QUANTITATIVE AND GIS BASED TREND ANALYSIS OF CLIMATIC VARIABLES AND FLASH FLOOD EXTENT IN THE NORTH-EASTERN HAOR REGION, BANGLADESH

This study was carried out to analyze the pattern of the changes in temperature, rainfall, and the frequency and intensity of flash floods in the Haor districts of north-eastern Bangladesh over decadal scale periods. Regression models predicted a slow but gradual rise of maximum temperature to the extent of about 1.06-1.94% per decade which might pose significant threats to the agriculture and fisheries productions over a longer time. Models predicted an average increase of 4.1% and 2.28% of the annual rainfall in Sreemangal and Sylhet stations, respectively. A relatively lower peak river stage was noticed for the tidal rivers compared to the non-tidal rivers within a fifty-years return cycle. Frequency analysis results indicated high chances of short term extreme flood events at most of the river stations within a fifty-years return period. Geospatial analysis results showed a time dependent variations of peak flood extents at different locations within the study area. Results indicated that the frequency of flash flood has not increased in the past fifty years but the intensity of flood has noticeably increased during the recent decades in several haor districts which might increase the likelihood of the losses of agriculture and fisheries production in those areas.