Factoring in the ninety-seven- per-

Factoring in the ninety-seven- per-cent average cost overrun for large dams, a new structure downstream from the Mosul Dam could cost around four billion dollars. Dams are also a foolhardy investment: in our changing climate, desert reservoirs are drying up. More than twenty per cent of the Tigris River’s precious freshwater is evaporating from its reservoirs, leaving behind saline-irrigation water that’s slowly poisoning the adjacent land.