2003-086 Ordinance - Laserfiche WebLink

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?;.... Ordinance No. 2003-86 (g) The critical storm for a specific development area is determined as follows: (1) Determine the total volume of runoff from a twenty- four-hour one year frequency storm, occurring on the development area based on the difference between after development and ninety (90%) percent of before any development. (2) From the volumes in Paragraph (c) of this Section, determine the percent of increase in volume of runoff due to development and, using this percentage, select the critical storm from the following table: If the percentage increase in volume of runoff is: The "critical storm" Equa1 to or and for discharge Greater than Less than limitation will be: 0 10 1 Year 10 20 2 Years 20 50 5 Years 50 100 10 Years 100 250 25 Years 250 500 50 Yeazs 500 --- 100 Years (h) The minimum storage volume for the stormwater retention system shall be calculated following the requirements of subsectians (a) through (g) above. However, in no case shall the required storage volume be less than the total proposed hardsurface azea of the site rimes two inches. Hard surface areas shall include roof areas, concrete areas, asphalt areas, brick areas, stone paver areas, and other similar areas as determined by the City Engineer. (i) The requirements shall be satisfied at each location where runoff leaves the development area. The runoff rates and volumes shall be considered for both the conditions before development and after development at each of these locations. (i) To ensure the continued functioning of stormwater control structures, the following information shall be identified to the satisfaction of the City Engineer. (1)T'he person or entity responsible for continued maintenance of the stormwater cornrol structure and the mechanism establishing responsibility; (2)Maintenance requirements and Schedules; and (3)Permanent access and access easements required to perform inspection and maintenance of stormwater control structures and stormwater conveyance systems if easements are required by City. T'he minimum size of an easement shall be approved by the City Engineer. (k) Methods for controlling increases in stormwater runoff peaks and volumes shall be proposed that may include but are not limited to: (1) Retarding flow velocities by increasing friction; for example, grassed road ditches rather than paved street gutters where practical, low density development areas, access roads, etc.; or grass- and rock-lined dramage channels; 15