More than half of the rain in Los Angeles ends up in the ocean. With planning and thought, that water could be put to good use by recharging aquifers. This entails studying where the rain falls, permeability of the soil, and avoiding storing water where there is groundwater contamination.
Our model suggests that around 92,000 acre-feet of stormwater runoff could be harvested in the San Fernando Valley, enough to sustain almost 100,000 households at current usage rates. That number has a certain poignancy in the larger context of California’s contested water systems: it is nearly identical to the amount of water that the Los Angeles Department of Water and Power is currently required to use to keep harmful dust from blowing off of Owens Lake, desiccated in part by LA’s thirst.