1. Cottonwood’s Proposed Site-Specific Selenium Standards in the Cherry Creek Basin Comments Presented by: Cherry Creek Basin Water Quality Authority Regulation #38 Presentation before the Water Quality Control Commission June 9, 2015

2. Protection of Water Quality and Beneficial Uses Paramount Best data and science essential. Encouraged with Cottonwood and WQCD recent proposed language: – No temporary modification request. – Seasonal selenium standards and TVS on lower reaches in proximity to Reservoir. – Assessment locations at upper and lower reaches in Windmill, Lone Tree and Cottonwood Creeks; water quality assessment criteria.

3. More Data Needed to Better Understand Aquatic Life Health and Potential Impacts Insufficient biological data provided. Selenium toxicity observed. Need to better understand potential biological impacts. Data and science key.

4. Biological Data Assessment Criteria Fundamental to Authority Support Value of gathering biological data and understanding current condition. – Documenting selenium levels in fish tissue and muscle. Understanding potential effects on all life stages – include larval stages.

5. Requested Decision Support Cottonwood and WQCD revised proposal contingent on including biological monitoring in assessment criteria. Desired Outcomes: Characterize chemical and biological conditions to demonstrate aquatic life use protection. Support ongoing communication and coordination between Authority, Cottonwood, and State Agencies.

6. Questions?