The required channel cross section and grade are determined by the design capacity, the material lining the channel, and the requirements for maintenance. A minimum depth may be required to provide adequate outlets for subsurface drains, tributary ditches or streams. The channel grade shall be such that the velocity in the channel is high enough to prevent siltation but low enough to prevent erosion and maintain channel stability. Velocities less than 1.5 feet per second should be avoided because siltation will take place and ultimately reduce the channel capacity.
(Ord. 1999-05, passed 6-8-99)