摘要:

A new variant of the concordance analysis is developed and discussed in this paper. The concordance procedure in general is a multicriteria evaluation method for alternative projects. It is based on a pairwise comparison of (weighted) project outcomes, and it can be used both as an elimination method for less desirable projects and as a selection method of good projects. The new variant introduced in this paper is based on the idea of satisficing (or norm) project outcomes, which may serve as a frame of reference for the evaluation techniques. Such satisficing outcomes are also important in attacking the dimensional problems of a multicriteria analysis. The new concordance variant is illustrated by means of an empirical application to the selection of the most desirable plan out of a series of alternatives for the development of the Markerwaard area in the Netherlands. It is concluded that the concordance analysis is a useful tool in taking account of intangibles in water resource and land use design.

ISSN:0043-1397    

DOI:10.1029/WR013i003p00513

年代:1977

数据来源: WILEY

摘要:

Implementation of floodplain regulations in the United States has been very slow. There is a danger that regulation will not be widely adopted before floodplains become largely developed. Important among the reasons for failure to regulate floodplains appear to be the misconceptions that precise floodplain delineation is (1) hydrologically possible and (2) legally required. Our analysis shows that wide confidence intervals are unavoidably associated with even the most elaborate and expensive delineation techniques. Application of the ‘fairly debatable rule’ legally supports regulation based on expedient techniques, as long as they are fairly applied, and issues of constitutional purpose and taking of property are properly considered. Thus there is hydrologic and legal justification for floodplain regulation based on expedient delineation methods, and it is imperative that such methods be used if regulation is to be an effective tool for flood damage reduct

ISSN:0043-1397    

DOI:10.1029/WR013i003p00519

年代:1977

数据来源: WILEY

摘要:

Steep unglaciated terrain and a peculiar land use pattern give the upper Mississippi Valley's unglaciated region a distinctive hydrology. Catchments smaller than 250 ha normally have no perennial streams but may have many springs that flow for short distances and then reenter the ground. Land use has been shown to influence the surface hydrology greatly. Tilled cropland is the principal source of flood runoff and stream sediment. Runoff from forest land is minimal regardless of its slope or condition. The occurrence and movement of groundwater are complex, perched water bodies and dry pockets being intermixed with water tables that rise and fall in rapid response to rainfall and snowmelt and in close synchronization with spring flow. Snowmelt produces a distinctive diurnal pattern of both overland flow and groundwater rise, sometimes in midwinter. Overland flow usually peaks about midafternoon and diminishes to near zero a few hours later. The groundwater peak comes early in the morning of the next day. We found little difference in the daily timing of overland flow from north‐ and south‐facing catchments once the melt period had begun. Larger catchments responded to both rainfall and snowmelt much the same as smaller experimental catchme

ISSN:0043-1397    

DOI:10.1029/WR013i003p00524

年代:1977

数据来源: WILEY

摘要:

Sediment rating curves are often used to estimate suspended sediment loads where the sampling program is insufficient to define the continuous record of sediment concentration. Use of this technique will involve errors in the values of sediment load produced, and comparison with measured daily values has been employed by several workers to assess the magnitude of these errors. Comparisons are more difficult for small‐ and medium‐sized catchments because of the general lack of direct measurements of loads. Recording turbidity meters could be employed to provide a continuous record of sediment concentration which can be used to calculate sediment loads. Results are presented for the river Creedy in which the values of sediment load calculated from the continuous concentration record have been compared with estimates derived from rating curves. The rating‐curve data have been grouped according to season and stage tendency to provide various rating relationships. Values of annual sediment load estimated by using a rating curve could involve errors of up to +280%, whereas the errors for monthly loads could range between +900% and −90%. Careful consideration should be given to possible error terms before rating‐curve estimates of sediment load are used in statistical and other

ISSN:0043-1397    

DOI:10.1029/WR013i003p00531

年代:1977

数据来源: WILEY

摘要:

A procedure, recently proposed by the authors to calculate actual evapotranspiration on the basis of parameterization of the atmospheric boundary layer, was applied for the period April through November 1969–1972 with upper air (‘rawinsonde’) meteorological data from Omaha, Nebraska. The accuracy of the 1‐day, 3‐day, weekly, and monthly evapotranspiration totals was assessed by comparing them to evapotranspiration data estimated by a suitable adjustment of potential evapotranspiration from a nearby catchment in the Treynor basins. Several alternative methods for determining the height of the boundary layer and the wind speed at the top of the boundary layer were used; as a result, seven variations of the basic procedure were tested. The similarity functions for water vaporDwere found to be smaller than the corresponding functions for sensible heatCand not equal as was previously assumed. Difficulties were encountered, since published upper air humidity data were in error; nevertheless, the method was reasonably successful on a monthly basis with a correlation coefficient of the order of 0.83 but far less so on a daily basis. The recommended version of the method uses the height of the temperature inversion as an estimate of the boundary layer height and the measured wind as the estimate of the wind speed at the top of the bound

ISSN:0043-1397    

DOI:10.1029/WR013i003p00539

年代:1977

数据来源: WILEY

摘要:

The shape of the hysteretic steady state soil water profile is examined theoretically. It is shown that the hysteretic steady state profile which results after wetting acquires usually minimum values of the soil water pressure head, of the hydraulic conductivity, and of the water content, values smaller than the asymptotic values approached at large heights. In contrast, the hysteretic steady state profiles which result after drying do not show such minimum values. Experimental hysteretic steady state profiles established in a vertical sand column confirm the theoretical predictions and are in agreement with those calculated numerically from the flow equation. The importance of the hysteresis for soil water retention and movement is discussed.

ISSN:0043-1397    

DOI:10.1029/WR013i003p00549

年代:1977

数据来源: WILEY

摘要:

The equations governing the flow of fluid through fractured porous media are derived. These equations consist of Darcy's law for fluid flow in the primary pores, equations of motion for fluid flow in the fractures, and two continuity equations. The system of equations is coupled by the interaction of fluid in the primary pores with fluid in the fractures. The coupling terms, which are incorporated in the continuity equations, describe the transient flux of fluid out of the primary pores and into the fractures. The finite element Galerkin method is used to solve this coupled system of equations for transient flow in a confined leaky aquifer. Solutions are obtained for both constant discharge and step drawdown problems. The importance of coupling the primary blocks to the fracture system and the effect of the acceleration term in the equation of motion in the fractures are studied by using this model.

ISSN:0043-1397    

DOI:10.1029/WR013i003p00558

年代:1977

数据来源: WILEY

摘要:

Box‐Jenkins modeling of time series data can be improved and simplified by adhering to contemporary modeling procedures. This paper gives the theory and techniques of the application of many recent advances that have been made at the identification, estimation, and diagnostic check stages of model development. The inverse autocorrelation function and the inverse partial autocorrelation function are demonstrated to be useful identification tools for both nonseasonal and seasonal models. Parameters can be estimated more efficiently by employing the modified sum of squares technique. At the estimation stage it is also possible to obtain a maximum likelihood estimate for a Box‐Cox power transformation. The Akaike information criterion is introduced to formalize mathematically the concept of model parsimony. When checking for model adequacy, knowing the distribution of the residual autocorrelation allows for a sensitive test for residual whiteness. Diagnostic checks are given for verifying the assumption of homoscedasticity of the model residuals. In practice, heteroscedasticity and nonnormality of the residuals can often be removed by a Box‐Cox transform

ISSN:0043-1397    

DOI:10.1029/WR013i003p00567

年代:1977

数据来源: WILEY

摘要:

Recent Box‐Jenkins techniques are employed to determine both nonseasonal and seasonal models for actual time series. The applied examples are carefully explained in order to demonstrate the utility of the new procedures that have been developed for use at the identification, estimation, and diagnostic check stages of model development. Even though more methods are now available for model building, it is demonstrated that this fact enhances rather than complicates the model construction phases. Furthermore, for all three applications considered, better models are obtained than it was previously possible to obtain. A new technique is described for optimal forecasting of the original time series when the data have been transformed by a nonlinear transformatio

ISSN:0043-1397    

DOI:10.1029/WR013i003p00577

年代:1977

数据来源: WILEY

摘要:

In the practical application of many methods of flood hydrograph synthesis it is necessary to space isochrones of travel time over the watershed or to allocate the distribution of storage. The available evidence for guiding this procedure is reviewed, but most information applies to large stream systems and to flows lower than the flood discharges of interest. Times of travel data from tracing of flood runoff on a small watershed have been compared with the evidence from large streams. Average velocities were found to increase slightly in a downstream direction through the watershed, despite decreasing slope. This increase conforms with published hydraulic geometry relationships. Five geomorphological parameters have been tested as methods for spacing isochrones. Field inspection to determine mean depths, and possibly roughness, at bank‐full stages should lead to greatest accuracy, but simple parameters based on stream length also gave good result

ISSN:0043-1397    

DOI:10.1029/WR013i003p00587

年代:1977

数据来源: WILEY