Lessons for California?

The largest pre-industrial metropolis in the world, in today's Cambodia, relied on elaborate waterworks — and died away in the 16th century after "overpopulation and deforestation filled the canals with sediment." Angkor lasted for six centuries and had a peak population of nearly a million, with an urban sprawl similar in scale to Los Angeles. Data from JPL in Pasadena helped make the discovery possible.