(a) Generally. The Subdivider or Condominium Developer (as applicable) shall construct stormwater drainage facilities adequate to serve the Subdivision, Certified Survey Map, or Condominium in conformance with Section 14-1-74; all applicable local comprehensive plans or adopted plan components; or as required by the Village of Edgar under both Title 15, Chapter 2 "Construction Site Erosion Control" and Chapter 3 "Post-Construction Stormwater Management Code", based upon the recommendations of the Village Engineer. These facilities may include curbs and gutters, catch basins and inlets, storm sewers, road ditches, open channels, water retention and detention structures, basins, and settling basins. All such facilities shall be of adequate size and grade to hydraulically accommodate the maximum potential volumes of flow and shall be so designed as to prevent and control soil erosion and sedimentation and to present no hazards to life or property. In addition, the following provisions shall be complied with.
(b) Stormwater Management Plan Required. A stormwater management plan shall be prepared by a Wisconsin registered professional engineer which shall include, but not be limited to, the following:
(1) Existing and proposed topography at two (2) foot contour intervals of the proposed Subdivision, Certified Survey Map, or Condominium.
(2) Proposed elevations of all streets.
(3) Proposed drainage swales.
(4) Proposed storm sewers, manholes and inlets.
(5) Construction site erosion facilities.
(6) A report and map(s) showing the drainage basin for the entire area where the Subdivision, Certified Survey Map, or Condominium is located, including estimates of the total acreage in the drainage basin and percentage of the drainage basin within the proposed Subdivision, Certified Survey Map, or Condominium.
(7) Location of any planned stormwater detention and/or retention basins and applicable calculations for their sizing and design.
(8) Calculations relating to the amount of runoff from the site of the proposed Subdivision, Certified Survey Map, or Condominium prior to development and anticipated runoff following the development of the site.
(c) Unpaved Street Gutters (Ditches).
(1) Unpaved street gutters (ditches) may be permitted by the Village Board, upon the recommendation of the Village Engineer, and shall be shaped and seeded and/or sodded as grassed waterways.
(2) The Subdivider or Condominium Developer (as applicable) is encouraged to use natural wetland plant materials where possible.
(3) Where the velocity of flow is in excess of four (4) feet per second on soils having a severe or very severe erosion hazard and in excess of six (6) feet per second on soils having moderate, slight, or very slight erosion hazard, the Subdivider or Condominium Developer (as applicable) shall meander the waterway or install a paved invert or check dams, flumes, or other energy dissipating devices.
(d) Drainage Facilities.
(1) These shall, if required by the Village Engineer, include stormwater detention and/or retention basins, structures, and settling basins necessary so as to prevent erosion and sedimentation where such facilities discharge into streams or lakes.
(2) The design criteria, the size, type, grades, and installation of all stormwater drains and sewers and other cross-section, invert, and erosion control paving check dams, flumes, or other energy dissipating structures and seeding and/or sodding of open channels and unpaved road ditches proposed to be constructed shall be in accordance with the plans and standard specifications approved by the Village of Edgar.
(e) Storm Sewers.
(1) When required by the Village, the Subdivider or Condominium Developer (as applicable) shall assume the cost of installing all required storm sewers within the proposed Subdivision, Certified Survey Map, or Condominium except for the added cost of installing storm sewers greater than those which are necessary to serve tributary drainage areas lying outside of the proposed Subdivision, Certified Survey Map, or Condominium.
(2) The cost of such larger storm sewers shall be prorated in proportion to the ratio which the total area of the proposed Subdivision, Certified Survey Map, or Condominium is to the total drainage area to be served by such larger sewer, and the excess cost shall either be borne by the Village of Edgar or assessed against the total tributary drainage area. Storm sewers oversized to handle runoff from offsite properties will be installed by the Subdivision, Condominium or Certified Survey Map Developer (as applicable); however, the cost of oversizing above a twenty-four (24) inch diameter storm sewer typically shall be paid by other users connecting to the system.
Cross-Reference:
Section 14-1-74, Drainage and Stormwater Management System.