Use Attainability Analysis (UAA)
Mining Remedial Recovery Company, Shasta County, California
 Remedial activities to improve water quality for water discharging from several mines located along West Squaw Creek in Shasta County have been ongoing for more than ten years. Activities include construction of surfacewater diversions, waste rock grading and consolidation, revegetation, installation of more than ten bulkhead seals, and construction of several passive treatment cells to address residual seepage. These activities have reduced point-source discharges of metals to West Squaw Creek by 96 percent, from 560 pounds per day to 20 pounds per day. Overall, point and nonpoint discharge has been reduced by 82 percent, from 720 pounds per day to 130 pounds per day. Even with these reductions, however, water quality at several locations continues to be in violation of the water-quality objectives identified in the Basin Plan. To address this issue, VESTRA is working with the Regional Water Quality Control Board (RWQCB) and Mining Remedial Recovery Company to approve a Use Attainability Analysis (UAA) and Basin Plan Amendment for West Squaw Creek. The UAA is a process included in the Clean Water Act (CWA) allowing an assessment of factors that affect the attainment of aquatic life uses or other beneficial uses to modify or remove designated beneficial uses. The objective of the West Squaw Creek UAA and Basin Plan Amendment is to modify the designated beneficial uses of warm and cold freshwater habitat to exclude fish and other metal or pH sensitive aquatic species and to remove designated but not existing beneficial use warm- and coldwater spawning in West Squaw Creek. The UAA and Basin Plan Amendment have been approved by the RWQCB and are scheduled to be considered by the State Water Resources Control Board. |
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