OPTIMAL RESERVOIR MANAGEMENT AND CROP PLANNING UNDER DETERMINISTIC AND STOCHASTIC INFLOWS1

ABSTRACT: This study analyzes planning under deterministic and stochastic inflows for the Mayurakshi project in India. Models are developed to indicate the optimal storage of reservoir water, the transfer of water to the producing regions, and the spillage of water from the reservoir, if needed. A deterministic programming model was first formulated to represent the existing situation. A chance-constrained model then was constructed to evaluate potential violations of the deterministic model. Both models were quantified for the command area. Data were collected from surveys of the area and from government agencies. Both the deterministic and change-constrained models suggest a more intensive cropping program in the region. Both emphasize more dependence on rabi and less on kharif crops. The chance-constrained especially suggests use of more water in the rabi season. Important chances in cropping programs and labor use take place under the chance-constrained model.     

ESTIMATED STREAM FLOW REQUIREMENTS FOR FISHES OF THE WASHITA RIVER BELOW FOSS RESERVOIR,WESTERN OKLAHOMA1

Velocity and depth preference curves for juvenile and adult red shiners (Notropis lutrensis) were developed for each season of the year. The incremental methodology, developed by the U.S. Fish and Wildlife Service for quantifying the amount of physical habitat available for fish, was applied as a basis for recommending minimum stream flows for life stages of red shiners and channel catfish (Ictalurus punctatus) in the Washita River below Foss Reservoir. The minimum stream flow required to support populations of red shiners and channel catfish was estimated to be 0.60 m³/s during all months except April and May, during which flushing flows of 3.0 m³/s were recommended. Under drought conditions a contingency flow of 0.18 m³/s was recommended for August through March, a flushing flow of 2.4 m³/s for April and May, and a flow of 0.30 m³/s for channel catfish spawning in June and July. Standing crop of adult red shiners per weighted usable area averaged 2.73 g/m² (27 kg/ha) for two sites on the Washita River. A positive relation between standing crop and weighted usable area was suggested. Use of the incremental methodology on the study reach below Foss Reservoir required 96 person-hours of labor, excluding training, travel, and developing preference curves, and a total cost of $1,762, of which $1,200 was for the purchase of equipment.     

COMPARISON OF TWO AUTOREGRESSIVE MODELS FOR MONTHLY STREAM FLOW GENERATION1

ABSTRACT: Two autoregressive models for monthly stream flow generation are compared based on the reproduction of the historical record in terms of several important statistics such as the mean, standard deviation, skewness coefficient, correlation coefficient, and the reservoir storage components. In the comparison, both theoretical considerations and practical applications are employed to evaluate the performance of each model.     

ESTIMATING THE SUSPENDED SEDIMENT LOAD IN RESERVOIRS1

ABSTRACT: The total suspended sediment loads of four north Mississippi reservoirs were determined from measurements of concentrations of suspended sediment in a vertical profile at several locations on each reservoir made during the year. These data were combined with the stage-height and known stage-volume relationships for each reservoir in a numerical integration to determine the total suspended sediment in the water body. Total suspended sediments were estimated using the product of the suspended sediment concentration in the surface water by the appropriate reservoir volume. The averaged ratios of the estimated to measured suspended sediment loads for each reservoir exceeded 0.90. Since the concentration of suspended sediments in surface waters of north Mississippi reservoirs has been shown as highly correlated with spectral reflectance, estimating the total suspended sediment of these reservoirs using remotely sensed spectral reflectance data is possible.     

DETERMINATION OF SEDIMENT YIELD BY TRANSFERRING RAINFALL DATA1

ABSTRACT: A methodology for obtaining the optimal design value to allow for sediment storage in a reservoir is presented for the situation where no data on sediment loads in the incoming streams are available. Information concerning the amount of sediment delivered to the reservoir over its life-time is obtained by a sediment yield model which uses data on rainfall amount and duration obtained from a nearby experimental watershed. Bayesian Decision Theory is used to obtain the optimal storage requirements in order to consider the natural variation of rainfall and the sampling error due to the short rainfall record available. The normally difficult calculations involved were made tractable by the use of simplifications and approximations valid in the context of the problem. Results show that sediment storage requirements can be calculated in this manner and that consideration of the uncertainties involved leads to a storage requirement substantially larger than that calculated without such consideration.     

RESERVOIR SEDIMENTATION1

ABSTRACT: Reservoirs, as well as lakes and estuaries, are subject to sediment accumulation. The rate at which sedimentation occurs is accelerated or diminished by man's activities. Acceptable rates of sedimentation are considered on the basis of costs of sediment storage and removal and a review of reservoirs constructed with sediment removal capabilities is given. The rates of reservoir sedimentation in the United States are summarized based on reliable data obtained from all sizes of reservoirs. Problems confronting the engineer concerning reservoir construction and maintenance are discussed on the basis of these data.     

RESERVOIR OPERATION THROUGH OBJECTIVE TRADE-OFFS1

ABSTRACT: Water resource development has progressed to the stage where various human factors are now being considered in reservoir design and operation. The introduction of human factor objectives complicates the problem since they are noncommensurate with other objectives and they are difficult to identify quantitatively. Some of the problems that now arise concern the proper methods for consideration of several different, sometimes subjectively identified, objectives in reservoir planning. The classical systems analysis approach to decision making for multiple objective problems is outlined and the inherent difficulties associated with multiple objectives and subjective estimates are identified. Techniques being used in reservoir design and operation are reviewed and discussed. An alternate technique for considering noncommensurate, subjectively identified, objectives, which relates the objectives in terms of real trade-off costs and eliminates the need for a priori estimates of objective worth is then presented. The method is illustrated with three examples, including a reservoir operation problem and a cooling tower design problem.     

松华坝饮用水源区补偿政策探讨

根据昆明政府颁布的《昆明市松华坝水源保护区生产生活补助办法(试行)》要求,在系统探讨了松华坝水源保护区实施补助的重要性和必要性的基础上,分析了办法实行可能产生的效果,并针对性地提出实施建议。     

三峡库区城镇建设用地驱动因子路径分析

随着三峡大坝的修建．三峡经济飞速发展．带动了利用三峡库区城镇建设用地的变化。本文以三峡库区21个县市1995—2005年城镇建设用用地的变化量为主要研究对象。结合1995-2005年期间第二产业与第三产业的集中指数与区位商的空间分布变化。采用路径分析建模的方法。奠立了城镇建设用地与固定资产投资、社会商品零售总额、第二产值、第三产值及城镇人口的路径模型．确定了备影响因子对蜮镇建设用地变化的影响程度。其中第二产值对城镇建设用地的变化影响最大．影响力最小的是城镇人口。此项研究进一步验证了路径分析模型在土地利用变化驱动力分析研究中的可行性．同时也为库区城镇建设用地的控制提供了参考。     

新疆某石化企业污水库周边土壤对钴的吸附行为研究

采用静态吸附法研究了新疆菜石化企业污水库周边土壤对重金属钴的吸附特征,考察了溶液pH值、钴离子平衡质量浓度、背景电解质浓度、吸附时间和环境温度等因素对钴吸附量的影响,并对吸附机理进行了初步探讨.结果表明:溶液pH值为1～4时,改变pH值对土壤吸附钴的影响显著;吸附时间在3h左右时钴吸附量趋于稳定;随溶液背景电解质浓度增大,土壤对钴的吸附量呈现先急剧后缓慢的下降趋势;土壤对钴的吸附量随温度升高而增加.拟合结果表明,Langmuir和Freundlich模型能较好地描述土壤对钴吸附的热力学过程;在3h内,土壤对钴吸附的动力学过程可以用一级反应动力学方程表示.方差分析结果表明,对土壤吸附钴量有显著性影响的因素有溶液pH值、钴离子平衡浓度、吸附时间和温度等.