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... " '''1 n UUjJ 3. Howard Coombs, University of Washington, geotechnology and seismic studies. The stability study was furnished the panel of experts in a meeting on December 5, 1977. Other data furnished them by both the Lower Missouri Region and the E&R Center, as well as a list of the December meeting attendees and an agenda, are appended to this report. On December 6, 1977, the experts were taken to the proposed Narrows Dam and Reservoir sites. The sites were viewed from the air and afterward various points of interest were examined on the ground. The three panel members, who completed the independent safety review in January 1978, concluded that a safe dam can be constructed at the Narrows site using state-of-the-art techniques. The panel members pOinted out that extremely conservative assumptions were used in the Bureau's foundation seepage analysis which may have led to overly conservative conclusions concerning foundation seepage problems. A summary of the panel's oral briefing on the results of their studies is appended. In addition, letters from individual panel members are appended, which confirm that a safe dam can be constructed and that the panel members are in agreement on the findings. The firm of Woodward-Clyde, Consulting Engineers, under contract to the Colorado Water Conservation Board, is. conducting a parallel review of the safety and seepage problems. Reservoir Seepage ---- -Bacl<groun<f . -- - --- The Geological Survey was requested to study the potential seepage from Narrows Reservoir and its effect on the ground-water aquifer. A steady- state analysis was completed and is described in a May 1976 report titled, "Simulated Effects of the Proposed Narrows Reservoir on the Water-Table Aquifer Along the South Platte River, Morgan County, Colorado." Further study using a transient analysis model is presently underway. Results of "Steady-State" Analysis The following is an abstract from the May 1976 "Steady-State" report: 11