Your search found 41 records
1 Amarnath, Giriraj; Alahacoon, Niranga; Sharma, Bharat; Smakhtin, Vladimir. 2013. Manual of the Training on Development of Flood Forecasting System for Gash Basin using Hydrological Model System, held at the Hydraulic Research Station (HRS), Kassala, Sudan, 27-29 August 2013. Colombo, Sri Lanka: International Water Management Institute (IWMI). 83p.
Training materials ; Remote sensing ; GIS ; Flooding ; Forecasting ; River basins ; Models ; Spate irrigation ; Watersheds ; Rain ; Flow discharge ; Computer applications ; Data / Sudan / Gash Basin
(Location: IWMI HQ Call no: e-copy only Record No: H046101)
(17.26 MB)
2 Amarnath, Giriraj; Alahacoon, Niranga; Inada, Yoshiaki. 2014. Inundations in the Sri Lanka: monitoring and analysis from MODIS [Moderate Resolution Imaging Spectroradiometer] and ALOS [Advanced Land Observing Satellite] instrument. 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.476-478.
Flooding ; Rain ; Satellite imagery ; Satellite observation ; Land cover ; GIS ; Remote sensing ; Case studies / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H046625)
(0.46 MB)
Sri Lanka is facing severe flood events during monsoon rainfall in each year all over the country. The rapid development of remote sensing and widely available satellite images can be used effectively to map the flood inundation in past years. This study is focused on the mapping of flood inundation together with flood recurrent based on both optical (MODIS) and microwave (ALOS/PALSAR) satellite images. In the first stage MODIS images with spatial resolution of 500m and temporal interval of eight day was used to map flood recurrent areas for risk assessment using images from 2000 to 2011. In the second state 16 satellite images from ALOS PALSAR images between 2006 and 2011 was analyzed by using pixel threshold value to map the flooded and non-flooded areas. The flood recurrent products from both MODIS and PALSAR images were generated to represent the repetition of flood inundated areas. The analysis of the results indicated that the PALSAR image based flood inundation mapping is much accurate and useful in the context of spatial variability than the temporal variability. The accurate land-cover map is also important to assess the flood damages and evaluate the future development and the cultivation planning. But there is no such an accurate and detailed land-cove map available for Sri Lanka to assess the flood damages. Thus, this study was focused on the preparation of land-cover map with GIS and RS approach. The land-cover classification was carried out by image fusion of optical (LANDSAT) and microwave (ALOS/PALSAR) under High Pass Filtering (HPF) technique. Unsupervised image classification method was used to classify the fused image in to different land-cover classes. Accuracy assessment of land-cover classification was conducted using existing ground truth information and Google Earth with as resulted in the overall accuracy as 71.16% and the Kappa statistics as 62.83%.
3 Amarnath, Giriraj; Rajah, Ameer; Alahacoon, Niranga; Inada, Yoshiaki; Inoue, R.; Aggarwal, Pramod. 2014. Potential of satellite data in catastrophic flood risk mapping and assessment: case studies from Asia and Africa. In Stal, M.; Sigrist, D.; Ammann, W. (Eds.). Proceedings of the 5th International Disaster and Risk Conference on Integrative Risk Management - The Role of Science, Technology and Practice, Davos, Switzerland, 24 - 28 August 2014. Extended Abstracts. Davos, Switzerland: Global Risk Forum GRF Davos. pp.52-55. pp.52-55.
Natural disasters ; Flooding ; Risk assessment ; Mapping ; Satellite imagery ; Case studies / Asia / Africa / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H046630)
(1.02 MB)
Over last decades, we have witnessed an upward global trend in natural disaster occurrence. Hydrological and meteorological disasters are the main contributors to this pattern. In 2011, hydrological disaster, such as floods and wet mass movements, represented 52% of the overall disaster reported, causing 139.8 million victims and more than U.S. $70 billion in damages. Remote sensing from space plays an important role in flood mapping and flood risk assessment. Satellite images acquired in both optical and microwave range of electro-magnetic emissions are utilized for solving many problems related to flood risk management. This paper presents two different research activities (1) flood detection algorithm which uses vegetation and water indices (NDVI, EVI, LSWI, DVEL) at a spatial resolution of 500m and time period 2000 – 2013 using MODIS Terra/Aqua and JAXA PALSAR satellite to spatially and temporally quantify flood inundation extent at a continental scale in South Asia, Southeast Asia and Nigeria in the context of emergency response and (2) blending satellite data and RADAR (Rapid Agriculture Disaster Assessment Routine) tool for rapid flood damage assessment in agriculture with a case study in Sri Lanka. The results of the present study will provide valuable information to flood policy makers and flood disaster researchers.
4 Amarnath, Giriraj; Inada, Yoshiaki; Ghosh, Surajit; Yakob, Umer; Alahacoon, Niranga; Kota, Harada; Inoue, Ryosuke; Schlaffer, S. 2014. Earth observation technologies for flood-risk mapping, modeling and management. Training manual prepared for Capacity Building Workshop on Earth Observation Technologies for Flood-risk mapping, Modeling and Management, Peradeniya, Sri Lanka, 18-21 November 2014. Peradeniya, Sri Lanka: University of Peradeniya. Postgraduate Institute of Science. 170p.
Earth observation satellites ; Satellite imagery ; Radar satellite ; Early warning systems ; Flood control ; Risk management ; Models ; Capacity building ; Rain ; Runoff ; Climate change ; Impact assessment ; Hydraulics ; Case studies ; Training materials / Sri Lanka / Thailand / Mundeni Aru Basin
(Location: IWMI HQ Call no: IWMI Record No: H046777)
(11.97 MB)
5 Amarnath, Giriraj; Umer, Yakob Mohammed; Alahacoon, Niranga; Inada, Yoshiaki. 2015. Modelling the flood-risk extent using LISFLOOD-FP in a complex watershed: case study of Mundeni Aru River Basin, Sri Lanka. Proceedings of the International Association of Hydrological Sciences, 370:131-138. [doi: https://doi.org/10.5194/piahs-370-131-2015]
Flood control ; Watersheds ; River basins ; Models ; Satellite observation ; Radar satellite ; Natural disasters ; Risk management ; Hydraulics ; Rain ; Case studies / Sri Lanka / Mundeni Aru River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047060)
http://www.proc-iahs.net/370/131/2015/piahs-370-131-2015.pdf
https://vlibrary.iwmi.org/pdf/H047060.pdf
https://vlibrary.iwmi.org/pdf/H047060.pdf
(1.04 MB) (1.04 MB)
Flood management is adopting a more risk-based approach, whereby flood risk is the product of the probability and consequences of flooding. Two-dimensional flood inundation modeling is a widely used tool to aid flood-risk management. The aim of this study is to develop a flood inundation model that uses historical flow data to produce flood-risk maps, which will help to identify flood protection measures in the rural areas of Sri Lanka. The LISFLOOD-FP model was developed at the basin scale using available historical data, and also through coupling with a hydrological modelling system, to map the inundation extent and depth. Results from the flood inundation model were evaluated using Synthetic Aperture Radar (SAR) images to assess product accuracy. The impacts of flooding on agriculture and livelihoods were analyzed to assess the flood risks. It was identified that most of the areas under paddy cultivation that were located near the middle and downstream part of the river basin are more susceptible to flood risks. This paper also proposes potential countermeasures for future natural disasters to prevent and mitigate possible damages.
6 Amarnath, Giriraj; Pandey, Rajesh; Alahacoon, Niranga. 2015. Earth observation technologies for flood-risk mapping and forecast rating curve for flood recession agriculture in Nigeria. Training manual prepared for Capacity building workshop on Earth Observation Technologies for Flood-risk mapping and Forecast rating curve for Flood recession Agriculture in Nigeria, Abuja, Nigeria, 5-7 May 2015. Colombo, Sri Lanka: International Water Management Institute (IWMI). 84p.
Earth observation satellites ; Satellite imagery ; Satellite surveys ; Radar satellite ; Flood control ; Mapping ; Risk management ; Weather forecasting ; Hydrology ; Models ; Computer applications ; Remote sensing ; Water levels ; Flow discharge ; Capacity building ; Training materials ; Case studies / Nigeria / Niger River / Benue River
(Location: IWMI HQ Call no: IWMI Record No: H047076)
(0.33 MB)
7 Amarnath, Giriraj; Alahacoon, Niranga; Gismalla, Y.; Mohammed, Y.; Sharma, Bharat R.; Smakhtin, Vladimir. 2016. Increasing early warning lead time through improved transboundary flood forecasting in the Gash River Basin, Horn of Africa. In Adams, T. E. III; Pagano, T. C. (Eds.). Flood forecasting: a global perspective. London, UK: Academic Press. pp.183-200.
International waters ; Weather forecasting ; Flooding ; Early warning systems ; Rainfall-runoff relationships ; Hydrology ; Hydrometeorology ; Topography ; Models ; Calibration ; River basins ; Flow discharge ; Hydrography ; Catchment areas ; Satellite observation ; Spatial database / Horn of Africa / Sudan / Ethiopia / Eritrea / Gash River Basin / Kassala
(Location: IWMI HQ Call no: e-copy only Record No: H047695)
(1.09 MB)
8 Pani, Peejush; Alahacoon, Niranga; Amarnath, Giriraj; Bharani, Gurminder; Mondal, S.; Jeganathan, C. 2016. Comparison of SPI [Standardized Precipitation Index] and IDSI [Integrated Drought Severity Index] applicability for agriculture drought monitoring in Sri Lanka. Paper presented at the 37th Asian Conference on Remote Sensing (ACRS): Promoting Spatial Data Infrastructure for Sustainable Economic Development, Colombo, Sri Lanka, 17-21 October 2016. 8p.
Precipitation ; Drought ; Monitoring ; Agriculture ; Climate change ; Meteorology ; Remote sensing ; Vegetation ; Rain ; Temperature ; Soil moisture ; Spatial distribution ; Statistical analysis / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H047942)
Increasing frequency of drought events coupled uncertainty imparted by climate change pose grave threat to agriculture and thereby overall food security. This is especially true in South Asian region where world’s largest concentration of people depends on agriculture for their livelihood. Indices derived from remote sensing datasets signifying different bio-physical aspects are increasingly used for operational drought monitoring. This study focuses on evaluating a newly created index for agricultural drought referred as Integrated Drought Severity Index (IDSI) in comparison with the traditional Standardized Precipitation Index (SPI) primarily representing precipitation condition to delineate drought using custom created ArcGIS toolbox for a period of fourteen years (2001-2014) in Sri Lanka. SPI created using remotely sensed PERSIANN precipitation dataset was compared with the IDSI created using hybrid datasets. IDSI is created based on seamless mosaic of remotely sensed multi-sensor data that takes vegetation (computed from MODIS data product MOD09A1), temperature (MOD11A2) and precipitation (TRMM & GPM) status into consideration. The comparative study was made to assess the efficiency of newly created index and ArcGIS toolbox techniques for near real-time monitoring of spatio-temporal extent of agricultural drought. The result showed significant correlation of 0.85 between the two indices signifying the potential of using IDSI that integrates the response of agriculture drought variables (vegetation, rainfall, temperature and soil moisture) in monitoring shortterm drought and application in risk reduction measures.
9 Alahacoon, Niranga; Pani, Peejush; Matheswaran, Karthikeyan; Samansiri, S.; Amarnath, Giriraj. 2016. Rapid emergency response mapping for the 2016 floods in Kelani river basin, Sri Lanka. Paper presented at the 37th Asian Conference on Remote Sensing (ACRS): Promoting Spatial Data Infrastructure for Sustainable Economic Development, Colombo, Sri Lanka, 17-21 October 2016. 9p.
Natural disasters ; Disaster preparedness ; Flooding ; Emergency relief ; River basins ; Radar satellite ; Satellite imagery ; Landslides ; Remote sensing / Sri Lanka / Kelani River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047943)
Beginning on 14 May 2016, a low pressure area over the Bay of Bengal caused torrential rain to fall across Sri Lanka. Some locations saw over 350 mm (13.77 inches) of rain fall in 24 hours. Floods and landslides have caused havoc in as many as 19 districts of the country, including around Colombo, causing floods and landslides which affected half a million people with causality reported over 100 and estimated economic losses closer to $2billion. In recent years, due to an increasing number in the frequency and intensity of extreme meteorological events potentially related to climate change, a growing attention has been paid to the operational use of satellite remote sensing applied to emergency response and relief measures. This is mainly due to the large and timely availability of different types of remotely sensed data as well as geospatial information acquired in the field which may be potentially exploited in the different phases of the disaster management cycle. IWMI jointly with Disaster Management Centre (DMC), Sri Lanka activated disaster charter with Sentinel Asia and escalated International Disaster Charter to access satellite images during the crisis response phase to support government agencies in relief and rescue measures. A total of 13 satellite images both microwave and optical datasets (ALOS-2, Sentinel-1, RISAT-1, RADARSAT-2, TerraSAR-X, FORMOSAT, Landsat-8) were provided by various space agencies to generate flood situation maps on a daily basis. The emergency flood situation maps were regularly shared to national and international organizations within 3-4 hours after the post-event image is acquired by the space agencies to support in relief measures. The derived flood maps were overlaid with local administrative division to give specific information on the priority area to the DMC and Air Force authorities to focus relief measures. These rapid response maps can further be used for postdisaster relief policy and damage assessment.
10 Amarnath, Giriraj; Alahacoon, Niranga; Smakhtin, V.; Aggarwal, P. 2017. Mapping multiple climate-related hazards in South Asia. Colombo, Sri Lanka: International Water Management Institute (IWMI). 41p. (IWMI Research Report 170) [doi: https://doi.org/10.5337/2017.207]
Climate change adaptation ; Natural disasters ; Weather hazards ; Mapping ; Flooding ; Drought ; Rain ; Erosion ; Temperature ; Sea level ; Water levels ; Coastal area ; Sloping land ; Tsunamis ; Agriculture ; Impact assessment ; Population ; Risk management ; Socioeconomic environment ; Land cover / South Asia / India / Bangladesh / Sri Lanka / Pakistan / Nepal / Bhutan
(Location: IWMI HQ Call no: IWMI Record No: H048140)
(6.07 MB)
This Research Report presents the first comprehensive overview of the multiple climate hazard risks, and the proposed key issues and challenges facing the South Asian region. This report suggests methods for mapping such risks and estimating their impacts on people and agriculture in South Asia. Regional, country-wise and sub-national assessment of five climate-related risks – floods, droughts, extreme rainfall, extreme temperature and sea-level rise – is carried out. The approach involves overlaying climate hazard, sensitivity and adaptive capacity maps, and follows the vulnerability assessment framework of the Intergovernmental Panel on Climate Change (IPCC). A combined index based on hazard, exposure and adaptive capacity is introduced to identify areas susceptible to extreme risk. There is a lack of a systematic and comprehensive risk assessment capturing multiple climate hazards for the entire South Asian region and the need for a common framework for risk assessment. While this approach is well grounded in theories and integration of various spatial data including remote sensing data to derive hazard information, there is a clear need for linking additional elements from the ground at a finer scale among various sectors in developing comprehensive risk assessment information for a disaster risk management plan and promoting risk financing strategies.
11 Amarnath, Giriraj; Matheswaran, Karthikeyan; Pandey, Pooja; Alahacoon, Niranga; Yoshimoto, Shuhei. 2017. Flood mapping tools for disaster preparedness and emergency response using satellite data and hydrodynamic models: a case study of Bagmathi Basin, India. Proceedings of the National Academy of Sciences India Section A-Physical Sciences, 87(4):941-950. [doi: https://doi.org/10.1007/s40010-017-0461-7]
Floodplains ; Flooding ; Disaster preparedness ; Satellite observation ; Satellite imagery ; Hydrodynamics ; Models ; Mapping ; Emergencies ; Rainfall-runoff relationships ; River basins ; Case studies / India / Bagmathi Basin
(Location: IWMI HQ Call no: e-copy only Record No: H048410)
Northern Bihar is one of the major flood prone region in India affecting thousands of human lives and livelihoods during the recurrent floods occurring due to the monsoonal rains. While it is impossible to prevent the occurrence of extreme flood events, disaster planning can help in mitigating its detrimental effects. Monitoring flood extent using satellite observations just after the flood disasters is a core component of rapid emergency response process, which enables the emergency rescue teams to prioritize their efforts in critical areas to save lives and protect health, in addition to providing near real-time flooding information to the decision makers and planners. The main objective of this study is to demonstrate the utility of less data intensive, but equally robust hydrodynamic models to develop flood extent maps in conjunction with freely available remote sensing imageries at different scales. MODIS TERRA satellite data was used to map flood extent from 2001 to 2016 for entire Bihar. Two hydraulic models namely FLDPLN and RRI applied for the Bagmathi basin to evaluate our objectives. Both these models are of varying complexity but generate flood extent patterns with minimum amount of input data. The proposed approach is suited for mapping flood extents to provide an input information in near real time (h) when there is no availability to detailed hydraulic models and satellite datasets. Flood inundation extents from FLDPLN and RRI models were validated with Landsat-7 and MODIS TERRA derived flood extents for model performance. The results show acceptable spatial agreement between model predicted and Landsat-7 observed flood extents, denoting the utility of these tools for flood mapping application in data scarce environments.
12 Alahacoon, Niranga; Matheswaran, Karthikeyan; Pani, Peejush; Amarnath, Giriraj. 2018. A decadal historical satellite data and rainfall trend analysis (2001–2016) for flood hazard mapping in Sri Lanka. Remote Sensing, 10(3):1-18. [doi: https://doi.org/10.3390/rs10030448]
Satellite imagery ; Satellite observation ; Radar satellite ; Rain ; Mapping ; Flooding ; Flood control ; Natural disasters ; Economic situation ; River basins ; Monsoon climate ; Risk management ; Catchment areas / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H048581)
(10.8 MB)
Critical information on a flood-affected area is needed in a short time frame to initiate rapid response operations and develop long-term flood management strategies. This study combined rainfall trend analysis using Asian Precipitation—Highly Resolved Observational Data Integration towards Evaluation of Water Resources (APHRODITE) gridded rainfall data with flood maps derived from Synthetic Aperture Radar (SAR) and multispectral satellite to arrive at holistic spatio-temporal patterns of floods in Sri Lanka. Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) data were used to map flood extents for emergency relief operations while eight-day Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data for the time period from 2001 to 2016 were used to map long term flood-affected areas. The inundation maps produced for rapid response were published within three hours upon the availability of satellite imagery in web platforms, with the aim of supporting a wide range of stakeholders in emergency response and flood relief operations. The aggregated time series of flood extents mapped using MODIS data were used to develop a flood occurrence map (2001–2016) for Sri Lanka. Flood hotpots identified using both optical and synthetic aperture average of 325 km2 for the years 2006–2015 and exceptional flooding in 2016 with inundation extent of approximately 1400 km2. The time series rainfall data explains increasing trend in the extreme rainfall indices with similar observation derived from satellite imagery. The results demonstrate the feasibility of using multi-sensor flood mapping approaches, which will aid Disaster Management Center (DMC) and other multi-lateral agencies involved in managing rapid response operations and preparing mitigation measures.
13 Amarnath, Giriraj; Simons, G. W. H.; Alahacoon, Niranga; Smakhtin, V.; Sharma, Bharat; Gismalla, Y.; Mohammed, Y.; Andrie, M. C. M. 2018. Using smart ICT to provide weather and water information to smallholders in Africa: the case of the Gash River Basin, Sudan. Climate Risk Management, 22:52-66. [doi: https://doi.org/10.1016/j.crm.2018.10.001]
Irrigation methods ; Flood irrigation ; Flooded land ; Remote sensing ; Geographical information systems ; Weather forecasting ; Weather data ; Smallholders ; River basins ; Information and Communication Technologies (icts) ; Crop production ; Crop yield ; Monitoring ; Water use ; Biomass ; Farmers ; Rain ; Case studies / Africa / Sudan / Gash River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H048976)
In the Gash Delta of Eastern Sudan, spate irrigation (flood-recession farming) contributes substantially to rural livelihoods by providing better yields than rainfed dryland farming. However, spate irrigation farmers are challenged by the unpredictability of flooding. In recent decades, the number of farmers practicing spate irrigation has decreased, due to varying rainfall intensity and frequency, insufficient infrastructure and farmers’ limited capacity to manage such variations. One solution that may help farmers face such challenges is for them to access real-time water-related information by using smart Information and Communication a Technology (ICT). This paper shows how integrating remote sensing, Geographical Information Systems (GIS), flood-forecasting models and communication platforms can, in near real time, alert smallholder farmers and relevant government departments about incoming floods, using the Gash basin of Sudan as an example. The Ministry of Water Resources of Sudan used the findings of this study to transform farmers’ responses to flood arrival from being ‘reactive’, to planning for the flood event. Intensive on-site and institutional efforts to build the capacity of farmers, farmer organizations, development departments and officers of the Ministry helped to develop the initiative from simply sending ‘emergency alerts’ to enabling stakeholders to visually see the flood event unfolding in the region and to plan accordingly for storing water, operating spate-irrigation systems and undertaking cropping activities. The research, initially conducted on a 60 × 60 km site, was later extended to the entire Gash basin. The paper outlines how to develop tools that can monitor plot-specific information from satellite measurements, and supply detailed and specific information on crops, rather than providing very general statements on crop growth. Farmers are able to use such tools to optimize their farm profits by providing water to their crops in the right place, at the right time and in the right quantity. Finally, the work demonstrates the high potential of combining technology, namely remote sensing data and simple a agro-meteorological model with limited parameters, for large-scale monitoring of spate irrigation systems and information sharing to advise farmers as to how to apply this information to their managerial decisions.
14 Amarnath, Giriraj; Pani, Peejush; Alahacoon, Niranga; Chockalingam, J.; Mondal, S.; Matheswaran, K.; Sikka, Alok; Rao, K. V.; Smakhtin, Vladimir. 2019. Development of a system for drought monitoring and assessment in South Asia. In Mapedza, Everisto; Tsegai, D.; Bruntrup, M.; McLeman, R. (Eds.). Drought challenges: policy options for developing countries. Amsterdam, Netherlands: Elsevier. pp.133-163. (Current Directions in Water Scarcity Research Volume 2) [doi: https://doi.org/10.1016/B978-0-12-814820-4.00010-9]
Drought ; Monitoring ; Assessment ; Temperature ; Rain ; Precipitation ; Satellite observation ; Weather forecasting ; Land use ; Land cover ; Remote sensing ; Vegetation index ; Agriculture ; Crop yield / South Asia / India / Sri Lanka / Pakistan
(Location: IWMI HQ Call no: IWMI Record No: H049369)
(15.10 MB)
15 Amarasinghe, Upali; Amarnath, Giriraj; Alahacoon, Niranga; Ghosh, Surajit. 2020. How do floods and drought impact economic growth and human development at the sub-national level in India? Climate, 8(11):123. (Special issue: Climate Change and Water-Related Agricultural Risks) [doi: https://doi.org/10.3390/cli8110123]
Flooding ; Drought ; Natural disasters ; Economic growth ; Gross national product ; Climate change adaptation ; Mitigation ; Monsoon climate ; Rain ; Trends ; Satellite observation ; Estimation ; River basins ; Groundwater recharge ; Investment ; Population / India
(Location: IWMI HQ Call no: e-copy only Record No: H050046)
(3.66 MB) (3.66 MB)
This paper tries to shift the focus of research on the impact of natural disasters on economic growth from global and national levels to sub-national levels. Inadequate sub-national level information is a significant lacuna for planning spatially targeted climate change adaptation investments. A fixed-effect panel regression analyses of 19 states from 2001 to 2015 assess the impacts of exposure to floods and droughts on the growth of gross state domestic product (GSDP) and human development index (HDI) in India. The flood and drought exposure are estimated using satellite data. The 19 states comprise 95% of the population and contribute 93% to the national GDP. The results show that floods indeed expose a large area, but droughts have the most significant impacts at the sub-national level. The most affected GSDPs are in the non-agriculture sectors, positively by the floods and negatively by droughts. No significant influence on human development may be due to substantial investment on mitigation of flood and drought impacts and their influence on better income, health, and education conditions. Because some Indian states still have a large geographical area, profiling disasters impacts at even smaller sub-national units such as districts can lead to effective targeted mitigation and adaptation activities, reduce shocks, and accelerate income growth and human development.
16 Amarasinghe, Upali A.; Amarnath, Giriraj; Alahacoon, Niranga. 2020. Vulnerable hot spots to water and agricultural risk in Sri Lanka. NeelaHaritha: The Climate Change Magazine of Sri Lanka, 3:1-10.
Climate change adaptation ; Vulnerability ; Indicators ; Water security ; Agricultural sector ; River basins ; Risk assessment ; Drought ; Flooding ; Rain ; Runoff ; Policies ; Socioeconomic aspects / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H050176)
http://www.climatechange.lk/CCS2020/NeelaHaritha%20Vol%20III.pdf#page=8
https://vlibrary.iwmi.org/pdf/H050176.pdf
https://vlibrary.iwmi.org/pdf/H050176.pdf
(0.68 MB) (87.4 MB)
17 Alahacoon, Niranga; Edirisinghe, M. 2021. Spatial variability of rainfall trends in Sri Lanka from 1989 to 2019 as an indication of climate change. ISPRS International Journal of Geo-Information, 10(2):84. [doi: https://doi.org/10.3390/ijgi10020084]
Rainfall patterns ; Trends ; Climate change ; Spatial variation ; Weather hazards ; Climatic zones ; Natural disasters ; Precipitation ; Flooding ; Monsoons ; Drought ; Arid zones ; Semiarid zones ; Geographical information systems / Sri Lanka
(Location: IWMI HQ Call no: e-copy only Record No: H050312)
(3.82 MB) (3.82 MB)
Analysis of long-term rainfall trends provides a wealth of information on effective crop planning and water resource management, and a better understanding of climate variability over time. This study reveals the spatial variability of rainfall trends in Sri Lanka from 1989 to 2019 as an indication of climate change. The exclusivity of the study is the use of rainfall data that provide spatial variability instead of the traditional location-based approach. Henceforth, daily rainfall data available at Climate Hazards Group InfraRed Precipitation corrected with stations (CHIRPS) data were used for this study. The geographic information system (GIS) is used to perform spatial data analysis on both vector and raster data. Sen’s slope estimator and the Mann–Kendall (M–K) test are used to investigate the trends in annual and seasonal rainfall throughout all districts and climatic zones of Sri Lanka. The most important thing reflected in this study is that there has been a significant increase in annual rainfall from 1989 to 2019 in all climatic zones (wet, dry, intermediate, and Semi-arid) of Sri Lanka. The maximum increase is recorded in the wet zone and the minimum increase is in the semi-arid zone. There could be an increased risk of floods in the southern and western provinces in the future, whereas areas in the eastern and southeastern districts may face severe droughts during the northeastern monsoon. It is advisable to introduce effective drought and flood management and preparedness measures to reduce the respective hazard risk levels.
18 Amarasinghe, Upali A.; Amarnath, Giriraj; Alahacoon, Niranga; Aheeyar, Mohamed; Chandrasekharan, Kiran; Ghosh, Surajit; Nakada, Toru. 2021. Adaptation to climate variability in Sri Lanka: a case study of the Huruluwewa Irrigation System in the Dry Zone. Colombo, Sri Lanka: International Water Management Institute (IWMI). 30p. (IWMI Working Paper 200) [doi: https://doi.org/10.5337/2021.229]
Climate variability ; Climate change adaptation ; Irrigation systems ; Arid zones ; Tank irrigation ; Irrigation canals ; Irrigation management ; Land use ; Cropping patterns ; Water supply ; Water depletion ; Crop production ; Water use efficiency ; Irrigation efficiency ; Water productivity ; Water availability ; Drought ; Rainfall patterns ; Risk ; Resilience ; Water scarcity ; Water management ; Reservoirs ; Water spreading ; Catchment areas ; Water storage ; Groundwater recharge ; Water accounting ; Water policies ; Seasonal cropping ; Diversification ; Crop water use ; Consumptive use ; Farmers ; Farm income ; Remote sensing ; Geographical information systems ; Case studies / Sri Lanka / India / North Central Province / Huruluwewa Irrigation System / Sina Irrigation System
(Location: IWMI HQ Call no: IWMI Record No: H050737)
(7.75 MB)
This paper assesses how the Huruluwewa tank (HWT) irrigation system in the North Central Province of Sri Lanka adapts to climate variability. The lessons learned in the HWT will be helpful for many water-scarce irrigation systems in the country, which bear high climate risks. Recurrent droughts are the bane of agriculture in the Dry Zone, comprising three-fourths of the land area spread over the Northern, North Central and Eastern provinces. In the HWT, the fifteenth largest canal irrigation system in the country, adaptation to climate variability happens on several fronts: changes made by the irrigation management to the water release regime; changes in the cropping patterns practiced by farmers in the command area; and the use of groundwater, which is recharged from rainfall, reservoir storage and canal irrigation, as supplemental irrigation. Such adaptation measures ensure that the available water supply in the reservoir is adequate for 100% cropping intensity over two cropping seasons, even in drought years, and enhances economic water productivity in terms of value per unit of consumptive water use. Moreover, irrigation management should consider groundwater recharge through canal irrigation as a resource, which brings substantial agricultural and economic benefits not only for the command area but also outside the command area. The adaptation patterns implemented in HWT demonstrate how water-scarce irrigation systems can achieve higher economic water productivity, i.e., generate ‘more income per drop’ to enhance climate resilience for people in and outside the canal command areas.
19 Amarnath, Giriraj; Ghosh, Surajit; Alahacoon, Niranga; Nakada, Toru; Rao, K. V.; Sikka, Alok. 2021. Regional drought monitoring for managing water security in South Asia. In Amaratunga, D.; Haigh, R.; Dias, N. (Eds.). Multi-hazard early warning and disaster risks. Selected papers presented at the International Symposium on Multi-Hazard Early Warning and Disaster Risk Reduction, Online Symposium, 14-16 December 2020. Cham, Switzerland: Springer. pp.465-481. [doi: https://doi.org/10.1007/978-3-030-73003-1_32]
Drought ; Monitoring ; Water security ; Water management ; Climate change ; Agriculture ; Crop production ; Precipitation ; Remote sensing ; Case studies / South Asia
(Location: IWMI HQ Call no: e-copy only Record No: H050800)
(0.60 MB)
Drought is the most complex climate-related disaster issue in South Asia and has affected 1.46 billion people with an economic loss of over 7 billion USD in the last 56 years. South Asia is challenged with water, food, and energy security due to growing populations, incomes, resource degradation, and vulnerability to climate change. Monitoring of drought and associated agricultural production deficits using meteorological and agricultural indices is an essential component for drought preparedness. Remote sensing offers near real-time monitoring of drought conditions and IWMI’s has implemented South Asia Drought Monitoring System (SADMS) in 2014 as an online platform for drought early warning and support in drought declaration. This chapter explores the use of composite drought indices implemented in Google Earth Engine (GEE) and evaluates the crop yield variability during drought years. The study provides a rapid overview of drought-prone conditions that could enhance the present capabilities of early warning systems and enable science based policies for addressing water security in the agriculture sector and develop a drought response plan between water supply and demand, significantly increasing the vulnerability of regions to damaging impacts of drought events.
20 Alahacoon, Niranga; Edirisinghe, M.; Simwanda, M.; Perera, E. N. C.; Nyirenda , V. R.; Ranagalage, M. 2022. Rainfall variability and trends over the African continent using TAMSAT data (1983-2020): towards climate change resilience and adaptation. Remote Sensing, 14(1):96. [doi: https://doi.org/10.3390/rs14010096]
Rainfall patterns ; Trends ; Climate change adaptation ; Resilience ; Weather hazards ; Climatic zones ; River basins ; Spatial distribution ; Monsoon climate ; Datasets / Africa
(Location: IWMI HQ Call no: e-copy only Record No: H050897)
(13.40 MB) (13.4 MB)
This study reveals rainfall variability and trends in the African continent using TAMSAT data from 1983 to 2020. In the study, a Mann–Kendall (MK) test and Sen’s slope estimator were used to analyze rainfall trends and their magnitude, respectively, under monthly, seasonal, and annual timeframes as an indication of climate change using different natural and geographical contexts (i.e., sub-regions, climate zones, major river basins, and countries). The study finds that the highest annual rainfall trends were recorded in Rwanda (11.97 mm/year), the Gulf of Guinea (river basin 8.71 mm/year), the tropical rainforest climate zone (8.21 mm/year), and the Central African region (6.84 mm/year), while Mozambique (-0.437 mm/year), the subtropical northern desert (0.80 mm/year), the west coast river basin of South Africa (-0.360 mm/year), and the Northern Africa region (1.07 mm/year) show the lowest annual rainfall trends. There is a statistically significant increase in the rainfall in the countries of Africa’s northern and central regions, while there is no statistically significant change in the countries of the southern and eastern regions. In terms of climate zones, in the tropical northern desert climates, tropical northern peninsulas, and tropical grasslands, there is a significant increase in rainfall over the entire timeframe of the month, season, and year. This implies that increased rainfall will have a positive effect on the food security of the countries in those climatic zones. Since a large percentage of Africa’s agriculture is based only on rainfall (i.e., rain-fed agriculture), increasing trends in rainfall can assist climate resilience and adaptation, while declining rainfall trends can badly affect it. This information can be crucial for decision-makers concerned with effective crop planning and water resource management. The rainfall variability and trend analysis of this study provide important information to decision-makers that need to effectively mitigate drought and flood risk.
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