Your search found 29 records
1 Muthuwatta, Lal; Jayakody, Priyantha. 2006. Development and testing a spatially distributed hydrological model for meso-scale watershed: A case study from Hulanda Oya catchment Sri Lanka. In Dayawansa, N. D. K. (Ed.). Geo-Informatics for Environmental Conservation and Management: Proceedings of the Third National Symposium on Geo-Informatics, 25 August 2006. Peradeniya, Sri Lanka: Geo-Informatics Society of Sri Lanka (GISSL) pp.59-71.
Watersheds ; Catchment areas ; Hydrology ; Simulation models ; GIS / Sri Lanka / Walawe basin / Hulanda Oya Catchment / Chandrika Wewa
(Location: IWMI-HQ Call no: 526.0285 G570 DAY Record No: H039756)
(0.76 MB)
2 Ahmad, Mobin-ud-Din; Islam, Aminul; Masih, Ilyas; Muthuwatta, Lal; Karimi, Poolad; Turral, Hugh. 2008. Mapping basin level water productivity using remote sensing and secondary data in the Karkheh River Basin, Iran. Paper presented at the 13th IWRA World Water Congress on Global Changes and Water Resources, "Confronting the expanding and diversifying pressures", Montpellier, France, 1-4 September 2008. 13p.
Water productivity ; Evapotranspiration ; Mapping ; River basins ; Farming systems / Iran / Karkheh River Basin
(Location: IWMI HQ Call no: IWMI 333.9162 G690 AHM Record No: H041537)
Water productivity (WP) mapping is essential to evaluate the performance of current water use at the river basin scale. WP mapping is also essential to identify opportunities to improve the net gain from water by either increasing the productivity for a given consumption of water or reducing consumption without decreasing production. This requires the computation of all benefits and overall water use at a similar spatial domain. Generally the secondary data related to agricultural, livestock and poultry production are managed at administrative district level, whereas hydrological data are collected at sub-watershed scale. This scale difference, hinders estimation at hydrological scales such as sub-catchment to river basin. Due to these limitations, estimates of WP beyond field and farm scale usually do not exist, as is the case of the Karkheh River basin of Iran. To address these issues, in this paper we demonstrate an approach to estimate WP at different scales using a range of datasets. To understand the productivity gaps within and between sub-basins of the Karkheh Basin, we assessed land and water productivity for major crops using a questionnaire survey of 298 farmers. The farm-level land and water productivity in irrigated areas was considerably higher than in rainfed areas. The yield of irrigated wheat and its WP, in terms of yield per unit of gross inflow, averaged 3320±1510 kg/ha and 0.55±0.20 kg/m3, whereas the corresponding values for rainfed wheat were 1460±580 kg/ha and 0.46±0.22 kg/m.For analysis from sub-catchment to basin scale, we assessed economic WP, in terms of gross value of production per unit of actual evapotranspiration, for all agricultural enterprises including rainfed and irrigated agriculture, livestock production and overall vegetation production using remote sensing data and routine secondary data/agricultural statistics. The sub-catchment estimates show that the water productivity variability is quite high: 0.027-0.071 $/m3 and 0.120-0.524 $/m3 for rainfed and irrigated systems respectively. Inclusion of livestock changes both the magnitude and patterns of overall water productivity and in doing so highlights the importance of fully accounting for all components in agricultural production systems. The WP mapping exercise presented in this paper identified both bright- and hot-spots for helping policy makers and managers to target better resource (re)allocation and measures to enhance productivity in the Karkheh Basin. The approach is applicable to other river basins.
3 McCartney, Matthew; Forkuor, Gerald; Sood, Aditya; Amisigo, B.; Hattermann, F.; Muthuwatta, Lal. 2012. The water resource implications of changing climate in the Volta River Basin [Africa]. Colombo, Sri Lanka: International Water Management Institute (IWMI). 33p. (IWMI Research Report 146) [doi: https://doi.org/10.5337/2012.219]
River basins ; Climate change ; Water resources development ; Reservoirs ; Water demand ; Temperature ; Rain ; Evapotranspiration ; Hydrology ; Flow discharge ; Groundwater recharge ; Surface water ; Water storage ; Simulation models ; Water power ; Irrigation schemes ; Irrigation water ; Water demand ; Livestock / Africa. / Volta River Basin
(Location: IWMI HQ Call no: IWMI Record No: H045520)
(1.99MB)
The Volta River is one of the major rivers in Africa. In this study, a dynamic regional climate model (CCLM), a hydrological model (SWAT) and a water resource model (WEAP) were used to provide an assessment of one downscaled ‘middle impact’ climate change scenario on the performance of existing and planned irrigation and hydropower schemes. The results indicate that, by the middle of the twenty-first century, altered climate is likely to undermine the technical performance of existing and planned reservoirs, which will, in turn, affect development outcomes. Future water resources development in the basin requires interventions that bolster resilience and water security. Much more systematic planning of water storage, greater cooperation between the riparian states and consideration of innovative approaches to water storage are needed.
4 Sood, Aditya; Muthuwatta, Lal; McCartney, Matthew. 2013. A SWAT evaluation of the effect of climate change on the hydrology of the Volta River Basin. Water International, 38(3):297-311. [doi: https://doi.org/10.1080/02508060.2013.792404]
Climate change ; Rain ; Temperature ; Hydrology ; River basins ; Flow discharge ; Water yield ; Groundwater recharge ; Water storage ; Weather data ; Reservoirs ; Calibration ; Models ; Statistical methods / West Africa / Volta River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H045833)
(3.29 MB)
The SWAT (Soil and Water Assessment Tool) was used to evaluate the impacts of a climate scenario based on IPCC A1B emissions on flows in the Volta River basin in West Africa for 2021–2050 and 2071–2100, using 1983–2012 as the reference period. Overall, the simulation indicates increased variability and a decrease of up to 40% in river flow as a consequence of decreasing rainfall and increasing temperature. In particular, the analysis shows smaller absolute but greater relative changes in the hydrology of the northern (upper) part of the basin, particularly at the end of the century.
5 Muthuwatta, Lal; Rientjes, T. H. M.; Bos, M. G. 2013. Strategies to increase wheat production in the water scarce Karkheh River Basin, Iran. Agricultural Water Management, 124:1-10. [doi: https://doi.org/10.1016/j.agwat.2013.03.013]
Irrigated farming ; Rainfed farming ; Wheat ; River basins ; Water productivity ; Water consumption ; Evapotranspiration ; Remote sensing ; Satellite surveys ; Rangelands ; Land use ; Land suitability / Iran / Karkheh River Basin
(Location: IWMI HQ Call no: PER Record No: H045834)
(2.15 MB)
Two strategies are assessed to increase wheat production in the water-scarce Karkheh River Basin (KRB) in Iran to meet targets by the year 2025. The strategies proposed are (a) to increase yields in the current irrigated and rainfed wheat areas and (b) to increase the area under rainfed wheat through land conversion. Crop water consumption, based on satellite remote sensing and crop yield data, was used to estimate crop water productivity (CWP) in irrigated and rainfed wheat areas in five sub-basins. CWP for wheat ranges from 0.5–1.63 kg m-3 in irrigated areas to 0.37–0.62 kg m-3 in rainfed areas. Conditions indicating water-stress in wheat areas were assessed by relative evapotranspiration (ETa/ETp) and showed that water-stress only had a minimal effect for about 154,000 ha of irrigated wheat (57%). Land suitability analysis showed that about 71,000 ha of rangelands can be converted into rainfed wheat areas without harming the current water balance in the basin. Statistical analyses showed that more than 70% of the variation in irrigated and rainfed wheat yield at plot level can be explained by water, fertilizer and seed rates. This suggests that wheat production can be increased by improving inputs other than water. Results from this study indicate that it is possible to meet approximately 85% of the wheat production targets in the year 2025 when strategies are combined.
6 Muthuwatta, Lal; Becht, R. 2004. Longterm rainfall - runoff modeling using the Soil and Water Assessment Tool (SWAT): a case study of the Lake Naivasha Basin, Kenya. In De Silva, R. P. (Ed.). Geo-informatics research and applications: proceedings of the First Symposium on Geo-informatics, Peradeniya, Sri Lanka, 30 July 2004. Peradeniya, Sri Lanka: Geo-Informatics Society of Sri Lanka (GISSL). pp.67-85.
Rain ; Runoff ; Simulation models ; Calibration ; Soil water ; Assessment ; Case studies ; Lakes ; Remote sensing ; Land use ; Watersheds / Kenya / Lake Naivasha Basin
(Location: IWMI HQ Call no: 621.3678 G000 DES Record No: H045956)
(1.42 MB)
7 Amarasinghe, Upali A.; Sharma, Bharat R.; Muthuwatta, Lal; Khan, Z. H. 2014. Water for food in Bangladesh: outlook to 2030. Colombo, Sri Lanka: International Water Management Institute (IWMI). 32p. (IWMI Research Report 158) [doi: https://doi.org/10.5337/2014.213]
Water supply ; Water demand ; Water productivity ; Groundwater ; Food supply ; Food consumption ; Rice ; Irrigated land ; Nutrients ; Animal products ; Feed crops ; Sustainability ; Forecasting / Bangladesh
(Location: IWMI HQ Call no: IWMI Record No: H046592)
(2.19 MB)
This research study shows that ‘business-as-usual’ scenarios will have substantial production surpluses of rice, which dominates water use patterns in the country at present. However, the surpluses come at a considerable environmental cost, due to high levels of groundwater depletion. Bangladesh can mitigate potential groundwater crises by limiting rice production to meet the requirements of self-sufficiency. Increases in water productivity of both Aman (wet season) and Boro (dry season) rice production can help too. A carefully designed deficit irrigation regime for Boro rice can also increase transpiration, yield, water productivity and production, and reduce the pressure on scarce groundwater resources.
8 Eriyagama, Nishadi; Muthuwatta, Lal; Thilakarathne, Madusanka. 2014. Minimizing flood damage and augmenting dry season water availability: prospects for floodwater harvesting and underground storage in Sri Lanka. In Sri Lanka. Ministry of Disaster Management. Proceedings of the Disaster Management Conference: The future we want- Safer Sri Lanka, Colombo, Sri Lanka, 24-26 September 2014. Colombo, Sri Lanka: Ministry of Disaster Management. pp.379-381.
Flooding ; Water harvesting ; Water availability ; Dry season ; Drought ; Groundwater management ; Groundwater recharge / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H046628)
(0.37 MB)
Flood water harvesting and underground storage is a concept that has received significant attention in many regions of the world. Its intention is to capture floodwater from currently flooded areas and to store it for later use, in order to both, reduce damage caused by floods, as well as to satisfy demands for water during drier periods. This paper presents a preliminary analysis of the prospects for its realization in Sri Lanka. A coarse scale suitability index is constructed and mapped at district level in order to identify the districts having higher prospects for its implementation. Preliminary results indicate three main clusters of highly suitable districts, subject to favourable geological conditions. Cluster 1 consists of Ampara and Batticalao, Cluster 2 of Kurunegala, Anuradhapura and Mannar, and Cluster 3 of Ratnapura. The potential for groundwater recharge of the highly suitable clusters need special investigation prior to arriving at concrete conclusions. If successfully implemented, this concept may prove a valuable intervention for adapting to current and future floods and droughts.
9 Muthuwatta, Lal; Sood, Aditya; Sharma, Bharat. 2014. Model to assess the impacts of external drivers on the hydrology of the Ganges River Basin. In Castellarin, A.; Ceola, S.; Toth, E.; Montanari, A. (Eds.). Evolving water resources systems: understanding, predicting and managing water-society interactions: proceedings of the 6th IAHS-EGU International Symposium on Integrated Water Resources Management, Bologna, Italy, 4-6 June 2014. Wallingford, UK: International Association of Hydrological Sciences (IAHS). pp.76-81.
Hydrology ; Models ; River basins ; Water yield ; Soils ; Assessment ; Climate change ; Precipitation ; Catchment areas ; Groundwater recharge / South East Asia / India / Nepal / Bangladesh / Tibet / Pakistan / Ganges River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H046673)
(1.40 MB)
Impact of climate change on the hydrology of the Ganges River Basin (GRB) is simulated by using a hydrological model – Soil and Water Assessment Tool (SWAT). Climate data from the GCM, Hadley Centre Coupled Model, version 3 (HadCM3) was downscaled with PRECIS for the GRB under A1B Special Report on Emission Scenarios (SRES) scenarios. The annual average precipitation will increase by 2.2% and 14.1% by 2030 and 2050, respectively, compared to the baseline period (1981–2010). Spatial distribution of the future precipitation shows that in the substantial areas of the middle part of the GRB, the annual precipitation in 2030 and 2050 will be reduced compared to the baseline period. Simulations indicate that in 2050 the total groundwater recharge would increase by 12%, while the increase of evapotranspiration will be about 10% compared to the baseline period. The water yield is also expected to increase in the future (up to 40% by 2050 compared to baseline), especially during the wetter months. The model setup is available for free from IWMI’s modelling inventory.
10 Muthuwatta, Lal; Liyanage, P. K. N. C. 2013. Impact of rainfall change on the agro-ecological regions of Sri Lanka. In Gunasena, H. P. M.; Gunathilake, H. A. J.; Everard, J. M. D. T.; Ranasinghe, C. S.; Nainanayake, A. D. (Eds.). Proceedings of the International Conference on Climate Change Impacts and Adaptations for Food and Environment Security on Sustaining Agriculture Under Changing Climate. Colombo, Sri Lanka, 30-31 July 2013. Lunuwila, Sri Lanka: Coconut Research Institute; Colombo, Sri Lanka: Ministry of Environment and Renewable Energy; New Delhi, India: World Agroforestry Center Regional Office. pp.59-66.
Climate change ; Climatic zones ; Agroecology ; Rain ; Arid zones ; Meteorological stations ; Temperature ; Evapotranspiration / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H046672)
(6.87 MB)
Changes in future rainfall distribution for the agro-ecological regions of Sri Lanka were analyzed. The baseline period to compare future predictions was taken as 1970 to 2000. Downscaled climate change prediction grids were extracted from the UK Hadley Centre for Climate Prediction and Research Model (HadCM3). These grids were extracted for 2050. In the baseline period 76 stations of147 showed decreasing trends in annual rainfall and 71 increasing trends. Thirty six of the 76 stations showing a decrease were in the wet zone. In the intermediate zone 17 stations showed increasing trends and in the dry zone 34 stations indicated increasing trends. Mean annual rainfall (MAR) for the baseline period for the whole country was 2094 mm/year while the projected value for 2050 is 2249 mm/year. The increase of MAR over Sri Lanka by 2050 compared to the baseline period is about 7%. The comparison of rainfall between the baseline period and 2050 showed that some areas of the dry zone will receive MAR of more than 1750 mm and could be classified and included into the intermediate zone by 2050. Further, the increase of MAR for 11 agroecological regions goes beyond the variability observed in the baseline data set.
11 Brindha, Karthikeyan; Pavelic, Paul; Lagudu, Surinaidu; Muthuwatta, Lal; Eriyagama, Nishadi; Amarnath, Giriraj; Smakhtin, Vladimir. 2014. Novel conjunctive groundwater-surface water management for controlling floods and droughts [Abstract only] Paper presented at the 41st IAH International Congress on Groundwater: Challenges and Strategies, Marrakech, Morocco, 15-19 September 2014. 1p.
Conjunctive use ; Groundwater ; Surface water ; Watershed management ; Flooding ; Drought ; River basins
(Location: IWMI HQ Call no: e-copy only Record No: H046779)
(0.04 MB)
Well-targeted programs of conjunctive use of groundwater and surface water can help overcome the problem of both floods and droughts, or in other terms meet the water demands for domestic as well as irrigation needs during the dry season. Addressing this, a novel form of conjunctive use management has been developed that involves strategically recharging floodwater in upstream areas to boost small-scale groundwater irrigation and to protect floodaffected areas downstream. For this, choice of site is a crucial component to implement the approach. A method was devised using GIS tools using readily available data from secondary sources to arrive at a suitability index to rank prospects across the entire Ganges basin. This basin was chosen because it has a well-known history of devastating flooding events and water shortage in dry months and is one of the largest and most heavily populated river basins in the world. Numerical modelling is being applied to an area characterized as having high prospects to help to understand the interactions between the groundwater and surface water and the impact of floods on groundwater system. One of the main components to be identified from the model is the peak flows to be captured successfully for recharge. This utilisation of high flows by diverting from the rivers to storage structures introduced within the model will help to identify the potential to manage and reduce the flood impact. This model can help to decide on the size and placement of the structures to store water for maximum recharge and subsequently in watershed management. The relationship between floodwater storage and recharge, and the optimisation of these two processes can also be brought out. Opportunities for conjunctive use of water identified by mapping and the understanding gained from modelling is to be piloted out in one of these sites to establish technical and institutional feasibility with the view to promoting larger-scale implementation.
12 Bastiaanssen, Wim G. M.; Karimi, Poolad; Rebelo, Lisa-Maria; Duan, Z.; Senay, G.; Muthuwatta, Lal; Smakhtin, Vladimir. 2014. Earth observation based assessment of the water production and water consumption of Nile Basin agro-ecosystems. Remote Sensing, 6(11):10306-10334. [doi: https://doi.org/10.3390/rs61110306]
Water requirements ; Water use ; Water accounting ; Water balance ; Groundwater ; Earth observation satellites ; Assessment ; Agroecosystems ; River basins ; Evapotranspiration ; Remote sensing ; Models ; Rain / Africa / Nile Basin
(Location: IWMI HQ Call no: e-copy only Record No: H046822)
(2.06 MB) (2.06 MB)
The increasing competition for water resources requires a better understanding of flows, fluxes, stocks, and the services and benefits related to water consumption. This paper explains how public domain Earth Observation data based on Moderate Resolution Imaging Spectroradiometer (MODIS), Second Generation Meteosat (MSG), Tropical Rainfall Measurement Mission (TRMM) and various altimeter measurements can be used to estimate net water production (rainfall (P) > evapotranspiration (ET)) and net water consumption (ET > P) of Nile Basin agro-ecosystems. Rainfall data from TRMM and the Famine Early Warning System Network (FEWS-NET) RainFall Estimates (RFE) products were used in conjunction with actual evapotranspiration from the Operational Simplified Surface Energy Balance (SSEBop) and ETLook models. Water flows laterally between net water production and net water consumption areas as a result of runoff and withdrawals. This lateral flow between the 15 sub-basins of the Nile was estimated, and partitioned into stream flow and non-stream flow using the discharge data. A series of essential water metrics necessary for successful integrated water management are explained and computed. Net water withdrawal estimates (natural and humanly instigated) were assumed to be the difference between net rainfall (Pnet) and actual evapotranspiration (ET) and some first estimates of withdrawals—without flow meters—are provided. Groundwater-dependent ecosystems withdraw large volumes of groundwater, which exceed water withdrawals for the irrigation sector. There is a strong need for the development of more open-access Earth Observation databases, especially for information related to actual ET. The fluxes, flows and storage changes presented form the basis for a global framework to describe monthly and annual water accounts in ungauged river basins.
13 Gunawardena, J.; Muthuwatta, Lal; Fernando, M. J. J.; Rathnayake, S.; Rodrigo, T. M. A. S. K.; Gunawardena, A. (Eds.) 2015. Proceedings of the First International Symposium on Environment Management and Planning, Battaramulla, Sri Lanka, 23-24 February 2015. Colombo, Sri Lanka: Central Environmental Authority (CEA). 55p.
Environmental management ; Forest plantations ; Drug plants ; Tea ; Rubber industry ; Agroforestry ; Biodiversity ; Wildlife ; Freshwater ; Water quality ; Groundwater pollution ; Water deficit ; Land use ; Paddy fields ; Constructed wetlands ; Carbon ; Meteorology ; Models ; Satellite surveys ; GIS ; Remote sensing ; Maps ; Soil salinity ; Erosion ; Sand ; Solar radiation ; Watersheds ; Aquifers ; River basins ; Tanks ; Energy generation ; Bioremediation ; Waste management ; Performance evaluation ; Toxic substances ; Pollutant load ; Noise pollution ; Denitrification ; Leachates ; Biofertilizers ; Aquatic insects ; Food production ; Fishing ; Farmers ; Vegetable growing ; Vermicomposting ; Health hazards ; Malaria ; Case studies ; Arid zones ; Coastal area ; Coral reefs / Sri Lanka / India / Tangalle / Vavuniya / Jaffna / Killinochchi / Mullaitivu / Mannar / Kalpitiya / Colombo / Kalutara / Matara / Weligama / Badulla / Upper Mahaweli Catchment / Paraviwella Reef / Vairavapuliyankulam Tank / Kelani River / Himalayan Region
(Location: IWMI HQ Call no: IWMI Record No: H046899)
(1.32 MB)
14 Pavelic, Paul; Brindha, Karthikeyan; Amarnath, Giriraj; Eriyagama, Nishadi; Muthuwatta, Lal; Smakhtin, Vladimir; Gangopadhyay, Prasun K.; Malik, Ravinder Paul Singh; Mishra, Atmaram; Sharma, Bharat R.; Hanjra, Munir A.; Reddy, R. V.; Mishra, V. K.; Verma, C. L.; Kant, L. 2015. Controlling floods and droughts through underground storage: from concept to pilot implementation in the Ganges River Basin. Colombo, Sri Lanka: International Water Management Institute (IWMI). 33p. (IWMI Research Report 165) [doi: https://doi.org/10.5337/2016.200]
Climate change ; Flood control ; Flood irrigation ; Floodplains ; Drought ; River basins ; Economic aspects ; Cost benefit analysis ; Corporate culture ; Groundwater depletion ; Groundwater recharge ; Groundwater irrigation ; Water storage ; Water resources ; Underground storage ; Subsurface runof ; Flow discharge ; Disaster risk reduction ; Impact assessment ; Case studies / South East Asia / India / Nepal / Bangladesh / Tibet / Ganges River Basin
(Location: IWMI HQ Call no: IWMI Record No: H047460)
(1 MB)
The concept of ‘Underground Taming of Floods for Irrigation’ (UTFI) is introduced as an approach for co-managing floods and droughts at the river basin scale. UTFI involves strategic recharge of aquifers upstream during periods of high flow, thereby preventing local and downstream flooding, and simultaneously providing additional groundwater for irrigation during the dry season for livelihood improvement. Three key stages in moving UTFI from the concept stage to mainstream implementation are discussed. An analysis of prospects in the Ganges River Basin are revealed from the earliest stage of mapping of suitability at the watershed level through to the latest stages of identifying and setting up the first pilot trial in the Upper Ganges, where a comprehensive evaluation is under way. If UTFI can be verified then there is enormous potential to apply it to address climate change adaptation/mitigation and disaster risk reduction challenges globally.
15 Amarasinghe, Upali Ananda; Muthuwatta, Lal; Surinaidu, L.; Anand, Sumit; Jain, S. K. 2016. Reviving the Ganges water machine: potential. Hydrology and Earth System Sciences, 20(3):1085-1101. [doi: https://doi.org/10.5194/hess-20-1085-2016]
Monsoon climate ; Water resources ; Water use ; Water supply ; Water storage ; Groundwater management ; Surface water ; River basins ; Riparian zones ; Irrigated land ; Farmland ; Environmental flows ; Flooding ; Recharge ; Runoff / South East Asia / India / Nepal / Bangladesh / Tibet / Ganges River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047467)
http://www.hydrol-earth-syst-sci.net/20/1085/2016/hess-20-1085-2016.pdf
https://vlibrary.iwmi.org/pdf/H047467.pdf
https://vlibrary.iwmi.org/pdf/H047467.pdf
(1.35 MB)
The Ganges River basin faces severe water challenges related to a mismatch between supply and demand. Although the basin has abundant surface water and groundwater resources, the seasonal monsoon causes a mismatch between supply and demand as well as flooding. Water availability and flood potential is high during the 3–4 months (June–September) of the monsoon season. Yet, the highest demands occur during the 8–9 months (October–May) of the non-monsoon period. Addressing this mismatch, which is likely to increase with increasing demand, requires substantial additional storage for both flood reduction and improvements in water supply. Due to hydrogeological, environmental, and social constraints, expansion of surface storage in the Ganges River basin is problematic. A range of interventions that focus more on the use of subsurface storage (SSS), and on the acceleration of surface–subsurface water exchange, has long been known as the Ganges Water Machine (GWM). The approach of the GWM for providing such SSS is through additional pumping and depleting of the groundwater resources prior to the onset of the monsoon season and recharging the SSS through monsoon surface runoff. An important condition for creating such SSS is the degree of unmet water demand. The paper shows that the potential unmet water demand ranging from 59 to 124 Bm3 year-1 exists under two different irrigation water use scenarios: (i) to increase irrigation in the Rabi (November–March) and hot weather (April–May) seasons in India, and the Aman (July–November) and Boro (December–May) seasons in Bangladesh, to the entire irrigable area, and (ii) to provide irrigation to Rabi and the hot weather season in India and the Aman and Boro seasons in Bangladesh to the entire cropped area. However, the potential for realizing the unmet irrigation demand is high only in 7 sub-basins in the northern and eastern parts, is moderate to low in 11 sub-basins in the middle, and has little or no potential in 4 sub-basins in the western part of the Ganges basin. Overall, a revived GWM plan has the potential to meet 45–84 Bm3year-1 of unmet water demand.
16 Amarasinghe, Upali Ananda; Muthuwatta, Lal; Surinaidu, L.; Anand, Sumit; Jain, S. K. 2015. Reviving the Ganges water machine: why? Hydrology and Earth System Sciences Discussions, 12:8727-8759. [doi: https://doi.org/10.5194/hessd-12-8727-2015]
Monsoon climate ; Water resources ; Water use ; Water supply ; Water storage ; Water demand ; Groundwater management ; Surface water ; River basins ; Riparian zones ; Irrigated land ; Environmental flows ; Flooding ; Recharge ; Runoff ; Rain / South East Asia / India / Nepal / Bangladesh / Tibet / Ganges River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047515)
http://www.hydrol-earth-syst-sci-discuss.net/12/8727/2015/hessd-12-8727-2015.pdf
https://vlibrary.iwmi.org/pdf/H047515.pdf
https://vlibrary.iwmi.org/pdf/H047515.pdf
(2.72 MB)
The Ganges River Basin may have a major pending water crisis. Although the basin has abundant surface water and groundwater resources, the seasonal monsoon causes a mismatch between supply and demand as well as flooding. Water availability and flood potential is high during the 3–4 months of the monsoon season. Yet, the highest demands occur during the 8–9 months of the non-monsoon period. Addressing this mismatch requires substantial additional storage for both flood reduction and improvements in water supply. Due to hydrogeological, environmental, and social constraints, expansion of surface storage in the Ganges River Basin is problematic. A range of in- terventions that focus more on the use of subsurface storage (SSS), and on the acceleration of surface–subsurface water exchange, have long been known as the “Ganges Water Machine”. One approach for providing such SSS is through additional pumping prior to the onset of the monsoon season. An important necessary condition for creating such SSS is the degree of unmet water demand. This paper highlights that an unmet water demand ranging from 59 to 119 Bm3 exists under two different irrigation water use scenarios: (i) to increase Rabi and hot weather season irrigation to the entire irrigable area, and (ii) to provide Rabi and hot weather season irrigation to the entire cropped area. This paper shows that SSS can enhance water supply, and provide benefits for irrigation and other water use sectors. In addition, it can buffer the inherent variability in water supply and mitigate extreme flooding, especially in the downstream parts of the basin. It can also increase river flow during low-flow months via baseflow or enable the re-allocation of irrigation canal water. Importantly, SSS can mitigate the negative effects of both flooding and water scarcity in the same year, which often affects the most vulnerable segments of society – women and children, the poor and other disadvantaged social groups.
17 Muthuwatta, Lal; Amarasinghe, Upali Ananda; Sood, Aditya; Lagudu, S. 2015. Reviving the “Ganges Water Machine”: where and how much? Hydrology and Earth System Sciences Discussions, 12:741-763. [doi: https://doi.org/10.5194/hessd-12-9741-2015]
Surface water ; Runoff water ; Monsoon climate ; Upstream ; Flooding ; River basin management ; Groundwater recharge ; Water storage ; Water availability ; Water demand ; Agriculture ; Soil management ; Soil water ; Flood control / South East Asia / India / Nepal / Bangladesh / Tibet / Ganges River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047516)
http://www.hydrol-earth-syst-sci-discuss.net/12/9741/2015/hessd-12-9741-2015.pdf
https://vlibrary.iwmi.org/pdf/H047516.pdf
https://vlibrary.iwmi.org/pdf/H047516.pdf
(5.02 MB)
Surface runoff generated in the monsoon months in the upstream parts of the Ganges River Basin contributes substantially to downstream floods, while water shortages in the dry months affect agricultural production in the basin. This paper examines the parts (sub-basins) of the Ganges that have the potential for augmenting subsurface storage (SSS), increase the availability of water for agriculture and other uses, and mitigate the floods in the downstream areas. The Soil and Water Assessment Tool (SWAT) is used to estimate sub-basin-wise water availability. The water availability estimated is then compared with the sub-basin-wise un-met water demand for agriculture. Hy-drological analyses revealed that five sub-basins produced more than 10 billion cubic meters (B m3) of annual surface runoff consistently during the simulation period. In these sub-basins, less than 50 % of the annual surface runoff is sufficient to irrigate all irrigable land in both the Rabi (November to March) and summer (April to May) seasons. Further, for most of the sub-basins, there is sufficient water to meet the un-met water demand, provided that it is possible to capture the surface runoff during the wet season. It is estimated that the average flow to Bihar State from the upstream of the Ganges, a downstream basin location, is 277 ± 121 B m3, which is more than double the rainfall in the state alone. Strong relationships between outflows from the upstream sub-basins and the inflows to Bihar State suggested that flood inundation in the state could be reduced by capturing a portion of the upstream flows during the peak runoff periods.
18 Surinaidu, L.; Muthuwatta, Lal; Amarasinghe, Upali Ananda; Jain, S. K.; Kumar, S.; Singh, S. 2016. Reviving the Ganges water machine: accelerating surface water and groundwater interactions in the Ramganga sub-basin. Journal of Hydrology, 540:207-219. [doi: https://doi.org/10.1016/j.jhydrol.2016.06.025]
Surface water ; Monsoon climate ; Groundwater recharge ; Water storage ; Water use ; Water levels ; Water balance ; Pumping ; Aquifers ; River basins ; Seepage ; Hydrogeology ; Models ; Calibration ; Flow discharge ; Artificial recharge ; Rain / South East Asia / India / Nepal / Bangladesh / Tibet / Ganges River Basin / Ramganga Sub-basin
(Location: IWMI HQ Call no: e-copy only Record No: H047599)
Reviving the Ganges Water Machine (GWM), coined 40 years ago, is the most opportune solution for mitigating the impacts of recurrent droughts and floods in the Ganges River Basin in South Asia. GWM create subsurface storage (SSS) by pumping more groundwater from the aquifers before the monsoon for irrigation and other uses and recharge it during the monsoon. The present study uses fully processed and physically based numerical models, MODFLOW and SWAT, in a semi-coupled modelling framework to examine the technical feasibility of recharging the SSS. The aquifer was simulated as a two-layer system using hydrogeological and groundwater data, model was calibrated from 1999 to 2005 and validated from 2006 to 2010. It assesses the impacts of gradual increase of SSS in 10 years from the base year 2010 under two scenarios (increased rainfall or controlled pumping and recharge) to meet a potential unmet demand of 1.68 billion cubic meters (Bm3) in the Ramganga sub-basin with an area of 18,668 km2. The results show that 3–4 m of subsurface storage can be created by groundwater pumping of 0.25 Bm3/year by 2020. Under the controlled pumping and recharge scenario, groundwater recharge and river seepage could increase by 14% (4.21–4.80 Bm3) and 31% (1.10–1.44 Bm3), respectively. However, baseflow will decrease by 30% (0.18–0.12 Bm3) over the same time period. The results also show that recharge increased 44% (4.21–6.05 Bm3) under an increased rainfall scenario. Simultaneously, river seepage and baseflows would increase 36% (1.10–1.14 Bm3) and 11% (0.18–0.20 Bm3), respectively. A well-designed managed aquifer recharge program is required to eliminate the negative impact of river flows in the low flow season.
19 Amarasinghe, Upali A.; Muthuwatta, Lal; Smakhtin, Vladimir; Surinaidu, Lagudu; Natarajan, R.; Chinnasamy, Pennan; Kakumanu, Krishna Reddy; Prathapar, Sanmugam A.; Jain, S. K.; Ghosh, N. C.; Singh, S.; Sharma, A.; Jain, S. K.; Kumar, S.; Goel, M. K. 2016. Reviving the Ganges water machine: potential and challenges to meet increasing water demand in the Ganges River Basin. Colombo, Sri Lanka: International Water Management Institute (IWMI). 42p. (IWMI Research Report 167) [doi: https://doi.org/10.5337/2016.212]
Water demand ; Water resources ; Water supply ; Water use ; Water storage ; Water quality ; Water accounting ; River basin management ; Groundwater irrigation ; Groundwater depletion ; Groundwater recharge ; Domestic water ; Irrigation water ; Surface water ; Runoff water ; Industrial uses ; Climate change ; Monsoon climate ; Flooding ; Drought ; Cost benefit analysis ; Aquifers ; Solar energy ; Renewable energy ; Pumping ; Cropping systems / South East Asia / India / Nepal / Bangladesh / Tibet / Ganges River Basin
(Location: IWMI HQ Call no: IWMI Record No: H047712)
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Although the Ganges River Basin (GRB) has abundant water resources, the seasonal monsoon causes a mismatch in water supply and demand, which creates severe water-related challenges for the people living in the basin, the rapidly growing economy and the environment. Addressing these increasing challenges will depend on how people manage the basin’s groundwater resources, on which the reliance will increase further due to limited prospects for additional surface storage development. This report assesses the potential of the Ganges Water Machine (GWM), a concept proposed 40 years ago, to meet the increasing water demand through groundwater, and mitigate the impacts of floods and droughts. The GWM provides additional subsurface storage (SSS) through the accelerated use of groundwater prior to the onset of the monsoon season, and subsequent recharging of this SSS through monsoon surface runoff. It was identified that there is potential to enhance SSS through managed aquifer recharge during the monsoon season, and to use solar energy for groundwater pumping, which is financially more viable than using diesel as practiced in many areas at present. The report further explores the limitations associated with water quality issues for pumping and recharge in the GRB, and discusses other related challenges, including availability of land for recharge structures and people’s willingness to increase the cropping intensity beyond the present level.
20 Amarasinghe, Upali A.; Muthuwatta, Lal. 2016. Ganges water machine: one solution to basin water problems? In Bharati, Luna; Sharma, Bharat R.; Smakhtin, Vladimir (Eds.). The Ganges River Basin: status and challenges in water, environment and livelihoods. Oxon, UK: Routledge - Earthscan. pp.154-171. (Earthscan Series on Major River Basins of the World)
Water resources ; Groundwater depletion ; Groundwater recharge ; Water use ; Water accounting ; Irrigation water ; Water demand ; Surface runoff ; Models ; Evapotranspiration ; Irrigated land ; Farmland ; Monsoon climate ; Rain ; River basins / India / Nepal / Bangladesh / Ganges River Basin
(Location: IWMI HQ Call no: IWMI Record No: H047814)
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