Which is the world's longest mainstream dam? 

Which is the simplest and cheapest source of irrigation? 

Which of the following is dug at shallow depths? 

Which one of the following is the backbone of modern development? 

Which of the following is done by capturing and storing water locally in sub surface water reservoirs?

Name the canal which are constructed by putting some form of barrage across the river. 

Which of the following is the joint project of Andhra Pradesh and Karnataka? 

Which of the following is a geographical area that drains to a common point? 

Which is an important method to conserve water resources, increases agricultural development and stop environment degradation? 

Which one of the following is possible in the river valley system?