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Shiawassee River Watershed

The Shiawassee supports more than 40 species of fish and 12 species of freshwater mussel, an indicat
Shiawassee Basin Preserve
© TNC Archives
Read the Shiawassee River Report
Learn more about the effect of no-till farming on corn crops.

Why the Conservancy Selected This Site
The Shiawassee River is one of the best examples of a warm-water river system in its eco-region. The watershed is about 742,400 acres. Its waters support over 40 species of fish, including darters, minnows, and channel catfish, and 12 species of freshwater mussel. The river also plays an integral role in the travels of migratory waterfowl and shorebirds. Some of the best examples of their kind left, the swamps and fens adjacent to the river's headwaters support several globally rare species, including the Indiana bat, eastern massasauga rattlesnake, Blanding's turtle, and insects such as the powesheik skipperling.

Threats
Threats to the Shiawassee River change as the river flows from its headwaters to the lower mainstem. In the headwaters, which are, located mostly in Livingston and Oakland County—two of the fastest growing counties in Michigan—ongoing development threatens to degrade the wetlands and alter the hydrology of the stream. Land use along the lower portion of the river is dominated by agriculture and the stream is challenged by non-point source pollution—runoff that carries fertilizers, pesticides, and sediment. When a farmer plows a field, the goal is to break up the soil and turn under the weeds, seeds and other plant material for a clean seed-bed, but utilizing traditional tillage techniques means over 20 tons of soil per acre can end up in the River. Intensive agricultural production and the cumulative impacts of changing land use, along with altered hydrology, and invasive species all put stress on the Shiawassee and could one day dramatically alter the landscape and ruin its original appeal.

Our Conservation Strategy
As with threats, conservation strategies differ between the headwaters and mainstem portions of the watershed. The Conservancy and many partners including local townships, county governments, and other land trusts, continue to pursue land acquisition and stewardship in the headwaters area. One example is the Shiawassee Basin Preserve, owned by Springfield Township and now totaling about 600 acres, in which the Conservancy has assisted with invasive species control and prescribed burning. Municipalities have also instituted regulations on development and have incorporated conservation of natural areas into their Master Plans. In the lower mainstem, the Conservancy is making great strides in implementing conservation tillage, or “no-till” farming in the local agriculture communities in Shiawassee and Genesee Counties. No-till farming reduces the number of times a tractor drags equipment through a field, thereby minimizing soil disturbance, reducing erosion by more than 90% while also improving water quality by runoff by up to 70%. In addition to working with farmers, reestablishment of floodplain forests and vegetated buffers along streams will also reduce erosion, impede runoff, preserve the stability of the stream channel and improve wildlife habitat. Current riparian buffer projects will restore over 17 acres of floodplain to native hardwood tree species, protecting roughly a mile of the river.

What the Conservancy Has Done/Is Doing
The Nature Conservancy has a project office is Owosso, Michigan. Since then, staff has enrolled more than 10,000 acres of farmland that drains into the Shiawassee River in our no-till programs, as well as 2,000 acres outside the Shiawassee. A grant has enabled the Conservancy to purchase special equipment now available for leasing to local farmers to encourage them to try no-till farming without incurring substantial financial risk.

Read the Shiawassee River Report.

Drainage tiles and agricultural ditches also threaten the natural water flow of the Shiawassee, and the Conservancy is working with county drain commissioners, local farmers, and state and federal agencies to promote the use of a new environmentally beneficial two-stage ditch design that reduces ditch-bank erosion and sedimentation.

Most drainage ditches are trapezoidal in shape, allowing for quick drainage for conveying large quantities of water, but often oversized for low flows and providing no floodplain for high flows. Such channels are inherently unstable and ultimately result in sediment filling in the channel and needing to be dredged periodically at a high cost to the landowner.

Vegetation in the second “stage” (flood-plain) of the ditch helps stabilize the channel, reducing erosion and helping to filter any incoming and excess water. By imitating the floodplain and main channel of a natural stream, the design will be more stable in the long-term, reducing the need for further dredging or other related maintenance costs.

To learn more about conservation farming, two-stage ditch design, the Shiawassee Program, and other Conservancy water projects, read our Fall Newsletter 2005. Read an article about Naturalized Agricultural Drains in the 2005 Second Quarter edition of Pipeline, the Michigan Association of County Drain Commissioners' magazine.