When permanent structures are required to control storm water run-off during and after construction on sites the following shall apply:
   (A)   Depending on the project layout, a diversion shall be constructed across a slope less than 15% to:
      (1)   Prevent run-off from higher areas having a potential for causing erosion and thereby interfere with the establishment of vegetation on lower areas; and
      (2)   Reduce the length of slopes to minimize soil loss.
   (B)   Diversions need be constructed only below stabilized or protected areas.
   (C)   Outlets from diversions shall be constructed to discharge in a manner as not to cause erosion.
   (D)   Outlets shall be constructed and stabilized prior to the operation of diversions.
   (E)   Storm drain outlet protection shall be provided when converting pipe flow to channel flow.  The reduction in velocity shall be sufficient to slow the flow of water and dissipate the energy of discharge equal to the receiving waterway.  The reduction in velocity may be accomplished by providing mortared riprap stabilization, providing energy dissipaters or providing permanent vegetation, depending on specific needs.
(Ord. 3055, passed 12-21-99)