1. Water Quality Control Commission June 8/9, 2015

2. In 2009, the Commission adopted a temporary modification for Segment 15 based on Water Effects Ratio (WER) copper values. WER-based copper standards were adopted for Segment 1a. The Commission determined that appropriate site-specific standards to protect aquatic life would be better resolved through BLM/FMB approach. Upper South Platte Segment 15 at 124th Avenue 2

3. Replace copper table value-based standards in Upper South Platte Segment 15 downstream of Hite facility outfalls plus Middle South Platte Segment 1a with BLM/FMB site-specific standards:  35.1  g/L acute  23.5  g/L chronic 3 South Platte River in Brighton, Upper South Platte Segment 15

4. Biweekly monitoring of 11 sites provided spatial coverage of both segments between 2009 and 2013. Monitoring data produced a robust dataset and are representative of a variety of flows and seasonal conditions. 4 Map of South Platte River indicating copper monitoring sites

5. BLM/FMB modeling for each monitoring station produced a set of protective acute and chronic copper values for each station. Statistical analyses showed that protective values were not significantly different among the 11 stations. The most protective acute and chronic values were selected to apply to both segments. 5 South Platte River south of Brighton, Upper South Platte Segment 15

6. 6 Metro will continue to collect all necessary data to develop the current proposed site-specific standards. Prior to every Regulation 38 review Metro will review and revaluate the chronic and acute copper criteria for each location. Should significant changes in the BLM/FMB-based copper standards be revealed, Metro will work with Division staff to propose appropriate protective changes to the site-specific copper standards.

7. Adopt site-specific copper standards for Upper South Platte Segment 15 below Metro outfalls plus Middle South Platte Segment 1a:  35.1  g/L acute  23.5  g/L chronic Metro will continue to monitor BLM/FMB parameters at stations throughout both segments and evaluate standards prior to every Regulation No. 38 review. 7 Hite Facility outfalls (upper left) on Segment 15