FLOODS IN BANGLADESH

Floods in Bangladesh

Floods in Bangladesh

Introduction

Bangladesh has emerged as the world's most flood -prone country (see Thompson & Sultana, 1996: p. 1). Almost every year floods occur in the country, but the intensity and the magnitude vary from year to year. Long-term time series data indicate that on average 22% of the area of the country is flooded each year, with up to 60% flooded by a 100-year flood ( Haque, 1997: p. 93). During the past 50 years, Bangladesh has experienced 29 major floods, of which 11 were classified as 'devastating' and six as 'most devastating' (see Paul, 1997: p. 121). Floods of 1987, 1988, and 1998 were exceptional both in areal extent and in terms of destruction. As much as two-thirds of Bangladesh was covered by the 1998 flood, which has been deemed 'the flood of the century' ( Ninno, Dorosh, Smith, & Roy, 2001: p. 1).

While river, rainwater, and cyclonic floods in Bangladesh have received attention by researchers, particularly after the devastating floods of 1987 and 1988, no rigorous study has yet been conducted on flooding in the country. This lack of interest is difficult to understand since flooding is not a recent natural phenomenon in Bangladesh and the severity of this form of flooding is increasing over time. Several causes have been identified that trigger and affect the severity of flooding; these are: increased rainfall in upstream areas, a general increased rate of snow melt in mountains due to global warning, and the silting and blockage of the river beds. Another factor that has been lately emphasized as a probable cause for flooding in southeastern coastal areas of Bangladesh are the coastal embankments found there (Brammer, 1990 and Haque, 1997).

Coastal embankment projects in Bangladesh were initiated in the 1960s to increase crop production by preventing intrusion of saline ocean water into crop fields located near the coast. After construction of these embankments, affected coastal areas were beset with many environmental problems. Gradually the effects of these embankments caused drainage congestion due to silt accumulation in tidal rivers and creeks and they also increased salinity in both the soil and water (see Brammer, 1990: p. 15). Congestion has increased the frequency of floods in coastal areas, particularly in the Chokoria thana of the Cox's Bazar district, located along the sea coast ( Fig. 1).

Fig. 1. Location and major physical features of the study area.

The objective of this study is to find out to what extent the coastal embankment is responsible for the increased severity of flooding in the Chokoria thana.

Literature Review

In Bangladesh, flooding is typical in the northeastern and southeastern hilly areas (Fig. 2). Hills in the northeastern region of Bangladesh are bordered by the Himalayan range in the north and the southeastern region is surrounded by extensions of Arakan mountain ranges in the east and the Bay of Bengal in the west. Heavy rainfall in these mountains or excessive snow melt in the Himalayas causes flooding in the southeastern coastal plains of Cox's Bazar and ...