Browsing by Author "Piyadasa, R.U.K."

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Assessment of environmental impacts due to river sand mining
(University of Kelaniya, 2008) Piyadasa, R.U.K.; Naverathna, C.M.
Forecasting Temporal and Spatial Rainfall and Temperature Trends for Calculating Climate Variables for Land Suitability Evaluation
(Research Centre for Social Sciences, Faculty of Social Sciences, University of Kelaniya, Sri Lanka, 2016) Ranasinghe, G.; Piyadasa, R.U.K.
The principle purpose of land suitability evaluation is to predict the potential and limitation of the land for crop production and other land uses. Therefore, suitability is a function of crop requirements and land characteristics. This study was carried out to predict the temperature and rainfall trends as one of the major factor for evaluating land suitability. For this study, climatic data such as monthly mean temperature, total monthly rainfall, maximum daily rainfall value for each month and total annual rainfall for the last 30 (1986- 2015) consecutive years of three weather stations located in Bentota River basin was collected from Meteorological Department, Sri Lanka. Collected data were analyzed applying time series analysis method, correlation analysis and Manna Kendall trend test method. Forecasted and actual spatial and temporal rainfall distribution pattern was illustrated applying inverse distance weighted tool in Arc GIS software and XLSTAT software. The main findings revealed that monthly mean temperature and maximum daily rainfall value for each month had a general increasing trend whereas, total monthly rainfall and total annual rainfall showed a general decreasing trend in Bentota River basin. Analysis of the 30 years total monthly rainfall data from three representative ground based meteorological stations indicated relatively high rainfall situations during May and October while low rainfall situations during January and February by highlighting the extreme variability of rainfall once per five years during any month from April to November making flood situation in the area. To conclude, development planners and agricultural scientists should evaluate land suitability of Bentota River basin area by taking into account a declining rainfall and increasing temperature impacts in the context of climate change.
Groundwater potential assessment after the tsunami destruction in southern coastal belt of Matara district, Sri Lanka
(National Aquatic Resources Research and Development Agency, 2007) Piyadasa, R.U.K.; Weerasinghe, K.D.N.; Liyanage, J.A.; Wijayawardhane, L.M.J.R.; Priyantha, S.M.P.D.; Konara, S.
Physiochemical characteristics of ground water in out-skirt of Tsunami affected area; case study in Denipitiya, Southern Sri Lanka
(Sabaragamuwa University of Sri Lanka, 2006) Weerasinghe, K.D.N.; Piyadasa, R.U.K.; Wijayawardhana, L.M.J.R.; Liyanage, J.A.
Research study on soil and water quality in ball clay mining areas: with special reference to Dediyawala in Kaluthara district
(University of Kelaniya, 2008) Perera, K.G.N.; Piyadasa, R.U.K.
Soil and groundwater salinity variation in Matara district coastal belt- Sri Lanka
(Sri Lanka Association for the Advancement of Science, 2008) Dharmasena, T.H.Y.; Piyadasa, R.U.K.; Weerasinghe, K.D.N.; Liyanage, J.A.; Weerasinghe, W.A.D.C.S.
The present research study identifies changes in salinity of soil and groundwater in tsunami affected and unaffected areas in Matara district. Within study area a total of 21 auger holes were drilled representing both tsunami affected and non-affected areas. The auger holes were distributed within approx 0.5 to 0.7 km distance from the coastline. Auger holes are selected to maintain perpendicular transacts to the coastal line. From each auger point, soil samples were taken from the surface layer and followed by each 50 cm depth until groundwater table is reached. Groundwater samples were also taken from auger holes and from dug wells near to auger holes. Soil physical parameters such as specific gravity, soil moisture, were determined. Soil chemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS) and salinity were measured using pH and EC meters. The electrical conductivity (EC) of the soil in the tsunami affected area varied from 100 μS /cm to 422 μS/cm and groundwater salinity changed in between 400 to 2000 μS /cm. A direct relationship between EC and soil depth was detected. The prepared maps confirm that soil salinity, pH and EC variations were directly related with groundwater salinity. Additional salinity levels are related with morphological factors and soil physical parameters.
Soil erosion intensity due to different land use patterns in Nuwara – Eliya district, Sri Lanka
(University of Kelaniya, 2008) Amali, M.K.A.A.; Piyadasa, R.U.K.