Farm-level perspectives regarding irrigation water prices in the Tulkarm district, Palestine

Agriculture consumes about 70% of water available in the Occupied Palestinian Territories. Domestic and industrial users utilize 30% of the water supply. Water resource managers are considering the policy of reallocating a portion of the water supply from agriculture to other uses. It is believed that increasing irrigation water prices could influence water consumption and thus make water available for non-agricultural (more economic) uses. This paper examines the impacts of water pricing on agricultural water consumption and farming profitability and provides some guidelines for policy makers regarding water pricing as a tool to manage scarce water resources. We estimate a regression model describing agricultural water consumption as a function of water prices, irrigated land area, farm income, and irrigation frequency, using data collected in a survey of about 150 farmers in the Tulkarm district. We conclude that irrigation water prices are perceived as high and comprise a large portion of total farming expenses. Therefore, attempts to increase irrigation water prices in the Tulkarm district might jeopardize farming feasibility and might have substantial impacts on agricultural water consumption. Nevertheless, many farmers would continue farming even if the water prices were increased beyond their willingness to pay threshold.     

Water markets and soil salinity nexus: Can minimum irrigation intensities address the issue?

Agricultural water markets can facilitate adjustments to water scarcity and competition and enhance economic efficiency, but markets cannot automatically balance efficiency, equity and environmental sustainability goals. The consequences of water trading on soil salinity in irrigation areas are not yet fully understood, but recognized as an issue that needs to be analysed. This paper explores the nexus between water trading and groundwater-induced soil salinity in a selected irrigated area in the Murray-Darling Basin. Results show that minimum irrigation intensities must be met to flush salts out of the root zone especially in shallow water table/high salinity impact areas. Such minimum irrigation intensities are helpful but not necessarily in deep water table/low salinity impact areas. Should water markets lead to permanent water transfers out of mature irrigation areas, minimum irrigation intensity needs might not be met in high salinity impact areas, causing substantial negative impacts on resource quality and agricultural productivity. Water trading that adds to salinity cannot be economically viable in the long run. The tradeoffs between water trading and environmental and equity goals need to be determined. This work contributes to the wider debate on Australian water policy aimed at achieving water security through water trading in the Murray-Darling Basin.     

Performance based irrigation planning under water shortage

A linear programming (LP) based optimization model and a simulation model are developed and applied in a typical diversion type irrigation system for land and water allocation during the dry season. Optimum cropping patterns for different management strategies are obtained by the LP model for different irrigation efficiencies and water availability scenarios. The simulation model yields the risk-related irrigation system performance measures (i.e. reliability, resiliency and vulnerability) for the management policies defined by the optimization model. The alternative strategies are evaluated in terms of all performance criteria (i.e. net economic benefit, equity and reliability) simultaneously through a trade-off analysis using a multi-criteria decision making method (compromise programming). For the case study of the Kankai irrigation system in Nepal, with equal preference to the objectives, a management strategy with equal share of water among the project subareas appears to be the most satisfactory alternative under water shortage conditions. The existing water allocation policy is not economically efficient. Deficit irrigation in Early paddy appears attractive under favorable hydrologic scenario, particularly if accompanied by measures to improve existing irrigation system efficiency.     

Valuing irrigation water using survey-based methods in the Tungabhadra River Basin, India

The paper discusses the challenges in using survey-based methods of economic valuation of water: choice experiments, residual value of water and water trading prices. The three different approaches to economic valuation of irrigation water are compared, all based on data from a farmer survey conducted in two irrigation command areas in the Tungabhadra sub-basin (Karnataka State, India). Prices reported by farmers for sale and purchase of an additional irrigation are of the same order as willingness to pay estimates derived from a choice experiment. Because of small number of water trades there is large variation in market-price based estimates. Financial returns to a given crop as a function of irrigation frequency show values that are both lower (for rice) and higher (for areca nut) than choice experiment estimates. Low convergent validity of different economic valuation methods of irrigation water, is in part due to the large variation in water availability and farm conditions across the watershed, but also because of methodological weaknesses. While recognizing these weaknesses, the paper shows that representative farm surveys using a combination of valuation methods can identify heterogeneity in farm conditions and preferences that may otherwise be overlooked when carrying out irrigation pricing reform.     

Optimisation model for water allocation in deficit irrigation systems: I. Description of the model

In this paper, an economic optimisation model for hydrologic planning in deficit irrigation systems is proposed. Irrigation water allocation between agricultural demands is carried out following an economic efficiency criterion with the aim of maximising the overall economic benefits obtained, allocating available water to each user as a function of the water’s profit margin. Water resources constraints in the system are considered. Aggregated economic functions for each irrigation district are generated optimising the water used for the cropping pattern. Stochastic nature of water availability and irrigation requirements have been taken into account.Due to the complexity of the system, the problem has been broken down into three independent optimisation sub-problems that perform hierarchically. Each of these sub models takes into account a different resolution level of the system: crop, irrigation district and the whole basin.The proposed model has been used in a subsequent paper to optimise water allocation planning in a small basin in southern Spain; the Bembézar system.     

Integrated hydrologic-economic modelling for analyzing water acquisition strategies in the Murray River Basin

We describe a coupled hydrologic-economic spreadsheet model for the Murray-Darling Basin that allows analyses of water allocation and use by different sectors including agriculture and environment under alternative policy scenarios. The model is a simple, lumped optimisation model which includes partitioning of rainfall into runoff and evapotranspiration, a reach by reach water balance of the river system, irrigation demand and revenue generation. Groundwater is not considered because groundwater use is a small part of the overall water use. The model is used to optimize profit, diversions and flows subject to hydrological and economic constraints determined by the policy scenario.We use the model to examine approaches of acquiring water for reallocation to the environment, and their impacts on irrigation water use and regional income from agriculture. We show that the optimal approach for acquisition depends on: economic factors, including the cost of water and the profits generated by its use; institutional factors, such as restrictions to trade between regions; and, hydrological factors, particularly the connectivity of and losses within the river network.The volume of water to be acquired does not, in general, equal the volume to be allocated. For a downstream site, water must be acquired from upstream, and more water must be acquired than is to be allocated: the volume acquired is that to be allocated plus transmission losses between the locations of acquisition and allocation. For upstream sites, it is optimal to acquire some water from downstream, and less water must be acquired than is to be allocated: the volume acquired is that to be allocated, less the transmission losses no longer incurred between the locations of acquisition and allocation.The volumes of water that must be acquired to satisfy an allocation target and maintain flows in the river system are affected by restrictions on trade between sub-catchments.     

Water demand and flows in the São Francisco River Basin (Brazil) with increased irrigation

Most activities that support economic growth in the São Francisco River Basin (Brazil) need water. Allocation of the water resources to each competing use needs quantification in order to develop an integrated water management plan. Irrigation agriculture is the largest water consuming activity in the basin. It has produced large economic and social advancements in the region and has potential for further development. The local development agency in the São Francisco River has projected an increase of more than 500,000 ha in irrigation developments distributed within the basin.Water requirements of the projected irrigation expansions and their effects on river flow were quantified. A semi-distributed model was constructed to simulate the water balance in 16 watersheds within the basin. The watersheds were hydrologically characterized by the average precipitation, atmospheric demand and runoff as well as their variability. Water requirements for increased irrigated agriculture were calculated using an agronomic mass balance. A Monte Carlo procedure generated the variability of irrigation requirements and resulting decreased river flows from the multidimensional probability distribution of the hydrologic variables of each watershed.Irrigation requirements were found to be more variable during the wet season because of weather variability. In contrast to what might be expected, in drier years, irrigation requirements were often larger during the wet season than in the dry season because the cropped area is largest in the wet months and variability of precipitation is greater. Increased irrigation shifted downward the distribution of river flows but not enough to affect other strategic water uses such as hydropower. Further irrigation expansion may be limited by wet season flows.     

Exploring regional irrigation water demand using typologies of farms and production units: An example from Tunisia

Most methods used to predict irrigation water consumption at a regional scale are based on biophysical models and cropping patterns. Their aim is to provide accurate estimations of “water demand” that are useful for water resource management. However, in the case of free access to the water resource, for example pumping from a water table, it is only possible to prevent overexploitation by “managing” the demand for water, which thus needs to focus on farmers’ choices and behavior. In this paper, we propose a framework to represent agricultural activities using typologies of farms and production units aggregated at a regional scale. The framework can be used to estimate consumption of irrigation water and of other inputs, as well as the production of outputs. The framework can also be used to evaluate the effects of technical, economic or institutional changes on farm income, and to predict the consequences of changes for farmers’ choices at regional scale. We used this method in Central Tunisia to estimate irrigation water demand in 1999. We then simulated the changes that would occur if drip irrigation were adopted. The results of the simulation showed some savings in water and in labor, and, with fertigation, an increase in yields. Using drip irrigation would consequently enable farmers to extend the area of drip-irrigated land. We then simulated the widespread adoption of drip irrigation and the resulting extension of irrigated areas: the results showed no savings in water at the regional scale. These hypotheses were confirmed in 2005 using new typologies to estimate the new demand for irrigation water. We also simulated the effects of economic changes on farm incomes. A major increase in the cost of water affected a minority of farms, which consumed only 17% of total irrigation water, whereas a slight decrease in watermelon and melon prices affected a majority of farms, which consumed 78% of total irrigation water. Water demand management tools therefore need to focus on the effects of technical, economic, or institutional changes and on farmers’ choices.     

Enhancing water policy discussions by including analysis of non-water inputs and farm-level constraints

Water resource professionals have many opportunities to contribute to policy discussions regarding agricultural productivity. Often those discussions are focused on increasing the output generated with limited water supplies, such as maximizing the “crop per drop” or improving irrigation efficiencies, either at the field level or throughout a river basin. Policy discussions involving water resources in developing countries can be enhanced by placing greater emphasis on the roles of non-water inputs and resource constraints in farm-level production and marketing decisions. Three categories of policies that lie outside the water resource realm, but have substantial impacts on water use and agricultural productivity, are examined: (1) policies that modify farm-level input and output prices directly; (2) international trade policies; and (3) policies that modify key institutions, such as land tenure and the sources of investment funds.     

Establishing tradable water rights: implementation of the Mexican water law

Mexico passed a new water law in 1992 that shifted from state-managed water policy to a regulated market-oriented policy with tradable water rights. Water trading will initially be closely supervised by government agencies, but the law includes a number of provisions that will allow liberalization of water markets as water users become more involved in operation and management of water and gain experience in water trading. Incentives for the Mexican water policy reforms include the growing economic value of increasingly scarce water; the rising budgetary costs from highly subsidized capital development and operations and maintenance for irrigation and water supply systems; and general liberalization of the Mexican economy, which has raised the cost of maintaining relatively inflexible water allocation systems that cannot respond to changing incentives.     

Impacts of population growth, economic development, and technical change on global food production and consumption

Over the next decades mankind will demand more food from fewer land and water resources. This study quantifies the food production impacts of four alternative development scenarios from the Millennium Ecosystem Assessment and the Special Report on Emission Scenarios. Partially and jointly considered are land and water supply impacts from population growth, and technical change, as well as forest and agricultural commodity demand shifts from population growth and economic development. The income impacts on food demand are computed with dynamic elasticities. Simulations with a global, partial equilibrium model of the agricultural and forest sectors show that per capita food levels increase in all examined development scenarios with minor impacts on food prices. Global agricultural land increases by up to 14% between 2010 and 2030. Deforestation restrictions strongly impact the price of land and water resources but have little consequences for the global level of food production and food prices. While projected income changes have the highest partial impact on per capita food consumption levels, population growth leads to the highest increase in total food production. The impact of technical change is amplified or mitigated by adaptations of land management intensities.     

SIDD的实践与思考

分析了我国现阶段灌区管理现状，介绍了国外代表性的灌区管理模式，针对我国的实际情况，提出了一种较为先进的农业灌溉管理模式，即体现经济自立，视水为商品的SIDD模式，并根据国内几个灌区SIDD的实践，评价了SIDD试点的成效，探索了存在的典型问题与对策。     

Economic impacts on farm households due to water reallocation in China's Chaobai watershed

Our study area in the Chaobai watershed, upstream of Miyun Reservoir, has been undergoing agricultural water transfers to downstream municipal uses in Beijing. We examine the impacts of water reallocation on crop production and farmers’ income and discuss issues relating to current compensation mechanisms. We use data from a survey of 349 farm households and their farm plots in the upper Chaobai watershed within Hebei province. Water reallocation from upstream to downstream areas has reduced agricultural water supply and the area irrigated. Regression results show that in plots deprived of irrigation, maize yields decrease by 21% and crop revenues decline by 32%. On average, losing irrigation on one hectare of cultivated land reduces net crop income by 2422 yuan. We examine compensation arrangements and social equity for the major policies implemented in the region and we identify gaps between current compensation levels and farmers’ income and production losses. The current compensation received by farmers is generally lower than the losses incurred due to reduced irrigation. A more appropriate compensation mechanism is called for in future water transfers.     

Removing barriers to facilitate efficient water markets in the Murray-Darling Basin of Australia

We discuss the role and characteristics of water markets in Australia in facilitating efficient water allocation. Administrative, regulatory and/or political barriers to effective functioning of water markets are reviewed with a focus on the southern Murray-Darling Basin (MDB) region of Australia. A mathematical model is developed to estimate the costs of existing restrictions and the benefits from potential changes in water markets (e.g., removing barriers in temporary water markets). The modelling results reveal that expanding trade leads to an increase in mean annual net returns from AU $2502 million to AU $2590 million (i.e., an increase of AU $88 million). When the current volume restrictions, exchange rates, and trading charges are accounted for, mean annual net returns reduced from AU $2590 million to AU $2573 million (i.e., a reduction of AU $17 million). The exclusion of any of the three southern MDB states from the interstate water trading imposes significant costs. If South Australia, New South Wales or Victoria withdraws from the water market, net returns are reduced by AU $27 million, AU $31 million and $63 million, respectively. The paper outlines the policy implications of strategies to remove market barriers and to facilitate efficient and effective water trading.     

Farmers’ incentives to save water with new irrigation systems and water taxation—A case study of Serbian potato production

Drip irrigation systems and irrigation strategies like deficit irrigation (DI) and partial root drying (PRD) are potential water saving irrigation systems and strategies. This paper analyses the Serbian farmer's economic incentive to use these water saving systems and strategies instead of the present sprinkler irrigation. The analysis is a partial budgeting analysis, based on irrigation application efficiency from the literature, standard figures for power requirements, pumping efficiency and friction losses for various sources of water and pressure requirements, yields and water use from recent Serbian field experiments, as well as prices and cost structures for potatoes collected in the Belgrade region. The analysis shows that changing the present system and strategy can save a significant amount of water (almost 50%). At the same time, however, irrigation costs are also significantly increased (more than doubled), and the total production costs are increased by 10% (deficit drip irrigation) and 23% (PRD). Increased taxes on water, investment subsidies, increased energy prices, and an increased yield or yield quality may provide incentives for farmers to change to new systems and strategies. The analysis indicates that a 0.80 to 1.97 € m⁻³ water tax is needed to make deficit drip irrigation and PRD profitable. The socioeconomic cost of providing water for irrigation and the alternative value of saved water are probably not that high. Thus, water taxation may not be a socioeconomic efficient means to improve the irrigation water productivity of Serbian potato production. Drip irrigation and PRD may, however, also increase the yield quality, and a 10-23% quality premium (price increase) is needed to make deficit drip irrigation and PRD profitable.     

Position of the Australian horticultural industry with respect to the use of reclaimed water

Australia is the driest inhabited continent on earth, and pressure on its water resources is already high and increasing. Environmental, social, and economic drivers are forcing horticultural industries in Australia to reassess their use of freshwater resources. Reclaimed water is potentially a major resource for the horticultural industry. In general, however, there has been some apprehension towards using reclaimed water for irrigation, owing primarily to uncertainties related to agricultural sustainability and human health. Here, we consider the current standing of the Australian horticultural industry in terms of its preparedness to use reclaimed water for irrigation. We address issues related to policy, economics, market access, pragmatic directives (such as state and federal guidelines), environmental impact, agronomic sustainability, and public health. From these appraisals, we have attempted to summarise the major impediments to the use of reclaimed water by the Australian horticultural industry. These are: insufficient knowledge of impacts on market access; commitment to provide continuity of quality and supply to markets; implications of substitution of alternative water sources on security of supply; insufficient knowledge of food safety issues; inadequate understanding of consumer perceptions; and uncertainty about pricing of reclaimed water.     

A Farmer-Centered Analysis of Irrigation Management Transfer in Mexico

With the rewritten Article 27 of the Mexican Constitution and the National Water Law of 1992, Mexico embarked on an ambitious program of transferring the management of many irrigation systems to local user groups, primarily farmers. By 1996, 372 water user associations had been formed to control water delivery to 2.92 million hectares. During this time water prices increased by 45–180% and government O&M subsidies were eliminated. Limited economic analysis of stakeholder impact has been conducted of the irrigation management transfer (IMT) program. This research effort pilots a partial budget analytical framework for analyzing the social benefits and costs of IMT. Two irrigation modules near Culiacan, Sinaloa were selected as case studies. Results reveal that even with significantly higher water prices, water users have invested more in their systems than during the post-IMT period and consider their overall irrigation costs to be lower. Lower transaction costs in the pre-IMT period explain the majority of these cost savings. Efforts to quantify incremental benefits and costs associated with IMT at the module and district levels proved difficult given the unavailability of reliable, time series information.     

Irrigation management under water scarcity

The use of water for agricultural production in water scarcity regions requires innovative and sustainable research, and an appropriate transfer of technologies. This paper discusses some of these aspects, mainly relative to on-farm irrigation management including the use of treated wastewater and saline waters. First, the paper proposes some concepts relative to water scarcity, concerning aridity, drought, desertification and water shortage, as well as policies to cope with these water stressed regimes. Conceptual approaches on irrigation performances, water use and water savings are reviewed in a wide perspective. This is followed by a discussion of supply management to cope with water scarcity, giving particular attention to the use of wastewater and low-quality waters, including the respective impacts on health and the environment as water scarcity is requiring that waters of inferior quality be increasingly used for irrigation. The paper then focuses on demand management, starting with aspects relating to the improvement of irrigation methods and the respective performances, mainly the distribution uniformity (DU) as a fundamental tool to reduce the demand for water at the farm level, and to control the negative environmental impacts of over-irrigation, including salt stressed areas. Discussions are supported by recent research results. The suitability of irrigation methods for using treated wastewaters and saline waters is analysed. Supplemental irrigation (SI) and deficit irrigation strategies are also discussed, including limitations on the applicability of related practices. The paper also identifies the need to adopt emerging technologies for water management as well as to develop appropriate methodologies for the analysis of social, economic, and environmental benefits of improved irrigation management.     

Integration of economic and hydrologic models: Exploring conjunctive irrigation water use strategies in the Volta Basin

We describe the development, calibration and preliminary application of a dynamically coupled economic–hydrologic simulation–optimization model ensemble for evaluating the conjunctive use of surface and groundwater in small reservoir-based irrigation systems characteristic of the Volta Basin, Africa. We focus on a representative small reservoir-irrigation system located in the Antakwidi catchment in Ghana. The model ensemble consists of the physical hydrology model WaSiM-ETH and an economic optimization model written in GAMS. Results include optimal water storage and allocation regimes for irrigated production, given conjunctive surface water and groundwater systems. The goal of our research, conducted within the GLOWA Volta project, is to develop a decision support system for improving the management of land and water resources in the face of potential environmental change in the Volta Basin.