首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 11 毫秒
1.
Study of water resource decision-making in Massachusetts demonstrates the existence of many institutional constraints such as the established fee system for consulting engineers, the funding of certain agencies, the institutionalization of equity concerns, overrepresentation of interests, and incompatibility of agency goals. These institutional constraints are attributable in part to certain broadly-based value-orientations such as the American pragmatic tradition. However, various lines of evidence indicate that these constraints are less important than other factors in the etiology of decisional outcomes. The outcomes of the decision processes were found to be at variance with the decisions studied, a fact leading to the conclusion that choice of decisions for study should be given more attention. The authors conclude that institutional constraints are important if one is interested in studying how decisions are made, but that what actually happens in the long run cannot be easily ascertained by studying either institutions or the decision-making process. They suggest the need for more research utilizing the incremental theories of Carl Lindblom and the side-effect theories of Albert O. Hirschman.  相似文献   

2.
ABSTRACT. In the past planners have used various approaches to develop alternative plans for planning studies. These include: rational thought which draws upon the planners' knowledge, experience and judgement; objectives which emphasize specific values such as economic and environmental; technologies which achieve the same objective; public preferences which reflect public values and interests; alternative futures which array a diverse range of possible futures; mathematical models which rapidly evaluate possible alternatives; cost sharing policies which consider a participant's financial interest; Delphi technique utilizing a diversity of professional expertise; the IDEA method which stimulates and evaluates large numbers of alternatives. Most of these approaches have found application on various planning studies.  相似文献   

3.
ABSTRACT: An environmental simulation model of the Upper St. Johns River Basin, Florida, has been developed in order to predict hydrologic responses under proposed management plans. Land use projections for each of 19 hydrologic planning units are provided by a linear programming analysis of agricultural activities. Inputs to the model include rainfall, runoff, evapotranspiration (ET), aquifer properties, topography, soil types, and vegetative patterns. A water balance is developed in the uplands based on infiltration, ET, surface runoff, and groundwater flow. Valley continuity is based on stage-volume relationship for inflows and outflows and a variable roughness coefficient dependent on vegetative patterns. Land use changes form the basis for predicting hydroperiod variation under alternative management schemes. Plans are ranked according to two criteria, deviation from a natural hydroperiod and flood or drought control provided. Results indicate that (1) a single reservoir without irrigation and (2) floodplain preservation plans are superior to (3) multiple reservoir with irrigation and (4) uncontrolled floodplain plans with regard to both criteria.  相似文献   

4.
ABSTRACT: A modeling framework was developed for managing copper runoff in urban watersheds that incorporates water quality characterization, watershed land use areas, hydrologic data, a statistical simulator, a biotic ligand binding model to characterize acute toxicity, and a statistical method for setting a watershed specific copper loading. The modeling framework is driven by export coefficients derived from water quality parameters and hydrologic inputs measured in an urban watershed's storm water system. This framework was applied to a watershed containing a copper roof built in 1992. A series of simulations was run to predict the change in receiving stream water chemistry caused by roof aging and to determine the maximum copper loading (at the 99 percent confidence level) a watershed could accept without causing acute toxicity in the receiving stream. Forecasting the amount of copper flux responsible for exceeding the assimilation capacity of a watershed can be directly related to maximum copper loadings responsible for causing toxicity in the receiving streams. The framework developed in this study can be used to evaluate copper utilization in urban watersheds.  相似文献   

5.
ABSTRACT: Nine flood-estimation models used for ungauged urban watersheds in Louisiana were evaluated. Flood-quantile predictions from simple regression models calibrated by local data were found to be more reliable than those more complicated models or models with many parameters that may not be accurately estimated. Flood prediction from models developed by using regionalization techniques were found to be reasonably good. Finally, application of a model outside of its limitations or domain may lead to substantial prediction error.  相似文献   

6.
ABSTRACT: Water quality and nonpoint source (NPS) pollution are important issues in many areas of the world, including the Inner Bluegrass Region of Kentucky where urban development is changing formerly rural watersheds into urban and mixed use watersheds. In watersheds where land use is mixed, the relative contributions of NPS pollution from rural and urban land uses can be difficult to separate. To better understand NPS pollution sources in mixed use watersheds, surface water samples were taken at three sites that varied in land use to examine the effect of land use on water quality. Within the group of three watersheds, one was predominately agriculture (Agricultural), one was predominately urban (Urban), and a third had relatively equal representation of both types of land uses (Mixed). Nitrogen (N), phosphorus (P), total suspended solids (TSS), turbidity, pH, temperature, and streamflow were measured for one year. Comparisons are made among watersheds for concentration and fluxes of water quality parameters. Nitrate and orthophosphate concentrations were found to be significantly higher in the Agricultural watershed. Total suspended solids, turbidity, temperature, and pH, were found to be generally higher in the Urban and Mixed watersheds. No differences were found for streamflow (per unit area), total phosphorus, and ammonium concentrations among watersheds. Fluxes of orthophosphate were greater in the Agricultural watershed that in the Urban watershed while fluxes of TSS were greater in the Mixed watershed when compared to the Agricultural watershed. Fluxes of nitrate, ammonium, and total phosphorus did not vary among watersheds. It is apparent from the data that Agricultural land uses are generally a greater source of nutrients than the Urban land uses while Urban land uses are generally a greater source of suspended sediment.  相似文献   

7.
ABSTRACT: A representative city in an arid zone, such as the Kingdom of Saudi Arabia, is instrumented to determine the quantity and quality of storm runoff with a view to investigating the possibility of using it for industrial and agricultural purposes after appropriate treatments. In an urban watershed in the City of Dhahran, Saudi Arabia, quantity and quality of storm runoff had been monitored for the past six years, and the average annual runoff that can be harvested was determined. The quality of runoff is well within the range of possible reuse schemes, most notably for restricted irrigation. Treatment schemes for the harvested water are proposed.  相似文献   

8.
ABSTRACT: Hydraulic geometry relationships, or regional curves, relate bankfull stream channel dimensions to watershed drainage area. Hydraulic geometry relationships for streams throughout North Carolina vary with hydrology, soils, and extent of development within a watershed. An urban curve that is the focus of this study shows the bankfull features of streams in urban and suburban watersheds throughout the North Carolina Piedmont. Seventeen streams were surveyed in watersheds that had greater than 10 percent impervious cover. The watersheds had been developed long enough for the streams to redevelop bankfull features, and they had no major impoundments. The drainage areas for the streams ranged from 0.4 to 110.3 square kilometers. Cross‐sectional and longitudinal surveys were conducted to determine the channel dimension, pattern, and profile of each stream and power functions were fitted to the data. Comparisons were made with regional curves developed previously for the rural Piedmont, and enlargement ratios were produced. These enlargement ratios indicated a substantial increase in the hydraulic geometry for the urban streams in comparison to the rural streams. A comparison of flood frequency indicates a slight decrease in the bankfull discharge return interval for the gaged urban streams as compared to the gaged rural streams. The study data were collected by North Carolina State University (NCSU), the University of North Carolina at Charlotte (UNC), and Charlotte Storm Water Services. Urban regional curves are useful tools for applying natural channel design in developed watersheds. They do not, however, replace the need for field calibration and verification of bankfull stream channel dimensions.  相似文献   

9.
ABSTRACT: Abundant use of copper based products has resulted in increased violation of copper water quality criteria in runoff from urban storm water systems. The objectives of this work were to understand the mobility and toxicity of copper in an urban watershed and to apportion the amount of copper entering the freshwater receiving stream from different urban land covers using a mass balance approach. Sixteen rainfall events collected from the University of Connecticut study watershed between August 1998 and September 2000 were analyzed to assess copper flux in an urban storm water system. Mean flow weighted dissolved copper concentrations observed in the study for copper based architectural material runoff, pervious area runoff, impervious area runoff, and in the receiving stream were 1210 ± 840, 9 ± 3, 8 ± 2, and 14 ± 7 μg/L, respectively. Mean dissolved copper concentrations in the receiving stream exceeded Connecticut's water quality criteria. Despite exceeding the dissolved concentration based criteria, cupric ion concentrations at the system outlet remained below 0.05 μg/L for all storms analyzed, and no acute toxicity (using Daphnia pulex as the test organism) was measured in samples collected from the stream.  相似文献   

10.
ABSTRACT: There is considerable controversy inthe Northeast surrounding the extent to whcih public drinking water reservoirs should be used for recreational purposes. This paper reports the results of two integrated studies of (1) recreation users of Quabbin Reservation, the largest inland water source in New England and (2) the general public of Massachusetts. Data were obtained by conducting on-site interviews of Quabbin users and through state-wide telephone interviews of the general public; both studies focused on assessing attitudes toward the recreational use of drinking water reservoirs in Massachusetts. Unlike the findings of a 1969 study conducted by Baumann, results showed that the majority of Massachusetts residents do not favor recreation-prohibiting laws for most activities. Most favored at least moderate use of reservoirs for recreational purposes. In addition, over all views were not as restrictive as present legislation would suggest. Finally, these findings suggest that current recreation-prohibiting laws should be reassessed in light of pugblic opinion which favors the use of these valuable resources.  相似文献   

11.
ABSTRACT: This paper reports on the development of a mathematical model for forecasting energy development in the Yellowstone study area for the years 1985 and 2000, and determining the associated economic demands for water, land, labor, capital, and mineral resources. The study was prepared for use by the Missouri River Basin Commission in conducting a comprehensive, “Level B” planning study of the water and related land resources in the Yellowstone River Basin. The study results indicate that the amount of coal development in the Yellowstone study area will depend primarily upon state and federal energy policies and regulations. Policies related to slurry pipeline transportation of coal will be particularly important in determining the level and pattern of future energy development in the area. Coal production under the “most probable” scenario is expected to increase from about 40 million tons in 1976 to 163 million tons per year by 1985, and 513 million tons in the year 2000. Consumptive water use for energy development in the study area could be as much as 556,000 acre-feet per year by the year 2000 (under the high scenario). A parametric analysis was conducted on the 1985 most probably scenario to determine the influence on the study results of variations in the delivered price of water. Water requirements were reduced by nearly one-fourth as water costs increased from zero to over $750 per acre-foot.  相似文献   

12.
ABSTRACT: A general model of the policy implementation process is utilized to facilitate a discussion of the way Section 208 of PL 92-500 is being carried out on an areawide basis. A study of four “208 areas” in the “New York-Philadelphia corridor” highlights the operation of several variables used in the model. The varying political and socioeconomic conditions in geographic areas which have similar water quality problems are leading to the evolution of vastly different implementing structures, or institutional arrangements. The analysis suggests that these differences may have important implications for the success of the program in each of these areas. A major underlying theme is that such problems are characteristic of the 208 process nationwide and reflect general difficulties associated with managing water quality in a federal system.  相似文献   

13.
ABSTRACT: An analogue method of ex post evaluation is proposed as a method of measuring the effectiveness of small watershed projects in obtaining flood control and economic benefits. Two watersheds were compared on a “with vs. without” project basis by both direct and indirect measurement of economic benefits. Direct measurements indicated that small watershed flood control projects did not generate the expected economic benefits. However, the indirect measurements of the same watersheds using land value enhancement as a surrogate suggested that the expected economic benefits were reflected in differential land values. The economic efficiency of small watershed projects should be measured ex ante and ex post on a “with vs. without” project basis rather than on a “before vs. after” basis whether using direct or surrogate variables.  相似文献   

14.
ABSTRACT: Water is, and most likely will continue to be, one of the main concerns and potential causes of instability in the Middle East (ME). The contribution of the existing renewable water resources is limited and can not fulfill the long-term projected gap between water supply and demand for most of the countries in the ME. An integrated regional approach for fulfilling this gap was preferred. A regional institutional framework was proposed for the implementation of this integrated regional approach and consists of a regional water board operating through three units for technical, implementation, and management aspects of project and activities. An analysis of the regional water supply and demand development, the design and policy making of the proposed institution, technology and water markets, cooperation, actors and beneficiaries, finances, and expected obstacles and constraints to the establishment and sustainable operation of the proposed institution are included.  相似文献   

15.
Abstract: Natural channel designs often incorporate rigid instream structures to protect channel banks, provide grade control, promote flow deflection, or otherwise improve channel stability. The long term impact of rigid structures on natural stream processes is relatively unknown. The objective of this study was to use long term alluvial channel modeling to evaluate the effect of rigid structures on channel processes and assess current and future stream channel stability. The study was conducted on Oliver Run, a small stream in Pennsylvania relocated due to highway construction. Field data were collected for one year along the 107 m reach to characterize the stream and provide model input, calibration, and verification data. FLUVIAL-12 was used to evaluate the long term impacts of rigid structures on natural channel adjustment, overall channel stability, and changing form and processes. Based on a consideration of model limitations and results, it was concluded that the presence of rigid structures reduced channel width-to-depth ratios, minimized bed elevation changes due to long term aggradation and degradation, limited lateral channel migration, and increased the mean bed material particle size throughout the reach. Results also showed how alluvial channel modeling can be used to improve the stream restoration design effort.  相似文献   

16.
Abstract: A primary water quality problem caused by non-point source pollution (NPSP) is eutrophication, from excess nutrients in receiving water bodies. The control of nutrients arising from NPSP is difficult because the source areas can be hard to identify and typical treatment methods are infeasible due to the distributed nature of the pollutants. It may be possible to reduce nutrient related water quality problems through the restoration of highly disturbed watersheds with best management practices (BMPs). While restoration attempts may provide significant returns, they can be costly to implement and often are met with resistance in agricultural communities. Extending model results beyond the range of calibration to model future conditions such as for restoration scenarios requires the use of physically-based models that include the important processes that generate streamflow and material transport, uptake, loss, transformation, and recycling of nutrients and other material. The research and development objectives of the US. Army Engineer Research and Development Center (ERDC) in Vicksburg, Mississippi, are to develop a watershed assessment and management model to simulate transport, uptake, loss, transformation, and recycling of nutrients such as nitrogen and phosphorus and associated material such as sediment and organic matter. In this study we will discuss current efforts at the ERDC's Environmental Laboratory to develop a state-of-the-art watershed water quality model.  相似文献   

17.
ABSTRACT: Attitudinal surveys of residents living near four small residential lakes were conducted to determine how they perceived the advantages and disadvantages associated with the lakes. The survey results indicate that lakes can be used as a tool for land development creating a variety of benefits and problems. Most people felt that lakes have a positive economic impact on the value of their home, are a positive factor in their decision to purchase a home, and provide them with some benefits. They were also aware that lakes create continual maintenance and water quality problems but were willing to pay for the maintenance if they had access to and could utilize the facilities associated with the lakes. Based on the results of the surveys, recommendations are formulated pertaining to the planning development and utilization of residential lakes.  相似文献   

18.
ABSTRACT: While federal water resources laws and regulations require social analysis, no one workable formula exists for integrating it into water resources planning. Two primary problems in integrating social analysis into planning are examined; making trade-offs between policy acceptability and theoretical competence, and managing social analysis in planning. For illustration, the article builds on emerging trends within the U.S. Army Corps of Engineers. It concludes by observing that creative application of social theory to policy problems along with innovative data gathering techniques are the primary routes to managing these problems.  相似文献   

19.
ABSTRACT: Ground-water level decline patterns in parts of Nebraska conform to the circular island concept of Bredehoeft et al. (1982), which indicates how water is derived by wells developed in a circular island. If elongated, the center of the island corresponds to a regional ground-water divide while the shoreline corresponds to a regional river. In both versions, ground-water table elevation is a function of recharge and transmissivity. A dynamic equilibrium exists such that the gradient of the water table will convey all recharge to discharge areas. Withdrawals of ground water result initially in mining, with a new equilibrium attained when pumping equals capture. During early development, capture is an important source of water in discharge areas, while mining is more significant in recharge areas. The pattern observed in many areas shows the greatest ground-water level decline in the vicinity of ground-water divides and the steepest gradient near regional rivers. A similar pattern has been observed adjacent to the Arkansas River in south-central Kansas. Similar decline patterns can be modeled for a hypothetical ground-water basin. This is of major importance to water-resource managers because it dictates that management programs be applied to the entire hydrologic system.  相似文献   

20.
ABSTRACT: Recent Federal and some State legislation has enlarged the scope of permitted or required actions of local units of government in water resources management and protection. Much of the legislation encourages local units of government to introduce water resources planning measures which will be preventive instead of corrective. Extensive public works measures, environmental destruction and the threat to human life can thus be eliminated or reduced. Research has developed and tested a method for identifying the elements of a water resources protection program for small urbanizing watersheds which was technically adequate and socially acceptable to the communities implementing such programs. Research results suggest that deliberate efforts will be necessary to inform and educate local units of government as to the usefulness of the legislation; and that the program must reflect local natural resource conditions and local preferences for the method of accomplishing the protection. Successful implementation could be restrained by inertia of local units of government, a lack of tradition in such programs, and hostile existing agencies.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号