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EXHIBIT A: EXISTING CHAPTER 927 <br />Storm Water Management and Urban <br />66M Sediment Pollution Abatement Systems 927.06 <br />(e) The rainfall intensity shall be based on Table 1 entitled "Standard Rainfall <br />Intensity Duration Table". <br />(f) If the volume of runoff is greater after development than before development, the <br />peak rate of runoff shall be reduced. The critical storm shall be determined by the percent <br />increase in runoff volume. The peak rate of runoff from the critical storm and all more frequent <br />storms, shall be no greater than ninety percent (90%) of the peak rate of runoff from the one year <br />storm occurring before any development. Runoff rates from less frequent storms (longer return <br />periods) than the critical storm shall satisfy the requirements in Paragraph (b) of this Section. <br />(g) The critical storm for a specific development area is determined as follows: <br />(1) Determine the total volume of runoff from a twenty -four-hour one year <br />frequency storm, occurring on the development area based on the <br />difference between after development and ninety percent (90%) of before <br />any development. <br />(2) From the volumes in Paragraph (c) of this Section, determine the percent <br />of increase in volume of runoff due to development and, using this <br />percentage, select the critical storm from the following table: <br />If the percentage increase in volume of runoff is: <br />The "critical storm" <br />Equal to or and for discharge <br />Greater than Less than limitation will be: <br />0 <br />10 <br />1 <br />Year <br />10 <br />20 <br />2 <br />Years <br />20 <br />50 <br />5 <br />Years <br />50 <br />100 <br />10 <br />Years <br />100 <br />250 <br />25 <br />Years <br />250 <br />500 <br />50 <br />Years <br />500 <br />--- <br />100 <br />Years <br />(h) The minimum storage volume for the stormwater retention system shall be <br />calculate following the requirements of subsections (a) through (g) above. However, in no case <br />shall the required storage volume be less than the total proposed hardsurface area of the site <br />times two inches. Hard surface areas shall include roof areas, concrete areas, asphalt areas, brick <br />areas, stone paver areas, and other similar areas as determined by the City Engineer. <br />(i) The requirements shall be satisfied at each location where runoff leaves the <br />development area. The runoff rates and volumes shall be considered for both the conditions <br />before development and after development at each of these locations. <br />0) To ensure the continued functioning of stormwater control structures, the <br />following information shall be identified to the satisfaction of the City Engineer. <br />(1)The person or entity responsible for continued maintenance of the stormwater <br />control structure and the mechanism establishing responsibility; <br />(2)Maintenance requirements and Schedules; and <br />(3)Permanent access and access easements required to perform inspection and <br />maintenance of stormwater control structures and stormwater conveyance <br />systems if easements are required by City. The minimum size of an <br />easement shall be approved by the City Engineer. <br />