A. Adequate surface and subsurface drainageways for the removal of stormwater shall be provided by the subdivider. The extent to which storm drainage facilities shall be required will be based upon an analysis of need prepared for the subdivider by a registered professional engineer, and shall be so designed that it may be incorporated into a comprehensive drainage system. The analysis shall be based upon the rational method of computing stormwater runoff using the 1-hour rainfall to be expected at a twenty (20) year frequency. Times of concentration, soil infiltration, soil infiltration rates, and other variable factors to be used in the analysis shall be discussed with and approved by the EAC and planning commission prior to final plat approval.
B. The stormwater sewer system shall be separate and independent of the sanitary sewer system. Surface inlets shall be provided by the subdivider where evidence indicates such a system is necessary. Open ditches are prohibited as a means of providing for storm drainage; or shall meet the conditions of subsection 15.8.7.5B of this chapter.
C. Materials required for storm sewer construction shall satisfy the current requirements of the standard specifications for road and bridge construction for the state. (Ord. 2013-20)