The Assessment of Irrigation Efficiency in Buyuk Menderes Basin

While extending irrigated areas to augment agricultural production, irrigation efficiency should be increased not only to improve the agricultural production but also to obtain the sustainable use of valuable and limited water resources. Through the use of Data Envelopment Analysis (DEA), which is a linear programming technique to determine the relative efficiency of a decision-making unit, it is possible to decide whether the use of water in an irrigation district is efficient or not. In this study, an input oriented DEA model is constituted to focus on the efficient use of inputs, and the method is applied to the irrigation districts having similar types of agriculture in the Buyuk Menderes Basin, Turkey. This paper aims to determine the efficient irrigation district(s), in other words where the application of water is the most profitable, considering two inputs; water volume supplied and the total irrigated area, and one output, the total value of agricultural production. The weight restrictions consistent with decision makers’ value judgements are added as constraints into the DEA models to prevent excessive weight flexibility assigned to inputs and outputs. The results have provided the efficiency scores of the irrigation districts and numerically delineated desired features of the irrigation districts for maximum efficiency. The analyses for three study years have inferred the robustness of the results. It is concluded that DEA is a practical tool for detecting local inefficiencies and proposing possible improvements for irrigation districts that could offer the greatest potential for growth.     

2011—2020年山东省水资源利用效率及动态分析

为进一步提升水资源利用效率,结合用水效率指标及数据包络分析法(DEA)和Malmquist指数法对2011—2020年山东省16个地市的水资源利用效率进行了定性和定量评估。结果表明：山东省用水效率相对全国总体偏高,但存在区域发展不均衡等特点。无论农业、工业还是综合用水水平,胶东半岛用水效率均为全省最高(尤其是青岛市),其次为鲁中,再次为鲁南,鲁西北用水效率最低(尤其是滨州和聊城市)。全省有8个地市(济南、青岛、淄博、烟台、济宁、威海、日照和菏泽市)DEA达到有效,且规模和技术均有效,其他8个地市未达到DEA有效,尤其是聊城市水资源综合利用效率为全省最低。2011—2020年期间,山东省全要素生产率(TFP)变化指数平均升高8.2%,用水效率整体呈上升趋势,主要受到技术进步增长的影响;其中胶东半岛的青岛、烟台和威海市增长幅度最大,均超过10%。但自2014年以来,全省TFP指数总体呈下降趋势,甚至于2019—2020年降低至1以下,因此水资源利用效率亟待提升。未来山东省有必要加大科技投入,促进技术创新,适当控制鲁西北和鲁南地区的生产规模,并加快非常规水资源的利用水平,保障水资源的可持续利...     

Quantifying the Poorly Known Role of Groundwater in Agriculture: the Case of Cyprus

Agriculture in the Mediterranean region is constrained by limited water resources and in many countries irrigation demand exceeds the renewable water supply. This paper presents a comprehensive approach to (a) quantify the consumptive green (soil moisture provided by precipitation) and blue (irrigation) water use for crop production, (b) distinguish the contribution of groundwater to irrigation supply and (c) estimate groundwater over-abstraction. A spatiotemporally explicit soil water balance model, based on the FAO-56 dual crop coefficient approach, which includes the computation of evaporation losses of the different irrigation systems, was applied to the 5,760-km² area of the Republic of Cyprus for the agro-meteorological years 1995–2009. The model uses national agricultural statistics, community-level data from the agricultural census and daily data from 34 meteorological stations and 70 precipitation gauges. Groundwater over-abstraction is quantified per groundwater body, based on the sustainable abstraction rates specified in the Cyprus River Basin Management Plan, as prepared for the EU Water Framework Directive. It was found that, on average, total agricultural water use was 506 Mm³/year, of which 62 % is attributed to green water use and 38 % to blue water use. Groundwater contributed, on average, 81 % (151 Mm³/year) to blue water use and exceeded the recommended abstraction rates by 45 % (47 Mm³/year). Even though the irrigated area decreased by 18 % during the 2008 drought year, relative to the wettest year (2003), total blue water use decreased by only 1 %. The limited surface water supply during the driest year resulted in a 37 % increase in groundwater use, relative to the wettest year, and exceeded the sustainable abstraction rate by 53 % (55 Mm³/year). Overall, the model provides objective and quantitative outcomes that can potentially contribute to the improvement of water resource management in Mediterranean environments, in the light of climate change and expected policy reforms.     

A New Model for Simulating Supplemental Irrigation and the Hydro-Economic Potential of a Rainwater Harvesting System in Humid Subtropical Climates

Here we have developed a new model to simulate supplemental irrigation and the hydro-economic potential of a rainwater harvesting system in rainfed agricultural areas. Using the model, soil moisture in rainfed crop land, supplemental irrigation requirements, rainwater storage in an on-farm reservoir (OFR) system, and surface and ground water availability were predicted. In an irrigated system, an OFR was used to harvest rainwater during the rainy season, and stored water was applied to cropland as supplemental irrigation (SI). An economic analysis was performed to calculate the benefits due to an OFR irrigation system, and gains from increased crop yield and downstream water availability in the irrigated OFR system were compared with rainfed system (i.e. no OFR). In addition, we calculated the impacts of dry and wet seasons on total value gains (grain and water gains) for irrigated and rainfed conditions and performed a sensitivity analysis to quantify the impacts of model input parameters on total value gains. Analyses showed that the OFR system can produce crop yields three times greater than rainfed agriculture. During a water stress season, the total water use in the irrigated system was 65 % greater than for the rainfed system. Water use efficiency of the irrigated system was 82 % higher than for the rainfed system. In a dry season, the total value gains due to increased crop yield by supplemental irrigation and downstream water availability of the irrigated system were 74 % greater than for the rainfed system, while in a wet season the total value gain of the irrigated system was 14 % greater than for the rainfed system. A precipitation scenario analysis of wet and dry seasons indicated that the benefits of a rainwater harvesting system can be considerably greater in dry seasons than wet seasons.     

Effect of Various On-Farm Water Management Scenarios on Equity and Productivity in Irrigation Networks

This research investigated the optimum on-farm water management methods for a summer crop (Maize). Water equity and productivity were optimized simultaneously by using genetic algorithms in Doroodzan Irrigation Network. Increase in water reduction fraction (WRF) (0.0 to 0.8) has the incremental effect on water equity (on average 19.4 %), however by increasing WRF, water productivity initially increased (on average 25.3 % at WRF?=?0.4) and then decreased. With increasing irrigation application efficiency (E_a) (40 to 90 %), the values of water equity and productivity increased by on average 52.8 and 91.5 %, respectively. Increment of conveyance efficiency of channels (E_c) (70 to 90 %) resulted in minimum incremental effect on water equity and productivity (on average 18.5 and 11.9 %, respectively). Furthermore, the values of performance measure decreased from wet water year to drought water year. Tape irrigation system was considered as the best choice at low quantities of WRF (<=0.4), however for higher values of WRF (>?=?0.6), sprinkler irrigation system was considered as the best choice for achieving higher values of water equity and productivity. Meanwhile, when equity and productivity were considered together for a specific method of deficit irrigation scheduling, under specified quantity of irrigation water, with increasing equity the water productivity reduction was negligible.     

黄河流域水资源利用效率测度与评价

通过采用数据包络分析法(data envelopment analysis，DEA)和Malmquist指数，对黄河流域68个地级行政单元的水资源利用效率进行测算。结果表明:2017年黄河流域水资源利用效率达到DEA有效的地级行政单元有26个、非DEA有效的地级行政单元有42个；通过对42个非DEA有效行政单元的投入冗余测算，发现由于规模效率不高造成的有27个、技术效率低下造成的有15个。2009—2017年，黄河流域水资源利用效率呈现先上升、后下降、波动大的特点，水资源利用效率整体有所提升，且技术水平是影响其关键因素。从流域来看，2009—2017年黄河流域水资源全要素生产率(total factor productivity，TFP)指数的综合平均值为0.957；其中，下游地区的水资源利用效率最高，TFP指数为0.977；上游和中游地区次之，TFP指数分别为0.958和0.948。     

Variable fuzzy assessment of water use efficiency and benefits in irrigation district

In order to scientifically and reasonably evaluate water use efficiency and benefits in irrigation districts, a variable fuzzy assessment model was established. The model can reasonably determine the relative membership degree and relative membership function of the sample indices in each index's standard interval, and obtain the evaluation level of the sample through the change of model parameters. According to the actual situation of the Beitun Irrigation District, which is located in Fuhai County, in Altay City, Xinjiang Uyghur Autonomous Region, five indices were selected as evaluation factors, including the canal water utilization coefficient, field water utilization coefficient, crop water productivity,effective irrigation rate in farmland, and water-saving irrigation area ratio. The water use efficiency and benefits in the Beitun Irrigation District in different years were evaluated with the model. The results showed that the comprehensive evaluation indices from 2006 to 2008 were all at the third level(medium efficiency), while the index in 2009 increased slightly, falling between the second level(relatively high efficiency) and third level, indicating an improvement in the water use efficiency and benefits in the Beitun Irrigation District, which in turn showed that the model was reliable and easy to use. This model can be used to assess the water use efficiency and benefits in similar irrigation districts.     

基于超效率DEA模型的宁夏工业水资源利用效率研究

提高水资源利用效率是解决水资源短缺问题的关键。利用超效率DEA模型和Malmquist指数法,选取工业耗水量、工业从业人数和工业固定资产净值为投入指标,工业总产值和废污水排放量为产出指标,对宁夏回族自治区2006-2016年的工业水资源利用效率从动态和静态两个角度进行了分析。结果表明:宁夏地区工业用水效率整体良好,技术效率是降低整个自治区工业用水效率的主要因素;银川市和石嘴山市近5年用水状况较为合理且全要素生产率增长较快,吴忠和中卫市劳动力冗余严重,固原市技术和规模方面都最为落后。此研究可为全区工业生产以及资源配置提供科学依据。     

Optimization of Irrigation Scheduling Using Soil Water Balance and Genetic Algorithms

In arid and semi-arid countries, the use of irrigation is essential to ensure agricultural production. Irrigation water use is expected to increase in the near future due to several factors such as the growing demand of food and biofuel under a probable climate change scenario. For this reason, the improvement of irrigation water use efficiency has been one of the main drivers of the upgrading process of irrigation systems in countries like Spain, where irrigation water use is around 70 % of its total water use. Pressurized networks have replaced the obsolete open-channel distribution systems and on farm irrigation systems have been also upgraded incorporating more efficient water emitters like drippers or sprinklers. Although pressurized networks have significant energy requirements, increasing operational costs. In these circumstances farmers may be unable to afford such expense if their production is devoted to low-value crops. Thus, in this work, a new approach of sustainable management of pressurized irrigation networks has been developed using multiobjective genetic algorithms. The model establishes the optimal sectoring operation during the irrigation season that maximize farmer’s profit and minimize energy cost at the pumping station whilst satisfying water demand of crops at hydrant level taking into account the soil water balance at farm scale. This methodology has been applied to a real irrigation network in Southern Spain. The results show that it is possible to reduce energy cost and improve water use efficiency simultaneously by a comprehensive irrigation management leading, in the studied case, to energy cost savings close to 15 % without significant reduction of crop yield.     

Using MODFLOW and GIS to Assess Changes in Groundwater Dynamics in Response to Water Saving Measures in Irrigation Districts of the Upper Yellow River Basin

The irrigation districts of the upper Yellow River basin are highly productive agricultural areas of North China. Due to the severe water scarcity, application of water-saving practices at both farm and district levels are required for sustainable agricultural development. An integrated methodology was developed adopting loose coupling of the groundwater flow model MODFLOW with ArcInfo Geographic Information System to assess the impacts of irrigation water-saving practices and groundwater abstraction foreseen for the year of 2020 on the groundwater dynamics of the Jiefangzha Irrigation System (JFIS) in Hetao Irrigation District, upper Yellow River basin. The model was calibrated and validated with datasets of years 2004 and 2005; the model efficiency EF was respectively 0.98 for calibration and 0.99 for validation. Results of the simulation of the groundwater dynamics of the study area show that water-saving practices referring to canal lining and upgrading hydraulic structures applied in 60% of the area, and upgraded farm irrigation technology in 50% of the area may consist of a reasonable solution. Their implementation would lead to reduce groundwater evaporation by 43 mm and the total diversions from the Yellow River by 208 mm, i.e. about 20% of present volumes diverted. Most of routines and strategies for model construction may also be used for other regions, especially for irrigation districts in the upper Yellow River basin.     

The Pros and Cons of Encouraging Shallow Groundwater Use through Controlled Drainage in a Salt-Impacted Irrigation Area

Encouraging shallow groundwater use through water table management or controlled drainage in irrigated areas can relief crop water stress under water shortage condition. But substituting fresh irrigation water with saline groundwater may speed up salinity buildup in the crop root zone, and consequently increase water use for salt leaching. With a proposed analytical model, this paper presents a case study demonstrating the effect of encouraging shallow groundwater use through controlled drainage on salt and water management in a semi-arid irrigation area in northwestern China. Based on the average rainfall condition, the model assumes that salt accumulates in the crop root zone due to irrigation and shallow groundwater use; till the average soil salinity reaches the crop tolerance level, leaching irrigation is performed and the drainage outlet is lowered to discharge the salt-laden leaching water. For the relatively salt tolerant crop–cotton in the study area, the predicted leaching cycle was as long as 751 days using the fresh water (with salinity of 0.5 g/L) irrigation only; it was shortened to 268 days when the water table depth was controlled at 2 m and 23% of the crop water requirement was contributed from the saline groundwater (with salinity of 4.43 g/L). The predicted leaching cycle was 140 days when the water table depth was controlled at 1.5 m and groundwater contribution was 41% of the crop water requirement; it was shortened to 119 days when the water table depth was controlled at 1.2 m and the groundwater contribution was 67% of the crop water requirements. So the benefit from encouraged shallow groundwater use through controlled drainage is obtained at the expense of shortened leaching cycle; but the shallow groundwater use by crops consists of a significant portion of crop water requirements, and the leaching cycle remains long enough to provide a time window for scheduled leaching in the off season of irrigation. Weighing the pros and cons of the encouraged shallow groundwater use may help plan irrigation and drainage practices to achieve higher water use efficiency in saline agricultural areas.     

Methodology for Detecting Critical Points in Pressurized Irrigation Networks with Multiple Water Supply Points

The modernization processes of hydraulic infrastructures from old open channels to pressurized networks have increased water use efficiency along with a dramatic increase of energy consumptions. The significant energy requirements associated with the increment of the energy tariffs for irrigation involve higher production costs for farmers. Therefore, strategies to reduce energy consumption in irrigation districts are strongly demanded. Methodologies based on sectoring and critical points control have been applied to branched networks with a single water supply point, obtaining significant energy savings. In this work, a new critical point control methodology for networks with multiple sources has been developed: the WEPCM algorithm, which uses the NSGA-II multi-objective evolutionary algorithm to find the lowest energy consumption operation rule of a set of pumping stations connected to an irrigation network that satisfies the pressure requirements, when the critical points are successively disabled. WECPM has been applied to a real irrigation district in Southern Spain. The obtained results were compared with those achieved by the WEBSOM algorithm, developed for sectoring multiple source networks. The control of critical points by the replacement of two pipes and the installation of four booster pumps provided annual energy savings of 36 % compared to the current network operation. Moreover, the control of critical points was more effective than sectoring, obtaining an additional annual energy saving of 10 %.     

Detecting Critical Points in On-Demand Irrigation Pressurized Networks – A New Methodology

In many pressurized irrigation water distribution networks, rising energy costs are having a significant impact on system performance, environmental impact and the profitability of agribusinesses and farms dependant on water supplies for irrigated production. In this study, a new methodology is proposed for analysing the location of critical control points (hydrants) to reduce energy consumption. The methodology is developed and applied using two irrigation districts located in Southern Spain (Fuente Palmera and El Villar). The new approaches provide a framework for comparing different energy saving strategies, including improved critical point management and network sectoring. The results show that potential energy savings of around 10% and 30% are possible in each district when the theoretical irrigation requirements are modeled. However these savings reduce to 5% and 12% when the local farmers’ practices of deficit irrigation are incorporated. These results are compared to those obtained for networks sectoring in the same irrigation networks in a previous work. The study confirms that that a sectoring approach works best for reducing the energy costs associated with meeting actual irrigation water demands in irrigation districts where energy consumption is a limiting factor on production.     

Quantifying the Vulnerability of Surface Water Environment in Humid Areas Base on DEA Method

Vulnerability of water environmental is defined as a measure of the degree of water pollution and its susceptibility and resilience under the influence of both human activities and natural causes. Analysis in this study indicates that water environment in a humid and intensive human activity area such as Southern China is more vulnerable to water quality than to water quantity. The vulnerability of water environment is the key element of water security in these regions. This study provided a new approach to quantify the vulnerability of surface water environment in humid areas through a case study in Southern China. Taking the pollution of water environment as an input–output process, the classic Data Envelopment Analysis method (DEA) which has often been used in the management science, was introduced to establish an evaluation model to access the vulnerability of surface water environment. The analysis results for the 7 water resources districts in the Pearl River Basin of China using the SEA method showed that majority of these water resources districts have abundant water resources, greater carrying capacity, and less vulnerable to shortage of water resources and contamination of water environment.     

Optimizing Deficit Irrigation Scheduling Under Shallow Groundwater Conditions in Lower Reaches of Amu Darya River Basin

Water demand for irrigated agriculture is increasing against limited availability of fresh water resources in the lower reaches of the Amu Darya River e.g., Khorezm region of Uzbekistan. Future scenarios predict that Khorezm region will receive fewer water supplies due to climate change, transboundary conflicts and hence farmers have to achieve their yield targets with less water. We conducted a study and used AquaCrop model to develop the optimum and deficit irrigation schedule under shallow groundwater conditions (1.0–1.2 m) in the study region. Cotton being a strategic crop in the region was used for simulations. Capillary rise substantially contributes to crop-water requirements and is the key characteristic of the regional soils. However, AquaCrop does not simulate capillary rise contribution, thereby HYDRUS-1D model was used in this study for the quantification of capillary rise contribution. Alongside optimal irrigation schedule for cotton, deficit strategies were also derived in two ways: proportional reduction from each irrigation event (scenario-A) throughout the growth period as well as reduced water supply at specific crop growth stages (scenario-B). For scenario-A, 20, 40, 50 and 60 % of optimal water was deducted from each irrigation quota whereas for scenario-B irrigation events were knocked out at different crop growth stages (stage 1(emergence), stage 2 (vegetative), stage 3 (flowering) and stage 4 (yield formation and ripening)). For scenario-A, 0, 14, 30 and 48 % of yield reduction was observed respectively. During stress at the late crop development stage, a reduced water supply of 12 % resulted in a yield increase of 8 %. Conversely, during stress at the earlier crop development stage, yield loss was 17–18 %. During water stress at the late ripening stage, no yield loss was observed. Results of this study provide guidelines for policy makers to adopt irrigation schedule depending upon availability of irrigation water.     

Temporal Variability of Water Footprint for Maize Production: The Case of Beijing from 1978 to 2008

The water footprint (WF) of crop production is a comprehensive indicator that can reflect water consumption types, quantities and environmental impacts during the crop growth period. This study assesses interannual variability of green, blue and grey WFs of maize production in Beijing from 1978 to 2008. Results indicate that: (1) The multi-year average WF of maize was 1,031 m³ ton^?1 which was 56 % green, 25 % blue, and 19 % grey; (2) the climate experienced a warm-dry period in Beijing during the period from 1978 to 2008, and this lead to the increase of crop water requirement and irrigation water requirement for maize with trends of 0.52 mm a^?1 and 2.86 mm a^?1, respectively; (3) under the combined effects of climate change and agricultural inputs, the total WF and green WF presented decreasing trends. The blue and grey WFs had clear increasing trends; (4) statistical analysis revealed that interannual variability of green and blue WFs were caused by both climatic factors (effective precipitation) and non-climatic (agricultural inputs) factors. The grey WF was mainly associated with non-climatic factors, such as chemical fertilizers consumption.     

长江经济带11省市水资源利用效率评价

最严格水资源管理制度的实现和水生态文明的建设,都依赖于水资源利用效率的提升,因此,掌握区域水资源利用效率非常必要。运用数据包络分析法,以长江经济带11省市的国内生产总值为产出指标,以固定资产投资总额、农业用水量、工业用水量、生活用水量、生态用水量、就业人口作为投入指标,对11省市2004年和2012年的水资源利用效率进行对比分析,并运用Malmquist指数法对2004~2012年间的水资源利用效率变化进行了分析。结果表明,长江经济带的整体水资源利用效率呈逐渐下滑趋势;其中,上海、浙江和四川水资源利用效率相对较高;制约水资源利用效率提高的主要因素是技术发展,因而加大技术革新、创新和技术应用是提升水资源利用效率的关键路径。     

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.     

Modeling the Effect of Cistern Size,Soil Type,and Irrigation Scheduling on Rainwater Harvesting as a Stormwater Control Measure

Urban stormwater runoff could have negative impacts on water resources and the environment. Rainwater Harvesting (RWH) can serve both as a stormwater control and water conservation measure. Cistern size and irrigation scheduling are two of the factors that directly impact the total runoff from a residential unit with a RWH system and the amount of potable water used for irrigation. The effectiveness of RWH was evaluated for four soil types; Sand, Sandy Loam, Loamy Sand, and Silty Clay, with a root zone of 15.2 cm using three irrigation scheduling methods (Evapotranspiration (ET)-based, soil moisture-based, and time-based), and five cistern sizes. Total runoff volumes and total supplemental potable water used were compared among the three irrigation scheduling systems and a control treatment without RWH. A model was developed to simulate the daily water balance for the treatments. Irrigation and runoff volumes were compared for the various scenarios. Silty clay soil resulted with 83 % more runoff than Sandy soil, while Sandy soil required on average 58 % more supplemental water than Silty Clay soil. On average, the 833 L cistern resulted with 41 % savings in water supply and 45 % reduction in total runoff. Results showed that the greatest volumes of runoff predicted were for the silty clay soil Control Treatment using a time-based irrigation scheduling method, while the least volumes calculated were for the sandy loam soil time-based irrigation scheduling treatment with 833 L cistern size. The greatest volumes of total supplemental water predicted were for sandy loam soil Control Treatment, while the least volumes were for silty clay soil ET-based irrigation scheduling treatment with 833 L cistern size. Regression equations were developed to allow for users to select a RWH cistern size based on the amount of water they want to save or runoff to reduce.     

Application of Integrated Hydrologic and River Basin Management Modeling for the Optimal Development of a Multi-Purpose Reservoir Project

Multi-purpose reservoir development have been always a big challenge for the management of water resources. This paper describes an integrated approach for investigating catchment hydrology in the development of a hydropower and a canal irrigation system based on model analyses. The investigation aims to adequately determine an optimal domestic and irrigation water resources allocation scheme based on an assessment of the reservoir water balance and capacity for hydropower. The soil and water assessment tool (SWAT) which characterizes basin hydrology and the water management and planning model MODSIM which provides a decision support system for water allocation optimization, were used in this study. The integrated approach was applied to Prek Te River basin in Cambodia. The water demand aspect was examined based on domestic water use, irrigation water, environmental flow, and water losses. An operational rule curve was developed for hydropower operation with respect to a power potential of 13 MW. Hydrologic modeling revealed 90 % dependable water of about 2.7 m³/s during the dry season and 214.3 m³/s during the wet season, indicative of a wet-season dependent reservoir for storage. Results from the 26-years simulation period also showed that diversions for domestic water and irrigation water supply were 92.3 % dependable for a 13 MW capacity hydropower development. The integrated approach was shown to be a valuable decision support tool for water resources management with the determination of an optimum policy for multi-purpose reservoir operation based on available basin water supply.