First of all, government is misleading the masses that Kalabagh dam is an elixir for every problem of the country whereas the facts and research show a different story. According to Wapda reports it would have an output of 2400MW, a falsely and misleading researched report. Dr. Pieter liefnik proved in his report in volume 1 scientifically that Kalabagh dam can only generate 350MW.
Secondly, due to back water flow a large swarthes of fertile land of central KPK will submerge, approx 190000 acres. It will also decimate the infrastruture of those areas resulting in displacement of more than 100000 people, inundating everything that will comes in its way. It will severly affect kpk in terms of economy and lifes. One thing must be kept in mind that kpk are already dependent on punjab for vegatables fruits and grain.
Thirdly, other rivers which are draining into Kabul river like Swat river , Chitral river, etc will be also affected along with population living beside them due to flash floodings in monsoon. This fact will be well illustrated from the floods of 2005 and 2010 which submerge almost 30% of kpk , even without kalabagh dam. Just imagine its devastation with kalabagh dam, it will inundate nowshera, mardan, swabi and other cities in its vacinity. Even if it doesn't happen, waterlogging and salinity is bond to occur, chaning thousands of acres of fertile land to morose.
In contrast, government has other feasilable options to avail, i reckon that they would not opt that. They can construct katzara dam which has a storage capacity of more than 30 maf and can produce upto 15000Mw.
There are also a number of other scientific facts and figures that suggest the impractibility of this project but it is not a best platform to discuss those subtlities.