FLOOD & EROSION MANAGEMENT-LONG TERM MEASURES IN ASSAM

FLOOD & EROSION MANAGEMENT-LONG TERM MEASURES IN ASSAM

Assam is prone to various calamities like earthquake, drought, cyclone storm, cloudburst, land slide, etc. Apart from human untold human misery, recurrence of flood almost every year has ravaged the state economy. The problem has been further aggravated by large scale erosion by the Brahmaputra and its tributaries .The state covers an area of 78,438 Sq. kms. Which consist of the Brahmaputra valley, the Barak valley and two hill districts. The Brahmaputra and the Barak are the two main rivers in Assam. The Brahmaputra has 47 major tributaries and 126 sub-tributaries. The Barak has 20 major tributaries of which 11 are in India. The Brahmaputra is a unique river in the world in that it has a huge catchments area and it has one of the highest water discharge rates. But it has to pass through a narrow U-shaped valley in Assam. While the average width of the river is 6 to 10 kms in Assam, the average width of the Assam valley is only 80 to 90 kms. Before it enters Assam the slope of the river is very steep.

As already mentioned erosion is the other major problem. Because of erosion the width of the Brahmaputra has increased by about 60%. The average width of the river has increased from less than 6 kms in 1910 to more than 9kms today. At the time of the first survey (1912-28) the river covered and area of 3,870 sq kms. On the average 3500 hectares of the land is being eroded by the river annually. In the state as a whole total area eroded by the Brahmaputra, Barak and their tributaries since 1954 is 4,25,000 ha (4250 Sq. KM) which constitute 7.4% of the total area of the state. So far 4521 villages have been eroded effecting 890,000 families. Some towns, tea gardens and heritage site have also been eroded. Even by conservative estimates the present value of the eroded land will be Rs. 40,000 Crores. Because of its horizontal expansion over the years today 130 reaches are classified as seriously effected and 25 reaches are extremely vulnerable due to acute and unabated erosion.     

Since independence and specially after the unprecedented floods of 1954, the Government of India had constituted several committees to study the problem of floods in the country in general or specifically in the Brahmaputra valley. The important such committees which went into the flood problem were: High Level Committee on Floods - 1957, Ministers’ Committee on Flood Control -1964, The Ministers’ Committee on Flood and Flood Relief – 1972. The Govt. of Assam also constituted some Committees to study the problem of floods in the Brahmaputra valley.

Unfortunately here in Assam only short term measures of raising embankment along the river have been implemented so far, and that too partially. The medium and long term measures of drainage channel, Channel improvement and construction of storage reservoirs remain unimplemented for the last 54years. 93.56% of the total embankment length is almost 40 year old. They have completely outlived their strength and normal life span. Breaches of these old and weak embankments have become a feature even in a low to medium intensity flood. But the frightening reality is that, not to talk about thousand of villages, even some important town like, Dibrugarh, Jorhat and Sibsagar will cease to exist without the embankments. Hence long term measures are a must for very existence of the state of Assam.