Hell or High Water: How Will CA Adapt to the Anthropocene?
By Glen Martin
Photo courtesy California Magazine
On February 12, 2017, nearly 200,000 Californians got the order to flee for their lives. Record winter rains had filled Lake Oroville, the vast reservoir that anchors the California State Water Project, to the brim. To avoid overtopping, project managers had released massive quantities of water down Oroville Dam’s main spillway, but fissures in the concrete slabs that lined it were blown open by the torrents. The spillway was briefly closed to assess the newly formed crater, but repairs were impossible under the perilous conditions. The reservoir continued to rise. Water flowed over the wingwall atop the dam’s emergency spillway for the first time in the structure’s almost 50-year history.
The dam itself—at 770 feet high, the tallest in the country—was not at immediate risk. Collapse of the wingwall would be disaster enough, unleashing a 30-foot-high wall of water down the Feather and Sacramento Rivers, ultimately flooding large swaths of the city of Sacramento, blowing out levees in the Sacramento–San Joaquin Delta, and knocking out the gigantic pumps that send water to tens of millions of Southern Californians. Hundreds, maybe thousands of lives could be lost; the economic damage would spiral into the tens of billions of dollars or higher. The state’s electric grid could be impaired for months, and its water delivery infrastructure for years.
Just as the five-year drought had made it clear that California’s reservoirs were unable to store sufficient water to see the state through extended dry spells, so did last winter’s record-setting precipitation highlight the obverse: California’s dams and bypasses may not be adequate to prevent calamity during anomalously wet winters. It is especially sobering because most computer models indicate that extreme weather—droughts and floods—will be part of California’s future as the climate changes. The water storage and delivery system that more or less met needs from the 1950s to the 1960s, when the big dams and aqueducts were built, now seems lamentably inadequate in addressing the realities of the emergent geologic epoch: the Anthropocene.
Anthropocene is the voguish, and not yet officially adopted term, to describe the first geologic epoch in Earth’s history to be characterized primarily by the impacts of human activity, global warming foremost among them. To date, the societal response to climate change has mostly centered on efforts to reduce greenhouse gas emissions. But scientists concede that, even if we are fabulously successful at reducing emissions—and so far, CO2 levels continue to climb—concentrations of greenhouse gases in the atmosphere will increase for centuries to come. So, even as we struggle to wean ourselves off fossil fuel dependence, we will also have to adapt to its consequences.
Along with extreme weather events and climate swings, those consequences include rising sea levels, more and fiercer wildfires, and the rapid spread of vector-borne diseases. This winter’s crisis at Oroville was a disaster narrowly averted, but it should also be seen as a wake-up call of things to come.
California’s waterways -- including dams, rivers and deltas -- are also threatened by rising seas. According to a recent report by the National Oceanic and Atmospheric Administration, sea levels could climb by as much as 2.5 meters by 2100. As that happens, high tides could begin breaching the Sacramento delta’s outermost ring of levees; as they fail, the interior levees would follow suit.
The effects are not limited to the delta, of course. The US Geological Survey estimated that at 2 meters of sea-level rise, up to two-thirds of Southern California’s beaches would disappear. A 2012 report to the California Energy Commission concluded that even a 1.4-meter rise would put 270,000 people in the Bay/Delta at risk of displacement or death from a 100-year flood event, and destroy tens of billions of dollars in infrastructure.
Kristina Hill, Associate Professor of Landscape Architecture & Environmental Planning and Urban Design met recently with California Magazine at the Whole Foods Market near Oakland’s Lake Merritt to discuss what sea-level rise would look like locally. Certainly, there was no hint of looming disaster on this particular spring day. But in the not so distant future, Hill warned, the site will be decidedly less pleasant. In fact, she continued, it’s highly unlikely Whole Foods and most of the surrounding buildings will be here in 100 years—or even in 50. That’s because the surrounding low-lying landscape will be a swamp. And not a pretty, ecologically rich swamp with bromeliads, gnarled old willows, and clean water teeming with healthy fish and waterfowl. More like a New Jersey industrial corridor kind of swamp—ugly, toxic, and fetid.
“In a few decades, we’re likely to start seeing artesian springs bubbling out of the ground near us,” she explains, “but the water will be highly contaminated, not pure and sweet. All the pipes transporting sewage and chemicals under our feet here will be rupturing. Plus, we have tremendous loads of legacy contaminants in the fill all around the bay shore. It’ll be quite a mess.”
That scenario is assured due to both rising sea levels and the bay shore’s high water table, says Hill. “Fresh water floats on top of saline water,” she explains. “So you have a kind of doubling effect. As sea levels rise, there’s no place for the groundwater to go but up.”
Just how harsh or hellish this future becomes will largely depend on us. One response could be what planners are calling “strategic retreat.” Whole Foods, other retail outlets, and residents could relocate over time to higher ground, away from the encroaching waterline. Of course, that’s easier said than accomplished.
Seawalls are another alternative, but Hill is no fan of that idea, viewing concrete and steel barriers as expensive, environmentally destructive, isolating—and ultimately ineffective. “They fragment ecosystems and cut people off from the shoreline and water,” she says. “Plus, if you don’t plan correctly, they can be overtopped.” She cites recent research published in the journal Nature that predicts sea levels could be twice as high by 2100 as levels posited in earlier estimates. “So under the worst-case scenario, we’d get a 2-meter rise instead of a 1-meter rise. Obviously, if you built your seawall for 1 meter, you would be in deep trouble.”
With a 2-meter rise in sea level and little or no human response, Lake Merritt could expand and subsume parts of downtown Oakland; indeed, most of San Francisco Bay’s developed waterfront could turn into a series of wetlands and lagoons surrounding abandoned buildings and infrastructure. Retreat, strategic or otherwise, would be a foregone conclusion. That doesn’t mean we have to utterly abandon the bay shore, says Hill, but we do have to surrender the notion that we can keep things completely dry.
“We have to learn to live with water, not fear it, not try to completely exclude it,” she says. “You contour the land with drainage in mind, digging ponds and canals, and using the fill to construct berms and levees suitable for development. You’d have a honeycomb of ponds and canals, with miles of levees for potential development. You can also build homes and businesses on large floating structures rather than sinking piers. That way, you don’t lose your infrastructure due to overtopping.”
Hill points down Harrison Street, the busy thoroughfare next to Whole Foods. “If people are going to live around here a hundred years from now, Harrison Street will probably be a canal, draining groundwater to the bay,” she predicts. She unfolds some documents that include schematics of developments built atop broad berms next to idyllic ponds.
“Those homes and retail businesses on the levees would be prime real estate,” Hill observes. “The tax base they provide would be the funding mechanism for the flood control work. No one thinks the Netherlands is an unpleasant place to live. And like the Dutch, we would be building resilient urban areas—unlike New Orleans, for example, which I’d characterize as extremely brittle. No real lessons were learned from Katrina. They’re still relying on seawalls, pumps, and inadequate levees. They’re still incredibly vulnerable.”
Moreover, says Hill, “We could do it better than the Dutch. They don’t really think much about water quality or biodiversity. They have tremendous nutrient issues with their water. We could design for water quality and biodiversity by using wetlands as filtering system and wildlife habitat. We don’t just want homes along the bay. We want a healthy estuary, with Dungeness crab and salmon.”
Part of Hill’s grand view includes “shallowing” the bay: using the sediment obtained from dredging shipping channels to reduce the depth of the water right along the shoreline. This would allow for the establishment—or rather, reestablishment—of extensive salt marshes that would filter out contaminants, reduce wave action that could erode the outboard side of adjacent levees, and bolster fish and wildlife populations.
It’s a vision that’s both hopeful and pragmatic. But more than anything else, it requires regional planning, according to Mark Stacey, a Cal professor of civil and environmental engineering who researches estuarine and coastal physics. As sea levels rise and shorelines change, Stacey says communities will be forced to make major decisions on development and infrastructure. But if those decisions are made mainly at the local level—as is done currently—the problems aren’t mitigated, they’re intensified and moved down the shore or across the bay for someone else to address.
Instead, Stacey says, the bay’s shoreline communities should forge and abide by regional plans that accommodate rising water as much as possible and accept intermittent flooding as a simple fact of life. Communities that pursue a conjoined strategy, supporting projects such as those outlined for Oakland by Hill, can mitigate some of the effects of rising seas and gain some protection.
Yet, as daunting as the planning and engineering challenges are, perhaps an even greater issue is financing. All the diking and draining, the island building, the canal and pond excavation and bay shallowing envisioned by Hill and Stacey would cost hundreds of billions of dollars or more. How would Bay Area residents pay for it?
As outlined by Hill, assessing the high-end homes and businesses that would be built on the new levees could be part of the solution. Another idea garnering interest is a save now, build later strategy. “The idea is that you don’t build the levee now that you’ll need in 50 years,” Hill says. “Instead, you invest that money in the stock market. It grows dramatically through years or decades, and then you’ll have plenty of funds to build your projects when you absolutely need them.”
This approach has the advantage of avoiding projects that are quickly outdated, says Hill. “If we started constructing levees now for 2100, we could find that we weren’t ambitious enough, that sea-level rise could overtop our structures,” Hill says. “Our needs for 2100 will be clearer as we approach 2100. We don’t want to drag our feet, of course. But to get truly effective infrastructure, it might be better to build it quickly when the need is getting acute, not decades beforehand.”
How long can we wait to act? Oakland isn’t sinking under the waves just yet, but as demonstrated by the narrowly avoided catastrophe at Oroville, Anthropocene-induced risks to our water delivery systems and other critical infrastructure are already upon us. These systems are already showing multiple strains, and there could well be a domino effect if—or rather, when—one of them snaps.