Water, or the lack of it, has emerged as one of the greatest sources of stress for California, its people and its native species. Fish populations are declining in the Sacramento-San Joaquin Delta, while farmers are facing short supplies. Urban dwellers have come under pressure to use less water, and underground reserves are being rapidly depleted. Making matters much worse is the ongoing drought, which shows no sign of ending. In fact, forecasts for less annual rainfall in years to come have cast uncertainty on the very future of California and its rapidly growing human population.