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• Area 8 <br />The dugout pond contains the run-off from topsoil stockpile #1. The <br />drainage area for the dugout pond is comprised predominantly of lush <br />orchard grass. Of the 0.4 acre area, an estimated 0.3 acres is lush <br />grasses with ground cover that is almost 1008. The south facing slope <br />of the topsoil pile is relatively bare with poor to fair ground cover. <br />Two curve numbers were selected for this area. A curve number of 74 was <br />selected for 0.3 acres of lush vegetation and a curve number of 82 was <br />selected for the 0.1 acre south facing slope. <br />Area 9 - Small Area Exemption #1 <br />Area 9 is the outslope of the facilities pad, the loadout facility, and <br />the railroad spur track. This area encompasses 3.2 acres. It would be <br />very difficult to construct a sediment pond below this area to collect <br />the run-off from it. For this reason alternative sediment control ie <br />provided as shown on Map 14. There is no reason to suspect this area <br />contains acidic, toxic, or alkalinity forming materials. Drainage from <br />the outslope area would flow down the face of the embankment and then <br />course along the toe of the embankment into one of two culverts. Run-off <br />from the track area will generally flow west on the north side of the <br />tracks to one of four culverts. In all cases, run-off will pass through <br />a sediment fence before it flows into the culverts. <br />Sampling points SAE-1, SAE-2, SAE-3 and SAE-4 as shown on Map 19, will <br />be established at the outlet of the four culverts to confirm that run-off <br />from the small area exemption meets the effluent limitations for <br />• downstream receiving waters. Before samples are collected, it will be <br />determined if irrigation water is causing or supplementing the flow at <br />the small area exemption sample point. If irrigation water is <br />influencing the flow, then an upstream irrigation water sample will be <br />taken at one of the sample points show on Map 14. Upstream irrigation <br />water samples will be analyzed for settleable solids. Samples from the <br />small area exemption sample points will be collected, if available, <br />during a significant precipitation event and during spring snowmelt to <br />confirm compliance. After two samples have been taken that confirm <br />compliance, no further sampling will be performed unless further sampling <br />is required by the Division. Samples not influenced by irrigation water <br />will be in compliance if they contain settleable solids levels of 0.5 <br />ml/1 or less. Samples influenced by irrigation water will be in <br />compliance if they contain settleable solid levels of no more than the <br />settleable solid level contained in the upstream irrigation water sample <br />plus 0.5 ml/1. <br />Sediment Pond <br />The run-off calculations presented on pages 5, 7 and 8 show that the <br />sediment pond must contain 0.48 acre-feet of water, 0.05 acre-feet of <br />sediment and the emergency spillway must be designed to pass 8.62 cfs. <br />The existing sediment pond has water capacity of 0.84 acre-feet and a <br />sediment capacity of 0.19 acre-feet, See Map 7, Sedimentation Pond <br />Design. The capacity of the sediment pond is therefore adequate to <br />contain the design event and the calculated sediment loading. <br />• <br />-3- 6/03/93 <br />