(A) Appearance and preservation. In order to preserve, enhance and promote the existing and future appearance and resources of hillsides for the maximum retention of natural topographic features and qualities, the Council shall encourage the maximum retention of the following:
(1) Skyline and ridge tops;
(2) Rolling grassy landforms, including knolls, ridges and meadows;
(3) Tree and shrub masses, grass, wildflowers and topsoil;
(4) Rock outcropping;
(5) Stream beds, draws and drainage swales, especially where tree and plant formations occur; and
(6) Characteristic vistas and scenic panoramas.
(B) Hillside development evaluation. All development proposals shall take into account and shall be judged by the application of current understanding of land use planning, soil mechanics, engineering geology, hydrology, civil engineering, environmental and civic design architecture and landscape architecture in hill areas. Such current understanding includes, but is not limited to:
(1) Planning and development to fit the topography, soils, geology, hydrology and other conditions existing on the proposed site;
(2) Orienting development to the site so that grading and other site preparation is kept to an absolute minimum;
(3) Shaping of essential grading to complement the natural landforms and prohibiting all successive padding and/or terracing of building sites;
(4) Developing large tracts in workable units on which construction can be completed within one construction season so that large areas are not left bare and exposed during the winter-spring runoff period;
(5) Accomplishing all paving as rapidly as possible after grading;
(6) Allocation to open space and recreation uses for those areas not well suited to development, as evidenced by competent soils geology and hydrology investigations and reports;
(7) Landscaping of areas around structures to blend with the natural landscape;
(8) Placement, grouping and shaping of human-made structures to complement one another and the natural landscape, providing visual interest and creating a sense of place within the development;
(9) Demonstrating a concern for the view of the hills as well as the view from the hills;
(10) Use of a variety of housing types in residential areas, rather than exclusive use of single-family detached dwellings, to permit steep slopes, wooded areas and areas of special scenic beauty to be preserved as scenic easements, through the use of density transfers; such alternatives may include attached dwellings, apartments and condominiums, residential clusters and groups of various housing types;
(11) Special consideration in the design of such visual elements as street lighting, fences, sidewalks, pathways and other street furniture to enable maximum identity and uniqueness of character to be built into each development; and
(12) Minimizing disruption of existing plant and animal life.
(C) Engineering plans. The developer shall retain a professional engineer to obtain the following information.
(1) Soils report.
(a) Any area proposed for development shall be investigated to determine the soil characteristics, and a soils engineering report shall be submitted with every application for approval of a preliminary plat. This report shall include data regarding the nature, distribution and strength of existing soils, conclusions and recommendations for grading procedures, design criteria for corrective measures and opinions and recommendations covering the adequacy of sites to be developed.
(b) Any area in which the investigation indicates soil hazards shall not be subjected to development unless through design the engineer can demonstrate conclusively to the Commission that these limitations can be overcome in such a manner as to prevent hazard to life, hazard to property, adverse effects on the safety, use or stability of a public way or drainage channel and adverse impact on the natural environment.
(2) Geology report.
(a) Any area proposed for development shall be investigated to determine its geological characteristics and a geology report shall be submitted with every application for a preliminary plat. This report shall include an adequate description, as defined by the Commission, of the geology of the site, conclusions and recommendations regarding the effect of geologic conditions on the proposed development and opinions and recommendations covering the adequacy of sites to be developed.
(b) The investigation and subsequent report shall be completed by a professional geologist registered in the state and experienced and knowledgeable in the practice of engineering geology and presented to the Commission by either the geologist or the applicant’s engineer.
(c) Any area in which the investigation indicates geological hazards shall not be subjected to development unless through design the geologist can demonstrate conclusively to the Commission that these hazards can be overcome in such a manner as to prevent hazard to life or limb, hazard to property, adverse effects on the safety, use or stability of a public way or drainage channel and adverse impact on the natural environment.
(3) Hydrology report.
(a) Any area proposed for development shall be investigated to determine its hydrological characteristics, and a hydrology report shall be submitted with every application for approval of a preliminary plat. This report shall include an adequate description, as defined by the Commission, of the hydrology of the site, conclusions and recommendations regarding the effect of hydrologic conditions on the proposed development and opinions and recommendations covering the adequacy of sites to be developed.
(b) The investigation and subsequent report shall be completed and presented to the Commission by a qualified engineer who is experienced and knowledgeable in the sciences of hydrology and in the techniques of hydrologic investigation.
(c) Any area in which the investigation indicates hydrological hazards shall not be subjected to development unless the developer can demonstrate conclusively to the Commission that these hazards can be overcome through design in such a manner as to prevent hazard to life or limb, hazard to property, adverse effects on the safety, use or stability of a public way or drainage channel and adverse impact on the natural environment.
(d) Flood frequency curves shall be provided for the area proposed for development.
(D) Grading plan.
(1) A preliminary grading plan shall be submitted with each preliminary plat proposal and shall include the following information:
(a) Details of terrain and area drainage;
(b) Location of any existing buildings or structures on the property where the work is to be performed, the location of any existing buildings or structures on the land of adjacent owners which are within 100 feet of the property, or which may be affected by the proposed grading operations, and proposed or approximate locations of structures relative to adjoining topography;
(c) The direction of drainage flow and the approximate grade of all streets, not to be construed as a requirement for final street design;
(d) Approximate limiting dimensions, elevations or finish contours to be achieved by the grading, including all cut and fill slopes, proposed drainage channels and related construction; and
(e) Preliminary plans and approximate locations of all surface and subsurface drainage devices, wells, dams, sediment basins, storage reservoirs and other protective devices to be constructed with, or as a part of, the proposed work, together with a map showing drainage area, the complete drainage network, including outfall lines and natural drainageways which may be affected by the proposed development and the estimated runoff of the area served by the drains.
(2) A final grading plan shall be submitted with each final plat and shall include the following information:
(a) Limiting dimensions, elevations or finish contours to be achieved by the grading, including all proposed cut and fill slopes, and proposed drainage channels and related construction;
(b) Detailed plans and locations of all surface and subsurface drainage devices, walls, dams, sediment basins, storage reservoirs and other protective devices to be constructed with, or as a part of, the proposed work, together with a map showing drainage area, the complete drainage network and natural drainageways which may be affected by the proposed development and the estimated runoff of the area served by the drains;
(c) A description of methods to be employed disposing of soil and other material that is removed from the grading site, including the location of the disposal site; and
(d) A schedule showing when each stage of the project will be completed, including the total area of soil surface which is to be distributed during each stage, estimated starting and completion dates, hours of operation and days of week of operation; the schedule shall be drawn up to limit to the shortest possible period the time that soil is exposed and unprotected. In no event shall the existing (natural) vegetative groundcover be destroyed, removed or disturbed more than 15 days prior to grading.
(E) Development standards.
(1) Soils.
(a) Fill areas shall be prepared by removing organic material, such as vegetation and rubbish, and any other material which is determined by the soils engineer to be detrimental to proper compaction or otherwise not conducive to stability; no rock or similar irreducible material with a maximum dimension greater than eight inches shall be used as fill material. Materials larger than eight inches may be selectively placed within the project limits.
(b) Fills shall be compacted to at least 95% of maximum density, as determined by AASHO T99.
(c) Cut slopes shall be not steeper than two horizontal to one vertical; subsurface drainage shall be provided as necessary for stability.
(d) Fill slopes shall be not steeper than two horizontal to one vertical; fill slopes shall not be located on natural slopes 2:1 or steeper or where fill slope toes out within 12 feet horizontally of the top of an existing or planned cut slope.
(e) Tops and toes of cut and fill slopes shall be set back from property boundaries a distance of three feet plus one-fifth of the height of the cut or fill, but need not exceed a horizontal distance of ten feet; tops and toes of cut and fill slopes shall be set back from structures a distance of six feet plus one-fifth the height of the cut or fill, but not to exceed ten feet.
(2) Roadways.
(a) Roads shall be designed to create the minimum feasible amounts of land coverage and the minimum feasible disturbance to the soil.
(b) Existing vegetation of the deep-rooted perennial variety shall be preserved to the greatest extent possible in the location of roads. Road alignment should follow natural terrain, and no unnecessary cuts or fills shall be allowed in order to create additional lots or building sites.
(c) Variations in rights-of-way standards shall be permitted to prevent the dedication of unnecessarily large parcels of land.
(d) Variations in road design and road construction shall be permitted in order to keep grading and cut/fill slopes to a minimum.
(e) One-way streets shall be permitted and encouraged where appropriate for the terrain and where public safety would not be jeopardized. Maximum width shall be 17 feet between the backs of curbs.
(f) The widths of the graded section shall extend three feet beyond the curb back or edge of pavement on both the cut and fill sides of the roadway. If sidewalk is to be installed parallel to the roadway, the graded section shall be increased by the width of the sidewalk plus one foot beyond the curb back.
(g) Standard vertical curb (six inches) and gutter shall be installed along both sides of all paved roadways.
(h) A pedestrian way plan shall be required in all developments. The location and design shall require the approval of the Commission.
(3) Driveway and parking.
(a) Combinations of collective private driveways, cluster parking areas and on-street parallel parking bays shall be used to attempt to optimize the objectives of minimum soil disturbance, minimum impervious cover, excellence of design and aesthetic sensitivity.
(b) Collective private driveways shall be encouraged where their use will result in better building sites and lesser amounts of land coverage than would result if a public road were required.
(c) Cluster parking areas shall be encouraged where they will not result in drastic increases in the amount of impervious cover and/or where they might eliminate private individual parking.
(d) On-street parallel parking bays shall be encouraged where considerations of terrain or aesthetic quality would reduce the desirability of collective driveways or cluster parking.
(e) In no case shall the total number of parking spaces exceed three spaces per dwelling unit.
(F) Vegetation and revegetation.
(1) (a) The developer shall submit a slope stabilization and revegetation plan which shall include a complete description of the existing vegetation, the vegetation to be removed and the method of disposal, the vegetation to be planted and slope stabilization measures to be installed.
(b) The plan shall include an analysis of the environmental effects of such operations, including the effects on slope stability, soil erosion, water quality and fish and wildlife.
(2) The revegetation and slope stabilization plan shall be submitted with the grading plan.
(3) Vegetation shall be removed only when absolutely necessary, e.g., buildings, filled areas or roads.
(4) Every effort shall be made to conserve topsoil which is removed during construction for later use on areas requiring revegetation or landscaping, e.g., cut and fill slopes.
(5) Vegetation sufficient to stabilize the soil shall be established on all disturbed areas as each stage of grading is completed. Areas not contained within lot boundaries shall be protected with adapted, fire-resistant species of perennial vegetal cover after all construction is completed.
(6) New plantings shall be protected with organic cover.
(7) All disturbed soil surfaces shall be covered prior to December 1. If the planned impervious surfaces (e.g., roads, driveways and the like) cannot be established prior to December 1, a temporary cover adequate to prevent erosion shall be installed on those surfaces.
(8) Construction shall be scheduled to minimize soil disturbance between December 1 and April 15.
(9) The developer shall be fully responsible for any destruction of native vegetation proposed for retention. He or she shall carry the responsibility for both his or her own employees and for all subcontractors from the first day of construction until the notice of completion is filed. The developer shall be responsible for replacing such destroyed vegetation.
(10) The use of qualified personnel experienced and knowledgeable in the practice of revegetation shall be required.
(G) Maintenance. The owner of any private property on which grading or other work has been done, formed pursuant to a grading plan approved, or a building permit granted, under the provisions of this subchapter, shall continuously maintain and repair all graded surfaces and erosion prevention devices, retaining walls, drainage structures or means and protective devices, plantings and groundcover installed or completed.
(H) Utilities. All new service utilities, both on-site and off-site, shall be placed underground.
(I) Objects of antiquity.
(1) No grading, filling, clearing of vegetation, operation of equipment or disturbance of the soil shall take place in areas where any historic or prehistoric ruins or monuments, objects of antiquity or geological landmarks or monuments are present. The grading plan shall indicate the measures that will be taken to protect such areas. The State Historical Society shall approve the proposed protection measures before the grading plan is approved.
(2) Whenever during excavation there are uncovered or become apparent any historic or prehistoric ruins or monuments, or objects of antiquity, or geological landmarks, or monuments not previously accounted for in the grading plan, all work in the immediate area shall cease until the State Historical Society shall determine what precautions should be taken to preserve the historic artifacts.
(Prior Code, § 16.24.020) (Ord. 462, passed 6-9-1975) Penalty, see § 152.999