(A) All drainage facilities, including on-site detention, storm sewer systems, drainageways, floodplains, detention ponds and drainage channels, shall be shown on a drainage plan and approved by the City Council with the recommendations of the Planning and Zoning Commission and the Director of Public Works or his or her designee. The developer may be required to expand the drainage plan to include other properties within the drainage basin when the city determines the potential exists for impact beyond the development area, both upstream and downstream.
(B) The plan shall provide the following information:
(1) Existing and proposed contour lines and the surface water drainage system, including any major alteration of the existing drainage pattern. Drainageways and detention ponds shall be designed for a 25-year storm occurrence. The contour interval shall be of such detail that the final drainage pattern is adequately illustrated;
(2) The boundaries of all drainage easements and detention ponds. A maintenance agreement for the upkeep of the detention ponds shall be filed with the plat;
(3) Individual lot drainage shall be coordinated with the general surface drainage pattern for the area. Drainage shall be designed so as to avoid a concentration of storm drainage water from each lot to adjacent lots; and
(4) Any other information or drainage plans that the Planning and Zoning Commission shall require.
(C) Wherever possible, the developer shall utilize existing city storm sewers. Detention ponds shall be discouraged, but may be allowed when no other reasonable alternative exists. Any such pond shall be designed for the absolute minimum term of storage, not to exceed three days.
(Prior Code, § Q-12-601)