Floods are one of the most common natural disasters leading to economic losses and loss of human lives(D. D.
Alexakis, 2004).As monsoon rain kept on pouring and overflowing the rivers in the country as wellas the upstream hilly regions of neighbouring countries, Bangladesh faces flood affecting the northern,north-eastern and central part of the country. Naogaon District is a mostly affected one in northern part(Society, 2017). Naogaon district has 10 rivers (Atrai River, Punarbhaba River, Little Jamuna River, GurRiver, Dhol River or Dhol Sea, Tulshiganga River, Nagor River, Noor River, Fokinni River, Shiva River)(Kadiyali, 1991). These rivers overflow and causes flood and damage a huge property. Recently (in 2017)heavy floods have severely damaged properties valued around Tk 300 crore in two upazilas of Naogoandistrict following the collapse of a flood control embankment at Mirpur area under Atrai upazila in thedistrict.
Floods have damaged about 23,000 houses, including 7,000 mud huts, worth around Tk 50 crorein Atrai and Raninagar upazilas and 97 educational institutes have also been damaged in the two upazilas.The recent floods have destroyed about 80 km of roads and 6.50 km of the flood control embankmentcausing a huge economic loss (Correspondent, 2017). Floods in 2017 damaged at least 50,000 acres of crops and washed away fish in almost 1,000 ponds. Water in the Atrai River has been 214cm above thedanger level, while the Chhoto Jamuna’s level has been 70cm above the danger line(Sadequl Islam, 2017).So, Naogaon District has bad experiences of flood and that is why Naogaon District has been chosen as thestudy area. The study area has experienced a huge amount of changes due to flood during the year between 2004 -2017.For the year of 2004, two Landsat images are taken for analysis purpose.
Figure 3.1 shows the land usechanges for two months in year 2004. In the figure, the image of (a) March 25, 2004 which is taken forshowing the land use conditions before occurring flood and the image of (b) October 19, 2004 is taken forshowing the lands use conditions of during flood.The interpretation of Landsat image (a) represents that the study area was 5.58% of the water body, 7.54%of the built-up area, 59.64% of agricultural and vegetation land and 27.
24% bare soil of 3449.197 sq-kmarea. The data shows only 5.58% of water body existed before an overflow of water. But after increasingthe overflow of water in the month of October, 2004, the percentage of water body represents a massivechange.
The figure 3.1(b) shows the massive changes of water body during the flood which affected allother land uses. The figure represents that the percentage of water body converted from 5.58% to 25.
68%which impacts on all other land uses. Due to an increase of water body, the percentage of built-up area wasalso shifted from 7.54% to 6.70%. Similarly, increasing of water body also effects on agricultural andvegetation land and the percentage was shifted from 59.64% to 48.17% of 3449.197 sq-km lands.