Flooding in Nowshera Valley 

It has been repeatedly stated that the water for KBD will cause severe flooding in Nowshera valley, and has been constantly refuted by WAPDA through various tactics.  

The flooding history of Nowshera describes the flood of 28^th and 29^th August, 1929, as having reached a maximum of 951-ft level above the mean sea level. The hydrologists have worked out the average return period of such a flood as 1 in 100 years.

A relatively lesser intensity of flood was experienced in 1978, which touched the heights of 945-ft above mean sea level. (Ref: Dr. Kennedy Report).

It is feared that, if the water level rises to the 1929 heights, or even the 1978 levels, it would be fairly high above the normal reservoir retention levels, thereby causing major destruction in the towns on the River Kabul banks, and overtopping the Kalabagh Dam itself.

To further aggravate the problem, the increased sedimentation overtime, may raise this height in River Kabul much further, and bring large-scale destruction in the surroundings.  

To technically address the issue, the following monthly average flows of River Indus needs analysis : 

Reference: Dr.Nazir Ahmad, Water Resources of Pakistan and their Utilization

 Form the above table, it becomes evident that more than 65% of the annual water flow of Indus takes place between the months of June to September each year, when the snow melts in Himalayas and Karakoram Range combines with the monsoon season flows. And the remaining 35% flow is spread over the 8 months period from October to May.

Saeed A. Rashid, in his book "KBD; A Scientific Analysis", has analysed the problem. He reveals that "Assuming a normal distribution, 68 percent of the times, high floods could bring an inflow of 27 MAF in July, showing the most possible probability of larger flows coming into the Indus River System. Only 4.6 percent of the times a flood could bring an inflow of 34.02 MAF, and there is 0.01 percent chance of a flood bringing in 46.06 MAF in the month of July.

As per the design parameters, the retention level of Water at KBD is just sufficient to contain the September inflow and the peaks are planned to be passed on, as it is.

Even if there is a capacity to contain a flood of 34 MAF, it will only flood the country upstream, instead of flooding downstream. Whereas the downstream river regime is better adjusted to handle large volumes. And there would be large-scale devastation in upstream habitat areas".

 In the original design, WAPDA had provided for the construction of protective dykes around the major cities of Kabul River, so as to protect the water from over-spilling the banks of the river and destroying life and property. Which, upon the objections from NWFP (Pukhtunkhwa), had been eliminated with the reduction of 10-ft reservoir level, claiming to solve all the flooding problems.

 Intriguingly, the revised designs show the dam height as the same El.940-ft above MSL, leaving a ridiculous 25-ft freeboard over the normal reservoir level, as against 5 to 7 ft common practice.

 This raises the questions:

1. Why was the flooding danger ignored in the first instance ?
2. How will the 10-ft reduction in reservoir level altogether avoid the 25-ft dykes at Nowshera?
3. Why has the dam level been maintained at the same 940-ft elevation, leaving the ridiculous looking 25-ft freeboard over the normal retention level ?
4. Why has the WAPDA been overshadowing the sedimentation effect in Kabul River, feared to raise the bed level and exacerbate the flooding problem.
5. Why has the WAPDA been pleading the utility of Munda Dam in reducing the flooding problem at KBD, when the Munda Dam has only 0.37 MAF of flood storage, and can play only an insignificant role in reducing the extreme seriousness of floods at KBD?
   (Ref : PC-II for Feasibility Study of Munda Dam Project, March 1997, WAPDA)
6. Why has real model analysis of sedimentation behavior been avoided, so as to technically address the issue ?