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DRAFT <br />Storm Water Management and Urban <br />660 Sediment Pollution Abatement S stems 927.07 <br />(a) All materials and components used for the construction of a stormwater storage <br />facility shall conform to the latest version of the LJNIFORM STANDARDS FOR SEWERAGE <br />IMPROVEMENTS or other approved standards and, where necessary, shall be designed to <br />support a standard H-20 wheel load if the facility is located under a roadway, drive or parking <br />area. <br />Corrugated metal pipe shall have annular ends with matching bands, gasket joints, and <br />watertight seams. All plate bulkheads over 24" in diameter shall be reinforced with external <br />braces and stiffeners. Corrugated metal pipe shall be galvanized or aluminized. <br />Reinforced concrete pipe used for storage facilities shall have premium joints and shall <br />have endwalls or bulkheads designed to resist anticipated loads. <br />Access manholes with access steps shall be provided at each end of an underground <br />storage facility and at intermediate points, if deemed necessary by the City Engineer. The invert <br />elevation of the storage facility outlet and the restrictor pipe shall be aligned in such a manner to <br />eliminate the creation of a sump within the storage facility. <br />Pipe installation methods and bedding materials shall conform to those recommended in <br />the LTNIFORM STANDARDS FOR SEWERAGE IMPROVEMENTS. <br />(b) Infiltration basins, also known as stone beds, shall only be approved subject to the <br />following standards: <br />(1) A report shall be submitted from a certified testing laboratory containing <br /> sufficient records and data to establish the character of the soil. Such <br /> records shall describe the soil conditions found to a depth of at least five <br /> feet (5') below the deepest point proposed for the installation of the stone <br /> bed or dissipation wells. The report shall include information regarding <br /> the level of the water table and soil permeability. <br />(2) The stone bed shall be located a mimmum of twenty feet (20') from any <br /> building or ten feet (10') from any property line or sanitary sewer <br /> <br />(3) easement. <br />An approved filter fabric shall cover the top and sides of the stone bed <br /> <br />(4) . <br />The required volume of the stone bed shall be calculated using approved <br /> terms for coefficient of runoff, drainage area, storm intensity and time of <br /> concentration. The porosity ratio shall be 0.33 to figure net volume from <br /> the gross volume. <br />(5) An observation well shall be required for inspection purposes. The <br /> location and diameter shall be approved by the Engineering Department. <br />The observation well shall be as deep as the deepest part of the stone bed <br /> <br /> <br />(6) . <br />Perforated pipe may be approved for use in an observation well. <br />The infiltrahon basin shall have a sump pump to dischar <br />e exc <br />t <br /> g <br />ess wa <br />er to <br />an approved storm sewer or ditch. <br />(c) All storm water flow from the proposed development, including flows from <br />upstream areas passing through, and further including increased flow attributable to changes in <br />time of concentration or changes in the former runoff factor (imperviousness), shall be conveyed <br />to the proper storage facility end outlet for the entire tributary area via a natural channel or <br />pipe/culvert either or both of which shall be improved so as to be of adequate capacity. <br />(d) One foot of freeboard shall be provided in wet ponds above the 100-year storm <br />water level. (Ord. 2006-15. Passed 2-21-06.)