共查询到20条相似文献,搜索用时 15 毫秒
1.
Patrick C. Mann John L. Mikesell 《Journal of the American Water Resources Association》1976,12(5):995-1004
ABSTRACT: Two types of organizational systems provide most of the water service in the United States. The investor-owned firm operates on a profit basis generally subject to state commission regulation. The government-owned firm is generally confronted by local control. The comparative efficiency of private versus government firm provision of water services is essentially an empirical issue. Unit costs and other operating statistics are examined for water firms of each ownership form. The analysis shows that private firms tend to have higher operation costs than do government firms, possibly attributable to wage-salary differentials. The analysis also indicates that capital investment in large government firms may result in diseconomies. The analysis creates serious doubt as to whether efficient provision of water services can be better facilitated by large mergers of either ownership form. 相似文献
2.
Patrick C. Mann John L. Mikesell 《Journal of the American Water Resources Association》1979,15(5):1301-1307
ABSTRACT: Several factors theoretically affect the cost behavior of water systems. These factors include scale, consumer density, and per capita usage. This analysis examines the several possible influences on the unit costs of water service. The statistical analyses indicate that among the factors of scale, per capita use, and consumer density, only the first two factors are important influences on water system costs. Water consumers appear to benefit from being served by large systems and being located in service areas characterized by relatively high per capita consumption. There is little statistical evidence indicating that more dense areas can be provided water service at lower costs than less dense areas. 相似文献
3.
4.
Richard A. Andrews 《Journal of the American Water Resources Association》1971,7(5):905-912
ABSTRACT. This study investigates economies associated with size of New England water utilities. Regression analysis techniques were applied to annual water cost and production data reported in the American Directory of Water Utilities (1968-1969). Modest economies of size in the production of water were found. Because in large communities more water is used per person, total cost increases at a slightly faster rate than population increases, but per unit costs of producing water decline. Substantial economies occurred when the number of customers was held constant and volume of water per customer increased. This study indicates possible economies when two or more of the many very small utilities combine activities to form a larger unit and by encouraging present customers to use more water. 相似文献
5.
Charles Brendecke Leonard Ortolano 《Journal of the American Water Resources Association》1981,17(2):248-254
ABSTRACT: Survey data from samples of two types of Corps of Engineers planning studies have been collected. The nature of significant environmental issues affecting the studies was ascertained. Information concerning District administrative practices and communication patterns and extraorganizational coordination procedures was also obtained. Statistical analysis examined the relationships between these practices and procedures and the consideration given environmental issues in plan formulation and modification decisions. Environmental issues receive greater consideration in plan formulation decisions where District policies encourage interdisciplinary planning and direct communication between planners and environmental interests. Plan modification decisions reflect environmental considerations to a greater degree where significant controversy exists and where reviewing agencies actively pursue environmental issues. 相似文献
6.
H. J. Vaux 《Journal of the American Water Resources Association》1977,13(3):469-478
ABSTRACT: Liquid dominated geothermal systems are expected to account for most of the growth in geothermal energy production in the coming decades. Production of water from such systems could significantly augment fresh water supplies. The feasibility of water exploitation is clouded by potential problems related to seismic impacts, land subsidence and the composition of geothermal brines. If these problems can be overcome at little cost, desalination of brines may be feasible. Estimates of water production costs are presented for a variety of desalination technologies, plant sizes and brine water compositions. These estimates show that production costs will range from $139.10/A.F. to $436.00/A.F. at the plant boundary. Economies of scale and brine composition are important determinants of cost. Production costs are substantially in excess of the value of water in alternative uses. However, in certain unique situations, it may be efficient to desalt brines for use in upgrading the quality of municipal water, industrial process water and irrigation water. Unique situations aside, geothermal brines are not likely to provide an economical source of fresh water in the absence of striking changes in the patterns of supply and demand for water. 相似文献
7.
Ganapathi Ramamurthy David L. Chicoine 《Journal of the American Water Resources Association》1984,20(2):255-260
ABSTRACT: In the last two decades the federal government has provided substantial capital to construct rural water distribution systems. Loans at subsidized interest rates and front-end grants through the Farmers Home Administration have been the main source of this capital. Recent federal policy redirections have reduced substantially the availability of grants and subsidized loans. Because of design and material differences, capital cost estimates from urban systems are not uniformly applicable to rural water services. This study presents an econometric analysis of capital costs, using Illinois rural water system construction contract bids. Cost equations by systems components representing 90 percent of capital costs are estimated. The type of information developed here can be used in initial planning and optimization design models contributing to the efficient provision of rural water services. 相似文献
8.
Warren Viessman 《Journal of the American Water Resources Association》1985,21(2):311-314
Understanding social goals and objectives and incorporating them in water resources planning, management, education and engineering processes is the key to solving many current and emerging water resources problems. Water resources professionals must turn more of their attention to this issue. Various avenues are open for their involvement. They include lobbying, participating in government, education and research, publishing, establishing institutions, interacting with the public and analyzing existing systems. 相似文献
9.
ABSTRACT: Because of its importance and the perceived inability of private sector sources to meet water demands, many countries have depended on the public sector to provide water services for their populations. Yet this has resulted in many inefficient public water projects and in inadequate supplies of good quality and reliable water. Decentralization of water management, including the use of water markets, cannot solve all of these water problems, but it can improve the efficiency of water allocation. When given adequate responsibility and authority, water user associations have effectively taken over water management activities at a savings to tax payers. Moreover, water markets add the potential benefit of improving water efficiency within a sector as well as providing a mechanism for reallocating water among sectors. The key question involves developing innovative mechanisms for reducing the transaction costs of organizing water users and of making water trades. Water rights need to be established which are recorded, tradable, enforceable, and separate from land if markets are to operate effectively. Also, institutions are needed that effectively resolve conflicts over water rights, including third party impacts and water quality concerns. 相似文献
10.
Martha W. Gilliland Gerald P. Wallin Ronald Smaus 《Journal of the American Water Resources Association》1989,25(1):49-61
ABSTRACT: Nebraska has abundant supplies of high quality surface and ground water. The U.S. Supreme Court decision in 1982, declaring ground water to be an article of commerce, is widely perceived as giving neighboring states easier access to Nebraska water. Some neighboring states, particularly Colorado and Wyoming, are in water short situations. Additionally, current legal restrictions on certain types of transfers within the State could be inhibiting the “highest and best use” of Nebraska's water. Thus, in 1987 the Nebraska Legislature called for the development of a new water policy for Nebraska that would promote the economically efficient use of water, yet protect the environment as well as the rights of individuals (for example, third parties) and the public. Through an interagency study employing an extensive public involvement process, a policy to be recommended to the Legislature in 1989 emerged. The policy revises the basic definition of water rights and transfers and eliminates most of the inconsistencies in the water allocation system by treating most types of water resources, most types of water users, and most locations of use similarly in the permitting process. (The principal exception is the individual irrigator using ground water on the overlying land where overlying land is one government surveyed section; such use is not defined to be a transfer nor is a permit required.) An impact assessment would be required of most new water uses except on site uses of ground water. Compensation measures could be specified as a condition of the permit where appropriate. The permit would be issued only if the benefits of the proposed transfer clearly outweigh adverse effects that could not be avoided or effectively compensated. The policy allows for the sale or lease of “salvaged” water. It calls for the State to facilitate transfers by acting as a clearinghouse for potential buyers and sellers, and it allows the State to sponsor water projects. An annual fee to be paid by many water users, in order to provide a fund for compensation and for state sponsored water projects, was proposed. However, it met with extensive opposition. Thus, the policy recommends only that the Legislature examine potential funding programs and equitable user fees. 相似文献
11.
Asit K. Biswas 《Journal of the American Water Resources Association》1973,9(4):746-754
Historically, the main objective of water resources development has been economic efficiency, and the technique for its evaluation has been benefit-cost analysis. Gradually other objectives have emerged, and these in order of their emergence are regional income redistribution, environmental quality and social well-being. These multi-objectives have given rise to multifarious problems, and have made the planning process much more complex than ever before. The different objectives are not mutually exclusive, and, hence, contributions to one can only be made at the expense of others. Trade-off studies between different objectives are difficult to make. It is suggested that one way to overcome this difficulty could be to design a system to perform optimally in terms of one objective, subject to a specified level of performance of the other, which in effect becomes a constraint. The paper also discusses the pros and cons of the desirability of public participation in our decision-making processes, and the necessity of developing social sciences models to aid water planning and management. 相似文献
12.
S. Lawrence. Dingman Stephen C. Lawlor 《Journal of the American Water Resources Association》1995,31(2):243-256
ABSTRACT: This study systematically develops, validates, and compares alternative approaches for estimating quantiles of the distribution of annual minimum seven-day-average flows (7Q) for ungaged, unregulated drainage basins in New Hampshire and Vermont via regression on map-measurable drainage-basin characteristics. At 47 gaging stations in the region, the hypotheses that 7Q is log normally distributed and serially independent are not rejected, and the regional average spatial correlation is R= 0.35. Step-forward examination of a suite of potential predictor variables revealed that logarithm of drainage area, mean elevation, and fraction of basin covered with sand and gravel deposits are significant predictors of quantiles of 7Q. The regression equations were incorporated into four approaches to estimate the 7Q value with a nonexceedence probability of 0.1, 7Q10. Comparison of observed values and values predicted via a delete-one jackknife resampling validation indicates that one of the approaches gives estimates with acceptable bias and precision, with median relative error of 33 percent and prediction error of 64 percent. This is equivalent to the precision obtainable with only one to two years of gaging records. In spite of this limited precision, the approaches developed herein are useful for predicting 7Q quantiles at ungaged sites. Further improvement in precision will likely be possible only by exploiting the spatial correlation of annual 7Q. 相似文献
13.
S. Lawrence Dingman 《Journal of the American Water Resources Association》1981,17(4):684-690
: In general, the choice among reservoirs for water supply or flow augmentation is a multiobjective problem. Choices are based in part on the yield available from water supply reservoirs or, in the case of flow augmentation reservoirs, on the increase in low flows at downstream locations. Detailed estimates of these effects may be too costly for basin planning purposes. Thus this paper presents methods for rapid estimation of those quantities for New Hampshire. For water supply reservoirs, a composite empirical relation between Y95 (the draft available 95 percent of the time) and storage ratio, S*, is developed from previous studies in the region. For flow augmentation reservoirs, empirical relations between S* and degree of regulation, R*, are applied to each upstream regulating reservoir. Values of regulation arc then summed and divided by the mean flow at the downstream reach of interest. This parameter, (ΓR)*, is then related to increase in flow available 95 percent of the time by an empirical relation. 相似文献
14.
Eric L. Hyman David H. Moreau Bruce Stiftel 《Journal of the American Water Resources Association》1984,20(6):915-922
SAGE, a proposed method for environmental assessment, focuses on eliciting and incorporating value weights in multiple-objective decision making. In this method, the value weights are inferred from the tradeoffs that people make in choices about alternatives. These weights are applied to scaled scores for accounts based on measurable attributes of each objective. In order to indicate the political ramifications of decisions and to facilitate sensitivity analysis, the values held by various groups are presented in matrix from arrayed by group affiliation or by judgment types that share common values. Results of a trial application of SAGE to a land use/watershed management problem in a growing urban area are presented. 相似文献
15.
Jim C. Loftis Graham B. McBride Julian C. Ellis 《Journal of the American Water Resources Association》1991,27(2):255-264
ABSTRACT: An assumption of scale is inherent in any environmental monitoring exercise. The temporal or spatial scale of interest defines the statistical model which would be most appropriate for a given system and thus affects both sampling design and data analysis. Two monitoring objectives which are strongly tied to scale are the estimation of average conditions and the evaluation of trends. For both of these objectives, the time or spatial scale of interest strongly influences whether a given set of observations should be regarded as independent or serially correlated and affects the importance of serial correlation in choosing statistical methods. In particular serial correlation has a much different effect on the estimation of long-term means than it does on the estimation of specific-period means. For estimating trends, a distinction between serial correlation and trend is scale dependent. An explicit consideration of scale in monitoring system design and data analysis is, therefore, most important for producing meaningful statistical information. 相似文献
16.
Jiansheng Yan Keith R. Smith 《Journal of the American Water Resources Association》1994,30(5):879-890
ABSTRACT: The unique characteristics of the hydrogeologic system of south Florida (flat topography, sandy soils, high water table, and highly developed canal system) cause significant interactions between ground water and surface water systems. Interaction processes involve infiltration, evapotranspiration (ET), runoff, and exchange of flow (seepage) between streams and aquifers. These interaction processes cannot be accurately simulated by either a surface water model or a ground water model alone because surface water models generally oversimplify ground water movement and ground water models generally oversimplify surface water movement. Estimates of the many components of flow between surface water and ground water (such as recharge and ET) made by the two types of models are often inconsistent. The inconsistencies are the result of differences in the calibration components and the model structures, and can affect the confidence level of the model application. In order to improve model results, a framework for developing a model which integrates a surface water model and a ground water model is presented. Dade County, Florida, is used as an example in developing the concepts of the integrated model. The conceptual model is based on the need to evaluate water supply management options involving the conjunctive use of surface water and groundwater, as well as the evaluation of the impacts of proposed wellfields. The mathematical structure of the integrated model is based on the South Florida Water Management Model (SFWMM) (MacVicar et al., 1984) and A Modular Three-Dimensional Finite-Difference Groundwater Flow Model (MODFLOW) (McDonald and Harbaugh, 1988). 相似文献
17.
Gilbert F. Cochran 《Journal of the American Water Resources Association》1971,7(4):689-699
ABSTRACT The Las Vegas Valley in southern Nevada has provided ample opportunity for mission oriented water resources research, and, to some extent, application of those research results. Past studies of the ground-water systems have resulted in the construction of a direct electrical analog, two digital simulation models, a Hele-Shaw fluid analog, a linear programming model, and two dynamic programming models. The work accomplished has dealt with the problems of groundwater management, waste water reclamation and artificial recharge, and conjunctive use water management. The current study is attempting to integrate previous results and new work into a detailed and realistic conjunctive use water resource management model to achieve system efficiency under more than one criteria. The research team is interdisciplinary in nature and encompasses the physical and social sciences. 相似文献
18.
William Whipple Donald Duflois Neil Grigg Edwin Herricks Howard Holme Jonathan Jones Conrad Keyes Mike Ports Jerry Rogers Eric Strecker Scott Tucker Ben Urbonas Bud Viessman Don Vonnahme 《Journal of the American Water Resources Association》1999,35(4):713-716
ABSTRACT: The planning and developing of water resources to meet the country's needs for water supply, flood control, hydroelectric power, irrigation, and navigation now needs to take more account of environmental needs and regulations. Water resource development is often beneficial to the environment, but may also be harmful, as in cases involving salmon and various other endangered species. As a national objective, the environment must be preserved and in some cases restored; but how can this be done consistent with other national objectives, relating to life and welfare of human beings? This problem has aroused the concern of many engineers and water scientists. As a result, a national conference on this subject was held in Chicago in June 1998, as an integral part of ASCE's Annual Conference on Water Resources Planning and Management and the Annual Conference on Environmental Engineering. At the conclusion of that conference, a post-conference meeting was held by a group of prominent water resource practitioners. It was concluded at this meeting that action should be taken by our government to establish a new form of interagency approach, involving the states, as a means of coordination in cases of national importance. 相似文献
19.
Marshall Gysi 《Journal of the American Water Resources Association》1980,16(4):676-680
ABSTRACT: Most of us are aware, or feel we are aware, of the impacts of major water resources projects on our lives. “Dam-lovers” note the life-saving flood-risk reduction and recreational benefits of a proposed reservoir, while “dam-haters” bemoan the future drowning out of the wildlife habitat of its river valley, and the recreational disbenefits to stream (as opposed to lake) fishermen. Water supply projects can often be given such a revered status, assuming the “obvious” tenet that water, air, food, and shelter are basic requirements of decent living, that the economic viability of the project may not even be assessed. Water resources planners are supposed to impartially weigh the environmental and economic benefits, and especially now, the energy implications of all proposed water projects, but many times the partial views of political or public advocates may be hard to ignore. The assumptions used in the planning of four recent water projects in the Province of Alberta will be presented and some revisions suggested which materially affect their Benefit/Cost ratios. In one project that is still in the public hearing stage, the economic analysis will be revealed, indicating that the original B/C ratio of about 1.6:1 might be more realistically placed at 0.6:1. In another project just completed, the apparent lack of an economic or energy analysis that has resulted in a perpetual and unnecessary energy load on the province, will be described. 相似文献
20.
T.C. Winter J.S. Eaton G.E. Likens 《Journal of the American Water Resources Association》1989,25(5):991-1008
ABSTRACT: Measured stream discharge plus calculated ground water discharge (total measured runoff) were compared with runoff calculated by the unit-runoff method for the two largest watersheds of Mirror Lake for 1981–1983. Runoff calculated by the unit-runoff method, using Hubbard Brook watershed 3 as the index watershed, was greater than the total measured runoff into Mirror Lake during periods of high flow and slightly less than the total measured runoff into Mirror Lake during periods of low flow. Annual calculated unit runoff was 17 to 37 percent greater than total measured runoff. Differences in monthly runoff are far greater, ranging from 0 to greater than 100 percent. For high flows the calculated unit runoff is about 2 times greater than total measured runoff. For low flows the northwest basin of Mirror Lake has the greatest ground water contribution compared to the other two basins. In contrast, Hubbard Brook watershed 3 has the least ground water contribution. 相似文献