Roadside Guide to Michigan Plants, Trees, and Flowers by Edwin Arnfield

Water quality is improved because less soil and sediment is moved from the field to to nearby streams and water enters those streams more gently. This reduces the force of the water over the land and therefore reduces erosion. The wide, sloping channel spreads water out as it flows. This year to year grass acts as a stable pathway for runoff water to follow. They are broad, rounded swales that are planted permanently in grass instead of rotated through crops like corn and soybeans. They can either prevent erosion before it happens or fix minor erosion that has already started. Grass waterways are planted in the natural depressions where water tends to flow. Oftentimes this happens when there are not enough plants growing to hold the soil in place. Over time, this concentrated flow of water can chisel away at the land, forming small channels called rills, or larger channels called gullies.

How Grassed Waterways WorkĪs water flows downhill, it tends to gather in natural depressions in the land.

The plants growing in these contoured pathways help slow the flow of water and the plant roots help to hold the soil in place. They are designed to carry water down a hill while also preventing erosion. They are planted with permanent vegetation, meaning they might be mowed, but the plants are never plowed or killed intentionally. Grassed waterways (sometimes also called grass waterways) are wide, shallow channels that are installed where water runoff usually concentrates in an agricultural field.

Roadside Guide to Michigan Plants, Trees, and Flowers by Edwin Arnfield