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Criteria Manuals are used to manage construction and post <br />construction stormwater runoff quality to levels that would be the <br />same or better quality as would result from a cut or fill of not <br />more than four feet. The City Council may approve a variance for <br />a cut or fill greater than eight feet based on a variance petition <br />submitted in accordance with Article 10, Division 2 of this Chapter <br />1. The cut and fill requirements under this section may not be <br />modified through a petition for a Planned Development District. <br />SECTI ®N 7. Chapter 5, Environmental Regulations, Article 1, General Provisions, <br />Section 5.1.1.3, Runoff Attenuation, is amended to read as follows: <br />Section 5.1.1.3 Runoff Attenuation <br />(a) Techniques to Minimize Erosion. Under this Chapter, all drainage <br />channels on the site shall be designed to minimize potential erosion. In addition to <br />standards in Section 5.1.1.2, the following runoff attenuation strategies and <br />techniques shall be used: <br />(1) All constructed and altered drainage channels shall be stabilized <br />and vegetated immediately after final grading. <br />(2) Effective energy dissipation techniques must be used at inlets to <br />and outlets from ponds. Inlets to ponds must also have sediment <br />traps, with a wall or gabions, designed to trap the bulk of <br />sediments and facilitate sediment removal. <br />(3) Velocity checks must be made on channel slopes over 2 %. <br />(4) For channels with slopes over three percent and with non - erodible <br />velocities (less than six feet per second), a rock pilot channel must <br />be used to stabilize the channel bed. <br />(5) Sediment and litter traps are required at the discharge point of <br />parking areas for commercial, industrial, and multifamily uses. <br />(6) Storm drain inlets for all development except for single - family and <br />two - family residential development must be equipped with inlet <br />baskets to capture litter from parking areas. <br />(b) Detention Required. Drainage facilities will be designed and <br />constructed so that the rate of runoff at each existing discharge location from a <br />site after construction shall be equal to or less than the runoff prior to construction <br />for the 2, 10, 25 and 100 -year storm frequencies. Rate of runoff shall be- eempated <br />on a 25 year- stefm peak flew and facility design features shall be desi ned <br />by using the City of San Marcos Stormwater Technical <br />Manual, if . I€-a <br />