Loading...
Ordinance 2002-40 i STATE OF ILLINOIS ) Rev.11/06/02 ss COUNTY OF KENDALL ) ORDINANCE NO. 2002- `{0 ORDINANCE AMENDING UNITED CITY OF YORKVILLE SUBDIVISION (ORDINANCE NO.2000-2) AND UNITED CITY OF YORKVILLE STANDARD SPECIFICATIONS FOR IMPROVEMENTS (RESOLUTION NO. 2000-4) Ott SECTION 1: APPLMABILTtY For all development governed by the Yorkville Subdivision Ordinance and/or Yorkville Standard Specifications for Improvements, the definitions and requirements listed below shall apply. SECTION 2: DEFINITIONS Compensatory Storage: An artificially excavated, hydraulically equivalent volume of storage within the floodplain used to balance the loss of natural flood storage capacity when fill or structures are placed within the floodplain. Depressional Storage: Localized low areas which are hydraulically disconnected from and have no positive outfall to any creek, stream, or river. For the purposes of this ordinance, depressional storage areas shall also be referred to as non-riverine floodplains. Floodplain: That land adjacent to a body of water with ground surface elevations at or below the base flood or the 100-year frequency flood elevation. The floodplain is also known as the Special Flood Hazard Area. One Hundred-Year Event: A rainfall, runoff, or flood event having a one percent chance of occurring in any given year. 1 SECTION 3: REOUIlMEMENTS 1. Compensatory storage shall be provided for all storage lost or displaced in the floodplain due to development. a) Hydraulically equivalent compensatory storage requirements for fill or structures in a riverine floodplain shall be at least be equal to 1.5 times the volume of floodplain storage lost or displaced. Such compensation areas shall be designed to drain freely and openly to the channel and located opposite or adjacent to fill areas. A recorded covenant running with the land is required to prohibit any modification to the compensation area. The floodplain storage volume lost below the existing 10-year frequency flood elevation must be replaced below the proposed 10-year frequency flood elevation. The floodplain storage volume lost above the existing 10-year frequency flood elevation must be replaced above the proposed 10-year frequency flood elevation. b) Hydraulically equivalent compensatory storage requirements for fill or structures in a non-riverine floodplain shall be at least equal to 1.0 times the volume of non- riverine floodplain storage lost or displaced. A recorded covenant running with the land is required to prohibit any modification to the compensation area. Non- riverine floodplain storage may be replaced at or below the existing elevation but not below the proposed normal water level. 2. MODIFICATION OF STANDARD: The City Council may make specific findings based upon the results of detailed hydrologic and hydraulic engineering analysis, and drainage, wetlands or other studies that the above standard be modified to not less than a ratio of 1.0 times the volume of floodplain storage lost or displaced. Said findings and modification of standard shall be allowed only in unique situations where a proposed planned unit development complying with this modified standard results in a net regional watershed benefit not otherwise realized by strict application of the requirements, as determined solely in the discretion of the City Council. The following criteria shall also be considered when granting a modification of this Standard: a) The modification in Standard will not increase the probability of flood damage or create an additional threat to the public health, safety, and welfare. b) The modification must be demonstrated to provide a net watershed benefit when compared to the existing condition. A net watershed benefit may be defined in one of the two following ways. 1) The modification will substantially reduce downstream peak discharges (more than 10%); or will reduce downstream flood stages (more than 0.1 foot); or will reduce damages to downstream structures. This benefit must be demonstrated through a detailed hydrologic and hydraulic analysis of the watershed on a regional scale as approved by the City Engineer. 2 2) The modification will provide significant environmental and recreational benefits. Environmental and recreational benefits considered would be the meandering of channels, the creation of wetlands or other natural areas, and the implementation throughout the development of Best Management Practices with respect to stormwater management and stormwater quality. In addition, the modification must be shown to maintain floodway conveyance and not increase downstream flows or flood stages. This must be demonstrated through a detailed hydrologic and hydraulic analysis of the watershed on a regional scale as approved by the City Engineer. c) The modification in Standard is the minimum required considering each of the following statements of policy underlying this ordinance and there are no means other than the requested modification by which the demonstrated hardship can be avoided or remedied to a degree sufficient to permit the reasonable continuation of the development. 1) Site storage of floodwater shall also contribute to the improvement of water quality. 2) High quality natural areas shall be preserved on the site, including without limitation, stands of native trees, existing wetlands, depressional storage or other valuable environmental and biological resources. d) The modification is not requested solely for the purpose of increasing density of the development or impervious areas on the site. e) If applicable, the modification is required due to unique, natural topographic features of the site. f) The applicant's circumstances are not self-imposed. g) No modification shall be granted for any development in the regulatory floodway, regulatory wetlands or critical wetlands, the effect of which would be to create regulations less restrictive than the federal or state minimum standards applicable to development in such areas. SECTION 4: SEVERABILITY The various parts, sections, and clauses of this Ordinance are hereby declared to be severable. If any part, sentence, paragraph, section, or clause is adjudged unconstitutional or invalid by a Court of competent jurisdiction, the remainder of the Ordinance shall not be affected thereby. 3 SECTION 5: REPEALER Any Ordinance or Resolution or parts thereof in conflict with the provisions of this ordinance are hereby repealed to the extent of such conflict. Paul James Marty Munns Richard Sticka � Mike Anderson Valerie Burd Rose Spears Larry Kot Joseph Besco —It Approved by me, as Mayor of the United City of Yo r ; le, Kendall County, nois this k_day of ►��,, , A.D. 2002. Mayor Passed by the City Council of the United City of Yorkville, Kendall County, Illinois this \2j,_day of j��" . , A.D. 2002. Attest: i Jerk Law Offices of Daniel J. Kramer 1107A S. Bridge Street Yorkville, Illinois 60560 4 jy -I - I I I I I I I I I I I 1 I I I I I I I I I I ExISTXC EL0.O'PLVN BOUNDARY I - PRWOSEO iL�PLRIX RWNO/RY � I I I I I I PftOPOSEDFLOWWAY EMISIINL 1I.KAIN RWNT.IRY I - I I I'I I •I I I I I I I I I I I /' ExlswD EL000wnr ExlsTUC rEOOOwnr - I \ I I I I I I I 1 I I I RaOPOSED DAY R FLE f15N . - IFWNY I I I I I I •I I I I I 1 I I• I I - I m a' EXISTING CONDITIONS COMP STORAGE ® 1.5 TO 1.0 MODIFIED STANDARD Y a M O oEXISTING FLOODWAY EXISTING FLOODWAY I�PROPOSED FLOODWAY�I S 00 YEAR FL000 ELE�1 I11 0 YEAR FLOOD ELEV. 1 I -------_--_—I--------------I------------- —r'---------_—_—I------ 1 100 YEAH FLOOD EIEV. NI I ------1---------- -------y----- B I I I I I I I I I I I L°n I I 1 I I I x I I I I N I I I I 3 I I I I I I I I I I I I I N O O } G��x=x,WSUaaOAVmxI�EnE vEES�aO� -1YRIGHT©2002 ENGINEERING ENTERPRISES, INC. 3 DATE OCTOBER 2002 �1 Engineering Enterprises,Inc. United City of Yorkville DESIGNED BY: —/--- UNITED CITY OF YORKNALLE COMPENSATORY STORAGE PROJ. NO. Y00217 0e! Consulting Engineers Kendail County, Illinois 610 TOWER LANE EXHIBIT FILE NO. Y0021701 o i g 9 DRAWN BY: KKP/--- YORKVIUE, IL 605%0 0 52 Wheeler Road 1 1 Q Sugar Grove, Illinois 60554 630/466-9350 1 NO I DATE I REVISIONS CHECKED BY: ---/--- a a J S