CHALLENGES TO WATER REUSE

A FADING, decades-old photo illustrates California’s ongoing water woes. It shows a man standing next to a telephone pole in the San Joaquin Valley, the agricultural backbone of the state. He’s marked the pole with signs at different heights, each sign indicating where ground level sat in a particular year. The one at the very bottom reads “1977,” and one about 30 feet up the pole reads “1925.” What made the ground drop almost 30 feet in five decades? The culprit is groundwater overdraft, when communities pump more water from a groundwater basin than rainfall and other sources can replenish. Farming communities in the San Joaquin Valley pumped so much groundwater that the region’s aquifers began to compress and the soil above them collapsed, lowering the ground level. Although the valley has reined in its groundwater pumping, overdraft is still a problem across the state. The California Department of Water Resources estimates this yearly ...