River Raisin Watershed Management Plan, Phase 1

Abstract

Abstract The River Raisin Watershed drains 2,780 square kilometers of southeastern Michigan and northern Ohio, terminating in Lake Erie. Currently, agriculture dominates the watershed (73 %)but exurban development is contributing to a changing landscape. As a result, the river and associated tributaries are heavily impacted and in need of a management plan that identifies threats to the watershed’s health and proposes appropriate responses. The River Raisin Watershed Council (RRWC) and The Nature Conservancy (TNC) of Michigan, both active in advocating for watershed protection, enlisted the project team’s help in developing this plan. The results of this analysis will guide TNC and the RRWC to develop strategies to effectively manage the natural resources of the watershed. The team investigated three areas of importance in developing watershed protection strategies: 1) water quality in the upper watershed, 2) identification of conservation targets in the upper watershed using a GIS model and habitat assessment, and 3) analysis of local ordinances throughout the watershed that address stormwater management, preservation of natural areas, and reduction of impervious surfaces using a scoring system developed by the Center for Watershed Protection. The main stem of the River Raisin above the village of Manchester has the best water quality and also has the largest amount of priority area for habitat conservation. The subwatersheds of Hazen and Evans creek exhibited the poorest water quality in the upper watershed. The South Branch of the River Raisin and parts of Evans Creek are also the areas of lowest conservation value based on available habitat. The cities of Tecumseh and Adrian, the major population centers in these subwatersheds, are the local governments that need the most revision of local ordinances to improve water quality and stormwater management. Based on our analysis we recommend specific locations that could serve as focal areas for conservation planning and model ordinances to improve water quality.