(A) Buffer areas required. Buffer areas shall be required along all streams, lakes, waterways, channels and wetlands, except the following:
(1) Roadside ditches;
(2) Existing excavated stormwater storage facilities;
(3) Borrow pits and quarries;
(4) Leveed waterways; and
(5) Improvement to existing public roads and utilities.
(B) Buffer area dimensions.
(1) Linear buffers. Linear buffers shall be designated along both sides of all streams and natural channels. A minimum buffer of 30 feet on each side of the channel shall be provided.
(2) Water body buffers. Water body buffers shall encompass all lakes, wetlands, and other nonlinear bodies of water. A minimum buffer of 30 feet on each side of the channel shall be provided.
(3) Exceptional functional value wetlands shall have a minimum buffer of 100 feet.
(4) In areas having state or federal threatened and endangered species present or for Illinois Natural Inventory Sites, buffer widths may be modified to meet the terms and conditions specified during consultation with the Illinois Department of Natural Resources or United States Fish and Wildlife Service, pursuant to state and federal laws and regulations.
(5) The buffer area for all Waters of the United States shall extend from the ordinary highwater mark. The buffer area for wetlands shall extend from the edge of the delineated wetland. A property may contain a buffer area that originates from the Waters of the United States on another property.
(6) Buffer-averaging may be allowed by the city engineer, provided the buffer width is at least half of the buffer width required by this chapter or the minimum width required by a Corps of Engineers permit, whichever is wider.
(C) Buffer requirements.
(1) Features of the stormwater management system may be within the buffer area of a development.
(2) Access through buffer areas shall be provided, when necessary, for maintenance purposes.
(3) Preservation of buffer areas shall be provided by deed or plat restriction.
(D) Allowed uses in buffer areas.
(1) All buffer areas shall be maintained free from development except for the following:
(a) Passive recreation, including pedestrian, bicycle or equestrian trails; and
(b) Construction and maintenance of utilities and stormwater facilities.
(2) Structures and impervious surfaces related to recreational facilities, such as trails and paths, may occupy a maximum of 20% of the buffer surface area, provided the runoff from such facilities is diverted away from the Waters of the United States or such runoff is directed to enter the buffer area as unconcentrated flow. Boat docks, boathouses, and piers shall be allowed and count as a structure when calculating percent of impervious area.
(3) Buffer areas hydrologically disturbed by allowing construction or as part of a re-vegetation plan shall be re-vegetated using the Native Plant Guide for Streams and Stormwater Facilities in Northeastern Illinois, (NRCS et al.) as a minimum standard.
(E) Channel protection.
(1) If the proposed activity involves a channel modification, the permit applicant shall demonstrate that:
(a) There are no practicable alternatives to the activity which would accomplish its purpose with less impact to the natural condition of the body of water affected. Channel modification is acceptable if the purpose is to restore natural conditions and improve water quality and fish and wildlife habitat.
(b) Water quality, habitat, and other natural functions would be significantly improved by the modification and no significant habitat area may be destroyed, or the impacts are offset by the replacement of an equivalent degree of natural resource values.
(2) A channel modification shall be designed and constructed in a way which will minimize its adverse impacts on the natural conditions of the body of water affected, consistent with the following criteria:
(a) The physical characteristics of the modified channel shall match as closely as possible those of the existing channel in length, cross-section, slope, and sinuosity. If the existing channel has been previously modified, restoration of more natural physical conditions should be incorporated into the channel modification design.
(b) Hydraulically effective transitions shall be provided at both the upstream and downstream ends of the project, designed such that they will prevent erosion.
(c) One-sided construction of a channel shall be used when feasible. Removal of stream side (riparian) vegetation should be limited to one side of the channel, where possible, to preserve the shading and stabilization effects of the vegetation.
(d) Clearing of stabilizing vegetation shall be limited to that which is essential for construction of the channel.
(e) Channel banks shall be constructed with a side slope no steeper than 3:1 (horizontal to vertical) wherever practicable. Native vegetation and gradual side slopes are the preferred methods for bank stabilization. Where high velocities or sharp bends necessitate the use of alternative stabilization measures, soil bio-engineering techniques, natural rock or rip-rap are preferred approaches. Artificial materials such as concrete, gabions, or construction rubble should be avoided unless there are no practicable alternatives.
(f) All disturbed areas associated with the modification shall be seeded or otherwise stabilized as soon as possible upon completion of construction. Erosion blanket or an equivalent material shall be required to stabilize disturbed channel banks prior to establishment of the vegetation cover.
(g) If the existing channel contains considerable bottom diversity such as deep pools, riffles, and other similar features, such features shall be provided in the new channel. Spawning and nesting areas and flow characteristics compatible with fish habitat shall also be established, where appropriate.
(h) A sediment basin shall be installed at the downstream end of the modification to reduce sedimentation and degradation of downstream water quality.
(i) New or relocated channels should be built in the dry and all items of construction, including vegetation, should be completed prior to diversion of water to the new channel.
(j) There shall be no increase in stage or velocity as the channel enters or leaves the project site for any frequency flood unless necessitated by a public flood control project or unless such an increase is justified as part of a habitat improvement or erosion control project.
(k) Unless the modification is for a public flood control project, there shall be no reduction in the volume of floodwater storage outside the floodway as a result of the modification.
(F) Dumping.
(1) No person, firm, corporation, or governmental agency shall dispose of or dump grass clippings, brush, fill, trash, debris, or other material that may obstruct the flow or storage of water in any channel, swale, culvert, storm sewer, wetland, storage basin, or other natural or man-made watercourse or water body.
(2) No person, firm, corporation, or governmental agency shall dispose of or dump any petroleum products, chemicals, noxious liquids, animal waste or other material that will pollute the water in any channel, swale, culvert, storm sewer, wetland, storage basin, or other natural or man-made watercourse or water body.
(Ord. O-14-03, passed 2-18-03)