(A) Definition. A drainageway is a course of running water, either perennial or intermittent, flowing in a channel.
(B) Purpose. Drainageways serve in the transporting of surface runoff to downstream areas. As such, drainageways serve to carry surface waters, supplement floodplain, wetland, and water storage functions in heavy storm or melt events, filter water-borne pollutants and sediments, promote infiltration and groundwater recharging, and provide a unique habitat at the land/water margin. Drainageway protection requirements preserve each of these functions as well as greatly reduce the potential for soil erosion along drainageways by protecting vegetative groundcover in areas which are susceptible to variable runoff flows and moderate to rapid water movement.
(C) Determination of presence.
(1) Drainageways are to be determined by using the definition of
DRAINAGEWAY as set forth in § 154.015 and the sources in the order indicated below. If the first source is considered inaccurate or inappropriate, as determined by the Zoning Administrator, the succeeding source shall be used:
(a) A topographic survey prepared at the petitioner's expense by and certified by an Illinois registered land surveyor at a contour interval of not less than two feet.
(b) Topographic maps on file with the city.
(c) U.S.G.S. 7.5 minute topographic quadrangle maps.
(2) The area of drainageways (in square feet and acres) shall be measured and graphically delineated on the Natural Resource Protection Plan.
(D) Protection standards. Drainageways shall be protected as indicated on Table 154.503.1. Protected portions of drainageways shall remain in an undisturbed state except for the land use permitted per the requirements of § 154.404.
(E) Mitigation. Drainageway mitigation may be permitted under the requirements of the Illinois State Statutes, and administrative rules promulgated by the Illinois Department of Natural Resources (IDNR). If such statutes or rules do not provide sufficient guidance on required mitigation, the city shall require the preparation and submittal of a wetland mitigation plan by a professional wetland mitigation specialist, and the petitioner shall be responsible for all costs necessary for the city to conduct a professional review of the mitigation plan. In addition, a permit from the U.S. Army Corps of Engineers pursuant to the requirements of section 404 of the Clean Water Act (33 U.S.C. 1344) and/or the IDNR shall be submitted to the city certifying that the filling has been approved and permitted by the Corps and/or IDNR. Alternatively, the applicant must obtain and provide to the city written correspondence from said agencies that a state or federal permit is not required, as a condition of city review.
(Ord. O-05-04, passed 4-11-05)