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Carol Pahlke December 23, 1980 Page 6 Revised Maps: Revised Map mitted to MLRD and OSM as 1980 response of Kerr Coal 1980 Adequacy Review. 37a was previously sub- part of the December 4, to the MLRD November 6, Section 780.25 - Reclamation Plan: Ponds, Impoundments, Banks, Dams and Embankments Kerr has responded to OSM and MLRD's concern over how water will be routed through Pond E and F. We are not satisfied with the water being discharged from Pond F through the road. The road culvert was designed using AMC-II condition with a design flow of 51 cfs with a HW/D of one foot. Water discharged from Pond F as the result of a 25 year storm will cause a HW of 13.6 feet as shown in Exhibit 42. Kerr should indicate whether this will result in a flow over the road and discuss the potential for adverse effects on the stability of this road. Backup data should be included in the response. Response: The road culvert under County Road 12E was designed for AMC-III condition, rather than AMC-II condition as stated above. The minimum road elevation in the vicinity of Pond F is approximately 8151.8+. In its December 4, 1980 response to the November 6, 1980 Adequacy Review of MLRD, Kerr Coal submitted, as revisions to Exhibit 42, additional backup data prepared by Leonard Rice Consulting Water Engineers, Inc. ("LRCWE") in con- nection with the interaction of the Pond F spillway in County Road 12E. Specifically, Kerr Coal sub- mitted a document entitled "Effect of County Road on Spillway Operation, Pond F" dated November 11, 1980, by D.E.B., Sheet 2 of 2. This document gives the elevation of the spillway for Pond F, the eleva- tion of the designed water surface depth over the spillway, the ponding depth for the pooled water behind County Road 12E and the road cross-section. Ponding elevation is approximately 8151.6 feet, and difference in surface water elevation is 0.2 feet. Although not a great deal of freeboard, this would indicate no road overtopping or any attendant road stability concerns under a worst case scenario.