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causing the face to become steep and could lead to a failure of the dam. The State Engineer has <br />talked with the Company and expressed a need to repair the riprap and flatten the upstream slope <br />of the dam. <br />Lake Isabelle <br />Lake Isabelle is the highest elevation reservoir in the Left Hand Ditch system, and is located in <br />the Indian Peaks Wilderness Area at an elevation of about 11,000 feet. A hard rock tunnel is <br />used to divert water through the mountainside to an outlet work. At full storage Lake Isabelle <br />stores 550 acre -feet of water. <br />Lake Isabelle is typically operated by manually opening the gate valve which releases water for <br />agricultural uses in midsummer. The gate valve is closed at the end of the summer to allow the <br />lake (reservoir) to refill. The Company has found that the gate valve controlling the flow of water <br />from Lake Isabelle cannot be reliably operated from the control building. This unreliability <br />forces them to operate the valve from the bottom of the shaft. When operating the valve from the <br />bottom of the shaft, someone must climb down the shaft (approximately 45 feet) using a series of <br />wooden platforms and ladders to reach the valve. Confined space protocols, as prescribed by the <br />Occupational Safety and Health Administration (OSHA), must be followed in order to enter the <br />shaft to control the gate valve. These protocols include but are not limited to air quality <br />monitoring and emergency rescue (extrication) equipment to be available and ready for use. <br />Currently the shaft has several wood platforms and wood ladders that are used to reach the gate <br />valve. These platforms and ladders have decayed and are slippery from the near constant <br />exposure to moist air. LDC has found that the current platforms and ladders need to be replaced <br />to ensure their safety and reliability. The platforms and ladders may be replaced with aluminum <br />to reduce the amount of decay and extend their life expectancy, but other materials could be used. <br />OSHA confined space protocols are still required when entering the shaft. <br />An inspection of the shaft, outlet pipe, outlet tunnel, and gate in 2011 revealed the following <br />deficiencies: <br />1) The outlet pipe has hole in the invert of the downstream pipe, this appears to have been <br />caused by cavitation and erosion from normal operations. Moisture levels in the shaft <br />indicate water may be leaking from the pipe and ponding in the shaft during operations. <br />2) Access to the gate building is up a steep rock face that may require the construction of a <br />landing and ladder to meet the current OSHA requirements. This concept is expected to <br />be difficult to obtain approval by the USFS. <br />3) The shaft twists and turns in the vertical access, thus requiring multiple landings. <br />4) The outlet tunnel empties into a 36 inch pipe that is buried under five feet of rock on <br />average, the rock will need to be removed by hand due to the location of the dam in the <br />wilderness area. <br />5) The outlet pipe downstream of and connected to the existing gate and the outlet pipe at the <br />downstream end of the tunnel do not appear to be in alignment. This will require special <br />consideration when if a new pipe is installed from the existing gate to the discharge end of <br />the tunnel. <br />Allen Lake and Lake Isabelle — 12.012 <br />Left Hand Ditch Company Page 9 <br />