Water and Sediment Control Basins

Throughout my career as a Water Quality Specialist I have focused on ways to help mitigate cropland erosion through the use of engineered structural Best Management Practices (BMP’s). I have assisted in the construction of many structural BMP’s. These practices very popular with producers in Redwood County because of their effectiveness at eliminating erosion issues. Due to our land topography, farmable water and sediment control basins are by far the most common. They’re also the easiest sell to producers because they are farmable, meaning no land has to be taken out of production. Over the years I have noticed that structural BMP’s are more plentiful in farm fields that are conventionally farmed verses ag lands that employ soil health practices because they actually do a great job reducing the movement of water across the landscape.

Water and Sediment Control Basins

Water and sediment control basins are often placed in areas where large amounts of water are forced through a small area, causing a gully to form. This occurs often on lands with rolling topography and sharper elevation changes such as river basins. Redwood County has three: the Redwood, Cottonwood, and Minnesota River drainage basins, which is why they’re popular in my district.

Control basins function by backing water up behind an earthen berm and flooding the area where gully erosion is a concern during rain events. This backed up ponded water then acts as a settling pond because ponded water cannot pick up soil and move it. The ponded water is slowly removed through a metered tile system within 35 hours after the rain event so growing crops are not damaged. Without the berm, water would rush right through and take all the topsoil with it, creating a gully that can’t be farmed or crossed with farm equipment.

Non-Structural Erosion Practices

While structural BMP’s are very effective, they only serve the single purpose of stopping concentrated gully erosion and could potentially be quite expensive to construct. Which brings me back to soil health practices and its effects on erosion. Practicing things like reduced tillage systems (No-till, Strip-till), and cover crops can greatly reduce the need for high dollar structures. These practices keep soils covered all season long, increasing soil organic matter, and increasing water infiltration. For every 1 percent increase in soil organic matter the soil profile can hold an extra 16,000 gallons of water. Living roots all season long also increase the infiltration of water making soil more porous due to root systems that have died back and decomposed. Increasing the amount of water the soil is able to hold greatly reduces the effects of water-driven erosion.

Cover crops also help with taking power out of the rain drop because there is less bare soil for rain drops to hit. and detach soil particles that once detached are prone to movement. In areas where water can become concentrated and move swiftly, residue left from cover crops and cash crops slows down the velocity of water movement. This prevents the water from picking up soils particles and allows those particles that are moving to drop out and remain on the field where they’re needed.

Soil heath practices offer new options for producers that can reduce soil erosion, but that’s not all. There are many other effects not directly related to erosion that are beneficial to both the landowner and the environment. I understand that in field structural BMP’s will stop gully erosion from happening but sometimes practicing simple soil health practices are enough to stop erosion and eliminate the need from more expensive structures in the field. I do want to caution, just because you are utilizing soil health practices sometimes Mother Nature has its own ideas. I have had to put basins on fields that have had continuous no-till and cover crops for 20 plus years. It is important to consult with a conservation professional before making decisions about how to best deal with erosion. The staff at Redwood SWCD has vast knowledge of structural and soil health BMP’s and can be an excellent resource as to what would best fit the scenario. In my years in conservation, I have seen situations where a structure is the solution, other times when soil health is the best course of action, and still others where both options are necessary. My main goal is to determine what is right for you and your farm.