Pakistan faces grave challenges and tough decision making in its water management policies. This relates to affirmative measures in flood control and water harvesting, conservation and recharging of aquifers, and human consumption related to agriculture, power generation and potable water. In the best interests of the country, these challenges cannot be relegated any further. Both technical expertise and political willpower are needed to convert this curse into a blessing. While it is the responsibility of technical experts to reach best solutions, the politicians have to shed the yoke of narrow politics and work for a bigger cause.
In view of climate changes, the old template confined to Indus Basin has to be revised to cater for floods rushing out from Northern Pakistan that make Khyber Pakhtunkhwa (KPK) and Northern Pakistan vulnerable to flash floods. This climate change also affects the flows of Rivers Jhelum and Chenab that flow into Pakistan from Indian held Kashmir and excess water discharged by India into Ravi, Sutlej and Beas Rivers besides opening flood gates to inundate areas from Sulaimanki to Fort Abbas. This has become a major source of water for River Indus downstream of Tarbela as also inundating vast tracts that cannot be cultivated. In addition western distributaries emanating from FATA and Suleiman Range also debouch into Indus implying that water can he held back at Tarbela till it reaches its top level and opens possibilities of additional storage in Punjab whilst these tributaries can effectively be dammed to hold maximum quantities of water. Increased storage capacities with dams, lakes and channelized waterways will have the added advantage of recharging groundwater aquifers.
The floods of 2010 or the ones that followed till 2015, were not the worst in Pakistan’s history. That year, over 77 MAF of water equivalents to 8 Tarbela lakes passed though the choke point of Panjnad. In the past, upstream surges at Jehlum, Chenab and Kabul have been three times higher. In 2010, more than 17 MAF (2 Tarbela Lakes) never reached the sea inundating wide expanses in Punjab, Sindh and Balochistan. This contributed to water logging and soil degradation. Total water loss in 2010 was over 80MAF equivalent to 10 years of winter storage. Peak floods in this basin in the past have been even higher. Chenab and Mangla in 1992 recorded much higher floods than 2010. The total wastage of water from Kotri since 1974 has been over 535 MAF or an equivalent of over 1 Trillion US$. This means that the worst of worse could come to pass once against which we have an old and worn out system of regulation and flood protection bunds. Out of box thinking is critical to breakout of the traditional paradigm.
Unfortunately, Pakistan does not have sufficient space to exercise control of the raging Rivers Chenab and for that matter Rivers Sutlej and Ravi that remain in complete control of India. However, it is still possible to store limited water at Chiniot and divert the remaining to other river systems through the existing link canals. It is also possible to divert flows of River Jhelum to Rohtas Dam and subsequently disperse it to link canals. But to ensure that these two rivers remain the main feeders for Indus downstream of Kalabagh, the excess water of Tarbela Lake rather than be allowed to aggravate an already existing flood spike, will need to be stored in the Tarbela lake itself or alternatively channelized to the Soan Basin (Soan Dam) for subsequent release to Indus and thereon. The water management and regulation system will bank heavily on controlling waters of four river systems i.e. Indus, Jhelum, Chenab and Kabul in a synchronized manner. If accomplished over 83% of water worth 8 Tarbela lakes will neither be lost out to Sea, nor a water equivalent of 2 Tarbela Lakes become a cause of inundations and soil erosion. This water will be used to reclaim land in Southern KPK, South Punjab, Sindh and Balochistan giving a boost to agriculture. Vast tracts of arid areas dependent on seasonal rains will become canal fed.
This entire water scheme can be divided into geographical sectors.
Rivers Swat, Panjkora and Chitral will need construction of weirs, run of river power station and alternate channels for power generation and flood control before they debouch in Kabul or Munda Dam in Mohmand Agency. Perhaps all bridges with wider spans and abetments will have to be reconstructed. Munda will act both as a water storage facility and power generation project before the excess water pours into Kabul. Further, like Aswan Dam in Egypt, Warsak Dam will need to be redesigned. The heavily silted river-bed can be sealed with a Grout curtain to build a huge storage of 10 MAF (more than Tarbela) on top. The high Warsak dam will provide flood protection and cheap, four times more hydel power, while requisite quantities of water can be diverted for agriculture. The runoff (equivalent to Rover Jhelum) and flow from Munda will feed Indus at Khairabad, enough to fill the Kalabagh Gorge. The water at Tarbela Lake can be held back depending on flood and rain conditions.
Tarbela Dam will have two exits. First a link canal from Tarbela leading directly to Soan without affecting Kalabagh. The second is the traditional channel that fills Kalabagh. In peak floods, Kalabagh (6.1 MAF) would need just 14 days to fill. In reality, existing flood peak pass at Kalabaghh is more than 25 MAF needing only 7 days. This leaves over 19 MAF that is wasted in floods. Therefore while River Kabul is filling and flooding Kalabagh, excess water from Tarbela can be used to fill Soan. This coordination can take care of worst spikes of flood flow, thus harvesting maximum water and providing maximum flood protection. Soan can continue to fill as long as needed and can be discharged after producing electricity at exit and entries to Indus and Jhelum. This means a realizable power potential of over 15,000MW of electricity.
At Head Rasool and Kalabagh this sector will link with the Jhelum- Chenab sector to form the next sector of water management.
To be continued….