Water Always Wins

Subterranean explorers, featured in a 2012 film called Lost Rivers, are discovering buried waterways encased in pipes below Toronto, Montreal, and Brescia, Italy.

In late 2016, just as the thirst was growing truly desperate, the atmospheric rivers arrived. These enormous trains of condensed vapor move from west to east across the Pacific like rivers in the sky, 1,200 to 6,000 miles long and capable of carrying fifteen times the average flow at the mouth of the Mississippi. When they hit mountains in California, they can dump hurricane quantities of rain. Storms borne on atmospheric rivers are not new in the state, but they are increasing in frequency worldwide, likely doubling by the end of this century. And as Earth continues to warm, models show that atmospheric rivers in California will hold an estimated 10 to 40 percent more water, increasing the risk of floods and mudslides. Fifteen of these strong atmospheric rivers hit California during the winter of 2016–17, turning hillsides so sodden that they slid down over roads.

Oceans have absorbed more than 90 percent of the excess heat since the 1970s. Warmer seawater, especially in tropical areas, evaporates more readily, increasing air temperature and humidity, leading to increased rain in some areas. Warmer air also evaporates more water out of soil and freshwater bodies and allows the atmosphere to hold more water. That’s because the molecules of vapor are moving faster than those in colder air, making them less likely to condense back into liquid to fall as rain. For each Celsius-degree increase of warming, the air holds about 7 percent more vapor. And because water vapor is itself a greenhouse gas, more water in the air creates a feedback loop, further warming the globe and accelerating climate change. But while some places are getting more rain, others are experiencing increased water scarcity. Warmer temperatures are also drying out the land through evapotranspiration.

UN demographers say the planet will hit around 10.9 billion humans by 2100. (The well-established path to slowing population growth includes access to birth control and education for women and making it acceptable—in all cultures—to have one or zero kids.)

Along coasts, pumping groundwater can create a vacuum that pulls seawater inland underground, turning crop land saline, a phenomenon happening now in many places, including Vietnam and Oceanic nations such as Kiribati, Tuvalu, and the Marshall Islands.

dams are often built to supply water, they end up creating water haves and have-nots by moving water from one area to another. And they increase water demand among the haves by holding that “new water” in a big lake, giving people a false sense of bounty that encourages waste.

Most large dams around the world were built between 1930 and 1970, with a design life of fifty to a hundred years.

Water’s ancient negotiations with rock and soil created these historic riverbeds, called paleo valleys, that lie hidden underneath us. Because they are more permeable than surrounding material, they are still the pathways that water wants to travel underground. Only three have been discovered so far in California. Hydrogeologist Graham Fogg has a dream: to find more of these paleo valleys and use them as giant drains that can absorb water from today’s heavier winter storms and store it underground.

Eighty percent of water used by humans in the state goes to irrigate California’s $ 38 billion crop industry, which supplies more than a third of US vegetables, two-thirds of its fruits and nuts, and international markets. This bounty is made possible by tapping groundwater and micromanaging a vast complex of water-engineering projects: dams, reservoirs, aqueducts, canals, levees, and pumps that have fundamentally changed the natural hydrology of the entire state and caused countless unintended consequences. The San Joaquin River is so diverted that, for more than a half century, it often ran dry for sixty miles. Beyond that, starting at the Mendota Pool, the water coursing through its banks was not even its own. One water expert called the Central Valley “the least wild landscape imaginable.”

Throughout the clay-dominant substrate, imagine that the paleo valleys are like mainline blood vessels of the groundwater system, with myriad branches tentacling off like capillaries. As the groundwater moves through these channels filled with sand and gravel, it is also moving in and out of the surrounding clays and silts. Fogg extends the metaphor of our body tissues: “The fluids in your body move through veins and arteries relatively quickly. But most of your body is these soft tissues that are primarily water; the water moves in and out of these more slowly, by molecular diffusion and other processes.”

Fogg thinks the most useful paleo valleys for groundwater recharge are the most recent because they are closest to the surface—perhaps just a yard or two down. They would allow water to move rapidly underground compared with the vast majority of the surface area that has much slower infiltration rates due to the widespread presence of silt and clay.

In 2005, one of Weissmann’s grad students, Amy Lansdale Kephart, went through ten thousand well logs and discovered another paleo valley near Modesto. She built a 3-D map with the data and modeled how water would flow through it and how useful it could be for water storage. The Modesto paleo valley is about 0.4 to 1 mile wide and 10 to 98 feet thick. She found it could influence groundwater flow, attracting water into it or pushing water out of it, for around 12.4 miles on either side of the valley and for hundreds of feet in depth. A student of Fogg’s, Casey Meirovitz, found a third paleo valley near Sacramento in 2017. Then, in 2019, Fogg’s student Steven Maples showed that it could accommodate almost sixty times more water than surrounding lands. “It’s a shame that we still don’t know where the rest of them are in California,” says Fogg in his mild way. “This should be a priority.”

(An acre-foot is the quantity of water needed to flood an acre of land a foot deep. It pencils out to 325,851 gallons.)

farmers and their lobby are typically distrustful of Big State Government. (Although that’s ironic, given that they benefit from state and federal largesse. As author Marc Reisner puts it in his classic tome on Western water, Cadillac Desert: “With huge dams built for him at public expense, and irrigation canals, and the water sold for a quarter of a cent per ton—a price which guaranteed that little of the public’s investment would ever be paid back—the West’s yeoman farmer became the embodiment of the welfare state, though he was the last to recognize it.”)

Fogg thinks that airborne EM will be “game changing” for finding the rest of the paleo valleys in California. But after getting a general idea of where they are, people will still need to map detailed information about them either with higher-density airborne surveys or the old-school way, with data from drilled wells. The latter should be easier now too. That data used to be proprietary. Whenever the legislature tried to submit a bill to make the information public, it met an implacable wall of resistance from industry, Fogg tells me. Now, thanks to a recent law, it’s available to everyone; but he’s found it to be in disarray. “It needs a fair amount of analysis and triage” to be more useful for groundwater science and management. Fogg would like to see a state agency sort this data into categories of “good, bad, and ugly.” In recent years, he has been advocating for the California Geological Survey to take up mapping for water resources, shifting from its historical focus on mining, oil, and gas to the preeminent resource today.

Wetlands are places where water stalls on the land at least part of the year, or where the water table is high enough to support plants who like wet roots. There are four main kinds: marsh, swamp, bog, and fen. Which name applies depends on whether they lie by a river, lake, or ocean or are isolated from other water; the soil and geology; whether they’re fed by rain, surface water, or groundwater; and what types of dissolved matter they contain that influence the water chemistry. All these factors affect which plants can grow, creating different ecosystems.

Wetlands also store atmospheric carbon dioxide captured via photosynthesis in their decomposed plants, especially those that stay wet the longest. That’s why peat is a superstorer of carbon. Although just 3 percent of Earth’s land is covered in peat, it holds 30 percent of land-based carbon dioxide.

Here on the West Devon site, beavers now number five, and they have constructed thirteen dams, creating thirteen ponds across their territory between 2011 and 2016. In slowing the water and spreading it laterally from the original stream, they have expanded the wetland area from about one thousand square feet to twenty thousand square feet. Together the ponds hold up to 264,000 gallons of additional water above ground. Since then, the beavers have not built additional ponds, but they continue to adjust the height and width of their dams, and the volume of water on the site continues to rise.

Building a levee on one bank pushes high waters onto the opposite bank, launching an engineering arms race. People on the other side build levees too, and the water, confined to an unnaturally narrow channel, unable to spread and slow upon its floodplains and wetlands, rises up and flows faster. The longer the length of levees, the greater the constriction, the higher and faster the water, the worse the flooding becomes downstream and at every place where a levee breaks. A narrowed river can even cause flooding upstream by creating a bottleneck. The US General Accounting Office acknowledged these hydrological truths with regard to both the Missouri and Mississippi Rivers in 1995: “That levees increase flood levels is subject to little disagreement.” Studies noted that flood levels near St. Louis had increased up to thirteen feet over the twentieth century. Unfortunately, these effects are generally recognized only in hindsight because proposed levees are evaluated individually without considering the cumulative effects of many projects along the length of a river.

A few places along the 2019 flood course had previously taken a Slow Water approach. Davenport, Iowa, which sits along the Mississippi River, decided in the early 2000s to restore Nahant Marsh, a 305-acre wetland right near the urban area, and to use riverfront parks to accommodate high flows. In 2019, Nahant Marsh absorbed as much as a trillion gallons of floodwaters, protecting much of Davenport. Eventually part of the downtown flooded, but the damage was much less severe than it was elsewhere. Marsh managers bought an additional thirty-nine acres of farmland in 2018 between Nahant Marsh and the Mississippi River, restoring it to wetlands and prairie. Now they are looking for more. The city is embracing the wisdom of a local professor of civil and environment engineering to “let floodplains be floodplains.”

Like many of the water detectives I met, they use spatial mapping software from Environmental Systems Research Institute. ESRI was founded by a low-key, humble guy named Jack Dangermond and his wife Laura. Jack Dangermond grew up in Southern California in the mid-twentieth century. His parents owned a plant nursery and the whole family spent a lot of time in nature. Like Yu, Dangermond also studied landscape architecture at Harvard (though a bit earlier), where he was introduced to making maps on computers. He realized there was a database underneath the maps, and this inspired him to build databases that would allow him to model natural processes and human behavior. ESRI can map watersheds from mountains to ocean, modeling floods, plant succession, infrastructure, and much more to help us move beyond single-issue problem solving. The tool allows us to get our minds around complex systems and their interrelated challenges, such as how to prevent biodiversity loss, build smarter cities, and reduce resource waste. A specialized add-on called arcHydro includes data from hydrologists to better predict rainfall and flooding.

historical maps show that, over time, buildings come and go. In the United States, many are replaced after fifty years. In rapid-growth places like China, that turnover may happen in just fifteen years (although the average is about thirty years). That presents enormous opportunities to redesign buildings and urban systems to scale up nature-based processes as needed and as urban remodeling allows. Disasters can also serve as a catalyst for urban change, such as when governments use emergency funds to buy victims out of a floodplain, remove buildings, and convert the area to an absorbent park. Reclaiming derelict industrial sites along rivers can also clear a lot of important space for water.

Plants on decks off the bedrooms are watered with roof-caught rain, stored in tanks under the raised plant beds.

The size of the continent is difficult to grasp. Its fifty-four countries span an area almost twice the size of Russia, or more than three times the size of the United States. Today Africa’s population is 1.3 billion people. Compared with, say, India, where more than 1.4 billion occupy just one-tenth the area, that means there’s still a lot of room for other species. That Africa still has so much of its natural landscapes, including more free-flowing freshwater systems remaining than any other continent, is why its large mammals—elephants, giraffes, cheetahs, lions, gorillas, chimpanzees, rhinos—still survive here, for now.

New York City famously bought 1,600 square miles of land in the Catskill Mountains for $ 1.5 billion in 1997 to protect and clean its water, rather than invest in an expensive new water treatment plant that it estimated would cost more than $ 6 billion plus $ 250 million a year for maintenance. It was cheaper to protect the forest. Often, conserving watersheds can be less expensive than destructive alternatives to supply water, such as desalination plants or new reservoirs formed behind dams.

in 1979, Brazilian meteorologist Eneas Salati, using the fact that water from different sources has different chemical signatures, showed that half the rain in the Amazon rainforest came from the trees themselves. Trees can also generate rain far away: the Ama-zon produces precipitation as far away as Texas; the Congo forest waters the US Midwest; forests in Southeast Asia influence rain in the Balkans. The flip side—as Kenyan farmers have witnessed firsthand and which has been borne out in studies—is that deforestation can reduce rainfall magnitude.

SFEI often starts with nineteenth-century US Geographic Survey topographic maps and hydrologic surveys, coastal navigation maps, historical and modern aerial photographs, and century-old maps from the US Department of Agriculture demarcating thirty different types of soil. (The latter is a good indicator of water capacity and vegetation and habitat type.) Then the historical ecologists add their archival finds, weighted to reflect their confidence in each bit. Their approach has been taken up and adapted by others in this small field in different regions. Fortified with these detailed maps of what once was, detectives can understand what water wants in a particular place and look for opportunities to accommodate it.

In the future, if ecologists need to feed sediment to living marshes to keep up with sea-level rise, they will need a delicate way to do that to maintain marsh health. Scientists are hoping to use local tides to distribute it, a process called “strategic placement.” Another SFEI geomorphologist and other researchers looked at two approaches. One would inject sediment into daily flood tides, allowing them to move it onto the marsh. Called water-column seeding, it would be more in sync with how nature does it than pumping in slurry. But it limits the hours in which sediment can be moved and, thus, its delivery rate. The other method, called shallow-water placement, would dump sediment into shallow water or onto a mudflat so waves and tidal currents can deliver sediment to the marsh in their own time. But with this approach, animals living in the mud may be smothered. Now shallow-water placement is being tested by the Army Corps of Engineers. Scientists will monitor potential harm to those mud dwellers and measure how much deployed sediment actually lands on marshes targeted for restoration.

California’s state legislature proposed buying doomed properties, then renting them out until they were no longer usable, to recoup some funds. Unfortunately, Governor Newsom vetoed it.

severe drought from 2014 to the present wiped out harvests and killed livestock in Central America, especially Honduras, Guatemala, and El Salvador, making millions go hungry and forcing people off their land. Many joined the migrant caravans pushing toward the United States since 2018.

The future may see migration away from these water-insecure places toward those that are rich with water, such as the United States around the Great Lakes, Canada, Russia, Scandinavia. Unfortunately, one early outcome is not moving but water grabbing. And this phenomenon is not exclusively limited to targeting poorer countries such as Kenya. Saudi Arabia has bought up ten thousand acres in Arizona to grow hay to feed cows at home with subsidized, unsustainable water.

In Thailand, people put bundles of bamboo under their homes to act as rafts when the water comes, tying buildings to trees so they don’t float away. Along the Maas River in the Netherlands, some Dutch houses sit on hollow, buoyant foundations and are tethered to pillars so they can rise and fall with the rhythms of the water. This option excited English because it works for houses with electricity and running water.

She and her students at the Buoyant Foundation Project took that basic idea and tweaked it to make it workable in various cultures and ecosystems. For places like the United States and Canada, they suggest using plastic water barrels, foam buoyancy blocks, or manufactured dock floats. They put the floaters inside a structural subframe under the house. The subframe and home are affixed to vertical guideposts sunk into the ground, allowing the house to rise and fall without floating away from its foundation. The homes may be designed with coiled “umbilical lines” for water supply and electricity, and breakaway connections for gas and sewer lines. The cost of a buoyancy system is around $ 15–$ 40 per square foot. There are no mechanical parts. The water does the work, lifting the house.