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MGC recommends that design alternatives be considered which include directing peak flood <br />flows into portions of the impoundment area using internal berms to separate flood waters from <br />the existing free -water storage pool. This would provide temporary flood attenuation using the <br />available storage capacity within reclaimed portions of the impoundment, and would allow <br />optimizing of the size of an Auxiliary Overflow Structure that would work in tandem with the <br />existing Drop Structure. <br />6.3.2 Design of a Controlled Overflow from Ditch to Impoundment <br />For flood events larger than the 100 -year flood, overtopping would occur at uncontrolled <br />overtopping sections along the South Diversion Ditch, which could erode the berm significantly. <br />Although the impoundment can accommodate large volumes even up to the full PMF volume, it <br />is recommended that an evaluation be done, and if determined appropriate and necessary, <br />controlled (engineered) armored overflow (or multiple overflow) sections be designed and <br />constructed along the South Diversion Ditch berm to protect the channel from severe erosion <br />during flood overtopping. The location, number and sizes of these overflow structures should be <br />evaluated as part of an optimization process to efficiently convey storm water into the facility <br />along the various reaches of the channel. <br />6.4 RECOMMENDATIONS FOR ADDITIONAL INSPECTIONS AND MONITORING <br />In addition to regular inspections and monitoring required by Technical Revisions under the <br />Permit, it is recommended that camera inspections of the outlet pipes every 10 years be <br />conducted as recommended in the DWR Engineer's Inspection Report (DWR, 2013). <br />San Luis Project Miller Geotechnical Consultants <br />Tailing Dam Data Report 59 February 2014 <br />