Groundswell partnered with WGVU and the GVSU Annis Water Resources Institute to create a series of educational videos and lesson plans about nonpoint source pollution. This type of pollution is one of the biggest threats to healthy lakes, streams, and rivers.
After you watch the above video, you can read the Background Information and complete the activities and handouts in the Student Handouts section.
The U.S. Environmental Protection Agency (U.S. EPA) lists sediment as the most common pollutant in rivers, streams, lakes, and reservoirs. It also is listed as a major pollutant in the Lower Grand River Watershed Management Plan (LGRWMP), the document used by watershed managers to restore and protect our local water resources.
Sediment refers to the organic and inorganic materials that can be carried away by water, wind, or ice. These materials eventually can be deposited and accumulate on the bed or bottom of a body of water. While the term is often used to indicate mineral-based soil particles (e.g. clay, silt and sand), decomposing organic substances and inorganic material from organisms are also considered sediment. In aquatic environments, sediment can be dissolved, suspended (floating in the water column), or bedded (settled on the bottom of a body of water).
Erosion is the process by which sediments are transported by wind, water, ice, or gravity. Often people mistake erosion for weathering, the process through which rocks are gradually chipped away by abrasion, water, and ice. However, erosion is the active movement of these sediments from one place to another. Sediments are carried in rivers – the river’s load – and deposited elsewhere.
While natural erosion produces nearly 30 percent of the total sediment in the United States, accelerated erosion from human use of land accounts for the remaining 70 percent. The most concentrated sources of excess sediment come from construction activities. Other sources of sediment include cropland, urban landscapes, stream bank erosion, rill and gully erosion, and lakeshore erosion.
The erodibility of soils is influenced by the texture and particle size. Silt (0.004mm – 0.062mm) is most easily eroded. Clay (<0.004mm) is cohesive and tends to remain bound together as larger chunks; however, once detached the particles remain in suspension. Sand (0.062mm – 2mm) is relatively large and more difficult to move. Gravel (>2mm) is also more difficult to move. Loam is a combination of sand, silt, and clay.
The Communities for Clean Water videos and lesson plans were made possible through a grant from the U.S. Environmental Protection Agency through the Michigan Department of Environmental Quality. As part of this grant, the number of individuals utilizing these resources needs to be reported. Please help with this process. Click HERE to complete a brief questionnaire. Thank you- your time is appreciated!