Establishing trees, shrubs, and grasses helps replace the natural system that once protected most Iowa streams, creeks, and rivers. As runoff flows over land, the tall, dense stems of native grass slows it down, allowing waterborne soil particles to drop into the buffer zone rather than getting to the stream. The root systems of some grasses may penetrate up to 6 feet, providing deep pores for water to soak into rather than running off. And the mass of roots deep beneath the soil's surface provides an abundance of organic matter. This organic matter provides an ideal environment for microbes that break down the chemicals through natural processes.
Shrubs have woody stems that obstruct runoff flowing into the stream and help slow floodwaters.
Slowing down the flow of water allows sediments to settle out, cleaning the water. Trees near the stream's edge offer similar soil and stream-bank protection. Their dense root mass stabilizes stream banks. The deep roots of shrubs and trees also take up nutrients before they reach the stream. There are other proven benefits to establishing a riparian buffer system.