Priority of Katzarah dam
By Engr Fateh Ullah Khan
TECHNICAL scrutiny of the dams planned under the ‘2016 Water Vision’ shows that the majority of them will be ineffective. For instance, feasibility reports for the Kalabagh dam find that its construction would not only be faulty but also highly risky and destructive for Peshawar valley. Owing to the site’s weak foundations, consultants have reported that a hydraulic structure more than 160 feet high cannot be raised at the dam site. Still, Wapda wants a height of 260 feet to store more water.
Located along several fault-lines, the Kalabagh dam requires redesigning on the basis of a maximum credible earthquake reading of 9.5 on the Richter scale — especially in view of the impact of the Oct 8 quake in 2005. The present structural, geological and seismic design for Kalabagh dam is obsolete. The hydraulic design as dictated by Wapda consultants for restricted mid-level sluicing is also impractical as it will not evacuate silt from the reservoir. The hydraulic design is against the recommendation of the consultants, and if adopted would see the sediment load being deposited in the sensitive upstream area of the Attock gorge, causing backwater flow, flooding of the Kabul river and inundating a vast area of Peshawar valley.
Punjab wants the Kalabagh dam for diverting 15,000 cusecs of water through the 170-mile long Left Bank Canal to the Jhelum and Chenab river basins to feed the Mangla irrigation system. Besides creating mistrust, this unilateral diversion of water would be illegal. Moreover, the dam would not produce 3,600MW of power as dependable power generation would be 1,463MW.
Where the Akhori dam is concerned, a panel of World Bank experts under Dr Pieter Lieftinck rejected its proposed height of 250 feet owing to weak foundations. And yet, Wapda plans to raise the height even further — from 250 feet to 420 feet in order to increase its water-carrying capacity. Also, to feed the Akhori reservoir, the height of the Tarbela dam would have to be raised by 15 feet. This would need a separate feasibility study. The earthwork involved for a 250-feet high Akhori dam would be twice that of Tarbela. The 420-feet high Akhori would involve more than three times the earthwork of Tarbela. A canal with a discharge capacity of 80,000 cusecs would have to be constructed to feed the Akhori reservoir for about two months of the year. For the remaining months this huge canal would remain dry. It would stretch across roads, railway lines, motorways etc. The cost of the dam would be about $18 billion.
On the withdrawal of 80,000 cusecs of Indus water for Akhori and 56,500 cusecs for the Ghazi Barotha power channel, the Indus would remain dry for about half the year. The NWFP would suffer seriously due to the diversion of the Indus flow.
We come to the Kurram Tangi dam. Wapda’s calculations of the gross storage capacity of Kurram Tangi dam is 0.614maf. Wapda has ignored the hydraulic data of more than 60 years collected by the irrigation department. The average annual flow observed by the irrigation department is 0.81maf. The maximum flood flow recorded is 203,400 cusecs. The high flood flows and the wet years flood flows besides heavy sediment flows that essentially require a large storage capacity are ignored. Besides this, the erodibility per square mile, the annual sediment load and the total catchment area worked out by Wapda consultants appear doubtful and need fresh investigations.
Kurram river carries a heavy sediment load that can silt up the dead storage of 0.3maf within 20 years. After that, the average annual storage of 0.614maf would be affected, resulting in conflict over water between the farmers of old civil canals and those of the new canals. The water rights of the farmers of the civil canal area would be arbitrarily reduced by less than half. For storing the average annual flow of 0.614maf and creating a dead storage capacity of 0.3maf, the height of the Kurram Tangi dam comes to 290 feet. It is the practice worldwide to ensure that the gross storage capacity of reservoirs is equal to three to five times the average annual flow. The gross storage capacity of Kurram Tangi should not be less than 2.0maf giving the dam a height of 400 feet.
Wapda seems to have inconsistent dam design policies. In the case of Akhori and Kalabagh, both located on weak foundations, the height of the dams has been increased whereas in the case of Kurram Tangi, which would rest on strong foundations, the height has been restricted to 290 feet. It may be noted that Kurram Tangi will benefit the local people and as such cannot contribute to the Vision 2016 storage requirements.
There is consensus on the building of Bhasha dam — a very good dam on the Indus that would have a storage capacity of 7.5maf and generate power up to 4500MW. All provinces have agreed to its construction although there has been a delay of 25 years.
Wapda has concluded that the Munda dam on the Swat river will control the flooding of the Kabul river. This is not correct as Munda would be basically a power dam with a gross storage capacity of 1.29maf and a height of 700 feet. The live storage level of the dam would be 0.67maf and the dead storage 0.62maf. The latter would silt up within a few years. Even at 700 feet, the Munda dam would not have adequate storage capacity to control the floods as it would be a power dam generating 640MW of power.
Like Kurram Tangi, it would benefit the local area and would not contribute to the Vision 2016 storage requirements. Unfortunately, Wapda has missed a dam site at Guroh Dop with a storage capacity of 8.5maf just a few miles upstream from Munda on the Panjkora river, a major tributary of the Swat river.
This brings us to the question of including the Katzarah dam in the government’s water vision. As we have seen, out of five dams four are contributing little towards building storage capacity. In this context, it is only Bhasha that is useful.
The Indus Water Accord allocates 117.35maf of water to be shared between the provinces whereas today about 100maf of water, plus or minus, is available. In order to make up the storage deficiency new dams are immediately needed. Within the next 10 years, this deficiency will be aggravated. About six maf of storage is required to replace that lost to silting at Tarbela and Mangla by the year 2010. The immediate storage water requirement is for 22maf, which would mean the construction of five mega dams on the Indus including Bhasha. New dams, wherever feasible, should never be opposed as they have many benefits other than the development of irrigated agriculture.
Pakistan is fortunate to have a unique dam site at Katzarah that has 35maf storage capacity equal to six times the storage of Bhasha. The NWFP government recommends the inclusion of this dam in the Vision 2016 programme to replace two unfeasible dams at Kalabagh and Akhori that have a combined storage of only 9.3maf. In 2003, Wapda promised that a feasibility report for the dam would be ready by September 2005 but nothing has been done about this as Wapda continues to advocate the construction of the Kalabagh dam.
The site of the Katzarah dam is located in an extremely narrow gorge on the Indus river near a bridge about 20km downstream of Skardu town. The average annual flow at the site is between 27maf to 30maf. The power generation potential of Katzarah is about 15,000MW. Its lifespan is more than 1,000 years as it is snow-fed, almost free of silt and outside the monsoon range. Katzarah would irrigate about eight million acres of land in the four provinces and store 35maf of flood flows that are wasted each year. Even if 25maf of floodwater were stored at Katzarah, Punjab would get 37 per cent, coming to 9.25maf that is 1.5 times the storage capacity of the Kalabagh dam.
Katzarah would function as a super flood-control dam as global warming increases. It would function as a power, irrigation, river regulation, carry-over, replacement, development, water management and watershed management dam. It would stop soil erosion in Skardu valley, which has the most erodible soil in the world and is the source of silt in the Indus river that has caused the rapid silting of the Tarbela reservoir.
The construction of Katzarah dam would increase the lifespan of Bhasha from 80 to 1,000 years and that of Tarbela by about 50 years. No province has raised any technical objection to the construction of the Bhasha and Katzarah dams although there are concerns that the site of the latter is remote. The highly erodible part of Skardu valley soil that is the source of silt in the Indus water would be submerged by the Katzarah dam enabling the latter to act as a unique watershed management dam by preventing the silt from flowing to downstream reservoirs thus increasing their lifespans. Dams are not without routine problems. The basic requirement is that dam should be technically sound and have a long lifespan and excellent service value.
The writer is former chairman Irsa.


