Estimating economic value of agricultural water under changing conditions and the effects of spatial aggregation

Given the high proportion of water used for agriculture in certain regions, the economic value of agricultural water can be an important tool for water management and policy development. This value is quantified using economic demand curves for irrigation water. Such demand functions show the incremental contribution of water to agricultural production. Water demand curves are estimated using econometric or optimisation techniques. Calibrated agricultural optimisation models allow the derivation of demand curves using smaller datasets than econometric models. This paper introduces these subject areas then explores the effect of spatial aggregation (upscaling) on the valuation of water for irrigated agriculture. A case study from the Rio Grande-Rio Bravo Basin in North Mexico investigates differences in valuation at farm and regional aggregated levels under four scenarios: technological change, warm-dry climate change, changes in agricultural commodity prices, and water costs for agriculture. The scenarios consider changes due to external shocks or new policies. Positive mathematical programming (PMP), a calibrated optimisation method, is the deductive valuation method used. An exponential cost function is compared to the quadratic cost functions typically used in PMP. Results indicate that the economic value of water at the farm level and the regionally aggregated level are similar, but that the variability and distributional effects of each scenario are affected by aggregation. Moderately aggregated agricultural production models are effective at capturing average-farm adaptation to policy changes and external shocks. Farm-level models best reveal the distribution of scenario impacts.     

Why an urban population continues to grow under intensifying water scarcity: an answer from generalized water resources

ABSTRACT

Previous studies indicated that the population size would arrive at its upper limits under the intense water scarcity in Urumqi. However, these ‘limits’ have been repeatedly exceeded, and the population has grown from one million in the 1980s to four million in 2014. This phenomenon is viewed as a ‘mystery of the population carrying capacity of water resources’. This paper investigates the mystery under an amplified framework of generalized water. The entropy of virtual water was 48.9, and 3.08 billion m³ of external virtual water flowed into Urumqi. External virtual water makes a main contribution to increase water supplies under acute water scarcity, and this contribution results from the characteristic of dissipative structure in an urban economy. It is proved that generalized water is one of the most essential answers to the mystery at least. Generalized water plays an important role and generalized water management is necessary in an urban economy.     

May land use change reduce the water deficiency problem caused by reduced brown coal mining in the state of Brandenburg?

Surface mining alters the water regime not only locally, but also regionally. The reduced brown coal mining in the south-east of the state Brandenburg (Germany) leads to decreasing river discharge and consequently to a shortage in the water supply. Land use change is one possible option to counteract this development. In this simulation study, we explored the impact of temporary and permanent set-aside of arable land on Brandenburg’s regional water balance. Temporary and permanent set-aside were considered as major measures towards deintensification of agriculture. Simulations were performed using the regional ecohydrological model SWIM, which integrates hydrological processes, vegetation growth, erosion and nutrient dynamics. The model was used to simulate the consequences of different land use change scenarios on main components of the regional water balance. Changes in the use of arable land altered clearly its water balance. The impact of these changes on the regional water balance for Brandenburg did not exceed ±10% for its single components. Opposite tendencies were established in the simulations by contrasting effects of temporary and permanent set-aside of arable cropland. While temporary set-aside increased runoff from the whole area up to 6.7% due to lower evapotranspiration and higher soil moisture in arable land, the conversion of agricultural land within river corridors to meadows had an opposite effect on regional runoff (6.9% decrease) due to higher water retention coefficients and higher evapotranspiration losses. Therefore, only temporary set-aside may compensate to some extent for the anticipated decrease in river discharge.     

Improved hydrological projections and reservoir management in the Upper Indus Basin under the changing climate

The availability of water resources plays an important role for the economy of a country. The nexus of energy‐food‐water are interlinked and of particular importance in the uncertain environment of developing countries. In Pakistan, agriculture contributes 25% to the gross domestic product. The Indus River contributes 44% of the available water to irrigation of crops and the ecosystem, and currently produces 5,112 MW electricity, with the potential to produce 38,602 MW electricity. This makes it important to investigate the status of water availability in the Upper Indus Basin under existing emission scenarios. In this study, the future availability of water is projected for the Indus River under the A2, B2, RCP4.5 and RCP8.5 emission scenarios. A meta‐analysis has been conducted to present a combined picture by combining the results from the emission scenarios. Our meta‐analysis shows higher confidence in RCPs projections. The results show that suffcient water will be available in the Indus River that will meet the demands of water in future but there will be scarcity of water in some months under each scenario. However, by proper management and optimum utilisation of the available water, this scarcity can be resolved.     

浅谈建筑给排水中的节水技术

主要结合当前水资源缺乏的严峻形势,立足建筑给排水,从热水循环方式的选择、中水处理、推广新型节水设备等方面提出一些给排水设计的想法和建议,从而缓解城市用水供需矛盾,减少水资源的隐形浪费。     

Tariffs, factor prices, and welfare in a spatial oligopoly

In this paper we derive endogenous tariff rates for a tariff revenue maximizing policy and a welfare maximizing policy (optimal tariff) in a spatial framework. The underlying model is that of a spatial oligopolistic market with domestic and foreign firms. We assess the outcomes of the model for different tariff rates and the free trade situation, the stress being on welfare considerations. Compared to the traditional theory of international trade and tariffs, this approach affords useful insights into the role of firms‘ locations and transportation costs for profits and consumers‘ surplus in the case of alternative trade policies. Received: February 1996 / Accepted in revised form: April 1997     

基于“绿色机场”理念的某机场给排水设计要点

建设绿色机场,实现机场绿色低碳运行,已成为全球机场发展的共同选择。开展绿色机场建设的研究与实践已成为我国民航面临的一项重要任务,打造绿色机场也是一项庞大而长期的工程。哈尔滨太平国际机场扩建工程作为黑龙江省重点项目,在给排水工程绿色设计中进行了诸多有益的探索。本文从绿色设计、节水、污水处理与中水综合利用等方面探讨了给排水专业在哈尔滨太平国际机场扩建工程中践行"绿色机场"设计理念的方法及要点。     

Scarcity and Abundance: Urban Agriculture in Cuba and the US

In urban agriculture, there is a direct connection between scarcity and abundance: with the threat of food shortages so often acting as an effective trigger for food-growing enterprises. Produce can also be grown with few or limited resources. André Viljoen and Katrin Bohn of Bohn&Viljoen Architects juxtapose the experience of the organopónicos, or market gardens, in Cuba, which have proliferated since the US trade blockade of the 1990s and ensuing fuel shortages, and more recent experiments in food production in North American cities that are learning from their example.     

Risk‐based water resources planning in practice: a blueprint for the water industry in England

Resilient water supplies in England need to be secured in the face of challenges of population growth, climate change and environmental sustainability. We propose a blueprint for water resources planning that uses system simulation modelling to estimate the frequency, duration and severity of water shortages at present and in the context of future plans and scenarios. We use multiobjective optimisation tools to explore trade‐offs between these risk metrics and cost of alternative plans, and we use sensitivity analysis to identify plans that robustly achieve targets for tolerable risk, alongside other performance objectives. The results of a case study in the Thames basin demonstrate that the proposed methodology is feasible given commonly available data sets and models. The proposed method provides evidence with which to develop water resource management plans that demonstrably balance the risks of water shortages, costs to water users and environmental constraints in an uncertain future.     

Artificial shortage of surface water: how can water demand management mitigate the scarcity problem?

Water demand management stresses the crucial roles of water user motivations in balancing actual water availability and competing human needs. This paper shows how the absence of such motivations influences artificial water scarcity, even in resource‐abundant countries, and how slight modifications to economic instruments (surface water charges in particular) might solve the problem. Data from the Czech Republic are used to illustrate the rationale behind the artificial scarcity problem and its solution. A model with feedback based on historical surface water abstraction data is built to simulate the impacts of different payment modification scenarios.     

Unravelling Chinese industrial structure optimization paths within Regional Comprehensive Economic Partnership considering the virtual trade of water and water pollutants

Massive commodity transactions lead to enormous virtual water and water pollution transfer; this phenomenon will be intensified within the process of Regional Comprehensive Economic Partnership (RCEP) enforcement. This study applied multi-regional input–output and scenario simulation approach to reveal the virtual water elements flow, while exploring the trade structure optimisation roadmap for China. Results unveiled that China was a virtual water net exporter (9.17 billion tons), also the largest importer of water pollutants (N 622456 tons and P 136110 tons) among RCEP countries in 2015. In order to alleviate the water pressure in China, the textiles and other manufacturing industries should be limited, while the service industry is encouraged. Optimal scenario can realize 29.8% water conservation and 8% water pollutants reduction and also achieve a 36.5 million dollars trade volume increase. This research improves trade-off balance between water environment and economy at multi-regional level and accelerates green trade in economic partnerships globally.     

Using contingent valuation and choice experiment to value the impacts of agri-environmental practices on landscapes aesthetics

This study explores the willingness to pay (WTP) for an improvement of the environmental situation in agricultural areas with a specific focus on landscape aesthetics. We used the contingent valuation method to measure the discrete value of landscape aesthetics externalities produced by different beneficial management practices implementation scenarios. The choice experiment method was also used to measure the economic value of other ecosystem services in order to situate landscape in consumers’ preferences among other non-market benefits produced by agri-environmental practices. We found important WTP for landscape aesthetics improvement, as well as for other ecosystem services, such as water quality and fish diversity.     

Wastewater reuse potential analysis: implications for China's water resources management

It has been recognized that wastewater reuse or reclamation serves as an efficient and valuable way to cope with the scarcity of water resources and severity of water pollution. This paper presents the systematic framework of wastewater reuse potential estimation. Based on the regional disparities in China, a linear programming optimization model is developed to explore the potential wastewater reuse quantities, under physical and economic constraints. Sensitivity analysis and Robust Counterpart (RC) optimization are performed to discuss the influences of key parameters and the reuse quantity's decision making under uncertainty. Based on the model, effectiveness of different policy scenarios of water price changes are simulated and evaluated, providing information regarding China's water and wastewater management.     

Projected water consumption in future global agriculture: scenarios and related impacts

Global stress on water and land resources is increasing as a consequence of population growth and higher caloric food demand. Many terrestrial ecosystems have already massively been degraded for providing agricultural land, and water scarcity related to irrigation has damaged water dependent ecosystems. Coping with the food and biomass demand of an increased population, while minimizing the impacts of crop production, is therefore a massive upcoming challenge. In this context, we developed four strategies to deliver the biotic output for feeding mankind in 2050. Expansion on suitable and intensification of existing areas are compared to assess associated environmental impacts, including irrigation demand, water stress under climate change, and the productivity of the occupied land. Based on the agricultural production pattern and impacts of the strategies we identified the trade-offs between land and water use. Intensification in regions currently under deficit irrigation can increase agricultural output by up to 30%. However, intensified crop production causes enormous water stress in many locations and might not be a viable solution. Furthermore, intensification alone will not be able to meet future food demand: additionally, a reduction of waste by 50% along the food supply chain or expansion of agricultural land is required for satisfying current per-capita meat and bioenergy consumption. Suitable areas for such expansion are mainly located in Africa, followed by South America. The increased land stress is of smaller concern than the water stress modeled for the intensification case. Therefore, a combination of waste reduction with expansion on suitable pastures generally results as the best option, along with some intensification on selected areas. Our results suggested that minimizing environmental impacts requires fundamental changes in agricultural systems and international cooperation, by producing crops where it is most environmentally efficient and not where it is closest to demand or cheapest.     

Climate impacts on European agriculture and water management in the context of adaptation and mitigation—The importance of an integrated approach

We review and qualitatively assess the importance of interactions and feedbacks in assessing climate change impacts on water and agriculture in Europe. We focus particularly on the impact of future hydrological changes on agricultural greenhouse gas (GHG) mitigation and adaptation options. Future projected trends in European agriculture include northward movement of crop suitability zones and increasing crop productivity in Northern Europe, but declining productivity and suitability in Southern Europe. This may be accompanied by a widening of water resource differences between the North and South, and an increase in extreme rainfall events and droughts. Changes in future hydrology and water management practices will influence agricultural adaptation measures and alter the effectiveness of agricultural mitigation strategies. These interactions are often highly complex and influenced by a number of factors which are themselves influenced by climate. Mainly positive impacts may be anticipated for Northern Europe, where agricultural adaptation may be shaped by reduced vulnerability of production, increased water supply and reduced water demand. However, increasing flood hazards may present challenges for agriculture, and summer irrigation shortages may result from earlier spring runoff peaks in some regions. Conversely, the need for effective adaptation will be greatest in Southern Europe as a result of increased production vulnerability, reduced water supply and increased demands for irrigation. Increasing flood and drought risks will further contribute to the need for robust management practices.The impacts of future hydrological changes on agricultural mitigation in Europe will depend on the balance between changes in productivity and rates of decomposition and GHG emission, both of which depend on climatic, land and management factors. Small increases in European soil organic carbon (SOC) stocks per unit land area are anticipated considering changes in climate, management and land use, although an overall reduction in the total stock may result from a smaller agricultural land area. Adaptation in the water sector could potentially provide additional benefits to agricultural production such as reduced flood risk and increased drought resilience.The two main sources of uncertainty in climate impacts on European agriculture and water management are projections of future climate and their resulting impacts on water and agriculture. Since changes in climate, agricultural ecosystems and hydrometeorology depend on complex interactions between the atmosphere, biosphere and hydrological cycle there is a need for more integrated approaches to climate impacts assessments. Methods for assessing options which “moderate” the impact of agriculture in the wider sense will also need to consider cross-sectoral impacts and socio-economic aspects.     

The Role of Groundwater as a Strategic and Economic Asset in Northern Ireland

In Northern Ireland, groundwater contributes 77 Ml/d out of 700 Ml/d in public supply, and a further 31 Ml/d to private users. Of the latter, agriculture takes about 11 Ml/d and industry uses 18 Ml/d; a further 2 Ml/d are consumed by up to 15 000 people for rural domestic needs. Groundwater is a protected asset and, as such, its use should be maximized for both strategic and commercial gain. Increased demand on the public supply system by the year 2001 will involve no new major groundwater input, but private exploitation of groundwater will increase, particularly by the specialist industries such as electronics and water bottling.     

Modeling the effects of population growth on water resources: a CGE analysis of the South Platte River Basin in Colorado

This research examines the general equilibrium implications of economic and population growth on a fixed (or exogenously determined) total supply of available water in the South Platte River Basin in Colorado. Instead of looking at the effects of increased demand for water on a fixed allocation regime, we allow for transfers of water between agricultural and municipal water users based on the respective factor demand for water across the economy. The study utilizes an 18-sector computable general equilibrium (CGE) model, where water is incorporated as a primary factor of production for agricultural operations and for a municipal water supply sector, but as an intermediate input for all other sectors. It is determined that, by allowing for water transfers with a fixed supply of water, the projected 50% increase in population from 2002 to 2030 will result in a 5.7% shift in water allocation from agriculture to other sectors. However, the total real value of agricultural sales is expected to increase slightly over this same period. The price of municipal water is expected to increase by 8.4% and the price of agricultural water is expected to increase by 10.4%. This result is contrasted to a scenario where significant barriers to water transfers are enacted. In this case the price of municipal water increases by 25% and agricultural water prices remain constant.     

Water scarcity: Can virtual water operators help?

The changing climate is likely to have an effect on water and sewerage sectors. To deal with this challenge regulators need consider ways to better signal the value of water, that is, such that water is more expensive where it is scarce. This paper shows that virtual water operators (VWO) could result in entrants internalising this value and provide regulators with an estimate of it. With water scarcity, entrants will face higher cost of entry as they will need to acquire expensive, if available, abstraction licences. Given these higher prices they will also be willing to pay higher prices to become a VWO in those areas with scarcity. This means that VWOs can help to reveal the real value of water. Further, by introducing these considerations into part of the incumbent’s capacity, VWO also help to introduce this cost into the supply of the incumbent.     

The potential of wastewater heat and exergy: Decentralized high-temperature recovery with a heat pump

There is a large potential in the heat losses from the wastewater leaving a building. We present a novel concept for recovering this heat. Instead of recovering it in a mixed state, the recovery immediately after use is evaluated. This allows the exploitation of the higher temperatures found at the points of warm water usage. By integrating a heat pump to utilize this heat, we can produce a higher temperature heat supply while maintaining a low temperature-lift requirement. This leads to the possibility of directly regenerating the hot water supply through wastewater heat recovery. The concept is a result of research into low exergy building systems, and is part of the IEA ECBCS Annex 49. We have modeled the annual performance of two different system scenarios, which result in a potential average annual coefficient of performance (COP) of over 6. The first scenario supplies up to 4400 kWh of heat for all hot water events with only 790 kWh of electricity, while the second scenario regenerated directly the hot water supply just for bathroom fixtures at 2400 kWh with just 410 kWh of energy. This is a significant reduction in the demand for hot water supply of a building compared to most modern installations.     

上海西郊国际农产品交易中心的设计

上海西郊国际农产品交易中心是我国目前建设规模最大、设施最先进的农产品物流交易区,在借鉴国内外同类专业市场的经验后,设计秉持"流畅性、安全性、可变性"原则,采用流畅的交通组织、合理的交易流程和弹性的设计等,旨在创建一个安全、高效、可持续发展的公共物流交易场所。