Lined Waterway or Outlet
In areas where grassed waterways are not capable of conveying runoff without erosion occurring, lined waterways or outlet structures are used. These channels are fortified with concrete, stone, or other permanent material in areas where steep grades, prolonged base flow, seepage, or other groundwater contributions produce a volume of runoff that will result in erosion of the groundcover.
Lined outlets are sometimes used at the end of a grassed waterway to effectively discharge the water without causing erosion in the outlet area. In other situations, regular use by people or animals excludes the possibility of maintaining a constant vegetative cover in the waterway, so linings are installed.
