Saturday, October 15, 2011

WIO Special Note III on Odisha Floods 2011

Special Note III on ‘Odisha Floods 2011’
Water Initiatives Odisha[1]

How Hirakud floods are man-made?

Let me narrate the story of a woodcutter who was cutting the branch of a tree with an axe from morning to evening for several days.  One day, a person passers-by asked the woodcutter to show the axe.  The axe was blunt.  He advised the woodcutter to get the axe sharpened.  The woodcutter said, “I understand this.  But my master says, if I go for sharpening the axe, who will do this work?”  The situation is something like this in the field.  People are busy in work and have no time to learn and give heed to this.  They are working with out-dated knowledge.  For this workshop, the master mind has played a role and hence we are meeting today.

-          This was said by the then Engineer-in-Chief, Water Resources, Govt. of Orissa in September 2005

Dams are monsters.  Even though these have been lifeline for the people of the civilization, from point of view of potential hazard, it is a monster, if not monitored for its proper health and ther is an outburst, the entire Geography and History of area will be changed. 

-          Said by Minister of State, Water Resources, during the above workshop in 2005.

In fact, once dams are built, the safety and security of the people at the lower levels, during floods, becomes heavily dependent on the efficient management of the dam.  As the Minister rightly pointed out, “Sometimes release from the dam makes their life miserable.  Hence, the dam authorities are to operate the gates of the dam efficiently, in such a way that the life and property of the downstream people are safe.”  Has the Hirakud dam been properly managed?  We don’t think so.  The latest spell of floods this September last shows how.  

The September Floods

On 9th September, as 10, 51,123 cusecs of water was entering into the 746 sq km reservoir, Asia’s longest earthen dam looked so small and helpless.  The authorities, who virtually waited the water to come to this unmanageable proportion, were forced to open 59 gates - 49 out of those opened in a span of 48 hours – only to be able to release 9,74,887 cusecs of water.  At such a peak, when the dam’s safety comes to a stake and there is no other way available with the authorities than to release the water which then goes on to devastate millions of people downstream.   We immediately questioned this faulty way of managing the dam’s flood control operations as the reservoir level was continuous kept at a very high level.  Please see the box “Up, up and up” for an analysis of daily flood operations of the dam between 2nd to 10th September.  However, as a regular practice, the authorities denied these charges.  In September 2008, almost the same thing happened and we had raised the issue then too.  The authorities then said they are looking into the matter and that an expert committee will be formed to check such devastations in future.  Three years on, we are doing the same exercise.  The casual and stereotype approach of managing the dam continued, as a result of which a flood that could have been moderated was let loose to devastate about 3.5 million people 19 districts.  At least 41 people were killed and 10 were reported missing when the Govt.’s final update on Mahanadi floods came on 21st September.  In the meanwhile, we hear from the department of water resources that a committee was set up in 2009 and that its suggestions were incorporated during operation of the reservoir during this flood.  However, in reality, we did not find any change in the modus operandi than what we saw in 2008. 

Up, up and up

On 2nd September, when the inflow forecast for 24 hours was 173042 cusecs, 10 gates of the HIrakud dam were open.  This increased to 22 gates by 4th as rainfall was excessive at upstream nearby places Burla at 153.4 MM and Hirakud at 130.4 MM.  The rainfall at Seorinarayan (Chhatisgarh) discharge station in the upstream that day was 13 MM that was to take about 14 hours to reach the reservoir.  Further it was 20 MM at Nandaghat, 48.0 MM at Champa, 28.1 MM at Tarapur, 13.0 MM at Ghorari, 77.6 MM at Saradihi and 27.0 MM at Deogaon; all upstream stations.  So, within one hour (at Burla and Hirakud) to about 30 hours (at the farthest discharge station), all this water was to come to the reservoir.  That day itself the inflow was 380741 cusecs but the outflow was maintained at the same level, leaving the reservoir at a very high level of 624.97 ft. 

The next 24 hours’ inflow forecast was 395525 cusecs but the dam gates were further closed and on 6th September only 12 gates were open.  So, while the inflow was 314880 cusecs, the outflow was drastically low at 233746 cusecs.  On that day, even though the rainfall at nearby upstream stations reduced by almost half, it was not too less.  However the rainfall at most of the far off stations had increased voluminously.  This means the reservoir was to continue receiving higher inflow, which was going to gradually increase.  But the reservoir was kept at a higher level of 624.87 ft. 

Very obviously the next day i.e. on 7th September, the inflow into the reservoir increased to a huge volume of 618340 cusecs, almost double of the previous day.  The authorities then started to realise the blunder and opened 24 gates.  Going by records, each gate takes an hour to open.  So, in 12 hours they could open only 12 gates.  This resulted in a high inflow but low discharge at 418220 cusecs and the reservoir level could not be lowered.  It was at 626.23 ft.  At such water levels safety of the dam comes into stake and the authorities have no option than to release more water.  So, by then even though the rainfall had increased in almost all upstream stations with slight decrease in the nearby ones, and even though the projected inflow on the next 24 hours was almost 635665 cusecs, and the desperate effort to start opening the gates had begun, they could only open 42 gates by which they could discharge only 711542 of the 997428 cusecs that was inflowing.  And the reservoir level had to rise to 627.02 ft.  What is important to note hereis that out of the projected upstream rainfall, the reservoir received almost 30% extra.  This definitely created the extra unprecedented impact but the plight was not going to be much less even if the dam received only the projected inflow.  The damage down streams was already done by then and despite all efforts the authorities could not moderate the flood. 

The next day, i.e. 9th September, when the reservoir received a whopping 1051123 cusecs of inflow – just a little less than the projected volume, the authority was but forced to open 59 gates only to be able to 974887 cusecs of water.  The reservoir level thus rose to 628.50 ft, virtually leaving no further scope for the authorities than to let the flood loose and do as much devastation it wanted to.  This resulted in the increase of the reservoir level to 629.25 on the 10th. 

Govt. records say that the maximum discharge ability of the Hirakud dam is 15 lakh cusecs.  Imagine, if at 10.5 lakh cusecs of discharge the dam wrecked this devastation, what would happen at that level.  The dam itself may not survive then.  This shows how the Hirakud dam is virtually a failure in flood control. 
The point that we want to bring home is, the dam authorities lost the opportunity of moderating the flood by keeping the reservoir at very high starting from 1st August and then kept on increasing it gradually.  This is contrary to what their own documents and reports have been advising them.

Shying away from the hard reality of failure to manage the floods, the authorities first blamed Chhatisgarh rains for the flood; then other factors and finally – while responding to the Governor’s call for establishment of a high level independent committee to inquire into the alleged mismanagement – blamed Chhatisgarh waters again, even as only about 15 per cent (1,77,000 cusecs) of the total inflow on peak flood inflow time came from Chhatisgarh rivers (as informed by the Chief Engineer).  The fact that there is no proper mechanism to monitor flows from rivers from inside the state; and that there is a severe lack of coordination between Odisha and Chhatisgarh in managing the flood flow – that we had raised - were never admitted.  At that time, as was informed by the Chief Engineer of the dam, Ib and Bheden rivers were contributing 1,00,000 cusecs each.  Actually, flood management of the Hirakud dam has always been a controversial issue.  Each time there is a flood the authorities try all ways to cover up the failure of the dam in managing the same. 

This time too, despite clear cut evidence that the dam was kept at a very higher level from the minimum recommended level, they kept saying that they did not violate the designed Rule Curve.  This is what the Secretary of Water Resources has repeated in recent media statements informing that they have reported to the Governor about this.  Buying his argument would mean the management of the dam was perfectly done according to the Rule Curve.  But that also means, the dam has failed miserably.  Would he or his department agree to this?  They won’t admit that managing flood control operations with the help of an old and obsolete Rule Curve itself is faulty and gives rise to mismanagement of the dam increasing the risks of floods and devastations.  The current floods are the worst in recent decades. It would be interesting to see what govt. reports and representatives have said about the dam; its flood control ability and the Rule Curve. 


Strangely, there is no storage earmarked for flood control:

The only existing reservoir scheme for flood control measures across Mahanadi is the Hirakud dam. This is a multipurpose project where irrigation and power generation are other important benefits in addition to flood control benefit. But strangely, there is no storage earmarked for flood control. The FRL and MWL are kept same (630 ft RL). The flood storage is obtained through the operation schedule (rule curve). The operation schedule approved by the Central Water Commission never allows the reservoir to be sufficiently at lower level to absorb the inflow from the U/s catchment of 83,400 sq km, especially if the flood hits late in monsoon. The live storage is rather small for such a large catchment. The safety of the dam is always endangered when the inflow approaches the PMF value. 
(State Water Plan 2004)

The projects which were constructed prior to 1968, the spillway design flood was determined basing on the empirical formulae, envelop curves or frequency analysis.  Let us discuss about Hirakud.  During 1947, the magnitude of maximum flood discharge at head of delta i.e. Naraj was estimate as 15.7 lakh cusec based on long term gauge observation at site.  This flood was reduced in proportion to 3/4th of power of catchment area to obtain a value of 11.5 lakh cusec at dam site.  Later on, International Engineering Co. evaluated the design flood from study of flood in Godavari basin and with their knowledge from other major river basins of the world as 18.3 cusecs.

But in 1952, a 500 year return period flood was calculated as 15 lakh cusec which was adopted as spillway design capacity.  Since the spillway of the same order as the peak inflow design flood (i.e. 15 lakh cusecs) has been provided at FRL, it seems that no routing has been done for this flood.

In 1974, the PMF was estimated as 28.74 lakhs by a team of experts constituted by Govt. of India for formulating rules for flood conservation and flood control below Hirakud. 

In 1982, CWC finally communicated PMF as 14.59 lakh cusec (which is higher by almost 10 lakh cusec).  This necessitated provision of additional spillway to accommodate flood of such high this magnitude. 

As there may be serious problem in providing auxiliary spillway for pasing this flood from techno-economic consideration, it was therefore thought of to regulate the flood by advance release from the reservoir by use of flood forecasting and flood warning system.

Safety of the dam is primary concern and it overrides all other consideration during operation.  The operation should be in such a manner that it balances in best possible way the two conflicting uses i.e. flood conservation for generating additional power and flood control. 

(Er. G. C. Sahoo, Former Engineer-in-Chief)

No lessons learnt

In fact, several other documents of the govt. itself have been pointing out that a lower reservoir level before onset of monsoon is the most effective way to moderate high floods.  However, the reservoir level was kept at a very high level, leaving little scope for the flood waters to pass without creating much damage.  First of all, going by the realisation of its own Water Plan, the water resources department should have lowered the FRL by several feet as an earmarked flood water space.  Instead of doing that it kept on increasing the reservoir level and kept it almost near to full even much before the currently practiced obsolete Rule Curve suggested.  This definitely gives one the impression that this was done with sheer assumption and not through any scientific forecasting methods.  And this fuels to apprehensions by several quarters that the reservoir was deliberately kept at higher level to satisfy the new priorities of the dam i.e. to provide water to burgeoning industries around the reservoir. 

As such also, as evident from all the above discussions, the dam has miserably failed in its primary objective due to its multi-purpose nature.  Further, considering that the dam’s water retention capacity is already reduced by about one third; and its initial design is already a faulty one that cannot properly balance between its multipurpose functionalities, the govt. in first case, should never have allowed industries to draw water from this reservoir.  Without making any review of the fallacies in the design and the functionality of the dam, the govt. kept on adding new priorities. Further, the Rule Curve of 1988 was supposed to be reviewed and changed in 1998 and then in 2008, was kept in force and no serious improvement has been brought in the flood forecasting, telemetry analysis and inter-state coordination aspects of the dam’s management. 

The State Water Plan admits that manual collection of information involves human error and consumes time; data transmission mechanism is unreliable and more so at the time of cyclone and flood; the existing data communication mechanism is time consuming; considering a single UG for a big catchment unit area up to 60,000 sq km involves error; process of estimation of effective rainfall error; and that there is enough scope for development in the existing flood forecasting mechanism. 
Emphasising on the need for proper flood forecasting, researchers of IIT, Roorkee mentioned that “Out of 19 floods 14 are due to intercepted catchment downstream of Hirakud.  As far as structural measures are considered second flood moderation structure is a rare possibility.  The existing flood forecasting system requires a lot of improvement.  The present weariness is the frequency and magnitude of the flood. The present decade has seen so far 4 floods 2001, 2003, 2006, 2008.  The delta of Mahanadi is encroached day by day, due to growth of activities. This delta is highly fertile and thickly populated (400-450 persons /” For more information on what experts have spoken about Hirakud dam and the issues we have raised, please see the box “Experts Speak” at the end of this paper.
Responding to the call of the Governor of Odisha for formation of an independent enquiry committee to probe the alleged mismanagement of Hirakud dam during flood control operations, the Secretary, Water Resources of the state has said that a committee is already formed in 2009 and that the recommendations of the committee were taken into consideration during this year’s flood management.  However, we at Water Initiatives Odisha (WIO) don’t buy this.  We had urged upon the govt. of Odisha to release a white paper on flood operations of the dam in 2008; then in 2009 on the unnatural reduction of power generation and now, this year, we realize that no change has taken place in the way the flood waters were managed by the dam.  So, the flood devastation is clearly man made. 

Time to act

We urge upon the govt. to:
  1. Release a white paper, through constitution of an independent inquiry committee, on the flood management by the dam with day wise details from August 1st to September to 30th providing information on what all factors were considered – with all details there in – to keep the reservoir at a particular level on a particular date.  This should include the flood forecasting upstream and downstream; inflow and outflow at different stations and travelling time of flood waters between stations; flood warnings issued; so on and so forth.
  2. Revise the Rule Curve with immediate effect considering the past experiences of floods, climate change and related factors.
  3. Release a status paper on the life, threats and priorities of the Hirakud Dam.
  4. Upgrade and modernise the flood and weather forecasting as well as warning mechanisms in place.
  5. Start dialoguing with the people of the river basin and devise a Flood Management Policy that talks about river basin management through forest and run-off water conservation; flood plain zoning and management; clearing congestion at the deltaic plains; initiates an interstate mechanism with Chhattisgarh to manage the Mahanadi and its ecology.
  6. Refrain from any further big dam and barrages across the river.  Instead, go for small water harvesting and irrigation structures that will not only control flood in a decentralized manner but also recharge the basin as a whole. 
  7. Review the water allocation to industries from the Hirakud reservoir and upstream rivers and stop giving away any further water to industries from there.

Experts Speak
Almost five decades down the line, the official rhetoric of controlling the Mahanadi has been replaced with a concern for saving the dam itself. In July, hundreds of villages in the Mahanadi Delta were flooded by a surge of water caused when authorities opened 51 of the dam’s 64 gates in July.
Engineers feared that the rapidly rising reservoir could overtop the dam, causing an even greater disaster. In the words of Orissa’s chief secretary, D. P. Bagchi, “the dam’s safety was of prime importance.” The Hirakud Dam is holding back flood waters as designed, but only to release them in lethal torrents.

To explain this irony as a story of excessive rain would wrongly perpetuate the myth that flood control through embankments and reservoirs is a viable and unavoidable response to bank-bursting rivers. The Orissa Delta, much like other deltas in eastern India, has, over the past 150 years, been transformed from a flood-dependent ecology to a flood vulnerable landscape. This has occurred through a range of technological interventions driven chiefly by political considerations.

In Orissa, a prescient flood committee of 1928 noted that floods were inevitable in a deltaic country and it was “useless” to attempt to thwart the “workings of nature” through flood control measures. This committee argued that in Orissa the problem was not how to prevent floods but how to pass them as quickly as possible to the sea and therefore the solution lay in “removing all obstacles” from the path of the flood. The report of the 1928 committee, however, was buried by the politics of the period which instead facilitated the construction of the Hirakud Dam.

More recently, the World Bank studied 25 large dams in India and singled out two that were particularly unable to cope with high flood flows, one of which was Hirakud. The investigators wrote of these two dams that “the consequences of dam failure during a major flood would have to be described with some adjective beyond disastrous.”

-          Excerpts from Politics, not Nature made Orissa floods calamitous Rohan D’Souza, in The Telegraph – July 25, 2001 on the July 2001 Floods

India’s Hirakud Dam was first justified in the name of flood control, yet extreme floods in the Mahanadi Delta between 1960 and 1980 were three times more frequent than before Hirakud was built. In September 1980, hundreds of people were killed after releases from Hirakud breached downstream embankments. Orissa’s Chief Minister admitted that panic releases of water from Hirakud were responsible for much of the devastation but argued that if the water had not been discharged as quickly as possible, the dam could have failed.

-          Patrick McCully, in an undated paper

The wrong operation of Hirakud Dam is majorly responsible for the current flood disaster in Mahanadi basin in Orissa. Ever since Aug 1, 2008, when the rule curve for current year came into operation, the Hirakud dam operators have kept the water level at the Hirakud Dam way above the rule curve recommended for the dam in 1988. Had the dam operated in a way to keep the level below the recommended level, the current flood disaster could have been avoided, it impact hugely reduced.

-          Himanshu Thakkar, in response to the September 2008 floods.
For further details, please contact:

Ranjan K Panda
Water Initiatives Odisha: Fighting water woes, combating climate change... more than two decades now!

R-3/A-4, J. M. Colony, Budharaja
Sambalpur 768 004, Odisha, INDIA
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[1] Water Initiatives Odisha (WIO) is a state level coalition of civil society organisations, farmers, academia, media and other concerned, which has been working on water, environment and climate change issues in the state for more than two decades now.

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