To dam or not to dam? Pakistan experts ponder flood strategy

Energy-starved Pakistan relies on a multitude of dams and barrages to prevent Himalayan rivers from flooding and help meet its power needs, but their failure to prevent disaster four years running is making some experts question their utility.
Every year since 2010, which saw the worst floods in Pakistan's history, the country has experienced catastrophic inundations that kill hundreds and wipe out millions of acres of prime farmland, harming the heavily agrarian economy.
Starting when the country was still a part of British-ruled India, engineers embarked upon ambitious projects to harness the water that flows from Kashmir through the length of the country to the Arabian Sea.

Today Pakistan is home to the biggest earth-filled dam in the world at Tarbela, just north of Islamabad, and more than 150 others classed as "large".