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It is intended that the development standards and provisions, as set forth herein, shall be required in connection with all building and construction in the Ogden City sensitive area overlay zone.
A. Drainage And Erosion: The area of the watershed shall be used to determine the amount of stormwater runoff generated before and after construction.
1. The "rational method" or other method as approved by the city engineer shall be used in computing runoff. The basic formula for the "rational method" is:
Q = CIA in which
Q = Runoff in cubic feet per second (CFS)
C = Coefficient of runoff or the portion of stormwater that runs off a given area (the actual C value used shall be approved by the city engineer)
I = Average rainfall intensity during time of concentration for ten (10) year return period in inches per hour. The "time of concentration" shall be defined as the time required for water to flow from the most remote point of the section under consideration
A = Drainage area in acres
2. Lots shall be arranged so as to ensure adequate setbacks from drainage channels. The 100-year storm shall be that basis for calculating setbacks. No structures shall be allowed in the 100-year floodplain.
3. Facilities for the collection of stormwater runoff shall be required to be constructed on development sites and according to the following requirements:
a. Such facilities shall be the first improvement or facilities constructed on the development site;
b. Such facilities shall be designed so as to detain safely and adequately the maximum expected stormwater runoff for a 10-year storm of two (2) hour duration, and to release it at a controlled rate equal to the runoff rate generated by the site in its natural condition. Said natural runoff rate shall not exceed 0.2 cubic feet per second per acre. The facilities shall be designed to detain runoff for a sufficient length of time so as to prevent flooding and erosion during storm runoff flow periods;
c. Such facilities shall be so designed as to divert surface water away from cut faces and sloping surfaces of a fill;
d. The existing natural drainage system will be utilized, as much as possible, in its unimproved state;
e. Where drainage channels are required, wide shallow swales lined with appropriate vegetation shall be used instead of cutting narrow, deep drainage ditches;
f. Flow retarding devices, such as detention ponds and recharge berms, shall be used where practical to minimize increases in runoff volume and peak flow rate due to development. Areas which have shallow or perched groundwater or areas that are unstable must be given additional consideration. Each facility shall have an emergency overflow system to safely carry any overflow water to an acceptable disposal point.
4. Construction of the development site shall be of a nature that will minimize the disturbance of vegetation cover, especially between October 1 and April 15 of the following year.
5. Erosion control measures on the development site shall be required to minimize the solids in runoff from such areas. The detailed design system to control stormwater erosion during and after construction shall be contained in the grading and drainage report described in section 15-27-8, "Appendix A", of this chapter.
B. Vegetation And Revegetation:
1. All areas on development sites cleared of natural vegetation in the course of construction of off site improvements shall be replanted with revegetation which has good erosion control characteristics.
2. New planting shall be protected with mulch material and fertilized when in conjunction with the planting and watering schedule in subsection B5 of this section.
3. The use of persons or firms having expertise in the practice of revegetation (i.e., licensed landscape architects or nurserymen) shall supervise the planting and installation of revegetative cover.
4. Vegetation shall be removed only when absolutely necessary, e.g., for the construction of buildings, roads and filled areas.
5. After the completion of off site improvements, vegetation will be planted in all disturbed areas only during the following time periods:
a. March 15 through May 15; and
b. September 15 through October 31.
c. If irrigated, planting may be done during summer months.
d. Such vegetation shall be a mixture of plant materials, i.e., trees, shrubs, grass and forbs. Native plant materials will be preferred.
6. No vegetation shall be removed on slopes over thirty percent (30%) except as approved by the planning commission for trail and/or open space improvements.
7. Topsoil removed during construction shall be conserved for later use on areas requiring vegetation or landscaping, i.e., cut and fill slopes.
8. All disturbed soil surfaces shall be established or covered prior to November 1. If the planned impervious surfaces (i.e., road, driveways, etc.) cannot be established prior to November 1, a temporary treatment adequate to prevent erosion shall be installed on those surfaces.
9. The property owner and/or developer shall be fully responsible for any destruction of native or applied vegetation identified as necessary for retention and shall be responsible for such destroyed vegetation. They shall carry the responsibility both for employees and subcontractors from the first day of construction until the completion of off site improvements. The property owner and developer shall replace all destroyed vegetation with varieties of vegetation approved by the planning commission. The property owner shall assume responsibility upon purchase of the lot.
C. Fire Protection:
1. Areas without a recognized water supply shall meet special requirements, on an individual basis, as established by the fire department, water utility and engineering department.
2. Each development site and building permit for private lots, flag lots, and lots where the front setback is greater than fifty feet (50'), shall be reviewed by the fire department to see that it complies with requirements for fire apparatus.
3. Spark arresters shall be installed in every fireplace constructed indoor or outdoor. Screen openings in such arresters shall not be in excess of one-fourth inch (1/4") in diameter.
D. Geology:
1. Any development within a band one-eighth (1/8) of a mile on either side of a mapped fault trace must submit a geologic report as part of the development review process.
2. Development of all structures used for human occupancy shall take place fifty feet (50') or farther from any active earthquake fault trace. Active fault traces are those identified and mapped by the city or those identified by special studies required of the developer.
3. Development of all structures used for critical facilities shall take place one hundred fifty feet (150') or farther from any active earthquake fault trace. Critical facilities shall include dams, reservoirs, fuel storage facilities, power plants, nuclear reactors, police and fire stations, schools, hospitals, nursing homes, and emergency communication facilities.
4. No structures shall be built on any zones of deformation with respect to active faults. Off site improvement design will be approved by the planning commission, upon recommendation of the city engineer.
5. No structures or off site improvements shall be allowed on any active landslide area.
6. Problems associated with development on or near perched groundwater and shallow groundwater must be mitigated in a manner as approved by the planning commission.
7. No structures shall be allowed in any high hazard rockfall zone unless mitigation measures are taken to the satisfaction of the planning commission.
E. Grading, Cuts And Fill:
1. Exposed unstable surfaces of an excavation or fill shall not be steeper than one vertical to two horizontal (1:2).
2. All permanent fill shall be located so that settlements, slidings, or erosions shall not damage or cover streets, curb, gutter, sidewalks or buildings.
3. All fill and degrees of compaction shall comply with the standards of the building code, as adopted by title 16, chapter 2 of this code, or its successor provisions.
4. The top and bottom edges of slopes caused by an excavation or fill up to ten (10) vertical feet shall be three (3) horizontal feet from the property line or public right of way lines.
5. The maximum vertical height of all cuts or fills shall be ten feet (10'). Fills for slumps or other natural depressions may exceed ten feet (10') if approved by the planning commission.
6. All structures, except retaining walls or soil stabilization improvements, shall have a setback from the crest of the fill or base of the cut of a minimum distance equal to in depth of the fill or the height of the cut, unless a structurally sound retaining wall is built for the cut or fill slope. Retaining walls may be a part of the dwelling unit.
F. Streets And Ways: Streets, roadways and private accessways shall follow as nearly as possible the natural terrain. The following additional standards shall apply:
1. At least two (2) ingress and egress routes shall be provided for each subdivision or PRUD unless the number of units served is less than twenty (20) and if the likelihood of street blockages is deemed by the planning commission to be an acceptably low risk.
2. Points of access shall be provided to all developed and nondeveloped areas for emergency and firefighting equipment. Driveways located upon each lot extending from a public or private street shall have a maximum grade of ten percent (10%) and shall be of a sufficient width and design to admit and accommodate firefighting equipment.
3. Cul-de-sacs shall not exceed six hundred feet (600') in length, unless "Dead-End" signs are posted at the entrance, and shall have a fifty foot (50') radius right of way and a forty foot (40') radius improved turnaround. Stub streets that are longer than three hundred feet (300') shall have a temporary turnaround at the end thereof.
4. Centerline curvatures shall be reviewed by the city engineer for such things as design speeds, sight distances and stopping distances.
5. Variations of the street design standards developed to solve special hillside visual and functional problems may be presented to the planning commission for consideration and approval. Examples of such variations may be the use of split roadways to avoid deep cuts, one-way streets, modifications of surface drainage treatments or sidewalk design.
6. Development sites which are located near canyon trails will provide access to those trails. Parking areas may be required by the planning commission at trailheads.
7. The maximum amount of impervious surface for streets and ways shall be twenty percent (20%) of the entire development site. All streets or rights of way for vehicular traffic shall be subject to the following limitations:
a. The maximum grade of such streets or rights of way shall be ten percent (10%) except as hereafter provided;
b. The mayor, after receiving a recommendation from the fire and engineering departments, may grant approval for a grade exceeding ten percent (10%). Grades shall not exceed the grade recommended by the city engineer for private streets;
c. The provisions of this subsection shall not apply to streets or rights of way already constructed or which have heretofore been granted preliminary approval by the planning commission;
d. Roads shall be designed to meet the city road base, asphalt and compaction standards.
G. Architectural Design:
1. Buildings proposed for construction in hillside or canyon areas within the Ogden City sensitive area zone shall be designed to be visually compatible with the natural beauty of the hillsides and canyons. The use of building materials in colors that will blend harmoniously with the natural settings are encouraged. Such material as natural woods, brick (earth colors) and stone are considered to be most appropriate.
2. The planning commission shall review the design and specified exterior materials and colors for all structures other than single-family dwellings. Building permits for such structures shall not be granted until building materials and colors have been approved by the planning commission.
3. Innovative designs for single-family dwelling units, e.g., earth sheltered dwellings with grass roofs, etc., may be allowed after approval by the planning commission, provided such innovations are also allowed under the city's building code, or that they have been granted the appropriate variances.
H. On Site Development: The property owner shall be fully responsible for making all improvements in accordance with the development site approval, e.g., drainage, erosion and vegetation constraints.
I. Bond: In addition to the provisions requiring the posting of a bond as set forth elsewhere in the ordinances of the city, the property owner/developer may be required by the mayor to guarantee the completion of revegetation projects, the stabilization of grading sites, cuts and fill and construction of stormwater runoff facilities, the construction of recreation centers as required in this section. If such additional bond is required, it shall be in an amount equal to the cost of construction of such projects and shall continue for one year after the completion date of such projects, improvements or facilities.
J. Exceptions: Exceptions to the requirements and provisions as outlined in this section may be approved by the mayor; provided, that the developer or owner of such development site can demonstrate to the satisfaction of the mayor that the requested exceptions shall not be detrimental to the general well being of the neighborhood nor in violation of the stated purposes in this chapter.
(Ord. 2011-39, 6-28-2011)
A. Conceptual Approval: All applications for a planned unit development, subdivision or other site plan shall comply with all applicable ordinances of the city. In addition, conceptual approval must first be granted by the planning commission prior to application for preliminary approval.
1. Submittal For Concept Approval:
a. Vicinity Map: Covers sufficient adjoining territory to indicate clearly nearby street patterns, property lines, other adjacent properties in the developer's ownership, and other significant features that will have a bearing upon the development;
b. Contour Map: Showing a proposed subdivision and street layout, existing substantial buildings, significant trees, watercourses, drainage ditches, storm or sanitary sewers with size and flow line elevation, water lines, gas lines, power lines, permanent easements, and other features that will have a bearing upon the design of the subdivision or on the provision of utilities.
2. Planning Commission Action: The planning commission may approve, approve with conditions, or deny the application for conceptual approval. Any approval by the planning commission shall specify which, if any, special studies and reports must be submitted for preliminary approval. Any concept denial shall include the reasons for such denial. This decision of the planning commission shall be final unless an interested party files an appeal to the mayor within fifteen (15) days of the planning commission's decision.
B. Preliminary Approval: Any individual seeking preliminary approval for development in the sensitive area overlay zone shall submit the following information to the planning commission for review:
1. Written Documents:
a. A legal description of the total site proposed for development, including a statement of present and proposed ownership and present and proposed zoning;
b. A statement of planning objectives to be achieved by the development through the particular approach proposed by the applicant. This statement should include a description of the character of the proposed development and the rationale behind the assumptions and choices made by the applicant;
c. A development schedule indicating the approximate date when construction of the project or stages of the project can be expected to begin and be completed;
d. A statement of the applicant's intentions with regard to the future selling or leasing of all or portions of the development;
e. Quantitative data for the following: total number and type of dwelling units; parcel size; proposed lot coverage of buildings and structures; approximate gross and net residential densities; total amount of open space (including a separate figure for usable open space);
f. Special studies as required by the Planning Commission under conceptual approval. These may include economic feasibility studies or market analysis, soil characteristics report, grading or erosion control plan, geologic report, vegetation preservation and protection report, hydrology and storm drainage and fire protection report (see Appendix A for study guidelines). All reports submitted herein shall be prepared by persons or firms licensed to practice their specialty or expertise in the State of Utah, if such license is required, or by one having demonstrable expertise in such field of practice.
2. Site Plans: Site plans shall include, in addition to the above provisions, the following:
a. Location of the proposed planned unit development, subdivision, cluster subdivision, or other development, with identification of abutting streets;
b. A slope map at a scale of one inch equals fifty feet (1" = 50') for development sites of less than ten (10) acres and a scale of one inch equals one hundred feet (1" = 100') for development sites of greater than ten (10) acres and a determination of the average slope of the proposed development;
c. The slope map referred to in subsection B2b of this Section shall also include a designation of all areas in the proposed development having a slope in excess of thirty percent (30%);
d. Topographic contours;
e. The total acreage, number of lots and proposed total density and average slope for residential developments;
f. The location and approximate size of the proposed lots;
g. A general street location, width, and grade of all proposed streets and radius of any cul-de-sacs;
h. Location of existing or proposed schools, churches, or parks;
i. Location of known hazards, (i.e., faults, drainage, rockfall, etc.) and the boundaries of the 100-year flood plain;
j. Soil type and general description;
k. Land use data, i.e., the amount of residential land, transportation land, etc., by acreage and percent;
l. Vegetative type map;
m. Existing and proposed utility lines (water, sanitary sewer and storm drains), etc.;
n. Proposed landscape plan, including the species identification and quantity of plants to be installed at the various locations throughout the site;
o. All engineering calculations performed and acquired pursuant to the provisions of the ordinances of the City shall be made available to the City Engineer as part of the review and approval process.
3. Planning Commission Action: After weighing all the evidence, the Planning Commission must take formal action, either approving the plan as presented, approving it subject to certain specified modifications, or disapproving it. A letter containing the Planning commission's recommendation shall then be forwarded to the mayor.
4. Mayoral Action: The mayor shall review and approve or disapprove all preliminary development plans in the sensitive area overlay zone.
C. Final Approval: Based on the establishment of compliance with the preliminary development plan through the review of finalized site plans and specifications, and the review of any materials required by the review authority, the planning commission shall approve, approve with modifications or disapprove the final site plan. Developments requiring the recording of subdivision, condominium or dedication plats must also have approval by the mayor.
1. Compliance With Preliminary Plan: The final development plan shall be deemed in substantial compliance with the preliminary development plan, provided modification by the applicant does not involve a change of one or more of the following:
a. Violate any provision of this chapter;
b. Vary the lot area requirement by more than ten percent (10%);
c. Involve a reduction of more than ten percent (10%) of the area reserved for common open space and/or usable open space;
d. Increase the floor area proposed for nonresidential use by more than ten percent (10%);
e. Increase the total ground area covered by buildings by more than five percent (5%);
f. Significantly alter the road system or on-site circulation pattern; or
g. Eliminate any recreational or community facilities approved in the preliminary plan.
2. Spot Elevations, Grading Plans: Application for final approval shall include with the improvement drawings, spot elevations on all lot corners or contour grading plans of all lot frontages. The scale will be the same as the improvement drawings.
(Ord. 76-15, 5-6-1976; amd. Ord. 85-27, 6-13-1985; Ord. 91-51, 12-1-1991; 1999 Code)
There shall be no construction, development or grading upon the development site until final approval has been granted, as provided in this section. Before the construction of single- family dwelling units upon lots shall be allowed, a plot plan drawn to scale (at least 1 inch equals 10 feet) for such lots shall be submitted to the building official, which plot plan shall show lot lines, existing and proposed contours at two foot (2') intervals, location of proposed single-family dwelling units, walks, driveways, patio areas. The plot plan will also show vegetation, drainage, and erosion controls and such plot plan shall be attached to the building permit.
(Ord. 76-15, 5-6-1976; amd. Ord. 85-27, 6-13-1985; Ord. 2001-32, 6-5-2001, eff. 6-30-2001)
A. Soil Characteristics Report: A soils report should be prepared by a person or firm qualified by training and experience which would furnish specific soil data for the property to be developed and methods that would control urban erosion. Data on the soil should include:
1. Soils map of the property involved, delineating the soil types;
2. An accurate slope map;
3. Major soil hazard ratings in relation to total area of development;
4. Percentage of area to be disturbed in relation to total area of development.
B. Grading Or Erosion Control: A grading or erosion control plan should accompany the development application showing the specific methods to be employed to control urban erosion and sedimentation and should include as a minimum:
1. The grading plan shall show present topography to include elevations, lines and grades including the location and depth of all proposed fills and cuts of the finished earth surfaces using a contour interval of two feet (2') or less. Access or haul road location, treatment and maintenance requirements shall be included;
2. The specific control practices to be employed on the disturbed area where necessary (includes seed mixes, types of mulches, etc.);
3. All calculations and proposed details used for design and construction (of debris basins, impoundments, diversions, dikes, waterways, drains, culverts and other water management for soil erosion control measures) shall be shown. Calculations shall employ predictions of soil loss from sheet erosion. Equations should include factors of:
a. Rainfall intensity and energy;
b. Soil stability;
c. Land slope and length of slope or topography;
d. Condition of the soil surface and land management practices in use;
e. Surface cover, grass, woodland, crop, pavement, etc.;
4. Specific dates on the length of time exposure for unprotected, cleared and graded areas;
5. A schedule showing when each stage of the project will be completed, including estimated starting and completion with reference to other stages of the project.
C. Geology: A geologic investigation of the site should be prepared containing the following information:
1. Location and size of subject area, and its general setting with respect to major geographic and/or geologic features;
2. The individual or agency who perform the geologic mapping upon which the report is based, and when the mapping was prepared;
3. Abundance, distribution, and general nature of exposure of earth materials within the area;
4. Nature and source of available subsurface information;
5. A geologic map should accompany the report and should delineate the following:
a. Rock composition and structural elements;
b. Surface and subsurface distribution of earth materials exposed or inferred within both bedrock and surficial deposits;
c. The nature and distribution of earth materials, faults, folds, slide masses, zones of contortion or crushing joints, fractures, shear zones, or other significant features;
6. Written recommendations for construction of proposed improvements to avoid impact of any potential geologic hazards.
D. Vegetation And Preservation Report: Vegetation preservation and protection report shall include:
1. Location and identification (by species) of existing vegetation;
2. The vegetation to be removed and method of disposal;
3. The vegetation to be planted;
4. Slope stabilization measures to be installed;
5. Analysis of the environmental effect of such operations including effects on slope stability, soil erosion, water quality, fish and wildlife, and fire hazard;
6. Topsoil stockpile areas will be designated;
7. Solar orientation is recommended for review.
E. Hydrology And Storm Drainage: A hydrology report should be prepared by a person or firm qualified by training and experience to have expert knowledge of the subject and should include an adequate description of the following:
1. A flood analysis should be made for all stream channels that occur on the site:
a. 100-year storm frequency based on rain on a saturated soil mantle or snow pack taking the results which cause the greater flood flow;
b. On streams with a meandering channel and relatively flat gradient way of the standard flood plain analysis of streams may be used (i.e., U.S. Corps of Engineers Standard Project Flood);
c. On mountain streams with relatively steep gradients only those analyses based on turbulent flow conditions may be used. "Bulking", if it occurs, must be recognized and channel cross sections increased to allow for it. Mud flows and other debris must also be considered in the analysis;
d. History of prior flooding;
e. Investigation of effects of short duration high intensity rain storms on the proposed storm drainage system will handle the predicted flows including the impact on areas below.
2. The ability of the existing stream channels to accommodate the estimated increase in storm flow due to the proposed development should be defined with respect to water flow and velocity. If the stream channel or banks are subject to erosion, measures to be taken to minimize this impact should be specified by consideration of the following:
a. The proposed streamside environment zone on the site plan and criteria for determining the zone must be delineated;
b. Natural flow patterns as they affect the proposed development should be described and evaluated;
c. Means by which the manmade drainage systems will deliver water to the natural channel systems should be specified.
3. Subsurface Hydrology:
a. The location and size of swamps, springs, and seeps shall be shown on the site plan and an investigation made to determine the reasons for the occurrence of these underground water sources. (An analysis of the vegetative cover or other surface information may be used to show the presence of underground water.)
b. Effects of the proposed development on subsurface water sources for areas immediately downstream should be defined and evaluated;
c. Effects of the proposed development on subsurface water sources for areas immediately downstream should be defined and evaluated;
d. If infiltration systems are proposed for handling increased flows caused by the proposed development, their operation and failure prevention measures should be described.
F. Fire Protection: A fire protection report should be prepared to assess fire probability and potential hazards by a person or agency qualified by training and experience. Elements of the report should include the following:
1. The width and approximate location of any easements required for access of fire protection equipment;
2. Agreements, if any, entered into by the applicant and a fire protection entity or other government agency that could have concerns about fire probability (State and Federal agencies);
3. The approval of the subdivision design and fire protection measures by the fire protection agency;
4. A letter from the chief of the fire protection entity stating:
a. Fire flow recommended by insurance service organizations;
b. The existing fire flow capability proposed to serve the project.
(Ord. 85-27, 6-13-1985; amd. 1999 Code)