However, the Arkansas Department of Environmental Quality regulates this approach since it is considered a liquid waste system. The more commonly used approach is to use vegetative filter strips to treat runoff water. Filter strips are bands of vegetation down-slope of heavy use areas designed to remove sediment and nutrients from runoff water. Filter strips operate by causing solids to settle out of the runoff water, allowing water to infiltrate into the soil and providing opportunities for the plants and soil to process and use nutrients. For filter strips to be effective, the water needs to move as a uniform sheet across the filter strip.
Filter strips lose effectiveness when channelized flows occur.
Filter strips are normally vegetated with grasses that are suitable to the site and that will adequately filter runoff. A filter strip may require some earthwork before seeding. Often, however, existing pasture areas with well-established forage can serve as the filter strip. The width, or length of flow, of a filter strip is based primarily on the slope of the land in the strip. Steeper slopes require wider filter strips.