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 4.1 2.6 2.3 6.5 11.7 17.3 22.3 23.9 20.3 14.4 9.2 3.5 11.5 Total solids 177 173 175 179 175 179 181 182 182 184 184 182 179 Nitrate.42.41.41.42.41.42.43.43.43.44.44.43.43 Chloride 20.6 20.2 20.4 20.9 20.4 20.9 21.1 21.3 21.3 21.5 21.5 21.3 21.0 Sulphate 23.8 23.3 23.6 24.1 23.6 24.1 24.3 24.6 24.6 24.8 24.8 24.6 24.2 Bicarbonate 157 154 155 159 155 159 160 162 162 164 164 162 159 1Sodium plus 9.0 8.8 8.9 9.1 8.9 9.1 9.2 9.3 9.3 9.4 9.4 9.3 9.2 potassium Magnesium 9.2 9.0 9-1 9.3 9-1 9-3 9.4 9.5 9.5 9.6 9.6 9.5 9.3 Calcium 37.2 36.4 36.8 37.6 36.8 37.6 38.0 38.4 38.4 38.8 38.8 38.4 37.8 Iron.009.009.009.009.009.009.010.010.010.010.010.010.009 Silica 1.6 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 93 91 92 94 92 94 95 96 96 97 97 96 94.4

Year 1938 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec Av Temp. 2.7 3.3 3.8 8.4 13.3 18.1 22.1 25.2 20.5 16.6 11.3 5.1 12.5 Total solids 179 177 175 167 171 173 177 175 179 181 181 182 176 Nitrate.42.42.41.40.40.41.42.41.42.43 43.43 42 Chloride 20.9 20.6 20.4 19.5 20.0 20.2 20.6 20.4 20.9 21.1 21.1 21. 06 Sulphate 24.1 23.8 23.6 22.5 23.0 23.3 23.8 23.6 24.1 24.3 24.3 24.6 23.8 Bicarbonate 159 157 155 149 152 154 157 155 159 160 160 162 157 o Sodium plus 9.1 9.0 8.9 8.5 8.7 8.8 9.0 8.9 9.1 9.2 9.2 93 90 potassium Magesum Magnesium 9.3 9.2 9.1 8.7 8.9 9o.0 9.2 9.1 9.3 9.4 9.4 9.5 9.2 Calcium 37.6 37.2 36.8 35.2 6 36.4 37.2 36.8 376 38.0 38.0 38.4 371 Iron. 009.009.009.009.009.009.009.009.009.010.010.010. 009 Silica 1.6 1.6 1.6 1.5 1.5 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Alkalinity 94 93 92 88 90 91 93 92 94 95 95 96 928

Year 1939 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 2.8 2.3 2.6 5.3 11.7 18.2 20.9 23o6 21.0 16.3 9.8 6.3 11.7 Total solids 181 177 165 167 169 175 175 175 173 173 173 175 173 Nitrate ~ 43.42 ~ 39.40.40.41.41.41 o 41.41.41.41.41 Chloride 21.1 20.6 19.3 19o5 19.8 20.4 20.4 20.4 20.2 20.2 20.2 20.4 20.2 Sulphate 24.3 23.8 22.3 22.5 22.8 23.6 23.6 23.6 23.3 23.3 23.3 23.6 23.3 Bicarbonate 160 157 147 149 150 155 155 155 154 154 154 155 154 Sodium plus 9.2 9.0 8.4 8.5 8.6 8.9 8.9 8.9 8.8 8.8 8.8 8.9 8.8 po~tasssium Magnesium 9.4 9.2 8.6 8.7 8~8 9.1 9.1 9.1 9.0 9.0 9.0 9.1 9.0 Calcium 38.0 37.2 34.8 35.2 35.6 36.8 36.8 36.8 36.4 36.4 36.4 36.8 36.4 Iron.010.009.009.009.009.009.00 9 ~ 009.009.009.009 Silica 1.6 1.6 1.5 1.5 1.5 1.6 1.6 1.6 1.5 1.5.5 5 1.6 1.5 Alkalinity 95 93 87 88 89 92 92 92 91 91 91 92 91.1

Year 1940 Yearly Jan~ Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec Av. Tempo 2.1 2.2 2.0 3.1 9.2 15.7 21.4 21.5 200 158 10.2 4.9 10.7 Total solids 173 171 171 171 169 171 173 173 175 173 173 171 172 Nitrate. 41 o 40. 40.o40.40.40.41.41. 41 o 41. 41.40 o 41 Chloride 20.2 20.0 20.0 20.0 19.8 20.0 20.2 20.2 20.4 20.2 20.2 20.0 20.1 Sulphate 23.3 23.o0 23.0 23.0 22.8 23.0 233 23.3 23.6 233 23.3 23.0 232 Bicarbonate 154 152 152 152 150 152 154 154 155 154 154 152 153 1Sodium plus 8.8 8.7 8.7 8.7 8.6 8.7 8.8 8.8 8.9 8.8 8.8 8.7 88 potassium Mlagnesium 9.0 8.9 8~9 8.9 8.8 8.9 9.0 9~0 9.1 9.0 9.0 8.9 9~0 Calcium 36.4 36.0 36.0 36.0 35.6 36.0 36.4 36.4 36o8 36.4 36.4 36.0 36,2 Iron.009.009.009.o 009. 009. 009.009.009.009.009. 009. 009.009 Silica 1.5 1.5 1.5 1.5 1.5 1.5 1,5 1.5 1.6 1.5 1.5 1.5 1.5 Alkalinity 91 90 90 90 89 90 91 91 92 91 91 90 905

Ye;-;a r 1 941 Jan. Feb. Mar. Apr. May June July Aug.- Sept. Oct., Nov. Dec. v Temp~ 2.9 2.1 2.4 5.0 12.0 i16.7 20.7 22.7 20.8 16.5 9.9 6.1 1. Total soliOds 1L71 173 171 173 169 171 7 3173 171 173 1"73 1-73 17 Nitrate ~ 40.41 Ao 40 o i. 40 Ao 41.41.40.41 o 41.41 4 Chlo r i'de- 2000 20.2 20.0 2002 19.8 20,0 20.2 20.2 20.0 20.2 20.2 20,22. Sulphate 23. 0 23.3 23~ 0 23.3 22.8 23.0 23.3 23.3 23.0 23. 23.3 23.232 Bicarbonate 152 154 152 154 150 152 154 154 152 154 15;4 154 15 Sodium plus 8.7 8~8 8~7 8.8 8.6 8.7 8.8 8.8 8.7 8~8 8~8 8.888 potassium Magnesium 8.9 9.0 8.9 9.0 8.8 8~9 9~0 9.0 8.9 9~0 9.0 9.090 Calcium 36.0 36.4 36.0 36~ 4 35.6 36.0 36.4 36.4 36.0 36.4 36~ 4 36.43.2 Iron ~ 009.009.009.009 ~ 009.009 ~ 009 ~ 009 ~ 009.009 ~ 009.009 0 silica 1.5 1.5 1.5 1.5 1.5 1.5.5 1.5 1. 5 1.5 1.5 1. 5 1. 5 Alkalinity go 91 90 91 89 go 91 91 90 91 91 91905

Year 1942 Jan. Feb. Mar. Apr. May June Jul y Aug. Sept. Oct. Nov. Dec~ v Temp. 2.1 1.8 2.6 7.4 12.6 14.6 21.9 22.8 209 14 99 3Total solids 171 173 171 169 173 17 13 13 13 13 15 15 Nitrate.40.41 o 40 o 40.41.41.41.41 o 41 o 41.41 o 41 o4 Chloride 20.0 20.2 20o0 19.8 20.2 20.2 20~ 2 20.2 20.2 20.2 20.4 20.42. Sulphate 23.0 23.3 23.0 22.8 23.3 233 33 233 33 21 3 36 23 Bicarbonate 152 154 152 150 154 154 154 154 15 14 5 15 Sodium plus 8.7 8.8 8.7 8.6 8.8 8.8 8.8 8.8 8.8. 89 89 potassium Magnesi um 8. 9.0 8.9 8.8 9.0 9.0 9.0 9.0 9.0 9.0 9.1 9.1 90 Calcium 36~0 36.4 36.0 35~6 36~4 36.4 36.4 36.4 36.4 36.4 36.8 36.8 Iron ~ 009 ~ 009 ~ 009 ~ 009 o 009.009 o 009 ~ 009.009.009 ~ 009 ~ 009 0 Silica 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.6 1.6 Alkalinity 90 91 90 89 91 91 91 91 91 91 92 92

Year 1943 Jan. Feb. M~ro Apr. May June Jul y Auag. Sept. Oct. No~v, Dec,Av Ter;p. o I8 1o7 i~8 4~9 9,8 16.4 23.3 36 20,-l14.. 1 Total solids 173 173 i73 175 1751517 17'7/ 77 7 181!81 1`77 ~ ~ ~ 17 N itrat~e o41,4! o4i Al 41 41 o 41 o 42 42 A2.42 -4 344 ChlIo r ide 20. 2 20~ 2 20o 2 20o 4 20,4 20. 4 20~ 6 20o 6 20. 6 20. 6 21~ Ai 21,1 20I S~,17~h~ate 23 3 2"' 3 23 3 23.6 23.6 23.6 23 8 23.8 23 8 23'4o: 24 32~ Bicarbonate 154 5,4 i54!55 -155 155 1 5 157 157 1 57 1j-60 i 6015 Sod'I'Llmr, p-11-us &8 88 88 89 8.9 8,9 9,10 9-0 9.0 9.0 9~2 9.29~ pol cas s ium Magnesium.0 ~~9.0 9,1 9.1 9.1 9.2 9.2 9,2 9o 2 9o.o4 9- 2 Calcium 36,,4 36 ~,4 36.4 36,8 36,8 36,8 37,2 3.2 3. 80 -8 Iron o009,009 ~ 009,009 ~ 009,009 ~ 009 o 009 o009 o 009 o O10,010 0 Silicea 1.5 1.5 io5 1.6 1.6 1.6 1o6 1.6 1,6 1.6 1.6 1.6 1, Alkalinity 91 91 91 92 92 92 93 3 93 3 955

Year 1944 Yearly Jan. Feb. Nar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 2.1 1.9 2.2 4.3 lO.O 16.7 21.6 21.4 20.0 16.0 ll.1 4.9 lloO Total solids 182 182 177 169 182 184 184 184 186 184 186 182 182 Nitrate ~ 43 ~ 43.42.40 ~ 43.44.44.44.44 o 44.44 ~ 43 ~ 43 Chloride 21.3 21.3 20.6 19.8 21.3 21.5 21.5 21.5 21.8 21.5 21.8 21.3 21.3 Sulphate 24.6 24.6 23.8 22.8 24.6 24.8 24.8 24.8 25.1 24.8 25.1 24.6 24.5 Bicarbonate 162 162 157 150 162 164! 64! 64 166 164 166 162 162 k~ Oh Sodium plus 9.3 9.3 9-0 8.6 9.3 9.4 9.4 9.4 9.5 9.4 9.5 9.3 9.3 potassium Magnesium 9.5 9.5 9~2 8.8 9.5 9.6 9.6 9.6 9.7 9.6 9.7 9.5 9.5 Calcium 38.4 38.4 37- 2 35.6 38.4 38.8 38.8 38,8 39.2 38.8 39.2 38.4 38.3 Iron.010.010.009 ~ 009.010 o 010 o 010.010.0!0.010.010.010.010 Silica 1.6 1.6 1o6 1.5 1.6 1.6 1.6 1.6 1.7 1.6 1.7 1.6 1.6 Alkalinity 96 96 93 89 96 97 97 97 98 97 98 96 95.8

YeICar 1945 Jan. Feb. Mar. Apr. May June Jul y Aug. Sept. Oct. Nov. Dec, v Temp. 1.9 1o9 2.8 9- 6 11.4 14.9 20~ 3 22.3 20.7 15.3 11.2 48 Total solids 184 184 171. 169 171 169 175 181 182 182 184 184 Nitrate.44.44.40.40.40.40.41 4.3.3.4.4 Chloride 21.5 21.5 20.0 19.8 20.0 19.8 20.4 21.1 2o321.325 21.50. Sulphate 24.8 24.8 23.0 22.8 23.0 22.8 23.6 24~ 3 24.6 2. 48 2Bicarbonate 164 164 152 150 152 150 155 160 162 162 164 164 ~~~~~~~~~~Jq~~~~~~~~~~~~~~~~~5 Sodium plus 9.4 9,4 8.7 8.6 8.7 8.6 89 92 93 93 94 4 potassium Magnesium 9.6 9.6 8.9 8.8 8.9 8.8 9.1 94 95 95 96 96 Calcium 38.8 38.8 36.0 35.6 36.o 56 3. 80 384 84 388 8Iron.010.010.009.009.009.009.009.0t0.010.010.010.010 Silica 1.6 1.6 1.5 1.5 1.5 1.5 i.6 1.5 1.5 1.5 1.6 1.6 1. Alkalinity 97 97 90 89 90 8 2 9 6 9 7 9

Year 1946 Jan. Feb. Mar. Apr. May June July Aug. Sept,- Oct. Nov. De c. T emp,. 2.2 1. 9 3. 6 8.3 12.0 16.3 19.7 21~ 3 19, 6 1 6o~8 12.8 6. 1 1 Total Solids 184 182r 177 167 167 169 171 173 171 173 177 171 Nitrate.44 ~43 e 42 4o 4 0 40.40 4o0.41.40,41.42 4o40~4 Chloride 21.5 21,3 20,,6 19o5 19, 5 19~,8 20.0 20,2 20.0 20.2 20. 6 20,0 0. Sulphate 24,,8 24. 6 23,5.8 22,5 2!2,5 22. 8 23.0 23, 3 23.0 23, 3 23,8 23,0 Bicarbonate 164 162 157 149 149 lpO 152 154 152 154 157 152 u~ Sodium plus 9.4 9.3 9"o0 8op5 8o5 8,6 8.7 8o8 8, 7 8. 8 9. 0 8 7 8 co potass ium.. Magnesium 9,6 9-~5 9,2 8~7 8,7 8,8 8,9 9.. 90927,. Calcium 38.8 38.4 3 7235,2 35.2 35.6 36.0 36.4 36.0 36.4 37236.0 6, Iron,010 ~ 010. 009.009.009.009.009,009 o 009 o 009.009,009 0 Silica i 1 6 1,6 1o 6 1,5 1~ 5 1.5 1,p 1.5 1. 5 1.5 1, 6 1.51. Alkalinity 97 96 93 88 88 89 90 91 90 91 93 90913

Year 1947 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 2.8 2.2 2.4 4.2 10.7 15.8 18.8 22.2 22.3 17.7 12.3 4.8 11.4 Total solids 169 165 171 165 163 171 171 165 165 165 165 167 167 Nitrate.40.39.40.39.39 40.40 39.39 39.39.40 40 Chloride 19.8 19.3 20.0 19.3 19.1 20.0 20.0 19.3 19.3 19.3 19.3 19.5 19.5 Sulphate 22.8 22.3 23.0 22.3 22.0 23.0 23.0 22.3 22.3 22.3 22.3 22.5 22.5 Bicarbonate 150 147 152 147 145 152 152 147 147 147 147 149 148 Sodium plus 8.6 8.4 8.7 8.4 8.3 8.7 8.7 8.4 8.4 8.4 8.4 8.5 8.5 potassium Magnesium 8.8 8.6 8.9 8.6 8.5 8.9 8.9 8.6 8.6 8.6 8.6 8.7 8.7 Calcium 35.6 34.8 36.0 34.8 34.4 36.0 36.0 34.8 34.8 34.8 34.8 35.2 35.2 Iron.009.009.009.009.009.009.009.009.009.009.009 009.009 Silica 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Alkalinity 89 87 9 87 86 90 90 87 87 87 87 88 879

Year 1948 Yearl y Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 2.1 2.0 3.3 8.2 11.8 16.5 20.2 22.7 22.7 15.6 11.3 6.4 Total solids 175 171 167 167 163 169 169 171 171 173 173 173 170 Nitrate.41.40.40.40 ~ 39.40.40.40.40.40.40.40.40 Chloride 20.4 20.0 19o 5 19.5 19.1 19.8 19.8 20.0 20.0 20.2 20.2 20.2 Sulphate 23.6 23.0 22.5 22.5 22.0 22.8 22.8 23.0 23.0 23.3 23.3 23. Bicarbonate 155 152 149 149 145 150 150 152 152 154 154 154 0 Sodium plus 8.9 8.7 8.5 8.5 8.3 8.6 8.7 8.7 8.7 8.8 8.8 8.8 8.7 potassium Magnesium 9.1 8.9 8.7 8.7 8.5 8.8 8.8 8.9 8.9 9.0 9.0 9.0 8.8 Calc~ium 36.8 36.0 35.2 35.2 34.4 35.6 35.6 36.0 36.0 36.4 36.4 36.4 Iron.009.009. 009.009. 009.009. 009.009 ~009 ~009. 009 ~00 ~ Silica 1.6 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Alkalinity 92 90 88 88 86 89 89 go 90 91 91 91

Year 19)49 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 3.2 2.3 3.0 6.8 11.9 18.11 20.1 2)4.3 18.6 17.2 11.7 4.11 11.8 Total solids 171 169 167 167 173 175 173 173 175 175 175 175 172 Nitrate.40 ~ 40,40.140.4]..)41.411.411.41.41.411.411.41 Chloride 20.0 19.8 19o.5 19.5 20.2 20.4 20.2 20. 2 20.4 20.4v 20.4 20.11 20.1 Sulphate 23.0 22.8 22.5 22.5 23.3 23.6 23.3 23.3 23. 6 23.6 23.6 23.6 23.2 Bicarbonate 152 150 149 1)49 15)4 155 15)4 15)4 155 155 155 155 153 H Sodium plus 8.7 8.6 8.5 8.5 8.8 8.9 8.8 8.8 8.9 8.9 8.9 8.9 8.8 potas sium Magnesium 8.9 8.8 8.7 8.7 9.0 9.1 9.0 9.0 9.1 9.1 9.1 9.1 9.0 Calcium 36.0 35.6 35.2 35.2 36.11 36.8 36.4 36.4 36.8 36.8 36.8 36.8 36.3 Iron.009 ~.009 ~.009.009.009.009.009.009 ~.009.009 ~.009.009.009 Silica 1.5 1.5 1.5 1.5 1.5 1.6 1.5 1.5 1.6 1.6 1.6 1.6 1.5 Alkalinity 90 89 88 88 91 92 91 91 92 92 92 92 90.7

Year!950 Yearly Jan. Feb.o Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 5-3 3.1 2.6 4.9 9.6 16.8 20.3 22.5179 6. 109 39 12 Total solids 171 171 171 169 167 169 16 19 19 17 3 11 10 Nitrate. 40. 40. 40. 40. 40. 40. 40. 40. 40. 41. 41. 40. 40 Chloride 20.0 20.0 20.0 19.8 19.5 19.8 19.8198 9. 204 02 2.0 99 Sulphate 23.0 23.0 23.0 22.8 22.5 22.8 22.8 22.8 22.8 236 3. 2.0 30 Bicarbonate 152 152 152 150 149 150 150 150 150 15 14 12 12 Sodiu plus 8.7 8.7 8.7 8.6 8.5 8.6 8.6 8.6 8.6 8.9 8.8 8.7 8.7 potassium Magnesium 8.9 8.9 8.9 8.8 8.7 8.8 8.8 8.8 8.8 9. 90 89 89 Calcium 36.0 36.0 36.0 35.6 35.2 35.6 35.6 35.6 35.6 36.8 3. 60 3. Iron ~ 009 ~ 009 ~ 009 ~ 009 ~.009 ~009 ~009 ~009.009 ~009 ~009 ~o 00 ~00 Silica 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.6 1.5 1.5 1.5 Alkalinity 90 90 90 89 88 89 89 89 89 92 91 90 8.

Year %951l Jan, Feb. Mar. Apr. May June Jul y Aug. Sept. Oct. Nov. Dec, Av. Temp. 2,4 1.8 2.2 6.5 11.2 15,7 21,6 22.8 20.3 15.2 9.6 4.5 Total solids 169 167 169 173 169 173 167 171 171 171 171 171 170 Nitrate.40.40.40.41,40.41.40.40.40.40.40.40.40 Chloride 19.8 19.5 19.8 20,2 19.8 20.2 19.5 20,0 20,0 20.0 20,0 20,0 Sulphate 22.8 22.5 22.8 23.3 22.8 23.3 22,5 23.0 23,0 23.0 23.0 23.0 22.9 Bicarbonate 150 149 150 154 150 154 149 152 152 152 152 152 SodiuP1 plus 8.6 8.5 8.6 8.8 8.6 8.8 8.5 8.7 8.7 8.7 8.7 8.7 8.7 pots sium potasiu MagneSium 8.8 8.7 8.8 9.0 8.8 9.0 8.7 8.9 8.9 8.9 8.9 8.9 8.9 CalciUm 35.6 35.2 35.6 36.4 35.6 36.4 36.2 36.0 36.0 36.0 36.0 36.0 ron.~009.009 ~009 009 ~009 ~ 009.009.009.009.009. c9,00 oo Silica 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Alkalinity 89 88 89 91 89 91 88 90 go go go 90 89.6

.L4=~~~~~~~~~~~~~~~~~~~~~~Yarly95 Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. v Temp. 2.6 2.6 3.1 6.2 5.6 17.1 22.2 22.8 20. 6 14.6 lo. 6 53 l Total solids 169 169 1.71 167 165 165 169 19 19 17 1 6 Nitrate.40.40.40 0 -~~~~39 ~ 39.40.40.40.40 -39 - 39.4 Chloride 19.8 19.8 20.0 22~5 22.3 22.3 22.8 22.8 22.8 225 23 22 Bicarbonate 150 150 152 149 147 147 150 150 150 14 17 17 Sodium plus 8.6 8.6 87 5 84 84 86 86 86 85 84 84 potassium... Magnesium 8.8 8.8 8.9 8.7 8.6 8.6 8.8 8.8 8.8 8.7 8.6 8.68. Calcium 35.6 35.6 36.0 3.2 3.838 35 34.8 34358 35.6 ~56 35.6 35.2 34.8 34.83. Iron ~ 009 ~ 009 ~ 009 ~ 009 ~ 009 ~ 009.009 ~ 009 ~ 009 ~ 009 o 009 ~ 009 00 Silica 1.5 1o5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.51. Alkalinity 89 89 90 88 87 87 89 89 89 88 877

Year 1953 Yearly Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 2.9 2.]. 3.8 7.3 10.7 16.2 21.6 22.6 20.7 16.2 11.8 6.8 11.9 Total solids 165 163 165 163 173 175 173 181 181 181 181 175 173 Nitrate.39.39.39.39.41.41.41.43.43.43.43,41.41 Chloride 19.3 19.1 19.3 19.1 20.2 20.4 20.2 21.1 21.1 21.1 21.1 20.4 20.2 Sulphate 22.3 22.0 22.3 22.0 23.3 23.6 23.3 24.3 24.3 24.3 24.3 23.6 23.3 Bicarbonate 147 145 147 145 154 155 154 160 160 160 160 155 154 Sodium plus 8.4 8.3 8.4 8.3 8.8 8.9 8.8 9.2 9.2 9.2 9.2 8.9 8.8 potassium Magnesium 8.6 8.5 8.6 8.6 9.0 9.1 9.0 9.4 9.4 9.4 9.4 9.1 9.0 Calcium 34.8 34.4 34.8 34.4 36.4 36.8 36.4 38.0 38.0 38.0 38.0 36.8 36.4 Iron.009.009.009.009.009.009.009.010.010.010.010.009.009 Silica 1.5 1.5 1.5 1.5 1.5 1.6 1.5 1.6 1.6 1.6 1.6 1.6 1.5 Alkalinity 87 86 87 86 91 92 91 95 95 95 95 92 91.0

H ) 0 ON O)'a H H * H H \1 co CO L\ 0 * \10 CY) o. t-: 4 r( CU r- co C) C') r - co CY c) cO ON _:t L(N \ N * * _t -Z \- 0 t: j 0 CY) ON Cm — T * - 0 tQ3'~o H H O rH C C) C o CO * 3- ~ CY) C O ON * Lr\ ON \ * - \-.D 0 tLr O H-4 \OD CY') ON 04 zt * _ 0 tH rH r4 C0 rH co C) CY) * H CO * 0CY) C') CO ON LC\ ON * - -_ \ 0 L I)I-'DO CY') ON 04j _: * -: 0 t0 H H Ct H —4 CGO CO C') H cO 4; - Cv ) (') CO ON\ P. * U\ ON * * - \10 t0 LrN C UN Un 04 ON b t~- 0 * O \ tA 0 UN\ o (CY) \-O - ON 04j zT 8 8 0 COD < 04j HH 04 H- CO) co CY') H CO Cr, H ~~~~CY) (') cO ON r t * \N ON * * ~T t 8 t04 \FO L P) N 0 0 c 04 H r-4 C04 H CO CO () * H CO UN01\d~~ o 04 CON'CO Cd C 9j \:, co r-4 f-4 r-4 r-4 co, o.Y o - co b H- * H~ 04 O C v CO u ON CO \0 ON 0,\ 01\ 0 a 0 co o 0 u'\ ON ON ON 0 CO ~ 0 t \. * - - ON 0 U co 0. O C y) rH rH 04f H CO CO(oo) CO Co ao o~ 6\~~~ ~; oJ tne-. CC) co8 CO ON m,j L -\'0 \ * 0 ON Pt, C ~ r-4 r-t Od r C CC co CY') r,- CC 0 0 0YdC C' 01\ CY')O C~jO- C\ ON -r\ tC oO P. 04 H * 0\ C O'8 H C 8 ~ ~~ (10 03 ONu ON 8d'4 0 0 b )0 0 CO CC) * H ON ~rt ot3 5r r-4 Un 0 0) 0) F P~r4:ON to 0 rd 4~ 0 to'H ~Hd +'d' H C d gko t'H'H OP. cr3'H E-i E) O C) CO PQ COkC 146

r3 Ht H 0 -- t ON 4 - ON ~L( ~-t L! * 0 Lr ~ \H 0 CY) ON C -, * z \ * ON co 0 N t ~~ c>cf J z 8 cf ci CC) CQ CC) 0 _:t O j — I- 00t a)C3\ C) C) -t r- Ll CO, —1 CO * — r-I CC co - r-I co H CO ~ CV 0CO ~ ~~ 0 ON 4 CM cO * - CM % ~ 0 u\10 CY' co zi -- 4 4 - 0 * LP,\;04 ON J -' HI ~ I cO co CY ~ H1 CO 0 Lr\rH 0 ~ ON 4-) * CY) O uN CY LC\ * 0 Lr\ \'0 \0 CY) ON CMj — t * *0 \'0 o H H H CM H CO) CC) O CY) CO D -,o L,\ CMc O N P4 *1 0 O 0 L 0) 0'0 - CM _f LfN 0 0C O CM H * H CM r-H co cO CY * H CO *~.. H~ ~ C. Y) CY) co~ O t ~ O ai 0 ifON O0 Lr\ CM \'0 CY' ON CM * 0 i - <~CM H- r-H CM H- CO) co CY) * H CO) r-4' 0 — J ON CY) ON *-I L(N CY LC 0 I C \ \0 CoO ON CM -: _:t 0 \ 0 FH r-H CMj H- co CO) CY) rH CO 0)co CY CY CO O 0 ~ ~tD- _t \0 ~ 0 LCN tn (X ~*- O *u - H- H- H CM H CO) co CO * H CO'0 0 -~ cON * CY N LC CY') LC\ 0 L\ CY H CY') Cj COC, *HCO (r; 03 o; od 03 M c- co o Y r-4 co H-q 0 _:t ON CM C) ON * Ll\ Cy-) UN0 L lN p4 \'0 CY) O CM _zf * —. 0 * \'0 H- 0 _i O CN Cy- tr\ * 0 LC\ \I C' M O -4 9 0 0 \'0 Hu *- Hf CM H CC CO3 * C C' CY CO'ON g H Lf\ ON\ * t- d \0 * 0 Ir\ 0)o' C O CM _t - 0 r% CMj H- * H CMj H- CO co Cy * H CO) \'0 L\'0 CO CY ) coCM CY) Cy; 0 C 2' c o_:b CY) H * 4 H- co co CO r-H CO) to rd UNr~ H 3 UN\ Q 0 0) P1 ~r4 ON t a) Id 4- 0 co H H-4 4 Hj Cd t to 0 0 -4 0 a) 147

Year 1956 Yearly Jan. Feb. Mar. Apr~ May June July Aug. Sept. Oct. Nov. Dec. Av. Temp. 1.8 1.1 1.5 4.6 lO. 5 15.9 19o8 21-9 98 11 10 4 0. Total solids 169 171 171 167 165 163 163 16 19 7 19 19 18 Nitrate.40.40 *40 *40 *~~39 ~ 39 ~ 39 ~ 39 o 40.40.40.40.40 Chloride 19.w8 20.*0 20.0 19.*5 19.*3 19.*1 19.*1 19'1 19.~8 20.~0 19.e8 198 96 Sulphate 22.*8 23.~0 23.*0 22.v5 22.*3 22.v0 22.*0 22.e0 22.*8 23.*0 22.~8 22.*8 22.*6 Bicarbonate 150 152 152 149 147 145 145 145 150 152 150 150 14'FX~~~~~~~~~~~~~~~~~~~~~~~~~~4 Sodium lus 806 8.7 8.7 8.5 8.4 8~3 8~3 8.3 8.6 8~7 8~6 8.6 8~6 potassium Magnesium 8.8 8.9 8~f9 8.7 8.6 8. 85 85 8 89 88 88 87 Calcium 35.f6 36~0 36.0 35.2 34.8 34.4 34~4 234.4 35.6 36.0 35.6 35.6 35-3 Iron. 009 ~ 009 ~ 009 o 009 ~.009.009 ~009 ~009 ~009 o009 ~009 ~009.009 Silica 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1o5 1.5 Alkalinity 89 90 90 88 87 86 86 86 89 90 89 89 88.3

APPENDIX II LIMNOLOGICAL OBSERVATIONS Data of the Fisheries Research Laboratory of the University of Western Ontario. Published with express permission.

1947 and 1948 STATION I (42'12.0', 81~54.0') Depth 1947 1948 in Feet 8/8 8/13 8/21 8/28 9/14 9/27 10/17 12/3 4/15 4/23 5/6 7/8' 7/20 7/28 8/6 9/9 Water Temperature,'C Surface 23.8 25.0 26.8 25.9 23.7 16.4 18.3 6.0 3.0 4.7 10.0 19.3 23.5 20.7 18.3 22.0 15 23.2 24.2 25.7 25.6 23.7 16.3 17.3 19.7 18.1 30 14.5 18.6 22.9 25.2 22.9 16.3 17.1 6.2 13.6 18.9 11.3 17.9 Bottom 12.7 13.6 15.1 14.3 13.6 16.2 15.7 6.4 3.6 4.0 8.0 12.2 11.0.17.6 22.0 Dissolved Oxygen, ppm Surface 6.1 7.2 6.3 6.7 7.2 8.0 8.8 14.6 11.6 10.6 8.2 7.7 8.0 8.6 30 7.2 7.5 8.5 8.3 4.2 7.9 8.1 Bottom 7.1 6. 6. 6.7 6.3 7.7 14.6 11.5 11.6 4.2 4.1 5.6 7.3 Free Carbon Di-oxide, ppm Surface 0.0 0.0 0.0 0.0 8.8 0.0 0.0 30 2.2 1.8 17.6 8.8 0.0 Bottom 3.5 1.5 2.6 0.8 0.0 0.0 1.3 17.6 17.6 0.0 Methyl Orange Alkalinity, ppm CaC03 Surface 58 95 94 100 100 56 104 100 102 100 109 84 103 30 104 100 100 107 111 115 105 Bottom 58 110 96 100 57 104 100 112.u 115 114 124 Phenolphthalein Alkalinity, ppm CaCO3 Surface 3.0 1.6 4.0 4.0 5.0 0.0 0.0 8.0 6.0 30 0.0 0.0 0.0 3.0 Bottom 4.0 4.0 0.0 0.0 0.0 3.0 pH Surface 8.2 8.0 8.1 8.1 7.7 7.8 8.2 7.7 8.0 8.1 8.2 8.0 8.0 8.5 30 7.7 7.6 7.7 7.8 7.9 8.0 7.9 8.0 8.5 Bottom 7.4 7.6 7.8 7.3 7.4 7.8 7.8 7.8 8.1 7.6 8.0 8.0 8.5 Secchi Disc, feet 23 25 13 150

1949, 1950, and 1951 STATION 1 (42'12.0', 81'54.0') Depth 1949 1950 1951 Feet 6/19 7/12 7/20 8/4 8/23 5/29 6/7 8/26 9/1 11/5 5/30 6/28 7/18 8/2 8/28 Water Temperature, ~C Surface 20.1 24.0 27.8 24.7 23.3 15.2 16.3 20.2 23.3 11.5 13.0 19.7 20.1 21.4 23.5 21.7 15 18.8 23.8 24.2 24.6 23.2 11.9 12.2 19.0 21.3 30 17.1 23.8 23.9 22.9 10.0 8.1 20.0 21.9 11.3 17.0 18.7 17.5 23.3 21.3 Bottom 16.1 253.4 14.6 22.5 22.7 9.0 8.0 10.8 11.2 11.5 9.7 15.2 10.8 11.9 10.8 11.3 Dissolved Oxygen, ppm Surface 9.6 8.1 7.6 8.3 11.7 11.0 8.4 9.7 11.2 9.6 9.2 9.3 30 9.5 8.4 8.0 8.0 11.6 11.0 8.4 10.8 10.7 9.3 8.9 Bottom 8.0 7.9 6.4 7.9 10.9 10.8 7.6 9.6 10.8 9.3 8.3 4.5 Free Carbon Dioxide, ppm Surfade 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 8.8 5.3 1.8 0.0 30 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.0 0.0 3.5 2.6 0.0 Bottom 0.0 2.0 3.0 2.5 0.0 0.9 1.3 2.6 2.6 0.0 7.1 7.0 4.0 2.7 Methyl Orange Alkalinity, ppm CaC03 Surface 108 90 116 114 116 111 98 106 103 105 108 107 108 105 30 104 110 114 110 116 122 110 106 104 109 108 102 Bottom 100 106 114 114 116 116 112 114 107 100 120 108 109 110 Phenolphthalein Alkalinity, ppm CaCO3 Surface 4.0 4.0 5.0 5.0 5.0 3.0 1.0 2.0 2.5 2.5 0.0 0.0 0.0 0.0 3.0 30 4.0 2.0 3.0 4.0 4.0 0.5 0.0 1.0 2.0 0.0 0.0 2.0 Bottom 2.0 0.0 0.0 0.0 3.0 0.0 0.0 0.0 0.0 2.0 0.0 0.0 0.0 0.0 PH Surface 8.0 8.1 8.3 8.2 8.5 8.0 8.1 8.2 8.4 8.2 7.8 8.1 8.0 8.4 30 7.9 8.1 8.0 8.1 8.5 8.0 8.0 8.0 8.4 8.1 7.9 8.3 Bottom 7.8 7.9 7.8 7.7 7.8 7.8 7.5 7.5 8.1 7.8 7.7 7.5 7.9 Secchi Disc, feet 11 15 18

1952 STATION 1 (42~12.0', 81~54.0') Depth 1952 in Feet 6/4 6/12 6/17 6/27 7/5 7/7 7/14 7/16 7/22 7/24 7/29 8/7 8/19 8/30 9/5 Water Temperature, ~C Surface 14.7 11.7 19.3 18.3 21.9 21.9 23.4 22.9 24.3 20.3 24.1 23.4 23.3 23.6 21.5 15 13.9 10.8 16.4 17.9 21.1 21.2 23.2 21.8 22.5 20.1 23.2 23.0 23.1 23.3 20.6 30 13.0 10.5 13.0 15.5 19.9 20.2 21.3 19.6 11.9 11.4 22.2 22.5 22.6 22.,9 19.7 Bottom 9.9 10.5 10.5 12.7 12.7 13.0 10.8 11.0 10.2 10.2 10.8 11.4 16.1 12.5 12.6 Dissolved Oxygen, ppm Surface 9.2 10.1 6.2 8.9 8.5 7.4 7.9 7.8 8.0 8.7 8.7 9.6 9.7 30 9.7 8.6 10.4 9.0 8.7 8.0 7.8 7.6 7.8 7.8 8.6 8.5 9.4 9.2,Bottom 7.8 9.9 9.7 8.8 7.5 7.0 6.9 7.7 6.9 7-0 8.4 8.4 6.7 8.6 Free Carbon Dioxide, ppm Surface 3.2 3.3 2.0 0.0 0.0 0.0 1.0 2.3 4.3 0.0 0.0 0.0 4.0 30 2.0 3.0 1.3 1.3 0.0 2.0 3.3 2.0 2.6 2.0 0.0 0.0 0.0 5.3 Bottom 2.0 2.0 1.7 2.0 2.3 3.0 2.6 5.0 4.3 3.6 0~ ~ 3.6 6.9 Methyl Orange Alkalinity, ppm CaC03 Surface 114 114 118 117 105 103 103 108 96 98 105 102 105 99 30 110 118 114 111 106 o109 97 109 101 98 99 lo09 108 91 Bottom 112 116 110 109 115 123 69 108 102 109 99 101 113 94 Phenolphthalein Alkalinity, ppm CaCO3 Surface 0.0 0.0 0.0 ~ 0.0 15 3.0 0. 0.. 1.5 0.0 7.5 4.5 0.0 30 0. 0 0. 0 0. 0 0.0 2.5 0.0 0.0 0.0 0.0 0.0 8.0 5.0 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 7.0 0.0 0.0 pH Surface 8.1 7.8 8.2 8.0 8.0 8.2 8.0 8.0 7.3 7-7 8.3 8.4 8.4 7.8 30 7.9 7.6 8.0 8.2 8.2 8.1 7.9 7.8 7.8 8.2 8.0 8.2 7.8 Bottom 7.8 7.7 7.7 7.9 7.9 7.9 7.0 7.7 7.4 7 5 8.3 8.2 8.o 7.8 152

1953 STATION 1 (42'12.o', 81~ 54.' ) Depth 1953 in Feet 6/2 6/10 6/15 6/29 7/3 7/9 7/15 7/30 8/6 8/13 8/24 8/25 8/31 9/1 9/8 9/14 Water Temperature, ~C Surface 13.5 15.4 16.0 21.0 18.4 20.7 23.6 22.8 22.4 23.1 23.3 23.9 25.3 26.3 21.5 17.1 15 12.5 14.7 15.4 19.8 17.4 19.1 23.4 22.8 22.4 22.5 23.0 23.3 25.4 21.5 16.9 30 12.0 14.0 14.8 18.8 16.2 14.2 20.3 16.2 22.2 22.5 22.8 23.0 22.9 23.5 21.5 16.7 Bottom 11.8 10.6 11.4 11.8 11.4 11.3 11.5 11.1 20.4 14.5 12.6 12.7 12.7 13.5 15.2 15.3 Dissolved Oxygen, ppm Surface 10.5 9.4 9.6 8.9 8.9 8.9 8.7 8.6 8.3 8.7 8.6 8.6 7.9 8.3 7.5 6.5 30 10.2 9.7 9.1 9.0 8.2 8.7 8.4 7.1 10.3 8.4 8.4 8.0 7.5 6.1 Bottom 9.2 9.8 9.1 8.8 8.4 8.4 7.5 7.2 10.8 5.2 3.5 3.2 2.2 2.0 2.4 5.1 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.0 30 0.0 0.0 0.0 0.0 1.0 0.0 1.0 0.0 0.0 0.0 0.0 1.0 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 2.0 4.0 3.0 0.0 3.0 0.7 5.5 0.5., 6.0 7.0 4.0 Phenolphthalein Alkalinity, ppm CaC03 Surface 8.0 5.0 5.0 2.8 2.7 2.0 3.0 4.0 4.8 4.5 5.0 5.5 4.0 4.2 0.8 0.0 30 2.5 2.5 2.0 1.8 0.0 1.5 o.0 352 5.5 2.7 3.3 0.0 0.0 Bottom 8.0 2.5 2.5 0.7 1.1 0.0 1.0 0.0 1.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 pH Surface 8.0 7.8 8.0 8.0 8.1 8.o 8.4 8.4 8.4 8.4 8.4 8.4 7.8 7.5 30 8.2 7.8 7.9 8.i 8.0 7.6 8.4 8.4 8.4 8.4 7.8 7-5 Bottom 8.1 7.8 7.8 7.6 8.0 7.8 7.8 7.6 7.5 7.6 7.4 7.5 7.5 7.4 Secchi Disc, feet 2 12 26 27 27 16 21 14 10 26 34 31 15 13 7 153

1947 and 1948 STATION 2 (420 07.2', 81~ 53.9') Depth 1947 1948 in Feet 7/28 8/8 8/13 8/21 9/13 9/27 4/23 6/4 6/19 7/8 7/31 8/13 8/26 8/30 9/9 Water Temperature, C Surface 22.1 24.1 25.0 26.8 23.8 17.3 4.6 14.7 15.5 18.6 22.7 20.9 25.1 24.4 22.7 30 20.9 17.2 23.4 18.8 23.7 16.9 4.4 10.7 14.2 18.2 22.7 23.2 23.8 23.1 45 20.9 11.5 12.2 12.6 23.4 16.6 17.0 22.5 20.7 22.0 22.4 23.0 Bottom 10.5 11.0 10.8 ll. 9 12.7 14.5 4.4 10.2 12.6 11.0 11. 11.1 11.4 15.2 17.0 Mean 18.6 16.9 18.3 19.0 21.2 16.4 4.5 11.7 14.8 17.2 22.1 21.0 23.1 21.6 Mean of Epilimnion 21.2 23.4 24.4 25.4 235.7 18.1 22.6 23.7 25.7 Epilimnion Dissolved Oxygen, ppm Surface 9.8 11.0 9.4 8.2 8.2 7.5 7.9 8.0 30 8.5 7.0 7.4 7.3 6.3 9.8 11.2 8.1 8.2 8.o 3.1 8.0 45 7.9 6.5 7.7 10.2 9.5 8.o 6.2 3.1 8.1 Bottom 7.0 6.9 6.6 7.8 5.0 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 50 0.0 0.0 0.0 0.0 0.0 0.0 0.0 30 o.o o.o o.o o.o o.o o.o o.o 45 0.0 o.o 0.o 1.3 o.Q 0.0 o.0 Bottom 6.4 0.0 1.8 0.0 1.3 22.1 46.2 1.8 Methyl Orange Alkalinity, ppm Ca C03 Surface 115 96 100 io6 105 98 104 102 110 104 103 30 97 100 105 98 104 107 104 102 45 150 100 96 98 102 106 109 106 105 Bottom 150 100 100 107 117 106 98 108 117 106 93 Phenolphthalein Alkalinity, ppm CaCO3 Surface 1.5 3.0 5.0 4.0 2.4 4.0 4.o 9.0 7.0 4.0 350 3.0 14.0 5.0 2.0 11.0 6.0 6.0 45 3.0 4.0 3.6 3.6 0.0 2.0 3.0 6.0 Bottom 0.0 1.0 2.0 0.0 2.0 0.0 0.0 0.0 0.0 pH Surface 8.o 8.1 8.2 8.o 8.o 8.3 8.4 8.4 8.o 8.2 8.3 8.3 8.5 30 8.o 7.9 7.9 8.5 8.4 8.2 8.o 8.3 8.5 45 7.4 7.4 8.4 8.4 8.o 7.3 8.0 8.5 Bottom 7.5 7.3 7.4 7.4 7.9 8.3 7.7 8.o 7.4 7.2 7.3 7.5 Secchi Disc, feet 25 19 25 25 11 154

1949 STATION 2 (42' 07.2', 81' 53.9') Depth 1949 in Feet 6/10 6/19 6/27 7/6 7/12 7/20 7/28 8/4 8/10 8/23 9/7 9/15 Water Temperature,'C Surface 15.2 20.4 23.2 26.2 22.0 24.0 25.5 25.0 26.0 23.2 20.7 19.2 30 14.6 16.4 16.3 20.1 21.8 22.8 24.5 24.2 24.7 23.0 20.8 19.4 45 14.4 12.7 12.4 12.4 21.5 22.3 22.5 23.6 24.1 22.4 20.6 19.2 Bottom 11.3 11.1 10.0 11.2 12.2 12.4 11.4 12.5 12.0 12.5 19.4 18.4 Mean 14.3 15.9 16.5 19.4 20.4 21.1 21.6 22.3 22.9 21.3 20.0 19.2 Mean of Mean of 22.6 25.6 21.7 22.9 24.4 24.3 25.7 23.0 Epilimnion Dissolved Oxygen, ppm Surface 9.5 10.2 9.6 8.3 8.8 8.6 9.2 8.7 8.3 8.6 8.1 8.1 30 9.5 9.3 8.5 8.o 8.4 8.4 8.8 9.1 7.5 8.2 7.4 45 9.0 9.9 8.o 8.o 8.5 8.6 8.4 8.7 8.2 8.2 8.0 Bottom 10.0 9.0 9.1 7.6 7.0 6.o 6.0 4.5 5.1 2.4 8.1 6.4 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 30 o.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 45 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Bottom 0.0 1.9 0.9 2.6 2.2 4.0 5.0 4.4 5.3 1.8 0.0 Methyl Orange Alkalinity, ppm CaCO3 Surface 124 124 112 112 120 112 116 112 116 104 100 30 124 116 128 116 116 116 114 114 118 105 100 45 124 114 128 116 118 112 114 114 118 105 100 Bottom 120 111 96 114 112 116 110 108 114 104 100 Phenolphthalein Alkalinity, ppm CaCO3 Surface 5.0 6.o 4.0 5.0 4.o 5.0 5.0 2.5 5.0 2.0 2.0 30 6.o 5s.o0 4.0 3.0 3.0 4.0 4.0 2.5 5.0 2.5 2.0 45 4.0 4.o 0.0 3.0 3.0 3.0 3.0 2.0 3.0 2.0 2.0 Bottom 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 pH Surface 7.8 8.o 8.1 8.2 8.3 8.2 8.3 8.3 8.5 8.4 8.4 30 7.9 8.1 8.2 8.2 8.2 8.2 8.2 8.2 8.5 8.3 8.1 45 7.8 8.o 7.8 8.o 8.2 8.o 8.2 8.2 8.2 8.2 8.1 Bottom 7.8 7.8 7.7 7.6 7.6 7.6 7.3 7.3 7.3 8.1 8.o Secchi Disc, feet 27 43 47 22 35 27 25 155

1950 STATION 2 (42' 07.2', 81~ 53.9') Depth 1950 in Feet 5/26 6/7 6/15 6/25 7/5 7/14 7/18 7/26 8/8 8/24 9/1 10/1 Water Temperature, ~C Surface 11.9 16.3 17.2 21.2 20.1 21.4 21.6 20.8 21.9 21.9 22.4 19.4 30 8.6 12.2 12.6 17.2 19.7 20.7 21.0 20.5 21.5 21.6 22.4 18.0 45 5.6 6.6 8.5 15.0 14.7 20.6 20.7 20.4 21.3 21.5 22.4 17.8 Bottom 5.4 6.5 6.6 10.3 10.4 11.3 10.2 10.3 10.0 12.4 12.7 17.5 Mean 8.1 10.9 12.5 16.6 17.4 19.6 19.2 19.2 19.1 21.1 21.6 18.2 Mean of Mean of pim13.9 15.4 18.3 19.8 20.8 21.2 20.5 21.6 21.6 22.4 Epilimnion Dissolved Oxygen, ppm Surface 12.7 11.2 10.2 10.0 8.2 8.4 8.4 8.1 8.2 8.3 7.6 30 11.2 10.6 10.0 7.4 8.6 8.5 8.1 8.6 8.o 7.4 45 11.8 10.1 6.1 9.1 8.0 7.7 8.7 7.8 7.1 Bottom 12.0 11.8 10.1 9.4 6.9 7.6 7.5 6.1 3.8 3.8 7.1 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 30 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 45 0.9 1.3 1.8 0.4 0.0 0.9 0.0 0.0 0.9 Bottom 0.9 1.3 0.9 4.4 4.4 1.8 3.5 6.6 6.2 0.9 Methyl Orange Alkalinity, ppm CaC03 Surface 112 110 102 117 110 104 111 101 105 103 101 30 105 97 112 108 103 110 102 103 102 100 45 120 100 118 110 109 108 102 103 104 102 Bottom 115 107 100 116 98 107 110 103 105 106 102 Phenolphthalein Alkalinity, ppm CaCO3 Surface 3.0 1.0 2.0 2.0 1.0 3.0 2.5 3.0 2.5 2.0 30 1.5 2.0 1.0 1.0 3.0 2.5 3.0 2.5 1.0 45 o.o o.o 0.0 0.0 2.0 0.0 2.0 2.5 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 pH Surface 8.1 8.1 8.2 8.2 8.o 8.2 8.4 8.4 8.4 8.1 30 8.2 8.2 8.2 8.o 8.2 8.2 8.4 8.4 8.4 8.0 45 8.1 7.6 8.o 7.9 8.0 8.o 7.9 8.2 8.4 7.9 Bottom 7.9 8.0 7.6 7.6 7.8 7.7 7.4 7.3 7.5 7.2 7.8 Secchi Disc, feet 27 19 17 23 156

1951 STATION 2 (42' 07.2', 81' 53.9') Depth 1951 in Feet 5/23 5/30 6/12 6/21 6/28 7/2 7/12 7/18 7/23 8/2 8/8 8/24 8/28 9/2 Water Temperature, ~C Surface 9.1 13.0 15.8 18.5 19.1 19.3 19.9 21.9 21.6 22.3 21.3 21.3 21.8 21.3 30 9.0 11.3 17.1 17.7 18.8 18.9 20.0 21.2 22.1 21.2 21.3 21.5 21.3 45 8.6 8.o 12.4 17.1 8.7 14.7 14.9 16.0 21.2 21.2 21.3 21.4 21.3 Bottom 6.6 7.9 9.2 10.2 8.5 10.4 9.5 11.0 12.7 10.2 10.5 10.8 11.3 Mean 8.6 10.4 14.7 15.9 15.5 16.9 18.1 18.7 20.6 19.8 18.8 20.6 20.6 Mean of Mean of pii17.1 18.o 19.0 19.3 20.8 21.4 22.1 21.3 21.3 21.6 21.3 Epilimnion Dissolved Oxygen, ppm Surface 10.2 11.9 10.9 10.7 10.8 9.8 9.1 9.2 9.0 8.1 8.6 8.9 30 11.4 11.6 11.2 10.6 10.2 9.7 9.6 9.5 9.1 8.9 8.8 9.2 45 12.3 12.4 10.5 10.9 9.2 9.3 9.7 9.o 8.8 8.7 7.8 9.1 Bottom 11.1 11.3 10.6 10.5 9.2 9.2 9.0 8.7 8.3 7.4 5.6 4.7 Free Carbon Dioxide, ppm Surface 7.1 6.2 5.4 2.2 3.2 6.2 3.5 0.9 2.6 0.0 0.0 0.0 0.0 30 5.3 5.4 1.8 1.8 5.3 3.5 2.2 3.5 0.0 0.0 0.0 0.0 45 5.4 2.6 3.1 5.3 6.1 3.5 3-5 0.0 0.0 0.0 Bottom 5.4 4.4 3.6 7.1 5.3 4.4 4.4 3.1 4.8 1.8 3.1 Methyl Orange Alkalinity, ppm CaC03 Surface 100 120 126 107 108 101 104 104 106 104 104 104 102 30 120 120 107 107 103 104 104 102 103 105 105 105 45 122 109 110 105 105 106 108 102 105 105 Bottom 108 log log 104 105 108 109 105 104 107 108 Phenolphthalein Alkalinity, ppm CaC03 Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 4.0 3.0 5.0 3.5 30 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.0 2.0 2.5 3.0 45 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 2.0 1.5 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 pH Surface 7.8 7.8 7.8 7.7 7.9 7.6 8.o 8.2 8.3 8.0 8.0 8.0 8.3 30 7.8 7.9 7.8 7.9 7.7 7.9 8.1 8.3 8.o 7.9 8.4 45 8.o 7.7 7.6 7.7 7.7 8.0 7.9 8.0 8.4 Bottom 7.8 8.0 7.6 7.5 7.8 7.7 7.5 7.7 7.5 7.6 7.5 7.9 Secchi Disc, feet 13 11 40 23 29 22 26 157

1952 STATION 2 (42' 07.2', 81~ 53.9') Depth 1952 in Feet 6/4 6/12 6/17 6/27 7/5 7/14 7/29 8/8 8/19 8/30 9/5 Water Temperature, ~C Surface 13.7 14.9 18.5 18.7 21.9 23.1 25.2 23.7 L4.3 23.1 22.0 30 12.4 13.4 14.2 18.4 20.0 22.1 24.4 23.2 23.5 22.5 21.8 45 8.8 11.4 9.4 14.5 19.7 21.3 24.1 23.0 23.4 21.9 21.6 Bottom 8.7 9.7 9.1 9.8 11.2 11.4 11.2 11. 9 11.4 11.5 11.2 Mean 11.3 13.0 13.4 16.4 18.6 21.2 21.7 21.3 19.4 19.3 Mean of Mepan of,_16.5 19.6 20.3 22.4 24.3 23.3 23.6 22.6 21.8 Epilimnion Dissolved Oxygen, ppm Surface 10.5 9.8 8.8 8.3 9.1 8.6 6.6 8.8 9.0 9.7 30 10.7 10.0 6.4 9.1 9.1 8.5 6.7 8.o 9.2 8.9 9.8 45 10.6 10.0 5.7 8.9 8.7 8.7 7.3 8.3 8.9 8.9 9.6 Bottom 11.0 10.4 5.8 8.6 8.1. 8.3 6.9 5.9 8.3 4.7 9.5 Free Carbon Dioxide, ppm Surface 1.3 2.0 0.0 0.0 2.3 0.0 0.0 0.0 0.0 0.3 30 2.0 1.3 0.7 3-3 0.0 2.3 8.6 3.0 0.0 0.0 1.0 45 2.5 1.7 1.7 0.7 0.0 0.0 0.0 0.0 0.0 0.0 1.7 Bottom 1.5 2.3 1.7 1.7 4.0 2.0 1.7 3-3 2.3 0.0 4.0 Methyl Orange Alkalinity, ppm CaC03 Surface 114 o106 105 108 97 107 101 97 102 105 81 30 log 112 112 109 102 log 100 97 104 104 95 45 115' 114 115 111 104 107 100 104 84 103 94 Bottom 113 112 108 114 110 107 96 107 113 107 89 Phenolphthalein Alkalinity, ppm CaCO3 Surface 0.0 0.0 0.0 0.0 6.0 0.0 2.0 3-5 6.5 6.0 0.0 30 0.0 0.0 0.0 0.0 3.5 0.0 0.0 0.0 5.5 11.5 0.0 45 0.0 0.0 0.0 0.0 1.5 4.0 2.0 4.0 10.0 6.5 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 12.0 0.0 pH Surface 8.o 8.o 7.4 8.4 8.2 8.o 8.2 8.2 8.3 8.4 7.9 30 8.2 7.9 7.8 8.0 8.1 7.9 7.5 8.4 8.4 8.2 45 7.8 7.9 8.0 7.9 7.9 8.0 7.9 8.4 8.0 8.2 8.4 Bottom 8.o 7.9 7.4 7.9 7.6 7.9 8.0 7.4 8.0 7.8 8.3 Secchi Disc, feet 15 28 48 28 42 28 28 28 25 19 158

1947 and 1948 STATION 3 (42~01.2', 81'52.8') STATION 4 (41'56.4', 81'52.8') STATION 5 (41~51.6', 81'52.8') Station Depth 3 4 5 1 4 3 4 15 3 4 4 ein 1947 1948 8/.3 8/1 3 8/13 8 9/27 9/27 9/27 4/23 4/23 4/23 6/4 6/4 6/4 7/8 7/8 7/8 8/1 Water Temperature, ~C Surface 25.0 25.9 26.7 16.8 18.4 18.6 4.2 4.5 4.6 16.0 16.6 16.4 20.6 20.2 20.0 21.5 30 23.4 23.2 23.7 16.4 18.4 18.4 4.2 4.3 4.3 12.3 19.0 19.3 45 21.8 20.7 21.5 16.2 17.7 18.0 10.6 12.1 16.921.1 60 11.0 10.5 11.3 16.0 11.7 11.o 10.5 10.2 16.4 17.4 11.2 Bottom 10.7 10.5 10.7 14.7 11.0 11.0 4.2 4.2 4.2 10.5 10.7 10.2 9.6 11.3 11.6 10.9 Mean 20.0 20.1 20.8 16.4 17.0 16.8 4.2 4.3 4.3 11.7 12.4 12.1 16.4 17.4 17.8 18.6 Mean of eapillanon 23.7 23.5 24.0 18.1 18.4 19.5 18.6 19.1 21.3 Epilimnion Dissolved Oxygen, ppm Surface 11.6 8.3 8.9 9.2 8.5 30 9.0 11.6 9.0 45 8.1 60 6.7 Bottom 7.6 11.6 3.4 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 30 0.0 0.0 0.0 0.0 45 0.0 0.0 0.0 0.0 0.0 60 0.0 0.0 1.3 0.9 1.8 Methyl Orange Alkalinity, ppm CaCO3 Surface 100 105 102 96 99 102 30 104 99 100 104 45 103 104 100 99 104 60 100 105 108 108 106 108 Bottom 104 104 104 Phenolphthalein Alkalinity, ppm CaCO3 Surface 4.0 5.0 4.0 5.0 4.0 5.0 30 1.6 4.4 7.2 5.0 45 3.0 3.0 6.8 6.0 4.0 60 4.0 1.0 0.0 0.0 0.0 Bottom 3.0 pHSurface 8.0 8.1 8.1 8.1 8.4 8.4 8.4 30 8.1 8.1 8.1 8.4 8.4 8.4 45 8.1 8.1 8.2 8.4 8.4 60 8.0 8.1 8.1 7.9 7.4 7.6 7.2 Bottom 7.4 159

1949 and 1950 STATION 3 (42~01.2', 81'52.8') STATION 4 (41'56.4', 81'52.8') STATION 5 (41~51.6', 81'52.8' ) Station Depth 19 5 | 3 4 5 3 4 4 in Fee 1949 1950 8/4 8/4 8/4 8/23 8/23 8/23 6/8 6/8 6/8 7/26 7/26 7/26 Water Temperature, ~C Surface 24.8 24.3 24.0 23.6 23.8 23.7 17.1 16.3 16.0 20.7 20.7 21.0 30 23.8 23.8 23.8 22.9 23.4 23.1 12.5 12.2 12'.7 45 23.5 23.5 22.4 22.6 23.1 23.0 9.2 9.1 6.4 20.2 20.3 20.3 60 11.5 11.0 11.1 13.2 12.5 12.1 6.4 6.2 6.3 8.8 14.5 9.1 Bottom 11.2 11.0 10.8 12.3 11.8 11.6 6.3 6.2 6.3 8.7 8.6 9.0 Mean 20.1 21.0 19.6 21.3 21.3 20.1 10.9 10.6 10.7 18.0 18.1 17.1 Mean of Mean of 23.9 23.8 23.7 23.1 23.4 23.1 13.8 20.4 13.4 20.5 13.6 20.6 Epilimnion Dissolved Oxygen, ppm Surface 8.7 8.8 8.7 11.5 9.4 10.5 8.4 9.4 9.7 30 8.8 8.9 8.8 11.6 11.1 11.3 9.4 9.4 9.5 45 8.8 8.7 8.9 11.7 11.3 10.4 9.6 9.6 9.4 60 6.4 6.2 6.9 10.8 11.1 10.1 8.3 8.2 8.3 Bottom 6.2 6.4 6.7 11.4 11.6 10.1 7.9 8.3 7.9 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 30 0.0 0.0 0.0 0.0 o.o 0.0 o.o 0.0 0.0 0.0 0.0 0.0 45 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.0 0.9 0.0 0.0 0.0 60 5.0 2.0 3.0 1.8 2.6 2.2 1.3 1.3 2.2 1.8 1.8 2.6 Bottom 5.5 4.0 4.0 4.5 4.0 3.5 2.2 1.8 3.5 3.5 2.6 2.6 Methyl Orange Alkalinity, ppm CaCO3 Surface 116 116 114 116 116 120 100 105 109 109 110 110 30 114 114 114 118 116 116 97 110 109 110 108 45 114 116 114 116 116 118 97 105 108 109 110 108 60 110 112 11 0 114 114 114 96 107 97 110 108 108 Bottom 108 110 110 116 116 112 102 100 104 110 108 106 Phenolphthalein Alkalinity, ppm CaCO3 Surface 5.0 5.0 5.0 5.0 5.0 5.0 2.0 2.0 4.0 6.0 6.0 6.0 30 2.0 5.0 4.0 5.0 4.0 4.0 4.0 5.0 3.0 4.0 6.0 6.0 45 2.0 4.0 4.0 4.0 4.0 3.0 0.0 5.0 0.0 4.0 6.0 6.0 60 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Surface 8.2 8.2 8.2 8.5 8.5 8.5 7.9 8.1 8.1 8.2 8.2 8.2 30 8.2 8.2 8.2 8.5 8.5 8.5 8.0 8.0 8.0 8.2 8.2 8.2 45 8.2 8.2 8.1 8.4 8.5 8.2 7.9 7.6 7.8 8.0 8.2 8.2 60 7.4 7.5 7.5 7.7 7.5 7.8 7.7 7.6 7.6 7.7 7.4 7.5 Bottom 7.3 7.4 7.3 7.4 7.3 7.5 7.7 7.6 7.6 7.4 7.4 7.4 Secchi Disc, feet 26 27 25 26' 22 26 23 160

1951 STATION 3 (42~ 01.2', 81~ 52.8' ) STATION 4 (41~56.4', 81~52.8') STATION 5 (41i51.6', 81~52.8') Station Depth 4 5 3 4 5 3 4 5 3 4 1951 Feet 5/30 5/30 5/30 6/12 6/ 6/ 16/12 6/28 6/28 6/28 7/18 7/18 7/18 i 8/28 8/28 8/28 Water Temperature, ~C Surface 11.6 11.7 11.8 15.5 15.8 20.5 20.7 20.2 23.0 23.6 24.2 22.3 24.6 24.i 30 9.7 9.9 10.9 13.7 14.3 17.0 17.5 18.0 21.3 19.4 18.6 21.5 22.1 21.6 45 9.3 9.8 10.8 10.1 10.4 16.5 12.1 12.6 18.5 16.6 16.3 21.4 21.6 21.4 60 6.3 6.4 6.9 6.8 6.8 7.7 7.2 7.2 7.9 8.1 8.0 10.2 20.8 9.6 Bottom 6.3 6.4 6.9 6.8 6.7 7.7 7.1 7.2 7.8 8.0 7.8 10.2 10.2 9.4 Mean 9.3 9.1 9.7 11.2 11.5 14.8 13.7 12.4 16.7 16.0 16.2 19.7 20.4 19.2 Dissolved Oxygen, ppm Surface 11.4 11.6 10.7 11.7 11.5 11.0 10.0 9.8 10.0 9.2 9.3 9.1 9.0 9.2 9.1 30 11.3 12.2 10.6 12.2 10.3 10.8 10.5 10.1 9.8 9.5 9.7 9.3 9.0 9.3 8.9 45 12.3 12.6 10.6 12. 12.3 11.9 10.0 10.5 9.9 9.6 9.7 9.3 9.0 9.0 60 10.9 12.1 9.6 11.4 11.4 11.9 10.2 10.4 9.5 8.9 8.9 3.2 Bottom 10.9 11.6 8.0 10.9 11.0 10.1 10.0 10.3 10.0 8.5 8.2 9.6 2.1 4.9 5.0 Free Carbon Dioxide, ppm Surface 10.6 10.6 6.2 6.2 4.4 5.3 5.3 3.5 35.5 0.9 3.1 3.1 0.0 0.0 30 4.4 4.4 5.3 3.5 4.4 2.2 1.3 4.8 0.0 0.0 0.0 45 4.4 5.3 3.5 5.3 3.0 3.1 2.2 0.0 0.0 60 4.4 3.5 5 5. 5.3 4.4 5.7 2.6 2.6 Bottom 7.0 5.3 7.1 3.5 7.0 5.3 4.4 5.3 4.4 4.4 6.6 0.9 Methyl Orange Alkalinity, ppm CaC03 Surface 118 116 120 108 110 108 106 110 110 104 104 102 104 104 30 104 106 120 106 107 106 104 106 108 104 106 45 108 106 108 110 106 104 103 105 102 60 112 112 109 110 106 104 105 103 Bottom'110 110 112 112 109 109 108 108 105 105 104 106 Phenolphthalein Alkalinity, ppm CaCO3 Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.0 1.0 30 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 5.0 1.0 3.5 45 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.0 2.0 60 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 pH Surface 7.8 7.8 7.8 8.0 7.9 6.8 7.9 8.2 8.2 8.0 8.0 7.9 8.4 8.0 350 7.5 7.9 7.7 8.0 7.9 7.8 8.0 7.7 8.5 8.2 8.4 45 7.7 7.6 7.9 7.6 7.5 7.7 7.8 8.3 8.3 60 7.7 7.7 7.9 7.6 7.3 7.4 7.4 Bottom 7.7 7.6 7.6 7.6 7.6 7.6 7.3 7.5 7.3 7.4 7.5 7.5 Secchi Disc, feet 17 18 18 26 30 30 30 45 37 26 31 32 161

1950 and 1951 STATION 6 (41~ 43.8', 81' 55.8') STATION 7 (41' 34.8', 82~ 04.2') STATION 8 (41' 27.6', 82' 22.8') STATION 9 (41' 30.0', 82~ 40.8') STATION 14 (41' 53.4', 82' 24.6') STATION 15 (41~ 58.2', 82' 15.0') STATION 16 (42' 01.8', 82' 04.2') Depth Station in 14 15 16 14 15 16 6 7 8 9 14 15 16 Feet 1950 1951 6/25 6/25 6/25 7/30 7/30 7/30 17/26 7/26 7/26 7/26 7 7/2 7/23 7/23 Maximum 45 58 65 38 63 69 66 52 42 28 50 65 65 Water Temperature, ~C Surface 22.4 21.8 21.8 22.4 22.4 22.4 21.2 20.5 24.7 26.3 24.1 22.4 22.2 30 8.7 18.2 18.5 17.7 20.8 20.9 20.5 19.5 21.3 9.6 20.8 21.2 45 8.5 8.5 16.9 19.7 20.2 19.4 19.1 9.4 18.4 15.2 60 8.8 12.5 8.2 9.1 9.3 9.2 Bottom 8.5 8.2 8.7 14.0 8.4 8.1 9.1 12.2 18.6 20.9 9.3 9.2 9.1 Dissolved Oxygen, ppm Surface 9.7 9.3 8.3 8.3 8.4 9.5 9.2 8.2 11.3 9.0 9.2 9.1 30 6.7 9.7 9.8 7.5 8.6 8.7 9.4 8.1 7.9 7.9 9.3 9.1 45 6.3 9.0 9.5 8.1 8.6 9.2 7.8 8.4 8.4 60 8.5 6.1 8.6 8.2 7.8 8.0 Bottom 6.3 9.1 7.5 6.9 4.7 7.6 7.7 Free Carbon Dioxide, ppm Surface 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.3 2.7 1.8 30 7.9 0.0 0.0 2.6 0.0 0.0 0.0 0.9 3.6 1'.4 2.7 45 13.0 8.8 0.0 0.0 0.0 1.3 0.9 4.5 3.2 3.6 60 16.7 4.4 1.8 1.8 5.4 4.5 Bottom 13.0 16.7 2.6 2.6 2.2 1.8 0.9 Methyl Orange Alkalinity, ppm CaCO3 Surface 113 116 112 105 106 104 108 108 108 106 102 104 106 30 115 115 119 107 106 106 109 108 105 104 108 45 125 113 116 105 -105 110 111 108 106 106 60 118 107 104 114 106 112 Bottom 125 132 107 100 111 108 108 Phenolphthalein Alkalinity, ppm CaCO3 Surface 0.0 2.0 2.0 2.5 2.5 2.5 2.5 2.0 3.0 3.0 0.0 0.0 0.0 30 0.0 1.0 0.0 0.0 2.0 2.0 1.5 0.0 0.0 0.0 0.0 45 0.0 0.0 0.0 2.0 2.0 0.0 0.0 0.0 0.0 0.0 60 0.0 0.0 2.0 0.0 0.0 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 pH Surface 8.0 8.2 8.2 8.3 8.4 8.5 8.2 8.2 8.2 8.5 8.3 8.1 8.3 30 7.9 8.2 8.2 7.5 8.2 8.2 8.2 8.2 7.6 7.9 8.2 8.2 45 7.4 7.7 8.2 8.2 8.2 8.o 7.8 7.8 8.2 7.6 60 7.4 7.3 7.5 7.5 7.4 7.6 Bottom 7.4 7.5 7.5 7.4 7.4 7.6 7.8 Secchi Disc, feet 30 7 10 27 30 162

1950 and 1951 STATION 18 (42~ 12.6', 81~ 32.4') STATION 20 (42~ 16.8', 81~ 10.8') STATION 22 (42~ 27.6', 80o 49.2' ) STATION 23 (42~ 28.8', 80O 31.8') Station Depth 18 20 22 2 18 20 22 2 18 20 22 2 18 20 22 2 in in 1950 1951 Feet 7/5 7/5 7/ 7/6 I 8/8 8/8 8/8 8/11 7/2 7/2 7/2 7/5 8/8 8/8 8/8 8/9 Maximum 73 65 58 48 71 67 60 52 75 70'65 55 73 73 61 50 Water Temperature, ~C Surface 19.7 20.2 18.6 18.0 22.1 22.5 22.4 21.1 18.8 19.0 19.6 20.8 21.9 21.8 21.2 21.9 30 16.4 16.7 15.4 13.6 20.9 21.2 20.8 18.0 18.5 18.5 19.2 19.5 21.5 21.5 20.5 20.3 45 7.8 16.0 7.3 8.5 20.5 21.0 20.4 15.2 7.7 8.3 8.6 5.9 21.4 21.4 15.8 16.1 60 7.6 8.1 10.7 20.8 13.6 7.6 8.3 8.5 10.9 10.9 11.2 Bottom 7.4 8.0 7.2 8.3 10.3 14.2 13.6 14.7 7.6 8.3 8.5 5.8 10.8 10.8 11.2 14.7 Dissolved Oxygen, ppm Surface 8.2 9.1 8.2 10.0 8.7 9.7 8.4 9.8 9.6 9.5 9.3 8.3 8.8 9.0 9.0 30 8.4 8.6 8.4 9.5 8.3 7.2 9.9 g.0 9.7 9.6 9.5 9.5 8.6 8.8 g.0 45 8.7 g.0 8.0 8.2 6.5 9.7 8.8 10.7 9.8 9.5 12.1 8.9 8.8 8.0 60 8.1 9.0 7.3 4.8 8.3 9.5 9.6 9.5 6.2 6.6 7.9 Bottom 7.5 8.8 8.0 9.8 7.3 4.4 8.3 8.5 9.1 9.0 12.3 6.3 6.3 7.9 8.5 Free Carbon Dioxide, ppm Surface 0.0 0.0 O.G 0.0 0.0 0.0 0.0 0.0 3.5 3.5 3.5 3-5 8.0 0.9 2.6 0.0 30 0.0 0.0 0.9 0.0 0.0 0.0 0.0 0.0 5.3 4.4 4.4 5.3 0.0 0.0 1.3 0.0 45 0.0 2.6 1.3 0.0 o.0 0.0 0.9 5.3 4.4 4.4 7.0 13.2 0.0 3.5 60 2.6 0.0 1.8 5-3 6.2 5.3 6.2 3.1 4.0 Bottom 2.6 1.8 3-5 1.8 1.8 1.3 5.3 7.0 5.3 3.5 4.0 1.3 Methyl Orange Alkalinity, ppm CaC03 Surface 100 lO 106 104 105 98 99 104 104 101 104 104 102 104 104 102 106 30 100 110 ll0 108 98 100 103 105 101 101 104 103 105 103 105 45 105 100 107 105 101 101 101 103 100 102 105 104 105 105 60 130 0 108 99 100 100 102 103 108 106 106 Bottom 120 78 103 106 104 105 100 104 102 106 o107 6 106 106 8 Phenolphthalein Alkalinity, ppm CaCO3 Surface 2.0 2.0 2.5 2.5 2.5 2.0 2.5 2.0 0.0 0.0 0.0 0.0 3.0 0.0 0.0 3.0 30 1.o 2.0 0.0 2.0 1.5 1. 0 3 1.0 0o.o o.o o.0 2.0 3.0 0.o 3.0 45 0.0 1.0 0.0 0.0 1.5 2.0 2.5 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.0 6o0.0 0.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Bottom 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ph Surface 8.1 8.2 8.0 8.2 8.4 8.4 8.4 8.4 7.9 7.9 7.9 7.9 7.9 7.9 8.2 30 8.0 8.1 8.0 8.0 8.3 8.2 8.4 8.2 8.0 7.8 7.9 8.0 8.2 7.8 8.2 45 7.6 8.0 7.8 7.7 8.2 8.2 8.3 7.8 7.8 7.6 7.7 7.8 7.8 8.0 7.5 60 7.5 7.6 7.3 8.2 7.6 7.6 7.5 7.6 7.5 7.7 7.4 Bottom 7.4 7.4 7.8 7.6 7 74 7.6 737 74 7.4 7.6 7.7 7.4 8.1 Secchi Disc, feet 23 23 21 19 163

1950 and 1951 STATION 24 (42'27.6', 79'54.0') STATION 25 (42~31.8', 80~02.4') Depth Station 24 Depth Station 25 Feet 7/6/50 8/10/50 7/3/51 8/9/51 in 7/7/50 8/10/50 Maximum 197 180 197 190 112 127 Water Temperature,'C Surface 17.9 20.1 20.2 21.1 Surface 17.8 20.8 30 13.8 20.1 17.4 20.9 50 13,0 18, 4. 60 7.8 14.5 5.2 10.2 45 10.6 15.5 90 5.7 6.1 4.2 6.9 60 9.7 11.3 120 4.3 4.0 4.0 5.5 75 8.2 6.5 150 4.0 4.0 4.0 4.6 90 4.2 4.4 Bottom 3.9 4.0 4.0 4.4 Bottom 4.0 4.1 Dissolved Oxygen, ppm Surface 8.8 9.2 8.9 Surface 8.1 9.0 30 9.4 9.5 9.0 30 8.7 9.2 60 9.2 12.3 9.0 45 8.7 9.0 90 8.2 12.6 9.9 60 8.3 9.6 120 9.1 12.8 11.4 75 8.0 9.3 150 9.1 8.2 12.0 11.3 90 9.0 9.5 Bottom 8.2 11.2 10.0 Bottom 8.0 8.7 Free Carbon Dioxide, ppm Surface 0.0 0.0 5.3 0.0 Surface 0.0 0.0 30 0.0 7.0 0.0 30 1.3 0.0 60 1.8 7.0 2.6 45 1.3 0.4 90 1.3 5.3 1.7 60 1.3 1.8 120 2.6 6.1 1.3 75 2.2 1.8 150 2.6 1.8 5.3 0.9 90 3.1 1.8 Bottom 2.2 5.53 1.3 Bottom 2.6 2.6 Methyl Orange Alkalinity, ppm CaC03 Surface 110 104 104 106 Surface 112 102 30 108 104 106 30 110 100 60 106 104 106 45 119 102 90 104 103 106 60 110 101 120 110 103 106 75 113 105 150 111 105 105 106 5 90 112 105 Bottom 106 109 106 Bottom 114 110 Phenolphthalein Alkalinity, ppm CaC03 Surface 2.0 1.5 0.0 4.0 Surface 3.0 2.5 30 1.0 0.0 3.0 30 0.0 2.0 60 0.0 0.0 0.0 45 0.0 0.0 90 0.0 0.0 0.0 60 0.0 0.0 120 0.0 0.0 0.0 75 0.0 0.0 150 0.0 0.0 0.0 0.0 90 0.0 0.0 Bottom 0.0 0.0 0.0 Bottom 0.0 0.0 pH Surface 8.2 8.2, 8.0 8.2 Surface 8.2 8.4 30 8.1 7.8 8.2 30 7.9 8.3 60 7.7 7.6 7.9 45 7.9 7.9 90 7.6 7.7 8.1 60 7.8 7.6 120 7.8 7.6 8.0 75 7.8 7.5 150 7.8 7.5 7.5 7.9 90 7.7 7.5 Bottom 7.6 7.5 7.9 Bottom 7.7 7.4 164

3 l015 03696 5568