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-zs- 4) The Division's experience with underground mines in the Carbondale, Book Cliffs, Danforth Hills, and Yampa Coal Fields of the State, as well as in the Canon City area, indicates that mine inflows are not normally significant when ephemeral streams are undermined. Most of the streams to be undermined in the Canon City area are ephemeral and would not be expected to be significantly affected by mining. Flows in these ephemeral streams are concentrated in periods of snowmelt and high intensity precipitation events. The stream gradients are steep and their channels contain little alluvium. For the above reasons, very little surface water is retained long enough in the stream valleys to infiltrate into the ground water system. Therefore, the amount of water observed reaching the mine workings is insignificant. Perennial streams, however, may experience depletions of flow if mine workings are extended adjacent to and/or below the level of the stream valley (e.g., the bedrock alluvial contact). The lower stream gradient and the thicker alluvial deposits in perenniai stream valleys favor flow retention and recharge to the ground water systems. Due to the increased flow retention and ground water recharge in perenniai stream valleys, there is a greater potential for stream depletions by mining adjacent to or under these stream valleys. Amine in these areas could generate depletions by increasing mine inflows in the area. These mine inflows could be induced either through the mine workings encountering existing faults or fractures, or strata recharged by the stream, or through the mine producing subsidence fractures which extend to the stream valley bottom or to rock strata recharged by the stream. Only one mining operation, Dorchester No. 1, will undermine a perennial drainage, Newlin Creek. The quantity of flow may be depleted in Newlin Creek through the dewatering of subsidence induced faults or fractures and rock strata which are in direct or in indirect communication with the alluvium or stream bottom. The Division is currently reviewing the Dorchester No. 1 Nine permit application for compliance, and does not anticipate a significant impact to the hydrologic balance of Newlin Creek. In summary, it is unlikely that the current and proposed mining activities will significantly impact the natural Hydrologic balance beyond background levels produced by previous mining activities. C. Findings Pursuant to Rule 2.01.6(2)(c), the Division finds that, according to the information presented in the application and with the acceptance of stipulations contained in this document the proposed Twin Pines No. 2 mining operation has been designed to prevent material damage to the hydrologic balance outside the proposed permit area. IX. A 21(h Climatological information is presented on Pages JFSA 59 through 64 and pages 49-52 of the permit application.