Lake St. Clair Assessment Introduction
The Clinton River Watershed encompasses most of Macomb and Oakland Counties, with small portions extending into Lapeer and St. Clair Counties. It drains approximately 760 square miles, an area which is populated by an estimated 1.5 million persons, before reaching Lake St. Clair. The majority of the land within the watershed is developed for industrial, urban and suburban uses. Although agriculture is still common along the North Branch of the Clinton River, farmland is diminishing rapidly due to urban expansion. Since urban expansion alters natural drainage, an increasing amount of water reaches Lake St. Clair via storm water systems.
The water flowing through Lake St. Clair is a precious natural resource that provides drinking water for millions, numerous recreational opportunities and is essential to the businesses and homeowners adjacent to the shoreline. Notwithstanding the importance of Lake St. Clair, many water quality problems exist. In 1985, the International Joint Commission designated the lower Clinton River basin as an Area of Concern, due to elevated fecal coliform bacteria, total dissolved solids levels, contaminated sediments, and a degraded benthic macroinvertebrate community. During the 1990's, the Macomb County Health Department frequently closed beaches on Lake St. Clair due to violations of total body contact standards for indicator bacteria. Early in 1997, Macomb County established the Blue Ribbon Commission on Lake St. Clair to develop an action plan addressing water quality issues. Monitoring water and sediment quality was the first of four key elements the Commission listed as necessary in solving the problems facing Lake St. Clair.
The water quality concerns in Lake St. Clair and the Clinton River Watershed include pathogens, toxic contaminants and eutrophication. Historically, the primary reason for water pollution control was the prevention of waterborne disease. Humans can acquire bacterial, viral or parasitic disease through direct contact or drinking contaminated water. Today, the discharge of sewage to the lake from many sources continues, along with the associated risk of human exposure to many pathogenic organisms.
Toxic contaminants include man-made organic chemicals and heavy metals that can be acutely poisonous in small amounts and injurious through chronic exposure in minute concentrations. Human exposure can result from direct contact with contaminated water or sediment, or indirectly through the food chain. The danger of toxic substances was first illustrated with the study of the persistence, bioaccumulation and effects of DDT in the environment. Currently, fish consumption advisories exist on Lake St. Clair to reduce human exposure to several toxic pollutants.
Urbanization increases the amount of nutrients and organic material entering the lake. This increased loading can quicken the aging process of a lake, known as eutrophication, through excessive plant growth and oxygen depletion. Eutrophication reduces the biodiversity in the lake, replacing the natural inhabitants with a smaller variety of less desirable species of plants and animals.
To view the Site Summary Data Key click here
To view the Watershed Sample Map click here
To view the Sample Site Map click here