Engr Iftikhar Ahmad

To fully comprehend the KBD impacts in the long run, its geophysical and geological environment along with the mechanics of water flow through soils needs to be understood in more detail.
In this respect, two important pointers appear in the topographic view of the proposed site of KBD i.e, the salt range and the location of the five oil fields near the proposed dam site.
To be able to visualise the role of the salt range in the KBD's feasibility, it is necessary to magnify and elaborate the section of the ground between the Murree thrust and Salt Range thrust.
The harmless geological formations of Potohar Plateau become more complicated due to the folding of salt strata into the shape of a bowl.
It is believed that about 210 million years ago, the movement of tectonic plates forced the salt formation to fold over into the shape of a bowl, due to which the northern edge of the bowl appeared close to the Kalachita Range, north of KBD reservoir, while the southern rim appeared in the form of the famous Salt Range, south of Kalabagh dam site.
River Indus bifurcates the southern rim so that Kohat Range falls on its west side and the Khewra Range on its east side. 
The layer of salt rock, sitting 2000 metres under the KBD site, is perhaps of no consequence as the vertical permeability of water is not likely to reach that level. However, there are salt deposits and alkali brines at low to medium depth near the rim of the bowl. And these brines tend to be at high pressure and free flowing in nature.
Under the tremendous load of the dam structure and tons of stored water (70 tones per square meter), the salt solutions are likely to rise in vast sheets to mix with the water of the reservoir.
This becomes more important, if the relation of Indus Basin soil's permeability is studied with respect to the geological history of the formations. Which suggests that the lateral permeability of any formation tends to be greater than its vertical permeability, for the possible reason that the soil particles are more consolidated under the vertical pull of the gravity than the laterally acting forces, which are less systematic than the gravitational force.
A relation of vertical and lateral permeability of local soils, in the different canal commands of Pakistan, is presented in the following table, so as to emphasise the importance of this very vital factor in the ultimate operation of the KBD.
>From the above table, it is evident that the lateral permeability of soils gradually decreases, as we move downstream towards the south, and the lateral permeability of DI Khan command is five times that of South Rohri command.
This shows that, in the Indus Basin Model, the lateral permeability is greater in the Kalabagh area and within the area of the pond, and the water is feared to flow in the lateral direction, more swiftly as compared to the vertical direction.
The relatively high permeability values of the soils, in the vicinity of KBD, are important with respect to the possible long-term impacts of the reservoir in terms of increased salinity and enhanced water seepage, to further exacerbate the already experienced system management problems. These will be discussed later; long-term impacts of KBD, in more detail. However, for the moment the geophysical and geological environment of the KBD site cannot be anything but worse for the erection of a storage reservoir of such a huge mass of water, meant for irrigating the downstream lands.
Location of the Dam on a fault line
The proposed KBD site is situated in an area known to have fault lines and fractures. The LANDSAT and SPOT imagery of the proposed KBD site indicates a right lateral fault known as Kalabagh Fault and another known as Kharjawan fault, cutting the KBD site NE-SW between Indus and Kharjawan Nala on the Right Bank.
Geologically, the tectonic plates known as Pak Plate and the Asian Plate (Tibetan Plateau) are both greatly compressed and technically active.
It is a known fact that the compression and collision of moving earth plates cause mountains to rise, and the Himalayan and Karakoram mountains continue to rise by a few millimetres each year due to the same compression. Such a phenomenon is bound to create instability in the area to a substantial degree, thereby making the dam structure prone to seismic damages in future.
Further, it has also been observed that large dams induce earthquakes, because of their large water masses, and plays an important role in intensifying the impacts of small-scale earthquakes.
Thus the construction of Kalabagh dam at the proposed location is to play with the dangerous consequences of earthquakes, and putting the life of downstream inhabitants at stake.
Design drawbacks in KBD project
Apart from the inherent planning drawbacks, the KBD also suffers from a variety of technical shortcomings. These vary from selecting a site, having the poorest capacity inflow ratio to that of proposing engineering designs making it the most unpredictable dam to operate.
Some of these aspects of the KBD are briefly discussed in the following paragraphs.
Site with poor capacity-inflow ratio
The selection of site for a dam and its hydraulic design depends on the capacity-inflow (CI) ratio, and a favourable CI ratio indicates a longer life of the reservoir.
For KBD, the capacity-inflow ratio is 6.1/90=0.07 i.e 7% with respect to the live storage of the reservoir (for both the Indus and Soan limbs). Since Soan River is an Indirect limb of Indus, therefore the actual capacity inflow ratio for the main Indus stem would be 3.5/90=0.04=4% which is very poor, for the design of a storage dam.
Disastrous sedimentation
Sedimentation and silting are a regular feature of irrigation structures, weirs and dams. One of the most important contributions of civil engineering in this field has probably been the use of the energy of flowing water to maintain the balance of the system.
The science has been extensively researched, but is considered to be still in its empirical state. In this respect, Prof. G.G Stokes has contributed a scientific approach and has developed the famous "Stokes Law" to form the basic principle of sedimentation process. It says:
Vs = (3.3gd (Ss-1)0.5
Where "Vs" is the settling Velocity of the Particle, "Ss" is the Specific Gravity of the Particle, "g" is the Gravitational Pull and "d" is the Diameter of the Particle. 
The "Stokes Law" suggests a relation between the Settling Velocity of Particles to their Diameter, while in suspension. And it states that, for a given specific gravity of particles and under a constant gravitational pull, the settling velocity will be directly proportional to the diameter of the particles. Which implies that, the courser particles will have a higher settling velocity than those of the smaller sizes.
The application of "Stokes Law" is found in the design of sedimentation tanks and in the study of sedimentation process in large dams.
As a confirmation of Stokes Law, it has generally been found that the courser particles, in suspension, gets deposited earlier than the finer ones because of a higher settling velocity. This phenomenon has been further confirmed by G.L Assawa in his excellent book Irrigation Engineering (Published by Wiley Eastern Ltd, 1993) as "The courser sediment deposits farther away from the dam, while the finer sediment is deposited closer to the dam".
The applicability of this theory has been further confirmed in the case of Tarbela Dam, where a huge sediment mound has been developed, over the past twenty years, at a certain distance from the dam body.
The application of this law to our KBD case suggests that, the courser particles, in suspension of KBD waters, will have a higher settling velocity than those of the finer ones, and will hence deposit earlier than the finer particles. This suggests that the courser particles will start depositing at the farthest end of the reservoir, followed by next higher size and ultimately the finest in more close proximity to the dam body.
Therefore, within the present design parameters of KBD, it is feared that the sedimentation process will initiate near Nowshera city (the farthest end of the reservoir) and progress downwards, thereby putting the thickly populated towns to high flood risks from the very outset.
In addition, a major impact of the sedimentation process is Aggradation, which causes the bed level, and correspondingly flood levels, to rise to enforceable heights, causing heavy losses. In this respect, G.L Assawa in his book Irrigation Engineering (Wiley Eastern Ltd. Delhi, 1993), states:
"Where the sediment load in a River is in excess of the sediment transporting capacity, the excess sediment gets deposited in the river bed and the sediment load entering a given reach is greater than the sediment load leaving the reach during the same time. This causes a rise in the bed level (and hence the flood level) and decrease the bed slope with time. This phenomenon is known as Aggradation".
The high sediment load carried by River Indus has an important bearing on the design and operating rules of the KBD. This becomes more important, because a number of towns, upstream of Attock, are sensitive to the flood levels, feared to be aggravated with the increased sedimentation overtime.
In the case of Kalabagh dam, the hydraulic drop will be far greater than that of Tarbela, or even Mangla, which will consequently accelerate the sedimentation process.
The siltation process at the reservoir of KBD is feared to be further accelerated due to the diminished velocity from water diversion into the Ghazi Barotha channel, and the reduction in hundred Monsoon days in River Indus to fifty days.
On top of all this, the silt delta in Tarbela reservoir is traveling at a rate of 1/2 mile per year, and is feared to ultimately get deposited in the KBD reservoir, thus reducing the life span of the dam.
Silt clearance problems
The KBD is proposed to have an orifice spillway, 40-ft below the minimum water level of the reservoir. And is believed to work as the ultimate remedy for all the sedimentation problems.
A significant relation of sediment sluicing has been found with the occurrence of piping action under the foundations of the dam.
It has been reported by K.R Sharma in his book Irrigation Engineering (2nd edition, India Printers, Jullundar, 1949) that the Aswan Dam on Nile, constructed on the strongest footings of granite stone, has been found to suffer from foundation damages with each sluicing operation (which discharge the silt at a mean 20 ft/sec velocity). And correspondingly, the sluicing operation consumes a major portion of the operation and maintenance budget of the dam.
Given the 40-ft lower orifice spillway to exclude the sediment of the reservoir, and the geological formations (discussed earlier), it is feared that the recurring sluicing operations would result into piping actions under the dam footing, thereby putting the stability of structure at stake.
Uncertain and inefficient mode of operation
There is no established mode of reservoir operation to sluice the silt, and the recommended mechanism of lower draw down, longer sluicing period, and higher escapages will make the dam act more like a barrage, apart from wasting precious stored water.
In any case, the stored water in the reservoir will have to be emptied each year for the removal of the silt in May, which will be a significant loss of valuable stored water.
And during this process of emptying sluicing and refilling (3 months approx) operation, the power generation would be adversely affected, and would ultimately depend on the normal discharge of the river (after the live storage is exhausted), making the dam generate power on the run-off the river, or thermal systems.
Relation of KBD to Tarbela dam
Originally planned, KBD was to be completed in 1996, and the designers assumed that significant quantities of sand would not be passed downstream of Tarbela Dam, therefore benefiting from its silt retention capability. However, due to the long delay and extensive sedimentation in Tarbela Dam, it is unlikely that any benefit will be derived of the position of Tarbela Dam.
On the other hand, the "Action Plan" suggested by Tarbela Sediment Management Consultants (TAMS), in their latest report of March 1998, to install a sediment sluicing system at Tarbela Dam, so as to recover its lost storage and extend its life by preserving its live storage, leaves little sense in constructing another silt trap to the sluiced sediment of Tarbela Dam.
Backwater effect on Ghazi-Barotha power channel
Part of the River Indus waters have been diverted, at Ghazi (downstream of Tarbela), in the Ghazi Barotha Power channel to generate cheap hydropower at Barotha power station. The 60,000 cusecs water passes through a 52-mile long concrete lined channel on the east of River Indus, and after passing through the power generating turbines, joins the same waters, upstream of proposed KBD site.
Since the KBD is supposed to store, and therefore head-up, the water into its tributaries, it is feared that the net fall at the hydropower station may be reduced in high floods, thereby reducing the power generation capacity.
Although WAPDA claims to have studied the flood water reduction aspect of Ghazi-Barotha project on KBD, and found to be insignificant, yet the backwater effects of KBD reservoir on the Ghazi-Barotha project itself has not been investigated. This becomes more important in the eventualities of highest possible flood levels, since a one-time  backwater inundation of the power station may burn up the whole power station.
Unfeasible right bank canal
The right bank canal proposed was to have 10.5 miles long tunnels of 34.5 ft diameter, 8 mile long tunnels of 40 ft diameter, 4040 ft aqueduct on Kurram River, 12 drainage siphons and 42 drainage culverts, apart from its 80 miles regular length, for irrigating DI Khan, Bannu, Karak, Isa Khel and DG Khan areas. It was lately declared technically and economically unfeasible. 
With this, the last hopes of any possible benefit to NWFP (Pakhtunkhwa) were killed, thus leaving the dam to irrigate and earn royalty (on power generation) to Punjab only.
Short-term impacts of Kalabagh dam project
The KBD is feared to cast its sinister shadows from its very first day of construction. They will vary from the dislocation of a large number of people and the submergence of their lands, houses and settlements, to the ultimate disappearance of long established cultures and ways of life. These are discussed as follows.
Population to be displaced
There had been confusing figures about the number of people to be dislocated by KBD. WAPDA has been claiming a figure of 83000 persons, with 48500 belonging to Punjab and 38500 from NWFP (Pakhtunkhwa). Whereas, independent observers claim a figure of more than 100,000 persons, to be the direct affectees of the dam.
In addition, there will be people indirectly dependent on the water of River Indus, like boatmen, herdsmen etc, who will lose their livelihood because of the KBD.
The investigation of the actual number of affectees is beyond the scope of this research, however, independent researchers have strongly questioned the reality of WAPDA's figures, and consider them invalid.
The WAPDA's figures do not include the thousands of people who would, it is feared, be displaced in the long run, due to the feared water-logging and salinity in Mardan, Charsadda and Nowshera Districts, and the salinisation of sweet water aquifers in Karak and Lakki Districts.
Further, WAPDA's claims of the provincial distribution of dislocated people from the two provinces of Punjab and NWFP (Pakhtunkhwa), becomes more intriguing when one investigates the background of the proposed resettlers. As the majority of people to be dislocated from their homelands in Punjab are Bangi-Khel and Saghari Khattaks and Isa-Khel Niazis, all from Pakhtun tribes, like their brethren, settled in the Peshawar and adjoining valleys.
While it has been pleaded that the dislocated people will be adequately compensated, the fact that the resettlement of these thousands of people will generate acute intractable social, administrative and political problems has totally been overlooked.
It is worth mentioning that a number of Tarbela resettlers at Guddu Barrage command have long sold off their compensation land and are leading a rudderless life, because of their failure to settle down in an alien environment. Whereas many still remain without a shelter or compensation after two decades of the commissioning of Tarbela.
Continued KALABAGH DAM IV