(A) Waterways.
(1) Every effort shall be made to retain the natural drainage systems in the city including existing wetlands and ponds. Aboveground runoff disposal waterways may be constructed to augment the natural drainage system.
(2) The widths of a constructed waterway shall be sufficiently large to adequately channel runoff from a ten-year storm. Adequacy shall be determined by the expected runoff when full development of the drainage area is reached.
(3) No fences or structures shall be constructed across the waterway that will reduce or restrict the flow of water.
(4) The banks of the waterway shall be protected with permanent vegetation.
(5) The banks of the waterway shall not exceed one foot vertical for every four feet horizontal in gradient.
(6) The gradient of the waterway bed shall not exceed a grade that will result in a velocity that will cause erosion of the banks of the waterway.
(7) The bend of the waterway shall be protected with turf, sod or other City Engineer approved materials.
(8) If the flow velocity in the waterway is such that erosion of the turf side wall will occur and the velocity cannot be decreased via velocity control structures, then other City Engineer approved materials may replace turf on the side walls. Either gravel or riprap would be allowed to prevent erosion at these points.
(B) Sediment control of waterways.
(1) To prevent sedimentation of waterways, pervious and impervious sediment traps and other sediment control structures shall be incorporated throughout the contributing watershed.
(2) Temporary pervious sediment traps could consist of a construction of bales of hay with a low spillway embankment section of sand and gravel that permits a slow movement of water while filtering sediment. The structures would serve as temporary sediment control features during the construction state of development. Development of housing and other structures shall be restricted from the area on either side of the waterway required to channel a 25-year storm.
(3) Permanent impervious sediment control structures consist of sediment basins (debris basins, de-silting basins or silt traps) and shall be utilized to remove sediment from runoff prior to its disposal in any permanent body of water.
(Ord. 879, passed 10-28-2020)