City of Greeley Prepared for the Water Quality Control Commission IN THE MATTER OF THE ADOPTION OF REVISIONS TO THE CACHE LA POUDRE SEGMENT 12 IN THE CLASSIFICATIONS AND NUMERIC STANDARDS FOR THE SOUTH PLATTE RIVER BASIN, LARAMIE RIVER BASIN, REPUBLICAN RIVER BASIN, SMOKY HILL RIVER BASIN, REGULATION #38 (5ccr 1002-38) Prepared for the Water Quality Control Commission June 2015

Summary of Temperature Issues Greeley proposes a temporary modification to the temperature standards on Segment 12 of the Cache la Poudre River with the following terms: Daily maximum temperature (DM) = current condition Weekly average temperature (WAT) = current condition Compliance issues Demonstrated/predicted compliance issue, as evidenced by five years of effluent, upstream and downstream temperature data Significant uncertainty regarding the extent to which existing quality is the result of natural or irreversible human-induced conditions, as demonstrated by upstream summer temperatures City of Greeley

Temperature Data Collection and Assessment City of Greeley

Compliance Issue City of Greeley

Plan to Resolve Uncertainty Temperature Data Collection and Assessment Collect additional temperature data for Segment 12 at additional locations upstream of discharge point Investigate cause of upstream temperature exceedances to determine if an ambient based site-specific standard is appropriate Aquatic Life Data Acquire fish and macroinvertebrate data in Segment 12 to determine if recalculation is appropriate Evaluate for evidence of a balanced, indigenous aquatic life population Feasibility Studies Evaluate the technological, economic, and environmental feasibility of alternate temperature management strategies. Regulatory Involvement Continue to participate in the Basic Standards Workgroup and the Permit Issues Forum’s discussions of temperature standards City of Greeley

Summary A temperature temporary modification is appropriate based on demonstrated/predicted temperature issues An expiration date of 12/31/2020 is appropriate to allow time to resolve uncertainty in Segment 12, both upstream (Fort Collins) and downstream (Greeley). Due to winter issues upstream and summer issues downstream, a year-round temporary modification of current condition for temperature in Segment 12 is appropriate. City of Greeley