摘要:

It is possible to develop operating rules for the conjunctive use of surface water and groundwater when the demand and supply sources are stochastic. These rules allow the quantities of water pumped from wells, diverted from streams, spread, and returned to the stream after use to be determined for a given time period even if the required needs and availability of supply are uncertain at the beginning of the time period. These rules are dependent on a technological function relating streamflow interaction with well pumping and with the statistics of the demands, streamflow, pumping, and drawdowns.

ISSN:0043-1397    

DOI:10.1029/WR010i001p00001

年代:1974

数据来源: WILEY

摘要:

This paper considers the regulation of the water levels of Lake Superior, which can be controlled at its outlet. The inflows to the lake were treated as stochastic random variables, and the objective was to find operating policies that minimized the expected undiscounted yearly losses over an infinite time horizon. The system was modeled as a periodic Markovian decision problem. A new algorithm based on White's method of successive approximations for solving single chained and completely ergodic Markovian decision problems was developed and was proven to be fairly efficient in terms of computer storage and computation time. Transition probabilities of the inflows were estimated from 64 years of data. The economic loss functions used in the model considered the losses due to navigation inconvenience and shore property damage. An extensive sensitivity analysis was conducted to determine their influence on the optimal operating policies. To show the validity of the model, the newly developed policies were tested against the current operating policy by using the historical inflow record as data. The results show that if some of the developed operating policies were adopted, the average yearly losses could be reduced by at least 15%. At the same time the monthly lake level variances could be reduced by 25%.

ISSN:0043-1397    

DOI:10.1029/WR010i001p00011

年代:1974

数据来源: WILEY

摘要:

A methodology is developed for optimal design and/or operation of a water distribution system that is to operate under one or several loading conditions. Decision variables may be design variables, such as pipe diameters, or control variables, such as heads and flows. The objective function may include the initial cost of the design, the cost of operation, the physical measures of performance, and the penalties for violating constraints. Constraints may be imposed on the decision variables and on the performance of the system under each loading. Flow solutions are obtained by a modified Newton‐Raphson method employing sparse matrix techniques. Optimization is obtained by a combination of the generalized reduced gradient and penalty methods. Implementation in a computer program and its use on a test problem in both batch and time‐sharing modes are described, and it is concluded that the method is computationally feasible. The many different ways in which it can be used to analyze, design, and operate water distribution systems are outli

ISSN:0043-1397    

DOI:10.1029/WR010i001p00027

年代:1974

数据来源: WILEY

摘要:

Dams and reservoirs are often partially justified on the basis of an intangible benefit related to the property value changes that they allegedly induce. This assumption is tested by using the G. Ross Lord Dam and parkland on the west Don River in Toronto. The project had virtually no impact on residential property values in the summer of 1972 while the dam was under construction. The magnitude of the social benefit related to the residential land value changes induced by such a project is considered.

ISSN:0043-1397    

DOI:10.1029/WR010i001p00037

年代:1974

数据来源: WILEY

摘要:

Multiple‐objective optimization problems naturally arise in resource management projects. A chief difficulty with multiple‐objective optimization is that it is no longer clear what one means by an optimal solution. A possible remedy to this situation is to refine the concept of ‘optimal solution’ by introducing the so‐called ‘noninferior solution set.’ Then optimization, in a multiple‐objective context, boils down to determining the set of noninferior solutions. Determination of the noninferior set is facilitated by relating it, in a one‐to‐one manner, to a family of auxiliary scalar optimization problems. For a certain class of problems the entire noninferior set can be obtained by solving the auxiliary scalar problem. This procedure is illustrated by means of a problem that commonly occurs in water resource plan

ISSN:0043-1397    

DOI:10.1029/WR010i001p00044

年代:1974

数据来源: WILEY

摘要:

The dimensionality of certain sequencing and scheduling problems can be reduced by exploiting their special structures. An example of this type of reduction of dimensionality is presented in the form of a theorem. The use of the theorem in the dynamic programing solution of a previous example is discussed. Sufficient conditions for the optimality of a myopic decision rule are also shown to be a special case of the theorem.

ISSN:0043-1397    

DOI:10.1029/WR010i001p00049

年代:1974

数据来源: WILEY

摘要:

Stochastic dynamic programing can be used to derive optimum operating policies that maximize the expected net dollar benefits for a water resource system. It is shown that these policies may give rise to significant probabilities of system failure. Such probabilities can be estimated by system simulation. A procedure is proposed in which the combined use of dynamic programing and simulation allows an optimum operating policy to be derived that will maximize the expected net benefit and yet not violate constraints on the probability of failure. Limitations to failure are applied directly by imposing a fixed penalty on the system whenever it fails, thus inducing amendments in the optimum policies derived. Further developments of the technique are foreshadowed.

ISSN:0043-1397    

DOI:10.1029/WR010i001p00051

年代:1974

数据来源: WILEY

摘要:

This paper outlines a method whereby the timing, sequencing, and sizing of a water supply development is validly performed. The method takes care of the vital fact that although it is firm water that is demanded or sold, it is reservoir capacity at a particular site that is costed, and the two are not simply related, nor is the relationship independent of previously constructed reservoirs and the stream‐reservoir configuration. A feature of this method is a simple firm water determination concept that is applicable to any steam‐reservoir configuration and that uses rational and reasonable operating rules at each basic time period for the calculations of reservoir storage changes resulting from excess or deficit streamflows relative to demand in those periods. Details of interchanges of water between reservoirs are not relevant to this concept. Streamflows are taken to be the subnormal flow hydrographs that would correspond to a critical period analysis method, but no advantage is taken of any supposed knowledge about future fl

ISSN:0043-1397    

DOI:10.1029/WR010i001p00057

年代:1974

数据来源: WILEY

摘要:

This paper investigates the effect of input model, size of reservoir, and various input parameters on the probability of zero draft from a discrete reservoir fed by a serially correlated input. It appears that the form of the transition probability matrix describing the input (assumed to be a finite Markov chain) has relatively little effect on the probability of zero draft.

ISSN:0043-1397    

DOI:10.1029/WR010i001p00063

年代:1974

数据来源: WILEY

摘要:

The characteristics and economic implications of thermal pollution are considered within the context of the planning of a treatment system for a series of hypothetical nuclear power plants that are to be located adjacent to a river. It is assumed that these power plants will discharge sufficient heated cooling water to make these treatment facilities necessary. The problem that is being considered is to determine the optimal planning of a treatment system. The objective of the planning procedure is to minimize the total annual cost for the construction and operation of the entire system. The constraint on this minimization process is not to violate a maximum temperature requirement within each reach or section of the river. The problem is solved by considering the effect that a bypass‐piping system has on temperatures within the river. The technique of bypass piping consists of piping waste water downstream to reaches of a river where the regenerative powers of the physical system have reduced the level of pollution to the extent that more waste water may be disposed. By noting that the bypass‐piping system allows the beginning and end temperatures of a section of the river to be controlled, a procedure can be developed for separating the optimization model of the entire system. This model is separated into a set of small subproblems that are solved by simulation and a system problem that is solved by dynamic programing. The results of the implementation of this model showed that the bypass‐piping system significantly reduced the cost of the entire treatment s

ISSN:0043-1397    

DOI:10.1029/WR010i001p00067

年代:1974

数据来源: WILEY