Temporary stream crossings of intermittent and perennial streams used only for and during construction shall be designed to convey a two-year flood (minimum) or other flood event approved by the Chief Subdivision Engineer without overtopping unless a more frequent design event is allowed by the Chief Subdivision Engineer. The entire crossing shall be designed to withstand hydrodynamic forces and erosive forces up to the base flood event without washing out. Ephemeral streams may be crossed at temporary at-grade crossings provided that the crossing point is stabilized with materials resistive to the erosive forces produced by runoff from the upstream drainage area, and the design is approved by the Chief Subdivision Engineer. Temporary stream crossings shall be removed upon completion of construction activities. All temporary stream crossing shall be completely removed and the stream restored to its preconstruction condition upon completion of construction. Restoration shall incorporate appropriate vegetation consistent with the adjacent existing vegetation prior to construction or in accordance with a restoration plan approved by the Chief Subdivision Engineer.
(Ord. 10-164, passed 6-17-2010)