Changes in Rainfall in Sri Lanka during 1966 – 2015

Karunathilaka, K. L. A. A.; Dabare, H. K. V.; Nandalal, K. D. W.

doi:10.4038/engineer.v50i2.7251

Cited by 30 publications

(39 citation statements)

References 6 publications

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“…Similar to the above findings, Karunathilaka et al, (2017) in their study revealed that the eastern region of the country has shown an increasing trend in rainfall over the last half century, while western, northern and south-western region and central hill of the country have shown a decreasing rainfall trend during the same period. As like the annual total rainfall monthly and seasonal rainfall also show an important pattern in this district.…”

Section: Fig 1: Annual Total Rainfall From 1918 -2017supporting

confidence: 82%

“…These two prime monsoons (South-West and North-East Monsoons) are responsible for distinct cropping seasons known as Yala and Maha. Karunathilaka et al, (2017) emphasizes that, the seasonal rainfall indicates an increasing trend during the first-inter monsoon, second-inter monsoon and north-east monsoon seasons at a majority of the stations.…”

Section: Introductionmentioning

confidence: 78%

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A Statistical Analysis of Rainfall Variability and Paddy Production Trend in Batticaloa District, Sri Lanka

Selvanayagam¹

2018

IJAES

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Paddy production, in the district of Batticaloa, in Sri Lanka, experienced severe challenges due to the rainfall variability in the recent past. The main objective of this paper is to assess the rainfall variability and to identify the relationship between paddy production and rainfall, by means of statistical analysis. Rainfall variability was analyzed using the data of 100 years from 1918 to 2017, of Batticaloa district and the relationship of variables was identified using the data of 40 years from 1978 to 2017. This study adopted a trend analysis using nonparametric and parametric econometric techniques to evaluate the relationship between paddy production and rainfall using EViews 9.0 software. The model was evaluated using Ordinary Least Square (OLS) technique. Results revealed that the annual and seasonal rainfall showing a significant increasing trend. After 1957, rainfall had fluctuated with high variability and rainfall intensity had increased in some years, resulting in flood hazard. On the other hand, dry weather had resulted in long drought condition. Based on the regression results, positive relationship between rainfall and paddy production in Maha season was identified and it is also statistically significant at 1% confidence level. A unit increases in the rainfall in Maha season would increase the paddy production by 0.05 times. Moreover, the rainfall in Yala season negatively correlated with paddy production in Batticaloa. However, it is not statistically significant.

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Section: Fig 1: Annual Total Rainfall From 1918 -2017supporting

confidence: 82%

Section: Introductionmentioning

confidence: 78%

A Statistical Analysis of Rainfall Variability and Paddy Production Trend in Batticaloa District, Sri Lanka

Selvanayagam¹

2018

IJAES

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“…Ratnapura district is in wet zone of the country. This area is highly vulnerable to frequent flooding due to higher rainfall volumes (Eriyagama et al 2010;Karunathilaka et al 2017). Rathnapura district receives a significant rainfall from SW monsoon from May to September (Punyawardena and Cherry 1999).…”

Section: Case Study Application-erathna Mini-hydropower Plantmentioning

confidence: 99%

“…However, they found that the intensity of rainfall was increasing. In addition, Ranatunge et al (2003), Jayawardene et al (2005), Wickramagamage (2016) and Karunathilaka et al (2017) have put efforts in studying annual and seasonal rainfall trends in Sri Lanka. (Khaniya et al 2018) presented some interesting rainfall trend analyses and linked them with the hydropower generation of a ROR hydropower plant.…”

Section: Introductionmentioning

confidence: 99%

Impact of climate variability on hydropower generation in an un-gauged catchment: Erathna run-of-the-river hydropower plant, Sri Lanka

Perera¹,

Rathnayake

2019

Appl Water Sci

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Impact of climate change or climate variability on water resources is an exceedingly concerned issue. Hydropower development is one of the most affected industries due to the climatic variability. Therefore, this paper presents the promising results from a study of the impact of climate variability on hydropower generation of Erathna run-of-the-river (ROR) hydropower plant located in Rathnapura district, Sri Lanka. This study was based on surrounded rain gauges outside the catchment as Erathna catchment area is an un-gauged catchment. 30-year rainfall trend analysis from 1988 to 2017 was done using Mann-Kendall and Sen's slope estimator tests to predict the available trends. Pearson's correlation coefficient was used to investigate the relationship between rainfall and Erathna power generation. Results show negative trends for annual rainfalls in several rain gauges, while seasonal trend analyses support that observation. July is the most critical month for most of the rain gauges around the catchment. The results also show a good correlation between the rainfalls and power generation. Therefore, the results conclude the importance of rainfall trend analysis in un-gauged catchments and its forecasting capacity of water resources usage in hydropower development.

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“…However, around two-day continues 75 -100 mm rainfall can trigger landslides in sloped cultivated lands in Badulla [22]. In Sri Lanka, an increasing trend in high intense rainfall event during last decade is recorded, especially in the Wet Zone and western slopes in the central hills [23]. Also, the frequency of landslide events per year has increased over the last few decades.…”

Section: Introductionmentioning

confidence: 99%

A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka

Perera¹,

Jayawardana²,

Jayasinghe³

2017

GEP

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Mass movement in Sri Lanka is mainly triggered by heavy rainfall. International literature is rich of works defining rainfall intensity-duration models to identify the rainfall threshold for various types of Mass movement. However, studies have not focused to establish a relationship between intensity and duration of rainfall in Sri Lanka. Therefore, this study focused to establish rainfall intensity-duration models to identify the rainfall threshold for mass movements in Badulla district in Sri Lanka, where forty four (44) rainfall events that resulted in same number of landslides during the last three decades were considered. Results indicate the rainfall threshold relationship fits to the log linear model of the exponential function, I = α·D −β . The constructed I-D curve revealed that short duration (<2 h) and high-intensity (>54 mm/h) in rainfall events can potentially trigger the landslide. However, long-duration (>8 h) and low-intensity (<25 mm/h) in rainfall events may also trigger mass movements in Badulla. As per the results, most mass movements occur during northeast monsoons and inter-monsoons. In general, higher mean rainfall intensities trigger the debris flows, while long-duration rainfall events can trigger both landslides and debris flow. When compared to Sri Lankan mass movements triggering threshold intensities are fairly higher than the global threshold values. It confirms that within Badulla, mass movements are triggered by very high intense and/or long duration rainfalls events only. Further, time series analysis of the rainfall events shows an upward trend of extreme rainfall events, which increased landslide occurring frequency in last six (6) years.

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Changes in Rainfall in Sri Lanka during 1966 – 2015

Cited by 30 publications

References 6 publications

A Statistical Analysis of Rainfall Variability and Paddy Production Trend in Batticaloa District, Sri Lanka

A Statistical Analysis of Rainfall Variability and Paddy Production Trend in Batticaloa District, Sri Lanka

Impact of climate variability on hydropower generation in an un-gauged catchment: Erathna run-of-the-river hydropower plant, Sri Lanka

A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka

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