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Adequacy Letter - TR 65 Page 3 September 17, 1993 pond model. MCC should reevaluate the model. 5. The watershed and pond model do not correspond for watersheds 18A, 18B, and 18C. The pond uses a curve number of 88 and the watersheds utilize a curve number of 82. The watershed runs should be changed to reflect the higher curve number. Ditches and culverts in this vicinity may need to be reviewed again. 6. The typical pond section on Drawing G-104 shows the sediment elevation level to be 6120.47, providing 1.32 acre-feet of storage, but the SEDCAD model shows the elevation to be 6102.07 with 1.20 acre-feet of storage. This should be reviewed and clarified. 7. According to Table 41 in MCC's permit, Summary of Water Rights, 10.05 acre-feet has been allowed to be stored in MB-2. However, the pond model utilizes 13.56-13.71 acre-feet for the permanent pool. If the permanent pool should only reflect the storage right, then the model should be revised. MB-3 Svstem Ditches• 1. There are no ditch designs for D3-2, D3-2A, D3-3, D3-4, and D3-4A. These should be provided to the Division. Culverts• 1. The nomograph for culvert C3-3 shows that the minimum culvert size should be 12 inches, but Table 44 lists an S inch culvert. The size of this culvert should be clarified. 2. There appears to be no culvert C3-1B on Map 54, but it is included on Table 44. If there is no C3-1B then it should be omitted from the table. 3. The size of culvert C3-2 should be increased as it accepts water from ditches D3-3 and D3-2, totalling 6.76 cfs. Pond• 1. What drainage area does the watershed run entitled "Coal Pile Drainage" include? How was this area, along with watershed 15D routed to the pond? 2. According to Table 41 in MCC's permit, Summary of Water Rights, 1.03 acre-feet has been allowed to be stored in MB-3. However, the pond model utilizes 1.30 acre-feet for the