Ord 2002-046 - Laserfiche WebLink

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however, that the cessation of work related to the required modification shall continue for the duration of the appeal. Sec. 94.105. Runoff attenuation. (a) Under this article, all drainage channels on the site shall be designed to minimize potential erosion. (b) The following runoff attenuation strategies and techniques shall be used: (I) All constructed and altered drainage channels shall be stabilized and vegetated immediately after final grading. (2) Effective energy dissipation techniques must be used at inlets to and outlets from ponds. Inlets to ponds must also have sediment traps, with a wall or gabions, designed to trap the bulk of sediments and facilitate sediment removal. (3) Velocity checks must be made on channel slopes over two percent. (4) For channels with slopes over three percent and with non-erodable velocities (less than 6 feet per second), a rock pilot channel must be used to stabilize the channel bed. (5) Manhole/sediment and litter traps are required at the discharge point of parking areas for commercial uses. (6) Storm drain inlets for all development except for single-family and two-family residential development must be equipped with inlet baskets to capture litter from parking areas. (c) Drainage facilities will be designed and constructed so that +lhe rate of runoff after construction shall be equal to or less than the site's runoff prior to construction. Rate of runoff shall be computed on a 25-year storm peak flow using the City of Austin Drainage Criteria Manual, if a separate water quality pond is required for the development. If a separate water quality pond is not required, the rate of runoff shall be computed on both a two-year and a 25-year peak storm flow using the City of Austin Drainage Criteria Manual , as of the effective date of the ordinance from 'Nhich this article derives. Computation of the rate of runoff shall be based on an assumption of a fully developed contributing drainage area or watershed. Sec. 94.106. Wastewater collection and disposal. (a) Organized sewer systems. All construction of sewer systems within developments requiring compliance with this article shall comply with the special standards of section VII- B of the City of Austin manual, Standard Specifications for Water and Waste Water Utility Construction, as of the effective date of the ordinance from which this article derives. If the system is over the Edwards Aquifer recharge zone, construction standard specifications for C:\TEMP\Drainage Interim Amendments.doc 7