Lessons from a deluge3 min read . Updated: 12 Oct 2009, 10:34 PM IST
Lessons from a deluge
Lessons from a deluge
Let’s begin with a disclaimer that no individual weather event, such as the one that submerged parts of Andhra Pradesh and Karnataka this month, could be attributed to global warming. The big rise in global temperature probably won’t take place until the second half of this century, but the tragedy is that, thanks to our dams and reservoirs, there will still be plenty of non-climate-change-induced damage.
The likes of the 600% higher rain that caused the deadly floods in south India have reportedly become 10% more frequent in the last decade. But preparedness for such events has remained inadequate, notwithstanding similar floods in Gujarat (2005) and Bihar (2008). As fresh disasters charter unfamiliar territories at a fiery pace, the National Disaster Management Authority (NDMA) has failed to get its act together.
That traditionally water-deficit regions in the Deccan plains registered a water surplus in one fortnight can be partly attributed to the story of low-pressure areas across the Bay of Bengal. The significant other part relates to the bickering for decades over rights to the Krishna river, resulting in Andhra Pradesh and upstream Maharashtra and Karnataka furiously building dams and diversions to hold a larger share of the river water. While the Koyna dam exists on the Krishna in Maharashtra, Karnataka has the Almatti and Narayanpur storage structures across the river. The overflowing Srisailam dam during the recent floods and the tallest Nagarjuna Sagar dam, too, exist on it in Andhra Pradesh. Even the Tungabhadra tributary of the Krishna has not been allowed to flow freely—the dam on it is a joint initiative of Karnataka and Maharashtra.
Built with the twin objective of producing hydropower and irrigating farmlands, each of the large dams in the country has failed to provide flood protection to downstream populations. It was no different during the recent floods: Excess inflow from the Almatti reservoir caused the Srisailam dam to overflow, inundating as many as 50 downstream villages, for no fault of theirs. Far from providing protection, structural flood-control measures have enhanced vulnerability.
Dam authorities are compelled to hold as much water in the reservoir as possible, to meet the dual objective of generating power and meeting demands for irrigation. Any unexpected upstream recharge would result in unwarranted downstream release of excess water. The Srisailam dam could handle only 1 million cusecs (cu. ft per second) of water, whereas the inflow during the ill-fated week was in excess of 2.2 million cusecs. The storage capacity of most dams has gradually reduced on account of silt deposition.
States often seek flood relief by addressing the symptoms and not correcting the systems, measures which end up enhancing the vulnerability of downstream populations. No surprise then that human misery continues to grab headlines while the cause-effect relationship of disasters skips careful diagnosis.
To draw attention to such lapses, the Telangana Rashtra Samithi, a political party, has attributed the recent floods to human follies than nature’s fury. It has further been alleged that the irrigation projects have been politically motivated to benefit vested interests. Prophetic as it may sound, Peter Salberg, a British engineer, had informed the historic Patna Flood Conference in 1937 that the “skills of engineers and resources of governments have often played havoc with people".
No lessons seem to have been learnt. Consider that for releasing flood waters from the Bhakra dam, the chairperson of the Bhakra-Beas Management Board was allegedly shot dead during the peak of the insurgency in Punjab. We don’t want that history to repeat itself. Given the decrepitude of much of the existing water infrastructure and profligate ways with water, it’s urgent for NDMA to develop a vulnerability index to measure the impact on the unsuspecting communities before such projects are given approval.
Sudhirendar Sharma is a water expert at the New Delhi-based Ecological Foundation. Comment at email@example.com