FURNAS COUNTY, Neb. (AP) — Authorities in Nebraska are trying to determine who released 16 million gallons of water by opening a dam on an irrigation channel one night this month — and why. The head of the irrigation district that runs the nearly 48-mile-long Cambridge Canal discovered the problem on Aug. 14 when a gauge on his computer showed the flow of water in the canal had dropped by half overnight. He scrambled to notify farmers and replenish the canal from a reservoir upstream before calling the sheriff. He estimates the missing water was worth about $2,600. Furnas County Sheriff Doug Brown says he’s trying to figure out why someone would release the water and what to charge them with if he finds them.