On Drought and Salt

Tonight, thankfully, it’s raining. About time. L.A. supposedly saw off a brutal drought a year ago. Then came last year’s epic rains, prompting California’s Water Resources Board to officially end the drought last Spring.

Too soon: since January’s deluge, the one which brought mudslides across the Thomas Fire’s denuded 440-square-mile burn scar, it’s been sunny most every day. At one point, temps near the coast rose into the high 80s, remaining in the balmy seventies well after dusk. In the Bay Area, it’s been the warmest winter since records began. The L.A. Times laments that tonight’s storm, limping across California for the next few hours, gives Californians “little to look forward to.”

There are three stock photos that nearly always illustrate any story about drought: 1) a dry lakebed’s cracked clay; 2) a boat marooned in an alkaline desert (the nearly extinct Aral Sea, for instance); 3) a pier suspended above drifting sand. Respecting this tradition, I begin this essay with a photo taken last week. It’s a corner of our back yard unreachable from our parsimonious irrigation system. The cracked clay soil is my way of signaling that I’ll be talking about water shortages.

It is easy to forget that drought is now global. Cape Town residents, even after a recent storm, are still just days away from completely running out of potable water. From Cape Town to California, the nightmare world that climate science has predicted for the past twenty years is coming to pass. The new normal will see  longer periods of punishing drought, interrupted by rainfall which falls too fast and too heavily.

Cape Town and California aren’t alone. BBC recently  listed eleven cities most likely to run out of water in the coming years. Some of these cities, whose populations long ago outstripped local water supplies, are no surprise: Beijing and Mexico City, for instance. Others are something of a shock, for instance Tokyo, London, and Moscow. All depend on increasingly undependable surface runoff for populations in excess of ten million each (and, in Tokyo’s case, more than thirty million). Oddly, BBC didn’t mention Australia, though that country has faced severe water crises over the past decade.

The international consequences are already severe. U.S. military planners and their peers in around the world increasingly fret about the relationship between drought and political instability. (On this point, see Joshua Busby’s report for the Council on Foreign Relations, available for download here). Savvy investors are looking with increasing interest at technologies which can potentially yield greater efficiencies or promise, for instance, to make better use of post-treatment “gray water.”

Every time I think about this issue, I have wondered why the state doesn’t simply invest in desalination plants. So do participants in L.A. Times and San Francisco Chronicle comment boards, many of whom will (inevitably) aim their bile at state officials who could “easily” build a dozen desalination plants and “solve the problem.”

Well, why not? Both Israelis and Saudis have invested massively in desalination, a timely decision given that summer temps now regularly top 125° (no, it hasn’t always been this hot, even in the Middle East).

For one thing, desal plants can wreak environmental havoc by pumping excess salt back into coastal regions, disrupting or destroying littoral ecosystems. Still, when you’re really thirsty, you’re not going to care much about local sea life. You’ll probably think more about a harder problem: cost.

In 2015, one of the world’s largest desal plants opened in Carlsbad, California. The plant can meet 7% of the needs of San Diego  County’s three million people, providing a welcome cushion when supplies from other sources run low. Construction costs, however, topped a billion dollars. Again, this $1 billion will supply just one out of every fourteen gallons used in San Diego County’s farms, businesses, and homes.

Thanks to Prop 1 (2014), the state has already begun funding a few projects statewide, A tranch of $34 million from Prop 1 grants is seeding desal projects for a handful of smaller cities like Camarillo, Laguna Beach, and Antioch. Many of these projects, by the way, will draw water from brackish aquifers rather than from the ocean itself.

This is, as it were, a drop in the bucket. Scaling up from Carlsbad or Camarillo would require another 12-15 world-class desalination plants – and this would supply just a tenth of California’s water needs. Prop 1 provided about three-quarters of a billion for desal development projects. The total cost for a full desalination program would likely start, say, $15 billion. Such a sum is not out of reach. Since the early 20^th century, California voters have willingly taxed themselves to finance the state’s highways, prisons, and educational institutions, not to mention the state’s heroically massive water projects.

Even so, $15 billion is a considerable sum. The state’s controversial high speed rail program, now caught in a morass of mismanagement and cost overruns will, if it’s ever completed, cost more than $10 billion. Nor are these projects which could be completed quickly. Each proposed site presents its own unique and sometimes difficult challenges. Just acquiring the coastal property necessary for such a string of plants will be time-consuming and expensive.

Once such plants are built, Californians would have to confront desalination’s considerable production costs. Desal requires far more energy than most other methods of delivering water. A statewide system meeting just 10% of the state’s needs will likely add around $1000 to an average family’s annual water bill.

It is entirely possible that new technologies will ride to the rescue. In just the last week, U.S. and Australian researchers announced development of a membrane which, if it lives up to its promise, will allow far more cost-effective desalination. There are no guarantees that this or any other innovation will turn out to be affordable, scalable, or immediately available. For the moment, it is best to assume that we’re stuck with what we’ve got.

This leaves one solution: permanent state-enforced conservation, aided by aggressive pricing strategies designed to prod larger users toward far greater efficiencies.

As conservation’s critics rightly claim, any such move would impose immediate up-front costs on agricultural, commercial, and residential customers. Wealthier residents and larger companies could handle those costs; those who were poorer or smaller might not. The state could level the playing field, subsidizing certain improvements. That’s how low-flow toilets and solar panels have gotten into so many homes over the past ten years. But such  programs merely transfer costs from the richer Peters to the poorer Pauls.

In truth, though, economic arguments against conservation are highly disingenuous. Those who champion desalination have tacitly resigned themselves to the inevitable: Californians are going to pay more for the water they use.  If we can afford $15 billion to build desal plants, not to mention massively bloated water bills, then we can afford to do what it takes to conserve what we’ve got.

California’s frequent water shortages will inflict economic pain no matter what we do. We are now in the unfortunate position of choosing among poisons. We can only hope that the one we choose won’t kill the patient.

Meanwhile, in my front yard, our shade tree has found its own solution: send roots down into the mildly brackish water table, around twenty feet below the surface. From time to time, the tree also slips a couple of tendrils into the sewer pipe’s seams. Every couple of years, we hire a plumber and clean it out. It grows right back. There’s not a chance that I’ll take out the tree. It cools the house in the summer, shades the garden year-round and, by the way, saves on water. If the tree takes sometimes slakes its thirst with my used shower and toilet water, well, I’m happy to share.