Indus River Basin

Lake Victoria

The Nile River Basin

Salween River

Made with Natural Earth.

Al Sag Aquifer

Genevese Aquifer

Nubian Aquifer

North-west Sahara Aquifer

Made with Natural Earth.

Landsat images processed and compiled by Quartz

Landsat images processed and compiled by Quartz

The Rio Grande Valley of Texas is one of the fastest-growing places in the United States. Already hot and arid, and growing hotter, the booming, heavily Latino region depends almost entirely on the shriveling Rio Grande for water. Considered one of the most endangered rivers in North America, the Rio Grande provides drinking and irrigation water to 6 million people and 2 million acres of farmland on both sides of the Texas-Mexico border. Droughts and heat waves in the Valley are becoming more intense, exacerbating water scarcity.

Despite opinion surveys showing that Valley residents are deeply concerned about how climate change is affecting them, local and state officials are paying little heed to their constituents. According to a 2013 federal study (pdf), even before accounting for climate change the region is expected to run a "staggering" water supply shortage of almost 600,000 acre-feet in 2060. At the same time, some Texas border cities have been at the forefront of water conservation, and the US and Mexico have found ways to cooperate on protecting the Rio Grande.

This nine-part collaboration between the Texas Observer and Quartz explores the complexities of border water in search of answers for how people can work together in a hotter, drier world.

In November 2016, an unusual series of meetings took place on the banks of the Dead Sea, an ancient salt lake fed by the Jordan River.

An illustration of the US and Mexico representatives meeting with the Jordan representative.

First, three men from three sovereign states convened: one from Texas, in the US, one from Mexico, and one from Jordan.

An illustration of the US and Mexico meeting with Israel.

The next day, the two representatives from North America talked to a water manager from Israel.

An illustration of the US and Mexico meeting with Palestine.

And on the following day, the Texan and the Mexican met with the director of the Palestinian water authority.

The friendly meetings required three days, and three separate meetings, because Israel, Palestine, and Jordan have been fighting over water—and land—for decades.

Jordan River

Mediterranean

Sea

Sea of Galilee

West Bank

Jordan

Dead Sea

Israel

Israel, Jordan, and Palestine all share the Jordan River.

Jordan River

Mediterranean

Sea

Sea of Galilee

West

Bank

Jordan

Dead Sea

Israel

Israel, Jordan, and Palestine all share the Jordan River.

Jordan River

Sea of Galilee

Mediterranean

Sea

West Bank

Jordan

Dead Sea

Israel

Israel and Jordan share the Dead Sea.

Jordan River

Mediterranean

Sea

Sea of Galilee

West Bank

Jordan

Dead Sea

Israel

Israel and Jordan share the Dead Sea.

Jordan River

Mediterranean

Sea

Sea of Galilee

West

Bank

Jordan

Dead Sea

Israel

Israel and Jordan share the Dead Sea.

Jordan River

Sea of Galilee

Mediterranean

Sea

West Bank

Jordan

Dead Sea

Israel

Israel, Jordan, and Palestine all share the Jordan River.

Made with Natural Earth.

The water level in the Dead Sea is sinking perilously low as all three states pull water out of the Jordan River.

An illustration of three pipes pulling water out of the sea.

In 2013, Israel agreed to pipe between 8 billion and 13 billion gallons of water from its Sea of Galilee to Amman, the parched capital of Jordan, and to sell about 8 billion gallons of freshwater to Palestine at preferential prices.

In return, Jordan agreed to build a desalination plant, to transform salt water from the Red Sea into potable water; Israel and Jordan would both get between 8 billion and 13 billion gallons of that water. The salty mixture leftover from the desalination plant would be piped into the Dead Sea to replenish the beleaguered water body. The arrangement has been nicknamed the “Red-Dead” project.

An illustration of water flowing out of a pipe and into the sea.

The three states very rarely all meet, making the 2013 “Red-Dead” deal a diplomatic breakthrough. But, as of yet, no aspect of the agreement has been carried out, stalled by geopolitical tensions.

A defining characteristic of all three states is water scarcity. The region had just gone through the worst drought in 900 years, ending in 2012, and climate scientists believe the Middle East will become 40% drier by the end of the century. Israel, Jordan, and Palestine are geographically and hydrologically bound together, but the thwarted Red-Dead deal is a symptom of a broader illness: the three almost never all meet to talk.

That’s why the men from Texas and Mexico were there: Call it family therapy for water negotiators.

Texas and Mexico made for good mentors, since they have had to overcome geopolitical antagonism of their own to make sure the water kept flowing in the homes, businesses, and farms of their people.

More precisely, Ed Drusina, a Texan and the head of the US International Boundary and Water Commission at the time, had found a way to work closely with Roberto Salmón, the IBWC’s Mexico commissioner. They were both charged with negotiating the use of Rio Grande water, which is rapidly succumbing to the effects of climate change, to benefit their respective countries. They drank whiskey together, shared plates of mole at the Red Iguana in Salt Lake City, Utah, and sometimes even traveled together to meetings in the Middle East. Their spouses were friends.

An illustration of Drusina and Salmón dining at the Red Iguana.

Their countries, however, were mostly not. The same month the men met on the banks of the Dead Sea, the US elected a president who planned to build a wall along the Rio Grande and had falsely insinuated that those crossing into the US from Mexico are primarily drug dealers, criminals, and rapists.

An illustration of the two commissioners in front of the border fence.

Drusina and Salmón couldn’t afford to stop talking.

Colorado

New Mexico

Texas

Gulf of Mexico

Mexico

The Rio Grande

begins in the Rocky

Mountains, then

tumbles south

through Colorado

and New Mexico

until it hits Texas.

The Rio Grande begins in the Rocky Mountains,

then tumbles south through Colorado and New Mexico until it hits Texas.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

The Rio Grande begins in the Rocky

Mountains, then tumbles south through Colorado and New Mexico until it hits Texas.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

From there, the

remaining 1,250 miles (2,011 kilometers)

of the river define the Texas-Mexico border, from El Paso in the western tip of Texas to the river’s mouth at the Gulf of Mexico.

 

From there, the remaining 1,250 miles (2,011 kilometers) of the river define the Texas-Mexico border, from El Paso in the western tip of Texas to the river’s mouth at the Gulf of Mexico.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

From there, the remaining 1,250 miles (2,011 kilometers) of the river define

the Texas-Mexico border, from El Paso

in the western tip of Texas to the river’s mouth at the Gulf of Mexico.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

The northern segment of the river is fed from snowmelt in the mountains

of Colorado and New Mexico. In recent

decades, the snowpack

has decreased by about 25% as a result of the warming climate.

 

The northern segment of the river is fed from snowmelt in the mountains of Colorado and New Mexico. In recent decades, the snowpack has decreased by about 25% as a result of the warming climate.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

The northern segment of the river is fed from snowmelt in the mountains of

Colorado and New Mexico. In recent

decades, the snowpack has decreased by about 25% as a result of the warming

climate.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

By the time the river reaches Texas, most of the water has been used up by cities and farms.

 

 

By the time the river reaches Texas, most of the water has been used up by cities and farms.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

By the time the river reaches Texas, most of the water has been used up by cities and farms.

Colorado

New

Mexico

Texas

Mexico

Gulf of Mexico

Not far below El Paso, Texas, the Rio Grande runs dry for a few hundred miles.

El Paso

Not far below El Paso, Texas, the Rio Grande runs dry for a few hundred miles.

Colorado

New

Mexico

Texas

El Paso

Mexico

Gulf of Mexico

Not far below El Paso, Texas, the Rio Grande runs dry for a few hundred miles.

Colorado

New

Mexico

Texas

El Paso

Mexico

Gulf of Mexico

The second segment of the river is fed by the Rio Conchos, a Mexican tributary that flows north to the border. Both sides need the other.

Rio Conchos

The second segment of the river is fed by the Rio Conchos, a Mexican tributary that flows north to the border. Both sides need the other.

Colorado

New

Mexico

Texas

Rio Conchos

Mexico

Gulf of Mexico

The Rio Grande begins in the Rocky

Mountains, then tumbles south through Colorado and New Mexico until it hits Texas.

Colorado

New

Mexico

Texas

Rio Conchos

Mexico

Gulf of Mexico

Made with Natural Earth.

“The [IBWC] is 130 years old,” Salmón says. “We have survived different administrations. Both in Mexico and in the US. We’re still here.”

In 2017, the IBWC negotiated a new agreement over the Colorado River, which touches seven US states before tumbling into Mexico. It’s the crowning achievement of the last several years of IBWC negotiating. Mexico and the seven US states agreed to new conservation measures to mutually avoid catastrophic shortages. That’s what water negotiation can do when it works.

Colorado River

Wyoming

Nevada

Utah

Colorado

California

Arizona

New Mexico

Gulf of California

Mexico

Colorado River

Wyoming

Nevada

Utah

Colorado

California

Arizona

New Mexico

Gulf of California

Mexico

Colorado River

Wyoming

Nevada

Utah

Colorado

California

Arizona

New

Mexico

Mexico

Gulf of California

Made with Natural Earth.

“We sat at the same table, we shared the same whiskeys,” says Salmón. “And that worked. It’s still working.”

The two commissioners clink glasses in an illustration.

And that’s exactly what they advised the Palestinians, Jordanians, and Israelis. While the conflicts among the three countries span decades and are far greater than disagreements over water, Salmón believed a good first step to building trust—at least among the water negotiators—was to spend time together. Share a meal, he suggested. They weren’t going to solve decades of deep-seated tension, bellicose power dynamics, and violent conflict, but they could at least find common ground on water issues.

“I asked them how often they met,” Salmón recalls. “They said every two to three years. I said that’s not enough. Talk about your grandkids, and your kids. Things that are not related to water.”

But building the kind of relationship that existed between Salmón and Drusina takes years—and a less unstable political environment.

It can also take just hours to undo. On May 11, Ed Drusina heard through an IBWC lawyer that the Trump administration was asking him to step down. He had to vacate his position the same day. Sally Spener, a longtime IBWC employee and the current foreign affairs officer for the US side, called it a “normal presidential transition.” But other IBWC commissioners have stayed on despite changes in administration; the position is technical and not high profile, so it doesn’t typically get reshuffled like other presidential appointees.

It took Drusina by surprise. He’d been helming discussions between Mexico and Texas about adopting a new model for Rio Grande flows, so that both sides would be using the same scientific data to gauge how much water Mexico would be able to deliver to the US, and when. The departure was badly timed—the two sides were finally nearing an agreement. The Trump administration has yet to appoint a permanent US commissioner to replace Drusina, leaving a vacuum in a delicate situation, just as the Rio Grande Valley, the southernmost tip of Texas which lies along the northern bank of the Rio Grande, plunges into another drought.

Almost anywhere you look, the politics of border water are as tenuous as a spinning top. The slightest winds of change can send it careening off course. But when the countries’ interests align and relationships among key representatives, like the kind between Salmón and Drusina, have been carefully tended, the top can stay reasonably balanced, yielding cooperation over a shared resource.

Water doesn’t respect borders. Globally, 263 lakes and rivers are shared between at least two countries, according to the United Nations. Of the 195 states in the world, 145 have at least one of these international bodies of water, and must decide how to manage them with their neighbors. But two-thirds of border rivers in the world have no multinational agreements covering them in place. And in a warming world, freshwater is getting more scarce. That leaves hundreds of millions of border-adjacent people in a precarious state.

In addition to the lakes and rivers, at least 300 aquifers—stores of freshwater beneath the Earth’s surface—straddle international borders, according to the UN. That official count is likely low; it’s hard to map what you cannot see without expensive instruments and laborious analysis. The first official attempt to undertake transnational collaborative research on the boundaries of aquifers shared between the US and Mexico began in 2006. The joint research effort, under the auspices of the IBWC, is now coming to an end, having assessed only four of the dozens of potential aquifers, and the countries won’t even touch the idea of coming up with agreements to manage groundwater. Still, that baby step is a profound achievement in a world where groundwater often gets neglected.

Globally, only four international treaties exist governing transboundary aquifers, with one more agreed upon but not yet enforced.

Border conflicts over water have been a feature of life on Earth for centuries. But climate change is upping the ante. Freshwater is running out faster in dry places, and conflict is filling that void.

Right now, Chile is suing Bolivia, in the UN’s International Court of Justice in The Hague, over the Silala River. It’s a small waterway that flows west from Bolivia and crosses the border into Chile, where it feeds another river system that flows through the Atacama desert before tumbling into the Pacific Ocean.

Ascotán Aquifer

Silala River

Military camp

Bolivia

Chile

3 km

Ascotán Aquifer

Silala River

Military camp

Bolivia

Chile

3 km

Ascotán Aquifer

Military

camp

Silala River

Bolivia

Chile

3 km

Imagery provided by Planet Labs. Boundaries by Natural Earth.

Chile uses water from the Silala to feed mining operations in the Atacama. But the river starts with Bolivian springs. So now Bolivia is trying to charge Chile for the water, on the basis that the river is not a river at all. Instead, Bolivia claims it’s an artificial diversion created when a Chilean mining company built a canal in the 1990s, relying on a concession the Bolivian government revoked in 1997. Meanwhile, Chile claims the flow into its country is the natural course of the Silala, merely augmented, and not diverted, by the canal.

Ascotán Aquifer

Bolivia

Chile

San Pedro River

Silala River

Conchi Dam

10 km

Ascotán

Aquifer

Bolivia

Chile

San Pedro River

Silala River

Conchi Dam

10 km

Ascotán

Aquifer

Bolivia

Chile

San Pedro River

Conchi Dam

Silala River

10 km

Composite of Landsat 8 data. Boundaries by Natural Earth.

Exacerbating the conflict is climate change, which has caused Bolivia’s glaciers to shrink by over 40% in the last three decades. In 2016, the Bolivian government declared a state of emergency over water.

In the Horn of Africa, Ethiopia is nearing the completion of a massive hydroelectric dam on the Nile. The Grand Ethiopian Renaissance Dam is expected to cost anywhere from $4 billion to $6.4 billion and produce some 15 billion kilowatt hours of electricity, more than three times the electricity output of the Hoover Dam in the US.

Flows South

to North

Egypt

The Nile River

Sudan

Thickness is proportional to flow

Ethiopia

Lake

Tana

White

Nile

Blue Nile

South

Sudan

The

Sudd

DRC

Uganda

Lake

Albert

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Thickness is proportional to flow

Sudan

Ethiopia

Blue Nile

Lake Tana

White

Nile

South

Sudan

The Sudd

DRC

Lake

Albert

Uganda

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Sudan

Thickness is proportional to flow

Ethiopia

White

Nile

Blue Nile

Lake Tana

South

Sudan

The

Sudd

Lake

Albert

DRC

Lake

Kioga

Uganda

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Thickness is proportional to flow

Sudan

Ethiopia

Blue Nile

Lake Tana

White

Nile

Grand Ethiopian Renaissance Dam

South

Sudan

The Grand Ethiopian Renaissance Dam will have major impacts in a country where more than half the population lacks access to electricity.

The Sudd

DRC

Lake

Albert

Uganda

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Sudan

Thickness is proportional to flow

Ethiopia

White

Nile

Blue Nile

Lake Tana

Grand Ethiopian Renaissance Dam

South

Sudan

The Grand Ethiopian Renaissance Dam will have major impacts in

a country where more than half the population lacks

access to electricity.

The

Sudd

Lake

Albert

DRC

Lake

Kioga

Uganda

Lake

Victoria

Kenya

Tanzania

Flows South

to North

Egypt

The Nile River

Sudan

Thickness is proportional to flow

Ethiopia

Lake

Tana

White

Nile

Blue Nile

South

Sudan

Grand Ethiopian Renaissance Dam

The

Sudd

The Grand Ethiopian Renaissance Dam will have major impacts in a country where more than half the population lacks access to electricity.

DRC

Uganda

Lake

Albert

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

Flows South

to North

Egypt

The Nile River

Sudan

Thickness is proportional to flow

Ethiopia

Lake

Tana

White

Nile

Blue Nile

South

Sudan

Grand Ethiopian Renaissance Dam

The

Sudd

But the vast reservoir will take five to 15 years to fill up.

 

DRC

Uganda

Lake

Albert

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

Flows South

to North

Egypt

The Nile River

Sudan

Thickness is proportional to flow

Ethiopia

Lake

Tana

White

Nile

Blue Nile

South

Sudan

Grand Ethiopian Renaissance Dam

The

Sudd

During that time, flows from the Nile into Egypt could drop by as much as 25%.

 

 

 

DRC

Uganda

Lake

Albert

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Sudan

Thickness is proportional to flow

Ethiopia

White

Nile

Blue Nile

Lake Tana

Grand Ethiopian Renaissance Dam

South

Sudan

But the vast reservoir

will take five to 15 years

to fill up.

 

The

Sudd

Lake

Albert

DRC

Lake

Kioga

Uganda

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Sudan

Thickness is proportional to flow

Ethiopia

White

Nile

Blue Nile

Lake Tana

Grand Ethiopian Renaissance Dam

South

Sudan

During that time, flows from the Nile into Egypt could drop by as much as 25%.

 

 

 

The

Sudd

Lake

Albert

DRC

Lake

Kioga

Uganda

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Thickness is proportional to flow

Sudan

Ethiopia

Blue Nile

Lake Tana

White

Nile

Grand Ethiopian Renaissance Dam

South

Sudan

But the vast reservoir will take five to 15 years to fill up.

 

The Sudd

DRC

Lake

Albert

Uganda

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

The Nile River

Flows South

to North

Egypt

Thickness is proportional to flow

Sudan

Ethiopia

Blue Nile

Lake Tana

White

Nile

Grand Ethiopian Renaissance Dam

South

Sudan

During that time, flows from the Nile into Egypt could drop by as much as 25%.

 

 

 

The Sudd

DRC

Lake

Albert

Uganda

Lake

Kioga

Lake

Victoria

Kenya

Tanzania

About 85% of the water used in Egypt comes from the river and experts expect the country to face a nationwide freshwater shortage by 2025. Researchers also expect climate change will make the river’s flow 50% more variable, swinging from drought one year to flooding the next and making the dam more difficult to operate.

In 2013, former Egyptian president Mohamed Morsi was caught on camera proposing military strikes in response to the potential project. Last month, Ethiopia’s chief engineer on the dam was found dead from a gunshot wound to his head in his car. Talks between Ethiopia and Egypt are still deadlocked. "If the water that's coming to Egypt reduced by 2%, we would lose about 200,000 acres of land. One acre at least makes one family survive. A family in Egypt is average...about five persons. So this means about 1 million will be jobless,” Mohamed Abdel Aty, Egypt's minister of water resources and irrigation, told the BBC in January. "It is an international security issue."

In the spring of 2013, the situation along the southern end of the Texas-Mexico border reached a boiling point. The flow in the Rio Grande had dropped so much that farmers and city residents alike were facing empty hoses and taps.

Texas officials mostly laid the blame at the feet of the Mexicans. While Mexican officials claimed they had technically met their treaty obligations, the Americans charged that Mexico had failed to release enough water behind its dams into the Rio Grande.

Rio Grande

Colorado

Flows North

to South

Albuquerque

Thickness is proportional to flow

Elephant

Butte

Caballo

Pecos River

Texas

El Paso

New Mexico

Rio Conchos

Devils River

Amistad

Reservoir

Mexico

United States

Falcon

Reservoir

Rio San Juan

El Azucar

McAllen

Rio Grande

Colorado

Flows North

to South

Albuquerque

Elephant

Butte

Thickness is

proportional to flow

Caballo

Pecos River

Texas

El Paso

New Mexico

Mexico

Rio Conchos

United States

Devils River

Amistad

Reservoir

Falcon

Reservoir

Rio San Juan

El Azucar

McAllen

Rio Grande

Colorado

Flows North

to South

Albuquerque

Elephant

Butte

Thickness is

proportional to flow

Pecos River

Caballo

Texas

El Paso

New Mexico

Rio

Conchos

Devils River

Amistad

Reservoir

Mexico

United States

El Azucar

Falcon

Reservoir

Rio San Juan

McAllen

But there are signs of cooperation, too. The Mexican and US teams of the International Boundary and Water Commission are working together to develop a complete flow model of the Rio Grande along the border, the first to be agreed upon by both sides.

The model, they hope, will clear up the he-said-she-said nature of water deliveries; based on rainfall and other factors, both sides would look to the model to decide if deliveries are feasible at any given time. Sally Spener, the foreign affairs officer for the US side of the IBWC, calls it a “technical, science-based decision-making tool.” It could also be called a means to enact the old adage of “trust, but verify.”

Aaron Wolf, a professor at Oregon State University, has spent most of the last three decades compiling evidence that undermines conventional wisdom: Yes, water causes conflict, especially when two or more countries share it, and especially when it’s running out—but in the majority of cases, conflicts can be mitigated or resolved through mediation and cooperation. In fact, he says, one could look at water as the most potent driver of international dispute settlement. “I started counting stuff in the early 1990s,” says Wolf. “At the time, the going theme was water wars—that they were inevitable, common, on the horizon. But nobody could reference one. I started digging around and couldn’t find a war over water since 2500 BC,” when the city-states of Lagash and Umma fought over the Tigris River.

Wolf and his colleagues combed through thousands of newspaper clippings and historical accounts of anything having to do with water at international borders. He ranked every event on a scale of -7 to +7, with numbers below zero indicating worsening degrees of conflict, and numbers above zero pointing to increasing degrees of collaboration. “It turns out two-thirds of the time we do anything over water, we cooperate,” Wolf says. “There was a whole rich history that isn’t covered anywhere.”

Shared water dispute severity, 1948 - 2008

2,000 events

1,750

1,500

1,250

1,000

750

500

250

0

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

Conflict

Cooperation

Quartz | qz.com

Data: International Water Events Database

Shared water dispute severity, 1948 - 2008

2,000 events

1,500

1,000

500

0

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

Conflict

Cooperation

Data: International Water Events Database

Quartz | qz.com

Shared water dispute severity,

1948 - 2008

Frequency

0

.5

1

1.5

2k

7

6

Cooperation

5

4

3

2

1

0

-1

-2

-3

Conflict

-4

-5

-6

-7

Data: International Water Events Database

Quartz | qz.com

He argues that the narrative about water conflict exists mostly because the world looks away too soon. Threats of violence draw headlines, and those same headlines force countries to start problem-solving, often together. Water treaties, Wolf says, tend to stand the test of even war. In the midst of war between India and Pakistan in 1965, 1971, and 1999, for example, India upheld its end of the Indus water treaty by delivering water to Pakistan. “From time to time, somebody will find it in their political interest to say, ‘We need to stop collaborating with the enemy,’ or whatever,” Wolf says. “[But] if you deny someone water, you’re basically using it as a weapon of mass destruction. You’re targeting civilians.” More often than not, the threat tops out at political bluster.

Now, Wolf is using his news-tracking strategy to find where border-water conflict is likely to arise next. These are mostly places where countries have plans for dams but have yet to bother talking to their downstream neighbors. For example, on the Salween River—a basin twice the size of England that’s shared between China, Myanmar, and Thailand—China is planning five mega-dam projects that would likely impact how much of the river makes it to Myanmar. The Salween basin is expected to face more intense rainfall events in the future, which environmentalists fear will put the dams at risk of failure. Still, China is marching ahead with plans for construction and Wolf expects that situation to flare up soon.

Sometimes collaborations are far more informal. In Nogales, a border city in Sonora, Mexico, there’s a hotel connected to a water pipe that snakes across the border to Nogales, Arizona. The Hotel Fray Marcos, on the Mexican side, pays the water utility in Nogales, Arizona, $5.53 per 1,000 gallons, plus a monthly service charge of $80.93. Lately, they’ve been buying about 150,000 gallons per month from their US neighbor, according to Angel Suarez, the revenue manager for the Nogales, Arizona, water utility.

N

Water main at border

United States

Mexico

Hotel Fray Marcos

50 m

N

Water main at border

United States

Mexico

Hotel Fray Marcos

50 m

N

Water main at border

United States

Mexico

Hotel Fray Marcos

50 m

Satellite image ©2018 DigitalGlobe. Boundaries by Natural Earth.

Suarez doesn’t know how long the hotel has been a customer—it predates the utility’s computerized records—but it’s been a long time, back when the border was more a symbol than a fortification, when there was “barely a fence” between the two, he says.

A nondescript backflow pipe and water meter installed in the 1990s is still clearly visible on the US side—the pipe quite literally runs through a hole in the border wall. It would likely be impossible to install another system like that today. “I’ve heard of customers across the line trying to get water from us and it hasn’t been approved,” he says. “I’m guessing this was grandfathered in.”

Angelo Lavo

“The system is not hidden,” Violeta Mendoza, a water engineer at Arizona State University, wrote in a report on informal transboundary water agreements in 2012. “It is very likely that the IBWC knew about the installation of this system, especially since its construction and installation took place right at the border and IBWC has representatives in Nogales.”

But whatever cooperation exists between the US and Mexico is likely to be challenged by the new sections of border wall now being planned by the Trump administration. Earlier this year, Congress appropriated $641 million to build between 33 miles of border wall in the lower Rio Grande Valley, and US Customs and Border Protection appears to be moving forward with construction. Some landowners in the region have already received notices from the agency about private land seizures.

Walls act like dams. Environmental advocates and the Mexican officials with the IBWC worry that during severe rainfall events additional fencing could hold water back from flowing to the river, exacerbating flooding in the Valley and in Mexico.

A 1970 treaty between Mexico and the US stipulates that the two sides must reach an agreement before either can build any structure that could impede the Rio Grande’s floodwaters. While the IBWC did note in 2010 that additional sections of border wall could result in “substantial increases” in floodwaters, the agency later backtracked and supported expanding the wall.

But other parts of the border along the Rio Grande have already seen what can happen when heavy rain hits sections of fence: The border crossing between Lukeville, Arizona, and Sontoya, Mexico, flooded in 2008 after a hastily-built section of border wall backed up stormwater on the US side. That same year, in Nogales, Arizona, water rose ankle-deep—but right across the fence in Nogales, Mexico, water reached the tops of door frames. Cars piled up against the border wall. Floodwaters killed two people.

Even sections of wall designed specifically to allow water to pass through have not proven immune to floods. In 2014, another round of heavy rainfall in the Nogales area caused debris to pile up against the border fence, causing it to act like a dam. The floodwaters were so powerful they knocked the fence over.

Managing a river shared by two countries is challenging enough. Add to that historically volatile relationships, booming populations, longer and more intense droughts driven by climate change, and the growth of industries dependant on the river for water, and you have—well, you basically have the river-border between Texas and Mexico.

Water doesn’t recognize borders, but border politics around the world often sink or swim based on water. Relationships between countries are shifting as climate change accelerates and freshwater becomes ever more precious. When every drop is accounted for, every drop will be fought over—but the need to stretch resources will also open rare windows to diplomacy. In this nine-part series, we’ll look at how the US and Mexico are confronting their slippery interdependence when it comes to the one thing neither side can do without.

This is the first article in a series on border water and climate change, the result of a partnership between Quartz and the Texas Observer. Part of the reporting for this project was supported with a collaborative reporting grant from the Center for Cooperative Media. Additional reporting by Angelo Lavo, production by Sunny Sone, and assistance from Amanda Shendruk. Original illustrations by Llew Mejia. Edited by Elijah Wolfson and Forrest Wilder.