Dam Induced Flood Disaster

Is THDC preparing to repeat the disaster Tehri created in Sept 2010?

Why is Tehri filled up with half the monsoon still to come?

The Tehri dam reservoir on Bhagirathi river in Uttarkashi district in Uttarakhand is filled upto 818.4 m as on August 5, 2013, as per the latest available information on Northern Region Load dispatch Centre (http://nrldc.org/). With permitted full reservoir level of 820 m[1], the FRL is just 1.6 m above current level. At current rate, the water level in the Tehri dam may reach FRL in less than a week. The question is why is Tehri dam being filled up when almost half the monsoon is still to come? And when going by the trend so far, the monsoon is likely to continue to bring surplus rains? Now the Tehri dam is posing a huge, grave and real risk for the downstream areas in Uttarakhand and UP as the monsoon rains continue in all its fury.

In last 35 days since July 1 (level 780.05 m), the water level in the dam has gone up by 38.35 m. In last four days since Aug 1, the level has gone up by 7.85 m. On every single day since July 1, Tehri has been releasing less water than it has been receiving, which means the dam is hoarding water (a detailed list of reservoir level, inflow and usage at Tehri dam from July 1 to August 6 is given in the annexure below). On at least 22 days since July 1, the dam has used less than the optimum quantity of water it can use, that is 572 cubic meters/ sec. The Tehri dam generated 657.65 million units of power during July 2013, which is below the optimum it can generate (744 MU) and also less than what it generated for example in Aug 2011 and Sept 2010. As a direct consequence, while less power was generated, more water was accumulated behind the dam and now the dam is posing a risk to the downstream areas.

Safety issues at Koteshwar Dam: Vigilance enquiry on It may be recalled that in September 2010 similar mismanagement at the Tehri dam led to huge and avoidable floods (for details see page 20 of Aug Sept 2010 issue of Dams, Rivers & People: https://sandrp.in/drp/DRP_Aug_Sept_2010.pdf) in the downstream Uttarakhand and UP. Thus the highest ever flood level of 296.3 m at Haridwar was reached on Sept 19, 2010 (see http://www.india-water.com/ffs/static_info.asp?Id=24). In fact in Sept 2010, the downstream Koteshwar dam of THDC also suffered severe damages due to this mismanagement and now it is unable to take larger flows from upstream Tehri dam. The weak civil works of Koteshwar dam is also now facing vigilance enquiry as per the Aug 4, 2013 report from http://www.energylineindia.com/. The report said, “Vigilance department had expressed its concerns regarding the civil works and works relating to diversion plug, which are extremely susceptible to rains and are vulnerable to lead to major impact on the dam safety… The stalemate at THDC’s 400 MW Koteshwar Dam and Power House (KDPH) has seen work come to a halt in the event of non completion of emergency works for the project.”

97.5 m high Koteshwar Dam 20 km downstream of Tehri dam (photo: hydroworld.com)
97.5 m high Koteshwar Dam is located 20 km downstream of Tehri dam
(photo: hydroworld.com)


AIPEF misleading Power Ministry? It is reported[2] that All India Power Engineers Federation has written to the Union Power Ministry, expressing concern that spillage from Tehri dam will pose risk of flooding of the downstream Koteshwar project. This concern also seems to suggest that Koteshwar dam is not strong enough to take the higher water releases from Tehri that may be required. The Matu Jansangthan[3] has also raised concern about safety of the Koteshwar dam and its impacts. The request in the letter that THDC be allowed to increase the water storage to 830 m is anyway misleading since it is not in the hands of Power Ministry.

Uttarakhand waiting for new disaster? It seems from this situation that unless urgent steps are taken, Uttarakhand may be in for a new disaster pretty soon. It is strange that while this situation was developing over the last month a number of agencies that should have taken advance notice and action have been sitting quietly.

Þ    Central Water CommissionIndia’s highest technical body on water resources is supposed to provide rule curve for safe operation of all dams. It seems CWC has not issued any such safe rule curve for Tehri or the rule curve issued by it is unsafe like it is in many other dams.

Þ    Uttarakhand and Uttar Pradesh government In case of the flood disaster that will happen in the downstream area because of the wrong operation of the Tehri dam, it is the people, lands, property and environment of the Uttarakhand and Uttar Pradesh governments that will be affected. But Uttarakhand or the Uttar Pradesh seems to have taken no action. Uttar Pradesh government is also partner with THDC in the project.

Þ    National Disaster Management Authority NDMA should be concerned about this impending manmade disaster and should have taken action, but seems to have done nothing.

Þ    Union Ministry of Water Resources The Ministry is supposed to be concerned about the safety of all dams in India, but has clearly failed to do anything about Tehri or Koteshwar.

THDC, Uttarakhand Chief Minister, Central Water Commission among others have been making a lot of false claims about Tehri dam having saved Uttarakhand during the Uttarakhand flood disaster during June 15-17, 2013. Our analysis[4] showed that this is clearly false claim and also warned that Tehri could turn out to be a source of disaster in the remaining part of current monsoon. That situation now has clearly developed and requires urgent intervention. We hope all concerned authorities will urgently intervene and ensure that no such disaster happens.

Himanshu Thakkar (ht.sandrp@gmail.com)

South Asia Network on Dams, Rivers & People (https://sandrp.in/)

[1] In ongoing Supreme Court case, THDC does not have permission to take water level behind the dam above 820 m due to lack of progress in rehabilitation. On Aug 27, 2010, THDC was given a one time temporary permission to take water level to 830 m only as an “emergency measure”. Now THDC is seeking SC permission to take the water level to 835 m from the current permissible 820 m, but that is unlikely to be agreed by the Uttarakhand government considering the state of rehabilitation. The case is likely to come up before the Supreme Court in Sept 2013, as per Matu Jansangthan, which is fighting the case.

[4] https://sandrp.wordpress.com/2013/06/28/uttarakhand-floods-truth-about-thdc-and-central-water-commissions-claims-about-tehri/


Reservoir level, inflow and usage (outflow) at Tehri dam during July 1, 2013 to Aug 6, 2013 

Date Reservoir Level (meter) Inflow (cumecs) Usage (cumecs)
01-07-2013 780.05 603.78 462
02-07-2013 780.05 603.78 462
03-07-2013 781.1 554.73 540
04-07-2013 781.1 599.4 538
05-07-2013 781.6 545.81 536
06-07-2013 781.9 680.47 537
07-07-2013 781.9 680.47 537
08-07-2013 781.9 680.47 537
09-07-2013 781.9 680.47 537
10-07-2013 786.6 760.77 540
11-07-2013 787.1 785.2 645
12-07-2013 787.45 633.13 546
13-07-2013 788.45 804.66 546
14-07-2013 NA 749 549
15-07-2013 790.1 798.15 551
16-07-2013 790.1 798.15 551
17-07-2013 790.1 798.15 551
18-07-2013 793.8 910.51 546
19-07-2013 793.8 910.51 546
20-07-2013 796.35 855 475
21-07-2013 799.3 855 236
22-07-2013 800 810.53 459
23-07-2013 802.3 917 541
24-07-2013 802.3 917 541
25-07-2013 804.15 946.5 574
26-07-2013 808.5 1471.92 572
27-07-2013 809.7 972.44 564
28-07-2013 810.50 792.25 569
29-07-2013 810.50 792.25 569
30-07-2013 810.50 792.25 569
31-07-2013 810.50 792.25 569
01-08-2013 810.50 792.25 569
02-08-2013 810.55 730.41 572
03-08-2013 814.70 629.43 573
04-08-2013 816.15 617.8 572
05-08-2013 817.15 NA NA
06-08-2013 818.4 NA 566

Effective Full Reservoir Level of THDC – 820 meter, NA – Not Available. The dates mentioned here are reporting dates, the levels and flow figures are for the previous day.  Source: http://nrldc.org/