The hills dry out and we get to work installing geotextiles, planting hill-holding grasses, reevaluating drainage patterns. Can't avoid the water here, even if ditches, swales and creeks happen to be dry most of the year. Long periods of dry weather further complicate plant selection. Vegetation is clearly the cheapest and most effective way to stabilize slopes and keep erosion under control. Erosion occurs when rain drops strike unprotected soil and break off particles of soil that may then be carried away by the accumulated flow.
Vegetation protects the soil from raindrop impact.
Erosion is further reduced by the irregular configuration of the streambed when vegetation lines it. Water passing over is slowed and turbulence reduced at the soil-water interface by the influence of flexible grasses. The complex of roots stabilizes the soil while the plants, themselves, absorb quantities of water that are later lost to evapotranspiration through leaves. Getting Grass Going Growing a sustainable stand of the right vegetation will depend on each situation. In a dry swale that sees water only occasionally as a result of weather, the plants chosen must establish before the next damaging rain event and be able to withstand the assault of rapid water flows.