The watershed management ordinance, commonly referred to as the WMO is hereby amended and supplemented by the following provisions which correspond to the articles as numbered in the code.
Article 1 see WMO
Article 2 see WMO
Article 3 see WMO
Add § 300.8 The co-permittee may be required by recommendation of the village engineer and in accordance with subsection 11-2-2B9 of this code, to file with the village a cash bond or irrevocable letter of credit, satisfactory to the village attorney in an amount deemed sufficient by the village engineer to cover all costs of the required improvements, landscaping, maintenance of improvements and landscaping and soil erosion and sediment control measures for such a period as specified by the village, and engineering and inspection costs to cover the cost of failure or repair of improvements installed on the site.
Replace § 314.1 with "Construction activities authorized under a watershed management permit must be initiated within 120 days following the date of the permit issuance. Failure to commence construction activities within those 120 days renders the issued watershed management permit null and void."
Replace § 314.2 with "Construction activities authorized under a watershed management permit must be completed within 180 days following the date of the permit issuance."
Replace § 314.3 with "If construction activity has been started but is not completed within 180 days of the date of issuance of a watershed management permit and the co- permittee intends to pursue the permitted activity, then the co-permittee shall submit a written request for an extension. Upon receipt of such request, either the MWRD or the village may grant an extension for the construction activities under the watershed management permit".
Article 4 see WMO
Replace § 401.6 with "Portions of the development site where construction activities have temporarily or permanently ceased, must have stabilization practices initiated within 1 working day and completed within 14 days except:
A. Where precluded by snow cover, erosion control practices shall be completed as soon as possible; or
B. Where construction activity resumes on that portion of the site within 14 days from when the activity ceased."
Article 5 see WMO
Add § 500.8 "In the selection of a drainage plan for a development, the co-permittee shall evaluate and implement, where practicable, site design features which minimize the increase in runoff volumes and rates from the site. The co- permittee's drainage plan shall adopt one or more of the following strategies in order of preference. If the strategies with the highest preference are not adopted, the drainage plan submitted shall include a rationale for not selecting those strategies with a higher preference.
A. Preservation of the natural features of development sites, including natural storage and infiltration characteristics.
B. Preservation of existing natural streams, channels and drainageways.
C. Minimization of new impervious surfaces.
D. Conveyance of stormwater in open vegetated channels.
E. Construction of best management practices (BMPs) that provide both quantity and quality control with BMPs serving multiple sites being preferable to those serving individual sites.
F. Construction of BMPs that provide only quantity control, with BMPs serving multiple sites being preferable to those serving individual sites".
Add § 501.4 "Wetlands and other depressional storage areas shall be protected from damaging modifications and adverse changes in runoff quality and quantity associated with land developments. In addition to the other requirements of this ordinance, the following requirements shall be met for developments whose drainage flows into wetlands and depressional storage areas as appropriate:
A. Existing wetlands shall not be modified for the purposes of stormwater detention unless it is demonstrated that the existing wetland is low in quality and the proposed modifications will maintain or improve its habitat and ability to perform beneficial functions. Existing storage and release rate characteristics of wetlands and other depressional storage areas shall be maintained and the volume of detention storage provided to meet requirements of this section shall be in addition to this existing storage.
B. The existing wetland shall be protected during construction by appropriate soil erosion and sediment control measures and shall not be filled.
C. Site drainage patterns shall not be altered to substantially decrease or increase the existing area tributary to the wetland.
D. A buffer strip of at least twenty-five feet (25') in width, preferably vegetated with native plant species, shall be maintained or restored around the periphery of the wetland."
Replace § 502.12 with "Maximum flow depths on roads for all development shall not exceed curb heights by more than one (1) inch during the base flood condition and shall not remain flooded for more than eight (8) hours during the base flood condition."
Replace § 502.13 with "Maximum detention depths on new parking lots shall be designed for protection against damages caused by stormwater detention inundation, which shall not exceed six (6) inches for more than four (4) hours. The inundation hazard below the 100-year high water elevation shall be clearly posted."
Add § 503.4 "Infiltration practices including basins, trenches, and porous pavement should be located on soils in hydrologic groups "A" or "B" as designated by the U.S. soil conservation service. Infiltration basins and trenches designed to recharge groundwater shall not be located within seventy five feet (75') of a water supply well or a building foundation. A sediment settling basin may be required to remove coarse sediment from stormwater flows before they reach infiltration basins or trenches. Stormwater shall not be allowed to stand more than seventy two (72) hours over eighty percent (80%) of a dry basin's bottom area for the maximum design event to be ex-filtrated. The bottom of infiltration facilities shall be a minimum of four feet (4') above the seasonal high water table and bedrock unless otherwise approved by the enforcement officer"
Replace § 504.3.A with "0.15 cfs/acre of development for the storm event having a one percent probability of being equaled or exceeded in a given year (100-year storm event)."
Replace § 504.3.B with "0.04 cfs/acre of development for the storm event having a fifty percent probability of being equaled or exceeded in a given year (2-year storm event)."
Add § 504.11.H "Wet detention basins shall be designed so to remove stormwater pollutants, to be safe, to be aesthetically pleasing, and, as much as feasible, to be available for recreational use. Wet basins shall be at least three feet (3') deep, excluding near shores, banks and safety ledges. If this habitat is to be provided, it shall be at least ten feet (10') deep over twenty-five percent (25%) of the bottom area to prevent winter freeze-out. The side slopes at the normal pool elevation shall not be steeper than five to one (5:1) horizontal to vertical. The permanent pool volume at normal depth shall be equal to the runoff volume from its watershed for a 2-year event. To the extent possible, the distance between detention inlets and outlets shall be maximized and, if possible, should be at opposite ends of the basin."
Add § 504.11.I "The use of dry basins within the village is prohibited unless the village engineer finds and the village board concurs that other detention methods are inappropriate or ineffective. When so determined, such dry basins shall be, in addition to the other requirements of this ordinance, designed to remove stormwater pollutants, to be safe, to be aesthetically pleasing and, as much as feasible, to be available for multiple uses. All detention basin areas shall be designed to have standing water no longer than seventy two (72) hours for any runoff event less than the 100-year event. Underdrains directed to the outlet may be used to accomplish this requirement. Velocity dissipation measures shall be incorporated into dry basin designs to minimize erosion at inlets and outlets and to minimize the occurrence of suspended solids. Stilling/sedimentation basins should be constructed at each major inlet. The volume of the basins should be at least 500 cubic feet per acre of impervious surface in the drainage area. Side slopes of the basins shall be no steeper than three to one (3:1) (horizontal to vertical) and basin depths should be at least three feet (3') to minimize the suspension of accumulated sediment. To the extent possible, the distance between detention inlets and outlets shall be maximized and, if possible, should be at opposite ends of the basin. There should be no low flow bypass between the inlet and the outlet. Paved low flow channels shall not be used."
Add § 504.11.J "Detention basins shall be designed to protect the safety of any children or adults coming in contact with the system during runoff events. The following design criteria in the design of these basins:
1. The side slopes of all detention basins at the 100 year capacity shall be level as practicable to prevent accidental falls into the basin and for stability and ease of maintenance and shall be no steeper than three to one (3:1) (horizontal to vertical).
2. All wet detention basins shall have a safety ledge at least four feet (4') in width located two and one- half feet (2.5') to three feet (3.0') below the normal water depth.
3. Velocities throughout the surface drainage system shall be controlled to safe levels taking into consideration rates and depths of flow."
Add § 504.11.K "The stormwater drainage system shall be designed to minimize and facilitate maintenance. Vegetated side slopes shall be designed to allow lawn mowing equipment to easily negotiate them. Wet basins shall be provided with alternate outflows which can be used to completely drain the pool for sediment removal. Pumping may be considered if drainage by gravity is not feasible. Sedimentation basins shall be included where feasible for localizing sediment deposition and removal. Access for heavy equipment shall be provided."
Replace § 504.12.E with "4 inches or larger in diameter and designed to be self-cleaning and"
Article 6 see WMO
Replace § 602.9.A with "Equal to at least 1.5 times the volume of flood storage lost below the BFE."
Replace § 603.9.A and B with "Fifty feet from the boundary of standard isolated wetlands greater than or equal to one- half (0.50) of an acre in area."
Add § 604.20 "The following development activities may be permitted within buffer areas only if, as a practical matter, they cannot be located outside the buffer area. Such development activities will only be approved based upon a report prepared by a qualified professional which demonstrates that they will not adversely affect water quality; destroy, damage or disrupt significant habitat areas; adversely affect drainage and stormwater retention capabilities; adversely affect flood conveyance and storage; lead to unstable earth conditions, create erosion hazards, or be materially detrimental to any other property in the area of the subject property or to the village as a whole, including the loss of open space or scenic vistas:
A. Minor improvements such as walkways, benches, comfort stations, information displays, directional signs, foot bridges, observation decks and docks;
B. The maintenance, repair, replacement and reconstruction of existing highways and bridges, electrical transmission and telecommunication lines, poles and towers;
C. The establishment and development of public and private parks and recreational areas, outdoor education areas, historical natural and scientific areas, game refuges, fish and wildlife improvement projects, game bird and animal farms, wildlife preserves and boat launching ramps;
D. Limited filling and excavating necessary for the development of boat launching ramps, swimming beaches, or the development of park shelters or similar structures is allowed;
E. Limited development of roads, parking lots and other impervious surfaces necessary for permitted uses where no alternate location outside the buffer area is available;
F. Stormwater drainage swales between the developed area of the site (including a stormwater detention facility on the site) and a stream, lake or pond, or wetland. Detention basins within the buffer are generally discouraged unless it can be shown that resultant modifications will not impair water quality, habitat or flood storage functions;
G. Installation of piers for the limited development of walkways and observation decks. Walkways and observation decks should avoid high quality wetland areas and should not adversely affect natural areas designated in the Illinois natural areas inventory or the habitat of rare or endangered species."
Add § 607.12 "Watercourse relocation or modification is not permitted as a convenience for site design purposes. Under certain circumstances, relocation and minor modification may be permitted where certain problems can be mitigated by relocation and/or minor modification, specifically when:
A. Off-site hydrologic conditions are causing erosion, flooding and related problems; or
B. On-site soil and geologic conditions are resulting in unstable conditions that pose hazards to life, health and existing structures or property; or
C. The quality of previously modified or relocated streams can be improved through restoration; or
D. Officially adopted stormwater management plans call for placement of detention or retention facilities in a stream; or
E. Public utilities, including sanitary sewers, pipelines and roadways require stream crossing or relocation where there are not practical alternatives."
Add § 607.13 "Stream modification, when permitted, is subject to the following conditions and restrictions:
A. Water quality, habitat and other natural functions must be significantly improved by the modification; no significant habitat area may be destroyed;
B. The amount of flow and velocity of a stream is not to be increased or decreased as the stream enters or leaves a subject property, unless this reflects an improvement over previous conditions in terms of reduced flooding, reduced erosion, or enhanced low-flow conditions.
C. Stream channel enlargement or other modifications that would increase conveyance, shall not be permitted if the intended purpose is to accommodate development activities in the floodplain."
Add § 607.14 "Armoring in the form of bulkheads, riprap or other materials or devices is not permitted except in accordance with the following:
A. Significant erosion cannot be prevented in any other way and the use of vegetation and gradual bank slopes has not sufficiently stabilized the shoreline or bank;
B. The bulkhead or other device is not placed within a wetland or between a wetland and a lake or pond;
C. The bulkhead, riprap or other device will minimize the transmittal of wave energy or currents to other properties; and
D. The change in the horizontal or vertical configuration of the land must be kept to a minimum."
Add § 607.15 "Culverts are not permitted in streams except in accordance with the following:
A. Where a culvert is necessary for creating access to a property. Use of culverts as a convenience in order to facilitate general site design shall not be permitted;
B. The culvert must allow passage of fish inhabiting the stream and accommodate the 100 year flood event without increasing upstream flooding except where a restricting culvert is desirable as part of an overall storm and floodwater management plan;
C. The culvert must be maintained free of debris and sediment to allow free passage of water and fish."
Add § 601.16 "Impoundments of streams is not permitted except in accordance with the following:
A. The impoundment is determined to be in the public interest by providing regional stormwater detention, flood control or public recreation;
B. The impoundment will not prevent the upstream migration of indigenous fish species;
C. A nonpoint source control plan has been implemented in the upstream watershed to control the effects of sediment runoff as well as minimize the input of nutrients, oil and grease, metals and other pollutants;
D. Impoundments without permanent low-flow pools are preferred except where a permanent pool is necessary to achieve the intended benefits of the impoundment (e.g. recreation or water quality mitigation); and
E. Impoundment design shall include gradual bank slopes, appropriate bank stabilization measures, and sedimentation basins."
Article 7 see WMO
Article 8 see WMO
Article 9 see WMO
Article 10 see WMO
Replace § 1000.4 with "Inspections shall verify compliance with this ordinance and issued watershed management permits. The co-permittee shall notify the village engineer within two (2) working days of the completion of the construction stages specified below:
A. After mobilization and installation of initial erosion and sediment control measures prior to any soil disturbance;
B. After rough grading;
C. During excavation for the construction of qualified sewer construction, major stormwater systems and detention facilities;
D. After final grading, seeding and landscaping;
E. Completion of qualified sewer construction; and
F. Other stages as specified by the village engineer or the village designated enforcement officer; and
G. If stripping, clearing grading and/or landscaping are to be done in phases, the co-permittee shall give notice and request inspection at the completion of the above work stages in each phase."
Add § 1000.6 "The co-permittee or his/her agent shall make regular inspections of all control measures in accordance with the inspection schedule outlined on the approved erosion and sediment control plans. The inspector shall be a person knowledgeable in the principles and practices of erosion and sediment control measures and the inspections shall be performed at least once every seven (7) calendar days and within twenty-four (24) hours of the end of a storm that produces a rainfall depth of one-half (0.5) inch or greater. The purpose of such inspections will be to determine the overall effectiveness of the control plan and the need for additional control measures. All inspections shall be documented in written form and submitted to the village engineer at the time interval specified in the approved permit."
Article 11 see WMO
Article 12 see WMO
Article 13 see WMO
Article 14 see WMO
Signature page see WMO
Appendix A see WMO
Appendix B see WMO
Appendix C see WMO
Appendix D see WMO
Appendix E see WMO
Appendix F see WMO
Appendix G see WMO
(Ord. 0-2015-1062, 3-19-2015)