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<br />precipitation event, as shown in Hahibit 3, Sediaent Control Plan. <br />The criteria used to determine the amount of runoff tributary to the <br />ponds is Antecedent Moisture Condition II, which provides for <br />average precipitation and soil moisture conditions preceeding the <br />design precipitation event. As stated in SCS Technical Release No. <br />55, (I977), Procedures for Determining Peak Flows in Colorado, <br />"The amount of precipitation occurring five days preceding a storm <br />in question is an indication of the antecedent moisture condition <br />(AMC) of the soil. The moisture condition generally used is the <br />average, AMC II. Antecedent Moisture Conditions I and III should <br />not be used for design purposes. They may apply in a case where <br />reproduction of a particular historical event is desired." The use <br />of ANC II is a well-documented design procedure, and dcea provide <br />for runoff entering the ponds in addition to the 25-year, 24-hour <br />storm runoff. The conservative design of the detention basins, as <br />compared to the design criteria for sedimentation ponds, eliminates <br />the need for specific maintenance provisions in the sediment control <br />plan. <br />5. On page 2.05-162, it is stated that the detention basins will be <br />monitored at inlet and outlet. Will each inlet be monitored? <br />RSSPONSS: <br />The purpose of monitoring water quality at the inlet and outlet <br />of the ponds is to determine sediment trap efficiency and the <br />effects of detention on water salinity. The water in the <br />impoundments will be sampled near the point of major inflow and at <br />the discharge point. <br />-29- <br />