Grass swales, or dry swales, are designed to transport stormwater, promote infiltration, and capture sediment during a storm event. Grass swales are turfgrass-planted channels constructed with wide bottoms to encourage infiltration of stormwater into the underlying soil. Vegetation in the channel functions to reduce the speed of stormwater and trap sediment as water is conveyed through the channel. When functioning properly, these swales hold water no longer than six hours after a storm and should remain dry until the next storm event.