What should be placed between runoff and a pond if diversion of surface runoff is not possible?

Grass filter strips are an effective choice for managing runoff and protecting water bodies like ponds. These strips consist of native grasses and vegetation that act as a natural filtration system, absorbing and slowing down runoff before it reaches the pond. This process allows for sediments, nutrients, and potential pollutants carried in the runoff to settle out, thereby improving water quality and reducing the risk of contamination in the pond.

The grass filter strips not only help in reducing the velocity of the runoff but also provide habitat for wildlife, enhance aesthetic value, and contribute to the overall health of the aquatic ecosystem. Their capacity to absorb moisture and filter pollutants makes them a preferred solution in scenarios where direct diversion of surface runoff is not feasible.

Other options like retention walls, riprap, and sandbags serve specific purposes, such as erosion control or temporary barriers, but they do not offer the same long-term environmental benefits and pollutant filtration that grass filter strips provide.