A.Required plans. Any development or other activity in the slope impact area requiring a permit pursuant to the Village Code and applicable regulations must be accompanied by the following plans and reports. Said plans and reports must be submitted to and approved by the Director prior to issuance of any permit or commencement of the proposed development.
1.All permit applications must identify the slope impact area, the slope transition area, the steep slope zone, the toe of the bluff, and the ordinary high water mark in the drawings.
2.All permit applications must contain a written description of the proposed means and methods of accomplishing such work (including without limitation the sequencing and timing of work, the equipment to be used, interim protective measures, and activities to monitor potential adverse impacts on the slope impact area), which means and methods will be designed to minimize slope damage. Upon approval of the permit by the Director, such approved written description will be the enforceable means and method of the authorized development activities.
3.Professional engineering. All structures within the slope impact area must be designed by a licensed structural engineer or geotechnical engineer, or both, and must bear the engineer’s license seal on submitted drawings and specifications satisfying good engineering practices and the standards of this Chapter, unless the Director otherwise waives this requirement in writing.
4.Subsoil investigation. Every application for a development permit in the slope impact area must be accompanied by a report, prepared by a licensed professional civil engineer or structural engineer, or both, trained and experienced in the practice of geotechnical engineering, which report must include the following:
a.Soil types and subsurface materials. A description (the result of a thorough subsurface investigation using techniques such as borings, test pits, site tests, laboratory tests, or other procedures performed to a depth sufficient to determine foundation conditions for the proposed construction) of the soil and subsurface materials found on the subject site (with particular emphasis on the area to be impacted by the proposed development) to a depth extending below any proposed excavation as well as the engineering properties of the subsurface soil materials.
b.Observations. A description of existing observable slide areas, scarps, tension cracks, eroded areas, leaning trees, etc.
c.History. A historical review of bluff stability considering owner photographs, previous reports and topographic surveys; air photos, U.S. Army Corps of Engineers’ studies, Village of Winnetka information, etc.
d.Drainage. A description of surface patterns of water flow and seeps as well as indication of the presence or absence of permeable zones in underlying soils.
e.Stability. A geotechnical stability analysis of the slope and structure with factors of safety calculated for the existing and proposed conditions by a method that satisfies both force and moment equilibrium for long-term and short-term soil strength parameters.
f.External influences. A description of any existing or anticipated problems from undercutting at the base of a slope impact area caused by wave action, erosion, or channel changes.
g.Absence of special hazards. An opinion that the soil types, soil stability, subsurface hydrology, and external influences affecting the site will not cause any significant hazards for the proposed use; or if they may cause such hazards, an opinion that such hazards can be overcome, together with a reasonably detailed description of how it is proposed to overcome them.
5.Grading plan. In addition to any other permit requirements, each application for a permit involving development under this Chapter must be accompanied by a grading plan, which plan will include the following:
a.A topographic survey, showing property contours at one foot intervals for table land and five foot intervals for steep slopes, including special notes and details of the existing terrain;
b.Proposed filling, grading, and earth moving details, including the dimensions, elevations, and contours of any proposed filling, grading, and earth moving;
c.A schedule of when each stage of the project will be completed, including the estimated starting and completion dates; and
d.A provision requiring the placement of a temporary fence on the table land at the top edge of steep slope zone until construction is completed.
6.Hydrological control plan. Applications for any development permits will include a plan for intercepting and containing drainage at the site and from the structure.
7.Vegetation plan. A vegetation plan, subject to the tree removal provisions of the Village Code, will be submitted with each application for a development permit, which plan will include the following:
a.A description of proposed revegetation of disturbed areas, specifying the materials to be used;
b.An inventory describing the existing vegetation and tree cover of the site showing those areas where the vegetation will be removed as part of the proposed development;
c.A maintenance and monitoring plan for native vegetation and soil erosion and sediment controls in the steep slope zone;
d.A written description detailing methods of slope stabilization and revegetation, together with the rationale for selecting the plant materials and planting techniques proposed to be used: and
e.A timetable and sequencing program for implementing the vegetative plan.
8.Additional submittals: waivers. The Director may require additional plans as needed for review. The Director may release an applicant from any element of the aforementioned plan submittals to the extent that the Director determines that such element(s) will not materially assist in the evaluation of the proposed action's impact on slope stability. Whenever the Director waives or alters otherwise applicable requirements in this Section, the waiver or alteration will be memorialized in a written decision that provides the rationale for the waiver or alteration. Before the Director finalizes the waiver or alteration, the Director will confer with the Village Manager and the Director of Community Development.
B.Permit issuance; terms. Each permit application for development must comply with the Title 15 of the Village Code, this Title, and other applicable codes, ordinances, or regulations, including this Chapter, The seal of an Illinois licensed structural or geotechnical engineer, or both, will appear on all plans and specifications included as part of a permit application. Upon the Director determining that an application satisfies the requirements of this Chapter, the Director will cause a permit to be issued for development within the slope impact area. The following provisions will be incorporated into and made a part of any such permit:
1.Limited obligation. Compliance with the procedures of this Chapter and the issuance of any related permits will not be construed to impose any legal or other obligation upon the Village of Winnetka or its elected or appointed officials, employees, agents, attorneys, or representatives. Any permit issued pursuant to this Chapter is for the benefit of the public and not for the benefit of any individual.
2.Civil claims. Compliance with the procedures of this Chapter and the issuance of related permits will not relieve the permittee and the property owner from civil liability claims.
3.Endorsem*nt. Compliance with the procedures of this Chapter and the issuance of related permits do not imply approval of the need for, or the benefit or efficacy of, the proposed development; nor does it constitute any assertion that the proposed development will not result in damage to the property in question or to adjoining property.
4.Closing report. A licensed professional structural engineer or geotechnical engineer, or both, must inspect all work in the steep slope zone while in progress and, upon completion of the work, deliver to the Director a written report bearing the engineer's license seal, stating that all development is in accordance with the approved plan and specifications for the project. Such a report must be delivered prior to the Village's final inspection, acceptance, and closing of the project.
5.Special terms. In connection with the issuance of a permit pursuant to this Chapter, the Director may impose special conditions as deemed necessary to ensure the effectiveness of plans for development on a property, and to protect the long-term stability of a bluff, or otherwise to notify future owners of the bluff conditions of such property.
C.Other Regulatory Agency Plans. The Director has the discretion to determine whether review by any other agencies will be required as part of the Director's review.
(MC-01-2024 § 2, Added, 02/06/2024)
