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feasible. That flow will be rerouted to EMP008a and EMP007. These changes and <br />modification to the existing detention pond in Squaw Gulch (EMP007) comprise the <br />third management basin addressed in this report. <br />Inflow Design Storms and Design Criteria <br />The criteria that was used to evaluate the effects of the MLE on storm water and <br />• <br /> <br />management thereof are the same as have been previously used at the Cresson Project <br />(through Amendment No. 8) and have been used by Golder Associates, Inc. and Smith <br />Williams Consultants, Inc. for the design of storm water management for the VLF facility. <br />The criteria are only briefly reiterated herein since they have been previously adopted <br />and accepted by regulating agencies. <br />The Inflow Design Storm (IDS) criteria are based on two events. The <br />precipitation depth/duration values for both events are derived from the NOAA~ Atlas, <br />which is universally used for moderate storm determinations. The capacity of each <br />pond will be twice the volume of the 10-year/24-hour storm (2.7 inches). The spillways <br />from those ponds and engineered diversion channels are designed to allow the runoff <br />from a 100-year/24-hour storm with a total precipitation depth of 3.5 inches in 24-hours. <br />Runoff Coefficients <br />The runoff coefficients used in the SEDCAD4 model were consistent with those <br />incorporated in previous evaluations for the Cresson Project. One exception is that a <br />higher number was used for the proposed ECOSA (at Curve Number ("CN") 75) <br />because it is proposed to have and engineered and constructed less permeable sub- <br />soils than the CN 66 that is 'used for SGOSA and SGOSAE. A summary of the CN <br />values is as follows: <br />• Existing wooded areas with no underlying low-permeability sub-soil component, <br />Curve Number 66 <br />• Closure areas with no underlying low-permeability component, Curve Number 71. <br />• Existing grassed areas and revegetated ground with low-permeability sub-soils, <br />Curve Number 75 <br />• Rock Fill Slopes, Curve Number 50 <br />• Roads and compacted stockpiles with limited permeability, Curve Number 90. <br />Client:CC&V Gold Mining Co. <br />Title: Storm Water Management, MLE <br />4/11 /08 <br />Page 5 <br />