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CHAPTERFOUR <br />Enuironmenisl I~onsequences <br />subject to the applicable Conditions of Approval outlined in the BLM RMP (BLM 1997) to help <br />mitigate potential impacts from surface disturbing activities. <br />4.3.2 Direct and Indirect Impacts <br />4.3.2.1 Proposed Action <br />Piceance Site <br />Exposure and compaction of the soil surface during project construction could increase water <br />yield and stream flow and degrade water quality in the short term. Any increase in quantity of <br />stream flow due to disturbance would be negligible due to the relatively small az~;a affected at <br />any given time and the lack of any perennial streams across the site. Intermittent channels <br />traverse the Piceance Site and generally carry water only after precipitation events and during <br />snowmelt. The initial processing plant would be located approximately 0.5 mile from any <br />identified drainages. The 5-year mine panels would intersect with the intermittent channels <br />tributary to the Piceance Creek. Most of the activities within the mine panels aze located on level <br />plateaus outside of natural gullies and drainages. Prevention of impacts to surface drainages due <br />to excessive runoff from well pads and other well field features would be accomplished by <br />employing Best Management Practices (BMPs) for erosion control (Appendix Al. All disturbed <br />sites would be stabilized using interim revegetation and mulching methods to prevent erosion. <br />A portion of the surface runoff from the 6.5-acre initial processing facility azea would be diverted <br />to an evaporation pond located to the west of the mine panels on plateau. The remaining runoff <br />would be handled according to BMPs identified in the facility's state Stormwater Discharge <br />Permit and Stormwater Management Plan. Surface water quality could possibly be affected <br />should the evaporation pond accidentally leak or overlow and discharge to an intermittent <br />drainage. As described in Section 2.2.1.2, the 13-acre evaporation pond would be designed with <br />a dual liner and leak detection system. The pond beans would be designed with atdequate storage <br />to contain the 100-yeaz, 24-hour storm event and at least 1 foot of freeboazd to accommodate any <br />wave action. The pond would be monitored daily for potential overflow. Overto}~ping of the <br />berm is unlikely. <br />Pipelines and roads, as lineaz facilities, would traverse the intermittent drainage channels where <br />avoidance of such crossings would not be feasible. Several miles of intermittent Fictive channels <br />tributary to Piceance Creek were identified as waters of the US (Steigers 1998b). If any drainage <br />crossings are necessary, the crossings would be accomplished using appropriate EtMPs and BLM <br />Conditions of Approval to minimize impacts and restore the drainage to its appro:Kimate original <br />condition. All crossings of the intermittent channels would require authorization from the COE <br />through the CWA Section 404 permitting process. Therefore, no significant impacts would <br />likely occur to surface water quality due to constructing roads and pipelines across drainage <br />channels. <br />Hydrostatic test water for the natural gas pipelines (Alternatives A and B) would be handled in a <br />manner that would not adversely affect soils, stream channels, or surface water. \Vater quality <br />testing would be conducted both before and after the test to confirm that test water to be <br />4-] 0 Surface Water and Surace Water Drainages <br />