Your search found 20 records
1 Rana, G.; Mastrorilli, M.; Albrizio, R. (Eds.) 2007. WEMED Workshop: how to advance the knowledge on water use efficiency in the Mediterranean region? Bari, Italy: International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM) 136p. (Series A, Mediterranean Seminars 72)
Water use efficiency ; Indicators ; Supplemental irrigation ; Soil water balance ; Crop production ; Environmental effects ; Climate change ; Water deficit ; Case studies ; Constraints ; Evapotranspiration ; Models ; Water conservation ; Irrigation scheduling ; Maize ; Wheat ; Economic evaluation ; Water user associations / Mediterranean Countries / Lebanon / Morocco
(Location: IWMI HQ Call no: 631.7.2 GG20 RAN Record No: H041294)
2 Rana, G.; Katerji, N. 2007. Crop evapotranspiration: methodology and application in Mediterranean region. In Rana, G.; Mastrorilli, M.; Albrizio, R. (Eds.). WEMED workshop: how to advance the knowledge on water use efficiency in the Mediterranean region?. Bari, Italy: International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM) pp.71-81.
Evapotranspiration ; Measurement ; Estimation ; Models ; Soil water balance / Mediterranean countires
(Location: IWMI HQ Call no: 631.7.2 GG20 RAN Record No: H041299)
3 Idowu, O. A.; Lorentz, S. A.; Annandale, J. G.; Aken, M.; McCartney, Matthew; Thornton-Dibb, S. L. C.; Westhuizen, A. 2010. Comparative assessment of widespread irrigation with low quality mine-water in undisturbed and rehabilitated mine-lands in the upper Olifants using the ACRU2000 model. Water SA, 36(5):543-552.
Water quality ; Salinity ; Simulation models ; Wastewater irrigation ; Coal mined land ; Soil water balance ; Reservoirs / South Africa / Upper Olifants River Basin / Tweefontein Reservoir
(Location: IWMI HQ Call no: e-copy only Record No: H043306)
http://www.ajol.info/index.php/wsa/article/viewFile/61988/50039
https://vlibrary.iwmi.org/pdf/H043306.pdf
https://vlibrary.iwmi.org/pdf/H043306.pdf
(0.81 MB) (833KB)
The ACRU agrohydrological model, in the form of ACRU2000 and its salinity module, ACRUSalinity, was employed in catchment-scale assessment of widespread irrigation with low quality mine-water in undisturbed (un-mined) and rehabilitated soils in the Upper Olifants basin of South Africa. The study area comprised a small catchment of 4.7 km2 located in a coal-mine environment, known as the Tweefontein Pan catchment. The catchment drained to a surface reservoir (Tweefontein Reservoir) of maximum capacity and surface area 4 000 Ml and 1.5 km2, respectively. The catchment was instrumented to measure hydrodynamic responses and simulated as a hydrological system. Consideration was given to runoff, groundwater storage, evapotranspiration, baseflow, interception, irrigation water supply and rainfall, thereby accounting for all the dominant hydrological components of the system. Three scenarios were simulated using the available records for 5 years (1999 to 2004). The first was a baseline scenario representing the prevailing condition in the study area and the other 2 scenarios represented widespread irrigation with the mine-water on undisturbed and rehabilitated soils. In simulating the widespread irrigation on rehabilitated soils, a distinction was made between a rehabilitated irrigated area before and after the re-establishment of the equilibrium water table. Comparison of the results from the simulated scenarios indicated that a greater undisturbed area (max of 160 ha) than rehabilitated area (max of 120 ha) could be irrigated with mine-water from the Tweefontein Reservoir. Irrigation on rehabilitated soils depleted the water in the reservoir more rapidly than irrigation on undisturbed soils, due to lower runoff and higher ingress to groundwater in rehabilitated areas.
4 Kinzelbach, W.; Aeschbach, W.; Alberich, C.; Goni, I. B.; Beyerle, U.; Brunner, P.; Chiang, W.-H.; Rueedi, J.; Zoellmann, K. 2002. A Survey of Methods for Groundwater Recharge in Arid and Semi-arid regions. Nairobi, Kenya: UNEP. 104p. (Early Warning and Assessment Report Series, UNEP/DEWA/RS.02-2)
Groundwater recharge ; Estimation ; Methods ; Surveys ; Soil water balance ; Remote sensing ; Mathematical models
(Location: IWMI HQ Call no: 553.79 G000 KIN Record No: H043912)
(5.77 MB) (5.76MB)
The rate of recharge is the single most important factor in the analysis and management of groundwater resources in arid and semi-arid regions. At the same time, it is also the most difficult quantity to determine. This document, which is the result of a course held in Niamey, Niger, in 2000, presents an overview of all the methods identified to date for estimating groundwater recharge, including an assessment of the accuracy and suitability of each. It then looks in more depth at a selection of methods best suited to arid and semiarid environments. Among these are the chloride method, the CFC and Tritium tracer methods, and the radiocarbon method. Excel spreadsheets and programmes are provided for calculating soil water balances, conducting geochemical analyses, dating environmental tracer concentrations, and building comprehensive groundwater flow and transport models. The key to the successful estimation of groundwater recharge lies in the utilisation of a variety of independent methods. Every method has its strengths and weaknesses, but combined they become much stronger. By bringing together environmental tracers, modern measurement techniques, automatic monitoring equipment, DGPS and remote sensing in a comprehensive groundwater model, the study of the hydrology of arid and semi-arid environments can enter a new era.
5 De Silva, C. S.; Weatherhead, E. K. 1997. Optimising the dimensions of agrowells in hard-rock aquifers in Sri Lanka. Agricultural Water Management, 33:117-126.
Wells ; Aquifers ; Irrigated farming ; Soil water balance ; Recharge ; Groundwater ; Models ; Case studies / Sri Lanka / North western province
(Location: IWMI HQ Call no: e-copy only Record No: H044308)
(0.51 MB)
A case study was conducted into the use of large diameter wells (agrowells) for supplementary irrigation from the hard-rock aquifer in the North-Western province of Sri Lanka. Two existing models, a radial groundwater How model and a soil water balance, were used together to represent the agrowell irrigation system. A technique is described to optimise new agrowell systems by deciding the optimum well radii for given aquifer characteristics and well spacing, or to optimize existing agrowell systems by deciding the sustainable irrigable command areas.
6 Tesema, M.; Schmitter, Petra; Nakawuka, Prossie; Tilahun, S. A.; Steenhuis, T.; Langan, Simon. 2016. Evaluating irrigation technologies to improve crop and water productivity of onion in Dangishta watershed during the dry monsoon phase. Paper presented at the International Conference of the Advancement of Science and Technology, Bahir Dar, Ethiopia, 17-18 July 2016. 10p.
Crop production ; Crop management ; Water productivity ; Water use efficiency ; Water conservation ; Water management ; Onions ; Monsoon climate ; Dry season ; Watershed services ; Wet cultivation ; Soil moisture ; Soil water balance ; Rhizosphere ; Rain ; Agriculture ; Fertilizer application / Ethiopia / Dangishta Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H047635)
(611 KB)
7 Mainuddin, M.; Kirby, M.; Chowdhury, R. A. R.; Shah-Newaz, S. M. 2015. Spatial and temporal variations of, and the impact of climate change on, the dry season crop irrigation requirements in Bangladesh. Irrigation Science, 33(2):107-120. [doi: https://doi.org/10.1007/s00271-014-0451-3]
Irrigated farming ; Dry season ; Crops ; Irrigation requirements ; Climate change ; Evapotranspiration ; Soil water balance ; Groundwater ; Simulation models ; Rice ; Planting date ; Rain / Bangladesh
(Location: IWMI HQ Call no: e-copy only Record No: H047690)
(2.98 MB)
Sustaining irrigation is vital for ensuring future food security in the face of population growth and a changing climate in Bangladesh. In this study, a daily soil water balance simulation model was used to estimate the net irrigation requirements of nine crops including Boro rice for the historical period of 1985–2010 and for future climate scenarios of 2030 and 2050 dry and average conditions using the A1B emission scenario. The average net irrigation requirement of Boro rice, the main crop, is 676 mm with temporally averaged spatial variation of 644–779 mm and spatially averaged temporal variation of 570–755 mm for base case planting on clay loam soil. The variations are due to the variation in crop evapotranspiration and rainfall during the cropping period. Changing planting or sowing date affects the net irrigation requirement which for Boro rice is lower in early (October–November) or late planting (January–February). The net irrigation requirement of Boro rice is about twice that required by wheat, maize, potato, tomato and sunflower, three times that of pulses and 5–6 times that required by oilseeds. The impact of climate change on irrigation requirements of Boro rice is small. The average irrigation requirement is projected to increase by a maximum of 3 % for the 2050 dry scenario. For other crops this is projected to increase by 1–5 % depending on the crop and the time of sowing/planting.
8 Bharati, Luna; Bhattarai, Utsav; Khadka, Ambika; Gurung, Pabitra; Neumann, L. E.; Penton, D. J.; Dhaubanjar, Sanita; Nepal, S. 2019. From the mountains to the plains: impact of climate change on water resources in the Koshi River Basin. Colombo, Sri Lanka: International Water Management Institute (IWMI) 49p. (IWMI Working Paper 187) [doi: https://doi.org/10.5337/2019.205]
Climate change ; Climatic data ; Water resources ; Water balance ; Water yield ; Water availability ; Mountains ; Plains ; River basin management ; Soil analysis ; Soil water balance ; Calibration ; Spatial distribution ; Hydropower ; Precipitation ; Evapotranspiration ; Temperature ; Rainfall ; Monsoon climate ; Catchment areas ; Hydrological data ; Impact assessment ; Models ; Flow discharge ; Runoff ; Land use ; Seasonal variation / China / Nepal / India / Koshi River Basin
(Location: IWMI HQ Call no: IWMI Record No: H049130)
(8 MB)
The Koshi Basin, spread across China, Nepal and India, is perceived as having high potential for hydropower and irrigation development, both seen as ways to promote economic development in the region. This paper quantifies and assesses the past and projected future spatial and temporal water balances in the Koshi Basin. Results show that precipitation and net water yield are lowest in the transmountain region and the Tibetan plateau. The values are highest in the mountain region, followed by the hills and Indo-Gangetic Plains. Approximately 65% of average annual precipitation is converted to flows, indicating high water availability. Actual evapotranspiration is highest in the Indo-Gangetic Plains region due to the presence of irrigated agriculture and a few forested mountain watersheds. As most of the water from the mountain and hill regions eventually flows down to the plains, the mountain and hill regions in Nepal are important for maintaining agriculture in the plains in both Nepal and India. Results from the flow analyses indicate the high temporal variability of flows in the basin. The frequent occurrences of both high- and low-flow events demonstrate the existing vulnerability of the region to both floods and droughts, leading to a very risk-prone livelihood system. Climate change projections show an increasing trend in precipitation and net water yield for most of the basin, except the transmountain region. Therefore, it is important to consider the climate change impacts on water resources in future planning.
9 Mandal, U. K.; Burman, D.; Bhardwaj, A. K.; Nayak, D. B.; Samui, A.; Mullick, S.; Mahanta, K. K.; Lama, T. D.; Maji, B.; Mandal, S.; Raut, S.; Sarangi, S. K. 2019. Waterlogging and coastal salinity management through land shaping and cropping intensification in climatically vulnerable Indian Sundarbans. Agricultural Water Management, 216:12-26. [doi: https://doi.org/10.1016/j.agwat.2019.01.012]
Waterlogging ; Coastal soils ; Soil salinity ; Land use ; Crops ; Intensification ; Climate change ; Water footprint ; Farm ponds ; Water balance ; Water productivity ; Soil water balance ; Rainwater harvesting ; Runoff ; Evapotranspiration / India / West Bengal / Sundarbans
(Location: IWMI HQ Call no: e-copy only Record No: H049349)
(1.76 MB)
Sundarbans in West Bengal, India located in the eastern coast of the Bay of Bengal is one of the vulnerable zones subjected to abrupt climate change. The region receives 2.7 times surplus rainfall as compared to crop evapotranspiration during monsoon months causing widespread waterlogging of the low lying agricultural fields and impedes the productivity. The present study assessed the effects of different land shaping models namely, farm pond (FP), deep furrow and high ridge (RF) and paddy cum fish (PCF) systems for rainwater harvesting in restoring the productivity of degraded coastal soils in Sundarbans. A water balance was run to estimate the soil moisture, crop evapotranspiration, runoff and water depth in the reservoir during normal, excess and deficit rainfall years. The average annual harvested runoff was 2709, 1650 and 1169 m3 per hectare in FP, RF and PCF systems, respectively. The runoff going out of the system was 19.5, 29.1 and 27.75% of the annual rainfall in FP, RF and PCF systems, respectively, whereas in monocrop rice-fallow system it was 34.6% of the annual rainfall. We estimated all the three components of water footprints (WF) i.e., blue WF (WFblue), green WF (WFgreen) and gray WF (WFgray) as an aggregative indicator to evaluate environmental impact. The results indicated that total as well as the components of WF was higher in rice-fallow and rice-rice systems than in each of the land shaping system. Large scale adoption of different land shaping systems increased the cropping intensity and net farm income and there was reduction in salinity during summer and waterlogging during rainy season and overall improvement in soil quality. The dominant soluble salts identified in the study region were NaCl and MgSO4
10 Pocas, I.; Calera, A.; Campos, I.; Cunha, M. 2020. Remote sensing for estimating and mapping single and basal crop coefficientes: a review on spectral vegetation indices approaches. Agricultural Water Management, 233:106081. [doi: https://doi.org/10.1016/j.agwat.2020.106081]
Remote sensing ; Crops ; Water requirements ; Evapotranspiration ; Vegetation index ; Irrigation management ; Soil water balance ; Soil moisture ; Earth observation satellites ; Landsat ; Geographical information systems ; Monitoring ; Water stress ; Mapping ; Models
(Location: IWMI HQ Call no: e-copy only Record No: H049654)
(0.77 MB)
The advances achieved during the last 30 years demonstrate the aptitude of the remote sensing-based vegetation indices (VI) for the assessment of crop evapotranspiration (ETc) and irrigation requirements in a simple, robust and operative manner. The foundation of these methodologies is the well-established relationship between the VIs and the basal crop coefficient (Kcb), resulting from the ability of VIs to measure the radiation absorbed by the vegetation, as the main driver of the evapotranspiration process. In addition, VIs have been related with single crop coefficient (Kc), assuming constant rates of soil evaporation. The direct relationship between VIs and ET is conceptually incorrect due to the effect of the atmospheric demand on this relationship. The rising number of Earth Observation Satellites potentiates a data increase to feed the VI-based methodologies for estimating and mapping either the Kc or Kcb, with improved temporal coverage and spatial resolution. The development of operative platforms, including satellite constellations like Sentinels and drones, usable for the assessment of Kcb through VIs, opens new possibilities and challenges. This work analyzes some of the questions that remain inconclusive at scientific and operational level, including: (i) the diversity of the Kcb-VI relationships defined for different crops, (ii) the integration of Kcb-VI relationships in more complex models such as soil water balance, and (iii) the operational application of Kcb-VI relationships using virtual constellations of space and aerial platforms that allow combining data from two or more sensors.
11 Garrido-Rubio, J.; Gonzalez-Piqueras, J.; Campos, I.; Osann, A.; Gonzalez-Gomez, L.; Calera, A. 2020. Remote sensing-based soil water balance for irrigation water accounting at plot and water user association management scale. Agricultural Water Management, 238:106236. (Online first). [doi: https://doi.org/10.1016/j.agwat.2020.106236]
Irrigation water ; Water accounting ; Remote sensing ; Soil water balance ; Water user associations ; Water management ; Irrigated farming ; Wheat ; Maize ; Barley ; Evapotranspiration ; Irrigated sites ; Satellite imagery ; Monitoring ; Models / Spain
(Location: IWMI HQ Call no: e-copy only Record No: H049697)
(3.35 MB)
Irrigation water accounting (IWA) plays a key role in irrigation management in arid or semi-arid environments. Currently, water managers perform IWA through indirect or direct measurements such as statistical methods or flow meters. However, they have a high maintenance cost and great efforts must be done when large irrigated areas must be covered. The presented framework based on the dual crop coefficient FAO56 methodology introduces an operative application of a Remote Sensing-based Soil Water Balance (RS-SWB) to obtain a Remote Sensing-based Irrigation Water Accounting (RS-IWA). A basic input of the model is the time series of basal crop coefficient and fractional vegetation cover. It has been implemented in a large water user association (100,000 ha) along three years (2010-2012). The results are analysed from the perspective of two water management scales: the plot and the water user association. At plot scale, the RS-IWA of maize and wheat, as primary crops irrigated on demand, show a root square mean error (RMSE) of about 12 % compared with the records from local farmers. At water user association management scale, the results from RS-IWA show an RMSE of about 15 % for a comprehensive range of irrigated crops group such as spring crops, summer crops, double harvest, alfalfa, and vineyards. Hence, RS-IWA based on RS-SWB offers reproducible and reliable mapped estimations that can be used for different water managers, as they are being required from actual agro-environmental laws that are pushing these actors to better knowledge in time and space of those water resources applied.
12 Pereira, L. S.; Paredes, P.; Melton, F.; Johnson, L.; Wang, T.; Lopez-Urrea, R.; Cancela, J. J.; Allen, R. G. 2020. Prediction of crop coefficients from fraction of ground cover and height. Background and validation using ground and remote sensing data. Agricultural Water Management, 241:106197. (Online first) [doi: https://doi.org/10.1016/j.agwat.2020.106197]
Crops ; Forecasting ; Remote sensing ; Satellites ; Evapotranspiration ; Vegetation ; Irrigation management ; Water stress ; Water management ; Energy balance ; Indicators ; Vegetable crops ; Field crops ; Soil water balance
(Location: IWMI HQ Call no: e-copy only Record No: H049857)
(2.32 MB)
The current study aims at reviewing and providing advances on methods for estimating and applying crop coefficients from observations of ground cover and vegetation height. The review first focuses on the relationships between single Kc and basal Kcb and various parameters including the fraction of ground covered by the canopy (fc), the leaf area index (LAI), the fraction of ground shaded by the canopy (fshad), the fraction of intercepted light (flight) and intercepted photosynthetic active radiation (fIPAR). These relationships were first studied in the 1970’s, for annual crops, and later, in the last decennia, for tree and vine perennials. Research has now provided a variety of methods to observe and measure fc and height (h) using both ground and remote sensing tools, which has favored the further development of Kc related functions. In the past, these relationships were not used predictively but to support the understanding of dynamics of Kc and Kcb in relation to the processes of evapotranspiration or transpiration, inclusive of the role of soil evaporation. Later, the approach proposed by Allen and Pereira (2009), the A&P approach, used fc and height (h) or LAI data to define a crop density coefficient that was used to directly estimate Kc and Kcb values for a variety of annual and perennial crops in both research and practice. It is opportune to review the A&P method in the context of a variety of studies that have derived Kc and Kcb values from field measured data with simultaneously observed ground cover fc and height. Applications used to test the approach include various tree and vine crops (olive, pear, and lemon orchards and vineyards), vegetable crops (pea, onion and tomato crops), field crops (barley, wheat, maize, sunflower, canola, cotton and soybean crops), as well as a grassland and a Bermudagrass pasture. Comparisons of Kcb values computed with the A&P method produced regression coefficients close to 1.0 and coefficients of determination = 0.90, except for orchards. Results indicate that the A&P approach can produce estimates of potential Kcb, using vegetation characteristics alone, within reasonable or acceptable error, and are useful for refining Kcb for conditions of plant spacing, size and density that differ from standard values. The comparisons provide parameters appropriate to applications for the tested crops. In addition, the A&P approach was applied with remotely sensed fc data for a variety of crops in California using the Satellite Irrigation Management Support (SIMS) framework. Daily SIMS crop ET (ETc-SIMS) produced Kcb values using the FAO56 and A&P approaches. Combination of satellite derived fc and Kcb values with ETo data from Spatial CIMIS (California Irrigation Management Information System) produced ET estimates that were compared with daily actual crop ET derived from energy balance calculations from micrometeorological instrumentation (ETc EB).Results produced coefficients of regression of 1.05 for field crops and 1.08 for woody crops, and R2 values of 0.81 and 0.91, respectively. These values suggest that daily ETc-SIMS -based ET can be accurately estimated within reasonable error and that the A&P approach is appropriate to support that estimation. It is likely that accuracy can be improved via progress in remote sensing determination of fc. Tabulated Kcb results and calculation parameters are presented in a companion paper in this Special Issue.
13 Nouri, H.; Nagler, P.; Borujeni, S. C.; Munez, A. B.; Alaghmand, S.; Noori, B.; Galindo, A.; Didan, K. 2020. Effect of spatial resolution of satellite images on estimating the greenness and evapotranspiration of urban green spaces. Hydrological Processes, 34(15):3183-3199. [doi: https://doi.org/10.1002/hyp.13790]
Urban areas ; Evapotranspiration ; Satellite imagery ; Remote sensing ; Landsat ; Moderate resolution imaging spectroradiometer ; Soil water balance ; Estimation ; Normalized difference vegetation index ; Sustainability / Australia / Adelaide
(Location: IWMI HQ Call no: e-copy only Record No: H049915)
https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.13790
https://vlibrary.iwmi.org/pdf/H049915.pdf
https://vlibrary.iwmi.org/pdf/H049915.pdf
(4.14 MB) (4.14 MB)
Urban green spaces (UGS), like most managed land covers, are getting progressively affected by water scarcity and drought. Preserving, restoring and expanding UGS require sustainable management of green and blue water resources to fulfil evapotranspiration (ET) demand for green plant cover. The heterogeneity of UGS with high variation in their microclimates and irrigation practices builds up the complexity of ET estimation. In oversized UGS, areas too large to be measured with in situ ET methods, remote sensing (RS) approaches of ET measurement have the potential to estimate the actual ET. Often in situ approaches are not feasible or too expensive. We studied the effects of spatial resolution using different satellite images, with high-, medium- and coarse-spatial resolutions, on the greenness and ET of UGS using Vegetation Indices (VIs) and VI-based ET, over a 780-ha urban park in Adelaide, Australia. We validated ET with the ground-based ET method of Soil Water Balance. Three sets of imagery from WorldView2, Landsat and MODIS, and three VIs including the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Enhanced Vegetation Index 2 (EVI2), were used to assess long-term changes of VIs and ET calculated from the different imagery acquired for this study (2011–2018). We found high correspondence between ET-MODIS and ET-Landsat (R2 > 0.99 for all VIs). Landsat-VIs captured the seasonal changes of greenness better than MODIS-VIs. We used artificial neural network (ANN) to relate the RS-ET and ground data, and ET-MODIS (EVI2) showed the highest correlation (R2 = 0.95 and MSE =0.01 for validation). We found a strong relationship between RS-ET and in situ measurements, even though it was not explicable by simple regressions; black box models helped us to explore their correlation. The methodology used in this research makes a strong case for the value of remote sensing in estimating and managing ET of green spaces in water-limited cities.
14 Lalehzari, R.; Kerachian, R. 2020. Developing a framework for daily common pool groundwater allocation to demands in agricultural regions. Agricultural Water Management, 241:106278. (Online first) [doi: https://doi.org/10.1016/j.agwat.2020.106278]
Groundwater ; Water allocation ; Agricultural regions ; Irrigation systems ; Irrigation water ; Water productivity ; Cropping patterns ; Crop water use ; Soil water balance ; Water supply ; Decision making ; Strategies ; Economic aspects ; Models ; Uncertainty / Iran Islamic Republic / Shahrekord Plain
(Location: IWMI HQ Call no: e-copy only Record No: H049923)
(5.95 MB)
In this paper, a new methodology is developed for the allocation of groundwater to agricultural lands considering the cultivated area of different crops, selling price and net benefit of products, and crops’ water requirements. The methodology includes an integrated model with daily time steps for simulating soil water balance, cultivar growth, and groundwater level fluctuations. The developed simulation model is linked with a particle swarm optimization model to find the optimal net benefit of beneficiaries. The non-dominated sorting genetic algorithm is also implemented to evaluate the fuzzy responses of the model against the existing uncertainty in the water supply. To evaluate the applicability and efficiency of the proposed methodology, it is applied to a real-world common pool groundwater allocation for agricultural uses in Iran. The results show that a centralized water allocation strategy can increase water productivity under water stress conditions by more than 0.2 kg/m3 for wheat, and barley. This policy can also provide the highest values for the benefit per cost ratio and the economic efficiency of land.
15 Eshete, D. G.; Tilahun, S. A.; Moges, M. A.; Schmitter, Petra; Dokou, Z.; Sinshaw, B. G.; Atalay, E. B.; Moges, M. A.; Takele, D. Y.; Getie, W. A. 2020. Evaluation of shallow ground water recharge and its potential for dry season irrigation at Brante Watershed, Dangila, Ethiopia. In Habtu, N. G.; Ayele, D. W.; Fanta, S. W.; Admasu, B. T.; Bitew, M. A. (Eds.). Advances of science and technology. Proceedings of the 7th EAI International Conference on Advancement of Science and Technology (ICAST 2019), Bahir Dar, Ethiopia, 2-4 August 2019. Cham, Switzerland: Springer. pp.148-168. (Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering (LNICST) Volume 308) [doi: https://doi.org/10.1007/978-3-030-43690-2_11]
Groundwater recharge ; Estimation ; Irrigation water ; Groundwater irrigation ; Dry season ; Groundwater table ; Soil water balance ; Crop water use ; Water requirements ; Evapotranspiration ; Rain ; Wells ; Discharges ; Watersheds ; Models / Ethiopia / Dangila / Brante Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H050059)
(21.30 MB)
The estimation of crop water demand and understanding groundwater use is an essential component for managing water effectively. Groundwater is the main source of irrigation in Dangila. However, there is a lack of information in the study area on amount of irrigated land, irrigation water use and demand, groundwater recharge. Consequently, the objective of this study is to determine the groundwater recharge and its potential for dry season irrigation. The study was conducted in Brante watershed of 5678 ha located in Dangila woreda, Ethiopia. Water table data from twenty-five wells and discharge data at the outlet of the watershed used to assess recharge amount in 2017. To calculate irrigation water demand, CROPWAT model was used. Questionnaires were undertaken to assess groundwater use. A KOMPSAT-2 image was used to map shallow groundwater irrigated vegetables in February 2017. From the soil water balance method, the annual groundwater recharge was 17,717,690 m3 which is 15.8% of annual rainfall, and recharge amount of 14,853,339 m3 was obtained using water table fluctuation method. From satellite image classification the area coverage of dry season irrigated vegetables (onion, tomato, pepper) below the main road was 4.02 ha. From CROPWAT result, seasonal irrigation water demand for onion, Tomato, and pepper was 333,314, and 261 mm respectively. However, the questioners result indicates that farmers apply in average 20% more water than crop water demand. In the watershed 60,150 m3, 62,750 m3 and 41,603 m3 of water was abstracted for irrigation, domestic and livestock use respectively. The ratio of groundwater use to groundwater recharge at the watershed scale was found to be only 1%. This study indicates that the current use of groundwater was sustainable. For better improvement of household livelihood irrigation can be further expand using ground water. Future work should be performed to determine if the method outlined in this research could be used to accurately estimate available water potential.
16 Simionesei, L.; Ramos, T. B.; Palma, J.; Oliveira, A. R.; Neves, R. 2020. IrrigaSys: a web-based irrigation decision support system based on open source data and technology. Computers and Electronics in Agriculture, 178:105822. [doi: https://doi.org/10.1016/j.compag.2020.105822]
Irrigation management ; Water management ; Decision support systems ; Databases ; Technology ; Irrigation scheduling ; Weather forecasting ; Soil water balance ; Irrigation water ; Irrigation systems ; Remote sensing ; Models ; Normalized difference vegetation index / Portugal / Sorraia Valley Irrigation District
(Location: IWMI HQ Call no: e-copy only Record No: H050091)
(2.85 MB)
IrrigaSys is a decision support system (DSS) for irrigation water management based on online, open source tools. The aim of this paper is to describe the structure of IrrigaSys and how it is implementation at the plot scale. The DSS includes remote access to local meteorological stations for weather conditions, a meteorological model for weather forecast, the MOHID-Land model for the computation of the soil water balance and irrigation scheduling, and a database for data repository. Despite its complexity, the data necessary to run IrrigaSys is minimal, and include as mandatory input information on the location of field plots, crop type, sowing and harvest dates, soil texture, irrigation method, and daily/weekly applied irrigation depths. Based on this information, the system automatically downloads the weather data from the meteorological station located closest to the agricultural plot, as well as the weather forecast for the seven incoming days. The soil water balance is then computed from sowing to the present date (updating always the system with newly acquired information) as well as the recommended irrigation schedule for the incoming week. Results are made available via a web interface, a mobile app, a SMS, and email. The IrrigaSys further provides the Normalized Difference Vegetation Index (NDVI) computed from the most recent Sentinel-2 imagery available with a resolution of 10 m. The IrrigaSys was developed in close cooperation with the Water Board from the Sorraia Valley irrigation district, southern Portugal, supporting 103 plots of 30 farmers over the last 5 years. This stakeholder has been fundamental for successfully running the system. This paper further discusses the main strengths and limitations of IrrigaSys, with the latter being naturally associated to difficulties in providing reliable estimates for all field plots based on limited data.
17 Mojid, M. A.; Mainuddin, M.; Murad, K. F. I.; Kirby, J. M. 2021. Water usage trends under intensive groundwater-irrigated agricultural development in a changing climate – evidence from Bangladesh. Agricultural Water Management, 251:106873. (Online first) [doi: https://doi.org/10.1016/j.agwat.2021.106873]
Water use ; Trends ; Agricultural development ; Climate change ; Groundwater irrigation ; Sustainability ; Irrigation requirements ; Cropping patterns ; Irrigation water ; Rain ; Soil water balance ; Agricultural planning ; Water demand ; Food security ; Evapotranspiration ; Models / Bangladesh / Rajshahi / Rangpur / Bogura / Chapainawabganj / Joypurhat / Naogaon / Natore / Pabna / Sirajganj / Thakurgaon / Panchagarh / Nilphamari / Lalmonirhat / Kurigram / Gaibandha / Dinajpur
(Location: IWMI HQ Call no: e-copy only Record No: H050326)
(17.00 MB)
Comprehensive information on the past trend of local-level water usage of the cultivated crops is important for agricultural planning and forecasting water needs. This vital information is however deficient for the North-West (NW) region of Bangladesh. We estimated actual crop evapotranspiration (ET), total and crop-usable effective rainfalls (TER and ER, respectively) and irrigation requirement (IR) of 8 major crops and 8 cropping patterns over historical period (1985–2015) by using SWBcropwat model and trends of these water parameters by using MAKESENS tool for the 16 districts of the region. ET of the Rabi crops and cropping patterns revealed significant (p = 0.05) decreasing trends in all districts, the average decrease being 13–31% in different districts. ER decreased significantly for most dry season crops in 4 districts. TER was often greater than ER for Kharif crops, which could not fully utilize TER always because of its non-uniform temporal distributions. IR showed significantly decreasing trend for the Rabi crops in 11 districts and increasing trend for the Kharif crops in 5 districts. Although ET and IR decreased in most cases, their total volumetric quantities showed significantly increasing trends due to expanded irrigated area in 16 districts over time; IR increased by 27–186% in different districts. Because of water scarcity and prospective economic benefit, farmers have been spontaneously adjusting crop selection – shifting from higher-water demanding crops to lower water-demanding crop-cultivation – during the last two decades. Our information would guide planning the agriculture of the NW region by selecting appropriate crops based on sustainable limit of groundwater resources. The employed methodology can evaluate crop suitability periodically for adjustment in any area.
18 Siavashani, N. S.; Jimenez-Martinez, J.; Vaquero, G.; Elorza, F. J.; Sheffield, J.; Candela, L.; Serrat-Capdevila, A. 2021. Assessment of CHADFDM satellite-based input dataset for the groundwater recharge estimation in arid and data scarce regions. Hydrological Processes, 35(6):e14250. [doi: https://doi.org/10.1002/hyp.14250]
Groundwater recharge ; Satellites ; Datasets ; Weather data ; Semiarid zones ; Precipitation ; Drought ; Rain ; Evapotranspiration ; Irrigated land ; Soil water balance ; Water resources ; Aquifers ; Air temperature ; Remote sensing ; Sensitivity analysis ; Uncertainty ; Models / Chad / Niger / Nigeria / Lake Chad Basin
(Location: IWMI HQ Call no: e-copy only Record No: H050431)
https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.14250
https://vlibrary.iwmi.org/pdf/H050431.pdf
https://vlibrary.iwmi.org/pdf/H050431.pdf
(3.85 MB) (3.85 MB)
Aquifer natural recharge estimations are a prerequisite for understanding hydrologic systems and sustainable water resources management. As meteorological data series collection is difficult in arid and semiarid areas, satellite products have recently become an alternative for water resources studies. A daily groundwater recharge estimation in the NW part of the Lake Chad Basin, using a soil–plant-atmosphere model (VisualBALAN), from ground- and satellite-based meteorological input dataset for non-irrigated and irrigated land and for the 2005–2014 period is presented. Average annual values were 284 mm and 30°C for precipitation and temperature in ground-based gauge stations. For the satellite-model-based Lake Chad Basin Flood and Drought Monitor System platform (CHADFDM), average annual precipitation and temperature were 417 mm and 29°C, respectively. Uncertainties derived from satellite data measurement could account for the rainfall difference. The estimated mean annual aquifer recharge was always higher from satellite- than ground-based data, with differences up to 46% for dryland and 23% in irrigated areas. Recharge response to rainfall events was very variable and results were very sensitive to: wilting point, field capacity and curve number for runoff estimation. Obtained results provide plausible recharge values beyond the uncertainty related to data input and modelling approach. This work prevents on the important deviations in recharge estimation from weighted-ensemble satellite-based data, informing in decision making to both stakeholders and policy makers.
19 Ali, A. A.; Bouchaou, L.; Er-Raki, S.; Hssaissoune, M.; Brouziyne, Youssef; Ezzahar, J.; Khabba, S.; Chakir, A.; Labbaci, A.; Chehbouni, A. 2023. Assessment of crop evapotranspiration and deep percolation in a commercial irrigated citrus orchard under semi-arid climate: combined Eddy-Covariance measurement and soil water balance-based approach. Agricultural Water Management, 275:107997. [doi: https://doi.org/10.1016/j.agwat.2022.107997]
Irrigated farming ; Citrus ; Evapotranspiration ; Deep percolation ; Semiarid climate ; Commercial farming ; Soil water balance ; Energy balance ; Agriculture ; Water management ; Irrigation management ; Irrigation scheduling ; Water supply ; Water stress ; Rain ; Crop water use ; Mediterranean climate ; Eddy covariance / Morocco / Souss-Massa
(Location: IWMI HQ Call no: e-copy only Record No: H051504)
https://www.sciencedirect.com/science/article/pii/S0378377422005443/pdfft?md5=d4f0a4edbb61d5f3f910c624caa72c48&pid=1-s2.0-S0378377422005443-main.pdf
https://vlibrary.iwmi.org/pdf/H051504.pdf
https://vlibrary.iwmi.org/pdf/H051504.pdf
(3.43 MB) (3.43 MB)
An accurate estimate of crop coefficient (Kc) values at different development stages (Kcini, Kcmid, and Kcend) is crucial for assessing crop water requirements in semi-arid regions. The objectives of this study were first to quantify the reference evapotranspiration (ETo) and to calculate the actual evapotranspiration (ETa) over citrus in a semi-arid climate under drip irrigation. For this purpose, a site of a citrus orchard in Souss-Massa, planted with the Esbal variety of clementine, was equipped with an Eddy-Covariance (EC) system, and sensors to measure radiation, soil heat flux, and micrometeorological forcing data, during 2020 and 2021 seasons. Also, the soil moisture content at various soil depths in the root zone near the EC tower was monitored. The energy balance closure (EBC) approach was adopted for flux assessment to ensure a quality check for the EC measurements. The obtained EBCs were about 82% and 79% for the daily measurements in 2020 and 2021, respectively, which can be considered acceptable considering the nature of the citrus orchard (relatively tall and sparse). Second, the study aimed to estimate actual Kc act values for citrus under the same irrigation strategy. The derived values were compared to different recommended Kc values in the literature. In the third stage, this work aimed to offer an alternative plan to sustainable irrigation management by elaborating an irrigation schedule for citrus crops in the region using the FAO-56 simple approach to avoid water stress and deep percolation (i.e., Ks = 1 and DP = 0). Eventually, an irrigation schedule was drawn following the crop’s phenological stages. The seasonal mean citrus evapotranspiration (ETa) values are 1.68, 3.02, and 1.86 mm/day for the initial, mid, and end-season. The seasonal actual Kc act values were 0.64, 0.58, and 0.64 for Kcini, Kcmid, and Kcend, respectively. Additionally, the application of the water balance equation revealed that a large quantity of water is lost through deep percolation (52% of total water supplied). The study focuses on Citrus trees being a strategic crop with important socio-economic values in the Souss-Massa region. Thus, the results should support both scientists and farmers in planning and strategy development.
20 Chunga, B. A.; Marx, W.; Cai, Xueliang; de Clercq, W.; Watson, A.; Malota, M. 2023. Water allocation using system dynamic modelling in the aquaculture integrated with small-scale irrigation systems in Malawi. Physics and Chemistry of the Earth, 129:103355. [doi: https://doi.org/10.1016/j.pce.2022.103355]
Water allocation ; Modelling ; Aquaculture ; Small-scale irrigation ; Decision support systems ; Fish ponds ; Maize ; Crop production ; Soil water balance ; Water depth ; Water-use efficiency ; Biomass production ; Crop yield ; Water resources ; Rainfall ; Rural areas ; Farmers ; Climate change / Malawi / Zomba / Chingale
(Location: IWMI HQ Call no: e-copy only Record No: H051813)
(5.07 MB)
The agricultural sector is faced with numerous challenges including climate change and water scarcity in many developing countries. In order to address scarcity and improve water use efficiency for rural farmers, fish farming is being integrated with small-scale irrigation. However, there are challenges in how to allocate water between the two farming enterprises. This study explored the capabilities of system dynamics to allocate water between a fish pond and a crop field in Chingale, Malawi using a system dynamic software, Vensim™ PLE. For soil water and pond water, a simple water balance structure was built and connected to the crop growth structure. Simulations run for 125 days corresponding to the maize growth period. Model results are similar to the actual yield (about 3.5 ton/ha for hybrid) and biomass production (about 7 ton/ha) in the area. Results also show it was possible to maintain pond water depth at recommended depths for raising fish: fish stocking (1 m), operation of the pond (1.5–2.0 m) and harvesting of the fish (less than 1.2 m) throughout the maize growing period. While the study did not comprehensively build and simulate fish growth, the use of such simple tools would benefit rural farmers with few resources. Based on the promising capabilities and the results of the tool it is recommended that further comprehensive analysis to fully incorporate all key sub-components affecting crop and fish growth be carried out.
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