Using satellite remote sensing to assess irrigation performance in Water User Associations in the Lower Gediz Basin, Turkey

The aim of this research was to assess the irrigation performance of the Salihli Right Bank, Salihli Left Bank, Ahmetli, Gokkaya, Turgutlu, Mesir, Sarikiz, Gediz, Menemen Right Bank and Menemen Left Bank Water User Associations (WUAs) in the Lower Gediz Basin in western Turkey, using remote sensing techniques. To reach this aim the performance of the irrigation system for the 2004 irrigation season was determined according to five indicators, namely overall consumed ratio (e_p), relative water supply (RWS), depleted fraction (DF), crop water deficit (CWD) and relative evapotranspiration (RET). Potential and actual evapotranspiration parameters used in determining these indicators were estimated according to the Surface Energy Balance Algorithm for Land (SEBAL) method using NOAA-16 satellite images.Seasonal averages of these indicators ranged from 0.59 to 2.26 for e_p, 0.47-1.66 for RWS, 0.43-1.31 for DF, 180.5-269.5 mm month⁻¹ for CWD, and 0.61-0.74 for RET. According to the seasonal average values of all the performance indicators, the irrigation performance of all WUAs was usually poor. The performance indicators showed that less irrigation water was supplied to WUAs than was needed. It was concluded that proximity to the source could be an advantage in obtaining water, and that when water was insufficient, groundwater in the crop root area could be used.     

Assessment of alternative water management options for irrigated agriculture

A simulation study on alternative water management strategies was carried out for Sirsa Irrigation Circle in Haryana, covering an area of about 4800 km². Results showed that crop evapotranspiration and soil salinity development under reduction in canal water supply and increase in groundwater use, are largely influenced by the amount and distribution of rainfall. Reduction in canal water supply by 25% during the rainy season is unlikely to have any adverse effect on the salinity development in the study area. Reduction in crop evapotranspiration due to decreased canal water supply can partly be compensated by the increase in groundwater use. Leaching of salts due to monsoon rains in the study area shows that groundwater of even relatively poor quality can be used for irrigation without excessive long-term build up of soil salinity under deep groundwater depth conditions. However, increased groundwater extraction without associated actions will not be very effective to solve the problem of rising groundwater levels.     

Integrating remote sensing and a process-based hydrological model to evaluate water use and productivity in a south Indian catchment

The combined use of remote sensing and a distributed hydrological model have demonstrated the improved understanding of the entire water balance in an area where data are scarcely available. Water use and crop water productivity were assessed in the Upper Bhima catchment in southern India using an innovative integration of remotely sensed evapotranspiration and a process-based hydrological model. The remote sensing based Surface Energy Balance Algorithm for Land (SEBAL) was used to derive an 8 month time series of observed actual evapotranspiration from October 2004 to May 2005. This dataset was then used in the calibration of the Soil and Water Assessment Tool (SWAT). This hydrological model was calibrated by changing 34 parameters to minimize the difference between simulated and observed actual evapotranspiration. The calibration efficiency was assessed with four different performance indicators. The calibrated model was used to derive a monthly basin water balance and to assess crop water productivity and crop water use for the irrigation year 2004-2005. It was found that evapotranspiration is the largest water loss in the catchment and total evaporative depletion was 38,172 Mm³ (835 mm). Of the total evaporative depletion 42% can be considered as non-beneficial and could be diverted to other beneficial utilization. Simulated crop water productivities for sugarcane, sorghum and winter wheat are relatively high at 2.9 kg/m³, 1.3 kg/m³ and 1.3 kg/m³, respectively. The frequency distributions of crop water productivity are characterised by low coefficient of variation, yielding limited scope for improvement in the agricultural areas under the current cropping systems. Further improvements in water productivity may however be achieved by shifting the crop base from sugarcane to a dual crop and introducing a fallow period from March to May or by converting non-productive rangelands to bio fuel production or other agricultural land uses.     

Earth Observation products for operational irrigation management in the context of the PLEIADeS project

Controlled and efficient agricultural irrigation management is required to avoid negative effects of the increasing world water scarcity and therefore to assure a sustainable production. Within this context, the project ‘Participatory multi-Level EO-assisted tools for Irrigation water management and Agricultural Decision-Support’ (PLEIADeS: http://www.pleiades.es) addressed the efficient and sustainable use of water for food production in water-scarce environments. The project aimed at improving the performance of irrigation schemes by means of a range of measures, made possible through wide space-time coverage of Earth Observation (E.O.) data and interactive networking capabilities of Information and Communication Technologies (ICT). Project partners, represented by a set of pilot case-studies, included a broad range of conditions characteristic for the European, Southern Mediterranean and American regions. Algorithms for a number of basic products for the estimation of Irrigation Water Requirements (IWR) have been defined in an operational framework. In this study a review of application of these algorithms, applied and validated within different case-studies during the project, is presented.     

Didactic tools for supporting participatory water management in collective irrigation schemes

In many irrigation schemes, Water Users Associations (WUAs) acquired the responsibility for water management after withdrawal of the state. Based on the success of some indigenous irrigation schemes, it was assumed that farmers could easily become managers. As decision-making was the exclusive terrain of the governmental agencies that ran the schemes, farmers never gained the necessary experience with water management. Therefore, training of farmers and WUAs on the principles and processes of water management is essential. This paper demonstrates a practical example of training material on water management that incorporates research results on the process of Irrigation Management Transfer and resulting farmers’ water management for the case of the Office du Niger irrigation scheme. The results of the paper explain how input from research was used in the four steps of the construction of training material. These steps are (1) setting the training agenda, (2) selecting and adapting information to be featured, (3) targeting the audience and (4) designing the actual training material. A first validation of the approach and examples of the actual training material were obtained in a workshop uniting all stakeholders.     

Long-term water balances in La Violada Irrigation District (Spain): II. Analysis of irrigation performance

The analysis of long-term irrigation performance series is a valuable tool to improve irrigation management and efficiency. This work focuses in the assessment of irrigation performance indices along years 1995-2008, and the cause-effect relationships with irrigation modernization works taking place in the 4000 ha surface-irrigated La Violada Irrigation District (VID). Irrigation management was poor, as shown by the low mean seasonal irrigation consumptive use coefficient (ICUC = 51%) and the high relative water deficit (RWD = 20%) and drainage fraction (DRF = 54%). April had the poorest irrigation performance because corn (with low water demand in this month) was irrigated to promote its emergence, whereas winter grains (with high water demands in this month) were not fully irrigated in water-scarce years. Corn, highly sensitive to water stress, was the crop with best irrigation performance because it was preferentially irrigated to minimize yield losses. The construction of a new elevated canal that decreased seepage and drainage fractions, the entrance in operation of six internal reservoirs that would increase irrigation scheduling flexibility, and the on-going transformation from surface to sprinkler irrigation systems are critical changes in VID that should lead to improved ICUC, lower RWD and lower DRF. The implications of these modernization works on the conservation of water quantity and quality within and outside VID is further discussed.     

Operational aspects of satellite-based energy balance models for irrigated crops in the semi-arid U.S.

SEBAL and METRIC remote sensing energy-balance based evapotranspiration (ET) models have been applied in the western United States. ET predicted by the models was compared to lysimeter-measured ET in agricultural settings. The ET comparison studies showed that the ET estimated by the remote sensing models corresponded well with lysimeter-measured ET for agricultural crops in the semi-arid climates. Sensitivity analyses on impacts of atmospheric correction for surface temperature and albedo showed that the internal calibration procedures incorporated in the models helped compensate for errors in temperature and albedo estimation. A repeatability test by two totally independent model applications using different images, operators and weather datasets showed that seasonal estimations by the models have high repeatability (i.e. stable results over ranges in satellite image timing, operator preferences and weather datasets). These results imply that the SEBAL/METRIC remote sensing models have a high potential for successful ET estimation in the semi-arid United States.     

On-farm labour allocation and irrigation water use: case studies among smallholder systems in arid regions

On-farm measurements and observations of water flow, water costs and irrigation labour inputs at the individual parcel level were made in case studies of smallholder irrigation systems in sub-Saharan Africa and south-eastern Arabia. The systems, in which the water source supplied either single or multiple users, were analysed to address the fundamental issues of labour allocation for on-farm water management as this has important consequences for the success of such systems. Results show that the costs associated with accessing water influenced labour input, because when they were low the farmers tended to increase the irrigation rate and reduce the amount of time they spent distributing the water within their parcels. Conversely when water costs were high, lower flow rates and more time spent in water distribution were observed, and this resulted in more uniform irrigation and higher irrigation efficiency. Also, opportunities and demands for farmers to use their labour for activities other than irrigation can lead them to modify operational or physical aspects of the system so that they can reduce the time they spend distributing water within the parcels, particularly when the water is relatively cheap. Awareness and better understanding of how farmers may allocate their labour for water management will lead to more effective planning, design and management of smallholder irrigation systems.     

Management trends and responses to water scarcity in an irrigation scheme of Southern Spain

Improvement of irrigation management in areas subjected to periods of water scarcity requires good knowledge of system performance over long time periods. We have conducted a study aimed at characterizing the behaviour of an irrigated area encompassing over 7000 ha in Southern Spain, since its inception in 1991. Detailed cropping pattern and plot water use records allowed the assessment of irrigation scheme performance using a simulation model that computed maximum irrigation requirements for every plot during the first 15 years of system operations. The ratio of irrigation water used to maximum irrigation requirements (Annual Relative Irrigation Supply, ARIS) was well below 1 and oscillated around 0.6 in the 12 years that there were no water supply restrictions in the district. The ARIS values varied among crops, however, from values between 0.2 and 0.3 for sunflower and wheat, to values approaching 1 for cotton and sugar beet. Farmer interviews revealed some of the causes for the low irrigation water usage which were mainly associated with the attempt to balance profitability and stability, and with the lack of incentives to achieve maximum yields in crops subsidized by the Common Agricultural Policy (CAP) of the European Union. The response to water scarcity was also documented through interviews and demonstrated that the change in crop choice is the primary reaction to an anticipated constraint in water supply. Water productivity (value of production divided by the volume of irrigation water delivered; WP) in the district was moderate and highly variable (around 2€ m⁻³) and did not increase with time. Irrigation water productivity (increase in production value due to irrigation divided by irrigation water delivered) was much lower (0.65€ m⁻³) and also, it did not increase with time. The lack of improvement in WP, the low irrigation water usage, and the changes in cropping patterns over the first 15 years of operation indicate that performance trends in irrigated agriculture are determined by a complex mix of technical, economic, and socio-cultural factors, as those that characterized the behaviour of the Genil-Cabra irrigation scheme.     

SEBAL for detecting spatial variation of water productivity and scope for improvement in eight irrigated wheat systems

A methodology has been developed to quantify spatial variation of crop yield, evapotranspiration (ET) and water productivity (WP_ET) using the SEBAL algorithm and high and low resolution satellite images. SEBAL-based ET estimates were validated over an irrigated, wheat dominated area in the Yaqui Valley, Mexico and proved to be accurate (8.8% difference for 110 days). Estimated average wheat yields in Yaqui Valley of 5.5 t ha⁻¹ were well within the range of measured yields reported in the literature. Measured wheat yields in 24 farmers’ fields in Sirsa district, India, were 0.4 t ha⁻¹ higher than SEBAL estimated wheat yields. Area average WP_ET in the Yaqui Valley was 1.37 kg m⁻³ and could be considered to be high as compared to other irrigated systems around the world where the same methodology was applied. A higher average WP_ET was found in Egypt's Nile Delta (1.52 kg m⁻³), Kings County (CA), USA (1.44 kg m⁻³) and in Oldambt, The Netherlands (1.39 kg m⁻³). The spatial variability of WP_ET within low productivity systems (CV = 0.33) is higher than in high productivity systems (CV = 0.05) because water supply in the former case is uncertain and farming conditions are sub-optimal. The high CV found in areas with low WP_ET indicates that there is considerable scope for improvement. The average scope for improvement in eight systems was 14%, indicating that 14% ET reduction can be achieved while maintaining the same yield. It is concluded that the proposed methodology is accurate and that better knowledge of the spatial variation of WP_ET provides valuable information for achieving local water conservation practices in irrigated wheat.     

Estimation of water consumption and crop water productivity of winter wheat in North China Plain using remote sensing technology

The North China Plain (NCP) is one of the most water stressed areas in the world. The water consumption of winter wheat accounts for more than 50% of the total water consumption in this region. An accurate estimate of the evapotranspiration (ET) and crop water productivity (CWP) at regional scale is therefore key to the practice of water-saving agriculture in NCP. In this research, the ET and CWP of winter wheat in 83 counties during October 2003 to June 2004 in NCP were estimated using the remote sensing data. The daily ET was calculated using SEBAL model with NOAA remote sensing data in 17 non-cloud days whereas the reference daily crop ET was estimated using meteorological data based on Hargreaves approach. The daily ET and the total ET over the entire growing season of winter wheat were obtained using crop coefficient interpolation approach. The calculated average and maximum water consumption of winter wheat in these 83 counties were 424 and 475 mm, respectively. The calculated daily ET from SEBAL model showed good match with the observed data collected in a Lysimeter. The error of ET estimation over the entire growing stage of winter wheat was approximately 4.3%. The highest CWP across this region was 1.67 kg m⁻³, and the lowest was less than 0.5 kg m⁻³. We observed a close linear relationship between CWP and yield. We also observed that the continuing increase of ET leads to a peaking and subsequent decline of CWP, which suggests that the higher water consumption does not necessarily lead to a higher yield.     

Volumetric irrigation water pricing considerations

Volumetric water pricing is a popular topic within donor agencies for irrigation project modernization and sustainability. Implementation of an effective pricing program is quite complex and requires consideration of physical modernization, fee structure, enforcement procedures, and the level of water delivery service. Variations of volumetric water pricing and allocation are discussed.     

Soil water content and water balance in rainfed fields in Northeast Thailand

Northeast Thailand has a semi-humid tropical climate which is characterized by dry and rainy seasons. In order to stabilize crop production, it may be necessary to develop new water resources, such as soil moisture and groundwater, instead of rainfed resources. This is because rainfed agriculture has already been unsuccessfully tried in many areas of this region. In this study, we investigate the soil water content in rainfed fields in Khon Kaen in Northeast Thailand, where rice and sugarcane were planted, over a 1-year period that contained both dry and rainy seasons, and estimate the actual evapotranspiration (ET_a) using micrometeorological data. In addition, we assess the water balance from the results of the soil water content investigation and the actual evapotranspiration. Although the soil water content at depths above 0.6 m in both the lower and the sloping fields gradually decreased during the dry season, the soil water content at a depth of 1.0 m was under almost constant wet conditions. Two-dimensional profiles of the soil water content demonstrated that at the end of the dry season, the soil layers below a depth of 0.4 m showed a soil water content of more than 0.10-0.15 m³ m⁻³, thus suggesting that water was supplied to the sugarcane from those layers. The range in ET_a rates was almost the same as that in the previous study. The average ET_a rates were 3.7 mm d⁻¹ for the lower field and 4.2 mm d⁻¹ for the sloping field. In the dry season, an upward water flow of 373 mm (equivalent to a flux of 1.9 mm d⁻¹) was estimated from outside the profile. The source of this upward water flow was the sandy clay (SC) layer below a depth of 1 m. It was this soil water supply from the SC layer that allowed the sugarcane to grow without irrigation.     

Role of irrigation and mulch on yield, evapotranspiration rate and water use pattern of tomato (Lycopersicon esculentum L.)

Irrigation management strategy invites the quantification of crop response to irrigation frequencies. Conventionally, mulches increase the yield and water use efficiency (WUE) to a great extent by augmenting the water status in the root zone profile. A field study was carried out during the winter season (November-March) of 2003-2004 and 2004-2005 at the Central Research Farm of Bidhan Chandra Krishi Viswavidyalaya (Latitude 22°58′N, Longitude 88°31′E and altitude 9.75 m amsl), Gayeshpur, India, to evaluate the effect of irrigation frequencies and mulches on evapotranspiration rate from tomato crop field as well as leaf area index (LAI), fruit yield and WUE of the crop. The experiment was laid out in a split-plot design where three irrigation treatments {rainfed (RF); CPE₅₀ and CPE₂₅ where irrigation was given at 50 and 25 mm of cumulative pan evaporation (CPE)} were kept in the main plots and the subplots contained four mulch managements {no mulch (NM), rice straw mulch (RSM), white polyethylene mulch (WPM) and black polyethylene mulch (BPM)}. Under CPE₂₅, tomato crop recorded significantly higher leaf area index (LAI) over CPE₅₀ and rainfed condition. LAI value under BPM was 9-30% more over other mulches. Maximum variation of LAI among different treatments was recorded at 60 days after transplanting (DAT). Fruit yield under CPE₂₅ was 39.4 Mg ha⁻¹; a reduction of 7 and 30% has been obtained under CPE₅₀ and RF condition. The use of mulch increased 23-57% yield in comparison to NM condition. Actual evapotranspiration rate (ET_R) was 1.82 mm day⁻¹ under CPE₂₅ and declined by 15 and 31% under CPE₅₀ and RF condition, respectively. The variation of ET_R among different mulches became more prominent under maximum water stressed (RF) condition, whereas the variation was negligible under CPE₂₅ frequency. Irrespective of mulching WUE was highest under moderately wet (CPE₅₀) soil environment. Among different mulches, BPM was responsible for attaining the highest WUE value (25.1 kg m⁻³), which declined by 22, 21 and 39% under WPM, RSM and NM, respectively.     

Farmer participation in irrigation management: The case of Doroodzan Dam Irrigation Network, Iran

The importance of farmer participation in system design and management has been emphasized in previous studies. The purpose of this study was to identify the factors affecting farmer participation in irrigation management using survey research. The study was conducted in Doroodzan Dam Irrigation Network in Fars province, Iran. Multistage stratified random sampling was used to collect data from 270 farmers as the research sample. Results reveal that farmers’ attitudes toward participation in irrigation management, attitudes toward personnel of the State Water Authority and the Agricultural Extension Service Centers (AESCs), family size, the problem perception, dependence on the dam for water, and educational background have influenced their participation in irrigation management. By contrast, contact with information sources, animal units, sociability, age and agricultural experience did not affect farmers’ participation. Moreover, based on farmers’ perspectives, unequal water distribution among farms, dissatisfaction with Water Authority operators and high water fees and charges were the main problems and obstacles toward farmer participation in irrigation management.     

基于陆面能量平衡方程的遥感模型

介绍了卫星遥感反演水文气象模式所需的一些基本地面参数,进而得到整个流域尺度上的ET的方法,特别是基于陆面能量平衡方程的SEBAL模型的原理及工作流程,指出了模型的优点和不足,并研究探讨了利用SEBAL模型在海河流域水资源管理中的应用。     

Field water supply:yield relationships of grain sorghum grown in three USA Southern Great Plains soils

Field water supply (FWS) combines the three sources of water used by a crop for evapotranspiration (ET), and consists of available soil water at planting (ASWP), rainfall, and irrigation. Examining the grain yield and FWS relationship (Y_g:FWS) may provide insight into the reported variability in crop water production functions such as water productivity (WP) and irrigation water productivity (IWP). Since water is most productive when entirely consumed in ET, diversion of FWS into non-ET losses such as drainage and excessive soil water evaporation results in declines in WP and IWP. The objective of this experiment was to examine the Y_g:FWS and Y_g:ET relationships of grain sorghum grown under a range of irrigation treatments (0, 25, 50, and 100% replacement of ET), beginning soil water contents, evaporative demands, in the Amarillo, Pullman, and Ulysses soils of the Great Plains. The purpose was to determine the amount of FWS beyond which declines in WP and IWP began to occur due to non-ET losses as indicated by a change in the slope and intercept of the Y_g:FWS and Y_g:ET relationships. Large amounts of non-ET irrigation application losses occurred in the finer-textured soils in the T-100 irrigation treatment. In both years, the T-100 irrigation application amounts and ASWP resulted in a FWS ranging from 750 to 870 mm which exceeded the maximum ET requirement of 530-630 mm and which reduced WP and IWP. Piecewise regression analysis of the Y_g:FWS and Y_g:ET relationships for the crops in the Pullman and Ulysses soils identified the knot point, or change in slope and intercept, in the FWS where both WP and IWP tended to be optimized. This was about 500 mm in both soils, and involved the utilization of about 250 mm in ASWP, irrigation applications averaging about 250 mm, and about 60-130 mm remaining in the soil at harvest. For the coarser-textured Amarillo soil, the yield response to increasing FWS was linear, because non-ET application losses such as drainage gradually increased with the irrigation application amount. The linear Y_g response in the sandy Amarillo soil and the piecewise Y_g responses in the clay and silt loams of the Pullman and Ulysses soils to FWS also reflected the difference in water-holding capacities of the soils that affected the amount of available water as irrigation increased. Irrigating without considering FWS resulted in non-ET irrigation application losses and declines in WP and IWP.     

Evaluation on the irrigation and fertilization management practices under the application of treated sewage water in Beijing, China

Irrigation and fertilization management practices play important roles in crop production. In this paper, the Root Zone Water Quality Model (RZWQM) was used to evaluate the irrigation and fertilization management practices for a winter wheat–summer corn double cropping system in Beijing, China under the irrigation with treated sewage water (TSW). A carefully designed experiment was carried out at an experimental station in Beijing area from 2001 to 2003 with four irrigation treatments. The hydrologic, nitrogen and crop growth components of RZWQM were calibrated by using the dataset of one treatment. The datasets of other three treatments were used to validate the model performance. Most predicted soil water contents were within ±1 standard deviation (S.D.) of the measured data. The relative errors (RE) of grain yield predictions were within the range of −26.8% to 18.5%, whereas the REs of biomass predictions were between −38% and 14%. The grain nitrogen (N) uptake and biomass N uptake were predicted with the RE values ranging from −13.9% to 14.7%, and from −11.1% to 29.8%, respectively. These results showed that the model was able to simulate the double cropping system variables under different irrigation and fertilization conditions with reasonable accuracy. Application of RZWQM in the growing season of 2001–2002 indicated that the best irrigation management practice was no irrigation for summer corn, three 83 mm irrigations each for pre-sowing, jointing and heading stages of winter wheat, respectively. And the best nitrogen application management practice was 120 kg N ha⁻¹ for summer corn and 110 kg N ha⁻¹ for winter wheat, respectively, under the irrigation with TSW. We also obtained the alternative irrigation management practices for the hydrologic years of 75%, 50% and 25%, respectively, in Beijing area under the conditions of irrigation with TSW and the optimal nitrogen application.     

Towards using a thermal infrared index combined with water balance modelling to monitor sugarcane irrigation in a tropical environment

In humid regions, the timing and quantity of a complementary irrigation regime is challenging because of the irregularity of rainfalls events. In this study, we tested the use of a thermal infrared derived empirical crop water stress index (CWSI_e) as an in situ measurement of the water status of sugarcane, to better monitor the irrigation scheduling. To do this, we set up a 2-year experiment in Reunion Island, on a trial with plots under different water conditions (rainfed and irrigated). Crop surface temperature was measured daily with infrared radiometers (Apogee Instruments) installed above the canopy, and soil moisture and drainage measurements were used to derive the ratio between actual and maximum evapotranspiration (AET/MET) values that were then averaged on “hydrically homogeneous” time periods (between 7 and 25 days). Only the thermal data acquired on clear days and 1 h after noon in 2007 were used to define the empirical lower and upper baselines required for the calculation of empirical CWSI. The data set acquired in 2008 was used to test the robustness of the method as we used the upper and lower baselines defined in 2007 to calculate CWSI_e. The linear regression between AET/MET and (1 − CWSI_e) averaged on the same periods (values ranging between 0.4 and 1) showed a significant correlation for both experimental years (global R² = 0.75 and RMSE = 0.12). This result indicates the effectiveness of the CWSI_e to measure the water status of the sugarcane crop, even in humid conditions with a vapor pressure deficit (VPD) between 0.5 and 2.1. We conclude the study by discussing the complementarity of this remote water stress index (CWSI_e) with OSIRI water balance modelling tool currently used in Reunion Island for monitoring sugarcane crop irrigation.     

Agricultural and environmental changes after irrigation management transfer in the Develi Basin,Turkey

Develi Basin is a semi-arid basin in central Turkey where water sustains both irrigated agriculture and an internationally important wetland, the Sultan Marshes. Agricultural and environmental changes in the Develi Basin have occurred since irrigation management was transferred in 1994 from a state authority (DSI) to irrigation associations (Kovalı and Ağcaaşar IAs). In this paper we evaluate the practices of the IAs using extensive data from interviews with farmers and IA officials, as well as data from reports prepared by DSI and the IAs, using comparisons with case studies reported in the scientific literature. Irrigated areas and surface water use in the Develi Basin showed significant fluctuations from 1995 to 2003. The area allocated to high water-consuming plants increased. Maintenance activities became dependent on fee collection rates. Quality of the irrigation water did not changed significantly. Ground-water levels, flow rates from springs, and water levels in the Sultan Marshes all dropped. Overall analyses indicate that the water requirements of the Sultan Marshes have not been met, while water use for irrigation has been effective but not efficient. To reconcile agricultural and wetland water requirements, a basin-wide approach in water planning is recommended. Amounts of water to be allocated to the IAs and wetlands need to be clearly defined. DSI has to monitor canal maintenance by the IAs more closely, and IAs need to be given more responsibilities for future rehabilitation of the canals. Realistic water pricing, increased reliability of irrigation scheduling, higher on-farm irrigation efficiency, and in the long-term, modernization of the irrigation system need to be considered.