Seal of Dane County County of Dane
Dane County Land & Water Resources Department

Erosion and Stormwater for Agricultural Development

Boater inspecting and removing aquatic plants from their boat.


The way in which a farm is managed can either positively or negatively impact the health of a watershed.  The application of pesticides, fertilizers and manure may be needed to increase crop yields, but these products can easily leave the field as runoff and contaminate natural water bodies.

An excess of nutrients in a water body can encourage aquatic plant growth. When these aquatic plants die, the water oxygen levels can drop low enough to kill other organisms, such as fish. Farms are also subject to upstream contamination affecting their fields. For example, urban areas upstream from agricultural land, if left untreated, can deposit pollutants such as oil, dirt, and lawn fertilizers. Those chemicals disrupt the fertility of soil and contaminate crops.

There are many practices farmers can implement to ensure that stormwater is treated and erosion is controlled before it becomes a problem. Some of the more common practices include nutrient management, contour farming practices, cover crops, field buffers, and conservation tillage. Staff can work with farmers to help implement these practices on farmed lands. Staff can also work with farmers on development projects and land disturbance that are not directly related to the growing of crops. Before developing any part of a farmstead, please work with staff to determine if a stormwater management permit is necessary.

Stormwater Management Permits

A stormwater management permit is necessary when a cumulative 20,000 square feet of impervious surface is added to a farmstead. Only areas constructed after 2001 are counted, but any addition no matter how small counts toward this trigger. Impervious surfaces can be anything that prevents the infiltration of stormwater into the ground including graveled areas and permanent water pools such as manure storage facilities. 

If you are implementing a farm improvement project or operate a livestock facility a permit may be required. Use the questions on our Do I Need a Permit webpage to find out if you need a permit from our office.

Please use this checklist (PDF) before starting agricultural ditching, repairing tile, or breaking out new land.

Your project might also need to be reviewed by the Dane County Farm Services AgencyWisconsin Department of Natural ResourcesUS Army Corps of Engineers or other agencies. In some cases you may need to contact your local Drainage District. Please confirm permit requirements prior to beginning your projects.