M EMORANDUM O CTOBER 5, 201 7

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1 M EMORANDUM O CTOBER 5, TO: FROM: SUBJECT: BOARD OF DIRECTORS ERIC KUHN, GENERAL MANAGER PETER FLEMING, ESQ. GENERAL COUNSEL RAY TENNEY, P.E., DON MEYER, P.E. WOLFORD MOUNTAIN RESERVOIR AND ELKHEAD RESERVOIR OPERATIONS This memo summarizes 2017 Wolford and Elkhead Reservoir operations and maintenance activities. No Board action is required. Wolford Reservoir Operations The graph below shows 2017 Wolford operations, including fill on May 14 th, the release of 600 cfs

2 Page 2 of 5 10/05/2017 in early June to benefit the Endangered Fish in the Grand Valley during peak runoff, and the release of all 6,000 acre feet from the permanent Fish pool in August and September to benefit the Endangered Fish during base flows. The Shoshone Power Plant Call came on August 22 nd and on August 31 st the Cameo Call came on. On September 1 st the Shoshone Power Plant was taken offline to inspect the tunnel and perform work on the tunnel headgate. During this 15 day outage the Cameo Call remained in effect, negating the need for Shoshone Outage Protocol (ShOP) operations. Maintenance Activities at Wolford Mountain Reservoir Crest Rehabilitation and Monitoring Peninsula Removal The crest rehabilitation project, designed in-house to restore freeboard lost to crest settlement, is awaiting approvals from the US Army Corps of Engineers and the Colorado State Engineer Dam Safety Branch. Removal of the shale peninsulas, constructed in 2012 to monitor the behavior of the upstream shell during drawdown, is included in this project. This work has been postponed until Muddy Creek Stream Maintenance 2017 Work Maintenance work on the mitigation area so far this year has been limited to dredging of accumulated sediment at the Schwab Ditch headgate structure to improve diversions, and Schwab Ditch culvert maintenance. Refurbishing of the Tyler Tailwater Ditch structure will be done in late October. Replacement of the Schwab Ditch headgate and work on the Schwab Ditch wasteway headwall and headgate have been postponed until next year. CH2M Hill (Susan Hall) is assessing the overall condition of the wetlands and USACE permit status. Based on her field inspection Susan is encouraged by the overall conditions of the wetlands. Ritschard Dam Deformation Investigation The embankment continues to deform at established rates as expected, with monthly monitoring and reporting to the State under conditional full storage status. AECOM has finalized the investigation report supporting the decision to return to normal operations with the long term monitoring plan in place.

3 Page 3 of 5 10/05/2017 Outlet Works Maintenance Activities In July we reported to the Board that District Staff had experienced difficulty opening and closing the main 96-inch gate at Wolford and that leakage greater than previously experienced was observed. Underwater camera inspection by District Staff using a weighted GoPro showed the bronze seals in the edges of the gate frame had been displaced and that a few of the stem guides had also been displaced, see photo below. In June Marine Diving Services (MDS) was employed to realign the displaced stem guides. Realigning the stem guides allowed the wedges to fully seat and reduced the amount of leakage, but not to a sufficient degree. In August the River District contracted MDS again to inspect the main gate seals and to seal the gate. MDS observed that much of the bronze seal was missing or damaged. MDS then sealed the main gate, reducing the leakage to an acceptable amount. Temporary sealing of the main gate will allow access to the conduit for inspection and maintenance of the guard gate and the 96 inch butterfly valve. Options to replace the main gate are under development. These activities will be scheduled for spring of 2018 when the reservoir is spilling, to maintain flow in Muddy Creek while the outlet works is out of service. Recreation Area Management The agreement with our recreation area concessionaire Red Mountain RV Park (CA15032) was modified in early 2017 to focus only on recreation area management, and was recently extended to October 31, The assistance with dam operations previously provided by Red Mountain RV was brought in house with the hiring of another full time operator, Jack DeSanti. Staff reports that Jack is responsible and a quick learner. Recreation area use has been very high this season with several dates completely sold out. Camping in the mitigation area has increased recently with noticeable impacts. Staff (John Currier) is planning to meet with BLM to discuss recreation management issues in the near future.

4 Page 4 of 5 10/05/2017 Elkhead Reservoir Operations Below is a graph of 2017 Elkhead Reservoir Operations. The reservoir began spilling March 27 th while releasing 70 cfs through the outlet works. Releases from the 5,000 acre feet Recovery Program pool began August 25 th. Recent increases in Yampa River flows due to a series of rain events prompted the USFWS to terminate these releases on October 2 nd, leaving 827 acre feet in the pool. Additional Elkhead Fish pool releases are unlikely. Maintenance Activities at Elkhead Reservoir Elkhead Outlet Works Repairs The presence of the spillway fish barrier net this spring allowed the outlet works to be taken out of service. During spill the 42-inch fixed cone valve was removed, refurbished, reinstalled and returned to service, and refurbished guides for the 5 gate stems and the fish screen stem were replaced with proper anchor bolts by Inland Potable Services. However, inspection by River District Staff last week using the weighted GoPro camera revealed that one of the fish screen stem guides had been pulled from the tower wall, see photos below. Staff will update the Board October 18 th on plans for remedial action.

5 Page 5 of 5 10/05/2017 Elkhead Spillway Fish Barrier Net The spillway fish barrier net and debris barrier appear to have performed well. The first annual dive inspection of the net was performed in late July. Early Colorado Parks and Wildlife assessments show no fish downstream.