Abstract:
Rainfall in Sri Lanka is very heavy, as it is located in the tropical zone of the Earth. Due
to the heavy rain, people have to face many natural disasters mainly flood. At present,
Physical and human environment has been damaged due to flash flood. It has caused a
huge impact. The main objective of the study is to explore the factors that affected in
rapid flash flooding in the mountain areas in Sri Lanka. The study area of this research
is NalandaOya catchment in Matale District. This study based on primary and secondary
data. Questioners, observation and semi structured interviews have been used as collect
primary data. Also secondary data collected using institutional data, research papers,
articles, internet and books. The collected data was analyzed using both qualitative and
quantitative methods;and quantitative data was presented under simple statistical analysis
to using “Ms Excel” software. Also descriptive method uses to analyze qualitative data.
Also scientific data were analyzed using geographical information system. According to
the study it was prove that, there are many physical and Socio-economic factors affected to
improve the flash flood in mountain areas. Especially temporal changes of rainfall pattern
and relief features are caused to recurring flash flood. Also socio-economic activities like
encroaching reservation, failures of construction road and bridges, invasion of invasive
plant and sand mining in river bed are helped to improve flash flood. Therefore, the research
suggestion is should be taken action for unauthorized encroaching, failures of development,
minimize the sand mining and controlling invasive species. Also create a successful
Community Preparedness mechanism and successful community pre-preparedness plan
related to flash flood.
