By Paul Polak The 13,324 miles of canal system in Pakistan’s Sindh province irrigates 12 million acres of land. That’s a canal that’s long enough to cross the United States three times! This canal system and others like it make as significant a contribution to feeding the world’s growing population as the introduction of the green revolution’s miracle seeds. But big canals come with big problems. Namely, rampant corruption, water wastage, numbingly inefficient operation and maintenance as well as millions of acres of productive land ruined through water logging and salinization. Because of water losses from evaporation, leakage, evaporation, poor operation and maintenance and prehistoric…