15.36.280 DRAINAGE. 
   A.   Benches at least six feet wide shall be installed on all cut and fill slopes at not more than twenty-foot vertical intervals.
   B.   All benches shall have city standard concrete V-ditches for drainage. The ditches shall have a minimum gradient of five percent and a maximum gradient of forty percent.
   C.   All natural embankments adjacent to or within residential lots twenty feet or more in height shall have benches and V-ditches near the bottom of the slope to prevent runoff from the embankment from flowing onto the residential lot.
   D.   Runoff shall not be allowed to flow over the top of a slope onto the slope face.
   E.   Drainage facilities must discharge into existing manmade drainage facilities or into natural channels subject to the approval of the director of public services.
   F.   Drainage facilities must be designed to handle as a minimum the runoff computed in accordance with the requirements and standards of this chapter as specified for runoff calculations which must accompany the grading plan.
   G.   Building pads must slope a minimum of two percent toward drainage facilities.
   H.   All drainage devices not accepted for maintenance by the city must be maintained by the property owner. (Ord. 486(part), 1986).