All developments shall:
   (A)   Extend the storm sewer system through the proposed development to serve upstream properties in the natural drainage area. The storm sewer system should reflect the ultimate development of the drainage area.
   (B)   Provide a stormwater drainage system that consists of a minor drainage system, a major drainage system and an emergency overland flow route.
   (C)   The storm sewer drainage system is assumed to consist of such components as sewers, channels, swales, natural drainageways, inlets, catch basins, manholes, streets, detention/ retention basins, and other necessary facilities.
   (D)   The engineering plans shall have a certification by a registered professional engineers as follows:
"I,         , hereby certify that adequate stormwater storage and drainage capacity has been provided by this development, such that surface water from the development will not be diverted onto and cause damage to adjacent property for storms up to and including the one hundred (100) year event, and that the design plans are in compliance with all applicable federal, state, county, and village laws and ordinances."
   (E)   The storm sewer system shall be entirely separate from the sanitary sewer system.
   (F)   Storm sewers shall be designed to convey the peak flow from a ten-year rainfall event with a hydraulic grade line that is entirely within the pipe. Rainfall frequency data shall be obtained from Appendix A, Table 1. Storm sewers and outfalls shall be designed to function at their design capacity during flooding conditions on the receiving stream or other body of water.
      (1)   At the discretion of the Stormwater Administrator, private industrial storm sewer may be designed with the hydraulic grade line up to 1 foot below the rim elevation. Any sewer that conveys offsite flows or flow from more than 1 acre of tributary area are not allowed to surcharge with this condition.
   (G)   The storm sewers shall be a minimum of 12 inches in diameter and shall be constructed of reinforced concrete pipe only.
   (H)   No ditch system shall be permitted. The minor drainage system shall be constructed so that the drainage from each lot or parcel is conveyed entirely through storm sewer pipe.
   (I)   The major drainage system may be permitted to flow over roadways, rear yard and side yard swales, and other open conveyances as long as the maximum depth of ponding or flow is no more than nine inches at any location and the maximum water surface elevation is a least one foot below the lowest opening of any nearby structure. The design of the major drainage system may account for the minor drainage system (storm sewers) to be fully functional. No flow is allowed over the road, perpendicular to the roadway.
   (J)   Rear yard and side yard swales shall meet the following conditions
      (1)   The maximum side slopes shall be a six to one (6:1) ratio.
      (2)   The appropriate easements are provided, a minimum of 20 feet wide.
   (K)   Inlets on roadways shall be located as necessary to collect surface water, but spacing shall not exceed a maximum of 400 feet. Catch basins shall be placed before a storm sewer enters a manhole. Manholes shall be located at the junction of two or more storm sewer pipes or at any change in grade alignment or size of pipe. Maximum spacing of manholes shall be 400 feet.
   (L)   All storm sewers shall use materials, and be installed in the manner meeting or exceeding the requirements, standards, and specifications contained in the "Standard Specifications for Water and Sewer Main Construction in Illinois," the most current edition as amended, supplemented and amended by the Village Engineer. These standards and specifications, with the modifications, amendments, and amplifications of the Village Engineer, are available for purchase or inspection and review in the office of the Village Engineer.
   (M)   All public storm sewer must be televised with said recording submitted to the Department of Public Works prior to acceptance of all projects.
   (N)   At the discretion of the Stormwater Administrator, dual inlets are required at low points in public roads.
(Ord. 06-0383, passed 3-15-06; Am. Ord. 19-1532, passed 1-16-19)