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251.
M. Hossein Sabet James Q. Coe 《Journal of the American Water Resources Association》1986,22(4):587-596
ABSTRACT: A large-scale simulation/optimization model provides schedules for operation of water and power for the California State Water Project (SWP). The SWP consists of a series of reservoirs linked by rivers, pumping plants, canals, tunnels, and generating plants and is operated by the California Department of Water Resources. The Department provides water to municipal and agricultural users, and manages its electrical loads and resources. The model, therefore, performs hydraulic and electrical computations leading to optimal operation of the entire system. It consists of hydraulic network programming components to meet the storage objectives at all the reservoirs, a linear programming component to determine the schedules at pumping and generating plants, an electrical network programming component to balance electrical loads and resources, and a number of other simulation components. It operates on yearly, weekly, and daily bases. It is primarily used for real-time operation of the SWP and can provide hourly detail schedules which are implemented by the SWP staff via a computerized system. 相似文献
252.
The paper examines characteristics of science parks in the face of employment decline, raising doubts about the scale of their success. The paper re‐examines previous research on the existence and causes of long waves of economic growth and decline and concludes that if these are not generated by innovations in production, then it should not be surprising that science parks have not lived up to expectations. 相似文献
253.
Paul N. Wilson Teddy J. Goldammer James C. Wade 《Journal of the American Water Resources Association》1988,24(1):1-9
ABSTRACT: Urban wastewater can be a valuable source of water and plant nutrients for agricultural producers, particularly in arid regions. The scientific literature reveals cautious optimism concerning the biological, institutional, and economic viability of irrigating crops with secondary-treated effluent. A derived effluent demand function for agricultural producers near Tucson, Arizona, reveals a potential annual demand of 11,000 acre-feet under present price and proposed delivery system conditions. In this case, wastewater could be exchanged for ground water and both the urban and rural areas would gain. 相似文献
254.
255.
James A. Kushlan 《Environmental management》1983,7(3):201-207
An important aspect of developing a philosophical foundation for management of reserves using an ecosystem approach is the exploration of the relationship of ecosystem management strategies to the need for conservation of species of special concern Colonial water birds are species that may deserve special consideration They occur in over 25 US national parks, but in no case do the parks have a monopoly on the total protection or management of these birds As an agency responsible for such populations, the National Park Service engages in activities such as inventory, monitoring, research, and management, using an ecosystem management philosophy Most parks contain only segments of natural ecosystems, and management actions, even those undertaken from an ecosystem perspective, may not be in the best interest of an individual species Management strategies for widely ranging special species require a regional perspective, including plans that take into consideration the differing objectives of the agencies responsible for such species A matrix of the different management strategies in various areas may provide a suitable, perhaps the best, method for protecting special species In practice, any one strategy, such as management of remnant ecosystem patches or intensive single-species management, may not be successful alone 相似文献
256.
Stanley L. Ponce James R. Meiman 《Journal of the American Water Resources Association》1983,19(3):415-419
The demand for more water is increasing throughout the country. Research on upland watersheds clearly demonstrates that water yield can be increased using forest and range management practices. Based on the experience of the past several decades and a review of six papers in a recent AWRA series on water yield augmentation through vegetation management, the following issues and concerns are discussed: predicting increased yields from large basins; economic evaluation of additional flows; court acceptance and need for system models; the legal question of ownership and transferability of increased yields; and management emphasis on private and federal lands. The immediate potential for water yield augmentation is on carefully selected watersheds that have the bio-physical potential to produce high value water under environmentally acceptable multiple use management. We predict water yield management on a broader scale will result from increased pressures to solve the legal and economic issues involved. 相似文献
257.
Puneet Srivastava James N. McNair Thomas E. Johnson 《Journal of the American Water Resources Association》2006,42(3):545-563
ABSTRACT: The performance of the Soil and Water Assessment Tool (SWAT) and artificial neural network (ANN) models in simulating hydrologic response was assessed in an agricultural watershed in southeastern Pennsylvania. All of the performance evaluation measures including Nash‐Sutcliffe coefficient of efficiency (E) and coefficient of determination (R2) suggest that the ANN monthly predictions were closer to the observed flows than the monthly predictions from the SWAT model. More specifically, monthly streamflow E and R2 were 0.54 and 0.57, respectively, for the SWAT model calibration period, and 0.71 and 0.75, respectively, for the ANN model training period. For the validation period, these values were ?0.17 and 0.34 for the SWAT and 0.43 and 0.45 for the ANN model. SWAT model performance was affected by snowmelt events during winter months and by the model's inability to adequately simulate base flows. Even though this and other studies using ANN models suggest that these models provide a viable alternative approach for hydrologic and water quality modeling, ANN models in their current form are not spatially distributed watershed modeling systems. However, considering the promising performance of the simple ANN model, this study suggests that the ANN approach warrants further development to explicitly address the spatial distribution of hydrologic/water quality processes within watersheds. 相似文献
258.
M.S. Bedinger James R. Harrill 《Journal of the American Water Resources Association》2006,42(4):827-839
ABSTRACT: Devils Hole is a collapse depression connected to the regional carbonate aquifer of the Death Valley ground water flow system. Devils Hole pool is home to an endangered pupfish that was threatened when irrigation pumping in nearby Ash Meadows lowered the pool stage in the 1960s. Pumping at Ash Meadows ultimately ceased, and the stage recovered until 1988, when it began to decline, a trend that continued until at least 2004. Regional ground water pumping and changes in recharge are considered the principal potential stresses causing long term stage changes. A regression was found between pumpage and Devils Hole water levels. Though precipitation in distant mountain ranges is the source of recharge to the flow system, the stage of Devils Hole shows small change in stage from 1937 to 1963, a period during which ground water withdrawals were small and the major stress on stage would have been recharge. Multiple regression analyses, made by including the cumulative departure from normal precipitation with pumpage as independent variables, did not improve the regression. Drawdown at Devils Hole was calculated by the Theis Equation for nearby pumping centers to incorporate time delay and drawdown attenuation. The Theis drawdowns were used as surrogates for pumpage in multiple regression analyses. The model coefficient for the regression, R2= 0.982, indicated that changes in Devils Hole were largely due to effects of pumping at Ash Meadows, Amargosa Desert, and Army 1. 相似文献
259.
Over the last several years, the inhalation of decay products coming from radon-222 has become a national health concern.
It is estimated that somewhere between 16,000 and 20,000 people die annually in the United States from lung cancer due to
exposure to these decay products. Nationwide, 95% of all homes have not been tested for radon, and so it would seem that any
methodology that could give a general idea of indoor radon concentrations (without actually testing the house itself) might
be useful. While not intended to replace a radon test, which is both simple and inexpensive, our project attempts to predict
indoor radon concentrations based on easily obtainable information from Soil Conservation Service county soil surveys and
US Geological Survey surficial geology maps. We have chosen four parameters: soil permeability, surficial geology, soil shrink-swell
potential, and distance to the nearest geologic fault. Of these four variables, surficial geology and distance to fault correlated
well to winter indoor radon concentrations as measured by short-term (48-h) tests. While it is understood that there are limits
to this methodology, primarily because of map scale problems, the correlations mentioned above were very strong and suggest
further study would be useful. 相似文献
260.
James P. Pastorick 《补救:环境净化治理成本、技术与工艺杂志》1993,3(2):221-231
To date, most of the development of unexploded ordnance (UXO)-related requirements and procedures have been accomplished by the U.S. Army Corps of Engineers and the U.S. Army Toxic and Hazardous Materials Agency. The U.S. Navy and U.S. Air Force also have a significant requirement for environmentally related UXO expertise. This article traces the evolution of the UXO field, as developed by small businesses and the various branches of the U.S. Army, and describes the implications of conducting an environmental investigation or remediation in an area contaminated, or suspected to be contaminated, with UXO. Lastly, the basic procedures and the tools and equipment used to accomplish UXO decontamination are described to inform field managers of the impact that UXO hazards can have on their overall project. 相似文献