(A) Review of application. Any application for development in the Steep Slope Zone shall be reviewed by the code official, who will consider such application in light of the standards of this section relating to landscape planning, soil mechanics engineering, hydrology, geology, environmental design, and architecture. It is recognized, however, that each Steep Slope Zone has unique characteristics and encounters different dynamics affecting its stability and preservation. As a result, the code official may determine for any application that certain of the following standards may not apply in whole or in part to such application so long as the code official determines that the application for development in its totality satisfies the purposes of this chapter.
(B) Standards. The standards applicable to development in a Steep Slope Zone are as follows:
(1) Filling, grading, and earth moving.
(a) Minimum alterations. Filling, grading, and earth moving shall be limited to the minimum required for removal and replacement of foundations, driveways, drainage control structures, and immediate yard areas. Substantial filling, grading, and earth moving shall not be permitted and is prohibited.
(b) Erosion control. All filling, grading, and earth moving shall be accomplished in a manner that will create the lowest possible potential for airborne or waterborne transportation of soil. Temporary erosion control matting shall be properly staked and trenched nightly where large areas of soil are exposed.
(c) Soil fill in Steep Slope Zone. All fill in the Steep Slope Zone is prohibited, other than back-fill which is determined by the code official to be necessary for slope stabilization.
(d) Soil fill on table land. In conformance with generally accepted engineering standards, all fill on table land shall be stabilized to at least 90% of maximum dry density as determined in ASTM procedure D-1557 or equivalent.
(e) Prompt completion. Any earth moving shall be accomplished in the shortest practical period of time, the schedule of which shall be approved by the code official. All excavated material shall be removed from the Steep Slope Zone and no temporary or permanent material storage shall be permitted within the Steep Slope Zone. No existing natural vegetation shall be destroyed, removed or disturbed prior to the initiation of development activities.
(2) Safety control of steep slopes.
(a) The development will not jeopardize slope stability on the subject site or neighboring properties.
(b) Except as can be shown to be essential or beneficial for an approved development, no filling, grading, and earth moving shall occur in a Steep Slope Zone.
(c) Whenever there is construction upon any property that includes or is adjacent to a Steep Slope Zone, a fence will be erected temporarily along the top edge of the Steep Slope Zone, during any construction and/or demolition activity upon such property.
(3) Construction techniques. All proposed structures shall have foundations designed in a manner consistent with sound engineering and geological principles. In addition, the following techniques shall be employed to enhance stabilization of the ravine or bluff:
(a) Planning the development to recognize and fit the natural topography, soils, geology, hydrology, and other existing conditions on the proposed sites;
(b) Orienting development so that filling, grading, and earth moving, landscaping and other site preparation is kept to an absolute minimum;
(c) Preserving the landscape through minimized disruption of natural terrain and existing vegetation;
(d) Minimizing disruption or alteration of natural drainage ways;
(e) Minimizing the time during which areas are bare and exposed;
(f) Designing and properly locating structures so that structure’s weight does not negatively impact slope stability; and
(g) Considering the effect of undercutting at the base of a Steep Slope Zone caused by wave action, storm water flow, erosion, and/or channel changes.
(h) Providing for management of silt runoff during the construction period.
(4) Vegetation and revegetation.
(a) Natural vegetation. Unless being revegetated as part of the development, every effort shall be made to maintain natural vegetation in the Steep Slope Zone.
(b) Smallest area. At all times, the smallest practical area of raw soil shall be exposed for as short a duration of time as practical. When required by the code official pursuant to sound professional engineering principles, temporary vegetation or other acceptable cover shall be used to protect areas of raw soil exposed during development and to prevent airborne or waterborne transportation of soil.
(c) Revegetation. A mixed planting of perennial and woody species is recommended for use in the Steep Slope Zone disturbed by development.
(d) Erosion control mat. Temporary erosion control matting properly staked and trenched shall be provided over raw soil areas until new vegetation is established.
(5) Hydrological controls.
(a) Natural channels. Natural drainage ways shall be preserved to the maximum extent possible.
(b) Controlled runoff. Concentrated runoff from impervious surfaces shall be collected and transported in a pipe or other approved manner to a municipal storm sewer system, if available. In no instance shall runoff be transported to, directed toward, or be allowed to collect in any pipe or conveyance that is part of the combined storm/sanitary sewer system of the village.
(c) Water discharge into steep slope. Whenever stormwater is transported across a property for discharge into a Sleep Slope Zone, the conveyance pipes shall be of non-segmented (continuous sections of minimum 100 feet) pipe material, which shall be installed below ground by directional boring where possible.
(d) Trenching. No pipe shall be installed within a Steep Slope Zone by excavating a trench unless such trench is approved by the code official.
(e) Pipe materials. Flexible corrugated pipes shall not be used within a Steep Slope Zone unless directional boring is found to be infeasible in the sole determination of the code official.
(f) Interceptor ditches. When required by the code official pursuant to sound professional engineering principles, interceptor ditches shall be established above steep slopes in order that soil shall not become saturated and the intercepted water shall be conveyed in a pipe or other approved manner to a municipal storm sewer system, if available, or to the bottom of ravine or bluff slopes in a manner designed to prevent erosion. In no instance shall runoff be transported to, directed toward, or be allowed to collect in any pipe or conveyance that is part of the combined storm/sanitary sewer system of the village.
(g) Discharge point stabilization. Natural drainage ways shall be stabilized by landscape integration and rip-rap or other means consistent with sound professional engineering practice, to a distance below drainage and culvert discharge points sufficient to convey the discharge without channel erosion and in such a manner as to dissipate the energy of the discharge as approved by the code official.
(h) Energy dissipater. All outflow from a stormwater conveyance pipe must discharge into an energy dissipater designed to slow fast moving stormwater and prevent soil erosion.
(i) Early completion. The overall drainage system shall be completed and made operational at the earliest possible time during construction, the schedule of which shall be approved by the code official.
(j) Impact on adjacent property. The natural or usual flow of surface or subsurface water shall not be altered or obstructed in any way by grade changes that may adversely affect the property of another by contributing either to pooling or collection of waters or to the concentration or intensification of surface water discharge.
(Ord. 1163, passed 12-14-2015)