§ 159.308  ADDITIONAL WATER QUANTITY CONTROL STANDARDS.
   (A)   Applicability.  This section applies to the following type developments or redevelopments:
      (1)   All non-residential sites containing new development and/or redevelopment including road construction, grading, paving, gravel placement, and construction of buildings and other structures, which include the creation of 20,000 square feet or more of new impervious area, within the corporate limits and the extraterritorial jurisdiction of the City of Monroe. Impervious areas in existence prior to the effective date of this Ordinance shall not be included in the computation of impervious area; and
      (2)   All new residential development and/or redevelopment meeting the following requirements:
         (a)   Exceeds 1 dwelling units per acre;
         (b)   Provides for private or public street/driveway construction for access to multiple lots;
         (c)   Requires engineered stormwater control structures as outlined by this Ordinance.
      (3)   Properties that directly abut regulated floodways as designated by the Federal Emergency Management Agency shall be considered exempt from requirements of this section.
   (B)   General requirements.
      (1)   The engineer or landscape architect of record shall conduct hydrologic and hydraulic engineering studies for the site for both pre-development and post-development conditions. The engineer or landscape architect of record shall provide a certification that the development or redevelopment will not cause increased off-site flooding, drainage, or erosion problems.
      (2)   Where it is determined that the development of the site does increase the peak discharge rate, stormwater quantity control improvements must be implemented. The stormwater quantity control improvements must limit the two-year and ten-year post-development peak discharge rates to pre-development peak discharge rates, to minimize flooding, drainage, and erosion problems. These improvements may consist of nonstructural approaches such as natural swales, depressions in the land and other natural approaches, or structural approaches such as detention structures (wet and dry basins), extended detention facilities and alternative best management practices (BMPs) with provisions for stormwater quantity control. A combination of nonstructural and structural approaches is encouraged.
      (3)   For stormwater management improvements proposed to achieve compliance with quantity control requirements of this section, a hydrologic-hydraulic analysis of the site drainage system in the pre-development condition and the post-development condition shall be performed. The analysis should be included with the stormwater management plan and should demonstrate that the quantity control requirements stated in this section will be achieved by the proposed improvements. These improvements shall be subject to review and approval by the Stormwater Administrator.
      (4)   If site characteristics indicate that complying with the minimum stormwater management requirements of this section will not provide adequate engineering designs or protection for local residents, and downstream property, it shall be the site designer's responsibility to exceed the minimum requirements as necessary.
(Ord. O-2007-24, passed 9-18-07)