Dam floods · Dams · Floods

Kerala: Dams Floods 2018: Follow Rule Curves to Avoid Flood Disasters

Unprecedented Kerala deluge[1] that swept through the coastal state on the day of Independence day 2018 was most disastrous flood incident in the year. It has also been termed as one the worst flood in the state and reminded the people of July 1924 and July 1962 flood calamities. Many experts, several reports and studies have established the role of dams in worsening the deluge. According to reports, 35 out of the 46 dams within the state were opened for the first time in history[2]. All 5 overflow gates of the Idukki Dam were opened at the same time, for the first time in 26 years.

State Government Accepts Dams Role

Kerala is usually considered a flood-proofed[3] state with its undulating terrain. For a state that receives an annual average rainfall of nearly 3,000 mm, its natural landscape protects it from recurrent floods. Indeed, the Kerala flood has highlighted our poor dam management[4] system. 

As per officials the crisis could have been contained[5] had the state “gradually released” water from at least 30 dams, in advance of high rainfall, adding that local authorities failed to foresee the imminent danger with high rain predictions. “Such floods have probably recurred after 100 years, exposing the State’s unprofessionally run reservoirs management system and unpreparedness on disaster mitigation and disaster resilience.

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Dams · DRP News Bulletin

DRP News Bulletin 15 October 2018: Reuters Corroborates that Dams Played Major Role in Kerala Floods

International news agency, after independent research, have corroborated what SANDRP has been saying: Mismanagement of dams played big role in worsening Kerala floods.

-“The release could have started earlier so that by Aug. 9 there would have been left-over capacities in the reservoirs to store the water,” said Biswajit Mukhopadhyay, director of water resources at U.S-based engineering firm IEA, who analysed some of the publicly available data at the request of Reuters.

– Still, dozens of flood victims interviewed by Reuters, who live in villages dotting the banks of Kerala’s biggest river, the ‎244 km Periyar, say they faced no floods despite torrential rain in late July and early August. All of them said waters only rose overnight on Aug. 15. That was when more intense rainfall forced KSEB to rapidly ramp-up releases of water from Idukki and Idamalayar reservoirs, which feed into the Periyar.

– Kerala’s revenue secretary and head of disaster management, P.H. Kurien, told Reuters he has twice written to KSEB requesting EAPs and has yet to receive them. KSEB’s Pillai said EAPs and dam operation manuals were still being prepared. CWC said it was working with Kerala’s government to speed this up. The Kerala Chief Minister’s office did not respond to requests for comment. https://widerimage.reuters.com/story/did-dams-make-indias-once-in-century-floods-worse  (11 Oct. 2018)

And this fantastic infographic: https://fingfx.thomsonreuters.com/gfx/rngs/INDIA-FLOOD/010080MF18N/index.html  (11 Oct. 2018)

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Dam Induced Flood Disaster · Kerala

Role of dams in Kerala’s 2018 floods

ABSTRACT: Many independent observers have argued that dams have played a role in increasing the proportions of Kerala flood disaster during July-Aug 2018. This article shows that Kerala dams violated many basic norms and if operated prudently, could have helped. It shows how post dam floods are different than pre dam floods. It lists the steps that would help in future disasters involving dams. The lessons are useful for all large dams of India.

In theory, every dam can help moderate floods in the downstream areas, as long as and as much as the dam has space to store water. In fact, every action that helps to store, hold, recharge (to groundwater aquifer), delay flow of rainwater from the catchment to the river would help moderate flow and hence flood in the river. Our catchments are fast losing that capacity, with continued destruction of natural forests, wetlands, local water bodies and also soil’s capacity to hold water. Continue reading “Role of dams in Kerala’s 2018 floods”

Dams

CWC Flood Forecasting: Anomalies between Website and SOP Document

Central Water Commission (CWC) is the only agency in India doing flood forecasting, it becomes very important to understand what CWC does in this regard. The CWC flood forecasting website[i] is the main media through which CWC provides the flood forecasting. CWC has also published on its website, the document giving Standard Operating Procedure (SOP) for flood forecasting in 2018[ii]. The Home page of the CWC’s flood forecasting site says that CWC provides Level forecasting for 166 sites and Inflow forecasting for 60 sites. SOP document, however, gives these figures in Table 1, but in Table 2 (as also the full list given in Annexure 1.1 of SOP document), it gives state wise break up for 182 Level forecasting and 93 Inflow forecasting sites. So we can see anomalies in these two sources even about the number of forecasting sites.

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Dams · DRP News Bulletin

DRP News Bulletin 1 October 2018: Hungry Water Effect due to Dams & Unsustainable Sand Mining Worsened Kerala Floods

Dams and reservoirs make rivers sediment-starved and menacing manifold downstream. While heavy rainfall is also a key factor behind the floods, hungry water had a more pronounced effect, says D. Padmalal, Scientist and Head, Hydrological process group, National Centre for Earth Science Studies.

– “When the sediment transport is interrupted, the potential energy of the hungry water released from dams will scour the river banks downstream, uprooting trees or riparian vegetation and damaging bridges and other engineering structures,” explains Dr. Padmalal. Overloaded with silt and clay from the eroding river banks, the highly turbid and viscous water clogs drainage channels. Subsequent discharge of water from the dam will lead to inundation and waterlogging of large areas.

– Hungry water can also develop in high gradient river channels devoid of adequate quantity of sand and gravel, especially during periods of high rainfall. “Years of uncontrolled sand mining have left most of the rivers in Kerala depleted or exhausted of sand and gravel. This creates a situation similar to the release of hungry water from dams,” notes Dr. Padmalal. When the river channel has adequate supply of sand and gravel, the potential energy of the water is used to transport the mixture. The water does not scour the banks or turn muddy.

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Dams · DRP News Bulletin

DRP News Bulletin 24 September 2018: If NGT Can’t Provide Environment Justice…

Unless immediate corrective action is taken, the NGT which has till recently served as an institution to provide environmental justice, will increasingly become an institution to perpetuate environmental injustice. If this is to happen, it will be a sad day for both India’s environment and democracy; writes Ritwick Dutta.

– Last few months have seen a massive decline in public confidence in the NGT. The first wake-up call was in July when the new chairperson of the NGT commented that around 50% of the petitions before the tribunal were filed by “blackmailers”. Nothing could be more distressing because this comes from an institution that was created to protect the rights of the people. Recently, the decision of the chairperson of NGT to rehear 18 cases, which were reserved for judgment, has raised concerns about both propriety as well as legality.

– The NGT, over the last two months, seems to have evolved four approaches to deal with litigations. First, dispose of existing cases. Second, form committees, comprising mostly people who were responsible for the problem, and outsource even adjudicatory functions. Third, refuse to entertain matters on the ground that the govt has approved the project or other hyper-technical grounds. And finally, rehear cases which were earlier reserved for judgment.

– One is not expecting the NGT to always give judgments in favour of those who approach it for protecting the environment. Rather, the cause for concern is the general reluctance of the tribunal to hear matters on merit, to consider the decision of the govt as virtually sacrosanct and submissions of project proponents as cast in stone. It must not be forgotten that the NGT is not a special tribunal, but a specialised tribunal set up to adjudicate on complex environmental issues through the use of both judicial and technical expertise.

Continue reading “DRP News Bulletin 24 September 2018: If NGT Can’t Provide Environment Justice…”

Dams · Floods

INDIA: Overview of CWC Flood Monitoring Sites

Central Water Commission is the only agency doing flood forecasting in India. As per CWC’s Flood Forecasting website[i] the Data Flow Map has information about 226 Flood Forecast Sites in the country comprising of 166 Level Forecast Sites and 60 Inflow Forecast Sites. It also monitors 700 Flood sites, information made available through List Based Exploration and Hydrograph View, but no flood forecasting is done for these sites.

In order to better understand the CWC’s flood monitoring and forecasting work, SANDRP has published report of CWC’s Level Forecast, Inflow Forecast and level monitoring sites in 5 zones of North India[ii], North East India[iii], East India[iv], South India[v] and West India[vi].  Through this report, we have presented all the data at one place with links to separate zone wise reports with detailed description.

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Dams · Floods

WEST INDIA: Overview of CWC Flood Forecasting Sites

Central Water Commission is the only agency doing flood forecasting in India. As per CWC’s Flood Forecasting website[i] the Data Flow Map has information about 226 Flood Forecast Sites in the country comprising of 166 Level Forecast Sites and 60 Inflow Forecast Sites. It also monitors 700 other sites, information is made available through List Based Exploration and Hydrograph View, but no flood forecasting is done for these sites.

In order to better understand the CWC’s flood monitoring and forecasting work, in this article, we have given an overview of CWC’s flood forecasting and monitoring sites in West India. It includes state wise list of CWC’s Level Forecasting, Inflow Forecasting and level monitoring sites in 5 States in West India. Similar report has been published for North India[ii] and North East India[iii] and East India[iv] and South India[v]. This is the last part in the series.  Continue reading “WEST INDIA: Overview of CWC Flood Forecasting Sites”

Dams · DRP News Bulletin

DRP News Bulletin 10 September 2018: NIDM Lecture on Role of Dams in Kerala Floods

National Institute of Disaster Management, Ministry of Home Affairs, Govt of India invited Himanshu Thakkar, Coordinator of SANDRP,  to speak on the topic at IHC on Saturday. At the packed hall with participants that included members from Central Water Commission, National Disaster Management Authority, Embassies, Media and Civil Society,  the speaker explained how unwise and  unaccountable operation of dams, violating all norms, hugely contributed to the proportions of the Kerala flood disaster. Giving the example of Idukki dam, he showed, how if the dam was operated as per rule curve,  its contribution to the floods could have been reduced by over 50%. Similar is the story of other dams in Kerala.

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Dams · DRP News Bulletin

DRP News Bulletin 3 Sept 2018: CHINA HAS STARTED DECOMMISSIONING DAMS

In a mountain village in southwest China’s Sichuan province, authorities have demolished seven small dam projects this year along a river to clear illegal developments in a new nature reserve. The demolition is part of a nationwide programme to close hundreds of tiny and often ramshackle dams and turbines and bring order to China’s massive hydropower sector after years of unconstrained construction.

The dams sat on an unnamed tributary of the fierce and flood-prone Dadu river, which feeds into the Yangtze, Asia’s largest and longest river, where the government says the “irregular development” of thousands of small hydropower projects has wrecked the ecology. But green groups say the campaign will not necessarily save the environment because it will not affect big state hydropower stations, which they say have caused the most damage.

On the 48 km Zhougong, authorities have already demolished small projects built in nature reserves or encroaching upon new “ecological red lines” drawn up to shield a quarter of China’s territory from development.

The government says small dams have disrupted the habitats and breeding patterns of many rare species of fish, although green groups argue the damage wrought by bigger dams is more severe, with entire towns and ecosystems submerged in water, which they say increases the risk of earthquakes, landslides and even climate change.

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