Permitting requirements stipulate that Pacific Power can draw down water levels no faster than a rate of 2 inches per hour, which, according to Gravely, should help reduce negative environmental effects downstream. (Flows downstream of the dam will increase as water is drained from the pond.) Gravely expects the draw down to take a couple days, while the actual inspection, he said, should take no more than one day.
Water levels in Mirror Pond are already lower than normal—at least two feet lower—having fallen victim to a double whammy: the leak in the 103-year-old dam and the reduced upstream flows typical of fall and winter, the traditional end of the irrigation season. This October, however and with Wickiup Reservoir levels low following a warm, dry spring and summer, Oregon's Water Resources Department chose to release only 32 cubic feet per second from the reservoir, a decision which led to the deaths of approximately 3,000 fish. Last winter the state agency was releasing approximately 300 cfs. Wickiup Reservoir and various tributaries supply the Deschutes River with its water. Draining Mirror Pond further is not expected to further jeopardize fish populations, though more fish species may yet suffer as a result of the minimal upstream flows.