The Mexican Water Treaty of 1944 committed the U.S. to deliver
1.5 million acre-feet of water to Mexico on an annual basis, plus
an additional 200,000 acre-feet under surplus conditions. The
treaty is overseen by the International Boundary and Water
Commission.
Colorado River water is delivered to Mexico at Morelos Dam,
located 1.1 miles downstream from where the California-Baja
California land boundary intersects the river. The river’s
natural terminus is the Gulf of California in Mexico, but because
of the dams and diversion facilities throughout the Colorado
River Basin, natural flow rarely reaches the Gulf. Water diverted
at Morelos Dam is primarily used to irrigate Mexicali Valley
farmland, and also supplies the cities of Mexicali, Tecate and
Tijuana.
… Since the 1970’s, untreated sewage flows have polluted the
[Tijuana] river, contaminating beaches from the California
communities of Coronado to La Jolla and disrupting both
military operations and civilian life. Generations of service
members stationed along the Silver Strand in San Diego County
have trained, lived and worked under the shadow of this
cross-border contamination problem. For Naval Special Warfare
units, the ocean is an operational environment. SEAL candidates
train daily in the surf zone, practicing timed swims,
underwater navigation and small-boat handling. When bacterial
counts spike, training is curtailed or moved, disrupting
schedules and adding logistical strain.
A binational analysis of data from 20 beaches on both sides of
the border shows fecal bacteria is present in the water and
exceeds health standards almost year-round. Over a two-year
period, One Coast Project and the Permanent Forum of Binational
Waters looked into water samples gathered since 1999 along the
coastline from Carlsbad, California, about 50 miles north of
the border, to Rosarito, Baja California, roughly 15 miles
south of Tijuana. The study found that in Southern California’s
beaches, the highest concentrations of enterococci bacteria
were reported during the spring, averaging over 15,000 units
per 100 milliliters of water, nearly 100 times the binational
legal limit average in both countries.
… Last month’s agreement to accelerate tackling the
long‑running sewage crisis in the Tijuana River
Valley is proof that — even now — quiet, institutional
diplomacy can deliver. … Since the 1983 La Paz
Agreement, the United States and Mexico have built a structured
framework for environmental cooperation. … In 2022, this
collaboration deepened with a memorandum of understanding and a
commitment from Mexico to invest $144 million in wastewater
infrastructure in the Tijuana River Watershed by 2027. … The
new agreement reinforces this prior commitment by prioritizing
the remaining $93 million and accelerating timelines,
reflecting a shared understanding that expanded infrastructure
and sustained operations are vital to protect public health and
ecosystems. –Written by Duncan Wood, CEO of Hurst International
Consulting in Washington, D.C., and Marie Elena Giner, former
commissioner for the International Boundary and Water
Commission.
This past rainy season, a trash boom in the Tijuana River kept
500 tons of plastics, trash and other debris away from the
Tijuana River Valley and the Pacific Ocean, far exceeding
expectations. On Tuesday morning, Oscar Romo, director of Alter
Terra, the non-profit in charge of the boom, gave a tour of the
area to members of the Rural Community Assistance Partnership,
one of the agencies that helped secure funding for the trash
boom. … For the time being, the boom has been dismantled
but will be reassembled and operational in a few months. “RCAP
was funded through the California State Water Board to have the
booms, deploy them for two storm seasons,” [Rural Community
Assistance Partnership Community Programs Director Jennifer]
Hazard said. “We were able to extend that to a third storm
season.”
Last week Mexico and the U.S. reached an agreement committing
both nations to expedite and solidify funding for projects
meant to curb the Tijuana River sewage crisis. [I]f both
countries keep their promises, the Tijuana and San Diego
communities could see significant progress in confronting a
problem that has long plagued them – billions of gallons of
untreated wastewater flowing through the Tijuana River
watershed past neighborhoods, and into the Pacific Ocean. The
projects on the agenda, however, are nothing
new. … While leaders and advocates are celebrating
the efforts from both governments to accomplish goals, they
also say more can be done and it remains unclear what recourse
there will be if either party fails to meet the timelines.
As climate change drives rising temperatures and changes in
rainfall, Mexico and the US are in the middle of a conflict
over water, putting an additional strain on their relationship.
Partly due to constant droughts, Mexico has struggled to
maintain its water deliveries for much of the last 25 years, in
keeping with a water-sharing agreement between the two
countries that has been in place since 1944 (agreements between
the two regulating water sharing have existed since the 19th
century). As part of this 1944 treaty, set up when water was
not as scarce as it is now, the two nations divide and share
the flows from three rivers (the Rio Grande, the Colorado and
the Tijuana) that range along their 2,000-mile border. The
process is overseen by the International Boundary and Water
Commission.
The governments of Mexico and the United States signed a
memorandum of understanding on Thursday to fund and expedite
several wastewater treatment projects in the Tijuana River
basin. Untreated wastewater continually affects residents
living along the river, which flows across the border from
Tijuana and through several of San Diego’s southern
neighborhoods. Residents living along the river have long
battled severe health issues which researchers say stem from
the river’s contamination. … In Thursday’s event
celebrated in Mexico City, US Environmental Protection Agency
Secretary Lee Zeldin and Mexico’s Secretary of the Environment
and National Resources of Mexico Alicia Bárcena agreed to a
series of actions to be taken by both governments by 2027 to
address the deteriorating wastewater treatment crisis.
Environmental Protection Agency Administrator Lee Zeldin
committed the Trump administration to “a permanent, 100%
solution to the decades-old Tijuana River sewage crisis” in a
new agreement signed with Mexico on Thursday.
… According to the agreement, Mexico will shake loose
$93 million in money it previously committed, known as “Minute
238 funds.” Deadlines for several long-discussed improvements
will also come sooner — some this year — it says. One example
is the 10-million gallons per day of treated effluent that
currently flows into the Tijuana River from the Arturo Herrera
and La Morita wastewater treatment plants and will now go to a
site upstream of the Rodriguez Dam, southeast of Tijuana.
… The MOU also commits the two countries to taking into
account Tijuana’s growing population, to make sure that
infrastructure improvements are not outstripped by changes on
the ground.
Scientists from UC San Diego’s Scripps Institution of
Oceanography have unveiled a tool that forecasts
sewage-contamination levels at beaches in south San Diego
County. It’s called the Pathogen Forecast
Model hosted by the Southern California Coastal Ocean
Observing System at Scripps. The Pathogen Forecast Model
website provides detailed estimates shoreline sewage
concentrations and the likelihood of swimmers getting sick for
Playas Tijuana, Imperial Beach, Silver Strand State Park, and
Coronado. … According to [Scripps oceanographer Falk]
Feddersen, the tool is the first of its kind in the nation that
responds to a longstanding problem of raw sewage from Mexico
circulating in the coastal ocean on both sides of the border.
… For decades, pollution from both sides of the U.S. / Mexico
border have seeped into the Tijuana River. These impacts have
only been made worse by climate change. From the border
community of Imperial Beach at California’s Southern tip,
reporter Philip Salata tells us more about how pollution,
history, politics, and environmental racism all add up to a
massive public health crisis. … [Salata:] This is actually a
seasonal river, normally dry for most of the year. Not anymore.
Now it flows year round with sewage. There’s been almost 1300
consecutive days of beach closures.
… The 1944 Water Treaty between the U.S. and Mexico was
signed in a different world, when rivers seemed eternal and
drought was merely a seasonal phenomenon. It obligated Mexico
to deliver 430 million cubic meters of water to the U.S. each
year, while the U.S. released over four times that amount to
Mexico from the Colorado River. But the math no longer
works. Mexico is now 1.5 billion cubic meters behind on
its side of the deal. The tributaries it relies on—especially
the Conchos—have dried. … Legal scholars at El
Colegio de la Frontera Norte argue the treaty must evolve.
Since 1944, basin populations have doubled, farming has
intensified, and the Rio Grande basin has warmed 1.3°C (2.3°F).
They propose adding a “flex clause” that would scale water
allocations to real-time climate and hydrological data.
However, U.S. officials fear that any renegotiation might
threaten Mexico’s Colorado River entitlements, which are
already shrinking due to record-low water levels at Lake Mead.
In the meantime, the treaty isn’t solving the conflict—it’s
deepening it.
After the thirtieth consecutive month without rain, the
townsfolk of San Francisco de Conchos in the northern Mexican
state of Chihuahua gather to plead for divine intervention. …
Under the terms of a 1944 water-sharing agreement, Mexico must
send 430 million cubic metres of water per year from the Rio
Grande to the US. … Following pressure from Republican
lawmakers in Texas, the Trump administration warned Mexico that
water could be withheld from the Colorado
River unless it fulfils its obligations under the
81-year-old treaty. … Since then, Mexico has transferred
an initial 75 million cubic metres of water to the US via their
shared dam, Amistad, located along the border, but that is just
a fraction of the roughly 1.5 billion cubic metres of Mexico’s
outstanding debt. … Farmers on the Mexican side read the
agreement differently. They say it only binds them to send
water north when Mexico can satisfy its own needs, and argue
that Chihuahua’s ongoing drought means there’s no excess
available.
… The odor comes from a toxic gas that’s colorless and smells
like rotten eggs. It’s hydrogen sulfide, or H2S, a byproduct of
the millions of gallons of untreated sewage from Mexico that
regularly chokes one of America’s most endangered rivers, the
Tijuana River. UC San Diego researchers,
led by Kim Prather, recently found that sewage-linked bacteria
and toxic chemicals in the river are airborne. In the past
couple of years, the volume of sewage flows, laced with
contaminated stormwater, noxious chemicals and trash, has been
the highest in the last quarter-century, worsening conditions
for those living and working nearby. … But the data remains
woefully insufficient to conclude what long-term exposure means
for individuals, especially for vulnerable groups such as
children or those with respiratory problems. And there are only
three monitors generating information for a border region that
is home to tens of thousands of residents who have raised
concerns for years.
Learn the history and challenges facing the West’s most dramatic
and developed river.
The Layperson’s Guide to the Colorado River Basin introduces the
1,450-mile river that sustains 40 million people and millions of
acres of farmland spanning seven states and parts of northern
Mexico.
The 28-page primer explains how the river’s water is shared and
managed as the Southwest transitions to a hotter and drier
climate.
Martha Guzman recalls those awful
days working on water and other issues as a deputy legislative
secretary for then-Gov. Jerry Brown. California was mired in a
recession and the state’s finances were deep in the red. Parks
were cut, schools were cut, programs were cut to try to balance a
troubled state budget in what she remembers as “that terrible
time.”
She now finds herself in a strikingly different position: As
administrator of the U.S. Environmental Protection Agency’s
Region 9, she has a mandate to address water challenges across
California, Nevada, Arizona and Hawaii and $1 billion to help pay
for it. It is the kind of funding, she said, that is usually
spread out over a decade. Guzman called it the “absolutely
greatest opportunity.”
Water is flowing once again
to the Colorado River’s delta in Mexico, a vast region that
was once a natural splendor before the iconic Western river was
dammed and diverted at the turn of the last century, essentially
turning the delta into a desert.
In 2012, the idea emerged that water could be intentionally sent
down the river to inundate the delta floodplain and regenerate
native cottonwood and willow trees, even in an overallocated
river system. Ultimately, dedicated flows of river water were
brokered under cooperative
efforts by the U.S. and Mexican governments.
For the bulk of her career, Jayne
Harkins has devoted her energy to issues associated with the
management of the Colorado River, both with the U.S. Bureau of
Reclamation and with the Colorado River Commission of Nevada.
Now her career is taking a different direction. Harkins, 58, was
appointed by President Trump last August to take the helm of the
United States section of the U.S.-Mexico agency that oversees
myriad water matters between the two countries as they seek to
sustainably manage the supply and water quality of the Colorado
River, including its once-thriving Delta in Mexico, and other
rivers the two countries share. She is the first woman to be
named the U.S. Commissioner of the International Boundary and
Water Commission for either the United States or Mexico in the
commission’s 129-year history.
Nowhere is the domino effect in
Western water policy played out more than on the Colorado River,
and specifically when it involves the Lower Basin states of
California, Nevada and Arizona. We are seeing that play out now
as the three states strive to forge a Drought Contingency Plan.
Yet that plan can’t be finalized until Arizona finds a unifying
voice between its major water players, an effort you can read
more about in the latest in-depth article of Western Water.
Even then, there are some issues to resolve just within
California.
It’s high-stakes time in Arizona. The state that depends on the
Colorado River to help supply its cities and farms — and is
first in line to absorb a shortage — is seeking a unified plan
for water supply management to join its Lower Basin neighbors,
California and Nevada, in a coordinated plan to preserve water
levels in Lake Mead before
they run too low.
If the lake’s elevation falls below 1,075 feet above sea level,
the secretary of the Interior would declare a shortage and
Arizona’s deliveries of Colorado River water would be reduced by
320,000 acre-feet. Arizona says that’s enough to serve about 1
million households in one year.
The Colorado River Delta once spanned nearly 2 million acres and
stretched from the northern tip of the Gulf of California in
Mexico to Southern California’s Salton Sea. Today it’s one-tenth
that size, yet still an important estuary, wildlife habitat and
farming region even though Colorado River flows rarely reach the
sea.
This issue of Western Water examines the ongoing effort
between the United States and Mexico to develop a
new agreement to the 1944 Treaty that will continue the
binational cooperation on constructing Colorado River
infrastructure, storing water in Lake Mead and providing instream
flows for the Colorado River Delta.
As vital as the Colorado River is to the United States and
Mexico, so is the ongoing process by which the two countries
develop unique agreements to better manage the river and balance
future competing needs.
The prospect is challenging. The river is over allocated as urban
areas and farmers seek to stretch every drop of their respective
supplies. Since a historic treaty between the two countries was
signed in 1944, the United States and Mexico have periodically
added a series of arrangements to the treaty called minutes that
aim to strengthen the binational ties while addressing important
water supply, water quality and environmental concerns.
California’s little-known New River has been called one of North
America’s most polluted. A closer look reveals the New River is
full of ironic twists: its pollution has long defied cleanup, yet
even in its degraded condition, the river is important to the
border economies of Mexicali and the Imperial Valley and a
lifeline that helps sustain the fragile Salton Sea ecosystem.
Now, after decades of inertia on its pollution problems, the New
River has emerged as an important test of binational cooperation
on border water issues. These issues were profiled in the 2004
PBS documentary Two Sides of a River.
Redesigned in 2017, this beautiful map depicts the seven
Western states that share the Colorado River with Mexico. The
Colorado River supplies water to nearly 40 million people in
Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming
and Mexico. Text on this beautiful, 24×36-inch map, which is
suitable for framing, explains the river’s apportionment, history
and the need to adapt its management for urban growth and
expected climate change impacts.
As part of the historic Colorado
River Delta, the Salton Sea regularly filled and dried for
thousands of years due to its elevation of 237 feet below
sea level.
The most recent version of the Salton Sea was formed in 1905 when
the Colorado River broke
through a series of dikes and flooded the seabed for two years,
creating California’s largest inland body of water. The
Salton Sea, which is saltier than the Pacific Ocean, includes 130
miles of shoreline and is larger than Lake Tahoe.
The Mexican Water Treaty of 1944 committed the U.S. to deliver
1.5 million acre-feet of water to Mexico on an annual basis, plus
an additional 200,000 acre-feet under surplus conditions. The
treaty is overseen by the International Boundary and Water
Commission.
Colorado River water is delivered to Mexico at Morelos Dam,
located 1.1 miles downstream from where the California-Baja
California land boundary intersects the river between the town of
Los Algodones in northwestern Mexico and Yuma County, Ariz.
The Colorado River Delta is located
at the natural terminus of the Colorado River at the Gulf of
California, just south of the U.S.-Mexico border. The desert
ecosystem was formed by silt flushed downstream from the Colorado
and fresh and brackish water mixing at the Gulf.
The Colorado River Delta once covered 9,650 square miles but has
shrunk to less than 1 percent of its original size due to
human-made water diversions.
This printed issue of Western Water examines how the various
stakeholders have begun working together to meet the planning
challenges for the Colorado River Basin, including agreements
with Mexico, increased use of conservation and water marketing,
and the goal of accomplishing binational environmental
restoration and water-sharing programs.
This printed issue of Western Water examines the
Colorado River Basin Water Supply and Demand Study and what its
finding might mean for the future of the lifeblood of the
Southwest.
This printed issue of Western Water explores some of the major
challenges facing Colorado River stakeholders: preparing for
climate change, forging U.S.-Mexico water supply solutions and
dealing with continued growth in the basins states. Much of the
content for this issue of Western Water came from the in-depth
panel discussions at the September 2009 Colorado River Symposium.
This printed copy of Western Water examines the Colorado River
Delta, its ecological significance and the lengths to which
international, state and local efforts are targeted and achieving
environmental restoration while recognizing the needs of the
entire river’s many users.
