(A) An adequate system for the drainage of all surface water within the area being subdivided, including ditches, pipes, culverts, intersectional drains, drop inlets, bridges, and other structures, shall be constructed by the developer. Such drains shall comply as to size with such requirements, conformable to good engineering practice, as the Village Board shall prescribe; provided that such drains in no event shall be less than 12 inches in diameter. Cross drains shall be constructed to accommodate all natural water flow, be built on a straight line and grade, be laid on a firm base but not on rock and be of sufficient length to permit construction of streets and alleys to their required width and grades.
(B) Surface drainage pipes shall be laid with the spigot end pointed in the direction of the flow, and all ends shall be fitted and matched to provide tight joints and a smooth uniform invert. Such pipes shall be placed at a depth below the road bed that is sufficient to avoid dangerous pressure from impact, and the top, in no event, shall be less than one foot below the surface of the road bed.
(C) A culvert or other drainage facility shall in each case be large enough to accommodate potential runoff from its entire upstream drainage area, whether inside or outside the subdivision. The Village Engineer shall determine the necessary size of the facility, based on the provisions of the construction standards and specifications assuming conditions of maximum potential watershed development permitted by the Zoning Code.
(D) The Village Engineer shall also study the effect of each subdivision on existing downstream drainage facilities outside the area of the subdivision. Where it is anticipated that the additional runoff incident to the development or the subdivision will overload an existing downstream drainage facility or flood existing development upstream, the Planning Commission may withhold approval of the subdivision until provision has the village made for the improvement of said potential condition in such sum as the Planning Commission shall determine. No subdivision shall be approved unless adequate drainage will be provided to an adequate drainage watercourse or facility.
(E) Subdivision proposals and other proposed new development be required to assure that all such proposals are consistent with the need to minimize flood damage; all public utilities and facilities, such as sewer, gas, electrical, and water systems are located, elevated and constructed to minimize or eliminate flood damage; and adequate drainage is provided so as to reduce exposure to flood hazards so as to assure that all building sites are reasonably safe from flood hazards.
(F) Lots shall be laid out so as to provide positive drainage away from all buildings and individual lot drainage shall be coordinated with the general storm drainage pattern for the area. Drainage shall be designed so as to avoid concentration of storm drainage water from each lot into areas not designed to handle flood waters. Lot drainage plans shall conform to the drainage study required for submittal approval.
(Ord. 2009-04, passed 4-23-2009)