|What is flood and how this occur:-|
As like as the other calamities, Flood is the most devastating natural calamity that effects Assam every year. Brahmaputra and Barak are the majore rivers in Assam, River Brahmaputra flows through the Brahmaputra valley length 720 kms (over 35 tributeries) And river Barak flows through the Barak valley (over 7 tributeries) which causes the devastating flood claiming damages to public property, living being and environment. Assam is sorrounded by Hills on the almost all sides, what is the primary reason behind the regularbfloods in the state. Howover, Flood in Assam is caused by a combination of several natural and anthropogenic factores. In the month May to September rainfalls in Assam heavy. Moreover, the catchment areas are much higher which fueled the flood dangerously. Experts have identified various factor that creat conditions conductive to floods. To be specific, we can pinpoint several causes:-
Brahmaputra is a big river of Assam and all valleys of Assam consists of friable rock and siltyearth. . These sediments raise the bottom of rivers and thus, 'geological process' canot be stopped and causes an important factors of flood.
Destruction of wetlands and filling-up of the natural catchment areas have also added to the fury of floods. Unscientific land treatment along with unplanned development scheme in the natural catchment drainage and causing soil erosion, closedthe drainage system.
Human occupation on the flood plains, railway embankments, unplanned roads road -all these anthropogenic activities also contribute to the worsening flood scenario.
Effects of flood in Assam :-
The effects of flood are diverse and manifold which effects on land , roads, and others eans of communication, water, forests, wildlife, beels, agriculture livestock and all these leading to diverse effects on biodiversity, ecology and environment. Of course, the frequency of flood having various in various years-causes varried effects and degree of damages also various. As the example in 1988 the annual lose due to flood was 663.88 crores on the otherhand in 1989 there was no major loses due to flood. However , the main effects can be sumerised in the following ways:-
For the first we can pinpoint the effect of flood in Assam as damages to agricultural productivity. Soil erosion and degradation of land and water leads to damage of the production base, thus adversely affecting the sustainable agriculture as well as development. The 'sali pady' is planted in July/August which matured within 15th of september. If the flood does not last long then there may be hope of replanting the damaged crops with new seeds.
For the second, flood also damaged the soil-adversely in three ways- (a) Sand and silt carried by flood covers the fertile fields (b) Sudden flow of water with rapid current may also wash surface soil alongwith nutrients from the field (c)Heavy rain inthe scanty land areas thus causing soil erosio. All these, in a body, often made the field unfit for cultivation.
For the third, foods also leads to the damage of irrigation channels. The irrigation-channels in the flood prove areas either damaged or covered with soil.
For the rourth, large scale damages are seen on the live-stock and population. Heavy floods washway and kill the live-stocks such as domestic and wild animals with forests. Several live-stock also die due to starvation during floods. Various diseases also attack these after flood. People are also affeced by floods in various ways such as washed way or attacked by diseases after flood.
At last flood also damages bio-diversity and ecology, Sedimentation and deposition of silt and sand affects the bills, wetland, natural drainage, fish migratory birds, crops, forests, animals, air pollution resulted from deadbodies of livestocks etc. All these in a body damages the bio-diversity and harms the balanced ecology. Moreover, flood also damaged the grazing fields and creats problems for the animals just after the flood. In this context we can reflect on the recent past flood of 2004, which affected about 1 crore 22 lakhs people who lost their houses and crops for nex six months causing death of 251 people. This flood also caused destruction of roads, agriculture, forests, live-stocks etc.