摘要:

The economic benefits of developing and improving small boat harbors has traditionally been estimated by use of what has come to be known as the small boat formula (SBF), a method which has many theoretical and practical defects. In this paper these limitations are detailed, and alternative approaches to the SBF are outlined and evaluated. These alternatives represent different ways of estimating what is, in principle, a correct benefits measure based on economic surplus. Suggestions for implementing the recommended procedures are provided.

ISSN:0043-1397    

DOI:10.1029/WR021i009p01303

年代:1985

数据来源: WILEY

摘要:

The use of cost‐benefit analysis to evaluate the net welfare payoffs from water projects has now been an established practice for many years. One of the interesting aspects of such cost‐benefit studies is that water projects involve an uncertain flow of costs and benefits, arising from the stochastic nature of streamflows. Hence a basic problem for the cost‐benefit analyst is that of incorporating this uncertainty into his measures of costs and benefits. In the present paper we examine the problem of computing an appropriate consumer surplus measure to evaluate water project benefits under uncertainty. Detailed treatment is given to the case in which a complete set of contingent claim markets exists in the economy as well as to the case of a spot market economy. The consumer surplus measure applicable to the contingent claim economy is a simple generalization of the measure that applies to a world of certainty, but in the case of a spot market economy there is an unobserved component of consumer benefits that limits the applicability of the usual consumer surplus me

ISSN:0043-1397    

DOI:10.1029/WR021i009p01307

年代:1985

数据来源: WILEY

摘要:

A new procedure was formulated to predict and monitor the cumulative impacts of projects requiring Corps of Engineers permits. To evaluate the effectiveness of this new assessment approach, hypotheses describing relationships between an independent variable, use of the cumulative impact assessment approach, and nine dependent variables were developed. A quasi‐experiment, in which the cumulative impact assessment approach was the treatment, was conducted to determine how the approach influenced the permit review process. The evaluation procedure was applied to the test implementation of the cumulative impact assessment approach at the San Francisco District. Measures and scoring procedures were devised and data were collected and analyzed. Conclusions regarding the new approach were drawn along with suggestions for improvements to the evaluation procedur

ISSN:0043-1397    

DOI:10.1029/WR021i009p01313

年代:1985

数据来源: WILEY

摘要:

An analysis is done of the costs imposed on participants in the electricity market arising from irrigation diversions from the Columbia River. The hypotheses analyzed are (1) that electricity consumers' welfare is not affected by irrigation diversions, (2) that hydropower loss estimates derived using time and location specific data do not differ from those derived using average data, (3) that water year does not affect welfare losses, (4) that demand elasticity does not affect welfare losses, (5) that farmer pumping payments do not affect welfare losses, and (6) that interruption of water in critical flow years does not affect welfare losses. Electricity consumers are found to lose welfare when diversions are increased. Considering a potential diversion in central Washington, the annual loss to electricity consumers is in excess of $100 per acre ($247/hectare) developed. When the government delivers water to farmers' fields, this loss exceeds $200 per acre ($584/hectare). A sensitivity analysis of the welfare loss estimates shows that they are sensitive to the share that diverters pay of pumping costs and the potential interruption of diversions but not to different hydropower loss estimates, demand elasticity and water year. The results under critical water year interruption show a potential for reducing the tradeoffs between irrigation development and hydroelectric power generation as the costs fall by almost 80%.

ISSN:0043-1397    

DOI:10.1029/WR021i009p01319

年代:1985

数据来源: WILEY

摘要:

Estimates of financial and economic net benefits to irrigation water supply are shown for a case study area in the northern Nile delta region of Egypt. Linear programming models of representative farms in the study area are formulated with particular attention to the possibilities of using less water per crop as well as shifting crops in response to hypothetical reductions in water supply. Net benefits are defined as gross revenues minus costs of production, including an imputed charge for family labor. Model solutions are based on both 1980 government prices with production controls (financial net benefits) and hypothetical 1980 international market prices with relaxed controls (economic net benefits). Five different water supply scenarios are analyzed: from the current, adequate level of supply, down to a 40% reduction from that level. Total, average, and marginal net benefit functions are reported. Implications of the differences between the financial and economic benefit functions for farmers are discussed.

ISSN:0043-1397    

DOI:10.1029/WR021i009p01329

年代:1985

数据来源: WILEY

摘要:

Data from eight evaporation pans containing brines of different salinity and ionic composition were analyzed to quantify the effect of salinity on evaporation. The common procedure of correcting fresh water evaporation by an empirical ratio (α) of salt water to fresh water evaporation rates is shown to be only approximate. A more accurate approach based on the effect of salinity on saturation vapor pressure is described. The activity coefficient of water (β) was computed based on the pan evaporation data. Various analytical methods to compute the effect of salinity on saturation vapor pressure based on ionic composition of the solution are described and applied with Dead Sea data. These approaches can be applied in many engineering applications including water balance calculations for saline lakes, salt production ponds, and evaporation ponds used for disposal of saline effluent

ISSN:0043-1397    

DOI:10.1029/WR021i009p01336

年代:1985

数据来源: WILEY

摘要:

An asymptotic, one‐dimensional Green‐Ampt model of infiltration into a soil containing regularly spaced vertical cracks, or a cylindrical soil column containing a central hole, is derived from a complete two‐dimensional or axisymmetric Green‐Ampt analysis by summing an asymptotic expansion for the infiltration rate valid at large times when the wetting front has become horizontal. The model is shown to be accurate at intermediate times when the front is not necessarily horizontal and corresponds to one‐dimensional infiltration initiated from a plane lying below the soil surface at a depth which depends only on the geometry and which lies between zero and the crack (hole) depth. When applicable, model predictions of infiltration rate and cumulative infiltration obtained for cylindrical holes, like those previously obtained for cracks, agreed well with corresponding results based on finite difference solutions of the saturated‐unsaturated flow equations, differences being in the ra

ISSN:0043-1397    

DOI:10.1029/WR021i009p01345

年代:1985

数据来源: WILEY

摘要:

A new numerical method called the finite analytic (FA) method is used to solve a groundwater solute transport problem. The basic idea of the finite analytic method is the incorporation of local analytic solution in the numerical solution of the partial differential equation. When the local analytic solution is evaluated at a given nodal point, it gives an algebraic relationship between a nodal value in an element and its neighboring nodal points. The assemble of the linear system equations results in a tridiagonal matrix. Like most finite difference method, the advantages of using efficient iterative techniques for solving tridiagonal matrices are equally applicable to FA method. The automatic localized upstream shift and the analytic property of the FA method eliminates the difficulty of numerical dispersion locally and suppresses the overall numerical dispersion for large Peclet number. For small Peclet number FA method yields excellent results in comparison with the analytic solution. For large Peclet number FA solutions are oscillation free with some degree of numerical dispersion. The results are comparable with those obtained using upstream weighted finite element method.

ISSN:0043-1397    

DOI:10.1029/WR021i009p01354

年代:1985

数据来源: WILEY

摘要:

Equilibrium sorting of coarse mobile bed load sediment in meander bends is considered. A theory of two‐dimensional bed load transport of graded material, including the effects of gravity on lateral slopes and secondary currents, is developed. This theory is coupled with a simple treatment of flow in bends, an analytically determined bend shape, and the condition of continuity of each grain size range in transport to describe sorting. The theory indicates that the locus of coarse sediment shifts from the inside bank to the outside bank near the bend apex, as is observe

ISSN:0043-1397    

DOI:10.1029/WR021i009p01361

年代:1985

数据来源: WILEY

摘要:

In lake liming operations in Sweden, acidified lakes are reclaimed by neutralization with calcite powder. The amount added is intended to neutralize the water column as well as to delay the reacidification. The reacidification of limed lakes is dependent on the dilution of the dissolved calcium carbonate with time and, for a limited period of time, the dissolution of calcite from the lake sediments. Calcite on the lake bottom will, in addition to being covered by sedimentation, become inactivated by precipitates of humus and clay minerals clogging the calcite surfaces. A model has been developed to calculate the reacidification of a limed lake which includes the following mechanisms: (1) the dissolution of calcite and a subsequent neutralization of acid water, (2) owing to the increase inpH value, occurrence of precipitation of humus and dissolved metals onto the calcite surface and inhibition of the dissolution of calcite (3) reversible sorbtion of calcium from the water column by sediments not covered with calcite, and (4) diffusive transport through a boundary bottom layer to the water column. In a first approach the lake was modeled as a continuously stirred tank. The equations were derived from a mass balance and the dissolution kinetics for calcite to describe the long‐term development ofpH, alkalinity, and calcium concentration in the lake. The differential equations describing the mechanisms were solved with the help of a computer code. The model accurately describes the reacidification and the mass balances observed in several limed lake

ISSN:0043-1397    

DOI:10.1029/WR021i009p01374

年代:1985

数据来源: WILEY