Risk aversion in agricultural water management investments in Northern Ghana: experimental evidence

Sub‐Saharan Africa (SSA) is one of the regions in the world most affected by food price volatility and production variability. Poor small‐scale farmers in this region are particularly vulnerable to this variability. As a result, households may be reluctant to adopt new agricultural water management (AWM) technologies when they involve more risk than what they mitigate. Despite risk's role in AWM investments, there have been few attempts to estimate the magnitude and nature of risk aversion in relation to this type of farm decisions. To partially close this gap, this article uses an experimental approach applied to 137 households in Northern Ghana. We find that more than 70% of households are moderately or slightly risk averse. This contrasts with other studies in SSA, where most household decision‐makers exhibit severe to extreme risk aversion. We also find that households that stand to lose as well as gain something from participation in games are less risk averse than households playing gains‐only games. This result suggests that most farmers’ current wealth put them at risk of falling into a poverty trap. Thus, the losses from the riskiest investments on AWM technologies may fall more heavily on the poor, suggesting that additional efforts be given to the creation of viable insurance mechanisms.     

Spot water markets and risk in water supply

Water availability patterns in semiarid regions are typically extremely variable. Even in basins with a highly developed infrastructure, users are subject to unreliable water supplies, incurring substantial economic losses during periods of scarcity. More flexible instruments, such as voluntary exchanges of water among users, can help users to reduce risk exposure. This article looks at the effects of spot water markets on the economic risk caused by water availability variations. Our theoretical and empirical risk analyses are based on the random profits of water users. Profit probability density functions are formally and graphically characterized for both water sellers and buyers under several possible market outcomes. We conclude from this analysis that, where water supply is stochastic, water markets unambiguously reduce both parties' risk exposure. The empirical study is conducted on an irrigation district in the Guadalquivir Valley (Southern Spain), where there is a high probability of periods of extreme water scarcity. Water demand functions for the district representative irrigators and a spatial equilibrium model are used to simulate market exchanges and equilibrium. This programming model is combined with statistical simulation techniques. We show that the profit probability distribution of a representative irrigator is modified if water exchanges are authorized, leading to risk reductions. Results also indicate that if the market were extended to several districts and users that are subject to varying hydrological risk exposure, extremely low‐profit events would be less likely to occur. In sum, we show that exchanging water in annual spot markets can reduce farmers' economic vulnerability caused by water supply variability across irrigation seasons. These results support the water policy reform carried out in Spain in 1999 to allow for voluntary water exchanges among right holders.     

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.     

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.     

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.     

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.     

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.     

Using proportional modeling to evaluate irrigator preferences for market‐based water reallocation

Irrigators’ policy preferences for water reallocation programs usually take the form of proportional data, where one option will be relatively more or less favored than another in the composition of a government's total budget apportionment to address water reform. This study applies a zero‐one inflated beta regression to model Murray–Darling Basin irrigators’ preferences for market‐based water policy programs. Market‐based arrangements are more likely to provide efficient solutions to water reallocation problems, particularly where future uncertainty and appropriate pricing induce irrigator preferences for such programs. Our modeling of drivers of irrigator preferences for government expenditure on market‐based programs identified different determinants of zero (a corner solution) and proportional outcomes for the reallocation of Murray–Darling Basin water. In addition, the proportional modeling identifies some variables (namely, state regional influences, the type of farm production and recent debt, low income, or water allocation stressors) that increase engagement with market‐based programs. Interestingly, while price variables are important and statistically significant, they appear to be less relevant to program engagement than other influences.     

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.     

The impact of water conservation and intensification technologies: empirical evidence for rice farmers in Ghana

This study employs the propensity score matching model to examine the impact of the adoption of water conservation and intensification technologies on farm output and income among small-scale lowland rice farmers in the Northern Region of Ghana. The matching was conducted based on the Mahalanobis distance combined with the propensity score. Balancing tests by checking the mean standardized absolute bias in the matched sample were conducted as well as a sensitivity analysis was conducted to check for hidden bias due to unobservable selection. The empirical results show a positive and significant impact of the adoption of bunds technology on input demand as well as a positive but insignificant impact on output supply and net returns. Adopters of the dibbling technology were found to have higher output supply, whereas no statistically significant difference was found between the incomes of adopters and nonadopters of dibbling seed method. The results, however, reveal a positive and significant effect on output and net returns when the dibbling method is combined with intensified weeding. The estimates were found to be relatively insensitive to hidden bias.     

Incentives to managers or participation of farmers in China's irrigation systems: which matters most for water savings,farmer income,and poverty?

The overall goal of our article is to better understand which matters for water savings, farmer income and poverty in China's irrigation systems: incentives to managers or participation of farmers. To pursue this goal, the article has three objectives. First, we track the evolution of water management reform, examining the practice of providing incentives to managers, and increasing the participation of farmers. Second, we identify the impact of water management reform on crop water use. Specifically, we want to measure whether or not incentives to managers and farmer participation in water management institutions affect the performance of the irrigation system. Because we also are interested in the potential results of water management reform, the article explores how changes in incentives and farmer participation affect farmer income and poverty. Based on a random sample of 51 villages and 189 farmers in four large irrigation districts in Ningxia and Henan provinces, both in China's Yellow River Basin, our results show that the two major forms of water management reform, water users' associations (WUAs) and contracting, have begun to systematically replace traditional forms of collective management. Our analysis demonstrates, however, that it is not the nominal implementation of the reform that matters, but rather it is the creation of new management institutions that offer water managers monetary incentives that lead to water savings. In contrast to the original design of China's reform policies, participation of farmers has not played a role in saving water. Importantly, given China's concerns about national food production and poverty alleviation, the reductions in water, at least in our sample sites, do not lead to reductions in income and do not increase the incidence of poverty.     

Integrated assessment of water framework directive nitrate reduction measures

This article illustrates a statistical approach for deriving farm economic impacts of policy options aiming to reduce nitrate diffuse pollution. Building upon Fezzi et al. (2008) , who assess the costs of Water Framework Directive‐related measures on farm accounts data, we estimate regression models allowing such costs to be predicted for any region for which land use patterns and livestock numbers are known. We derive economic impacts in terms of changes in farm gross margin for (a) reducing inorganic fertilizer application, (b) reducing livestock stocking rates, and (c) converting arable land to ungrazed grassland. A case study of the agriculturally diverse Yorkshire Derwent catchment, in the North of England, demonstrates the overall approach. In addition, for this illustration, we combine these cost estimates with prediction of the water quality changes arising from each measure, derived via an integrated hydrological model of the Derwent. This allows a comparison of cost‐effectiveness. Finally, we implement our spatially explicit approach to target the measures to specific subcatchments identified as being of particular environmental policy interest.     

Yield quality and irrigation with saline water under environmental limitations: the case of processing tomatoes in California

Irrigation with saline water has a positive impact on some quality indices of processing tomatoes, but with concomitant reductions in output quantity. This article studies the impact of the trade‐off between these two factors on optimal water management under waterlogging and costly drainage‐disposal conditions. The focus is on the content of total soluble solids as a quality measure affecting prices paid by California processors to tomato growers. A function relating quality to water and salinity applications and a quality hedonic‐price function are estimated and introduced into a static, field‐level mathematical programming model. The model calculates optimal water management under environmental regulations associated with drainage disposal in California. Findings indicate that only when the quality effect is taken into account does blending fresh surface‐water with saline drain‐water become an optimal strategy. Management and policy implications on the regional scale are discussed.     

两部制水价中基本水量对水费的影响分析

为了确定基本水量对水费收入的影响,假定同一供水工程在基本水费固定的情况下,基本水量取小于、等于和大于临界点水量3种情况,组成3组两部制水价方案,并分别与单一制水价相比较,得到3组结论,提出对实际水价方案进行优化的建议。     

Perennial crops under stochastic water supply

Perennial crops require substantial initial investment in groundwork and planting, as well as a multiyear gestation period without commercial yield. Therefore, a crop's cycle (from planting to felling) should be long enough in order to cover the fixed cost and become profitable. The problem becomes involved when the cycle's duration is stochastic due to occurrence of uncertain event that terminates the cycle prematurely. Studying orchard management under stochastic drought events, we show that to each perennial crop that is profitable without drought hazard, there exists a critical drought hazard above which the crop turns loss making. We refer to this critical drought hazard as the crop's drought vulnerability index and show that it increases with the length of the gestation period, the ratio of fixed cost to average annual profit and the interest rate, and decreases with the natural (uninterrupted) cycle length. We then investigate the economic value of a stable water source, such as recycled water, that stabilizes the water supply and diminishes the drought hazard. An empirical application in northern Israel reveals that the stabilization value of recycled water due to its role in eliminating the drought hazard far exceeds its supply cost.     

供水保证率法在水利工程水价核算中的应用

针对水利工程水价核算采用按设计供水保证率法分摊同一工程、不同供水类别的成本费用存在的不足,提出用实际供水保证率取代设计值的水价核算方法,并以引滦枢纽工程为例,计算了该工程的实际供水保证率,分析了不同供水保证率对水价核算水平的影响,指出水管单位应开展实际供水保证率测定工作,从而使我国供水工程水价核算工作更加科学、合理、符合实际。     

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.     

水资源治理与传统水利管理的区别

探析水资源治理的内涵及其与传统水利管理的区别。认为，治理与管理的最大区别在于：治理的客体是多方利益主体以及他们之间可能互不隶属的社会关系；而管理是针对一个封闭系统内部的，管理体系中的权力关系是自上而下的。人类治水活动系统包含两个子系统：处理水与人关系的自然子系统；协调人与人关系的社会子系统。中国水问题的实质是人的问题，水危机的根源在于协调处理社会子系统能力低下所导致的治理危机，治水的关键在于“治人”，在于提高对水资源的治理能力。由于要面对和处理横向的、互不隶属的社会关系，水资源治理与传统的水利管理从内容到目标、到手段，均不相同。     

Pricing Sydney water*

The paper estimates an aggregate daily water demand for Sydney using rainfall, temperature, and price data from 2001 to 2005, and a dummy variable to account for reductions in demand following the introduction of water restrictions in October 2003. Analyses based on the estimated price elasticity, and also values one and two standard errors above and below this estimate, are used to model the effects of different pricing and water supply scenarios. The simulations indicate that without a fundamental change in water policy (pricing and supply) Sydney faces the possibility of critical water shortages in the short- to medium-term should there be a continuation of low rainfall events.     

我国虚拟水及虚拟水战略研究

在总结国内外虚拟水和虚拟水战略研究进展的基础上,分析了我国虚拟水贸易流动格局,提出了适合我国国情的广义虚拟水战略,对其驱动因子做了较详细的分析,并就广义虚拟水战略在我国的实施提出相关对策和建议。结果表明,广义虚拟水战略在我国实施的直接原因是水土资源的不匹配,而根本原因与我国国民经济的总体布局密切相关,是我国经济发展的必然。