Thursday, Aug 05, 2004
Thursday, Aug 05, 2004 |
| Kerala | ||||
|
News:
Front Page |
National |
Tamil Nadu |
Andhra Pradesh |
Karnataka |
Kerala |
New Delhi |
Other States |
International |
Opinion |
Business |
Sport |
Miscellaneous |
Advts: Classifieds | Employment | Obituary | Kerala
By P. Venugopal
THIRUVANANTHAPURAM, AUG. 4. The frequent incidents of landslips in the Western Ghat regions of the State can be directly attributed to degradation of natural vegetation and wrong land use practices, according to geoscientists. The Centre for Earth Science Studies (CESS) in Thiruvananthapuram has been conducting a post-mortem study of such incidents in the State over the last more than one decade. According to CESS scientist, G. Sankar, 90 per cent of these incidents occurred in the border areas of the plateau of the Ghats. The vulnerable areas of the Ghats stretch over a length of nearly 500 km in the State, with an average width of 3 km. Thus an extent of nearly 1,500 sq. km. in the State is prone to landslips. Massive landslips of the type that occurs in the Himalayan Ranges do not occur in Kerala because the rocks that make the hills of the Western Ghats are harder than those of the Himalayas. The State witnesses the `debris flow type of landslips', with the top soil mass and withered surface rocks sliding down the hills during times of high intensity rainfall.
Degradation
Natural vegetation, with the huge trees sending their roots to the fissures of the underground rocks to provide cohesion to the landmass, will rule out landslips. But, the problem in the areas identified as prone to landslips is that the natural vegetation had disappeared. Contour bunding, terracing of steep slopes and blocking natural drainage channels (which may not be visible outwardly) lead to the formation of sub-surface reservoirs during heavy rainfall. When the stress exceeds a limit, the result will be landslip and disaster, Mr. Sankar says. The incident that occurred in Kulamavu today is a typical example, though it cannot be termed a landslip in the usual sense. According to reports, the tragedy in Kulamavu was a man-made one, with a check dam constructed on a slope giving in due to the pressure built up by the inflow of water received during heavy rains. According to Mr. Sankar, a majority of the landslips that had occurred in the State in the past were in terrains with slopes ranging from 25 degrees to 32 degrees. Slopes of more than 16 degrees are found to be landslip-prone in the Ghat areas of the State.
Precautionary measures
The CESS, based on its studies, had suggested to the Government a series of precautionary measures to prevent loss of lives and destruction of property due to landslides. The first suggestion is that critical zones should be clearly demarcated and freed of settlements, if necessary, by force of legislation. "Whenever alterations are made to slopes, with contour bunding, terracing or construction of roads, adequate provision should be made for storm water drainage. This is often neglected. Also, degraded natural vegetation at the top of the slopes increases the chances of landslips. Reforestation has to be taken up in such places. Planting slopes with tuber crops etc., whose roots do not run deep, is to be avoided.
Printer friendly
page
News:
Front Page |
National |
Tamil Nadu |
Andhra Pradesh |
Karnataka |
Kerala |
New Delhi |
Other States |
International |
Opinion |
Business |
Sport |
Miscellaneous |
|
|
|
The Hindu Group: Home | About Us | Copyright | Archives | Contacts | Subscription Group Sites: The Hindu | Business Line | The Sportstar | Frontline | The Hindu eBooks | Home |
Copyright © 2004, The
Hindu. Republication or redissemination of the contents of
this screen are expressly prohibited without the written consent of
The Hindu
|
