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aoox 9 ?Aa 235 <br />ORDINANCE 95-10 <br />(a) Hydrologic data including design rainfall, project <br />drainage area, tributary offsite drainage area, <br />percolation tests, existing and proposed impervious <br />area and soil characteristics including depth to <br />wet season high water table. Soil boring at four <br />hundred (4001) feet spacing to a depth of six (61) <br />feet shall be provided. Alternate representative <br />soil profiles may be used if approved in writing by <br />the Public -Works Director and if demonstrated to be <br />from a reliable and generally recognized source. A <br />one foot interval contour topographic map of <br />development area including offsite area of <br />sufficient size to indicate the general neighboring. <br />_elevations, drainage patterns and transition grades <br />shall be provided. Justification for wet season <br />water table assumptions shall be provided. <br />(b) Hydrologic calculations for determining existing <br />and proposed stormwater runoff. <br />(c) Hydraulic data including receiving water stages, <br />stage -storage and stage -discharge data for proposed <br />retention and/or detention facilities, and <br />percolation test data as per the following <br />procedure: <br />1. The test holes shall be located as close as <br />possible to the proposed location of <br />exfiltration trench or other 'percolation <br />facility (vertical and horizontal) and, if <br />critical, to a depth two (21) feet below the <br />water table at the time of the test. <br />2. A hole for each test of approximately twr}ve <br />(12") inches diameter (or as required fur a <br />maximum clearance of one-half (}") inch <br />between the hole and test casing) is excavated <br />to the required depth and the casing is <br />lowered into the hole with a minimum of twelve <br />(12") inches extending above the surface of <br />the grade. <br />3. The test casing shall consist of a pipe that <br />is a.least eight (811) inches in diameter with <br />perforations in approximately the bottom <br />seventy-five (75%) percent of the length as <br />measured from the surface. The bottom of the <br />casing shall be pointed. Exfiltration <br />increments shall be measured with a suitable <br />gauging device. <br />4. Fill the test bore to six (611) inches above <br />the surface of the existing grade and run the <br />test no later than two (2) hours after the <br />level has exfiltrated to below surface of <br />existing grade. In all cases test runs are to <br />start only after the first two (211) inches <br />have exfiltrated. If a dry season condition <br />exists, the test shall begin when the soil is <br />moist and a wet season is simulated. <br />18 <br />MAY 319 1995 <br />M M M <br />