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Will Texas actually run out of water? Your questions about the state’s water supply answered.

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Friday, November 7, 2025

Subscribe to The Y’all — a weekly dispatch about the people, places and policies defining Texas, produced by Texas Tribune journalists living in communities across the state. Audio recording is automated for accessibility. Humans wrote and edited the story. See our AI policy, and give us feedback. For most of this year, Texas Tribune reporters have aggressively reported on the state’s water supply crisis. As part of our special report, Running Out, we created a chatbot that we trained to answer your questions based on our reporting. Y’all asked a lot of questions! And in some instances, the bot could not answer those questions. Technology! Can’t live with it, can’t live without it. Those queries were sent to us. We read each one and began saw some themes. Many of you had specific questions about your own region. If you still do, you can use this tool to look up the water situation in your county. Many of you wanted to know when the state was going to run out of water, who is in charge, and how much we should worry about climate change. We identified the six most commonly asked questions and answered them below. Texas voters this week once again voted overwhelmingly to fund water projects for the next 20 years. As the Tribune reported, the money will help. And yet, the $20 billion sum falls far short of what might be needed. Our reporting on the state’s water supply and the looming crisis will not end, even as this year comes to a close. Keep the questions and story ideas coming. Will Texas actually run out of water? There are some scary estimates out there. The Texas Water Development Board projects in the state’s 2022 water plan that towns and cities could be on a path toward a severe shortage of water by 2030. This means everything, from drinking water to wastewater, and water for agricultural uses, could run low in the next few years. However, there are several factors that go into that, including if there is a recurring, record-breaking drought across the state and if water entities and state leaders fail to put key strategies in place to secure water supplies. Those strategies range from creating new sources of water supply — think desalination, conservation, and aquifer storage and recovery — to fixing the failing infrastructure that causes water lines to break and gush water out all around the state. Other estimates give us a little more time, but don’t look much better. The state water plan projects that groundwater availability, which is found underground in aquifers, makes up half of the state’s water supply, will drop by 25% by 2070. Our total water supply — groundwater paired with surface water — is estimated to decline by 18% by the same year, in part because of how many people are expected to live in Texas by then. This is why advocates say the dedicated funding approved by voters this year was so critical. That money goes toward repairing aging infrastructure and projects that create the new sources of water supply that the future of the state will rely on. What are the most affected regions in Texas by water shortages and why? Texas has 16 regions for water planning. Each faces unique challenges and are tasked with managing their own water supply. Generally, East Texas is more lush and water-rich, while West Texas is much dried. South Texas, especially the Rio Grande Valley, has been plagued by an ongoing drought. A binational tussle over water with Mexico, also isn’t helping the region. All of Texas water supply is impacted by a combination of the following: limited supplies, population growth, and climate pressures. In their planning, regional leaders are supposed to project their water supply and water demand for the following years to come. Since water supply varies by region, the Texas Tribune created an address-search tool based on that data. This tool shows where your local water supply comes from and what supply and demand projections look like for the future. You can find it here. What role does the Texas Commission on Environmental Quality play in protecting the state’s water supply? Surface water — the stuff in lakes and rivers — in Texas is owned by the state. The TCEQ, the state’s environmental regulator, oversees those rights. Since 1967, the TCEQ has issued permits granting farmers, ranchers, cities, industries, and businesses the right to use it. These permits are issued on a “first come, first served” basis, with each one assigned a priority date that determines seniority. During droughts, permit holders with the earliest dates have the right to get water before those with newer dates. Each permit also specifies the volume of water the holder may use each year. In addition to managing surface water rights, the agency enforces laws by the federal government meant to keep water quality safe enough to drink and protect ecosystems. Agency staff also respond to any contamination events that could threaten the state’s water supply. The TCEQ is different from the Texas Water Development Board, which serves as a bank that funds water projects and is responsible for long-term water supply planning. How does the state gauge how much groundwater is available? The Texas Legislature passed in 1949 the Texas Groundwater Act, which authorized the formation of groundwater districts, but it wasn’t until close to 50 years later that the state explicitly recognized groundwater districts as the state’s preferred method for managing groundwater resources in Texas. Today, 98 Texas groundwater districts cover nearly 70% of the state’s land area. These districts implement various management strategies, including developing and enforcing rules and balancing property rights with preservation goals. A key aspect of this is using groundwater modeling, monitoring wells and data to make decisions about groundwater quantity and quality. Each groundwater district sets goals that describe how much water can be pumped without depleting aquifers for future generations. These “desired future conditions” are key for understanding and managing groundwater availability long-term. To set such goals, districts monitor wells and get water level measurements to track changes and trends in aquifers, a body of rock or sediment underground that holds groundwater. Districts also model how much water they anticipate will get extracted across certain periods. This data and predictions are submitted to a regional groundwater management area and are run through groundwater availability models to project aquifer conditions if these extractions occur as planned. The districts then review model results and set their goals. The Texas Water Development Board independently reviews the models to ensure the projected extractions are feasible and will achieve the goals as well. The water board then calculates the amount of water that can be pumped annually while staying within the goals set by the districts. How will reservoirs be affected by climate change? Climate change will have a significant impact on reservoirs in Texas, and it could get ugly fast. One report studied the effect climate change has on water quality in Texas reservoirs. The researchers expect the weather pattern shifts will lead to increased water temperatures, sulfate and chloride. At the same time, it will cause decreasing levels of oxygen and pH, meaning water in reservoirs could become more acidic. Not only would this combination affect the ecosystems in the reservoirs, but it will affect the quality of water for Texans, both for consumption and recreation. A 2022 Texas Tribune analysis found that the hotter Texas gets, water levels in the reservoirs will also drop. That year, which holds the record for the hottest July recorded, led to a devastating drought and pushed municipalities to call for mandatory water restrictions. It’s a domino effect — higher temperatures cause soil to dry more quickly, which then causes less rain to flow into Texas’ rivers and streams. The longer and more intense hot temperatures continue, climate change also accelerates water evaporation from Texas’ reservoirs. Since surface water, which is mainly stored in Texas’ rivers and reservoirs, accounts for about half of the state’s water supply, climate change makes it less and less reliable. Which region or city has the highest quality of water supply? Water quality varies throughout the state. However, a 2024 statewide competition crowned Dallas for having the best drinking water in Texas. There were 23 water providers in the competition who provided unlabeled water samples for the judges, and it was judged by the taste and smell of the water. The runner-up was Denton, so by this competition alone, it could be North Texas that has the highest quality of water. That’s not to say water in the region doesn’t have problems. According to the North Texas Municipal Water District, taste, odor and hard water can still occur from naturally occurring minerals present in the lakes across the region. They are one of many water districts in the region that has rigorous monitoring of water conditions and test samples on a regular basis to ensure water meets or exceeds standards set by the Texas Commission on Environmental Quality, the U.S. Environmental Protection Agency, and the Safe Drinking Water Act.

You asked our AI chatbot about Texas’ water supply. We answered some of the questions that it couldn’t.

Subscribe to The Y’all — a weekly dispatch about the people, places and policies defining Texas, produced by Texas Tribune journalists living in communities across the state.


Audio recording is automated for accessibility. Humans wrote and edited the story. See our AI policy, and give us feedback.

For most of this year, Texas Tribune reporters have aggressively reported on the state’s water supply crisis. As part of our special report, Running Out, we created a chatbot that we trained to answer your questions based on our reporting.

Y’all asked a lot of questions! And in some instances, the bot could not answer those questions. Technology! Can’t live with it, can’t live without it. Those queries were sent to us. We read each one and began saw some themes.

Many of you had specific questions about your own region. If you still do, you can use this tool to look up the water situation in your county. Many of you wanted to know when the state was going to run out of water, who is in charge, and how much we should worry about climate change.

We identified the six most commonly asked questions and answered them below.

Texas voters this week once again voted overwhelmingly to fund water projects for the next 20 years. As the Tribune reported, the money will help. And yet, the $20 billion sum falls far short of what might be needed. Our reporting on the state’s water supply and the looming crisis will not end, even as this year comes to a close. Keep the questions and story ideas coming.

Will Texas actually run out of water?

There are some scary estimates out there. The Texas Water Development Board projects in the state’s 2022 water plan that towns and cities could be on a path toward a severe shortage of water by 2030. This means everything, from drinking water to wastewater, and water for agricultural uses, could run low in the next few years.

However, there are several factors that go into that, including if there is a recurring, record-breaking drought across the state and if water entities and state leaders fail to put key strategies in place to secure water supplies. Those strategies range from creating new sources of water supply — think desalination, conservation, and aquifer storage and recovery — to fixing the failing infrastructure that causes water lines to break and gush water out all around the state.

Other estimates give us a little more time, but don’t look much better. The state water plan projects that groundwater availability, which is found underground in aquifers, makes up half of the state’s water supply, will drop by 25% by 2070. Our total water supply — groundwater paired with surface water — is estimated to decline by 18% by the same year, in part because of how many people are expected to live in Texas by then.

This is why advocates say the dedicated funding approved by voters this year was so critical. That money goes toward repairing aging infrastructure and projects that create the new sources of water supply that the future of the state will rely on.

What are the most affected regions in Texas by water shortages and why?

Texas has 16 regions for water planning. Each faces unique challenges and are tasked with managing their own water supply.

Generally, East Texas is more lush and water-rich, while West Texas is much dried. South Texas, especially the Rio Grande Valley, has been plagued by an ongoing drought. A binational tussle over water with Mexico, also isn’t helping the region. All of Texas water supply is impacted by a combination of the following: limited supplies, population growth, and climate pressures.

In their planning, regional leaders are supposed to project their water supply and water demand for the following years to come.

Since water supply varies by region, the Texas Tribune created an address-search tool based on that data. This tool shows where your local water supply comes from and what supply and demand projections look like for the future. You can find it here.

What role does the Texas Commission on Environmental Quality play in protecting the state’s water supply?

Surface water — the stuff in lakes and rivers — in Texas is owned by the state. The TCEQ, the state’s environmental regulator, oversees those rights. Since 1967, the TCEQ has issued permits granting farmers, ranchers, cities, industries, and businesses the right to use it. These permits are issued on a “first come, first served” basis, with each one assigned a priority date that determines seniority. During droughts, permit holders with the earliest dates have the right to get water before those with newer dates. Each permit also specifies the volume of water the holder may use each year.

In addition to managing surface water rights, the agency enforces laws by the federal government meant to keep water quality safe enough to drink and protect ecosystems. Agency staff also respond to any contamination events that could threaten the state’s water supply.

The TCEQ is different from the Texas Water Development Board, which serves as a bank that funds water projects and is responsible for long-term water supply planning.

How does the state gauge how much groundwater is available?

The Texas Legislature passed in 1949 the Texas Groundwater Act, which authorized the formation of groundwater districts, but it wasn’t until close to 50 years later that the state explicitly recognized groundwater districts as the state’s preferred method for managing groundwater resources in Texas. Today, 98 Texas groundwater districts cover nearly 70% of the state’s land area.

These districts implement various management strategies, including developing and enforcing rules and balancing property rights with preservation goals. A key aspect of this is using groundwater modeling, monitoring wells and data to make decisions about groundwater quantity and quality.

Each groundwater district sets goals that describe how much water can be pumped without depleting aquifers for future generations. These “desired future conditions” are key for understanding and managing groundwater availability long-term. To set such goals, districts monitor wells and get water level measurements to track changes and trends in aquifers, a body of rock or sediment underground that holds groundwater. Districts also model how much water they anticipate will get extracted across certain periods. This data and predictions are submitted to a regional groundwater management area and are run through groundwater availability models to project aquifer conditions if these extractions occur as planned. The districts then review model results and set their goals. The Texas Water Development Board independently reviews the models to ensure the projected extractions are feasible and will achieve the goals as well. The water board then calculates the amount of water that can be pumped annually while staying within the goals set by the districts.

How will reservoirs be affected by climate change?

Climate change will have a significant impact on reservoirs in Texas, and it could get ugly fast. One report studied the effect climate change has on water quality in Texas reservoirs. The researchers expect the weather pattern shifts will lead to increased water temperatures, sulfate and chloride. At the same time, it will cause decreasing levels of oxygen and pH, meaning water in reservoirs could become more acidic. Not only would this combination affect the ecosystems in the reservoirs, but it will affect the quality of water for Texans, both for consumption and recreation.

A 2022 Texas Tribune analysis found that the hotter Texas gets, water levels in the reservoirs will also drop. That year, which holds the record for the hottest July recorded, led to a devastating drought and pushed municipalities to call for mandatory water restrictions. It’s a domino effect — higher temperatures cause soil to dry more quickly, which then causes less rain to flow into Texas’ rivers and streams. The longer and more intense hot temperatures continue, climate change also accelerates water evaporation from Texas’ reservoirs.

Since surface water, which is mainly stored in Texas’ rivers and reservoirs, accounts for about half of the state’s water supply, climate change makes it less and less reliable.

Which region or city has the highest quality of water supply?

Water quality varies throughout the state. However, a 2024 statewide competition crowned Dallas for having the best drinking water in Texas. There were 23 water providers in the competition who provided unlabeled water samples for the judges, and it was judged by the taste and smell of the water. The runner-up was Denton, so by this competition alone, it could be North Texas that has the highest quality of water.

That’s not to say water in the region doesn’t have problems. According to the North Texas Municipal Water District, taste, odor and hard water can still occur from naturally occurring minerals present in the lakes across the region. They are one of many water districts in the region that has rigorous monitoring of water conditions and test samples on a regular basis to ensure water meets or exceeds standards set by the Texas Commission on Environmental Quality, the U.S. Environmental Protection Agency, and the Safe Drinking Water Act.

Read the full story here.
Photos courtesy of

Cruz, Cornyn push new retaliatory legislation that blocks U.S. water from going to Mexico

The bill is the latest effort from the Texas delegation that demands the U.S. get tougher with Mexico for failing to honor a 1944 treaty that in part governs Rio Grande water.

Subscribe to The Y’all — a weekly dispatch about the people, places and policies defining Texas, produced by Texas Tribune journalists living in communities across the state. Audio recording is automated for accessibility. Humans wrote and edited the story. See our AI policy, and give us feedback. McALLEN — U.S. Sens. Ted Cruz and John Cornyn want to limit the U.S.’s engagement with Mexico after the country failed to deliver water to Texas under a 1944 international water treaty. The Texas senators filed legislation Thursday that would limit the U.S. from sending Mexico future deliveries of water and would allow the U.S. president to stop engaging with Mexico in certain business sectors that benefit from U.S. water. The treaty requires the U.S. to deliver 1,500,000 acre-feet of water from the Colorado River to Mexico every year. In exchange, Mexico is required to deliver 1,750,000 acre-feet of water to the U.S. every five years, or 350,000 acre-feet per year, from six tributaries. The delay in water continues to frustrate local farmers and ranchers who depend on water for their irrigation needs. Water received from Mexico is typically stored at two international reservoirs. When water is released, it feeds into the Rio Grande. However, combined levels at the reservoirs reached a record low last year and continue to be in limited supply due, in part, to lack of rainfall. When reservoir water is in short supply, irrigation water for farmers is the first to be cut off. This has had a devastating impact on the Rio Grande Valley’s agricultural community, prompting the shutdown of Texas’ last sugar mill in Santa Rosa, though investors announced they plan to revive it. “The Mexican government exploits the structure of the treaty to defer and delay its deliveries in each individual year until it becomes impossible for it to meet its overall obligations, and it continues to fail to meet its obligation to deliver water to the United States under the 1944 Water Treaty,” Cruz said in a statement. “These failures are catastrophic for Texas farmers and ranchers, who rely on regular and complete deliveries by Mexico under the treaty and are on the front lines of this crisis, facing water shortages that threaten agriculture and livestock.” Mexico has struggled to meet its obligations. When the most recent five-year cycle came to an end on Oct. 24, Mexico still owed 865,136 acre-feet of water. Because of drought conditions, Mexico has the next five years to pay back its debt. The bill would try to compel Mexico to make minimum annual deliveries instead of allowing Mexico to pay what it owes at the end of the five years. It also requires the U.S. secretary of state to submit a report to Congress on the status of Mexico’s water deliveries within 180 days of the bill’s enactment. The report would determine whether Mexico had delivered at least 350,000 acre-feet of water the previous year. The report would also assess whether Mexico is capable of delivering the full 1,750,000 acre-feet of water by the end of the five-year cycle, and would identify economic sectors and activities in Mexico that benefit from the water it receives from the U.S. and from water from the six tributaries managed by the treaty. If Mexico fails to deliver at least 350,000 acre-feet in the previous year, the bill would require the president to deny all emergency requests from Mexico for the delivery of water under any amendments to the treaty. However, exceptions would be made if the water were used exclusively for an ongoing ecological, environmental, or humanitarian emergency or if fulfilling the request is vital to U.S. national interests. The president may also limit or terminate engagement with Mexico related to those sectors or activities that benefit from the water it gets from the U.S. or from the six tributaries. Exceptions would be made for engagement that relates to countering the flow of fentanyl and other synthetic drugs. Hoping to enact consequences for failing to comply with the water treaty, the Valley’s congressional delegation — including U.S. Reps. Monica De La Cruz, a Republican from Edinburg, Henry Cuellar, a Laredo Democrat, and Cornyn — said they favored including the water treaty in trade talks next year when the U.S.-Mexico-Canada agreement is up for review. “Mexico has repeatedly failed to uphold the 1944 Water Treaty, including last month when they missed the five-year deadline to deliver the 1.75 million acre-feet of water owed to the United States,” Cornyn said. “I am proud to cosponsor this legislation alongside Senator Cruz, which will put added pressure on Mexico to live up to its obligations under the Treaty, ensure the South Texas agriculture community has the water it needs, and impose harsher penalties on Mexico should they choose to continue withholding the water we’re owed.” The bill could potentially work faster to add an enforcement mechanism to the treaty if it is passed. “Without stronger congressional pressure and oversight, Mexico will continue to fail to meet its obligations,” Cruz said. Reporting in the Rio Grande Valley is supported in part by the Methodist Healthcare Ministries of South Texas, Inc.

Texas set to make $20 billion investment in water after voters approve Proposition 4

Texas will use $1 billion in sales tax a year for the next two decades to help secure the state’s water supply.

Subscribe to The Y’all — a weekly dispatch about the people, places and policies defining Texas, produced by Texas Tribune journalists living in communities across the state. Audio recording is automated for accessibility. Humans wrote and edited the story. See our AI policy, and give us feedback. Texas is poised to make the largest investment in its water supply in the state’s 180-year history as voters on Tuesday are on track to approve Proposition 4, which authorizes $20 billion to be spent on water projects over the next two decades.  The vote comes at a time when communities are scrambling to find new water supplies to meet the needs of their growing population, all the while deteriorating infrastructure, and a warming climate threatens the state’s water supply.   Throughout Texas’ history, ensuring water supply has rarely been a partisan issue. Many see it as a precious resource essential to both survival and the prosperity of the state’s economy. However, this year proved that water is personal and deeply emotional too. Proposed reservoirs and groundwater exports in East Texas have outraged many in the water-rich region, desalination projects along the Coastal Bend region have sparked political debate amid a water crisis, and data centers expanding across arid West Texas have locals worried about their dwindling groundwater supply. These challenges and others pushed lawmakers to make big investments in water at the Capitol this year. “Prop 4 is the culmination of almost 30 years of bipartisan work to create reliable and predictable funding for Texas water,” said Sarah Rountree Schlessinger, CEO of Texas Water Foundation, a nonprofit that educates Texans on water issues.  “We are thrilled that Texans showed up, asked deep questions, and that they chose to prioritize water infrastructure needs across the state. That tells you a lot about the state of Texas water.” A portion of existing state sales tax revenue — up to $1 billion annually — would be deposited into the Texas Water Fund each year, starting in 2027 to help fund water, wastewater and flood infrastructure projects.  The funding comes from existing revenue, meaning no new taxes would be created. However, the money would only be transferred to the fund when sales tax collections exceed $46.5 billion in a given year. The past two fiscal years have surpassed that amount. Assuming the state’s growth continues, there will be enough money available to dedicate the $1 billion to the fund.  The $20 billion is far short of what the state needs to maintain its water infrastructure. According to one estimate, Texas communities need nearly $154 billion over the next 50 years for projects. Both rural and urban communities will be able to tap the fund to address their existing infrastructure needs. The money will be managed by the Texas Water Development Board, the state agency that oversees the state’s water supply. Funding would be divided into two categories: water supply projects, and other existing water programs.  Water supply projects would expand the overall volume of water available in Texas. Projects that could be paid for include desalination, which cleans salty water for drinking and agricultural use, fixing leaking pipes, water reuse, which includes treating wastewater and  produced water from the oil and gas industry, conservation strategies and constructing permitted reservoirs. Existing water programs include improving flood control infrastructure and flood mitigation, ensuring clean drinking water, and agricultural water conservation.  While oil and gas, and big statewide water groups in Texas supported the proposition, some environmental groups were concerned that certain projects, like reservoirs, will be prioritized as a form of new water supply and take the land of farmers and residents who live in areas where they plan to be built.  Other organizations feared it will help fund mega projects like desalination, which they believe will help industry expansion in their communities, and that local communities will be cut out of water decisions. Some conservative groups argued that spending should not be written into the Texas Constitution.   The proposition does not greenlight projects, but rather provides a way to finance projects. Any particular project that receives funds from the Water Development Board will go through a regular application process. The Texas Water Foundation said that the proposition prohibits the transfer of groundwater. The fund also comes with some oversight. Lawmakers have created a special committee to oversee the water board’s administration of the funding. The water board will be required to report on how the money is being distributed and the impact they are having in meeting state needs and the public will have a chance to give input.  Disclosure: Texas Water Foundation has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune’s journalism. Find a complete list of them here.

Ofwat letting water firms charge twice to tackle sewage, court to hear

River Action bringing legal action against water regulator over who should foot bill for firms’ past failures to investOfwat is unlawfully allowing water companies to charge customers twice to fund more than £100bn of investment to reduce sewage pollution, campaigners will allege in court on Tuesday.Lawyers for River Action say the bill increases being allowed by Ofwat – which amount to an average of £123 a year per household – mean customers will be paying again for improvements to achieve environmental compliance that should have been funded from their previous bills. Continue reading...

Ofwat is unlawfully allowing water companies to charge customers twice to fund more than £100bn of investment to reduce sewage pollution, campaigners will allege in court on Tuesday.Lawyers for River Action say the bill increases being allowed by Ofwat – which amount to an average of £123 a year per household – mean customers will be paying again for improvements to achieve environmental compliance that should have been funded from their previous bills.Ofwat has approved a £104bn injection of cash by water companies to the end of the decade, in what is referred to as its PR24 decision, to tackle record sewage pollution into rivers as a result of underinvestment over many years.Customers of some of the worst-performing companies are facing huge bill rises. Thames Water customers are being charged 35% more, raising average bills from £436 to £588, and Southern Water customers are being charged 53% more, increasing from £420 to £642 a year on average. United Utilities is raising bills by 32% to an average of £535 a year.Lawyers are using the case of Windermere as an example to argue that customers are being unlawfully charged twice. They argue that any investment to repair historic under-investment in infrastructure should be paid for by shareholders, not customers. According to Ofwat rules, customers must only pay for new infrastructure investment, not investment to bring a company into compliance with environmental legislation.Emma Dearnaley, the head of legal at River Action, said: “It is fundamental that the public should not be made to pay twice for water companies’ past failures to invest in improvements to stop sewage pollution. But River Action is concerned that Ofwat’s approach means customers could be paying again. Meanwhile, degraded infrastructure keeps spewing pollution into rivers and lakes across the country that should have been clean decades ago.”The case argues that Ofwat must ensure the billions it approves results in legal compliance by water companies and that customers are charged fairly from now on.Ricardo Gama, of Leigh Day, who is representing River Action at the hearing in Manchester, said: “Our client believes that this case shows that Ofwat has failed to make sure that water bills are used for infrastructure upgrades.“River Action will argue that the money that could and should have been used to make essential infrastructure improvements is now gone, and customers are being asked to foot the bill for those improvements a second time over.”The hearing takes place at Manchester civil justice centre on Tuesday and Wednesday.An Ofwat spokesperson said: “We reject River Action’s claims. The PR24 process carefully scrutinised business plans to ensure that customers were getting fair value and investment was justified.“We stated that customers should not pay twice for companies to regain compliance with environmental permits, and have included appropriate safeguards in our PR24 determinations to monitor this, which we will monitor closely, taking action if required. We cannot comment further at this time due to the ongoing hearing.”

Scientists Hope Underwater Fiber-Optic Cables Can Help Save Endangered Orcas

Scientists from the University of Washington recently deployed a little over 1 mile of fiber-optic cable in the Salish Sea to test whether internet cables can monitor endangered orcas

SAN JUAN ISLAND, Wash. (AP) — As dawn broke over San Juan Island, a team of scientists stood on the deck of a barge and unspooled over a mile of fiber-optic cable into the frigid waters of the Salish Sea. Working by headlamp, they fed the line from the rocky shore down to the seafloor — home to the region's orcas.The bet is that the same hair-thin strands that carry internet signals can be transformed into a continuous underwater microphone to capture the clicks, calls and whistles of passing whales — information that could reveal how they respond to ship traffic, food scarcity and climate change. If the experiment works, the thousands of miles of fiber-optic cables that already crisscross the ocean floor could be turned into a vast listening network that could inform conservation efforts worldwide.The technology, called Distributed Acoustic Sensing, or DAS, was developed to monitor pipelines and detect infrastructure problems. Now University of Washington scientists are adapting it to listen to the ocean. Unlike traditional hydrophones that listen from a single spot, DAS turns the entire cable into a sensor, allowing it to pinpoint the exact location of an animal and determine the direction it’s heading.“We can imagine that we have thousands of hydrophones along the cable recording data continuously,” said Shima Abadi, professor at the University of Washington Bothell School of STEM and the University of Washington School of Oceanography. “We can know where the animals are and learn about their migration patterns much better than hydrophones.”The researchers have already proven the technology works with large baleen whales. In a test off the Oregon coast, they recorded the low-frequency rumblings of fin whales and blue whales using existing telecommunications cables.But orcas present a bigger challenge: Their clicks and calls operate at high frequencies at which the technology hasn’t yet been tested.The stakes are high. The Southern Resident orcas that frequent the Salish Sea are endangered, with a population hovering around 75. The whales face a triple threat: underwater noise pollution, toxic contaminants and food scarcity.“We have an endangered killer whale trying to eat an endangered salmon species,” said Scott Veirs, president of Beam Reach Marine Science and Sustainability, an organization that develops open-source acoustic systems for whale conservation.The Chinook salmon that orcas depend on have declined dramatically. Since the Pacific Salmon Commission began tracking numbers in 1984, populations have dropped 60% due to habitat loss, overfishing, dams and climate change.Orcas use echolocation – rapid clicks that bounce off objects – to find salmon in murky water. Ship noise can mask those clicks, making it difficult for them to hunt.If DAS works as hoped, it could give conservationists real-time information to protect the whales. For instance, if the system detects orcas heading south toward Seattle and calculates their travel speed, scientists could alert Washington State Ferries to postpone noisy activities or to slow down until the whales pass.“It will for sure help with dynamic management and long-term policy that will have real benefits for the whales,” Veirs said.The technology would also answer basic questions about orca behavior that have eluded scientists, such as determining whether their communication changes when they’re in different behavioral states and how they hunt together. It could even enable researchers to identify which sound is coming from a particular whale — a kind of voice recognition for orcas.The implications extend far beyond the Salish Sea. With some 870,000 miles (1.4 million kilometers) of fiber-optic cables already installed underwater globally, the infrastructure for ocean monitoring largely exists. It just needs to be tapped. “One of the most important challenges for managing wildlife, conserving biodiversity and combating climate change is that there’s just a lack of data overall,” said Yuta Masuda, director of science at Allen Family Philanthropies, which helped fund the project.The timing is critical. The High Seas Treaty enters into force in January, which will allow for new marine protected areas in international waters. But scientists still don’t understand how human activities affect most ocean species or where protections are most needed. A dataset as vast as the one the global web of submarine cables could provide might help determine which areas should be prioritized for protection.“We think this has a lot of promise to fill in those key data gaps,” Masuda said.Back on the barge, the team faced a delicate task: fusing two fibers together above the rolling swell. They struggled to align the strands in a fusion splicer, a device that precisely positions the fiber ends before melting them together with an electric current. The boat rocked. They steadied their hands and tried again, and again. Finally, the weld held. Data soon began flowing to a computer on shore, appearing as waterfall plots — cascading visualizations that show sound frequencies over time. Nearby, cameras trained on the water stood ready so that if a vocalization was detected, researchers could link a behavior with a specific call.All that was left was to sit and wait for orcas.The Associated Press receives support from the Walton Family Foundation for coverage of water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/climate-and-environmentCopyright 2025 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.Photos You Should See – Oct. 2025

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