(A) Erosion shall be controlled by limiting velocities, changing the channel lining or reshaping the channel to spread the flow of runoff. Methods of controlling erosion in open channels, include the following: grass covers or sod; aggregate channel lining; gee-textile turf reinforcement mats (“TRMs”) and rolled erosion control products (“RECPs”); reinforced concrete or pre-cast paving; and bioengineering practices. Design velocities should generally be greater than one and one-half feet per second to avoid excessive deposition of sediments. When flat slopes are unavoidable, concrete paving shall be used to accelerate runoff.
(B) Channel linings shall be designed to control erosive flows resulting from the ten-year storm. The design of channel linings shall meet both the velocity and shear stress requirements.
(C) Consideration shall be given for the construction of other methods of lining for erosion control, including check dams, drop structures, gabions or other methods subject to approval of the approving agency.
(D) For vegetated or natural channels, 2% slopes are preferred, but the minimum slope shall be 1%. For hardened concrete channels, the minimum slope shall be 0.5% unless otherwise specifically approved by the approving agency on a case-by-case basis.
(Ord. 012-118, passed 10-8-2012)