§ 154.029 DRAINAGE AND STORM SEWERS.
   (A)   A storm water management plan shall be required for any new residential, commercial, industrial, institutional or utility development/subdivision having a gross aggregate area of one acre or more.
(`92 Code, § 34-3-15.1)
   (B)   The following rules shall govern the design of improvements with respect to managing storm water runoff:
      (1)   Drainage and storm facilities shall be designed using the modified rationale method or soil conservation service (SCSD) method of calculating runoff discharge rate and total volume.
      (2)   The controlled release rate of storm water runoff from all developments described in division (B) above shall be limited to that which existed prior to development for the design year used.
      (3)   Streets, blocks, lots, parks and other public grounds shall be located and laid out in a manner as to minimize the velocity of overland flow and allow maximum opportunity for infiltration of storm water into the ground and to preserve and utilize existing and planned streams, channels and detention basins.
      (4)   The increased storm water runoff resulting from the proposed development may be accommodated by the provision of appropriate detention facilities including wet and dry bottom reservoirs, flat roofs, parking lots or streets. The following shall govern the design of detention facilities:
         (a)   Storage volume. The volume of storage potential provided in detention facilities shall be sufficient to control the excess storm water runoff, as determined to be the difference between the storm water quantity from the site in its developed state for a ten-year, 24-hour frequency rainfall as published by the state water survey rainfall for this region, less the allowable release rate as set forth in division (C)(2) above. A higher frequency storm may be justified by the village depending upon the particular development conditions.
         (b)   Release rate. At no time during the design storm shall the storm water runoff release rate exceed the allowable release rate as set forth in division (C)(2) above.
         (c)   Release velocity.
            1.   Detention facilities shall release storm water at a non-erosive velocity.
            2.   Protected channels receiving detention discharge shall incorporate features to reduce velocity to non-erosive levels at the point where such discharge enters the unprotected channel. If release is into a subsurface conduit the energy gradient in the receiving facility shall not be increased beyond the slope of the conduit.
         (d)   Accommodations. Every residential subdivision shall be provided with facilities which can satisfactorily accommodate the runoff incident to the ten-year design storm.
(`92 Code, § 34-3-15.2)
Cross-reference:
   Stormwater Drainage, see Chapter 152