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2002 | Buch

Hydrological Dimensioning and Operation of Reservoirs

Practical Design Concepts and Principles

verfasst von: Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa

Verlag: Springer Netherlands

Buchreihe : Water Science and Technology Library

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Über dieses Buch

Storage reservoirs represent one of the most effective tools for eliminating, or at least for minimizing, discrepancies in the time and space variations of water resources distribution and requirements. In fact, the different - often contradictory - and increasing demands on water resources utilization and control usually can be fulfilled only by building multi-purpose reservoir systems. In this way, the available water resources can be exploited and/or managed in a more rational way. Typically, the construction of a dam across a river valley causes water to accumulate in a reservoir behind the dam; the volume of water accumulated in the reservoir will depend, in part, on the dimensions of the dam. The size of the dam will normally affect the capital expenditure in a very significant way. Indeed the construction of large water resource control systems - such as dams - generally involves rather huge manpower and material outlays. Consequently, the elaboration of effectual methods of approach that can be used in establishing the optimal reservoir parameters is of great practical significance. For instance, in the design and operation oflarge multi-reservoir systems, simple simulation and/or optimization models that can identify potentially cost­ effective and efficient system design are highly desirable. But it should be recognized that the problem of finding optimal capacities for multi-reservoir systems often becomes computationally complex because of the large number of feasible configurations that usually need to be analyzed.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
Why the need for reservoirs in water resources management programs? Simply, for the regulation and control of natural water flow patterns and regimes — in order to meet and satisfy the spatial and temporal water needs of society. In fact, prospects for improved standards of living in many regions of the world hinges in part on the development and rational management of water resources systems — including the construction of dams and/or reservoirs. Flow regulation in water resources management is indeed one of the most important tools for supporting irrigation to boost food production; for the protection of life and property by mitigating the destructive effects of floods and droughts; and for the generation of energy to supply electricity — among other things. Some of these benefits cannot be realized without the construction of dams and, subsequently, the effective operation of the concomitant storage reservoirs.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 2. The Hydrology of Flow Regulation
Abstract
Flow regulation is a consciously performed re-distribution of runoff — often achieved by use of human-controlled hydraulic control structures such as storage reservoirs (see illustration in Figure 2.1). There are two basic types of flow regulation schemes — depending on whether the purpose of the control structure is to stabilize some lower limit of outflow (i.e., low-flow regulation) or some upper limit to maintain a certain degree of flood protection (i.e., flood control). In flow regulation schemes using storage reservoirs, that portion of the reservoir volume that can be used for the flow regulation is referred to as the reservoir storage capacity.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 3. Planning for Dams and Reservoirs: Hydrologic Design Elements and Operational Characteristics of Storage Reservoirs
Abstract
In any region where a new storage reservoir is being proposed, the area must be carefully surveyed to establish suitable sites for the construction of the dam. Each alternative site will then receive a detailed assessment to determine the size of dam that can be constructed and the corresponding storage-area-elevation relationships. With a choice of dam sites and various reservoir sizes, the hydrologist or analyst must now assess the water yield from each site and the magnitude and frequency of extreme floods and low flows. This information will facilitate the selection of the best site to satisfy the water demands of the region, as well as provide flow criteria for the design of the outflow structures and the assessment of compensation water releases required for low flow conditions. In addition, where other reservoirs already exist within the river system/network, an assessment is required of the effect of the new reservoir on inflows and outflows of these existing reservoirs. Invariably, the science of hydrology plays crucial roles throughout these exercises.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 4. Principles and Concepts in the Hydrologic Design and Operation of Storage Reservoirs
Abstract
This chapter discusses key fundamental principles and concepts that will help in the efficient design of water control systems — and also make it possible to develop and implement optimal reservoir design and operation management decisions. In fact, of significant, even fundamental importance in the hydrologic design and operation of water management systems are the concepts of risk and reliability. In general, regardless of the type of reservoir storage provided or its mode of operation, an element of hydrologic risk exists in all such systems due to the inherent possibility for system failures to occur. Thus, complete disregard of failure probability in the systems analysis may introduce negative elements similar to the statistical problem of the so-called ‘ruin of the gambler’ into the project. Indeed, it is important to include risk elements into the hydrologic design of reservoirs in order to assure the birth of a reliable system.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 5. Systems Approach in the Hydrologic Design and Operation of Storage Reservoirs
Abstract
Systems analysis in water resources offers a philosophical approach to studying the interdependence within the hydrologic, environmental, and economic elements under one umbrella — with an ultimate goal of improving system performance. The systems approach is generally defined as an orderly way of looking at all angles of a complex problem, with emphasis on the interrelationship rather than the analysis of separate parts of a given phenomenon (Albertson et al. 1971).
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 6. Hydrologic Analysis of Flood Flows
Abstract
Floods and its devastating effects have been known from the beginning of life on earth. Its prevention or mitigation is therefore of high importance — to ensure a sustained human and ecological life. The purpose of flood control is to eliminate or reduce damage caused by the flooding of areas adjacent to rivers, or by the overtopping of engineering structures like dams, embankments or bridges. Flood control may be accomplished by means of the following general types of hydraulic structures:
1.
Reservoirs — where part of the flood waters can be temporarily retained to help reduce the flood peak, and the passage of water masses is stretched over a longer period of time at a reduced flow rate; or
 
2.
Levees — built along rivers to protect the adjoining areas by confining the flood to a particular channel, and in which case the flood peak may be increased because of the elimination of storage in areas that otherwise would have been inundated.
 
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 7. Methods of Approach for Designing Optimal Storage Capacities and Operational Strategies for Multireservoir Systems
Abstract
In the analysis of a reservoir development scheme, a number of alternative dam sites would typically be investigated, not only for the construction requirements but also from the hydrologic point of view. Procedures used for rapid assessment — usually designated as preliminary design techniques — involve making simplifying assumptions for ease of application; as a consequence, such procedures often result in a reduced accuracy. After using preliminary design techniques to eliminate unsuitable reservoir sites from further consideration, the remaining locations are evaluated by using a final design technique; these latter techniques tend to be more complicated and/or sophisticated because they take into account most, if not all, of the factors which influence storage (McMahon and Mein, 1986, 1978).
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 8. Determination of the Optimal Reservoir Storage Capacity and Operational Parameters for a River Dam
Abstract
Reservoir systems for flow regulation generally involve highly dynamic decisions. Of particular interest, the optimal system design may be defined as that combination of system units/components, inputs, outputs, and operating policies that ‘extremizes’ (i.e., maximizes or minimizes, as appropriate) the objective function — thus fulfilling the overall objective better than any other combination. The problem of finding the optimal capacities for the components in multireservoir systems, especially in situations where reservoirs are acting both in parallel and in series, becomes computationally complex due to the rather large number of feasible configurations that need to be analyzed. Typically, mathematical programming — involving mathematical optimization techniques — guarantees an optimal solution to this type of problem. However, because the problem formulation only approximates the real problem, the optimal solution obtained by mathematical optimization techniques usually is only an approximation of the optimal strategy for the system. Nonetheless, a good solution — including an analysis of the sensitivity of the solution to changing conditions — may be derived less expensively in this manner.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 9. Hydrological Sizing of Reservoirs for Flood Protection
Abstract
A flood wave passing through a reservoir is both delayed and attenuated as it enters and spreads over the pool surface; the process depends on the regime and type of the reservoir. The overall objective in a typical flood protection program is the retention of the water volume of the flood waves, partially or fully in the reservoir — thus enhancing the safety of the downstream areas. From a hydrologic point of view, this means the conversion of the time-function of the upstream discharges into the time-function of the downstream flows. The conversion depends on the geometric and hydraulic features of the pool, as well as on the reservoir operation. Good knowledge of this modifying effect is important to determining the proper design parameters and the reservoir operation schedule.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Chapter 10. Application of the Moran Model in Reservoir Storage Design
Abstract
The application of the Moran theory (that is based on transition probabilities) to solve water storage-related problems seem to have found only limited applications in the past. A transition probability matrix shows the probability that a variable will assume any given value at the end of a time period, given that it has any specific value at the beginning of the period (McMahon and Mein, 1986). The reservoir states can be expressed in a transition matrix that shows the probability of finishing in a particular state as a function of the starting state. In view of the great potential utility of the transition probability matrix approach in the hydrological dimensioning of reservoirs, this chapter offers a discussion of some new efforts made in this direction — and we trust that water resources specialists will find these topics relating to the application of transition probabilities in the reservoir design effort to be of great interest.
Imre V. Nagy, Kofi Asante-Duah, Istvan Zsuffa
Backmatter
Metadaten
Titel
Hydrological Dimensioning and Operation of Reservoirs
verfasst von
Imre V. Nagy
Kofi Asante-Duah
Istvan Zsuffa
Copyright-Jahr
2002
Verlag
Springer Netherlands
Electronic ISBN
978-94-015-9894-1
Print ISBN
978-90-481-5942-0
DOI
https://doi.org/10.1007/978-94-015-9894-1