Optimisation of water procurement decisions in an irrigation district: the role of option contracts

Water supply instability is one of the main risks faced by irrigation districts and farmers. Water procurement decision optimisation is essential in order to increase supply reliability and reduce costs. Water markets, such as spot purchases or water supply option contracts, can make this decision process more flexible. We analyse the potential interest in an option contract for an irrigation district that has access to several water sources. We apply a stochastic recursive mathematical programming model to simulate the water procurement decisions of an irrigation district's board operating in a context of water supply uncertainty in south‐eastern Spain. We analyse what role different option contracts could play in securing its water supply. Results suggest that the irrigation district would be willing to accept the proposed option contract in most cases subject to realistic values of the option contract financial terms. Of nine different water sources, desalination and the option contract are the main substitutes, where the use of either depends on the contract parameters. The contract premium and optioned volume are the variables that have a greater impact on the irrigation district's decisions.     

Evaluation of drought management in irrigated areas

This paper focuses on the economic consequences of droughts for the irrigation sector. We develop a dynamic‐recursive mathematical programming farm model that assumes imperfect mobility of capital and labour as well as rational expectations about future water availability. The model is calibrated to 12 representative farms belonging to three irrigation communities of the Guadalquivir Basin (south Spain) and used to simulate the 1991–1997 period, which included 3 years of intense drought. Results indicate that the drought imposed significant costs on farmers, but show also that water managers partly exacerbated these costs by allocating excessive amounts of water to irrigators in the abundant years. The model is also used to evaluate the benefits of a perfect water supply forecast and to simulate the economic gains of a voluntary water banking scheme. Results show that the benefits resulting from the perfect forecast of water supply 1 year ahead would represent a relative gain of 5%. However, a voluntary banking system would allow farmers to increase their benefits by 32–82% depending on the supply system.     

The potential impact of markets for irrigation water in Italy and Spain: a comparison of two study areas*

The viability of irrigated systems in Southern Europe is closely linked to efficient institutional settings and water‐allocation mechanisms. A significant, although not widely used, mechanism for water allocation is an intra‐sectorial water market. The objective of this paper is to evaluate to what extent water markets may contribute to the improvement of the efficiency of water allocation and to the profitability of irrigated agriculture. The related issues of water allocation among farm types and farm specialisation are also addressed. The analysis is based on a basin‐level linear programming model, comparing the situation with and without a market. It includes both fixed and variable transaction costs and estimates their combined effects on market performances. The model is applied in two areas in Southern Italy and Spain, and simulates the behaviour of different farm types, derived from cluster analysis on a sample of farms in each area. The paper confirms that water markets could potentially improve the economic efficiency of water use, in terms of higher profit per hectare, given limited water availability. The potential improvements are associated with a more intense specialisation of farms and are strongly differentiated among farmers, particularly where significant restrictions to water availability occur. This corroborates the expectations of institutional difficulties in implementing water markets. However, the exchanges, and consequently the potential effects of water markets, are heavily affected by the actual level of water availability, as well as the size and the structure (fixed vs. proportional) of transaction costs. The paper calls for a more in‐depth analysis of the connections between market performances and institutional settings, as related to the issue of water‐agriculture policy design and coordination.     

Irrigation water pricing: differential impacts on irrigated farms

European water policy, as set out in the Water Framework Directive (WFD), requires all EU Member States to implement volumetric water pricing at rates that roughly cover the total costs of providing water services. The objective of this paper is to develop a methodology that, for the different types of farm in an irrigable area, will enable us to analyse the differential impact that a pricing policy for irrigation water would have. For this purpose, Multi-Attribute Utility Theory (MAUT) mathematical programming models were used. The methodology is implemented on a representative area in the Duero Valley in Spain. Our results show the usefulness of differential analysis in evaluating the impact of a water pricing policy. This allows significant differences in the evolution of agricultural incomes to be observed, as well as the recovery of costs by the State, demand for agricultural employment and the consumption of agrochemicals resulting from rising prices of irrigation water in various groups of farmers within a given irrigated area.     

The impact of water price uncertainty on the adoption of precision irrigation systems

We examine whether a firm is more or less likely to adopt precision technology when input prices are stochastic. The results are important to determining whether programs and contracts that reduce input price uncertainty may deter the adoption of conservation practices. An economic model of the technology adoption decision shows that the net effect of input price risk is ambiguous and depends on several factors including the shutdown effect, the mean price effect, the precision expansion effect, and the risk aversion effect. An empirical implementation of the model relies on data on water price and irrigation technology adoption observed in a California irrigation district over the period 1999–2002. The results show that a stable input price increases the adoption of precision technology, but the impact depends on crop choice and land quality characteristics.     

中国水权交易的发展及其试点推广效应

水权交易是目前解决水资源稀缺的一项重要政策工具,亦是中国当前水资源管理改革的重要方向之一。基于中国水权交易所2016—2022年的交易数据对中国水权交易的总体概况、不同交易类型的水权交易特征进行统计描述性分析,并讨论其试点推广效应。研究表明:目前中国的水权交易以取水权交易为主,其次为区域水权交易,灌溉用水户水权交易渐趋活跃;区域水权交易主要表现为用水总量指标在区域间的重新配置,取水权交易主要表现为行业间的取水权交易,而灌溉用水户水权交易主要表现为行业内的水权交易;政府在水权交易中发挥了重要作用,随着水权交易的发展,参与主体开始出现多元化,更多的用水户开始进入水市场;中国的水权交易试点具有一定的推广效应,不仅仅表现为“量”的增多,还表现在交易方式上的创新。中国水权交易未来的发展空间在于不断创新水权交易方式并激励更多的用水户参与水权交易,需要因地制宜推进水权改革,加快推动初始水权的分配与确权工作;同时,还需要进一步完善水资源计量与监控体系,并积极推动水权交易法规制度建设,进一步推进水权交易市场的发展。     

Elicitation of irrigators' risk preferences from observed behaviour

Water trading in the Murray–Darling Basin of Australia has developed to the point where it is a common adaptation tool used by irrigators, making it an apt case study to elicit the marginal value of irrigation water and irrigators' risk preferences in two key industries with differing levels of water dependence. Our data come from large‐scale and representative surveys of irrigated broadacre and horticultural farms in the Murray–Darling Basin over a 6‐year period. The marginal contribution of irrigation water to profit is estimated at $547 and $61/ML on average in horticulture and broadacre, respectively. Horticultural irrigators are found to be averse to the risk of large losses (downside risk) while broadacre irrigators are averse to the variability (variance) of profit.     

Coping with drought with innovative pricing systems: the case of two irrigation water management companies in France

In recent years, France has been facing particularly severe drought periods especially in summer. In a country where agriculture is the largest water user, some irrigation management companies have implemented innovative pricing systems to handle this situation. The objective of this article is to analyze the impact of these new management systems on farmers’ incomes, the revenue of the management companies, and the amount of water used. To do that, we develop a methodology using a stochastic model that simulates the representative farmer's optimal behavior in a context of climatic variability. An empirical application is made with a crop growth model and data collected from the Midi‐Pyrenees region. The results show that using these specific nonlinear pricing systems allow irrigation water managers to reduce the impact of drought on production. Moreover, the type of pricing implemented depends on the characteristics and capabilities of the water company. More particularly, these pricing systems can be used to anticipate agricultural water demand in order to avoid imbalance with water availability.     

Forty years of irrigation development and reform in China

This study reviews 40 years of irrigation development in China including the transformation of the institutional and incentive structures in irrigation management. After rural reforms in the 1970s, irrigation investments slowed until the late 1990s. In North China, farmers became major investors in groundwater irrigation, leading to property rights’ transfer of tube wells from collective to private ownership. Despite positive effects in cropping patterns, farmer income and development of groundwater markets, privatisation has accelerated groundwater table deterioration. Since the middle of 1990s, Water User Associations have replaced village collective management of surface irrigation. This approach was adopted by most provinces by early 2001 with mixed results; only institutions with water‐saving incentives realised efficient irrigation. The Government is reforming water price policies to provide water‐saving incentives to farmers while not hurting their income. While China has focused on water rights and markets, and despite regulations and pilot projects, full implementation of water rights has been slow. Research reveals greater policy scope for expanding irrigation technologies that generate real water saving to rural areas. Given pressure associated with water scarcity and concern for food security, further effective reforms in irrigation and policy incentives are expected. The Government has also initiated some pilot projects to resolve increasing water scarcity problems through adjusting agricultural production activities.     

Irrigation technology adoption and its implication for water conservation in the Texas High Plains: a real options approach

Water shortage has been a significant issue for several decades in the Texas High Plains. Agriculture has been identified as the main activity contributing to this shortage. To address this issue, many efforts have been focused on the possible adoption of sophisticated irrigation systems with high levels of water application efficiency. In this study, the entry and exit thresholds for the low‐energy precision application (LEPA) system are analyzed simultaneously in cotton farming in the Texas High Plains using a real options approach. The results show that the LEPA system is profitable only when cotton price is set above $1.59/kg. The exit (entry) threshold is consistently low (high) over a range of values for parameter changes including investment cost, exit cost, variable cost, risk‐adjusted discount rate, and volatility rate, so it is unlikely that farmers with irrigation systems in place would leave them easily. This implies that to attain the goal of saving water, Lubbock County needs to focus on convincing current farmers to replace old irrigation systems with new ones.     

Water pricing policies,public decision making and farmers' response: implications for water policy

The problems caused by water scarcity demand important changes in the criteria and objectives of water policies. The agricultural sector in Spain consumes up to 80% of all available hydric resources and the need to increase the efficiency of current uses of water in the agricultural sector is at the core of the country's national water policy. One alternative would be to resort to water pricing policies with the aim of providing incentives to save water consumption although it would inflict a certain degree of income losses to the farmers and raise the revenue collected by the water authorities. The objective of this research is to analyze the effect caused by the application of different water pricing policies on water demand, farmers' income and the revenue collected by the government agency. To undertake this analysis a dynamic mathematical programming model has been built that simulates farmers' behavior and their response to different water pricing scenarios. Empirical application of the model has been carried out in several irrigation districts in Spain covering varied farm regions and river basins. Results show that the effects of alternative pricing policies for irrigation water are strongly dependent on regional, structural and institutional conditions and that changing policies produce distinct consequences within the same region and water district. Thus, equivalent water charges would create widespread effects on water savings, farm income and collected government revenue across regions and districts.     

Adoption of farm‐based irrigation water‐saving techniques in the Guanzhong Plain,China

This article analyses adoption of farm‐based irrigation water saving techniques, based on a cross‐sectional data set of 357 farmers in the Guanzhong Plain, China. Approximately 83% of the farmers use at least one farm‐based water‐saving technique. However, the traditional, inefficient techniques border and furrow irrigation are still prevalent whereas the use of advanced, more efficient techniques is still rather rare. We develop and estimate an adoption model consisting of two stages: awareness of water scarcity and intensity of adoption. We find that awareness of water scarcity and financial status enhance adoption of more advanced techniques whereas access to better community‐based irrigation infrastructure discourages it. We furthermore find both community‐based irrigation infrastructure and farm‐based irrigation water‐saving techniques have mitigating effects on production risk. From the results it follows that adoption can be stimulated via financial support and via extension aimed at enhancing awareness of water scarcity.     

Water policy reform in Australia: lessons from the Victorian seasonal water market*

The nature of the seasonal water market is examined using a theoretical model and empirical evidence from the Victorian market. Drivers of the seasonal opportunity cost of water include the underlying nature of investment in the industry made in the context of risky entitlement yields; and the timing and nature of information regarding seasonal water availability and rainfall. Seasonal water markets facilitate the re‐allocation of water availability according to this short‐run opportunity cost. Evidence from the market suggests that transactions costs are low and most of the existing constraints to trade in seasonal allocations are the result of hydrological conditions. Analysis of market data suggests that the price response of the market to water availability is much more pronounced in years of low rainfall. The implications of the paper for wider policy reform are that attention should be paid to improving property rights for the management of intertemporal risk before other reforms, such as broadening of permanent water markets and institutionalising environmental flows, are implemented. This is because these other reforms will change the spatial and temporal pattern of water use and thus affect reliability, which underpins the value of water in irrigated agriculture.     

Impacts of changing water inflow distributions on irrigation and farm income along the Drâa River in Morocco

Irrigation water is essential for agriculture in the arid Drâa River basin in Morocco but climate change leads to increasingly unreliable water supply in the area. This article analyzes impacts of changing water inflow distributions on irrigation and farm income extending a conjunctive river basin model toward a stochastic modeling approach. Regional climate scenarios are used to derive a maximum likelihood density estimate of current and future water supplies. Based on these distributions, Monte Carlo simulations are performed to obtain stochastic model results on surface and groundwater irrigation as well as economic indicators for six oases along the river. The probability of farmers to receive revenues below the subsistence level is around 2% under current conditions, but this is likely to rise to rates of 6% to 15% depending on the underlying climate change scenario. The composition of water sources for irrigation will shift to more groundwater use. The river basin model is able to represent complex spatial interactions between oases as well as a partial complementarity between groundwater and surface water irrigation due to salinity management effects. Interestingly, the value of groundwater is not necessarily increasing under future climatic conditions as salinity problems are aggravated with expanded groundwater use.     

Irrigation water productivity in Cambodian rice systems

Knowledge of the marginal productivity of water is crucial for decisions about its allocation between uses, which is particularly important in the context of increasing competition for water. Using primary, plot‐level panel data, this article estimates the marginal productivity of water from supplementary irrigation in lowland rice systems in Cambodia, taking into account farmer and plot heterogeneity as well as self‐selection of supplementary irrigation. Our estimates indicate a range of elasticities for rice output with respect to water inputs of between 0.057 and 0.069 for wet season production, substantially lower than previous estimates based on either aggregate or trial data. We discuss the policy implications of these results, in particular with respect to the utility of demand management policies and the challenges they pose to the decentralization of water management to Farmer Water Users Groups.     

Property rights and western United States water markets*

This paper addresses water scarcity issues in the American West and examines the allocation of water through the appropriative rights system and the extent markets are used to reallocate water from low‐ to high‐valued uses. The unique physical properties of water make it difficult to bound and measure, which makes defining property rights difficult. Markets are also impeded by disputes over third‐party effects due to the interdependencies of water users and complex institutional arrangements that dilute decision‐making authority. Analysis of water trading in the western United States indicates that the rate of permanent transfers is increasing over time and urban users are paying higher prices relative to agricultural users.     

Modelling hydroclimatic uncertainty and short‐run irrigator decision making: the Goulburn system*

Australia has an incredibly variable and unpredictable hydroclimate, and while irrigation is designed to reduce risk, significant uncertainty remains in both seasonal water availability (‘allocations’) and irrigation crop water requirements. This paper explores the nature and impacts of seasonal hydroclimatic uncertainty on irrigator decision making and temporary water markets in the Goulburn system in northern Victoria. Irrigation and water trading plans are modelled for the three seasons of the irrigation year (spring, summer and autumn) via discrete stochastic programming, and contrasted against a perfect information base case. In water‐scarce environments, hydroclimatic uncertainty is found to be costly, in terms of both the efficiency of irrigation decisions and the allocation of water via the water market.     

Macro–micro feedback links of water management in South Africa: CGE analyses of selected policy regimes

The pressure on an already stressed water situation in South Africa is predicted to increase significantly under climate change, plans for large industrial expansion, ongoing rapid urbanization, and government programs to provide access to water to millions of previously excluded populations. This article employs a general equilibrium approach to examine the economy‐wide impacts of selected macro and water‐related policy reforms on water use and allocation, rural livelihoods, and economy at large. The analyses reveal that implicit crop‐level water quotas reduce the amount of irrigated land allocated to higher‐value horticultural crops and create higher shadow rents for production of lower‐value water‐intensive field crops, such as sugarcane and fodder. Accordingly, liberalizing local water allocation within irrigation agriculture is found to work in favor of higher‐value crops, and expand agricultural production and exports and farm employment. Allowing for water trade between irrigation and nonagricultural uses fuelled by higher competition for water from urbanization leads to greater water shadow prices for irrigation water with reduced income and employment benefits to rural households and higher gains for nonagricultural households. The analyses show difficult trade‐offs between general economic gains and higher water prices, which place serious questions on subsidizing water supply to irrigated agriculture, i.e., making irrigation subsidies much harder to justify.     

A general equilibrium analysis of conjunctive ground and surface water use with an application to Morocco

Groundwater resources (GW) account for nearly 30% of the world's sustainable water supplies. Yet, this resource, which is fraught with externalities, has largely been left unregulated. The economic literature on GW is predominantly of a partial equilibrium type. We analyze GW regulation in a general equilibrium setting, focusing on the stabilization value of GW under natural (drought) and economic (rural–urban water transfer) shocks. A general equilibrium approach allows evaluating direct and indirect effects of GW regulation on agriculture and nonagriculture sectors and extends the scope for water policy. The analysis is applied to Morocco by extending an existing computable general equilibrium (CGE) model to include ground and surface water (SW) resources. We study effects of (i) an increase in GW extraction cost (e.g., as a result of prolonged extraction beyond natural recharge that lowers the aquifer's water table), (ii) a transfer of SW from rural (irrigation) to urban (domestic) use, and (iii) a reduction of water availability due to severe drought. We estimate the value of GW and assess the direct (partial equilibrium) and indirect (general equilibrium) impacts. We find that GW plays a critical role in mitigating the negative effects of these types of shocks.     

The linkage between the U.S. ethanol market and developing countries’ maize prices: a panel SVAR analysis

The major expansion of U.S. ethanol production raises concerns about the potential detrimental impacts on developing countries’ agricultural prices, farm income, and food security. To assess the sensitivity of maize prices to ethanol production, this study explores the linkage between the U.S. ethanol market and developing countries’ maize prices. The econometric approach, based on a panel structural vector autoregression model, captures market interdependencies and the likelihood that developing countries’ responses are both heterogeneous and dynamic. The results indicate that the U.S. ethanol market's impacts on maize prices in developing countries are heterogeneous and that coastal countries are more susceptible to U.S. economic shocks. The estimates also suggest that countries more dependent on food imports and/or receiving U.S. food aid are at a higher risk of being affected by such shocks. Overall, the results indicate that those countries with the greatest sensitivity and exposure to global agricultural commodity markets could benefit from domestic policies and international assistance, which reduce their exposure to impacts from the U.S. maize market.