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1.
ABSTRACT: This paper defines types of water losses in irrigated agriculture and outlines potentials for water conservation. Recoverable water “losses” (seepage, leakage, and spillage during storage and conveyance, and surface runoff and deep percolation during irrigation) and irrecoverable losses (evaporation from water and soil surfaces and transpiration from plants) are described and illustrated. Some conservation terms are defined, particularly the distinction between on-farm irrigation efficiency and areawide efficiency. Briefly reviewed are agricultural water conservation technologies and their applicability. The biggest untapped potential for water conservation may be a reduction in irrecoverable losses, especially evapotranspiration. The advantages and disadvantages of reducing recoverable and irrecoverable water losses are described, including possible effects on ground water, energy, salinity, crops, wildlife, and in-stream uses. Such information may be useful in several policy and management issues, e.g., ground water overdraft and possible constraints on crops and sites to be irrigated.  相似文献   

2.
ABSTRACT: Water management in the United States has historically been characterized by a decisionmaking system that is fragmented along three dimensions: (1) physical, (2) institutional, and (3) political-technical. The result is often ‘garbage can’ decision-making in open decisionmaking structures with the attributes of an ‘organized anarchy’ rather than the rational, comprehensive decisionmaking prescribed for water management. A case study of water quality management decisionmaking in the New York Finger Lakes is used to illustrate how the garbage can model can illuminate the forces that operate in fragmented water management. Interorganizational decisionmaking theory and experience from water management integration initiatives are then applied to assess what strategies may be effective in reducing the organizational anarchy that results from fragmented water management institutions.  相似文献   

3.
Best management practices (BMPs) play an important role in improving impaired water quality from conventional row crop agriculture. In addition to reducing nutrient and sediment loads, BMPs such as fertilizer management, reduced tillage, and cover crops could alter the hydrology of agricultural systems and reduce surface water runoff. While attention is devoted to the water quality benefits of BMPs, the potential co‐benefits of flood loss reduction are often overlooked. This study quantifies the effects of selected commonly applied BMPs on expected flood loss to agricultural and urban areas in four Iowa watersheds. The analysis combines a watershed hydrologic model, hydraulic model outputs, and a loss estimation model to determine relationships between hydrologic changes from BMP implementations and annual economic flood loss. The results indicate a modest reduction in peak discharge and economic loss, although loss reduction is substantial when urban centers or other high‐value assets are located downstream in the watershed. Among the BMPs, wetlands, and cover crops reduce losses the most. The research demonstrates that watershed‐scale implementation of agricultural BMPs could provide benefits of flood loss reduction in addition to water quality improvements.  相似文献   

4.
ABSTRACT: A severe sustained drought in the Colorado River Basin would cause economic damages throughout the Basin. An integrated hydrologic-economic-institutional model introduced here shows that consumptive water users in headwaters states are particularly vulnerable to very large shortfalls and hence large damages because their rights are effectively junior to downstream users. Chronic shortfalls to consumptive users relying on diversions in excess of rights under the Colorado River Compact are also possible. Nonconsumptive water uses (for hydropower and recreation) are severely affected during the worst drought years as instream flows are reduced and reservoirs are depleted. Damages to these uses exceeds those to consumptive uses, with the value of lost hydropower production the single largest economic impact of a severe sustained drought. Modeling of alternative policy responses to drought suggests three general policy approaches with particular promise for reducing damages. Consumptive use damages can be reduced by over 90 percent through reallocation from low to high valued uses and through reservoir storage strategies which minimize evaporation losses. Reservoir management to preserve minimum power pool levels for hydropower production (and to maintain reservoir recreation) may reduce damages to these nonconsumptive uses by over 30 percent, but it may increase consumptive use shortfalls.  相似文献   

5.
We present a risk-based contingency fund management methodology to mitigate the impact of external risks on asset value and performance. Many asset intensive industries, such as water and energy utilities, are significantly affected by external risks such as extreme weather events. We put the case for a centrally held risk-based contingency fund that would mitigate against ‘medium’ impact ‘medium’ probability events that fall outside of large losses covered by insurance and smaller ‘normal’ operating losses. Our risk-based contingency approach is appropriate for short-term business planning (1–5 years) and would complement longer term planning, for example climate change adaptation and mitigation strategies. Our approach offers a risk-based methodology to manage contingency that is explicit and defensible. Critically, our methodology allows contingency to be managed dynamically as risk probabilities and impacts change, creating a mechanism for contingency funds to be periodically released if risk exposure reduces. The long-term benefit of dynamic, risk-based contingency is to reduce the impact of external risks and support long-term sustainability.  相似文献   

6.
Water transfers from agricultural to urban and environmental uses will likely become increasingly common worldwide. Many agricultural areas rely heavily on underlying groundwater aquifers. Out-of-basin surface water transfers will increase aquifer withdrawals while reducing recharge, thereby altering the evolution of the agricultural production/groundwater aquifer system over time. An empirical analysis is conducted for a representative region in California. Transfers via involuntary surface water cutbacks tilt the extraction schedule and lower water table levels and net benefits over time. The effects are large for the water table but more modest for the other variables. Break-even prices are calculated for voluntary quantity contract transfers at the district level. These prices differ considerably from what might be calculated under a static analysis which ignores water table dynamics. Canal-lining implies that districts may gain in the short-run but lose over time if all the reduction in conveyance losses is transferred outside the district. Water markets imply an evolving quantity of exported flows over time and a reduction in basin net benefits under common property usage. Most aquifers underlying major agricultural regions are currently unregulated. Out-of-basin surface water transfers increase stress on the aquifer and management benefits can increase substantially in percentage terms but overall continue to remain small. Conversely, we find that economically efficient management can mitigate some of the adverse consequences of transfers, but not in many circumstances or by much. Management significantly reduced the water table impacts of cutbacks but not annual net benefit impacts. Neither the break-even prices nor the canal-lining impacts were altered by much. The most significant difference is that regional water users gain from water markets under efficient management.  相似文献   

7.
Natural resource industries are increasingly significant actors in environmental decision-making. Possessing vast institutional and technical capacity, firms have an important role to play in ‘new’ governance strategies such as collaboration. These strategies are often based upon assumptions of equitable influence. This paper investigates the nature of resource industry participation in collaborative water governance in Canada, and the potential consequences of that participation as investigated using power theory. The study used comparative cases to reveal that resource industries are able to shape collaboration, and the issues collaborated upon, at multiple analytical levels both internal and external to the collaborative process in ways not available to other actors. Analysis also revealed that resource industry participation in collaboration did not reflect a commitment to engage in shared learning and the reexamination of values and interests as presupposed by collaborative theory. Collaboration is thus challenged in producing equitable, representative outcomes when resource industries participate.  相似文献   

8.
Management of fresh water resources meets a range of often conflicting interests. Waterways usually run across political and administrative borders and hence make management difficult and collective action politically challenging. In order to meet these challenges, multi-level bioregional approaches to water management have been called for. Such an approach is institutionalised in the EU's Water Framework Directive (WFD). This paper presents the experiences of the Morsa water sub-district in southern Norway, a pilot for implementing the WFD. The paper discusses Morsa in the light of four principles for multi-level water governance: management on a bioregional scale; polycentric governance; public participation; and an experimental approach to water governance. Contrary to widely held assumptions that collective action in polycentric networks will be difficult because actors will follow their own narrow interests, the findings demonstrate how this is not an absolute truth, and how social action cannot be fully explained by rational action theories. The analysis concludes that the relative success of Morsa relates to a complex of factors, including openness of practices and active involvement of key actors, strong but including leadership, and a knowledge based ‘hybrid’ type of multi-level network combining horizontal and vertical network governance.  相似文献   

9.
The 2016 US Presidential Campaign of Donald J. Trump described renewing ‘America’s crumbling infrastructure’ with an extensive program for transportation, water, power grids, telecommunications, security, and other facilities. The program includes incentive-based contracting, jobs creation that leads to increased tax revenues, and attention to reducing waste in procurement. This editorial outlines how key differences between campaigning and governance can affect Presidential transitions for areas such as developing infrastructure policy. The editorial then outlines strategies that can assist with the selection and implementation of infrastructure improvement projects for the Trump Administration moving forward.  相似文献   

10.
Incorporation of environmental flow releases from reservoirs has proven to be challenging due to fear of losses to existing water uses. Moreover environmental flow requirements (EFR) have not often been operationalized. This study compares the possibility of implementing dynamic EFR based on natural flows lagged against an upstream unregulated gauging point with static EFR. It simulates different scenarios with a high flow release in the wet season and analyses its impacts on hydropower production. This method accounts fully for the natural variability of environmental flows, implying less pressure on existing water uses during relatively dry years. Joint operation of two cascading dams vs. individual operation for EFR was also explored. These approaches were tested for the Zambezi River basin in Southern Africa using a water resources model, WAFLEX. Historic data on reservoir water levels, releases and power generation of the hydropower schemes were synthesized. Combining these yielded a validated series of monthly flow data for a 28 year period (1982‐2010). The results show that Kariba and Cahora Bassa reservoirs face a reduction in power produced when they would annually release an environmental flow. However, the dynamic EFR method entails smaller hydropower losses. Joint environmental flow operations will reduce overall basin power production more than if Cahora Bassa alone would release an environmental flow. However, such joint operation would be more beneficial to the ecosystem.  相似文献   

11.
Community participation, ownership and cost sharing are key components of Tanzania's water policy, in common with the broad international consensus on water governance. However these policy goals are difficult to achieve, beset with paradoxes and their benefits may be overstated, both in terms of efficiency of resource management and equality of outcomes. This article draws on longitudinal ethnographic research of a village water supply in Tanzania to explore two issues: the contested nature of community ownership and the complex evolution of a ‘community‐owned’ institution. The evidence from the Uchira Water Users Association leads us to question some of the simplistic assumptions made concerning the capacity of local communities to manage service delivery and to balance equity and sustainability principles. The limitations of ‘bottom‐up’ and demand led approaches need to be recognised without discrediting their potential for challenging inequalities. The article concludes with a consideration of some of the tensions in community‐driven development, which raises some important questions about the role of the State and external agencies in setting and enforcing equity criteria in community‐managed initiatives.  相似文献   

12.
National and local campaigns to encourage ‘Environmental Action’ use a range of media to increase the levels of activities such as recycling, energy saving and water conservation. These are conventionally focused on the population as a whole. The research reported in this paper suggests that such an approach, based on a belief that general campaigns are effective, might not be very effective and could be modified to take account of how different groups of people behave. In addition, the focus of campaigns on sectoral activities like water and energy saving might also be inappropriate given our findings, which are based on a survey of 1265 households in Devon. This found that three major types of behaviour characterise ‘Environmental Action’: purchasing, habitual activities and recycling behaviour. In addition, demographically and attitudinally defined clusters of individuals point to very different types of behaviour across the population. These findings suggest that more focused campaigns and a re-evaluation of how ‘Environmental Action’ is segmented would greatly assist policy makers in developing effective strategies for enhancing ‘Environmental Action’.  相似文献   

13.
The paper examines changing approaches to local economic development in the period since 1974. Initially, it proposes an ‘orthodox’ model of local economic development policies which emphasised the provision of a better industrial fabric, and of financial assistance to small, inner city firms. It suggests three recent directions of change in emphasis from this orthodox model: help in the creation of new entrepreneurs; replacement of public sector by private sector action; local authority shareholding in local firms by use of Enterprise Boards. Each approach makes different assumptions about the public/private sector relationship, the last two involve a more explicitly ideological stance on this issue.  相似文献   

14.
Phosphorus (P) is one of the most important mineral nutrients in agricultural systems, and along with nitrogen (N), is generally the most limiting nutrient for plant production. Farming systems have intensified greatly over time, and in recent years it has become apparent that the concomitant increase in losses of N and P from agricultural land is having a serious detrimental effect on water quality and the environment. The last two decades have seen a marked increase in research into the issues surrounding diffuse losses of P to surface and ground water. This paper reviews this research, examining the issue of P forms in runoff, and highlighting the exceptions to some generally held assumptions about land use and P transport. In particular the review focuses on P losses associated with recent P fertilizer application, as opposed to organic manures, both on the amounts and the forms of P in runoff water. The effects of the physicochemical characteristics of different forms of P fertilizer are explored, particularly in relation to water solubility. Various means of mitigating the risk of loss of P are discussed. It is argued that the influence of recent fertilizer applications is an under-researched area, yet may offer the most readily applicable opportunity to mitigate P losses by land users. This review highlights and discusses some options that have recently become available that may make a significant contribution to the task of sustainable management of nutrient losses from agriculture.  相似文献   

15.
The paper explores the relations of (1) regionalized climate change impulses; (2) their impacts on regional industry sectors; and (3) a regional econometric impact analysis. It develops a methodology by which the impulses of a regional climate change scenario can be transformed into ‘primary’ impacts on the capital stock and value added of climate-sensitive regional industries. These industries are vulnerable to ‘creeping’, i.e. continuous, climate change impulses, and they tend to react through ‘defensive’ investment. In addition, a singular flooding event is simulated for a specific local area and its different capital stocks. The stock damages and value-added losses of both the continuous industrial impacts and the singular flooding are inserted into a regional econometric model. This is sectorally disaggregated in stock, value-added and investment functions. It is also calibrated in the very-long run (through to the year 2040), according to different scenarios. The regional economic ‘secondary’ effects on the regional GNP are calculated. In addition to the calculation of regional economic primary and secondary impacts, the methodological issue of generating more transparency of the causal chains by use of damage functions, reaction functions, and comparative defensive strategies are discussed.  相似文献   

16.
Integration and integrated approaches are increasingly presented as new and superior ways to consider the environment in policy- and decision-making. If used in an uncritical way, this assertion could become a hindrance to good practice and could undermine efforts to defend or improve environmental quality. The aim of this paper is to provide the missing critical perspective through an investigation of the meanings of integration found in recent literature on assessment. This literature represents a broad survey of European (particularly UK) and US critiques of assessment practices, and proposals for better and usually ‘more integrated’ approaches. These critiques and proposals relate to a range of assessment contexts, from relatively technical issues of data handling, to questions of the design, choice and implementation of policy options. This paper also surveys, and contributes to, literature that questions the central goals and assumptions informing assessment practice and environmental governance more widely. Fourteen meanings of ‘integration’ are presented, with a discussion of the potential synergies and conflicts among them, and with environmental objectives. Integration is argued to be a matter of value judgements concerning assessment design in specific historical and social contexts. Far from providing a panacea, integration would appear to create as many challenges as it might resolve in seeking to achieve more sustainable development. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

17.
Nitrate in water removed from fields by subsurface drain ('tile') systems is often at concentrations exceeding the 10 mg N L(-1) maximum contaminant level (MCL) set by the USEPA for drinking water and has been implicated in contributing to the hypoxia problem within the northern Gulf of Mexico. Because previous research shows that N fertilizer management alone is not sufficient for reducing NO(3) concentrations in subsurface drainage below the MCL, additional approaches are needed. In this field study, we compared the NO(3) losses in tile drainage from a conventional drainage system (CN) consisting of a free-flowing pipe installed 1.2 m below the soil surface to losses in tile drainage from two alternative drainage designs. The alternative treatments were a deep tile (DT), where the tile drain was installed 0.6 m deeper than the conventional tile depth, but with the outlet maintained at 1.2 m, and a denitrification wall (DW), where trenches excavated parallel to the tile and filled with woodchips serve as additional carbon sources to increase denitrification. Four replicate 30.5- by 42.7-m field plots were installed for each treatment in 1999 and a corn-soybean rotation initiated in 2000. Over 5 yr (2001-2005) the tile flow from the DW treatment had annual average NO(3) concentrations significantly lower than the CN treatment (8.8 vs. 22.1 mg N L(-1)). This represented an annual reduction in NO(3) mass loss of 29 kg N ha(-1) or a 55% reduction in nitrate mass lost in tile drainage for the DW treatment. The DT treatment did not consistently lower NO(3) concentrations, nor reduce the annual NO(3) mass loss in drainage. The DT treatment did exhibit lower NO(3) concentrations in tile drainage than the CN treatment during late summer when tile flow rates were minimal. There was no difference in crop yields for any of the treatments. Thus, denitrification walls are able to substantially reduce NO(3) concentrations in tile drainage for at least 5 yr.  相似文献   

18.
Australia’s system of tropical rivers constitutes one of the largest and least changed drainage networks in the world. However increasing demand for water in parts of Australia, along with ongoing drought, is driving pressure to develop these rivers. This paper reports the results of a choice experiment (CE) to assess the benefits of different management strategies for three tropical rivers in northern Australia: the Daly, Mitchell and Fitzroy Rivers. The CE was carried out using a survey mailed to Australian urban populations. The results showed that 90% of Australians were willing to pay a once-off payment for the management of tropical rivers. Respondents who had visited or lived near the rivers were willing to pay more for cultural, recreational and environmental services than those who had not. Respondents classed as ‘developers’, who made up only 4% of the 684 respondents, considered a substantial income from irrigated agriculture as important. Unlike ‘environmentalists’ and ‘neutrals’, ‘developers’ were unwilling to pay for high quality recreational fishing or for having floodplains in good environmental condition. All groups, however, were willing to pay for high cultural values.  相似文献   

19.
There is growing awareness of the positive impact of reducing the amount of wasted food on greenhouse gas emissions, energy use, food and water security, and land use. In developed nations, food waste generated in homes is a large contributor to the total amount of food waste. The behaviours and practices associated with this waste prevention (and waste generation) are complex for a number of reasons: food waste is the result of multiple, interacting activities and this leads to separation between the activity and their consequences. These behaviours are usually performed for reasons unrelated to waste prevention and have both a marked habitual element and a pronounced emotional component. Furthermore, the prevention of food waste has less ‘visibility’ to other people (e.g. neighbours) than many other pro-environmental behaviours (e.g. recycling), and therefore social norms around ‘waste’ play a reduced role compared to more ‘visible’ activities.This paper discusses insights into these behaviours from research funded by the Waste & Resources Action Programme (WRAP) and its partners in the UK. It discusses how these insights have been used in the development of a successful public-engagement campaign, which has been influential in the recent reduction in household food waste. These insights are also discussed in light of commonly used behavioural models, highlighting that many of these models are not designed for multiple, complex behaviours. However, considering the subject of food waste through the ‘lenses’ of different academic disciplines has helped the development of the public engagement on this issue.  相似文献   

20.
An aspect of water resource development that has currently generated a good deal of interest among economists relates to the ‘economics of water transfer.’ Some recent investigations in this connection have studied the impact of transferring water from conventional uses (mainly agricultural) to newly emerging uses (e.g., pollution abatement, recreational, and industrial). The results of these studies indicate that water transfer contributes to economic growth, both directly and indirectly.  相似文献   

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