DSS Application to the Development of Water Management Strategies in Ribeiras do Algarve River Basin

Within the Project – “Developing Strategies for Regulating and Managing Water Resources and Demand in Water Deficient Regions (WSM)” funded by the EU in fifth Research Framework Program, the Ribeiras do Algarve River Basin was chosen as a case study to develop a DSS for planning purposes. Located in the southern stretch of the Portuguese territory, crucial conflicts do exist between tourist and agricultural water uses within the river basin. Additionally, there are important deficiencies in urban secondary water supply. Also inadequate irrigation methods and poor quality of water existing in some areas urge the implementation of management measures. Different ways to improve the water management situation were analysed: (a) structural options, (b) demand management options and (c) socio-economic measures. These options were analysed using a range of combinations of extreme demand and availability scenarios and ranked based on indicators reflecting the perception of the local stakeholders towards economic development and social and environmental sustainability. On a second phase, the formulation of strategies using the available options was addressed and two different strategies, resulting from a tentative timeframe of water management options combination, were applied aiming to achieve goals defined with regional stakeholders, namely: (a) on a first stage, the optimization of the domestic and irrigation water demand coverage and aquifer’s groundwater exploitation use ratio; (b) on a second stage, the determination of the water pricing increase necessary to achieve economical sustainability, aiming at cost recovery goals in accordance with the Water Framework Directive compliance.     

Water Productivity in a Rigid Irrigation Delivery System

The rotational irrigation water delivery (warabandi) system practiced in the Indus river basin of Pakistan has continued for 100 years. Irrigation water allocated to the farmers under the warabandi system is proportional to farm size and is fixed. This rigid allocation system has been partly justified by its contribution to social equity though this may have been at the cost of economic gains. In order to assess the operation of warabandi’s basic rules, a farmers’ survey was completed from 124 farmers located on five watercourses. A questionnaire was administered to each farmer and farm management data were gathered. As fresh water resources are under stress and becoming scarce their efficient use in all applications should be assured in water allocations. It is shown from the survey results that water allocation based on very limited criteria does not maximize the socio-economic benefits gained from the use of scarce water. Thus, it is suggested that the existence or non-existence of fresh groundwater resources along with other critical variables should be taken into consideration when making canal water allocation decisions. Missed water deliveries due to failure of the canal system appear to be the largest cause of losses. Water charges need to be increased to fund large improvements in canal maintenance programs. It is pointed out that a framework should be developed as a tool to improve water productivity for Pakistan. This should include: consideration of the gross area of a tertiary canal, sensitivity of crop growth stage to water shortage, crop value, bias of allocation towards most water use efficient areas and water use efficient crops, the potential losses from water deficiency.     

Water Pricing for Agricultural Production in the South of Iran

Appropriate water resource allocation in dry land area is very important for farm management. Although very few systems for water distribution have efficient pricing, water resources should be allocated so that the marginal cost equals the marginal value product of water for all uses and users. When the marginal values are not equal, it is always possible to find a reallocation of water that increases net social benefits. Microeconomic techniques used for estimating the value of water and determining farmers’ willingness to pay include: net-back analysis, hedonic models, and optimization models. The main objective of this study was to compare marginal value product of irrigation water applied to grow the selected crops in the southern Iran. We used net-back analysis to evaluate agricultural water value in the Hormozgan province (southern Iran). The empirical information is drawn from the agricultural service agencies and survey from farmer’s respondents. Data set is included quantity of output, prices, and costs of selected crops and water. The calculated net-back value for each product indicates the maximum ability to pay (MATP) or the shadow price of water used in irrigation. That is, if a farmer pays that amount for water he gets neither benefit nor loss. The results indicated that among selected crops, cucumber and lime had the highest return for water use. The most important management implication of this study is the reallocation of irrigation water according to the economic value of water in various crops.     

Impacts of Combined Technical and Economic Measures on Water Saving in Agriculture under Water Availability Uncertainty

In Emilia Romagna region (northern Italy), the Water Protection Plan (WPP) — a tool designed to reach the objectives of the Water Framework Directive — established different measures to achieve a good quantitative status of water bodies. The objective of this study is to evaluate the combined economic, agronomic and environmental impacts of four measures of the WPP on the “Renana” reclamation and irrigation scheme, and to quantify the water conservation in agriculture under the uncertainty of water availability. To this purpose, a mathematical stochastic model able to represent uncertainty in water availability was designed and implemented. Some data were collected from farms, and local sources were used as well to test the model. Each analyzed measure was simulated in a single scenario, and subsequently combined with other measures. The performed simulations are the following: application of volumetric water pricing (Scenario WFD1), awarding incentives for farmers to improve on-farm irrigation efficiency (Scenario WFD2a), combination of WFD1 and WFD2a (Scenario WFD2b), reduction of water abstraction in case of water shortage (Scenario WFD3a), combination of WFD1 and WFD3a (Scenario WFD3b), increasing distribution efficiency in the channel system (Scenario WFD4a) and combination of WFD1 and WFD4a (Scenario WFD4b). Results have shown that scenarios WFD2a and WFD4a generate a higher income for farmers and produce a positive ecological impact (water use and soil cover) but tend to increase total water use. Scenarios WFD1 and WFD3a have the opposite effects since they reduce farmers’ income but decrease water use as well. Only WFD1 could be favorable for the Board governing the scheme (RIB) in terms of economic returns. Finally, results have shown that combined scenarios WFD2b and WFD4b, respectively, could modify the trade-off between economic and environmental objectives and could be more effective since they significantly reduce water consumption and minimize losses in farmers’ income.     

Hydrological Impacts of Flood Storage and Management on Irrigation Water Abstraction in Upper Ewaso Ng’iro River Basin, Kenya

The upper Ewaso Ng’iro basin, which starts from the central highlands of Kenya and stretches northwards transcending different climatic zones, has experienced decreasing river flows for the last two decades. The Naro Moru sub-basin is used to demonstrate the looming water crisis in this water scarce river basin. The objective of the study was to show the extent of dry seasons’ irrigation water abstractions on river flows, and to assess the hydrological impact of flood storage on temporal water distribution and irrigation water management. Decreasing river flows are attributed to over-abstraction mainly for irrigating horticultural crops. The number of abstractors has increased four times over a period of 10 years. The amount of water abstracted has also increased by 64% over the last 5 years. Moreover, the proportion of unauthorized abstractions has been increasing over the years, currently at about 80% and 95% during high and low flows respectively. This has resulted in alarming conflicts among various water users. The situation is aggravated by low irrigation efficiency (25–40%) and inadequate flood storage facilities. The paper analyzes over 40 years’ observed river flow data and 5-year interval water abstraction monitoring records for 15 years. It assesses whether flood storage and management, can reduce dry seasons’ irrigation water abstractions without significantly reducing river flows to affect the sustenance of natural ecosystems downstream. The results demonstrate that flood storage and management can reduce water abstraction and increase river flows during the dry seasons, without significantly reducing high flows to affect the downstream water users. However, socio-economic, hydrological and environmental implications should be considered if a sustainable river basin water resources management strategy is to be developed and implemented. The case study of Naro Moru sub-basin is representative of the situation in the other sub-basins, and hence can be taken as a pilot basin for developing an integrated water resources management strategy that will foster socio-economic development with minimal negative hydrological impacts in the water scarce upper Ewaso Ng’iro river basin.     

A Coupled Water Quantity–Quality Model for Water Allocation Analysis

As the demand for water continuously increases with population growth and economic development, the gap between water supply and demand in China has become increasingly wide. In recent years worsening water pollution has caused this gap to become much more serious. Conventional allocation pattern, which mainly considers water quantity as the key factor, is no longer satisfying the water allocation need. A coupled water quantity–quality model in a river basin is presented in this paper to provide a tool for water allocation schemes analysis. The pollutants transport and hydrological cycling processes in a river basin are involved in the model. A river network is divided into different reaches. According to the division of river network, the areas out of the river are divided into a series of tanks. In each tank, hydrologic processes, pollutant loading production, water demand of users and water supply are calculated. In river network, hydrodynamics processes and water quality are simulated. Water quantity and quality exchanges between each tank and river are also considered. The time step of water quality calculation is 24 h, the same with that of water quantity calculation. In each time step period, the connections of river reaches and tanks are realized through the exchange of water quantity and quality between rivers and tanks: pollutants discharge from tanks to rivers and water intake from rivers to satisfy water demand in tanks. The water use in each tank includes three types: domestic, industrial and agricultural water use. Water allocation schemes are one of the input conditions of the model. Using the proposed model, in each tank, water demand and deficit of different uses, in both water quantity and quality, can be obtained under different water allocation schemes. According to the water deficit, water allocation schemes are analyzed to make proper allocation schemes. In this aspect, the proposed model can also be thought as a water allocation model. The model is tested and applied to the Jiaojiang River basin, Zhejiang Province, China, to analyze the different water resource allocation schemes.     

Improving Operational Performance of Farmers Managed Distributary Canal using SIC Hydraulic Model

Operation of a secondary canal was recently transferred to the farmers’ organization (FO) under irrigation management transfer (IMT) programme. After modernization of Upper Swat Canal (USC) irrigation system, the water allowance was increased to operate the irrigation system more in demand responsive mode. The study of the existing operation of the canal revealed that most of the time the irrigation supplies exceed the demand and the farmers either over irrigate their fields or waste precious irrigation water. Operation and management aspect of the irrigation system play a pivotal role in overall water management practices. SIC hydrodynamic model was employed to evaluate the operational performance of the distributary. Different operational scenarios were investigated and quantified based on fixed frequency operation. Based on these results it is suggested to operate the distributary at 80–90% of the design discharge during May to July, and 75–90% of the design discharge from August to April to reduce water losses due to high water allowance.     

长江流域用水状况分析

简要介绍了长江流域水资源二级分区、水资源量等情况.利用1998～2002年长江流域水资源公报汇总资料,着重分析研究了长江流域及其流域各二级区的用水组成情况,农业用水量、工业用水量和生活用水量在总用水量中所占比重,研究了用水量年际间和各二级区间的变化特点和规律.分析计算了长江流域人均综合用水量、万元GDP用水量、农田灌溉平均用水量和人均生活用水量等用水指标,分析了二级区间用水指标的变化情况.通过分析研究,提高了对长江流域用水情况的认识.     

Investment in Irrigation Systems under Precipitation Uncertainty

Efficient agricultural water management is indispensable in meeting future food demands. The European Water Framework Directive promotes several measures such as the adoption of adequate water pricing mechanisms or the promotion of water-saving irrigation technologies. We apply a stochastic dynamic programming model (SDPM) to analyze a farmer??s optimal investment strategy to adopt a water-efficient drip irrigation system or a sprinkler irrigation system under uncertainty about future production conditions, i.e. about future precipitation patterns. We assess the optimal timing to invest into either irrigation system in the planning period 2010 to 2040. We then investigate how alternative policies, (a) irrigation water pricing, and (b) equipment subsidies for drip irrigation, affect the investment strategy. We perform the analysis for the semi-arid agricultural production region Marchfeld in Austria, and use data from the bio-physical process simulation model EPIC (Environmental Policy Integrated Climate) which takes into account site and management related characteristics as well as weather parameters from a statistical climate change model. We find that investment in drip irrigation is unlikely unless subsidies for equipment cost are granted. Also water prices do not increase the probability to adopt a drip irrigation system, but rather delay the timing to invest into either irrigation system.     

Estimating the Impact of Water Pricing on Water Use Efficiency in Semi-arid Cropping System: An Application of Probabilistically Constrained Nonparametric Efficiency Analysis

By introducing proper pricing instruments, farm level water can be used more efficient. But it demands a proper estimation strategy to analyse the efficiency and the input use behavior of farms under the new pricing system. As most production relationships are stochastic in nature, excluding random errors and noise from model specifications often leads to criticism. By using a probabilistically constrained programming formulation, an empirical estimation of stochastic data envelopment analysis (DEA) is done to analyze the efficiency of irrigation water use in the agricultural production system in the Krishna river basin, India. The results illustrate that water demand is higher for farms at, or close to the frontier and lower for those with low efficiency levels. In a second step, a simulation model is developed by using the frontier and economic efficiency derived from stochastic DEA to analyse the impact of water pricing on water use efficiency and water use behaviour. It is shown that an increase in the water price would not cause sizeable profit loss, if the pricing system is administered on a volumetric basis, but water demand would decrease substantially.     

基于水文-作物耦合模型和CWAPI指数的农业干旱评估

基于模拟土壤含水量构建的干旱指数可反映农业干旱的时空发展过程,已被广泛用于大范围农业干旱评估中。当前模拟用于干旱评估的土壤含水量时,常采用水文模型进行模拟。然而,水文模型常过于简化作物模块甚至缺少作物模拟方案,无法模拟作物需水量,因此仅基于土壤含水量构建的土壤干旱指数因忽略作物需水而难以准确评估实际的农业干旱情况。研究构建了考虑灌溉过程影响的水文-作物耦合模型VIC-EPIC（Variable Infiltration Capacity-Environmental Policy Integrated Climate）,提出了基于VIC-EPIC模拟作物需耗水过程的作物缺水距平指数CWAPI（Crop Water Anomaly Percentage Index）,在青口河流域开展了区域农业干旱评估方法研究。验证分析表明,构建的CWAPI因考虑作物需水影响可直接反映作物的缺水状态和缺水对作物生长的累积影响;由于在干旱评估中引入了作物种植比例、轮作类型和灌溉的影响,CWAPI能够较SMAPI（Soil Moisture Anomaly Percentage Index）更客观地反映区域作物旱情。因此评估农业干旱时,需要考虑作物种植比例、轮作和灌溉过程的影响。     

注重干旱区河谷林草生态保护与修复的漓漫灌溉研究

为提高干旱地区灌溉效率,保障河谷林草的正常生长,本文以额尔齐斯河流域为研究对象,深入阐述了漓漫灌溉理论,提出了漓漫灌溉主要技术。据此分析计算了流域内河谷林草的生态需水量,制定了河谷林草的漓漫灌溉制度,相比传统的农业灌溉,更注重于考虑生态的修复和保护。计算结果表明:(1)河谷林草的生态需水集中在4—9月,且缺水量最大在6月下旬—7月上旬,为漓漫灌溉生态调度起始时间的界定奠定了技术支撑;(2)生态工程布置和漓漫灌溉分区确定的生态工程与灌区一一对应的靶区漓漫灌溉模式有助于改善河道外植被的供水条件,保证河谷林草最大程度地吸纳水分;(3)制定的漓漫灌溉制度可为灌溉工程规划设计以及灌区用水管理提供依据。在实施漓漫灌溉后,通过生态工程和非工程措施实现了河谷林草的生态保护目标,流域内河谷林草的生态得到有效恢复和改善。研究成果对促进流域河谷林草、湿地等生态目标的改善和实施具有重要的理论意义和实用价值,为确保流域社会经济用水与生态用水之间的相对均衡、保护与修复流域内河谷林草的生境提供了技术支撑。     

Water use characteristics and impact factors in the Yellow River basin,China

ABSTRACT

This study focuses on the water use characteristics and impact factors in the Yellow River basin. Water use increased from 1980 to 2000 and then stabilized. Water use in the eight regions of the basin varies significantly in both time and space. Water use in different sectors is sensitive to variations in the irrigation area, industrial added value, efficiency, population and urbanization. Change trends are the results of the joint effects of supply-and-demand relationship and water policy. Water use is insensitive to precipitation, because irrigation mainly relies on river water and groundwater.     

Basin-wide Water Resources Planning by Integrating PSO Algorithm and MODSIM

Water resources planning and management at basin scale is such a large and complex problem that makes it essential to use effective modeling tools in order to obtain an optimum plan for river basins development. In this paper, a methodology is presented for optimized design and operation of the upstream Sirvan basin in Iran. The model proposed integrates MODSIM generalized river basin network flow model, with the capability of simulating various characteristics and features of water resources in a river basin, and Particle Swarm Optimization (PSO) algorithm. In the developed PSO-MODSIM model, the size of planned dams and water transfer systems, as design variables, and the relative priorities for meeting reservoir target storages, as operational variables, are varied and evolved using PSO algorithm. MODSIM is called to simulate the system performance and to evaluate the fitness of each set of those design and operational variables with respect to the model’s objective function. The PSO objective function is to maximize the total net benefit consisting of benefits due to supplying water to different types of water uses and construction costs of dams and water transfer and/or pumping systems. Varying the design and operational variables in MODSIM 8 is done using the MODSIM’s custom coding feature in VB.NET routine. The PSO-MODSIM model is used to size the planed water storage and transfer components of a river basin system and to allocate water resources optimally over time and space among competing demands, considering coordinated operation of the system components. The model results has been analyzed for different scenarios of water transfer from Sirvan to neighboring basins.     

Water Allocation as a Planning Tool to Minimise Water Use Conflicts in the Upper Ewaso Ng’iro North Basin, Kenya

Inadequate water resources management and a general decline in rainfall have aggravated water scarcity problems in the Upper Ewaso Ng’iro North Basin in Kenya. Furthermore, water use conflicts in the basin have escalated in recent decades due to increased competition for available water resources. Excessive abstraction of the declining river water mainly for irrigation in the Mount Kenya and Nyandarua foot zones often leads to reduced water flow during the dry seasons, greatly affecting downstream water users. Increased water use in the basin coupled with deterioration of the vegetative cover has resulted in reduced water flows in the Ewaso Ng’iro river and its major tributaries. In addition, lack of sufficient knowledge about available water resources and current lack of coordination in water resources management in the basin often result in water deficits which have hampered development in the downstream catchment. The goal of this study was to match the water requirements of various competing sectors in the basin with the available water resources in order to attain both economic and ecological sustainability. To achieve this, GIS techniques were used to quantify the spatial and temporal stream flow. The Water Evaluation and Planning (WEAP) model was applied to evaluate water resources development based on an equilibrium scenario of the current water demand. Water use was simulated for five different sectors (domestic, livestock, wildlife, irrigation and reserve). The analyses revealed that high water demand for irrigation was the main cause of excessive water abstraction particularly in the upstream catchments, giving rise to water shortages and consequently, water use conflicts downstream. The study, therefore, recommends that rainwater harvesting be promoted in the basin in order to improve water availability for productive use.     

对农业水资源费和水费问题的思考与建议

随着国家取消农业税以及逐步取消乡统筹、村提留等收费项目，农业水资源费和农业水费问题成为当前农村的一个热点。农业水费在农业生产成本中的比例不断上升，但灌溉带来的增收效益明显。农业种粮收入低是造成农业水价改革难的关键因素。建议抓紧制定农业生产用水定额，推进节水型农业建设，继续深化农业水价改革，加大政府扶持力度，强化农田水利对农业的支持保护作用。     

Agricultural Water Use in Turkey

Abstract

Agriculture is the largest user of water in Turkey with 75 percent of the total consumption. Turkey has developed 50 percent of total irrigable land so far. Water is a limiting factor for agriculture throughout much of Turkey. The amount and distribution of precipitation is quite uneven. Turkey, like many countries today, faces challenges in efficiently developing and managing its agricultural water resources while trying to protect water quality and the environment. However, Turkey has some difficulties and problems on water use for agriculture. Current institutional framework and legal regulation, monitoring and evaluation activities are investigated, and agricultural water use and irrigation development are studied. Problems with the lack of data on environmental effects of irrigation and water pricing are underlined. Evaluation of the current situation ends in the conclusion that Turkey needs a comprehensive monitoring and evaluation system both at basin and scheme level, and rehabilitation of irrigation systems for efficient water use in agriculture.     

Value of Irrigation Water in Guadalquivir Basin (Spain) by Residual Value Method

This paper presents an application of residual value techniques to the economic analysis of irrigation water at the basin level for the Guadalquivir River (Southern Spain). The methodology is simple; the results are robust and consistent with alternative method findings. The average residual value in the basin is 0.31 €/m³ and according to the to Residual Value Method, the distribution of total Gross Value Added (GVA) of irrigated land is distributed between the different factors of production as follows: (i) water, 62% of GVA; (ii) land, 20% GVA (from rain-fed productivity), (iii) return to man-made capital, 5% GVA; and finally (iv) the pair ‘management + family-labour’ gets 13% of total irrigation GVA. The paper illustrates the use of this method for the whole basin and it shows that it may offer promise for supporting sustainable water management at the basin (or the local) scale. It may be used for the implementation of the Water Framework Directive.     

The Cost of Irrigation Water Delivery: An Attempt to Reconcile the Concepts of Cost and Efficiency

This work discusses the conflict between two of the main objectives of the EU Water Framework Directive: cost recovery and economic efficiency in the use of irrigation water. In the Mediterranean region, this conflict is commonly embedded in a state of under-utilization of irrigation networks managed by Water User Associations (WUAs). This under-utilization arises from factors independent of farmers’ choice, such as water shortage, crises in the sector, and changes to the Common Agricultural Policy. This prevents the facilities from operating at the minimum average cost. This paper argues that farmers should not suffer this inefficiency, which results in them paying higher water prices to cover the costs of water supply. Indeed, the application of the Water Directive should be rethought, taking into account the specific problems related to irrigation in the Mediterranean region. Based on an econometric analysis of the costs of water distribution in a WUA in Sardinia (Italy), we propose a payment system based on two components. Primarily there is a fee related to the number of hectares under irrigation. In addition there is a fee that considers the intensity of irrigation: this component is to encourage farmers to save water. The results show that the proposed approach has some desirable effects, including higher rates of cost recovery and possibly a reduction in the use of groundwater. Finally, the proposed system is not overly expensive for the rest of the community, who must bear the costs of inefficiencies in the use of irrigation water that do not depend on choices of farmers.