For an unassuming little fish, the delta smelt (Hypomesus trans­pacificus) has received outsize attention. In the sprawling waterways of the Sacramento–San Joaquin river delta, which channel precious water throughout northern California, the smelt has served as an environmental sentry. When its numbers plummet, water managers flood the delta with fresh water, to the outrage of farmers who would rather have it nourishing their crops.

Yet the drought may finally do for the smelt. As California looks to enter its fifth year of drought, officials face difficult choices on how to manage water over the long term. So far, thanks to resilience built into the water system in past years, Californians are weathering the shortage remarkably well. Cities have opted to control their love of lush lawns, and farmers have shifted to efficient irrigation and other water-saving measures.

But how long can the Golden State’s lustre last? Two new reports (see and highlight possible futures should the drought continue. And the outlook is not always that promising. Water managers cannot simply hope for a rainy winter, perhaps prompted by El Niño. Farmers will still pump groundwater for California’s US$46-billion agricultural industry, so water tables will continue to drop. More at risk are California’s iconic ecosystems, from towering redwood trees to rivers teeming with salmon and trout. Wildlife managers have arranged to keep the most crucial wetlands damp for bird visits, and forestry managers extinguish wildfires as soon as they start. But such piecemeal approaches must be turned into a long-term strategy, much as farmers and urban planners have already done for their thirsty constituents.

Otherwise, the delta smelt may vanish for good.