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Evapotranspiration studies for protective barriers: FY 1988 status report

Description: In FY 1988, evapotranspiration studies in support of the Protective Barrier Development Program focused on developing instruments to measure evapotranspiration and on conducting natural analog studies. This report describes a has exchange chamber being developed that will control internal temperature and relative humidity to simulate outdoor conditions. This device will measure evapotranspiration rates unambiguously from any surface and measure carbon dioxide exchange rates, which will provide information on plant growth processes. The report also describes ecophysiological experiments that were conducted to determine water and carbon dynamics of shrubs. 5 refs., 24 figs.
Date: May 1990
Creator: Link, S. O.; Thiede, M. E.; Evans, R. D.; Downs, J. L. & Waugh, W. J.
Partner: UNT Libraries Government Documents Department

Robustness of a multiple-use reservoir to seasonal runoff shifts associated with climate change

Description: Although much remains to be learned about long-term climate change associated with anthropogenic increases in concentrations of the so-called greenhouse gases,'' such as carbon dioxide and methane, there is a general consensus that some global warming will result from past and present emissions. In the western United States, the dominant hydrologic effect of such warming, aside from any accompanying changes in precipitation, would be to reduce winter snow accumulations in mountainous headwaters regions. To assess the robustness of reservoir operation to such shifts in seasonal runoff, simulations were developed of monthly runoff for the American River, Washington, using the National Weather Service River Forecast System. The American River is presently unregulated; however, we tested the performance of hypothetical reservoirs with capacity of 0.25 and 0.50 of the mean annual flow for a range of annual temperature changes from 0.0 (present climate) to 4.0{degree}C. We considered a multiple-purpose reservoir system operated for water supply ad hydropower, with minimum releases required for fisheries enhancement. In addition to evaluating the sensitivity of water supply, low flow, and hydropower performance using a heuristic operating rule, the relative performance of the system under present and altered climates was evaluated using an optimization algorithm, extended linear quadratic Gaussian control. This paper reports the results of hydrologic simulations for the American River, Washington. 13 refs., 8 figs.
Date: May 1, 1990
Creator: Lettenmaier, D.P.; Brettman, K.L. (Washington Univ., Seattle, WA (USA). Dept. of Civil Engineering) & Vail, L.W. (Pacific Northwest Lab., Richland, WA (USA))
Partner: UNT Libraries Government Documents Department

Evaluations of the effects of the Columbia River on the unconfined aquifer beneath the 1301-N Liquid Waste Disposal Facility

Description: Westinghouse Hanford Company (WHC) requested that Pacific Northwest Laboratory (PNL) perform a study to determine what influence the Columbia River has on the aquifer beneath the 1301-N Liquid Waste Disposal Facility (LWDF) located in the 100-N Area. Because of the change in operational status of the N Reactor to dry layup'' in November 1989, there has been a reduction in the liquid effluent discharge to the ground in the 100-N Area. This reduction in discharge reduces the artificial recharge to the unconfined aquifer, thereby altering ground-water flow in the vicinity of the 1301-N LWDF. This study addresses these changes and evaluates the effect that the Columbia River has on the unconfined aquifer beneath the 1301-N facility under present ground-water conditions. 30 refs., 8 figs., 4 tabs.
Date: May 1, 1990
Creator: Gilmore, T. J.; Borghese, J. V.; McDonald, J. P. & Newcomer, D. R.
Partner: UNT Libraries Government Documents Department