Browsing by Author "Edirisooriya, KVUI"

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item: Conference-Full-text
Analysis of beachrock samples along Southern and Western coasts of Sri Lanka by spectroscopic methods
(Department of Earth Resources Engineering, 2019-08) Edirisooriya, KVUI; Thilakarathna, MADP; Vijitha, T; Dassanayake, ABN; Jayawardena, CL; Dissanayake, DMDOK; Samaradivakara, GVI
Beachrocks are sedimentary structures commonly observed where there is warm sea water in tropical and subtropical regions as a result of cementation by CaCCb of coastal sediments in the tidal zone. Comprehensive studies have been carried out to determine the formation mechanisms of beachrocks specially Japan to improve an alternative countermeasure against erosion by man-made rocks. When focusing on formation mechanism of beachrocks elemental and mineralogical composition is vital. Considering this important application, we used spectroscopic techniques to understand composition of beachrocks in southern coastal region between Ahangama to Kaikawala and Uswetakeiyawa in the western coastal region of Sri Lanka. The presence of minerals in beach rock samples in southern coast were identified by FT-IR spectroscopic technique. The constituents of minerals present in the beach rocks are further confirmed by XRD technique. Elemental concentrations of beach rock samples have been analyzed using technique of WDXRF spectrometry. Uswetakeiyawa beachrock was mainly analyzed by using EDX in SEM. Beachrocks in southern coasts is comprise higher percentage of Aragonite which is the polymorph of CaCCb, frequently founded in most of the sites in the world. Further the composition shown similarities with Indian (Tiruchendru) and Japan (Okinawa) beachrock occurrences. Comparative to the composition of southern coast beachrock, XRD analysis did not indicate any CaC03 polymorphs Uswetakeyyawa, beachrocks. Instead it indicated the presence of Kutnohorite (Ca(Mn,Mg,Fe)(C03)2).
item: Conference-Full-text
Effects of covid-19 lockdown on lst, ndvi, lulc, and uhi: Dehiwala-Mount Lavinia case study
(IEEE, 2023-12-09) Madhurshan, R; Mushmika, PAS; Edirisooriya, KVUI; Ishankha, WCA; Dauglas, DLPM; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
The COVID-19 pandemic has had a profound global impact since its outbreak in late 2019. To curb the spread of the virus, measures were implemented to control its transmission, such as reducing human activities, shutting down industries, minimizing transportation, and practicing social distancing. A case study focused on the Dehiwala-Mount Lavinia suburb analyzed various environmental indicators during normal working days in April 2019 and the lockdown phase in April 2020. Landsat 8 (TIRS/OLI) images, processed with ArcMap 10.8.2 software, were used to examine the impact of the lockdown on environmental conditions by comparing Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI), Land Use/Land Cover (LULC), and Urban Heat Island (UHI). The results revealed a decrease in LST and an increase in NDVI during the lockdown. The analysis of LULC showed increased vegetation growth near the Aththidiya wetland area. A relatively cooler UHI was observed in 2020 compared to the year 2019. These findings underscore the influence of human activities on UHI and highlight the importance of urban planning and mitigation strategies to address UHI effects on local climates.
item: Conference-Abstract
Elemental and mineralogical analysis of beachrocks in Southern coastal region Sri Lanka
Dassanayake, ABN; Jayawardena, CL; Edirisooriya, KVUI; Thilakarathna, MADP; Thirunavukkarasu, V
Beachrock is coastal sediment that has been cemented primarily by calcium carbonate within the intertidal zone in tropical and subtropical regions. Considering that beachrock has the potential to inhibit coastal erosion, we performed laboratory tests to understand the formation mechanism of beachrocks in southern coastal regions of Sri Lanka. The mineralogical composition of beachrock samples were identified by FT-IR spectroscopic technique. The constituents of minerals present in the beachrocks were further confirmed by XRD analysis. Elemental concentrations of beachrock samples have been examined using WD-XRF spectrometry. The formative environment (sea water) was analyzed using EDTA titration, AAS, UV/Vis spectroscopy and Iron Chromatography. The results reveal the presence of minerals aragonite, calcite, orthoclase, quartz, albite, kaolinite and lime in the beachrocks. According to the results, there is a high probability to precipitate CaCO3 from the sea water in southern coastal regions indicating a positive formative environment for beachrocks. Hence, by appropriate regulation of the conditions could foster the development of manmade beachrocks to control the coastal erosion.
item: Conference-Full-text
GIS-based analysis of coastal vulnerability in southern province of Sri Lanka: insights from Matara district coastal area
(Department of Earth Resources Engineering, 2023-08-28) Ratnayake, KM; Edirisooriya, KVUI; Rubasinghe, DM
Coastal erosion is a substantial natural hazard that is affecting both the environment and human communities globally. Sri Lanka's coastline is about 1600 kilometres, with rich biodiversity and resources, and faces growing coastal erosion, notably in the southern coastal region especially in the Matara District. Therefore, understanding the causes and effects of coastal erosion is essential. This study aims to evaluate shoreline changes from 2000 to 2020 (Weligama to Dikwella) and involves three stages such as mapping shoreline changes using satellite data (Landsat) a digital shoreline analysis system (DSAS), statistical analysis for shoreline changes rates over 20 years, identifying interplay between factors. DSAS measures shoreline changes using baseline approaches and results are presented for both northeast monsoon (NEM) and southwest monsoon (SWM) seasons. NEM shows coastal accretion in Matara due to sediment transportation, while SWM reveals erosion in Devinuwara through strong waves and sediment movement. Sea level rise, rainfall, and river flow correlations influence erosion patterns. Overall, this study emphasizes the use of advanced technology to understand and monitor coastal erosion, help decision-making and develop effective strategies for protecting coastlines.