Your search found 13 records
1 Silva, E. I. L.. 1996. Water quality of Sri Lanka: A review on twelve water bodies. Kandy, Sri Lanka: IFS. vii, 141p.
Water resources ; Water quality ; Rivers ; Estuaries ; Lagoons ; Reservoirs ; Tanks ; Canals ; Watersheds ; Land use ; River basins ; Water pollution / Sri Lanka / Kelani River / Negombo Lagoon / Bolgoda Lake / Koggala Lagoon / Kotmale Reservoir / Kala Wewa / Rajangana Tank / Kandy Lake / Meda Ela / Hamilton Canal / Hikkaduwa Marine Sanctuary
(Location: IWMI-HQ Call no: 333.91 G744 SIL Record No: H019963)
2 Silva, E. I. L.; Namaratne, S. Y.; Weerasooriya, S. V. R.; Manuweera, L. 1996. Water analysis: User-friendly field/laboratory manual. Kandy, Sri Lanka: IFS. Department of Environmental Sciences. v, 193p.
Water quality ; Monitoring ; Analytical methods ; Statistical analysis ; Measuring instruments ; Quality control ; Alkalinity / Sri Lanka
(Location: IWMI-HQ Call no: 628.1 G744 SIL Record No: H019964)
3 Silva, E. I. L.. (Ed.) 1993. Environmental pollution: Denaturing the quality of nature. Kandy, Sri Lanka: IFS. 86p.
Environmental degradation ; Energy resources ; Water quality ; Water pollution ; Groundwater ; Ecology / Sri Lanka
(Location: IWMI-HQ Call no: 363.7 G744 SIL Record No: H022343)
Papers presented at the seminar held on 9 October 1993 at the Institute of Fundamental Studies.
4 Sharaff, F. F.; Silva, E. I. L.; Samaradiwakara, S. R. M. S.; Kangara, K. M. W. S. B.; Karunathilake, K. M. B. C.; Weerasinghe, W. M. D. 2004. Trophic evolution in Kandy Lake: An outcome of urban development, land use and demographic change. In Herath, S.; Pathirana, A.; Weerakoon, S. B. (Eds.). Proceedings of the International Conference on Sustainable Water Resources Management in the Changing Environment of the Monsoon Region. Bandaranaika Memorial International Conference Hall, Colombo, Sri Lanka, 17-19 November 2004. Vol.II. Colombo, Sri Lanka: National Water Resources Secretariat. pp.506-513.
Lakes ; Watersheds ; Water pollution ; Water quality ; Land use ; Water management / Sri Lanka / Kandy Lake
(Location: IWMI-HQ Call no: 333.91 G000 HER Record No: H039537)
5 Silva, E. I. L.. 2004. “Let not a single drop of rain water be allowed to reach the sea without benefiting Mankind” – Myth or reality? In Herath, S.; Pathirana, A.; Weerakoon, S. B. (Eds.). Proceedings of the International Conference on Sustainable Water Resources Management in the Changing Environment of the Monsoon Region. Bandaranaika Memorial International Conference Hall, Colombo, Sri Lanka, 17-19 November 2004. Vol.II. Colombo, Sri Lanka: National Water Resources Secretariat. pp.686-696.
Water resources development ; History ; Development projects ; Water balance ; Reservoirs ; Sedimentation ; Reservoirs ; Plankton blooms ; Fish ; Biodiversity / Sri Lanka / Mahaweli Project
(Location: IWMI-HQ Call no: 333.91 G000 HER Record No: H039561)
6 Silva, E. I. L.. 2004. Phytoplankton characteristics, trophic evolution, and nutrient dynamics in an urban eutrophic lake: Kandy Lake in Sri Lanka. In Reddy, M. V. (Ed.). Restoration and management of tropical eutrophic lakes. Enfield, NH, USA: Science Publishers, Inc. pp.227-270.
Lakes ; Ecosystems ; Phytoplankton ; Water pollution ; Water quality ; Nutrients / Sri Lanka / Kandy Lake
(Location: IWMI HQ Call no: P 7998 Record No: H041121)
7 Silva, E. I. L.. 2006. Ecology of phytoplankton in tropical waters: introduction to the topic and ecosystem changes from Sri Lanka. Asian Journal of Water, Environment and Pollution, 4(1): 25-35.
(Location: IWMI HQ Record No: H041122)
Some aspects of ecology of phytoplankton in four distinct types of standing water bodies were Diagnosed using the outcome of a long-term study conducted in Sri Lankan reservoirs on species composition and richness, temporal and seasonal patterns in relation to environmental variables. Nearly 150 taxa belonging to nine taxonomic groups were identified of which some have been reported in previous studies. The numerical analysis of the overall species lists shows that the taxonomic composition, species richness and sequential periodicity varies largely among different types of environments with higher resemblance for water bodies located at comparable eco-regions with similar morphological, hydraulic, hydro-chemical and trophic features. Relative abundance and species spectrum can be used to classify the water bodies into oligo-mesotrophic (large and deep canyon-shaped, newly built hydropower reservoirs), meso-eutrophic (dry zone irrigation tanks) and eutrophic-heterotrophic (urban water bodies) which show distinct annual trophic alteration influenced by monsoonal rainfall. Unlike in temperate regions, they exhibit non-rhythmic successional episodes, some prefer specific chemical environment and some taxa become more stable when essential nutrients are in surplus. The numerical dominance or biomass is not regulated by grazing but a large amount of phytoplankton biomass is lost during water release from the euphotic zone.
8 Jayatissa, L. P.; Silva, E. I. L.; McElhiney, J.; Lawton, L. A. 2006. Occurrence of toxigenic cyanobacterial blooms in freshwaters of Sri Lanka. Systematic and Applied Microbiology, 29: 156-164.
Phytoplankton ; Cyanobacteria ; Eutrophication ; Water quality ; Water pollution ; Reservoirs ; Tanks ; Irrigation water / Sri Lanka / Tissawewa / Colombo Lake / Kandy Lake / Situlpawwa Lake
(Location: IWMI HQ Call no: P 7999 Record No: H041123)
A previous pioneering study of freshwater bodies in Sri Lanka revealed the presence of toxic cyanobacteria in three out of four water bodies tested. It was therefore important to perform a more detailed investigation into the presence of cyanobacteria and their toxins throughout Sri Lanka. The country has a long history of well-planned water management with the agricultural economy and drinking water supply still dependent on thousands of man-made tanks. Seventeen reservoirs from different user categories and different climatic zones were selected to study variations in phytoplankton communities with relation to major nutrients, with particular emphasis on cyanobacteria. The study was carried out during a two-year period and heavy growths or blooms of cyanobacteria observed during the study period were tested for microcystins. The results clearly categorised the 17 reservoirs into four groups parallel to the classification based on the user categories of water bodies. Biomass of total phytoplankton, the abundance of cyanobacteria, the dominance of Microcystis spp. and concentration of nitrate (N) and total phosphorous (P) were the lowest in drinking water bodies and the highest in aesthetic water bodies. Irrigation water bodies showed the second lowest values for phytoplankton biomass, and concentration of N and P, while hydropower reservoirs showed the second highest values for the same parameters. The fraction of cyanobacteria in irrigation waters was higher than that in hydropower reservoirs, but surprisingly the dominance of Microcystis spp. was reversed. Possible reasons for these variations are discussed. More than half of the bloom material tested contained microcystins up to 81microgl(-1). Our findings indicate the potential for high-risk situations due to toxigenic cyanobacterial blooms in susceptible freshwaters of Sri Lanka.
9 Silva, E. I. L.. 2003. Emergence of a Microcystis bloom in an urban water body, Kandy Lake, Sri Lanka. Current Science, 85(6): 723-725.
(Location: IWMI HQ Call no: P 8000 Record No: H041124)
10 Silva, E. I. L.; Manuweera, L. 2004. Surface and rainwater chemistry in Sri Lanka: a risk of acidification. Asian Journal of Water, Environment and Pollution, 1(1-2): 79-86.
(Location: IWMI HQ Call no: P 8001 Record No: H041125)
11 Silva, E. I. L.. 2004. Quality of irrigation water in Sri Lanka: status and trends. Asian Journal of Water, Environment and Pollution, 1(1): 5-12.
(Location: IWMI HQ Call no: P 8002 Record No: H041126)
12 Silva, E. I. L.; Katupotha, J.; Amarasinghe, O.; Manthrithilake, Herath; Ariyaratne, Ranjith. 2013. Lagoons of Sri Lanka: from the origins to the present. Colombo, Sri Lanka: International Water Management Institute (IWMI). 116p. [doi: https://doi.org/10.5337/2013.215]
Coastal lagoons ; Hydrology ; Hydrography ; Ecosystems ; Biodiversity ; Fauna ; Mangroves ; Marshes ; Salinity ; Geomorphology ; Species ; Poverty ; Fisheries ; Governance ; Institutions ; Legislation / Sri Lanka
(Location: IWMI HQ Call no: IWMI Record No: H046256)
(1.50 MB)
13 Silva, E. I. L.; Manthrithilake, Herath; Pitigala, D.; Silva, E. N. S. 2014. Environmental flow in Sri Lanka: ancient anicuts versus modern dams. Sri Lanka Journal of Aquatic Sciences, 19:3-14. [doi: https://doi.org/10.4038/sljas.v19i0.7447]
Environmental flows ; River basin development ; Stream flow ; Irrigation systems ; Hydraulic structures ; Traditional technology ; Dams ; Weirs ; Reservoirs ; Water power ; Tributaries ; Diversion ; Modernization ; History / Sri Lanka / Mahaweli River Basin / Walawe River Basin / Kala Oya Basin / Yan Oya Basin / Maduru Oya Basin / Polgolla Dam / Neela Bemma Dam
(Location: IWMI HQ Call no: e-copy only Record No: H048033)
(0.65 MB) (660 KB)
Environmental flow describes the stream flow (quantity and regime) required to sustain upstream and downstream habitats, riparian vegetation, human livelihoods and wildlife. When natural rivers or tributaries are held back by weirs, anicuts, barrages or dams, for a variety of purposes such as diversion for irrigation, hydropower generation or flood control often the downstream flow requirement is ignored or neglected. Although there is no universally accepted definition, convention or law on environmental flow, it has been now recognized that environmental flow is essential for sustainability of riparian ecosystem and their services, which are essential for our own existence, livelihoods and many more. This paper looks at physical structures constructed across rivers and tributaries in Sri Lanka since ancient times to date (including mini-hydro power stations) with a view to understand whether simple ancient wisdoms are more appropriate than modern structures for nature conservation. There are tangible evidence to defend that the ancient anicuts known as “amuna” surged sufficient water in tributaries and rivers, to sustain the environment than modern engineering works which has created dead river beds immediately downstream in many streams and rivers.
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