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HomeMy Public PortalAboutCity of WildwoodCity of Wildwood, MO Friday, March 19, 2021 Chapter 425. Grading Section 425.050. Standards Safety Precaution. [R.O. 1997 § 425.050; Ord. No. 207 § 5, 2-26-1996; Ord. No. 221 § 3, 4-8-1996; Ord. No. 1488 § 1, 2-25-2008] A. All grading shall comply with the following requirements: 1. Surface Waters —Damage. Adequate provision shall be made to prevent any surface waters from damaging the cut face of an excavation or the sloping surface of a hill. 2. Retaining Walls —Cribbing. Retaining walls or cribbing shall be required whenever deemed necessary by the Department of Public Works to prevent the surface of any excavation or fill from exceeding at any point the maximum allowable slopes as set forth herein. 3. Drainage. All drainage provisions shall be of such design to carry surface waters to the nearest practical storm drain or natural watercourse as approved by the Director of Public Works as a suitable place to deposit and receive such waters. Where possible, water shall be dispersed by convex surfaces to dissipate water energy and velocity and disperse volume over a greater surface area before being carried to a storm drain or watercourse. 4. Protection Of Streets, Property. No excavation shall be made so close to the property line to endanger any adjoining public or private street without supporting and protecting such public or private street or property from settling, cracking or other damage. 5. Fill Location. No fill shall be made so as to cause or to allow the same to be deposited upon or to roll, flow or wash upon or over the premises of another without the express written consent of the owner of such premises so affected; or upon or over any public street, walk, place or way; nor so close to the top of a bank of a channel as to create the possibility of bank failure and sliding. 6. Materials. Materials for fills shall consist of material obtained from excavation of banks, borrow pits or other approved source. Material shall consist of clean uncontaminated earth, soil, dirt, sand, rocks, gravel or masonry materials only, shall be free of vegetable matter and deleterious material and shall not contain large rocks or lumps. Materials for roadways are not covered by this Chapter as per exceptions in Section 425.030. 7. Minimum Standards. Minimum standards of excavations and fills shall be as follows: a. No excavation shall be made with a cut face steeper in slope than three (3) horizontal to one (1) vertical. b. No fill shall be made which creates an exposed embankment face steeper in slope than three (3) horizontal to one (1) vertical. The embanked end of the fill shall be uniformly compacted as provided in Subsection (A)(8) hereof and stable under the proposed conditions. 8. Minimum Standards —Land Disturbance. Unless modified as may be permitted in this Subsection (A)(8) or by provisions of Subsection (A)(9) (b) hereof, minimum standards for land disturbance shall be as follows: a. No land disturbance shall occur within fifty (50) feet of any creek, stream, water runoff channels or ravines or in other areas determined by the Director or his/her designees to be highly sensitive or subject to erosion or flooding, except as necessary for construction pursuant to an approved final site plan, planned zoning development, or conditional use permit specifically authorizing the modification of this standard and necessitating exception to this minimum standard. b. No land disturbance shall occur on terrain that does not satisfy the minimum standards for excavation or fill, except as necessary for construction pursuant to an approved final site plan, planned zoning development, or conditional use permit specifically authorizing the modification of this standard and necessitating exception to this minimum standard. c. No land disturbance shall occur on any property or lot line or within the area of building setback required by applicable zoning or subdivision regulations, except as necessary for construction pursuant to an approved final site plan, planned zoning development, or conditional use permit, or approved subdivision plat specifically authorizing the modification of this standard and necessitating exception to this minimum standard. d. No land disturbance shall occur which shall cause a nuisance to any adjoining property owner, or which shall violate any Federal, State or local law or regulation. The Director of Public Works, in conjunction with the Department of Planning, shall establish regulations for the granting of permits so as to enforce this Chapter and ensure that any grading is completed with minimum erosion, aesthetic degradation or other negative impact on the site or surrounding areas or the community. e. Clearing techniques that retain existing vegetation to the maximum extent practicable shall be used and the time period for disturbed areas to be without vegetative cover shall be minimized to the extent practical. f. Clearing, except that necessary to establish sediment control devices, shall not begin until all sediment control devices have been installed and have been stabilized. 9. Phasing shall be required on all sites disturbing greater than thirty (30) acres of land. The size of each phase will be established by the Department of Public Works at the time of plan review for the issuance of a grading permit. h. The Director of Public Works, in conjunction with the Department of Planning, shall establish such other minimum standards as may be necessary to protect grand trees or specimen vegetation or land features or to otherwise effect the purposes of this Chapter. 9. Minimum Standards—AII Grading. a. All grading shall comply with the restrictions and prohibitions set forth in the Natural Resource Protection Standards of the Subdivision Code (see Chapter 420), all requirements of the Tree Preservation and Restoration Code (see Chapter 410 of this Code), and other applicable zoning (see Chapter 415) and subdivision regulations (which are on file in the City offices) pertaining to the site or development. No grading permit shall be issued on any site where there is an existing uncured violation of any provision of the zoning, subdivision or other development regulations of the City of Wildwood. b. Modifications. Any party seeking a permit may request a modification of any of the minimum standards set forth in Subsection (A)(7) or (8) hereof by filing a written request with the Director specifically identifying: (1) Unique or unusual characteristic(s) of the site, not generally applicable, that eliminate the need for full application of the standard, or (2) The precise mitigation proposed that would fully rectify the harms addressed by the minimum standard to be modified. The Director may make such modification upon a determination that such facts exist qualifying for such modification; provided that no modification shall be permitted that shall circumvent any other applicable regulation or the intent of these minimum standards to eliminate the detrimental impact of grading addressed by each such standard. c. Erosion Control Design. Erosion control requirements shall include the following: (1) Soil stabilization shall be completed within five (5) days of clearing or inactivity in construction. (2) If seeding or another vegetative erosion control method is used, it shall become established within two (2) weeks or the site shall be reseeded or a non -vegetative option employed. (3) Techniques shall be employed to ensure stabilization on steep slopes and in drainageways. (4) Soil stockpiles must be stabilized or covered at the end of each workday or perimeter controls must be in place to prevent silt from the stockpile from leaving the site. (5) The entire site must be stabilized, using a heavy mulch layer or another method that does not require germination to control erosion, at the close of the construction season. No new grading shall commence after the close of the construction season and before the start of the next construction season, unless authorized by the Director of Public Works in accordance with Section 425.050(A)(9)(b) of this Chapter; except for minimum necessary grading for the foundation or basement of any building, structure or swimming pool for which a building permit has been duly issued. (6) Techniques shall be employed to prevent the blowing of dust or sediment from the site. (7) Techniques shall be employed to divert upland runoff past disturbed slopes. d. Sediment Control Design. Sediment control requirements shall include: (1) Settling basins, sediment traps or tanks and perimeter controls. (2) Settling basins shall be provided for each drainage area within ten (10) or more acres disturbed at one time and shall be sized to contain one-half (0.5) inch of sediment from the drainage area and be able to contain a two-year, 24 -hour storm. If the provision of a basin of this size is impractical, other similarly effective best management practices (BMP), as evaluated and specified in the Storm Water Pollution Prevention Plan (SWPPP), shall be provided. Settling basins shall be designed in a manner that allows adaptation to provide long-term stormwater management as required by the City. (3) (4) Settling basins shall have stabilized spillways to minimize the potential for erosion of the spillway or basin embankment. Protection for adjacent properties by the use of a vegetated buffer strip in combination with perimeter controls. (5) e. Watercourse Design. Watercourse protection requirements shall include: (1) Encroachment into or crossings of active watercourses/riparian areas and wetlands shall be avoided to the maximum extent practicable. All City, State and Federal permits and approvals shall be obtained by a permit holder prior to beginning work authorized by a City grading permit. (2) Stabilization of any watercourse channels before, during and after any in -channel work. If a defined watercourse is to be realigned or reconfigured, clearing and grubbing activities within fifty (50) feet of the watercourse shall not begin until all materials and equipment necessary to protect the watercourse and complete the work are on site. Once started, work shall be completed as soon as possible. Areas within fifty (50) feet of the watercourse shall be recontoured and revegetated, seeded or otherwise protected within five (5) working days after land disturbance activities have ceased. (3) (4) All stormwater conveyances shall be designed according to the criteria of the St. Louis Metropolitan Sewer District (MSD) and the necessary MSD permits obtained. (5) Stabilization adequate to prevent erosion shall be provided at the outlets of all pipes and paved channels. f. Construction Site Access Design. Construction site access requirements for land disturbance greater that one (1) acre shall include: (1) A temporary access road provided at all grading sites including a wash down area supporting all active sites. (2) The Department of Public Works may require other measures to ensure that construction vehicles do not track sediment onto public streets or be washed with wash effluent channeled directly into storm drains. 10. Compaction. All fills intended to support buildings or structures, sewers and conduits shall be compacted to a minimum of ninety percent (90%) compaction as determined by Modified Proctor, ASTM D-1775. Compaction of fills for these uses must be certified by a registered professional engineer at the owner's expense. Frequency of compaction tests is to be determined by the Director of Public Works. Compaction of other fills shall be required where necessary as a safety measure to aid in preventing the saturation, slipping or erosion of the fill. The requirements of the Director of Public Works for the compaction of fills shall include, but shall not be limited to, the following: a. Areas to be graded by cutting or filling shall be rough graded to within two -tenths (2/10) of a foot of accepted elevation after allowance has been made for thickness of topsoil, paved areas and other installations. b. The natural ground surface shall be prepared by removing topsoil and vegetation and by compacting the fill upon a series of terraces. Hillside or slope fills shall require plowing or scarification of original ground. c. Grading of slopes will require silt fencing at intermediate levels to slow surface water, prevent rutting and decrease erosion. d. Grading sites will require silting basins to prevent mud from washing onto adjacent properties. e. If fill material moisture content is below the requirement for compacting to maximum practical density, water in the proper amount shall be added. If moisture content is too great, fill material shall be aerated by blading or other satisfactory methods to reduce moisture content. f. Frozen materials or soft, mucky, friable, easily compressible materials shall not be incorporated in fills intended to support buildings, structures, sewers or conduits or in the embanked ends of fills. In heavy rain, interrupted work shall not be resumed until moisture content is satisfactory. Fill material shall not be placed, spread or rolled while the ground is frozen or thawing. g. The maximum uncompacted thickness of layers of the fill to be compacted shall not exceed eight (8) inches. h. Compaction shall be by tamping, sheepsfoot rollers, multiple wheel pneumatic or other type rollers. Rolling shall be continuous until the desired maximum density is obtained. i. Topsoil disturbed by grading or building operations shall be stripped and piled for storage in an amount necessary to complete finished grading only. 11. Removal Of Timber, Rubbish, Etc. Timber, logs, trees, brush, vegetable matters and rubbish of any description shall be removed and disposed of so as to leave the disturbed area with a neat and finished appearance. Tree stumps, masonry and other obstructions shall be removed to the following depths: Paved areas —Two (2) feet below subgrade Lawn areas —Two (2) feet below finished grade Solid rock, shale or similar materials shall be removed to a depth of fifteen (15) inches below subgrade for paved area and two (2) feet below finish grade for lawn area except where it is impractical because of rock outcropping. 12. Storm Water Pollution Prevention Plan (SWPPP) Required For Land Disturbance Greater Than One Acre In Area. All applications for grading permits for land disturbance greater than one (1) acre in area shall be accompanied by a Storm Water Pollution Prevention Plan (SWPPP) prepared for the specific site by or under the direction of a qualified professional. The application shall contain a statement that any land clearing, construction or development involving the movement of earth shall be in accordance with the Storm Water Pollution Prevention Plan and the applicant will assume and acknowledge responsibility for compliance with this Code and the Storm Water Pollution Prevention Plan at the site of the permitted activity. a. Content. The Storm Water Pollution Prevention Plan (SWPPP) shall comply with the standards established herein and shall include the following: (1) Name, address and telephone number of the site owner and the name, address and telephone number of the individual who will be in overall responsible charge of construction/development activities at the site. (2) Site address or location description and parcel identification number(s). A site map showing the outlines of the total project area, the areas to be disturbed, existing land uses, locations and names of surface water bodies, locations of flood plains, locations of temporary and permanent best management practices (BMP) and such other information as may be required by the City. (4) Existing contours of the site and adjoining strips of off -site property and proposed contours after completion of the proposed land disturbance and development, based on United (3) States Geological Survey datum, with established elevations at buildings, walks, drives, streets and roads; and information on necessary clearing and grubbing, removal of existing structures, excavating, filling, spreading and compacting. (5) A natural resources map identifying soils, forest cover and resources protected under other provisions of City ordinances. (6) An estimate of the runoff coefficient of the site prior to disturbance and the runoff coefficient after the construction addressed in the permit application is completed. (7) Estimated quantity of land to be disturbed. (8) Details of the site drainage pattern both before and after major land disturbance activities. (9) Access to construction site. (10) Description of best management practices (BMP) to be utilized to control erosion and sedimentation during the period of land disturbance. (11) Description of best management practices (BMP) to be utilized to prevent other potential pollutants such as construction wastes, toxic or hazardous substances, petroleum products, pesticides, herbicides, site litter, sanitary wastes and other pollutants from entering the natural drainageways during the period of construction and land disturbance. (12) Description of best management practices (BMP) that will be installed during land disturbance to control pollutants in stormwater discharges that will occur after land disturbance activity has been completed. (13) Location of temporary off-street parking and wash down area for related vehicles. (14) Sources of off -site borrow material or spoil sites and all information relative to haul routes, trucks and equipment. (15) The anticipated sequence of construction and land disturbance activities, including installation of best management practices (BMP), removal of temporary best management practices (BMP), stripping and clearing; rough grading; construction utilities, infrastructure and buildings; and final grading and landscaping. Sequencing shall identify the expected date(s) on which clearing will begin, the estimated duration of exposure of cleared areas, areas of clearing, installation of temporary erosion and sediment control measures and establishment of permanent vegetation. (16) All erosion and sediment control measures necessary to meet the objectives of this code throughout all phases of construction and after completion of site development. Depending upon the complexity of the project, the drafting of intermediate plans may be required at the close of each season. (17) Seeding mixtures and rates, types of sod, method of seedbed preparation, expected seeding dates, type and rate of lime and fertilizer application and kind and quantity of mulching for both temporary and permanent vegetative control measures. (18) Provisions for maintenance of control facilities, including easements and estimates of the cost of maintenance. (19) Plans for responding to any loss of contained sediment to include the immediate actions the permit holder will take in case of a containment failure. This plan must include documentation of actions and mandatory reporting to the Department of Public Works. (20) Schedules and procedures for routine inspections of any structures provided to prevent pollution of stormwater or to remove pollutants from stormwater and of the site in general to ensure all best management practices (BMP) are continually implemented and are effective. b. Required Plan Amendments —Storm Water Pollution Prevention Plan (SWPPP). The permit holder shall amend the Storm Water Pollution Prevention Plan whenever: (1) Design, operation or maintenance of best management practices (BMP) is changed; (2) Design of the construction project is changed that could significantly affect the quality of the stormwater discharges; (3) Site operator's inspections indicate deficiencies in the Storm Water Pollution Prevention Plan (SWPPP) or any best management practices (BMP); (4) Inspections by City or by the Missouri Department of Natural resources indicate deficiencies in the Storm Water Pollution Prevention Plan (SWPPP) or any best management practices (BMP); The Storm Water Pollution Prevention Plan (SWPPP) is determined to be ineffective in significantly minimizing or controlling erosion or excessive sediment deposits in streams or lakes; (5) (6) The Storm Water Pollution Prevention Plan (SWPPP) is determined to be ineffective in preventing pollution of waterways from construction wastes, chemicals, fueling facilities, concrete truck washouts, toxic or hazardous materials, site litter or other substances or wastes likely to have an adverse impact on water quality; (7) Total settleable solids from a stormwater outfall exceeds one- half (0.5) ml/L/hr if the discharge is within the prescribed proximity of a valuable resource water as defined by the Missouri Department of Natural Resources; (8) Total settleable solids from a stormwater outfall exceeds two and one-half (2.5) ml/L/hr for any other outfall; or (9) The City or the Missouri Department of Natural Resources determines violations of water quality standards may occur or have occurred. c. Permit Holder Responsibilities For Administration Of Storm Water Pollution Prevention Plan (SWPPP). The permit holder shall: (1) Notify all contractors and other entities (including utility crews, City employees or their agents) that will perform work at the site of the existence of the Storm Water Pollution Prevention Plan (SWPPP) and what actions or precautions shall be taken while on site to minimize the potential for erosion and the potential for damaging any best management practices (BMP); (2) Determine the need for and establish training programs to ensure that all site workers have been trained, at a minimum, in erosion control, material handling and storage and housekeeping; Provide copies of the Storm Water Pollution Prevention Plan (SWPPP) to all parties who are responsible for installation, operation or maintenance of any best management practices (BMP); and (4) Maintain a current copy of the Storm Water Pollution Prevention Plan (SWPPP) on the site at all times. (3)