Laserfiche WebLink
Interoffice Memorandum <br />To: Zach Trujillo <br />From: Rob Zuber f ?� <br />Subject: New Elk —TR -64 Review— Ditches and containment structure <br />Date: 5/17/2012 <br />Zach — <br />Regarding the TR -64 submittal, I have reviewed NECC's plans for upland diversion ditches, culverts, and Containment <br />Area #3, including the SEDCAD modeling inputs and output. <br />The designs and calculations looked good except for the following comments (directed to NECC so you can easily copy <br />into your adequacy review letter): <br />• Ditch D26 flows into ditch D58. Please explain how this is accounted for in the design. <br />• A drainage reaches the valley floor approximately 80 feet west of the proposed Bates Shaft in close proximity to <br />the point where ditches D59 and D60 both begin (the upgradient ends). Please explain how the flow down this <br />drainage will be directed to D60 rather than D59. (Based on areas in the SEDCAD model, it is apparent that D60 <br />receives these flows.) <br />• Please revise Table 20, Ditch Data. Some of the values for ditch D59 appear to be incorrect including the peak <br />discharge and the ditch slope; they do not match the values in the SEDCAD printouts. Also, the page number for <br />this table may be incorrect. Should it be 2.05 -11b? Revision of this page must be coordinated with possible <br />revision of the same page due to TR -65. <br />• In Table 21, culverts C79 and C80 are listed as having a minimum diameter of 36 inches. A field inspection from <br />early May 2012 reveals that C79 will need to be replaced to meet this requirement. If this project is <br />constructed, please make sure this replacement is performed. <br />• A mistake was detected on page EXH 19(21) -2. The units for the three year sediment volume should be acre- <br />feet, not cubic feet. <br />If you have any questions or would like me to look at any additional items regarding TR -64, please let me know. <br />Thanks, <br />Rob <br />