Pollutants and Sources

What Are the Main Pollutants Threatening the Watershed’s Uses?

Photo courtesy of the Grand Traverse Conservation District

Excessive sedimentation and nutrients are two of the main known pollutants that are affecting the Grand Traverse Bay Watershed. Nutrients are a high priority pollutant for both the Grand Traverse Bay and its tributaries, while sediment is a high priority mainly in rivers and streams feeding the bay.

The picture above shows a severe erosion site along the Boardman River. Streambank erosion from sites such as this are a primary source of sedimentation in surface waters throughout the Grand Traverse Bay watershed.

Maintaining the high water quality in the Grand Traverse Bay and its watershed will require minimizing the amount of nutrient and sediment pollution that enters the bay from adjacent properties and tributaries. Changes to hydrological flow, mainly due to stormwater inputs, are also a concern throughout the watershed. Along with affecting the hydrology in the watershed, stormwater may also carry excessive amounts of nutrients, sediments, and toxins into the bay and its tributaries. Note: Nutrients often attach to soil particles, thereby linking sedimentation to nutrient pollution.

Other pollutants threatening the water quality and designated uses throughout the Grand Traverse Bay Watershed include: thermal pollution, toxins, invasive species, pathogens, and loss of habitat.

Additional Concern: Invasive Species

Zebra Mussel Spiney Water Flea [Click here to view full size picture]

A growing nuisance…

Of great concern to the Grand Traverse Bay is the impact invasive species have, or will have, on its ecosystem. While not a primary concern throughout rivers and streams in the watershed yet, invasive species are already beginning to change the ecosystem and habitat dynamics in the bay.

A few of the invasive species found in the Grand Traverse Bay include the sea lamprey, zebra mussels, rusty crayfish, spiny water flea, and the fish-hook water flea.

A Comprehensive Watershed Management Table

In addition to the known pollutants in the watershed, there are a number of different sources and causes for each of those pollutants. These results are compiled in what we call a Comprehensive Watershed Management Table.

An additional comprehensive watershed management table was made for pollutants, sources, and causes specific to the Grand Traverse Bay. This is because certain pollutants have more of an impact on streams and lakes rather than on larger bodies of water like the Bay (i.e., thermal pollution and sediment), and other pollutants are more of a concern for the Grand Traverse Bay only (i.e., invasive species).

The listing of pollutants and their sources and causes were ascertained through scientific research reports, existing subwatershed management plans, DEQ water quality reports, field observations, Steering Committee members, and personal contact with watershed residents and scientific experts on the Grand Traverse Bay watershed.

Please click on the links below to see a PDF version of each of the Comprehensive Management Tables. Note: You must have the free Adobe Acrobat Reader software to view these files.

* Grand Traverse Bay Watershed Comprehensive Watershed Management Table

* Grand Traverse Bay ONLY Comprehensive Watershed Management Table

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