Your search found 4 records
1 de Silva, Sanjiv; Aheeyar, Mohamed; Arulingam, Indika; Manthrithilake, Herath. 2018. The new water: opportunities and challenges of the rise to prominence of groundwater in Sri Lanka in the face of socioeconomic and climatic change. In Mukherjee, A. (Ed.). Groundwater of South Asia. Berlin, Germany: Springer. pp.759-799.
Climatic change ; Climate change adaptation ; Socioeconomic environment ; Groundwater management ; Water governance ; Water availability ; Precipitation ; Rain ; Surface water ; Land area ; Dry season ; Rice ; Rainwater ; Water harvesting ; Water storage ; Water resources ; Irrigation water ; Irrigation schemes ; Seasonal cropping ; Poverty / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H048817)
(0.73 MB)
Overall high annual precipitation in Sri Lanka belies significant spatial and temporal variation in surface water availability. The ‘dry zone’ comprising two-third of Sri Lanka’s land area receives significantly less rainfall and has high precipitation rates and a five-month dry season. Nevertheless, these regions account for the majority of rice production, the staple crop, thanks largely to the ancient hydraulic civilization based on networks of rainwater harvesting (irrigation) tanks. This manipulation of surface water resources including modern surface irrigation schemes continues to form the backbone of dry zone farming. Groundwater irrigation has remained in the shadows except in the North where surface flows are absent. This scenario is now changing as population growth; poorly maintained infrastructure; commercial agriculture; sectoral competition for water and climate change combine to exert severe pressure on surface water resources. Since the dry zone is also home to a large number of Sri Lanka’s poor households, and a close association exists between high poverty clusters and access to irrigation, the implications of water insecurity for a range of poverty indicators are clear. Not surprisingly, these pressures have prompted an increasing recourse to groundwater in several parts of the dry zone, as governments and farmers recognize the imperative to increase agriculture output, promote crop diversification, and improve agrarian incomes. Yet, with limited groundwater potential, limited detailed knowledge of this resource, and under-developed groundwater-oriented institutions, it is far from certain whether future groundwater exploitation can steer away from anarchy.
2 Soulard, C. E.; Walker, J. J.; Petrakis, R. E. 2020. Implementation of a surface water extent model in Cambodia using cloud-based remote sensing. Remote Sensing, 12(6):984. (Special issue: Applying Earth Surface Monitoring to Investigate Climate and Land Change Interactions) [doi: https://doi.org/10.3390/rs12060984]
Surface water ; Models ; Remote sensing ; Mapping ; Flooding ; Floodplains ; Satellite imagery ; Landsat ; Hydrology ; Precipitation ; Land area ; Wetlands ; Vegetation / South East Asia / Cambodia
(Location: IWMI HQ Call no: e-copy only Record No: H049694)
(3.82 MB) (3.82 MB)
Mapping surface water over time provides the spatially explicit information essential for hydroclimatic research focused on droughts and flooding. Hazard risk assessments and water management planning also rely on accurate, long-term measurements describing hydrologic fluctuations. Stream gages are a common measurement tool used to better understand flow and inundation dynamics, but gage networks are incomplete or non-existent in many parts of the world. In such instances, satellite imagery may provide the only data available to monitor surface water changes over time. Here, we describe an effort to extend the applicability of the USGS Dynamic Surface Water Extent (DSWE) model to non-US regions. We leverage the multi-decadal archive of the Landsat satellite in the Google Earth Engine (GEE) cloud-based computing platform to produce and analyze 372 monthly composite maps and 31 annual maps (January 1988–December 2018) in Cambodia, a flood-prone country in Southeast Asia that lacks a comprehensive stream gage network. DSWE relies on a series of spectral water indices and elevation data to classify water into four categories of water inundation. We compared model outputs to existing surface water maps and independently assessed DSWE accuracy at discrete dates across the time series. Despite considerable cloud obstruction and missing imagery across the monthly time series, the overall accuracy exceeded 85% for all annual tests. The DSWE model consistently mapped open water with high accuracy, and areas classified as “high confidence” water correlate well to other available maps at the country scale. Results in Cambodia suggest that extending DSWE globally using a cloud computing framework may benefit scientists, managers, and planners in a wide array of applications across the globe.
3 Arsenault, K. R.; Shukla, S.; Hazra, A.; Getirana, A.; McNally, A.; Kumar, S. V.; Koster, R. D.; Peters-Lidard, C. D.; Zaitchik, B. F.; Badr, H.; Jung, H. C.; Narapusetty, B.; Navari, M.; Wang, S.; Mocko, D. M.; Funk, C.; Harrison, L.; Husak, G. J.; Adoum, A.; Galu, G.; Magadzire, T.; Roningen, J.; Shaw, M.; Eylander, J.; Bergaoui, K.; McDonnell, Rachael A.; Verdin, J. P. 2020. The NASA hydrological forecast system for food and water security applications. Bulletin of the American Meteorological Society (BAMS), 101(7):E1007-E1025. [doi: https://doi.org/10.1175/BAMS-D-18-0264.1]
Hydrology ; Forecasting ; Early warning systems ; Food security ; Water security ; Drought ; Flooding ; Precipitation ; Groundwater ; Water storage ; Soil water content ; Stream flow ; Monitoring ; Land area ; Meteorological factors ; Satellite observation ; Modelling / Africa / Middle East
(Location: IWMI HQ Call no: e-copy only Record No: H049803)
https://journals.ametsoc.org/bams/article-pdf/101/7/E1007/4981535/bamsd180264.pdf
https://vlibrary.iwmi.org/pdf/H049803.pdf
https://vlibrary.iwmi.org/pdf/H049803.pdf
(8.47 MB) (8.47 MB)
Many regions in Africa and the Middle East are vulnerable to drought and to water and food insecurity, motivating agency efforts such as the U.S. Agency for International Development’s (USAID) Famine Early Warning Systems Network (FEWS NET) to provide early warning of drought events in the region. Each year these warnings guide life-saving assistance that reaches millions of people. A new NASA multimodel, remote sensing–based hydrological forecasting and analysis system, NHyFAS, has been developed to support such efforts by improving the FEWS NET’s current early warning capabilities. NHyFAS derives its skill from two sources: (i) accurate initial conditions, as produced by an offline land modeling system through the application and/or assimilation of various satellite data (precipitation, soil moisture, and terrestrial water storage), and (ii) meteorological forcing data during the forecast period as produced by a state-of-the-art ocean–land–atmosphere forecast system. The land modeling framework used is the Land Information System (LIS), which employs a suite of land surface models, allowing multimodel ensembles and multiple data assimilation strategies to better estimate land surface conditions. An evaluation of NHyFAS shows that its 1–5-month hindcasts successfully capture known historic drought events, and it has improved skill over benchmark-type hindcasts. The system also benefits from strong collaboration with end-user partners in Africa and the Middle East, who provide insights on strategies to formulate and communicate early warning indicators to water and food security communities. The additional lead time provided by this system will increase the speed, accuracy, and efficacy of humanitarian disaster relief, helping to save lives and livelihoods.
4 Xu, H.; Yang, R.; Song, J. 2023. Water rights reform and water-saving irrigation: evidence from China. Water Science and Technology, 88(11):2779–2792. [doi: https://doi.org/10.2166/wst.2023.385]
Water rights ; Reforms ; Water conservation ; Drip irrigation ; Trickle irrigation ; Agricultural production ; Agricultural water use ; Water productivity ; Water extraction ; Grain crops ; Cash crops ; Water scarcity ; Water resources ; Land area ; Cultivated land ; Precipitation / China
(Location: IWMI HQ Call no: e-copy only Record No: H052441)
https://iwaponline.com/wst/article-pdf/88/11/2779/1340235/wst088112779.pdf
https://vlibrary.iwmi.org/pdf/H052441.pdf
https://vlibrary.iwmi.org/pdf/H052441.pdf
(0.60 MB) (612 KB)
As a market-based water resource management, the water rights reform (WRR) will allocate water rights to water users and allow water users to trade water rights, which can realize the reallocation across water users. In this context, the adoption of water-saving irrigation (WSI) is an important technical form to adapt to the reform. Based on this, this paper studies the impacts of the WRR on WSI using the difference-in-differences (DID) strategy. The results show that the WRR could increase the land area for WSI by an average of 13.63%. The WRR could promote the expansion of high-efficiency irrigation mainly because the WRR could promote the expansion of spray and drip irrigation areas, and micro-irrigation land areas, which are high-efficiency water-saving irrigation technologies. In addition, the WRR also could improve agricultural production by increasing agricultural water productivity and planting area (including the sown area of grain crops and cash crops), but the WRR does not reduce agricultural water extraction. Therefore, the WRR could increase agricultural production without increasing agricultural water extraction.
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