(A) Drainage into wetlands, rivers, streams, lakes, ponds and depressional storage areas. Wetlands, lakes, ponds and depressional storage areas shall be protected from damaging modifications and adverse changes in runoff quality and quantity associated with land developments.
(B) Loessal soils. Care must be taken to avoid open flow discharges of stormwater over silt (loessal) soils due to high potential for erosion.
(C) Sinkholes, karst area. The following requirements apply for new developments or redevelopments where sinkholes are determined to be present:
(1) A stormwater detention basin shall not be placed in or over a sinkhole or located closer than 100 feet from the rim of a sinkhole;
(2) The outflow from a stormwater detention basin, channel, ditch or any stormwater runoff generated as a result of a new development or redevelopment shall not empty into or be directed, redirected by any means into or through any sinkhole;
(3) If, after the review of the stormwater drainage plan, the code enforcement officer and/or City Engineer may determine that more detailed information is required, a sinkhole evaluation may be required. A sinkhole evaluation, which addresses the geologic, engineering and environmental factors resulting from a new development or redevelopment, shall be performed by a professional with experience and expertise in karst topography who shall certify the results of the evaluation. This evaluation shall be the responsibility of the applicant and performed at no cost to the city. After a review of this evaluation and with the consultation of the County Soil and Water Conservation District, the Administrator may either approve or disapprove the drainage plan as submitted;
(4) Whenever a new sinkhole appears or it becomes apparent that the sinkhole has not yet been identified, it shall be reported to the County Soil and Water Conservation District.
(D) Special management areas. The city may require additional stormwater control measures for stormwater discharges to special management areas including, but not limited to:
(1) Water bodies listed as “impaired” on Illinois' Clean Water Act 303(d).305(b) Integrated List.
(2) Any water body or watershed with an approved total maximum daily load (TMDL).
(3) Critical areas with sensitive resources (e.g., karst areas, groundwater recharge areas highly vulnerable to contamination, drainage areas to water supply reservoirs, source water protection zones, etc.)
(E) Sump pump drainage. It is illegal to discharge groundwater from sump pump to sanitary sewer, across property lines, across sidewalks, and to city streets. Direct discharge into the city storm sewer is the best location, so as part of the storm sewer system, sump pump collection systems are required in all new developments. Sump pump collection systems shall consist of:
(1) The pipe system for sump pump drainage shall consist of six-inch diameter SDR 35 PVC pipe at a minimum depth of 36 inches.
(2) A cleanout shall be located every 400 feet or less, at every change in direction, and at every junction of two or more pipe mains.
(3) The sump pump collection piping system shall be located in the front yards. It will be connected to the stormwater drainage conveyance system within the subdivision at appropriate intervals not exceeding 500 feet. The pipe slope shall be a minimum of 0.25%.
(4) All service lines to the main shall be privately owned and maintained and shall be a one and a half inch diameter Schedule 40 PVC pipe. Homeowners are responsible for burying their sump pump line from the house to the collection system. The discharge pipe must have a check valve within one foot of the floor grade and at a union or other approved coupling for easy disconnection for repair and replacement.
(5) The sump pump collection system main shall be located in a utility easement dedicated to the city.
(6) All connections to the sump pump drainage system main shall be a tee fitting cut into the main and inspected by the code enforcement official.
(7) The sump pump drainage pipe is intended for sump pump drainage only. Surface drainage shall not be allowed into the pipe.
(8) All newly constructed buildings are required to connect to the sump pump drainage system. The owner/developer shall install THWN soft drawn solid No. 12 copper tracer wire that is taped on the side of the pipe at ten-foot intervals (minimum) and provide double length loop inside half-inch CPVC conduit extending eight inches above the ground surface at cleanouts.
(9) In the rare case where a collection pipe is not feasible, the City Engineer may approve sump pump discharge at grade within five feet of the building if the discharge is contained within the property and will not cross property lines.
(F) Roof drains. Roof drains may discharge at grade within five feet of the property line with a “pop-up” drain emitter. The city may allow roof drain connections in manholes by permit only.
(Ord. 2017-03, passed 3-6-2017)