This past year was exciting and eventful for the Chisago Soil & Water Conservation District (SWCD) and the Natural Resource Conservation Service (NRCS). Together, the two agencies worked to install 12 new rain gardens, 10 water and sediment control basins or grade stabilizations, 10 grassed waterways or diversions, 2 lined waterways or gully stabilizations, and a pervious asphalt installment on a parking lot. Together, these practices are reducing the amount of sediment and phosphorus reaching local lakes and rivers, including the St. Croix River, by 234 tons per year and 315 pounds per year, respectively.
Most of these projects were installed in the southern portion of the county, in the Chisago Lakes Chain of Lakes watershed or along the St. Croix River escarpment. The Chisago SWCD has grant money from the Clean Water, Land and Legacy amendment’s Clean Water Fund to install projects in these watersheds. In some cases, NRCS worked with landowners to enroll them in federal programs that may also provide partial funding on some projects. In other cases, the landowners themselves also contributed money from their own pocket to complete some of the projects. Another important funding partner in the Chisago Lakes Chain of Lakes watershed is the Chisago Lakes Lake Improvement District (LID). Their contributions help the Chisago SWCD meet the requirements of local match for Clean Water Fund grants. Without this match money, landowners would have to contribute their own match funding to receive the grant money.
The projects were installed in both urban and rural areas and addressed a range of issues, from gullies to sheet and rill erosion, to dirty runoff water. Water and sediment control basins and grade stabilization projects are often used on agricultural fields where runoff is causing soil erosion and large gullies. Some of the gullies that were stabilized in 2015 were on the shoreline of local lakes, making them a direct contributor of sediment and phosphorus to poor water quality in those lakes. To cut off the flow of water to the existing gully, a large berm is created to form a temporary storage area for runoff water. A pipe is installed inside of the storage area that allows the water to drain out at a slow pace so that it doesn’t cause continued erosion within the gully. The water is often drained away within a day after the rainfall.
Grassed waterways and diversions are a practice used commonly in agricultural fields to reduce erosion that is occurring where water concentrates and runs. The runoff often causes small but continuous gullies in the field that can cause problems for the farmer as well as carrying sediment and phosphorus into nearby waters. The area where the water flows is converted from crop to a permanent vegetation, such as grass or hay. Water is able to travel through the waterway without eroding the soil beneath it.
Rain gardens are used in the urban areas, where the goal is to help water infiltrate into the ground instead of running over impervious surfaces into the storm sewer system, which outlets directly into a lake. Rain gardens are strategically placed to intercept runoff water and allow it to pool in the garden temporarily. As much of the water that can soak into the ground is allowed to do so over 24-48 hours. In areas with clay soils that don’t accept much water, an underdrain may be installed in the garden to help release the water after it has been filtered through a sandy soil to remove as much sediment and phosphorus as possible.
Plans are already shaping up for the 2016 season, with many more projects expected to be installed. If you have an erosion problem, you may be eligible for grant funding. Contact the Chisago SWCD at 651-674-2333 for more information. For a virtual tour of some of these projects, visit www.chisagoswcd.org and click on the Interactive Map.