Symposia & Conferences
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Item Spatial and temporal variations of ground water quality in Kalpitiya peninsula(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Dilshara, R.M.P.; Handapangoda, H.M.A.K.; Swarnathilake, D.S.G.G.C.; Amarasinghe, L.D.; Herath, H.M.I.K.; Udayanga, N.W.B.A.L.Intensive agricultural practices in Kalpitiya have caused excessive usage of fertilizers. The sandy regosol soil and the over irrigation due to the presence of semi-arid climatic conditions in the area have led to nutrient leaching conditions in Kalpitiya. Since 1990s, the groundwater aquifers in Kalpitiya remain contaminated with higher levels of nitrate due to intensive agricultural practices and the current status of groundwater pollution remains poorly studied. Therefore, this study was conducted to evaluate the current status of groundwater pollution in Kalpitiya, with special emphasis on spatial and seasonal variations. Groundwater samples of 50 wells (potable and agricultural) located in five sentinel sites, namely Nawakkadu, Narakkalli, Thalavila, Kandakuli and Kalpitiya town were collected at monthly intervals from November 2018 to March 2020. In addition, the existing land use practices surrounding the respective wells were also recorded. Selected water quality parameters, namely pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), salinity, nitrate and phosphate concentrations were analyzed using standard methods. The General Linear Model (GLM) followed by Tukey’s pairwise comparison was used for statistical analysis. Significant spatial variations (p< 0.05) at 95% level of confidence. EC, nitrate, phosphate and TDS levels in groundwater samples of Nawakkadu, Narakkalli, and Kalpitiya town areas remained above the permissible levels for potable water quality given by the Central Environmental Authority (CEA). Therefore, adequate treatment of groundwater is recommended prior to use for drinking purposes.Item Management of coastal resources: Lessons learnt from two coastal communities occupying the west coast of Sri Lanka(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Kodituwakku, K.A.R.K.; Wazir, S.R.; Aththanayake, A.M.H.L.; Silva, T.M.S.D.G.; Malshani, E.M.S.; Partheepan, K.; Thevendran, K.; Udayanga, N.W.B.A.L.; Sumanapala, A.P.; Jayanga, B.H.N.; Chandrasekara, W.U.The livelihood of the coastal communities is mostly dependent upon the natural coastal resources. Questionnaire based field surveys were carried out focusing on the communities in two coastal towns on the west coast of Sri Lanka, Negombo and Chilaw, with an objective of evaluating and assessing the governance and the sustainable utilization and management of coastal resources there. The survey was carried out in December 2013, and consisted of face-to-face interviews and gathering information from households along the beach border that were selected through systematic sampling approach and from randomly selected stake holders on the beach, to satisfy the questionnaire. The chief executive officers of local government authorities viz. regional office of the Coast Conservation and Coastal Resources Management Department, Municipal Councils, Police Stations, and where necessary the incumbent of the Catholic Church in the area, were also interviewed to evaluate their role over the governance and management of the coastal resources. The analysis of survey data revealed that the major resource based income generation activities in Negombo beach was tourism (68%) while in Chilaw it was fisheries (75%). The major environmental issues in Negombo beach were pollution (35%), littering the beach by local tourists (27%) and illegal building constructions (20%), while those in Chilaw were pollution (43%), illegal house constructions (25%) and coastal erosion (26%). Therefore, the Negombo beach was cleaner (76%) than the Chilaw beach (27%). Since the major income generation activity in Negombo beach was tourism, the local government authorities paid special attention in maintaining law and order, carrying out beach cleaning programmes, daily removal of litter and waste, carrying out community awareness programmes on the importance of beach on tourism and usage of soft and hard engineering techniques to prevent coastal erosion. In addition, every tourist hotel was found to clean the beach façades under their purview, and beach vendors also supported these programmes. In fisheries dominated Chilaw, the inputs by the local government authorities were minimum except the Urban Council collecting household waste on weekly basis from the roadside bins. However, the village has a very strong community based management strategy led by the Catholic Church. The church plays a pivotal role in harmonizing the village, educating villagers on the proper disposal of garbage, preventing sand mining and use of harmful fishing practices, and coordinating the local government authorities to maintain proper sanitation as well as law, order and peace in the area. In contrast, the tourism dominated coastal zone in Negombo is managed by a strong co-management strategy that involves the contribution of the local government authorities and major stakeholders on the beach such as tourist hotels and the local community on the governess and sustainable management of the coastal zone.Item Comparative evaluation of three environmental flow calculation methods at Ketawala anicut of Aththanagalu Oya, Sri Lanka(Department of Zoology and Environmental Management, University of Kelaniya, Kelaniya, Sri Lanka., 2016) Udayanga, N.W.B.A.L.; Najim, M.M.M.Calculation of Environmental Flows (EFs), which are required for the sustenance of aquatic ecosystems in their original pristine state, often emerge as a prominent challenge to the sustainable management of water resources due to their complicity and difficulty of estimation. Being a tropical country that is heavily depended on its agriculture based economy, Sri Lanka often face the challenge of EF estimation during diverse irrigational and drinking water extractions. Lack of technology and expertise, and limitations in the long-term data have directly contributed for the wide utilization of rapid EF estimation methods. Therefore, the current study intends to evaluate the performance of such three widely practiced EF estimation methods, namely Tennant, IUCN and CEA methods for the EF estimation at Ketawala irrigational scheme. The Hydrologic Engineering Centre - Hydrologic Modelling System (HEC-HMS) version 3.5 model was calibrated and validated for the Aththanagalu Oya catchment and the daily river flow values for the past thirty five years (1981-2015) were generated at the pre-weir of the Ketawala anicut. The flow duration curve at the pre-weir of the Ketawala anicut was constructed (via the Gumbel approach) using the above simulated flow regime and the EFs that are applicable for the anicut were estimated via Tennant, IUCN and CEA methods in accordance with the standard methodologies. The Tennant method recommended an EF regime of 4.08 m3/s to be maintained at the post weir of the Ketawala anicut, while IUCN and CEA methods recommended EFs of 11.11 and 11.91 m3/s, respectively. Yet, EFs recommended by all these methods mostly remained higher than the average monthly flows in the dry season while considerably lower than the average monthly flows in the wet season at Ketawala, limiting the practical applicability of the estimated EFs. Furthermore, all these methods remained subjective and less responsive to the variations in the hydrological regime, while neglecting other major ecological components (biota and physic-chemical factors etc.) in an aquatic ecosystem. Hence, regardless of their wide applicably for EF estimation in Sri Lanka, the Tennant, IUCN and CEA methods failed to yield practically and environmentally acceptable EFs for the Ketawala anicut.Item Environmental flow requirements for Kinigama anicut in Uruwal Oya, Sri Lanka(Department of Zoology and Environmental Management, University of Kelaniya, 2015) Udayanga, N.W.B.A.L.; Najim, M.M.M.Item Recent trends in the rainfall patterns in the Mannar, Sri Lanka(Department of Zoology and Environmental Management, University of Kelaniya, 2015) Udayanga, N.W.B.A.L.; Najim, M.M.M.Item Evaluation of the spatial and temporal trends of dengue outbreaks in Kolonnawa urban council, Western province, Sri Lanka(Department of Zoology and Environmental Management, University of Kelaniya, 2015) Udayanga, N.W.B.A.L.; Kodithuwakku, K.A.R.K.; Najim, M.M.M.Item Evaluation of the Spatial and Temporal Trends in Household Solid Waste Disposal in Sri Lanka Using Geo-Informatics and Statistical Tools(Department of Zoology, University of Kelaniya, Kelaniya, Sri Lanka, 2014-06) Udayanga, N.W.B.A.L.; Kodituwakku, K.A.R.K.Generation of solid waste in large quantities and their improper disposal associated with the accelerated economic and technological advancement and population growth have raised growing concerns throughout the world including Sri Lanka. The complication of the composition and the quantitative increase of household waste have become a major issue in Sri Lanka. Localized trends in solid waste disposal play a critical role in drafting of policies and management plans for effective management of solid waste. Thus, a statistics and geoinformatics based analysis of the recent trends in household solid waste disposal was carried out to identify the characteristic disposal methods of household solid waste of each district, and to evaluate both spatial and temporal trends in household solid waste disposal patterns in Sri Lanka in order to facilitate the effective management of solid waste. Commonly practiced household solid waste disposal methods and percentage contribution of each method in each district in 2006-2007, 2009-2010 and 2012-2013 were obtained from the Department of Census and Statistics, Sri Lanka. The data were then subjected to Principal Component Analysis (PCA) to identify the major characteristic household solid waste disposal methods and the temporal variation of the household solid waste disposal methods in each district, by using PRIMER V 5.2.9. software package. Characteristic disposal method(s) of household solid waste in each district during the study period were recognized based on the scores of the Principal Components and districts that exhibit similarities in the disposal methods were grouped into clusters. Spatial maps of above recognized clusters that exhibit similar characteristic disposal methods were prepared using Arc GIS 9.2 and the spatial and temporal variation of such clusters were analyzed to identify the recent trends in household solid waste disposal. Generation of solid waste in large quantities and their improper disposal associated with the accelerated economic and technological advancement and population growth have raised growing concerns throughout the world including Sri Lanka. The complication of the composition and the quantitative increase of household waste have become a major issue in Sri Lanka. Localized trends in solid waste disposal play a critical role in drafting of policies and management plans for effective management of solid waste. Thus, a statistics and geoinformatics based analysis of the recent trends in household solid waste disposal was carried out to identify the characteristic disposal methods of household solid waste of each district, and to evaluate both spatial and temporal trends in household solid waste disposal patterns in Sri Lanka in order to facilitate the effective management of solid waste. Commonly practiced household solid waste disposal methods and percentage contribution of each method in each district in 2006-2007, 2009-2010 and 2012-2013 were obtained from the Department of Census and Statistics, Sri Lanka. The data were then subjected to Principal Component Analysis (PCA) to identify the major characteristic household solid waste disposal methods and the temporal variation of the household solid waste disposal methods in each district, by using PRIMER V 5.2.9. software package. Characteristic disposal method(s) of household solid waste in each district during the study period were recognized based on the scores of the Principal Components and districts that exhibit similarities in the disposal methods were grouped into clusters. Spatial maps of above recognized clusters that exhibit similar characteristic disposal methods were prepared using Arc GIS 9.2 and the spatial and temporal variation of such clusters were analyzed to identify the recent trends in household solid waste disposal.Item Evaluation of the trends in climate change with respect to severity and frequency of occurrence of wet and dry events of rainfall in Aththanagalu oya basin(Department of Zoology, University of Kelaniya, Kelaniya, Sri Lanka, 2014-06) Udayanga, N.W.B.A.L.; Najim, M.M.M.Socioeconomic aspects of life have changed due to alterations in the climatic patterns. Sri Lanka needs to pay more attention to the climate extremes as the available water resources are directly affected by these changes. Hence planning and management of water resources based on climatic patterns play a key role in sustainable development. Sustainable planning and management of water resources of Aththanagalu Oya that feeds many large and small scale multi-purpose water extraction schemes in Sri Lanka is vital in the event of climate change. Thus, an analysis of the shifts and trends of climatic patterns with respect to wet and dry events within the Aththanagalu Oya basin was carried out to evaluate the state and the extent of climate change using Standardized Precipitation Index(SPI). Daily rainfall data covering the period from January 1991 to February 2011 of Henarathgoda, Vincit, Chesterford, Kirindiwela, Nittambuwa and Pasyala rainfall gauging stations which are located within the Aththanagalu Oya catchment area were obtained from the Department of Meteorology, Sri Lanka. Two periodic intervals of years (1991-2000 and 2001-2011) were formulated and monthly accumulated rainfall for each month of the considered periods were used as the input to the SPI Model in Mat Lab R2007b (version 7.5). The events were ranked into five classes (normal, mild moderate, severe and extreme) based on the severity of each event and the variations in climate (with respect to SPI) were evaluated using Paired Chi-Square method. A decrease in dry events and an increase of the wet events in the climatic pattern of recent years (2001-2011) compared to the past (from 1991 to 2000) in Vincit, Kirindiwela, Nittambuwa and Pasyala could be observed in accordance with the SPI analysis while an opposite trend was observed in Henarathgoda and Chesterford. Unlike the predictions of many studies which expect significant alterations in climate patterns in the recent years than the past years, according to the SPI approach, only the wet events of Pasyala (a significant increasing trend of wetness) and the dry events of Vincit (a significant decreasing trend of dryness) indicate significant alterations in climatic patterns while the climatic variations indicated by the rest of the areas are statistically insignificant. Hence, a significant increase in wetness in Vincit and Pasyalain terms of both severity and frequency of occurrence with variations of rainfall seasonality could be predicted in accordance with the SPI.