Browsing by Author "Nianthi, K.W.G.R."

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    Evaluation of Rain Drop Project Introduced for Chronic Kidney Disease Uncertain Etiology (CKDu) Patients in Ginnoruwa, Mahiyanganaya
    (Uva Wellassa University of Sri Lanka, 2018) Elladeniya, N.C.; Madhushan, K.P.S.; Nanayakkara, N.; Abeysekara, D.T.D.J.; Nianthi, K.W.G.R.
    CKDu is a serious medical problem in the Dry Zone of Sri Lanka. There is an increasing trend for kidney patients in Ginnoruwa GN division of Mahiyanganaya in the recent past. Badulupura is one of the villages in this division where high prevalence of CKDu has been recorded. Since fresh water supply is limited to this area, a Rain Drop Project was introduced in 2015 for CKDu affected families. The project had supported families with 5000-liter water tanks and other utilities. This study has been conducted to assess the outcome of this activity after a period of one-year. The main objective of this study was to reveal the perception of patients on drinking of rain water in terms of the changes of symptoms and future expectations of the patients. A questionnaire based survey, direct observations, and focused group interview with doctors, villagers, and hydrologists were performed to gather primary data and information. Of the respondents, 92% were living in this area for more than 30 years and 72% were paddy farmers. 40% of patients have mentioned that they believe unsafe water is one of the reasons of CKDu. Before the project only 32% patients knew that the rain water is suitable for drinking purposes. Prior to this project, patient used well water for daily consumption and among them 64% used filter or boiled water before consumption while 36% used well water without any purification. 60% patients had the perception that the rain water is natural and it will indirectly supports to control their CKDu. The study also revealed that some symptoms of CKDu patients like burning sensation of urine have been decreased significantly after drinking rain water. 64% patients stated that before the project they used well water and had the symptoms of dark color of their urine and after the project when they use rain drop water the urine color has been changed to pale. At present, 100% of the patients use rain water for drinking purposes. Most of the villagers agreed that this project is useful and successful. Families should be encouraged to use the rain water for their daily consumption which also one of the adaptation practices for the water scarcity in the study area. Providing of good quality water for one year period is not sufficient to assess any biochemical improvement of renal function. It is necessary to conduct future assessment on this issue to come for the concrete indication.
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    Rainfall and Flood Events in the Deduruoya Basin in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2021) Wanninayake, W.M.S.B.; Nianthi, K.W.G.R.; Banda, O.G.D.
    Disaster risk reduction of vulnerable communities is a requirement for the well-being of society. Among many natural disasters, the flood can be identified as the most frequent and threatening disaster in Sri Lanka. A proper study of the relationship between rainfall and flood within the Deduruoya basin has not yet been conducted, therefore it is essential in flood risk management. This study aimed to find the trend of rainfall and the relationship between rainfall and flood in the Deduruoya basin. A time series analysis was employed to find the trend of rainfall using the R software. The Mann-Kendall test and Sen‟s Slope estimate were used for trend detection. A correlation analysis was performed to find the relationship between flood and rainfall. The study was conducted from 1960 to 2019. A significant decreasing trend of monthly mean rainfall was observed in the basin as a whole during the study period. The average monthly rainfall was 140 mm in 1960 and it was decreased to 120 mm by 1985 and further decreased to 108 mm in 2019. The overall reduction of the monthly mean rainfall was 32 mm over the 60 years. This was confirmed by the Mann Kendall test with the P = 0.01 confirming a significant trend. As per the tau value of the MK test, it was reported as -0.06 confirming the overall decreasing trend. The Sen‟s Slope estimate has also confirmed the result (-0.03). 23 flood events were identified in the Deduruoya basin from 1978 to 2020. Eleven flood events (48%) have been occurred in the Second Inter Monsoon (SIM), 07 (30%) events have been occurred in the North East Monsoon (NEM) and 05 flood events (22%) were occurred in South West Monsoon (SWM). No floods have been reported in First Inter Monsoon (FIM) season from March to April. The study revealed that the SIM and NEM seasons‟ rainfall has a strong relationship with floods (78% floods). The findings will be important for flood risk reduction in the Deduruoya basin. Keywords: Rainfall trend; Flood pattern; Flood risk; Relationship between rainfall and floods; Deduruoya basin
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    Rainfall Variations in Kandy District of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2018) Meegahakotuwa, U.S.; Nianthi, K.W.G.R.
    Rainfall of Sri Lanka is of multiple origins, including monsoonal, convectional and depression. In the rainfall calendar of Sri Lanka, four rainfall seasons have been recognized. They are the First Inter-Monsoon (FIM), South West Monsoon (SWM), Second Inter-Monsoon (SIM) and North East Monsoon (NEM). Rainfall variability over space and time must be regarded as the most significant aspect of the monsoon climate over Sri Lanka. The main objective of this study was to identify the spatial distribution of annual and seasonal rainfall in Kandy District (KD). The monthly rainfall data have been collected from 19 rainfall stations in KD from 2005 to 2014. The data were obtained from the Department of Meteorology and other relevant institutions. Spatial interpolation was done to prepare the isohyet maps for KD using Radial Basis Functions Method in ArcGIS 10.2. The analysis shows that the highest annual average rainfall (5,660 mm) has been recorded at Galamuduna Estate in Dolosbage, and the lowest is recorded at Kundasale (1,594 mm) during the study period. From 2001 to 2014 the Galamuduna annual average rainfall was 5,176 mm. According to the seasonal rainfall, during the FIM period (March-April) the rainfall varies from 700 mm (Craighead Estate) to 241 mm (Minipe). Rainfall during SWM period (May to September) varied from 3,436 mm at Galamuduna to 174 mm at Minipe. The southwestern windward side received the highest rainfall while the Eastern leeward side received the lowest during SWM season. The Galamuduna Estate is situated in highest rainfall region of Wet Zone Up-Country of Sri Lanka. The SIM period (October to November) showed most evenly distributed rainfall over the Kandy District. During the NEM period in December to February, the highest rainfall was recorded in the Eastern side of the KD. The highest rainfall (700 mm-1,000 mm) is recorded in and around Minipe station during this season. Kandy Plateau area received a lower rainfall in the NEM season. The study revealed that the annual and seasonal distribution of rainfall over Kandy District has considerable differences. Based on the annual average rainfall, the wettest place of the Kandy District was the Galamuduna Estate and the driest places were recorded as Kundasale and Minipe. The month of June was recorded as the wettest month (777 mm) in Galamuduna and the same month, Minipe (5 mm) was noticed as the driest during the study period.
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    Seasonal Solar Power Generation Potential for Electricity Supply in the Dry Zone of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2019-02) Meegahakotuwa, U.S.; Nianthi, K.W.G.R.; Dissanayake, D.M.
    Solar radiation is an important climate element and the largest energy input in the world. Sri Lanka is largely dependent on thermal energy and hydropower for its electricity needs. The solar radiation is the most abundant natural energy and it has great potential to meet the energy requirement of Sri Lanka. Solar-powered photovoltaic (PV) panels convert the sun's rays into electricity by exciting electrons in silicon cells using the photons of light from the sun. Being located close to the equator with the benefit of having sunlight for more than 12 hours per day, using solar systems to generate electricity is truly beneficial for the country. The main objective of this study was to calculate the seasonal solar radiation flux in the Dry Zone of Sri Lanka. The daily solar radiation data was collected by the Silicon Pyranometer for the period from July 2009 to June 2010 from the automatic weather station at Mahailuppallama Agro-Meteorological station. According to the daily average figures, the lowest average daily solar irradiance of 12.6 MJ m-2 was received in the month of December, whereas the highest average daily irradiance of 21.7 MJ m-2 was received in the month of March. According to the seasonal records, the highest solar radiation of 21.4 MJ m-2 received during the First Inter-Monsoon period from March to April and in the South West Monsoon from May to September shows also reasonably high solar radiation of 19.3 MJ m-2, because this period, the airflow generally flows from southwest to northeast direction with less moisture to the Dry Zone. The Second InterMonsoon from October to November, solar radiation was recorded as 17.0 MJ m-2 and in the North East Monsoon period from December to February, the solar radiation was recorded as 16.6 MJ m-2. North East Monson is a climatologically rainy season in the Dry Zone because incoming solar radiation and rainfall are associated with low solar insolation. The study shows that there is a high potential for solar power generation in the Dry Zone of Sri Lanka. The establishment of the solar power plants in the Dry Zone can make a significant contribution to the National Grid of Sri Lanka.
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    Spatial and Temporal Variation of Temperature Trends in Last Century of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2018) Meegahakotuwa, U.S.; Nianthi, K.W.G.R.
    The climate of Sri Lanka is characterized as tropical monsoonal. Temperature is one of the main elements in the tropical climate. Spatial differences observed in air temperature over Sri Lanka are mainly due to altitude, rather than latitude. The mean annual temperatures in Sri Lanka manifest largely homogeneous temperatures in the lowlands and rapidly decrease with altitude towards the Central Highlands. The mean annual temperature varies from 27 °C in the Coastal Lowlands to 16 °C at Nuwaraeliya (1900 m) in the Central Highlands. The objective of this study was to examine the spatial variation of temperature trends of Sri Lanka in the last century. The study was based on mean annual temperature data for the period from 1916 to 2015 at 15 meteorological stations distributed all over the island. The data were obtained from the Department of Meteorology, Colombo. The temperature trends over the last 100-year period were estimated using the Linear Regression analysis. The Mann-Kendall statistical test was applied to identify significant or non-significant monotonic trends. Spatial interpolation was done to prepare the temperature trend map for whole Sri Lanka using Radial Basis Functions Method in ArcGIS 10.2. The results revealed that, the trends of mean annual temperatures have been increasing in all meteorological stations. Out of the 15 stations, 13 displayed statistically significant (P < 0.0001) increasing trends. The rate of the increment annual temperature for the 1916 - 2015 period was in the order of 0.009 °C per year (0.9 °C per century) in Sri Lanka. The highest increasing trends were noticed in and around Anuradhapura, i.e. 0.016 °C per year. Two other increasing trends were noticed in two clusters, one in Nuwaraeliya in the Central Highlands and another in Colombo in Western Coastal Lowlands. Mean annual temperature increment was higher in Dry Zone (0.01 °C per year) than that of the other two zones, i.e. Wet and Intermediate. The trend value of Intermediate Zone was 0.009 °C per year and the Wet Zone value was 0.008 °C per year. Reasons for the increase of temperature in Sri Lanka can possibly be the impact of global warming and the influences from ElNino phenomena. Observed increasing trends of temperature can negatively impact on the human activities and natural environmental processes of Sri Lanka.
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    Variation of Slope Environmental Lapse Rate (SELR) in the Western and Eastern Slopes of the Central Highland in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Meegahakotuwa, U.S.; Nianthi, K.W.G.R.
    The average temperature decrease (6.5°C km-1 ) with increasing elevation in the free atmosphere is generally called as Environmental Lapse Rate (ELR). The Temperature Lapse Rate (TLR) along the mountain slopes significantly differs from the free atmosphere ELR. The TLR along a mountain slope is here termed as the Slope Environmental Lapse Rate (SELR). The main objective of this study was to identify the variation of the SELR in the Western and Eastern slopes of the Central Highland in Sri Lanka during the South-West Monsoon and North-East Monsoon seasons. The seasonal average temperature has been calculated from 2008 to 2017 from three Meteorological stations; Nuwaraeliya (1895 m), Ratnapura-Western slope station (34 m), and BadullaEastern slope station (670 m). Elevation and temperature of the Nuwaraeliya were taken as the base location and calculated the SELR by ((T1-T2)/(H2-H1) *1000) for Ratnapura and Badulla. The result revealed that the SELR is 5.9°C km-1 in the Western slope and 6.5°C km-1 in the Eastern slope of the Central Highland during the South-West monsoon season. The Western side of Central Highland receives more rainfall than the Eastern side when South-West monsoon occurs. During this season the entire area of Eastern slope in the Central Highland gets dry due to the inverse direction of the monsoon with the effect of orography rainfall. During the North-East monsoon season, the SELR is 6.4°C km-1 in the Western slope and 4.9°C km-1 in the Eastern slope due to the stimulating of NorthEast monsoon on the Eastern side. Considerable spatial differences have been noticed during two seasons. The seasonal monsoon rainfall patterns are highly affected for variation of the Slope Environmental Lapse Rate in the Western and Eastern slopes of the Central Highland in Sri Lanka. . Keywords: Central Highland, Eastern slope, Seasons, Slope Environmental Lapse Rate, Western Slope