Watershed Management Planning for the River Raisin: Perspectives on changing land use, dams, water quality and best management practices

Abstract

Current watershed management practices demand adaptive, cost effective strategies based upon a comprehensive understanding of the scientific and political issues pertinent to a specific watershed. The formation of a watershed management plan presents the stakeholders with an opportunity to develop this comprehensive understanding of their local environment though cooperative exchange of knowledge and research. To further stakeholder understanding of the watershed the authors selected three research topics pertinent to the River Raisin Watershed Plan and generated a cohesive final product which would permit an evaluation of the individual subwatersheds, educate stakeholders, and facilitating the decision-making process.

Despite being one of the most studied river systems in Michigan, the River Raisin continues to offer challenging ecological, cultural, and political issues for study. Upon initial evaluation three major issues attracted immediate notice: the lack of historical perspective for the watershed planning process, the dramatic effect of the local agricultural economy on water quality, and the long term, cumulative impacts of dams upon the river ecosystem.

The lack of historical perspective for formulating current and future management goals required a detailed review of pre-settlement land cover types to develop a map for each subwatershed. A comparison was then generated between historical and present day cover types to evaluate the changes. Finally, a brief study of the settlement in and around the watershed offered insights into the culture that shaped the modern land uses.

Agricultural practices have impacted the River Raisin since the time of early settlement, but the mechanized draining of Michigan’s extensive wetlands and the establishment of large-scale agriculture have caused the watershed to suffer significant degradation. Modern monoculture of corn and soybeans result in significant additions of pesticides, fertilizers, and eroded topsoil to the River Raisin. To evaluate the current levels of degradation the authors undertook an evaluation of the water quality for each subwatershed. The pollutants of interest were Total Nitrogen, Total Phosphorus, Total Suspended Matter, and Conductivity. The results were used to develop Geographic Information Systems-based scorecards which summarize the water quality of the subwatersheds and provide the basis for a discussion on Best Management Practices for the agricultural interests within the watershed.

Dams have existed on the River Raisin almost since the establishment of the first towns at the mouth of the river; the subsequent construction of more permanent structures magnified their impacts on the ecosystem. These dams were rarely removed unless there was an immediate and clear danger to life and property. To develop a more proactive stance toward dam removal in the watershed, a review of the literature was undertaken to provide a measure of the impacts and costs of dams on the River Raisin. Utilizing the results of this research a qualitative analysis of existing dams was developed. It yielded a list of sites where dam removal would be a suitable method of restoring the local ecosystem.