CHANGES IN PHYSICAL AND CHEMICAL VARIABLES IN A NEW RESERVOIR DUE TO PUMPED STORAGE OPERATIONS1

ABSTRACT: Information on biologically important physical and chemical variables is presented for Lake Oconee, a newly impounded pumped storage reservoir in Georgia. During its first summer, when no pumping occurred, temperature, oxygen, pH, inorganic nitrogen, and phosphorus were vertically stratified with severe hypolimnetic oxygen depletion. During the second summer, when pumped storage was in operation, more homogenous vertical profiles, generally higher oxygen, and lower dissolved nutrient concentrations were observed. These pumped storage effects were observed at all stations, rather than being confined to the immediate vicinity of the dam.     

GEOMETRIC VARIATIONS IN RESERVOIR WATER QUALITY1

ABSTRACT: In developing water quality models for lakes and reservoirs, the assumptions of one-dimensionality (i.e., water quality changes are significant only in one dimension – usually depth), as well as two-dimensionality (considering the length and depth of the water body), have been utilized to predict water quality. In both caws, the assumption of lateral homogeneity is made. A field study was undertaken to determine the change of water quality in the lateral dimension. The main study reservoir was Center Hill Lake in Middle Tennessee. Data were also obtained for Cherokee Lake in East Tennessee. Several water quality parameters (temperature, dissolved oxygen, pH, conductivity, and oxidation reduction potential) were analyzed over the length, breadth, and depth of these reservoirs from pre-stratification through post-stratification. The statistical and theoretical three-dimensional analysis showed the expected variation for each water quality parameter in each direction. The influence of the lateral dimension on water quality management and modeling was found to be negligible.     

Evaluation of a System to Automatically Sample Zooplankton From the Discharge of Dams1

ABSTRACT: Automatic plankton samplers installed at two dams on the Connecticut River Continuously monitored crustacean zooplankton from October 1977 through 1979 and allowed a significant reduction in man-hours involved in an extensive sampling program. Automatic samplers efficiently sampled most species and size classes of crustacean zooplankton in a similar, but not consistently identical manner as a commonly used towed-net plankton sampler. The smallest sized zooplankton were captured more efficiently than the largest. Mesh selection and sampler avoidance exerted different influences on automatic samplers and towed nets. Future use of the samplers and direct comparison of results to results obtained by other methods was supported.     

STOCHASTIC DYNAMIC PROGRAMMING FOR OPTIMUM RESERVOIR OPERATION1

ABSTRACT. For a multipurpose single reservoir a deterministic optimal operating policy can be readily devised by the dynamic programming method. However, this method can only be applied to sets of deterministic stream flows as might be used repetitively in a Monte Carlo study or possibly in a historical study. This paper reports a study in which an optimal operating policy for a multipurpose reservoir was determined, where the optimal operating policy is stated in terms of the state of the reservoir indicated by the storage volume and the river flow in the preceding month and uses a stochastic dynamic programming approach. Such a policy could be implemented in real time operation on a monthly basis or it could be used in a design study. As contrasted with deterministic dynamic programming, this method avoids the artificiality of using a single set of stream flows. The data for this study are the conditional probabilities of the stream flow in successive months, the physical features of the reservoir in question, and the return functions and constraints under which the system operates.     

LAND USE CHANGE PATTERNS BY LOCATION WITH RESPECT TO A RESERVOIR1

Much research has been done to determine the benefit of a water resources development to society as a whole. Some research has explored the benefit of such a facility to a region. Very little research exists on the effects of a reservoir on the immediately surrounding area. The general hypothesis of this study is that the spatial patterns of land use change are influenced by economic characteristics of the reservoir and reservoir area. Several hypotheses concerning the effects of relative location on a peninsula are tested using analysis of variance. The data used for the analysis is based on Lake Cumberland, a reservoir in southern Kentucky. The analysis indicates that there exists significant patterns of land use change around the lake and on peninsulas.     

APPLICATION OF THE GENETIC ALGORITHM FOR OPTIMIZING OPERATION RULES OF THE LiYuTan RESERVOIR IN TAIWAN1

ABSTRACT: A procedure to apply genetic algorithm to optimize operation rules is proposed and applied to the LiYuTan Reservoir in Taiwan. The designed operation rules are operation zones with discount rates of water supply. The first step of the procedure is to predefine the shape of boundary curves of operation zones according to reservoir storage routing. Then, relatively fewer variables are used to describe the curves, and a last genetic algorithm (GA) is applied to optimize the curves. The procedure is applied to the newly built LiYuTan Reservoir for increasing domestic water demands. Shortage index is used to evaluate the performance of operation zones. A year is divided into 36 operational periods, with each month containing three operational periods. The shortage indexes calculated in operational periods are 9.81, 8.27, and 7.13, respectively, for the reservoir without operation rules, applying operation zones optimized by GA with encoding 36 storage levels for each curve, and adopting operation zones optimized by GA with encoding the curves with predefined shape. The average deficits for the three cases are 77.2, 43.6, and 33.3 (10⁴ m³/day), respectively. The results indicate that operation zones optimized by the proposed procedure have smaller shortage indexes and lower average deficits. In addition, the optimized operation zones have less variation and thus are more practical for operation. Conclusively, the proposed procedure utilizing GA to optimize operation zones with predefined shape can provide better and realistic outcomes through limited iterations.     

UNCERTAINTY BASED OPERATION OF LARGE SCALE RESERVOIR SYSTEMS: DEZ AND KAROON EXPERIENCE1

ABSTRACT: Reservoir operation involves a complex set of human decisions depending upon hydrologic conditions in the supply network including watersheds, lakes, transfer tunnels, and rivers. Water releases from reservoirs are adjusted in an attempt to provide a balanced response to different demands. When a system involves more than one reservoir, computational burdens have been a major obstacle in incorporating uncertainties and variations in supply and demand. A new generation of stochastic dynamic programming was developed in the 1980s and 1990s to incorporate the forecast and demand uncertainties. The Bayesian Stochastic Dynamic Programming (BSDP) model and its extension, Demand Driven Stochastic Dynamic Programming (DDSP) model, are among those models. Recently, a Fuzzy Stochastic Dynamic Programming model (FSDP) also was developed for a single reservoir to model the errors associated with discretizing the variables using fuzzy set theory. In this study the DDSP and the FSDP models were extended and simplified for a complex system of Dez and Karoon reservoirs in the southwestern part of Iran. The simplified models are called Condensed Demand Driven Stochastic Programming (CDDSP) and Condensed Fuzzy Stochastic Dynamic Programming (CFSDP). The optimal operating policies developed by the CDDSP and the CFSDP models were simulated in a classical model and a fuzzy simulation model, respectively. The case study was used to demonstrate the advantages of implementing the proposed algorithm, and the results show the significant value of the proposed fuzzy based algorithm.     

The International Environmental Expert Panel for Major Dam/Reservoir Projects: The Yellow River, China

The experience of the International Expert Panel on Environment for the Xiaolangdi dam/reservoir project in China (XEP) showed that the Panel meetings resulted in a marked improvement in project environmental performance by all parties participating in project implementation, with no parties exempt from the Panel's evaluations. Unfortunately the Loan Agreement authorizes use of the Panel only through the project stages of final design and construction, hence the 12th Panel meeting, which matched project construction completion, ended this series. The Panel has recommended that some meetings of the Panel be held during the project's operations stage in order to maintain continuing attention to environmental needs. The XEP experience showed that the XEP, in addition to monitoring project environmental performance, was very valuable for (i) training of Chinese staff involved in project implementation, and (ii) serving in the role as expert consultant for guiding the work of the Chinese participants. The XEP experience also showed the need for making a clear separation between evaluation, the overall resettlement program per se, and the environmental effects of the program. The Panel recommended that the Ministry of Water Resources and World Bank cooperate in sponsoring a book on The Environmental History of the Xiaolangdi Project, including both dam construction as well as resettlement problems, which would serve as a very valuable reference for guiding environmental planning for future dam projects in China (Ludwig, H.F. 1994–2000).     

三峡库区滑坡稳定性评价研究

三峡水库蓄水后 ,库水位将在 14 5～ 175m范围内波动 ,动水压力和水的软化作用是滑坡失稳的主要因素。库区滑坡稳定性评价规范要求采用不平衡推力法 ,但在考虑库水位下降产生的渗透力时 ,对渗流浸润线的确定缺乏理论依据 ,更没有实测数据的支持。为此 ,笔者运用一维的布辛内斯克方程 ,研究三峡水库蓄水后库水位下降和暴雨作用下滑坡渗流浸润线的变化规律 ;建立了渗流作用下滑坡稳定性评价模型 ;分析降速、渗透系数、暴雨等对滑坡稳定性的影响。     

RESERVOIR RELEASES TO USES WITH DIFFERENT RELIABILITY REQUIREMENTS1

ABSTRACT: Releases from a reservoir may be allocated to a number of uses, each of which may require a given volume of water at a different reliability. The paper provides a method that can be used to estimate the volume of water associated with a given reliability for each use of water when the proportion of releases allocated to each use is known. These results can be used to evaluate the meeting of specified objectives under a published release policy derived by stationary stochastic dynamic programming. The results can also be used to solve water allocation problems when the probability distribution of available water is known (or can be estimated) and water has multiple uses, each of which has different volume and reliability requirements.