(A) The drainage system for a parcel containing the proposed construction site shall be designed to restrict the peak rate of discharge from the total parcel (one-hour storm once a year) to pre-project levels. The Zoning and Building Director, or his or her designee, may require the petitioner to provide pre- and post-project peak discharge rates, showing the peak flows and retention/detention rates using accepted methodology, including the Illinois Urban Manual. If the post-development peak discharge rate must be reduced, the Zoning and Building Director, or his or her designee, will recommend appropriate stormwater control options. If a mutually-acceptable option cannot be developed, the appeal process outlined in §§ 152.140 through 152.142 will be followed. The issuance of a grading and drainage permit shall constitute an authorization to do only that work which is described on the approved sketch. A Class 2 grading and drainage permit shall be valid for one year after the date of issuance.
(B) Any construction that meets one of the following thresholds shall require a Class 2 grading and drainage permit.
(1) Any construction that will include the addition of an impervious surface area (for example, streets, roof, patio, or parking area, or any combination thereof) greater than or equal to 10,000 square feet and less than one acre (43,560 square feet).
(2) Any land disturbing activity (for example, clearing, grading, stripping, excavation, fill, or any combination thereof) that will affect an area greater than or equal to 10,000 square feet and less than one acre (43,560 square feet).
(3) Any land disturbing activity that will exceed 100 cubic yards, but does not otherwise require a Class 3 grading and drainage permit.
(4) Any land disturbing activity on the sloping side of the slope disturbance line, but does not otherwise require a Class 3 grading and drainage permit.
(Ord. passed - -; Ord. passed 1-21-2014)