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外文期刊>Canadian water resources journal
>COMPARISON OF RESERVOIRS WITH DISSIMILAR SELECTIVE WITHDRAWAL CAPABILITIES: EFFECTS ON RESERVOIR LIMNOLOGY AND RELEASE WATER QUALITY
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COMPARISON OF RESERVOIRS WITH DISSIMILAR SELECTIVE WITHDRAWAL CAPABILITIES: EFFECTS ON RESERVOIR LIMNOLOGY AND RELEASE WATER QUALITY
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机译：COMPARISON OF RESERVOIRS WITH DISSIMILAR SELECTIVE WITHDRAWAL CAPABILITIES: EFFECTS ON RESERVOIR LIMNOLOGY AND RELEASE WATER QUALITY
Between 1970 and 1980, studies were conducted on several Corps of Engineers impoundments in Oregon, U.S.A., to determine the effects of radically different outlet structures on reservoir limnology and release water quality.The 13 dams in the Willamette River Basin provide only limited capability for selective water withdrawal. Most of the projects (12) have outlets positioned at only one or two elevations, with two-level outlets spaced close together vertically at some dams. This has contributed to water quality problems in reservoirs and downstream, as exemplified by Hills Creek Project which traps highly turbid flood flows below the two outlets positioned 7#x2002;m apart near the center of the vertical axis of the dam. As a consequence, downstream release flows remain turbid for months and years thereafter. Additionally autumn drawdown for flood control storage gradually lowers the photic zone into the depth of withdrawal, sending summer accumulations of phytoplankton, organic detritus and nutrients toward downstream impoundments.In contrast, Lost Creek Dam on the Rogue River employs a 78#x2002;m-tall free-standing intake tower, with intake ports at four widely-spaced elevations (i.e., 563, 546, 527 and 500#x2002;m, above msl) and a 4#x2002;m-diameter turbidity conduit extending 120#x2002;m into the reservoir to draw near-bottom water at elevation 486#x2002;m. This makes it possible to purge turbid inflows and to selectively draw water from one or more levels for thermal optimization downstream. But conflicts in reservoir operations have developed, such as the unintentional releases of H2S-contaminated hypolimnetic water through the turbidity conduit in 1977. These problems are usually resolved, however, by temporarily discharging water drawn from higher elevations in the reservoir, or from depths which will have the least impact on downstream water resources.
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