The effect of large pools (i.e. lakes) on streams.

Abstract

The effect of lakes on rivers is a poorly studied phenomena. As a river runs through the lake, it is effected by the ground water inputs in the lake and the residence time of the water. The assumption was made that nutrient levels would decrease, while discharge and conductivity increased. Water samples were collected and discharge was taken at each of the inlets and outlets. The samples were analyzed for nitrates, total nitrogen, SRPs, conductivity and Gilvin. The streams that encountered natural lakes howed an increase in discharge, and conductivity; while the stream that passed through an impoundment experienced a decrease in these two factors. In all three lakes sampled, nitrates, SRPs, and Gilvin underwent a decrease from inflow to outflow. The largest natural lake experienced an increase in total nitrogen, even though both the other lakes caused the load of total nitrogen to decrease. From this data, natural lakes can be assumed to reduce nutrient loads while increasing flow. It can also be assumed that impoundments decrease both nutrient loads and flow.