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12 <br />3.5 Arequa Gulch <br />Current Conditions <br />Main project area hydrologic conditions <br />The Arequa Gulch drainage and the MLE permit boundary are shown on Figure 3.1. <br />Arequa-Gulch is asouthwest-oriented, ephemeral drainage that crosses the diatreme- <br />granite boundary. Arequa Gulch drains into Cripple Creek approximately one mile west <br />of where Highway 67 crosses the drainage. Historical mine features in Arequa Gulch <br />include: the Prince Albert Tunnel and associated development rock, and relocated <br />tailings from the historic Carlton Mill. <br />The Cresson Project disturbance in the drainage consists of the VLF and associated <br />facilities, Arequa Gulch Overburden Storage Area, and the Adsorption-Desorption <br />Recovery Facility (ADR). Material placement on the VLF will continue though <br />approximately 2016 under the MLE. The MLE will extend the VLF to the east. The <br />current limits of VLF and the proposed extension are shown on Figure 1.2. <br />Surface Water <br />Surface water conditions in Arequa Gulch are monitored at two locations between the <br />VLF and the confluence of Arequa Gulch with Cripple Creek. The sample station <br />designations are: AG-1.5 and AG-02. Sample stations are shown on Figure 3.1. The <br />period of record, water quality statistics, stream flow data and field parameter data <br />summaries have been compiled for the sample stations AG-1.5 and AG-02 and are <br />provided in Tables A5 and A6 (Attachment A), respectively. <br />Surface water flows in Arequa Gulch are seasonal and range from dry to 700 gpm. <br />Flows, if observed, occur in the spring due to snowmelt runoff, and/or in the summer due <br />to seasonal rains and runoff. Average flow rates increase downstream from 19 gpm to <br />39 gpm for AG-1.5 and AG-02, respectively. <br />Surface water in Arequa Gulch is characterized as calcium-sulfate type. A piper plol <br />(Figure 3.3) shows the major ion water chemistry for the Arequa Gulch surface water <br />stations. Data in Tables A5 and A6 (Attachment A) show that average pH values <br />increase downstream from 6.0 su at AG-1.5 to 7.3 su at AG-02. Average nitrate values <br />range from 4.8 mg/L to 13.4 mg/L. Average sulfate values are 665 mg/L at AG-1.5, and <br />626 mg/L at AG-02. <br />Groundwater <br />Groundwater data in Arequa Gulch are collected from three monitoring wells: ESPMW-1, <br />CRMW-3A, and CRMW-36. CRMW-3A is completed in the alluvium; ESPMW-1 and <br />CRMW-3B are completed in the granite. The locations of wells are shown on Figure 3.1. <br />Five monitoring wells have been plugged and abandoned in Arequa Gulch due to the <br />development and prior expansion of the Cresson Project. These monitoring wells were <br />designated CRMW-1A, CRMW-2A, CRMW-2B, CRMW-4A, and CRMW-46. The period <br />of record, water quality statistics, water level and field parameter data summaries have <br />been compiled for monitoring wells CRMW-3A, CRMW-36 and ESPMW-1, and are <br />provided in Tables A7 through A9 (Attachment A), respectively. <br />2736 Cripple Creek & Victor Gold Mining Company <br />Water Management Consultants <br />