Should Pakistan build a dam

This is the biggest problem in Pakistan we dont have enough water and Pakistan Prime minister  Imran khan is also urge Pakistan people to donate money to build a dam but the Question is should Pakistan build a dam ? I think no first they are very expensive second you can not stop the flow of river like India did this and face huge floods i am not a expert about this thing but they say the water from the rivers pushes the water from the sea i am not certain about that but it is expensive Pakistan should use other modern method to fulfill its water need which are less expensive like the one use by china and Europe they can grow crops in desert using these technique we can save more water at a less expensive preice