Special Note III on ‘Odisha Floods 2011’
From
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 /sq.km.)” 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:
- 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.
- Revise the Rule Curve with immediate effect considering the past
experiences of floods, climate change and related factors.
- Release a status paper on the life, threats and priorities of the
Hirakud Dam.
- Upgrade and modernise the flood and weather forecasting as well as
warning mechanisms in place.
- 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.
- 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.
- 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
Convenor
Water Initiatives Odisha: Fighting
water woes, combating climate change... more
than two decades now!
R-3/A-4, J. M. Colony, Budharaja
Skype: ranjan.climatecrusader
