Grassed waterways are natural or constructed channels shaped to required dimensions and lined with suitable vegetation for stable conveyance of runoff. Grass-lined water conveyance channels are widely used to convey excess runoff water where flows are of a sufficiently short duration to allow the grass to withstand the inundation period and operation is sufficiently infrequent to allow healthy grass cover to be maintained.

This type of channel may be used for diversions, spillways, and floodways, as well as for waterways to convey local runoff. A constructed waterway is designed to carry the estimated flow without damage to the waterway or its lining, and should be planned and designed to fit the conditions of a particular site.

Topics: Introduction Assessment of suitability Legal/regulatory considerations Planning and preliminary design considerations Location Slope Cross-section shape Vegetation Outlets Sediment control Data collection Design process Initial design parameters: slope, discharge, section, and lining Conditions for stability Sizing channel sections Use of the design tables for parabolic and trapezoidal channels Layout and construction Appurtenant structures Site preparation Excavation Filter fabric barriers Post-construction protection of channel lining Maintenance Removal of sediment Repair work

Intended Audience: This course is intended for Water Resources, Civil, Environmental, Transportation, and other engineers whose job description requires a general knowledge of grass-lined or vegetative water conveyance channel design.

Publication Source: USDA (Natural Resources Conservation Service)