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For proposed structures located outside the regulatory floodplain, the lowest opening shall be above the FPE (unless allowed in accordance with the regulations stated in this subchapter), including doors, access ways and window wells, as depicted on the building plans reviewed and enforced by the Building and Zoning Official.
(Ord. 2019-03, passed 4-15-2019)
These standards apply to riverine regulatory floodplains without a delineated floodway.
(A) The applicant shall obtain approval from IDNR-OWR for development of more than five acres or subdivisions of more than 50 lots located, entirely or partly, within the regulatory floodplain (without a delineated regulatory floodway).
(B) The development shall not singularly or cumulatively result in an obstruction of flood flows or potential flood damages outside the site due to an increase in flood heights, velocities or loss of floodplain area storage.
(C) If the riverine floodplain without a delineated floodway is in a Zone A with no BFEs shown, then a professional engineer shall submit a study that:
(1) Determines a BFE and demonstrates that the proposed development will maintain the existing conditions conveyance, will not increase flood velocities, will not increase flood profiles and will compensate for any lost floodplain storage in accordance with this subchapter; or
(2) Shows that the proposed development will meet the requirements for regulatory floodplains within this subchapter.
(Ord. 2019-03, passed 4-15-2019)
The following standards apply within the regulatory floodplain.
(A) Hydraulically equivalent compensatory storage volume will be required for development in a riverine regulatory floodplain, and shall be at least equal to the regulatory floodplain flood storage volume displaced, multiplied by one, within the incorporated areas. The storage volume displaced below the existing ten-year-frequency-flood elevation must be replaced below the proposed ten-year-frequency-flood elevation. The storage volume displaced above the existing ten-year-frequency flood elevation must be replaced above the proposed ten-year-frequency-flood elevation.
(B) Compensatory storage volume for development in a non-riverine regulatory floodplain area that is also adjacent to a lake shall be equal to the storage volume displaced.
(C) Compensatory storage volume requirements for development in a non-riverine regulatory floodplain that is not adjacent to a lake shall be replaced in accordance with the requirements for the loss of depressional storage as identified within this subchapter.
(D) Compensatory storage areas shall be designed to drain freely and openly to the channel, and shall be located adjacent to the development. This standard does not apply to non-riverine regulatory floodplain or the replacement of depressional storage.
(E) A recorded covenant running with the land shall be required to maintain the compensatory storage volume in areas modified to provide compensatory storage volume.
(Ord. 2019-03, passed 4-15-2019)
These standards are for the reconstruction, modification or new construction of bridges, culvert crossings and roadway approaches that are located within the regulatory floodplain.
(A) A proposed new structure shall not result in an increase of upstream flood stages greater than one-tenth foot, when compared to the existing conditions for all flood events, up to and including the base flood event, unless contained within the channel banks or recorded easements. The evaluation must be submitted to IDNR-OWR for review and issuance of a permit.
(B) If the proposed new structure will increase upstream flood stages greater than one-tenth foot, the applicant must contact IDNR-OWR for a dam safety permit or waiver. The Administrator shall be copied on all related correspondence.
(C) A restrictive bridge or culvert may be altered to increase the conveyance of the base flood, if an impact analysis is completed and approved in writing by the Administrator, and all other required regulatory approvals are obtained.
(D) Velocity increases must be mitigated by use of appropriate measures to avoid scour, erosion and sedimentation at the structure.
(Ord. 2019-03, passed 4-15-2019)
(A) Before any development in or near waters of the U.S., or in or near a wetland delineated on the NRCS Wetland Inventory Maps, U.S. Fish and Wildlife Service National Wetland Inventory Map, or if the Administrator considers that a wetland is present through visual inspection, a written report identifying and evaluating the boundaries, location, limits, area and quality of all onsite wetlands shall be submitted. The presence and limits of wetland areas shall be determined by a wetland delineation conducted in accordance with the 1987 Corps of Engineers Wetland Delineation Manual. Before any development on agricultural land, in addition to the onsite delineation required under the provisions listed herein above, a farmed wetland delineation conducted in accordance with the National Food Security Act Manual methodology must be performed.
(B) The quality of the wetlands shall be evaluated based upon the Flora Quality Index (FQI).
(C) The approximate location, extent and relative quality of wetlands within 50 feet of the site shall be identified and included in the written report, if the wetland is downstream of the development such that the run off could negatively affect the quality or health of the wetland. The location and extent of such offsite wetlands shall be determined by using the first of the following documents or procedures pertaining to such wetlands at the time of development:
(1) Site-specific delineation;
(2) Wetlands identified in watershed plans or ADID studies. If such plans are not available, then;
(3) Wetlands identified in interim watershed plans. If such plans are not available, then;
(4) Wetlands identified on NRCS wetlands inventory maps. If such maps are not available, then;
(5) Wetlands identified on the United States Fish and Wildlife Service National Wetlands Inventory maps.
(D) Final FQI assessments made before June 1 or after October 15, unless allowed at the discretion of the Administrator, shall be considered to be preliminary. Buffer requirements shall be based upon such assessments.
(E) All wetland mitigation required under a COE Section 404 permit for wetland disturbances in the village, shall be provided for. All wetland mitigation required under this subchapter for wetland impacts in the village shall be provided for in the same watershed where the wetland disturbances occurred.
(Ord. 2019-03, passed 4-15-2019)
Preserved wetlands shall be protected during development such that an FQI calculated upon completion of the project or two years after the commencement of development, whichever is later, will not be more than two points less than the FQI originally calculated. The developer shall mitigate for any wetland not so preserved at the ratio required for in the FQI originally calculated.
(Ord. 2019-03, passed 4-15-2019)
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