Browsing by Author "Weerasinghe, V.P.A."

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Agricultural drought assessment using MODIS satellite data in Kurunegala District
(Department of Zoology and Environmental Management, University of Kelaniya, Kelaniya, Sri Lanka., 2016) Gamanayake, B.G.N.N.; Kadupitiya, H.K.; Weerasinghe, V.P.A.
Drought is a climatic anomaly characterized by long spell scarcity of water. Agricultural drought is usually defined by less availability of soil water to maintain crop and forage growth by the deficiency of normal precipitation over an identified period of time. Since drought is a creeping phenomenon which appears slowly and resulting web of impacts not only to agriculture but also for all other aspects, monitoring, forecasting, evaluating impact and proposing solutions to drought hit areas are challenging than other disasters. Distinct to point observations of ground data, remote sensing provides direct spatial information on vegetation stress that occur due to drought conditions. This facilitates the utilization of time series Vegetation Indices derived using time series satellite data for continuous monitoring of vegetation conditions and tracking drought occurrences. MOD13Q1 (250m, 16-day) satellite images, which contain NDVI (Normalized Difference Vegetation Index), were used in this study and Vegetation Condition Index (VCI) was calculated using ENVI 4.5 Remote Sensing software for agricultural drought monitoring in Kurunegala District during the year 2000-2015. Spatial variability of drought frequencies was evaluated and mapped using ILWIS 3.4 free software. Map accuracy was assessed using actual drought data available for Kurunegala district in the database of Disaster Management Center. According to the results, North and North-West parts of Kurunegala District were identified as severe agricultural drought prone areas. In order to enhance the accuracy, water mask was recommended.
Catchment based water quality evaluation of Pugoda Ela in Gampaha district, Sri Lanka
(Sri Lanka Association for Fisheries and Aquatic Resources, 2012) Samadaree, A.D.S.; Weerasinghe, V.P.A.
Pugoda Ela is one of the main tributaries of Kelani River which is used for water supply to Colombo and Gampaha districts by National Water Supply and Drainage Board (NWSDB) in Sri Lanka. Limited recent studies are available on water quality of the catchment of this import tributary. Therefore Pugoda catchment was selected as the study area and was divided into four sub catchments defined as Sub catchment A, B, C, and D. Main objectives of the study were to identify the point and non- point sources of pollution and evaluate each source by comparing water quality parameters such as temperature, pH, TDS, conductivity, BOD5, COD, DO, NO',-N and total Coliform. Sample collection was carried out twice a month from February to July 2011 to study the water quality including wet and dry period of the 'Vala' season. The only identified point source was South Asia Textile Industry. Agricultural lands and animal husbandry were the major non-point sources of pollution in the area. The study was also planned to investigate the contribution of inorganic fertilizer application of paddy cultivation on the water quality of Pugoda Ela, on sub catchment basis. BODs values in all sub catchments were significantly different from each other in wet and dry seasons (P < 0.05) and ranged from 6.9 :t 0.147 to 10.578 :to.513 mg/I in dry season and from 4.778:t0.368 to 8.233:t0.261 mg/I in wet season .COD values in sub catchment A, Band D were not significantly different from each other in dry season (P > 0.05) and catchments ranged from 8.032 :t 0.679 to 9.617 :to.346 mg/I in dry season and 8.517:t0.679 - 1O.000:t0.318 mg/I in wet season. COD in sub catchment D was significantly the highest (P < 0.05) in both seasons of all sub catchments.NO-3-N concentration values in outlets of sub catchments ranged from 2.863:t0.721 to 7.969:t0.755 mg/I in dry season and ranged from 4.09:tl.160 to 7.5l4:t0.559 mg/I in wet season over the study period. NO-3-N concentration values in catchment A, Band C were not significantly different from each other in dry season (P > 0.05) and ranged from 2.863:t0.72l to 7.969:t0.755 mg/I in dry season and ranged from 4.09:tl.160 to 7.5l4:t0.559 mg/I in wet season. NO-3-N concentration values in sub catchment D was significantly highest (P < 0.05) in both seasons of all sub catchments. Total Coliform (MPN/ lOOm!) values in outlets of sub catchments ranged from 220.8:t1O.000 to 245.0:t17.l00 (MPN/ lOOm I) in dry season and ranged from l29.2:t13.600 to 258.3:t45.300 (MPN/ 100ml) in wet season over the study period. Total Coliform (MPN/ 100ml) values in all sub catchments were not significantly different from each other in dry season over the study period (P > 0.05). The highest amount of urea application 2050 tons per month was observed in sub catchment 0 where the highest extent of paddy cultivation occurs. The highest average load of total Coliform 450000 (MPN) was found in sub catchment B which had the highest population density. Although average level of COO of point source was high, the other measured water quality parameters were at permissible level of Sri Lankan inland surface water standards established by CEA. It is concluded that according to the CEA standards, Pugoda Ela consisted bathing quality water or with complete treatment it can be used as a source of drinking water.
A census of diurnal primates in the villages located between Labugama-Kalatuwawa and Indikada forest reserves in Colombo District of Sri Lanka.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Panagoda, P.A.B.G.; Weerasinghe, V.P.A.
The diurnal primate populations which inhabit the villages, located between Labugama-Kalatuwawa and Indikada Forest Reserves in Colombo District of Sri Lanka, has a high conservation value due to the presence of critically endangered Semnophithecus vetulus nestor (Western purple-faced langur). In addition, these diurnal primate populations consisting of S. vetulus nestor and Macaca sinica (Toque macaque have caused many human-monkey conflict incidents within the area. No studies have assessed the local populations of diurnal primates within this area in spite of its importance in both above perspectives: conservation and conflict. Therefore, this study was aimed to assess the relative density and group size of diurnal primates and to statistically compare above two estimations between the two primate species. The census was carried out within a selected stripe of villages located between the two forests. Using reconnaissance walks, five trails (2 km each) were established to represent the study area, with a systematic sampling design. The trails were walked simultaneously, by five independent trained teams each consisting of five persons, in the morning and afternoon on 3rd of December, 2016. In addition, group counts of monkeys were made during 10 opportunistic field visits, from April to December 2016. For each species, the average group size and group and individual encounter rates (as a measure of relative density) were calculated. The group sizes and encounter rates of the two species were then statistically compared using Mann-Whitney U test. Group size of S. vetulus nestor (mean ± SE) was lower (4.46 ± 0.40 individuals) than that of M. sinica (8.29 ± 2.19 individuals), even though the median group sizes of the two species were not significantly different (p=0.1893). On the other hand, S. vetulus nestor was found to be more abundant in the area compared to M. sinica. The number of encounters of S. vetulus nestor and M. sinica during the census was 10 and 4 respectively. Further, the average group encounter rates (mean ± SE) of S. vetulus nestor and M. sinica, were 0.95 ± 0.31 and 0.33 ± 0.23 respectively (no. of groups/km) whereas the average individual encounter rates (mean ± SE) of S. vetulus nestor and M. sinica, were 4.23 ± 1.38 and 2.71 ± 1.89 (no. of individuals/km) respectively. However, no significant difference was found between the median group (p=0.470) and individual (p=0.4647) encounter rates of the two species. Yet, the higher abundance of S. vetulus nestor over M. sinica, could also be observed during the opportunistic observations made throughout the whole study period (opportunistic group encounters; 22 for S. vetulus nestor and 9 for M. sinica). The reliability of the results can further be improved by censusing at different times of the year. As this study sets a baseline, future studies are recommended to identify any growth or decline of this crucial population of primates.
Determination of an eligible location for installation of a solar panel system in the University of Kelaniya using GIS
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Heshani, A.L.S.; Athukorala, S.M.W.; Leelarathna, W.D.S.R.; Weerasinghe, V.P.A.
According to the international energy agency, the role of renewables continue to increase in the electricity, heating and cooling and transport sectors. Newly develop technology in photovoltaic cells that have the potential to dramatically increase solar power generation in the next two decades. Being closer to the equator, Sri Lanka has a great opportunity to have solar energy throughout the year almost 5-6 hours per day. Sri Lankan power supply organizations are mainly depending on diesel, coal and hydro power. Still we do not have enough sources to supply electrical energy throughout the country. All the energy sources except hydro power are not considered as environmental friendly since they emit high amount of carbon to generate power. Being the first Green University in Sri Lanka, University of Kelaniya has initiated many approaches for energy conservation within the University. This study was carried out to find out the most suitable location within the University for installation of a solar panel system using ArcGIS software. For this, surface area of roof of buildings, height of buildings, elevation of the land, disturbance from other structures such as buildings and trees were selected. Map layers were created by using high resolution satellite image. Surface elevation profile was created by using available contour lines. Building layer was digitized from the satellite image using ArcGIS software. After overlaying all layers together suitable roofs were selected for the solar panels to install. In order to find possible energy in the area, meteorological data was collected including minimum and maximum atmospheric temperature, rainfall, and sunshine hours from Welisara meteorological station which is the nearest meteorological station to the University. The mean values of meteorological parameters obtained for the past 8 months were as follows; maximum atmospheric temperature of 28.28 0C and minimum of 26.02 0C, rainfall of 171.92 mm and sunshine hours were 7.6 hours. After selecting suitable buildings from the map, visual observation was done to calculate roof area of each building manually. The building with the highest surface area and minimum disturbance from adjacent structures was selected as the best suited location. The best suited location was selected and also it shows the highest monthly average consumption of electricity among other university buildings. Apart from that suitable lands also can be considered. But as the availability of lands in the university premises is a limited factor, priority was given to the rooves of the buildings. It is easy to make 3D view of the University by using 3D Analyst, if there is a higher resolution Digital Elevation Model (DEM). Roof structure and the shape can be used to maximize the efficiency of solar panels. GIS can be used as a supportive tool in optimization of determining the best suited location for the solar panel installation.
Development of a disaster risk map using GIS for Panadura urban council area: a pre-requisite to the urban planning
(Department of Zoology and Environmental Management, University of Kelaniya, 2015) Jayasinghe, L.; Karunarathne, M.K.H.S.; Lakmali, A.A.R.; Ranjitha, L.K.H.K.; Weerasinghe, V.P.A.
Development of flood inundation map for Deduru oya basin and flood risk analysis: public participatory approach
(Department of Zoology and Environmental Management, University of Kelaniya, 2015) Lankadhikara, L.M.P.P.; Kalhari, I.N.; Kularathna, G.N.S.P.M.; Haafi, M.M.B.; Weerasinghe, V.P.A.
Identification of suitable landfill sites for solid waste disposal in the Matara District using Geographical Information Systems and the Analytic Hierarchy Process
(Sri Lanka Association for the Advancement of Science, 2011) Jayawickrama, N.T.; Weerasinghe, V.P.A.
Improperly placed solid waste dumping sites have created numerous environmental and social problems in the society. Such impacts could be minimized by implementing proper landfills in suitable locations. Even though Matara is a highly populated district, it lacks properly planned landfills. The objective of this study was to select suitable sites for solid waste landfills in the Matara District using the Geographic Information System and the Analytical Hierarchy Process. Existing national and international landfill site selection regulations and guidelines were reviewed to prepare eleven landfill site criteria namely; surface water body, forest reserve, wetland, coastal zone, rainfall, town centre, residential area, important building, major road and railway, slope and soil. These criteria were divided into two parts, constraint criteria and factor criteria. Constraint criteria divide the district into suitable and unsuitable areas for landfill site placement. Factor criteria classify the suitable areas for landfill placement into high, medium and low suitable areas. Each constraint criterion was mapped using GIS. All eleven constraint criteria maps were overlaid to prepare the final constraint map. From the total area of Matara district, 1100.16 km2 (85.7%) is unsuitable for landfill placement. The remaining 182.34 km2 (14.2 %) land area of the district was further evaluated using factor criteria and was classified into three groups of high, medium and low suitability. When determining the relative importance of each factor criterion Analytic Hierarchy Process was utilized. The resulting final factor map revealed that 112.4 km2 (8.8%) of land in the Matara District is highly suitable for placing landfills. Field investigations within the Matara Divisional Secretary Division were carried out to validate the data obtained from the final factor map. It was found out that one site at Thalpawila, one site at Parawahera and two sites at Kekanadura were suitable for landfills in Matara Divisional Secretary Division. The final decision for landfill site selection will require more detailed field studies.
Investigation of water consumption pattern in University of Kelaniya
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Lekamge, M.L.D.; Dayananda, M.D.N.R.; Shanthamareen, M.; Weerasinghe, V.P.A.
Water Consumption is an environmentally and socially concerned aspect. Close observation of the water consumption pattern, help to apply water conservation measures effectively. The main objective of this study is to investigate the water consumption pattern in University of Kelaniya during last thirty-one (31) months from January 2014 to September 2016. During this period, university has received four water bills each month. Water bills and student intake details were collected from the administration division. Data was analyzed using Microsoft Excel. This study also investigated students’ attitudinal changes in water consumption after the implementation of the polythene prevention policy. A questionnaire survey was conducted among randomly selected 200 students in the Faculty of Science, in order to assess the water consumption pattern in Science Faculty canteen before and after the implementation of polythene prevention policy. The data obtained from administration division shows and increase in annual water consumption. The average monthly water consumption is 18,551.32m3 and average monthly cost for water consumption is 821,870.90 LKR. The average daily water consumption per head in the University is 0.06342 m3 (63.42L). According to the WHO (World Health Organization) standards about 20 L water per capita per day should be assured to maintain basic personal and food hygiene. The highest water consumption has observed in the canteens and hostels whereas the lecture halls have the lowest water consumption. According to the results the monthly water consumption and monthly total charge shows an increasing trend with fluctuations. From January to February there is a sharp increase of the monthly water consumption as a result of the student intake. A peak water consumption is observed during the March – April in each year. As a tropical country Sri Lanka receives high amount of solar radiation during that period. Therefore, the water consumption increases due to the temperature increase. The depressions in the curve is observed in the vacation and study leave periods. University of Kelaniya has implemented a polythene prevention policy beginning from the 1st of September, 2016. As a result of that the use of polythene and lunch sheets have been banned within the university canteens. The highest percentage of students shifted from university dinner packets to outside is observed during the dinner time is 20.5%. The highest percentage of students shifted from lunch packets to plates is observed during the lunch time is 43%. This might be affected to the water consumption due to washing plates. This is a preliminary study to investigate the water consumption pattern in the University of Kelaniya. There should be a well maintained database for identifying water consumption and to have separate water meters for each Faculty to apply water conservation methods according to the cleaner production policy. It will help to reduce the water consumption in each Faculty. Using those information water conservation strategies such as introduction of push taps, sensory taps and rain water harvesting system can be implemented in order to save more water.
Lesson 01: Measurement of meteorological parameters/variables which are affecting biosystems
(Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Weerasinghe, V.P.A.
Locating Suitable Sites for Solid Waste Landfills in Matara District Using GIS and AHP
(Department of Zoology, University of Kelaniya, Kelaniya, Sri Lanka, 2014-06) Jayawickrama, N.T.; Weerasinghe, V.P.A.
Landfill site selection in highly populated areas is a critical issue in today‘s society because of its enormous impact on the economy, ecology and the environmental health of the region. Present study was conducted to find suitable locations for landfills in Matara district, which is a highly urbanized area. Geographic Information Systems and Analytic Hierarchy Process were integrated in this study to solve the landfill site selection problem. Waste collection and population data of the study area were used to estimate the cumulative waste amounts up to the year 2020 and the minimum effective area needed for landfill sites. Eleven landfill siting constraint criterion maps including surface water, forest reserves, wetlands, coastal zone, rainfall, town centres, residential areas, important buildings, major roads and railways, slope and soil were prepared and unsuitable areas for landfills were determined according to the existing regulations. Further evaluation of the remaining suitable areas in three categories of high, medium and low priority for being suitable for landfill sites was done using factor criteria. Depending on the relative importance of the identified criteria, weights were calculated by Analytic Hierarchy Process and were incorporated in to the analysis. The maps prepared for each criterion were then overlaid in Geographic Information Systems environment to obtain the final suitability. The resulting final factor map shows a land area of 112.4 km2 from Matara district as highly suitable for landfill areas. Field investigations show that Thalpawila, Parawahera and Kekanadura have most suitable areas for landfill sites at Matara district.
Mapping and suitability study of existing locations of waste collection bins at University of Kelaniya
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Handapangoda, H.M.A.K.; Jayawardana, H.A.D.A.K.; Weerasinghe, V.P.A.
Solid waste management is one of the major environmental and social problems in Sri Lanka. Waste without proper segregation is the one of the main roots of barrier to implement solid waste management systems. University of Kelaniya has established waste collecting bins in different locations in the university premises in order to facilitate waste management within the university premises. The main objective of this study is to map the existing locations of the waste collecting bins in the University using Geographical Information System (GIS). Other objective was to find out the suitability of the existing locations of the waste collecting bins. There are two types of waste collecting bins at University premises. Namely, waste separated bins; biodegradable waste (green), paper waste (blue), polythene and plastic waste (orange), glass (red) and non-separated bins. Locations of the both types of bins were recorded using GPS Garmin eTrex 10 model. GPS data was transferred to ArcGIS10.2 software to map the locations of waste collecting bins. Base map was created by using high resolution satellite image. Building layer, road layer including foot path were digitized using ArcGIS 10.2 software and vector map was developed. Digitized vector layers and transferred GPS points layer were overlayed using overlay function in ArcGIS 10.2 software. Map layout was prepared to show the locations of waste collecting bins. Suitability of the existing locations of the waste collecting bins were studied according to the waste generation amounts in different places. Students canteens, staff canteens, student hostels, student recreational areas were identified as the main waste generation places at Dalugama premises in University of Kelaniya. Amount of waste generated was measured by using a spring weighing scale. Frequency of data collection was once a week. Microsoft Excel was used to analyze the data. The minimum and maximum range of bio degradable waste generation in Dalugama premises was 580-610 kg and non-bio degradable amount was 250-300 kg. Results show that the majority of separated bins are located in high waste generation places. Also it was clear that the generation amount of each type of waste depend on the type of the building, size of the building, amount of staff and students visited or worked and accessibility to bins. Further improvements are recommended in waste collection methods such as not to use separated bins to collect non separated waste and not to use non separated bins to collect separated waste. This will mislead the user when disposing garbage. Existing location of waste bins map can be used as a guide to the administration work as well as visitors and workers in the university.
Mapping of Water Pollution in Pattiwila Area of Gampaha District, Sri Lanka, Using Surface Interpolation Method
(Department of Zoology, University of Kelaniya, Kelaniya, Sri Lanka, 2014-06) Perera, L. N.W.; Weerasinghe, V.P.A.
Industries can be a huge source of water pollution and extremely harmful effects could be produced when there are no proper effluent discharge mechanisms. Residents in the Mabima West, Pattivila North and Pattivila South Grama Niladhari (GN) divisions of the Biyagama Divisional Secretary‘s Division in Sri Lanka also have health problems due to the water pollution in this area. Some years ago, the Pattiwila canal, which is a stream running through these GN Divisions was directly connected to the livelihood of the people living in Mabima and the Pattiwila region but today the water quality of this canal has been negatively affected by the wastewater discharges from several industrial activities of the study area. Sapugaskanda oil refinery, Sapugaskanda diesel power plant and gas filling industries are most possible effluent discharge sources to the Pattiwila canal. The present study was carried out to investigate the spatial variation of water quality in the study area using surface interpolation method and compare with relevant water quality standards. Fourteen water quality parameters of surface and ground water in seven sampling sites were analyzed according to the standard procedures. Data was interpolated using ArcGIS 9.1 software and Inverse distance weighting (IDW) method was used as the surface interpolation method. Results indicated that, oil and grease levels in water exceed the water quality standard for use as raw water for public water supplies and drinking purposes. It is not safe to use water as raw water for public water supplies, drinking purposes and irrigation and agriculture purposes without proper treatment, especially for oil and grease.
A potential habitat corridor for Western Purple-faced Langur between Forest Reserves in Sri Lanka: GIS as a tool in connectivity modelling
(Acta Ecologica Sinica, 2019) Panagoda, P.A.B.G.; Weerasinghe, V.P.A.
Endemic Western purple-faced langur (Semnophithecus vetulus nestor) of Sri Lanka, is an exclusively arboreal, critically endangered primate whose habitats are severely fragmented with the human population expansion. Labugama-Kalatuwawa Forest Reserve (LKFR) which is identified as the last strongholds for maintaining viable populations of the species over the long-run and Indikada Mukalana Forest Reserve (IMFR) which is located in a closer proximity to LKFR have no connection with each other at the current status. As there is no assertion of regional habitat connectivity at a metapopulation context, the study aimed to identify a potential habitat corridor for S. v. nestor between LKFR and IMFR by using GIS as a tool in connectivity modelling. Study area was first divided into 0.04 km2 grids using ‘fishnet’ tool. Fivemain resistance criteria for S. v. nestor movementwere selected namely; land use, road density, canopy cover, human tolerance and Feeding Plant Species Richness and Density (FPSRD). Each grid was assigned with resistance values for above criteria ranging from 1 to 6. Overall resistance layer for S. v. nestor movement was created using ‘weighted overlay’ in GIS environment. The best potential habitat corridorwas identified via least-costmodelling. The resultant corridor fallswithin an areawhichmainly comprises of forest and rubber (Hevea brasiliensis) monoculture. It further accounts for the highest human tolerance, canopy continuity, FPSRD and least road density. Resultant corridor can be improved by bridging existing gaps and enriching the corridor habitatswhichwould play an important role in conservation of S. v. nestor by minimizing the isolation of local populations, ensuring the gene flow and maintaining the minimum viable metapopulation in the long run. This study further demonstrates that GIS can be used as an effective tool for least-cost modelling which helps to identify potential wildlife movement corridors at minimum cost.
Rainfall-Runoff-Inundation (RRI) model for flood analysis in Attanagalu Oya basin, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Kelaniya, Sri Lanka., 2016) Dikkumbura, H.K.U.S.; Weerasinghe, V.P.A.
Floods are one of the most critical forms of natural hazard in global and local context. In the case of large scale flooding, it is important to identify the flood inundation areas and map the areas that undergo flooding for future flood management plans. This study analyzed rainfall-runoff and inundation in the Attanagalu Oya basin with the Rainfall-Runoff-Inundation (RRI) model that simulates the rainfall-runoff and inundation processes simultaneously based on two-dimensional diffusion wave equations. The applicability of RRI model to simulate flood inundation areas over the Attanagalu Oya basin was also investigated. RRI model simulation was conducted with satellite-based topographical data and daily satellite-based rainfalls for the period of 15th to 18th May of 2010 which was the most recent destructive flood occurred in Sri Lanka.Water depths on slope, water depths on river and river discharges at a specific time step were obtained as output. The model performance was evaluated using satellite-based vector flood map in 2010 obtained from the Disaster Management Centre and river discharge data at Dunamale obtained from the Department of Irrigation, Sri Lanka. The simulation results showed 74.31 % accuracy in downstream flood inundation extent with vector flood map. The simulation under-predicted the flood inundation in upstream areas and tributaries due to the coarse resolution of digital elevation model. The relative error of river discharge data shows some underestimation of simulated flow discharges as it is -20.17 %. The model simulation was found to be capable of obtaining the peak flood inundation extent in downstream of basin due to its flat topography. RRI model can be used for the ungauged basins with no flow data available as its simplicity, requiring only rainfall input.
Selecting suitable locations to establish a ground solar farm in Trincomalee District in Sri Lanka using GIS
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Senadeera, T. S. M.; Bandara, W. M. J. Y.; Herath, H. M. A.; Ariyawansha, J. M. M. S.; Weerasinghe, V.P.A.
Renewable energy is energy derived from natural sources that are regenerated at a higher rate than consumed. One of the examples of the most effective renewable energy sources is solar energy, which is derived from the sun. Solar energy can be extracted directly or indirectly for human use. With the rapid growth in energy demand, solar energy has led to an increased interest in power generation. In Sri Lanka, solar energy investments have developed rapidly in recent years. The ground solar farm is one of the solar energy harvesting types for electricity generation, especially at the industrial level. Our main focus is to provide an additional power supply to the National Grid of Sri Lanka, and this study focuses on utilising Geographic Information Systems (GIS) to identify suitable areas for establishing a ground solar farm in the Trincomalee District, Sri Lanka. Trincomalee District has a tropical wet and dry climate with high sunlight. According to that Trincomalee District was selected as the study area by considering solar irradiation and by focusing on the cumulative solar power plant capacity in Sri Lanka. According to the literature review, various factors can be useful for selecting locations for a ground solar farm. Land surface temperature, slope, land use, and proximity to roads were selected as criteria for this case study. The separate criterion maps were generated and they were reclassified according to the requirements, and those were used with Analytical Hierarchical Process (AHP) to find the weights for overlay analysis in GIS. The resulting final factor map shows a land area of 24.47 km2 for Trincomalee District as highly suitable for establishing a ground solar farm. This case study aims to reduce the overconsumption of natural resources that are used to produce energy and to ensure the protection of the environment through using renewable energy.
Selection of suitable site for establishing a biogas unit using GIS: Case study in University of Kelaniya
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Wadasinghe, L.G.Y.J.G.; Gnanasingha, S.M.; Weerasinghe, V.P.A.
Bio degradable waste management is one of emerging environmental issues in Sri Lanka due to higher moisture levels. As a first green university of Sri Lanka, the University of Kelaniya implements their green policy towards sustainable environment. Bio degradable waste can be managed either by composting or bio gas generation since they are the currently available most cost-effective management methods. Composting alone it needs bigger land to manage all biodegradable waste within the university. Bio gas unit will helps to reduce the land usage for waste management in the University. Bio gas can be used as an alternative fuel source to reduce the consumption of LP gas within the university. Generated sludge can used as fertilizer to preserve the gardening. The main objective of this case study is to identify a suitable site to implement a bio gas unit in the University of Kelaniya by using ArcGIS 10.2 software. Three major criteria were selected namely generated waste amount, bare land, and road accessibility. If it is closer to higher waste generation places, it will save the energy in transportation. Road accessibility is needed to bring waste to the bio gas unit. By using higher resolution satellite image of university of Kelaniya, boundary of the university, building layer and road layer were digitized using ArcGIS software. Since there were no records of biodegradable waste generation in different buildings in the university premises, primary data collection was done. Student hostels and canteens were used to identify the amount of bio degradable waste since they are the identified highest bio degradable waste generation places. Waste was measured by using a spring weighing scale. For analysis, collected data was added to the new layer called waste generated places. Layers were converted into raster format and then reclassify all the layers. Majority amount of waste was generated in gymnasium student canteen and girls’ hostels which ranges from 300-340 kg per day. Buildings with higher waste generation was selected in separate layer. Bare lands were selected using higher resolution image classification and manually update it. Then selected building layer, road layer, and bare land layer were overlaid using weighted overlay method to find out the suitable sites for the bio gas unit. Map layout was developed to show the suitable sites for the bio gas unit in University of Kelaniya. The most suitable place was selected after visual observation. The proposed area for the bio gas unit should not be too closer to hostels, or lecture halls for safety purposes. This map could be used by any responsible party such as administration division or Green committee for their future waste management planning purposes. GIS is an important tool to identify suitable area maps to save time in decision making.
The spatial variability of physicochemical parameters of mangrove soil and mangrove species in Negombo Lagoon, Sri Lanka
(Elsevier, 2024) Wickramasingha, W.S.B.; Weerasinghe, V.P.A.
Mangrove forests are unique and invaluable ecosystems due to their role in biodiversity, coastal protection, and carbon sequestration. This study examined spatial variability of selected physicochemical parameters of mangrove soil and species distribution at the Negombo lagoon. Eighteen sampling sites were selected based on judgmental sampling techniques. A 10 m x 10 m area was selected within the 1 km x 1 km grid to get the replicate soil samples from 0 − 15, 15–30 and 30–45 cm depths from the surface. Further, a vegetation survey was conducted to identify mangrove species in the same 10 m x 10 m area. Soil temperature, pH, salinity, and soil organic matter (OM) were analyzed using standard laboratory methods. Results show that temperature varied spatially from 25.2 °C to 30.0 °C, with the highest temperature recorded in the topsoil layer. Soil pH and salinity spatially varied from 5.39 to 8.31 and 0.56 % to 8.83 %, respectively. Soil organic matter spatially varied from 2.56 % to 15.7 % and increased with the increasing depth. Soils with high salinity tend to reduce OM by accelerating the mineralization of OM. Correlation analysis showed a positive relationship between salinity and OM (r = 0.57; P < 0.05). Rhizophora apiculata, Rhizophora mucronate and Avicennia marina were associated more in soils with high salinity (3.72 % − 7.15 %) and neutral to weakly alkaline pH. Bruguiera gymnorrhiza was more prevalent in soils with higher salinity (7.69 % − 8.83 %) and lower pH, while Lumnitzera racemosa was found in acidic to slightly alkaline pH but with low salinity (1.35 % − 1.92 %) soils. Sonneratia caseolaris was recorded in soils with the lowest salinity (0.83 % − 1.04 %). The findings offer valuable insights for decision-making processes for conserving and restoring mangrove forests, providing effective and sustainable environmental management strategies.
Statistical Tool to Address the Influence of Urbanization in Groundwater Quality in Colombo District, Sri Lanka
(SAGE, 2022) Antalyn, Babu; Weerasinghe, V.P.A.
Management of groundwater quality is becoming a key feature of a sustainable future while implementing sustainable development goals which are given by United Nations. During past decades, rapid land-use changes, urbanization, and population expansion are highly influenced the groundwater quality. To provide policymakers and water managers with reliable information on groundwater quality is a challenge to achieving sustainable development goals in developing countries. Therefore, this study intended to assess the spatial variability of groundwater quality using selected physicochemical parameters at the 39 available groundwater wells during the southwest monsoon period. Spatial variability is explained in 13 Divisional Secretariat Division (DSD) levels in Colombo district due to easier interpretation and management purposes. Afterward, groundwater quality was related to urbanization using population density and built-up density in 13 DSD levels in Colombo district, Sri Lanka. PCA (Principal Component Analysis) shows that 08 DSD levels are urban and 05 DSD levels are rural. pH (3.22–6.73), COD (8.91–52.9 mg/L), BOD5 (1.2–9.9 mg/L), and DO (2.17–5.05 mg/L) showed deviations from the given standards by local authorities in Sri Lanka. A significant relationship (p < .05) was found between urbanization and physicochemical parameters in regression analysis. The water quality index shows poor water quality indices in urban areas and vice versa in rural areas which is similar to the results obtained by statistical analysis. A sustainable urban development plan with continuous groundwater quality monitoring is necessary to protect groundwater resources in Sri Lanka.
Surface water quality assessment for the management of hydrological regimes: Kalu Oya and Mudun Ela catchment in Sri Lanka
(Environmental Nanotechnology, Monitoring & Management, 2021) Thotagamuwa, H.T.B.N.; Weerasinghe, V.P.A.
This study aims to assess the relationship between surface water quality and the land-use of an urban catchment named ‘Kalu Oya and Mudun Ela catchment’ located in the western province, Sri Lanka. Ten judgmental sampling locations of the streamflow were selected to measure water temperature, pH, salinity, conductivity, Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD₅), Chemical Oxygen Demand (COD), oil & grease, nitrate and dissolved phosphorous levels, flow rates over five months of the period from June to October 2018. All these parameters varied independently with a significant difference from other sites (ANOVA, p < 0.05). Water temperature and nitrate levels showed a strong clustering pattern with positive Moran’s index values supported by higher Z-scores. (Moran’s index 0.557 and 0.5106, Z-score 2.773 and 2.419 respectively). Higher oil & grease levels exceeding the accepted levels were observed at all the sampling sites. Oil & grease values showed a strong positive correlation with the flow rate (Coefficient-0.807, P value-0.005) revealing that higher oil & grease levels in the stream may be resulted by subsurface flushing. Site 02 is affected by the effluent discharged by the Colombo fish market having higher phosphate and TDS levels. Clustering pattern of nitrate and dispersed pattern of oil & grease of the Kalu Oya and Mudun Ela catchment show evidence of the poor drainage system in the catchment. Improving the drainage system may enhance water infiltration by reducing the volume of runoff and improve the water quality by that it can be used as an effective urban storm water drainage system in the hydrologic water regime.
A systematic literature review on integrating disaster risk reduction (DRR) in sustainable tourism (SusT): Conceptual framework for enhancing resilience and minimizing environmental impacts
(Elsevier, 2024) Jayasinghe, G.Y.; Perera, T.A.N.T.; Perera, H.A.T.N.; Karunarathne, H.D.; Manawadu, L.; Weerasinghe, V.P.A.; Sewwandi, B.G.N.; Haroon, M.H.; Malalgoda, Chamindi; Amaratunga, Dilanthi; Haigh, Richard
This literature review meticulously explores the integration of Disaster Risk Reduction (DRR) techniques into sustainable tourism (SusT), placing a focal point on enhancing resilience and mitigating environmental impacts. By examining several disciplines, including tourism management, disaster management, environmental science, green innovation, and sustainable development, this study recognizes major themes, research gaps, and best practices in this emerging subject. It underlines the importance of SusT and the need for effective DRR programs to alleviate the negative effects of catastrophes on tourism destinations and ensure their long-term sustainability and resilience. Science Direct, Springer, SAGE Publications, and Wiley's online library were the selected databases and the inclusion criteria were based on studies that looked at how DRR measures were implemented in SusT practices and how effective they were in increasing resilience and lowering environmental effects. The selected literature reveals many concepts and ways for integrating DRR in tourism, such as pre-disaster planning, risk assessment, capacity building, and stakeholder involvement. The assessment identifies the vital part played by government agencies, local entities, and tourist service providers in organizing and coordinating these programs. It points out potential obstacles to DRR integration within the tourism sector. The review emphasizes the importance of monitoring and measuring the outcomes of DRR programs in tourism, and it suggests the use of metrics and indicators to assess how well resilience-building and environmental impact reduction strategies are implemented. These insights may be utilized by policymakers, academics, and practitioners to design methods that enhnace the resilience of tourism destinations while minimizing environmental consequences.conditions in Sri Lankan marine waters, thus qualifying mangrove ecosystems in microtidal coasts as effective carbon sinks.