Channels are oftentimes subject to debilitating erosion due to the water contained by the channel walls. Depending on the velocity of the water flow and the frequency and degree of stormwater runoff, severe hydraulic stresses upon the channel can pose significant dangers to the system.
Multiple considerations are necessary to achieve a safe, environmental, and durable channel system:
– Not only must the system be resistant to erosion, but stable under the slope geometry and hydrostatic uplift forces.
– The channel walls must also be somewhat flexible in order to ensure integrity in the face of localized deformations from seasonal factors and sub-base void formation. However, the system must also be sturdy and durable enough to avoid degradation and uplift from the hydraulic forces present.
– System permeability is desirable in some situations to allow natural drainage. A previous channel lining can relieve hydro-static uplift forces, thus stabilizing the system.
Standard soil and grass linings face the danger of erosion from extended water flow. When channels are lined with loose aggregate, even low to moderate forces can gradually remove particles. Poured concrete walls can only perform effectively with construction joints to avoid rigidity and to lessen the dangers of compromise from base material displacement.