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A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs

News Feed
Tuesday, September 10, 2024

Germany’s North and Baltic Seas are littered with munitions from the First and Second World Wars, such as shells—as shown here—once fired from German battleships. SeaTerra Aboard the Alkor, a 180-foot oceanographic vessel anchored in the Baltic Sea a few miles from the German port city of Kiel, engineer Henrik Schönheit grips a joystick-like lever in his fist. He nudges the lever up, and a one-of-a-kind robotic sea crawler about the size of a two-seat golf cart responds, creeping forward along the seafloor on rubber caterpillar tracks 40 feet below the ship. As the crawler inspects Kiel Bay’s sandy terrain, a live video stream beams up to a computer screen in a cramped room aboard the ship. The picture is so crystalline that it’s possible to count the tentacles of a translucent jellyfish floating past the camera. A scrum of scientists and technicians ooh and aah as they huddle around the screen, peering over Schönheit’s shoulder. The bright-yellow robot is the Norppa 300, the newest fabrication of the explosive ordnance disposal company SeaTerra, which operates out of northern Germany. SeaTerra’s co-founder Dieter Guldin rates as one of Europe’s canniest experts on salvaging sunken explosives. Now, after years of experience clearing the seafloor of hazards for commercial operations, and campaigning the German government for large-scale remediation, SeaTerra is one of three companies participating in the first-ever mission to systematically clear munitions off a seafloor in the name of environmental protection. The arduous and exacting process of removing and destroying more than 1.6 million tons of volatile munitions from the Baltic and North Sea basins—an area roughly the size of West Virginia—is more urgent by the day: The weapons, which have killed hundreds of people who have come into accidental contact with them in the past, are now corroded. Their casings are breaking apart and releasing carcinogens into the seas. Onboard the Alkor, during a test run this May, SeaTerra technicians Klaus-Dieter Golla, left, and Henrik Schönheit discuss video footage of the seafloor transmitted by the company’s Norppa 300 robot. Andreas Muenchbach SeaTerra’s top technicians aboard the Alkor are testing the Norppa 300’s basic functions in the wild prior to the project’s start this month, in early September 2024: ensuring that its steering, sonar imaging of the seafloor, chemical sampler and video feed are fine-tuned. Everyone huddled in the ship’s dry lab watches rapt as the crawler bumps up against a vaguely rectangular object the size of a bar fridge. It’s largely obscured by seaweed and, from the looks of it, home to a lone Baltic flounder that’s swimming around the base. Aaron Beck, senior scientist at the Geomar Helmholtz Center for Ocean Research, a German marine research institute working alongside SeaTerra, identifies it as an ammunition crate. “Look, the flatness there, the corner. That’s not of the natural world,” he exclaims. Dumped munitions lie in waters around the world but are ubiquitous in German waters. In the aftermath of World War II, all the conflict parties, including the United Kingdom, Russia, Japan and the United States, had to divest themselves of armaments. “They didn’t want [them] on land, and facilities to destroy [them] were too few,” explains Anita Künitzer of the German Environment Agency. Dumping at sea, a practice held over from World War I, was the obvious choice. In occupied Germany, British forces established underwater disposal zones—one of which lies near Kiel Bay. “But,” says Guldin, “on their way to the designated dumping grounds, they also just threw hardware overboard.” Grainy black-and-white film footage shows British sailors busily operating multiple conveyor belts to cast crate after crate of leftovers into the sea. Whole ships and submarines packed with live munitions were scuttled in the rush to disarm the Germans. 1500 Miles Of Bombs Along Our Roads Aka Ammunition Dumps Or Arms Dump (1946) Experts estimate that a ginormous 1.8 million tons of conventional munitions and another 5,500 tons of chemical weapons lie decomposing off Germany alone in the North and Baltic Seas, most from World War II. (Because of its busy ports, the North Sea received four times as much as the Baltic.) If all that weaponry were lined up, it would stretch from Paris to Moscow, about 1,500 miles! “Nowhere in German waters is there a square kilometer of seabed without munitions,” says Guldin. In the postwar decades, freelancing scrap metal collectors hauled explosives and other valuable wartime debris ashore to hawk on the metals market. Fisher boats that ensnared unexploded munitions in their nets were required to turn them in to coastal authorities, not toss them overboard again. The German Navy’s anti-mine units attempted to clear some of the mess, usually through initiating underwater explosions, but lacked the proper equipment to tackle the problem systematically. Only when the private sector picked up operations did a whole new suite of technology and skill sets emerge. Since the late 2000s, SeaTerra’s ensemble of marine biologists, hydraulic specialists, sedimentologists, divers, engineers, geophysicists, marine surveyors, pyrotechnicians and archaeologists—now about 160 people—have been mapping the sunken armaments as they worked to clear safe patches of seafloor for wind-farm, cable and pipeline projects. But until this year, SeaTerra never possessed the remit it has long coveted: to begin systematically ameliorating the seafloor for the sake of marine ecosystems—and the people dependent on them. The German government has set aside 100 million euros (over $110 million) to remove the toxic mess from Lübeck Bay, off the Baltic port city of Lübeck, southeast of Kiel, as a pilot project. “No other country in the world has ever attempted or achieved this,” says Tobias Goldschmidt, the region’s environment minister, in a press release. Experts prepare the Norppa 300 for a trial run in the Baltic Sea in May. Andreas Muenchbach Guldin and other advocates are elated that the project is on, but they acknowledge it will only dent the Baltic’s total quantity of submerged ordnance. Their goal is to recover between 55 and 88 tons worth of munitions, though the pilot’s primary purpose is for SeaTerra and the two other firms to test their technology and to demonstrate to bankrollers that the job is doable. “Then it’s about scaling up and getting faster,” says Guldin. Faster is vital, because in their watery graves, the many land and naval mines, U-boat torpedoes, depth charges, artillery shells, chemical weapons, aerial bombs, and incendiary devices have corroded over almost 80 years. The Germans, like other dumping nations, long assumed that when the casings broke down, the vast ocean would simply dissolve pollutants into harmless fractions. About 25 years ago, scientists discovered that instead, the explosives remain live and are now oozing into the ecosystem and up the food chain. That flounder darting in front of the crawler’s camera from the Alkor’s dry lab? It almost certainly contains traces of TNT, the highly toxic compound used in explosives. Toxicologist Jennifer Strehse, from the Kiel-based Institute of Toxicology and Pharmacology for Natural Scientists, which identified the mounting toxic pollution, says that contamination is particularly widespread in shellfish, bottom-dwelling flatfish and other fauna that are close to the munition dumps. They’re “contaminated with carcinogens from TNT or arsenic or heavy metals like lead and mercury,” she says. An image of Lübeck bay’s seafloor shows a smattering of bombs. Geomar Helmholtz Centre for Ocean Research Scientists have also found toxic concentrations of TNT in Atlantic purple sea urchins, mysid crustaceans and blue mussels. Once contaminants have escaped into the water, they can’t be recovered, Strehse points out. “So, we’re working against time.” German health experts recommend that consumers limit themselves to no more than two meals of local fish a week to reduce exposure to heavy metals, dioxins or PCBs. The source of most of these contaminants are industrial processes and the burning of fossil fuels; TNT does not figure into the guidelines. Nevertheless, the risk of TNT and other contaminants from weapons is enough to cause Strehse, herself, to steer clear of all Baltic Sea mussels. The risk of immediate loss of life is also ever-present. Most of the submerged weapons remain as powerful as the day they were dumped. Now rusted through, they are even more unstable—presenting a precarious obstacle to fishing boats trawling the seafloor as well as offshore wind-farm developers, whose sprawling turbine parks are integral to Europe’s transition to clean energy systems. In the two German seas, over 400 people—tourists, sailors, fishers, naval cadets and munitions experts—have lost their lives to explosions from sunken weapons. German aerial bombs retrieved from the Baltic Sea are stacked and secured before the SeaTerra team transports them ashore for disposal. Germany currently has only one major disposal facility for unexploded ordnance. SeaTerra The menace doesn’t stay at sea, either. As the munitions deteriorate, amber-colored chunks of phosphorous from incendiary bombs, fragments of TNT or rusted casings often wash up on shore. Beachcombers who touch solid white phosphorus—usually mistaking it for Baltic amber, a sought-after gemstone—can suffer third-degree burns or worse. The chemical element sticks to human skin and can combust spontaneously when exposed to air at temperatures above 86 degrees Fahrenheit. Over half a century after the fighting ended, the task of addressing the environmental danger and risk to life from dumped munitions has become its own battle. When Guldin entered the field of munitions cleanup in 2000, he saw the problem’s vastness and malevolent power as the ultimate challenge for his technical imagination. Fifty-seven-year-old Guldin describes himself as a pacifist by nature and archaeologist by training. He grew up far removed from oceans, in southern Germany’s Black Forest where, as a conscientious objector, he refused to serve in the German Army, later joining the Green Party instead. He helped excavate Roman settlements along the Rhine River. Then he moved on to the Middle East, where he unearthed ancient civilizations in Yemen and Lebanon. Eventually, in 2000, he admitted to himself that the long stays abroad and one-off digs weren’t conducive to the family life he wanted. Shortly after this, he touched base with an old friend, Edgar Schwab. Dieter Guldin of SeaTerra has been encouraging the German government to clean up sunken war munitions for years. Drones Magazin Schwab, a geophysicist, was in Hamburg, Germany, and one step ahead of his buddy—starting up a little company to appropriate the lethal relics of the Third Reich from the ocean floor. The two friends were less interested in digging to explain humanity’s past than in undoing the damage it had inflicted upon nature, and together they co-founded SeaTerra. Guldin immersed himself in the history of munitions dumping in Northern Europe—a practice that was discontinued worldwide only in 1975. While SeaTerra conscientiously cleared patches of seafloor for industry, the mass of munitions across the greater seafloor gnawed at him. He insisted that his country clean it up so that future generations wouldn’t suffer this legacy of wars executed by generations past. He worked the halls of power for ten years but couldn’t get officialdom to touch the odious issue. The fact that the seafloor was littered with munitions has been common knowledge since 1945, but no one knew exactly how much there was or where. SeaTerra and a smorgasbord of concerned groups, including Strehse’s institute, understood that before anybody was going to address the issue, they first had to find out exactly what they were dealing with. In the course of its work for private companies, SeaTerra began developing technology—such as a prototype crawler, the DeepC—for surveying the seafloor, foot by excruciating foot. In the deep and churning North Sea, with its muscular tidal currents, much of the detritus lies yards beneath the seafloor. To penetrate the sediment, SeaTerra developed underwater drones and advanced multibeam radar equipment. For shallow tidal areas, SeaTerra also created low-flying drones outfitted with magnetic sensors that can detect metallic masses buried deep in the sand. SeaTerra technicians lower a device called a ScanFish. They use it to tow magnetic sensors through the water, about six feet above the seafloor. SeaTerra Many of SeaTerra’s innovations entailed modifying technology used in related fields, like mining, pyrotechnics and archaeology. The team started with a lot of energy but few resources: “In the beginning, we used zip ties and duct tape for everything,” Guldin says. The range of state-of-the-art technology the team now operates is not the brainchild of one person, but Guldin has been central to much of it. Now, with a firm grasp of the problem and how to address it, Guldin and others at SeaTerra are itching to display their accumulated know-how in Lübeck Bay. “The time has now come,” he announced recently on LinkedIn. “We, the explosive ordnance disposal companies, can now start our real work to make the oceans cleaner … and to measure our ideas and concepts against the physical reality of this blight.” It is, his announcement says, a great success for the company and a “recognition of our many years of effort in developing new technologies and concepts for explosive ordnance at sea.” Aboard the Alkor, the scientists believe their star, the Norppa 300, is ready for official deployment in Lübeck Bay. The crawler is the culmination of years of invention, testing and tweaking. Unlike previous undersea robots, it operates at depths up to almost 1,000 feet and can do so 24/7, even in turbulent waters. Its many functions will relieve professional divers of some of the cleanup expedition’s most perilous tasks. The robot is equipped with sonar and acoustic imaging for detecting and identifying buried munitions. Its detachable arms include a custom-designed vacuum that gingerly sucks up sediment from buried explosives and a pincer for lifting pieces of ammunition. The cleanup process for weapons that can be handled will involve three general steps using specialized ships. First, SeaTerra’s engineers and scientists on the Alkor—the survey vessel—will scan the site and classify the munitions. They will also take water samples for the Geomar Helmholtz Center to analyze on board, distinguishing conventional from chemical weaponry. Chemical weapons, which contain phosgene, arsenic and sulfur mustard (also known as mustard gas), are too lethal to handle, probably ever, admits Guldin. “You can’t see these gases or smell them,” he says, “and their detonation could blow a ship out of the water, killing a ship’s entire crew in a matter of minutes.” Those weapons will be left untouched. Aaron Beck of Geomar Helmholtz Center for Ocean Research stands beside a mass spectrometer, used to analyze the chemical contents of water samples, in the Alkor’s dry lab. Andreas Muenchbach Künitzer of the environment agency adds that the Nazis’ nerve gases were designed to incapacitate the eyes, skin and lungs of battlefield foes. “Decades underwater doesn’t dilute their potency,” she says. If the experts determine the material is safe enough for transportation, they’ll deploy the Norppa 300 to collect and deposit smaller items, like grenades, into undersea wire-mesh baskets. But if the explosive specialists monitoring from the ship above determine that the weaponry still contains detonators, divers—not a robot—will be sent to detach them. This is hazardous business that, thus far, only humans can execute. Next, a different team on a second ship—the clearance vessel—equipped with spud legs (stakes that hold the ship in place) will use a hydraulic crane equipped with cameras to extract larger munitions, including those with corrupted casings, and drop them into undersea receptacles. The final step is for a third team to haul the cargo onto the deck of their ship—the sorting vessel—to sort, label and package the lethal concoctions in steel tubes, and then transport them to an interim site in the Baltic Sea. There the material will be re-sunk in the tubes and stored underwater until it can be handed over to the responsible state authority, the Explosive Ordnance Disposal Service, for demolition. Some of the munitions SeaTerra clears from Germany’s seas date back to World War I, such as the six-inch-long cast iron shell shown here. SeaTerra The workers will have two months to clear the bay—and demonstrate whether the Norppa 300 and other technologies are either up to it or not. But there’s a hitch that will delay the destruction of all of the recovered weapons for about a year. Germany has a single major munitions disposal facility, and it is occupied with incinerating unexploded ordnance from around the globe, not least, incredibly, Nazi-era explosives still being unearthed from construction sites. That’s why the Lübeck Bay project’s budget includes construction of a disposal facility. The company and concept have yet to be finalized. One option is to build a floating clearance platform where robots would dissect ordnance and burn the chemical contents in a detonation chamber at temperatures of over 2300 degrees Fahrenheit, similar to how weapons are disposed of at the land-based facility. And there’s another issue. Over the years, the mounds of weaponry in the undersea dumping grounds have corroded and collapsed into one another, creating a gnarled, combustible mass of metals and explosive agents that make their recovery more complicated. The only options are to leave these or blow them up on-site. The best-case scenario is that all the Baltic’s most hazardous conventional munitions will finally be history by 2050, and work on the North Sea will be well underway. The worst case is that funding does not materialize and the mountains of explosives will continue to deteriorate en masse, emitting poisons. Before the green light came to start the cleanup, Guldin was becoming doubtful his country would ever address the mess, and he thought he might have to accept that SeaTerra’s expertise would never be put to the greater task that he and Schwab had envisioned. For the foreseeable future at least, he’ll be in the thick of culminating his life’s work, undoing some of humanity’s sins on the seafloor. This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com. Related stories from Hakai Magazine: • Weapons of War Litter the Ocean Floor • Why Ocean Shores Beachcombing Is a Blast Get the latest stories in your inbox every weekday.

The ocean became a dumping ground for weapons after Allied forces defeated the Nazis. Now a team of robots and divers is making the waters safer

header-uncropped-robots-and-war-munitions.jpg
Germany’s North and Baltic Seas are littered with munitions from the First and Second World Wars, such as shells—as shown here—once fired from German battleships. SeaTerra

Aboard the Alkor, a 180-foot oceanographic vessel anchored in the Baltic Sea a few miles from the German port city of Kiel, engineer Henrik Schönheit grips a joystick-like lever in his fist. He nudges the lever up, and a one-of-a-kind robotic sea crawler about the size of a two-seat golf cart responds, creeping forward along the seafloor on rubber caterpillar tracks 40 feet below the ship. As the crawler inspects Kiel Bay’s sandy terrain, a live video stream beams up to a computer screen in a cramped room aboard the ship. The picture is so crystalline that it’s possible to count the tentacles of a translucent jellyfish floating past the camera. A scrum of scientists and technicians ooh and aah as they huddle around the screen, peering over Schönheit’s shoulder.

The bright-yellow robot is the Norppa 300, the newest fabrication of the explosive ordnance disposal company SeaTerra, which operates out of northern Germany. SeaTerra’s co-founder Dieter Guldin rates as one of Europe’s canniest experts on salvaging sunken explosives. Now, after years of experience clearing the seafloor of hazards for commercial operations, and campaigning the German government for large-scale remediation, SeaTerra is one of three companies participating in the first-ever mission to systematically clear munitions off a seafloor in the name of environmental protection. The arduous and exacting process of removing and destroying more than 1.6 million tons of volatile munitions from the Baltic and North Sea basins—an area roughly the size of West Virginia—is more urgent by the day: The weapons, which have killed hundreds of people who have come into accidental contact with them in the past, are now corroded. Their casings are breaking apart and releasing carcinogens into the seas.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
Onboard the Alkor, during a test run this May, SeaTerra technicians Klaus-Dieter Golla, left, and Henrik Schönheit discuss video footage of the seafloor transmitted by the company’s Norppa 300 robot. Andreas Muenchbach

SeaTerra’s top technicians aboard the Alkor are testing the Norppa 300’s basic functions in the wild prior to the project’s start this month, in early September 2024: ensuring that its steering, sonar imaging of the seafloor, chemical sampler and video feed are fine-tuned. Everyone huddled in the ship’s dry lab watches rapt as the crawler bumps up against a vaguely rectangular object the size of a bar fridge. It’s largely obscured by seaweed and, from the looks of it, home to a lone Baltic flounder that’s swimming around the base. Aaron Beck, senior scientist at the Geomar Helmholtz Center for Ocean Research, a German marine research institute working alongside SeaTerra, identifies it as an ammunition crate. “Look, the flatness there, the corner. That’s not of the natural world,” he exclaims.


Dumped munitions lie in waters around the world but are ubiquitous in German waters. In the aftermath of World War II, all the conflict parties, including the United Kingdom, Russia, Japan and the United States, had to divest themselves of armaments. “They didn’t want [them] on land, and facilities to destroy [them] were too few,” explains Anita Künitzer of the German Environment Agency. Dumping at sea, a practice held over from World War I, was the obvious choice.

In occupied Germany, British forces established underwater disposal zones—one of which lies near Kiel Bay. “But,” says Guldin, “on their way to the designated dumping grounds, they also just threw hardware overboard.” Grainy black-and-white film footage shows British sailors busily operating multiple conveyor belts to cast crate after crate of leftovers into the sea. Whole ships and submarines packed with live munitions were scuttled in the rush to disarm the Germans.

1500 Miles Of Bombs Along Our Roads Aka Ammunition Dumps Or Arms Dump (1946)

Experts estimate that a ginormous 1.8 million tons of conventional munitions and another 5,500 tons of chemical weapons lie decomposing off Germany alone in the North and Baltic Seas, most from World War II. (Because of its busy ports, the North Sea received four times as much as the Baltic.) If all that weaponry were lined up, it would stretch from Paris to Moscow, about 1,500 miles! “Nowhere in German waters is there a square kilometer of seabed without munitions,” says Guldin.

In the postwar decades, freelancing scrap metal collectors hauled explosives and other valuable wartime debris ashore to hawk on the metals market. Fisher boats that ensnared unexploded munitions in their nets were required to turn them in to coastal authorities, not toss them overboard again. The German Navy’s anti-mine units attempted to clear some of the mess, usually through initiating underwater explosions, but lacked the proper equipment to tackle the problem systematically. Only when the private sector picked up operations did a whole new suite of technology and skill sets emerge.

Since the late 2000s, SeaTerra’s ensemble of marine biologists, hydraulic specialists, sedimentologists, divers, engineers, geophysicists, marine surveyors, pyrotechnicians and archaeologists—now about 160 people—have been mapping the sunken armaments as they worked to clear safe patches of seafloor for wind-farm, cable and pipeline projects.

But until this year, SeaTerra never possessed the remit it has long coveted: to begin systematically ameliorating the seafloor for the sake of marine ecosystems—and the people dependent on them. The German government has set aside 100 million euros (over $110 million) to remove the toxic mess from Lübeck Bay, off the Baltic port city of Lübeck, southeast of Kiel, as a pilot project. “No other country in the world has ever attempted or achieved this,” says Tobias Goldschmidt, the region’s environment minister, in a press release.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
Experts prepare the Norppa 300 for a trial run in the Baltic Sea in May. Andreas Muenchbach

Guldin and other advocates are elated that the project is on, but they acknowledge it will only dent the Baltic’s total quantity of submerged ordnance. Their goal is to recover between 55 and 88 tons worth of munitions, though the pilot’s primary purpose is for SeaTerra and the two other firms to test their technology and to demonstrate to bankrollers that the job is doable. “Then it’s about scaling up and getting faster,” says Guldin.


Faster is vital, because in their watery graves, the many land and naval mines, U-boat torpedoes, depth charges, artillery shells, chemical weapons, aerial bombs, and incendiary devices have corroded over almost 80 years. The Germans, like other dumping nations, long assumed that when the casings broke down, the vast ocean would simply dissolve pollutants into harmless fractions. About 25 years ago, scientists discovered that instead, the explosives remain live and are now oozing into the ecosystem and up the food chain.

That flounder darting in front of the crawler’s camera from the Alkor’s dry lab? It almost certainly contains traces of TNT, the highly toxic compound used in explosives. Toxicologist Jennifer Strehse, from the Kiel-based Institute of Toxicology and Pharmacology for Natural Scientists, which identified the mounting toxic pollution, says that contamination is particularly widespread in shellfish, bottom-dwelling flatfish and other fauna that are close to the munition dumps. They’re “contaminated with carcinogens from TNT or arsenic or heavy metals like lead and mercury,” she says.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
An image of Lübeck bay’s seafloor shows a smattering of bombs. Geomar Helmholtz Centre for Ocean Research

Scientists have also found toxic concentrations of TNT in Atlantic purple sea urchins, mysid crustaceans and blue mussels. Once contaminants have escaped into the water, they can’t be recovered, Strehse points out. “So, we’re working against time.”

German health experts recommend that consumers limit themselves to no more than two meals of local fish a week to reduce exposure to heavy metals, dioxins or PCBs. The source of most of these contaminants are industrial processes and the burning of fossil fuels; TNT does not figure into the guidelines. Nevertheless, the risk of TNT and other contaminants from weapons is enough to cause Strehse, herself, to steer clear of all Baltic Sea mussels.

The risk of immediate loss of life is also ever-present. Most of the submerged weapons remain as powerful as the day they were dumped. Now rusted through, they are even more unstable—presenting a precarious obstacle to fishing boats trawling the seafloor as well as offshore wind-farm developers, whose sprawling turbine parks are integral to Europe’s transition to clean energy systems. In the two German seas, over 400 people—tourists, sailors, fishers, naval cadets and munitions experts—have lost their lives to explosions from sunken weapons.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
German aerial bombs retrieved from the Baltic Sea are stacked and secured before the SeaTerra team transports them ashore for disposal. Germany currently has only one major disposal facility for unexploded ordnance. SeaTerra

The menace doesn’t stay at sea, either. As the munitions deteriorate, amber-colored chunks of phosphorous from incendiary bombs, fragments of TNT or rusted casings often wash up on shore. Beachcombers who touch solid white phosphorus—usually mistaking it for Baltic amber, a sought-after gemstone—can suffer third-degree burns or worse. The chemical element sticks to human skin and can combust spontaneously when exposed to air at temperatures above 86 degrees Fahrenheit.

Over half a century after the fighting ended, the task of addressing the environmental danger and risk to life from dumped munitions has become its own battle. When Guldin entered the field of munitions cleanup in 2000, he saw the problem’s vastness and malevolent power as the ultimate challenge for his technical imagination.


Fifty-seven-year-old Guldin describes himself as a pacifist by nature and archaeologist by training. He grew up far removed from oceans, in southern Germany’s Black Forest where, as a conscientious objector, he refused to serve in the German Army, later joining the Green Party instead. He helped excavate Roman settlements along the Rhine River. Then he moved on to the Middle East, where he unearthed ancient civilizations in Yemen and Lebanon. Eventually, in 2000, he admitted to himself that the long stays abroad and one-off digs weren’t conducive to the family life he wanted. Shortly after this, he touched base with an old friend, Edgar Schwab.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
Dieter Guldin of SeaTerra has been encouraging the German government to clean up sunken war munitions for years. Drones Magazin

Schwab, a geophysicist, was in Hamburg, Germany, and one step ahead of his buddy—starting up a little company to appropriate the lethal relics of the Third Reich from the ocean floor. The two friends were less interested in digging to explain humanity’s past than in undoing the damage it had inflicted upon nature, and together they co-founded SeaTerra.

Guldin immersed himself in the history of munitions dumping in Northern Europe—a practice that was discontinued worldwide only in 1975. While SeaTerra conscientiously cleared patches of seafloor for industry, the mass of munitions across the greater seafloor gnawed at him. He insisted that his country clean it up so that future generations wouldn’t suffer this legacy of wars executed by generations past. He worked the halls of power for ten years but couldn’t get officialdom to touch the odious issue.

The fact that the seafloor was littered with munitions has been common knowledge since 1945, but no one knew exactly how much there was or where. SeaTerra and a smorgasbord of concerned groups, including Strehse’s institute, understood that before anybody was going to address the issue, they first had to find out exactly what they were dealing with.

In the course of its work for private companies, SeaTerra began developing technology—such as a prototype crawler, the DeepC—for surveying the seafloor, foot by excruciating foot. In the deep and churning North Sea, with its muscular tidal currents, much of the detritus lies yards beneath the seafloor. To penetrate the sediment, SeaTerra developed underwater drones and advanced multibeam radar equipment. For shallow tidal areas, SeaTerra also created low-flying drones outfitted with magnetic sensors that can detect metallic masses buried deep in the sand.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
SeaTerra technicians lower a device called a ScanFish. They use it to tow magnetic sensors through the water, about six feet above the seafloor. SeaTerra

Many of SeaTerra’s innovations entailed modifying technology used in related fields, like mining, pyrotechnics and archaeology. The team started with a lot of energy but few resources: “In the beginning, we used zip ties and duct tape for everything,” Guldin says. The range of state-of-the-art technology the team now operates is not the brainchild of one person, but Guldin has been central to much of it.

Now, with a firm grasp of the problem and how to address it, Guldin and others at SeaTerra are itching to display their accumulated know-how in Lübeck Bay. “The time has now come,” he announced recently on LinkedIn. “We, the explosive ordnance disposal companies, can now start our real work to make the oceans cleaner … and to measure our ideas and concepts against the physical reality of this blight.” It is, his announcement says, a great success for the company and a “recognition of our many years of effort in developing new technologies and concepts for explosive ordnance at sea.”


Aboard the Alkor, the scientists believe their star, the Norppa 300, is ready for official deployment in Lübeck Bay. The crawler is the culmination of years of invention, testing and tweaking. Unlike previous undersea robots, it operates at depths up to almost 1,000 feet and can do so 24/7, even in turbulent waters. Its many functions will relieve professional divers of some of the cleanup expedition’s most perilous tasks. The robot is equipped with sonar and acoustic imaging for detecting and identifying buried munitions. Its detachable arms include a custom-designed vacuum that gingerly sucks up sediment from buried explosives and a pincer for lifting pieces of ammunition.

The cleanup process for weapons that can be handled will involve three general steps using specialized ships. First, SeaTerra’s engineers and scientists on the Alkor—the survey vesselwill scan the site and classify the munitions. They will also take water samples for the Geomar Helmholtz Center to analyze on board, distinguishing conventional from chemical weaponry. Chemical weapons, which contain phosgene, arsenic and sulfur mustard (also known as mustard gas), are too lethal to handle, probably ever, admits Guldin. “You can’t see these gases or smell them,” he says, “and their detonation could blow a ship out of the water, killing a ship’s entire crew in a matter of minutes.” Those weapons will be left untouched.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
Aaron Beck of Geomar Helmholtz Center for Ocean Research stands beside a mass spectrometer, used to analyze the chemical contents of water samples, in the Alkor’s dry lab. Andreas Muenchbach

Künitzer of the environment agency adds that the Nazis’ nerve gases were designed to incapacitate the eyes, skin and lungs of battlefield foes. “Decades underwater doesn’t dilute their potency,” she says.

If the experts determine the material is safe enough for transportation, they’ll deploy the Norppa 300 to collect and deposit smaller items, like grenades, into undersea wire-mesh baskets. But if the explosive specialists monitoring from the ship above determine that the weaponry still contains detonators, divers—not a robot—will be sent to detach them. This is hazardous business that, thus far, only humans can execute.

Next, a different team on a second ship—the clearance vessel—equipped with spud legs (stakes that hold the ship in place) will use a hydraulic crane equipped with cameras to extract larger munitions, including those with corrupted casings, and drop them into undersea receptacles. The final step is for a third team to haul the cargo onto the deck of their ship—the sorting vessel—to sort, label and package the lethal concoctions in steel tubes, and then transport them to an interim site in the Baltic Sea. There the material will be re-sunk in the tubes and stored underwater until it can be handed over to the responsible state authority, the Explosive Ordnance Disposal Service, for demolition.

A Massive Effort Is Underway to Rid the Baltic Sea of Sunken Bombs
Some of the munitions SeaTerra clears from Germany’s seas date back to World War I, such as the six-inch-long cast iron shell shown here. SeaTerra

The workers will have two months to clear the bay—and demonstrate whether the Norppa 300 and other technologies are either up to it or not.

But there’s a hitch that will delay the destruction of all of the recovered weapons for about a year. Germany has a single major munitions disposal facility, and it is occupied with incinerating unexploded ordnance from around the globe, not least, incredibly, Nazi-era explosives still being unearthed from construction sites. That’s why the Lübeck Bay project’s budget includes construction of a disposal facility. The company and concept have yet to be finalized. One option is to build a floating clearance platform where robots would dissect ordnance and burn the chemical contents in a detonation chamber at temperatures of over 2300 degrees Fahrenheit, similar to how weapons are disposed of at the land-based facility.

And there’s another issue. Over the years, the mounds of weaponry in the undersea dumping grounds have corroded and collapsed into one another, creating a gnarled, combustible mass of metals and explosive agents that make their recovery more complicated. The only options are to leave these or blow them up on-site. The best-case scenario is that all the Baltic’s most hazardous conventional munitions will finally be history by 2050, and work on the North Sea will be well underway. The worst case is that funding does not materialize and the mountains of explosives will continue to deteriorate en masse, emitting poisons.

Before the green light came to start the cleanup, Guldin was becoming doubtful his country would ever address the mess, and he thought he might have to accept that SeaTerra’s expertise would never be put to the greater task that he and Schwab had envisioned. For the foreseeable future at least, he’ll be in the thick of culminating his life’s work, undoing some of humanity’s sins on the seafloor.

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

Related stories from Hakai Magazine:

Weapons of War Litter the Ocean Floor

Why Ocean Shores Beachcombing Is a Blast

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Toxic Pfas above proposed safety limits in almost all English waters tested

Exclusive: 110 of 117 bodies of water tested by Environment Agency would fail standards, with levels in fish 322 times the planned limitNearly all rivers, lakes and ponds in England tested for a range of Pfas, known as “forever chemicals”, exceed proposed new safety limits and 85% contain levels at least five times higher, analysis of official data reveals.Out of 117 water bodies tested by the Environment Agency for multiple types of Pfas, 110 would fail the safety standard, according to analysis by Wildlife and Countryside Link and the Rivers Trust. Continue reading...

Nearly all rivers, lakes and ponds in England tested for a range of Pfas, known as “forever chemicals”, exceed proposed new safety limits and 85% contain levels at least five times higher, analysis of official data reveals.Out of 117 water bodies tested by the Environment Agency for multiple types of Pfas, 110 would fail the safety standard, according to analysis by Wildlife and Countryside Link and the Rivers Trust.They also found levels of Pfos – a banned carcinogenic Pfas – in fish were on average 322 times higher than planned limits for wildlife. If just one portion of such freshwater fish was eaten each month this would exceed the safe threshold of Pfos for people to consume over a year, according to the NGOs.Pfas, or per- and polyfluoroalkyl substances, are a group of thousands of human-made chemicals used in industrial processes and products such as non-stick pans, clothing and firefighting foams. They do not break down in the environment and some are linked to diseases, including cancers and hormone disruption.Pfas pollution is widespread, prompting the EU to propose a new water quality standard that limits the combined toxicity of 24 Pfas to 4.4 nanograms per litre of water, calculated as PFOA-equivalents – a method that weights each substance according to its toxicity relative to PFOA, a particularly hazardous and well-studied carcinogen that is now banned.The EU is also planning to regulate about 10,000 Pfas as one class as there are too many to assess on a case-by-case basis and because none break down in the environment, but the UK has no plans to follow suit.Last week, environment groups, led by the Marine Conservation Society, wrote to ministers, urging a ban on all Pfas in consumer products and a timeline for phasing them out in all other uses. Now, public health and nature groups have joined forces to propose urgent measures to rein in pollution.“Scientists continue to identify Pfas as one of the biggest threats of our time, yet the UK is falling behind other countries in restricting them,” said Hannah Evans of the environmental charity Fidra. “Every day of inaction locks in decades of pollution and environmental harm … we’re asking the UK government to turn off the tap of these persistent forever chemicals.”They say the UK should align with the EU’s group-based Pfas restrictions and ban the substances in food packaging, clothing, cosmetics, toys and firefighting foams, following examples from Denmark, France and the EU. They want better monitoring, tougher water and soil standards and to make polluters cover the cost of Pfas clean-up.Emma Adler, the director of impact at Wildlife and Countryside Link, said: “Pfas are linked to an explosion of impacts for wildlife and public health, from cancers to immune issues. These new figures underline just how widespread Pfas pollution is and that Pfas regulation must be a much clearer priority in government missions to clean up UK rivers and improve the nation’s health.”Thalie Martini, the chief executive officer at Breast Cancer UK, said: “Evidence points to the potential for some Pfas to be related to health issues, including increasing breast cancer risk … millions of families affected by this disease will want the government to do everything they can to deliver tougher Pfas rules to protect our health.”Last year, 59 Pfas experts urged the government to follow the science and regulate all Pfas as a single class, warning their extreme persistence – regardless of toxicity – posed a serious environmental threat.skip past newsletter promotionThe planet's most important stories. Get all the week's environment news - the good, the bad and the essentialPrivacy Notice: Newsletters may contain info about charities, online ads, and content funded by outside parties. For more information see our Privacy Policy. We use Google reCaptcha to protect our website and the Google Privacy Policy and Terms of Service apply.after newsletter promotion“Countries like France and Denmark, the EU as a whole and many US states have taken strong action against Pfas pollution,” said Dr Francesca Ginley from the Marine Conservation Society. “The time is now for the UK to take a stand and show the leadership we need on Pfas pollution from source to sea.”Dr Shubhi Sharma of the charity Chem Trust said: “Too often with hazardous chemicals the world has ignored early warnings of harm and learned lessons far too late. Costs to tackle Pfas in the environment and address health impacts have a multi-billion pound economic price tag … the government must not delay.”An Environment Agency spokesperson said the science on Pfas was moving quickly and that it was running a multi-year programme to improve understanding of Pfas pollution sources in England. They added: “We are screening sites to identify potential sources of Pfas pollution and prioritise further investigations, whilst assessing how additional control measures could reduce the risks of Pfas in the environment.”A spokesperson for the Department for Environment, Food and Rural Affairs said: “The government is committed to protecting human health and the environment from the risks posed by Pfas. That’s why we are working at pace together with regulators to assess levels of Pfas in the environment, their sources and potential risks to inform our approach to policy and regulation.”

Breaking Down the Force of Water in the Texas Floods

Flash floods last week in Texas caused the Guadalupe River to rise dramatically, reaching three stories high in just two hours

Over just two hours, the Guadalupe River at Comfort, Texas, rose from hip-height to three stories tall, sending water weighing as much as the Empire State building downstream roughly every minute it remained at its crest.Comfort offers a good lens to consider the terrible force of a flash flood’s wall of water because it’s downstream of where the river’s rain-engorged branches met. The crest was among the highest ever recorded at the spot — flash flooding that appears so fast it can “warp our brains,” said James Doss-Gollin, assistant professor of civil and environmental engineering at Rice University.The Texas flood smashed through buildings, carried away cars and ripped sturdy trees out by the roots, dropping the debris in twisted piles when the water finally ebbed. It killed more than 100 people, prompted scores of rescues and left dozens of others missing. The deaths were concentrated upriver in Kerr County, an area that includes Camp Mystic, the devastated girls' camp, where the water hit early and with little notice.Water is capable of such destruction because it is heavy and can move fast. Just one cubic foot of water — imagine a box a bit larger than the size of a basketball — weighs about 62 pounds (28 kilograms). When the river rose to its peak at Comfort, 177,000 cubic feet — or 11 million pounds (5 million kilograms) of water — flowed by every second.“When you have that little lead time ... that means you can’t wait until the water level starts to rise,” Doss-Gollin said. “You need to take proactive measures to get people to safety.” Water as heavy as a jumbo jet A small amount of water — less than many might think — can sweep away people, cars and homes. Six inches (15.2 centimeters) is enough to knock people off their feet. A couple of feet of fast-moving water can take away an SUV or truck, and even less can move cars.“Suppose you are in a normal car, a normal sedan, and a semitrailer comes and pushes you at the back of the car. That’s the kind of force you’re talking about,” said Venkataraman Lakshmi, a University of Virginia professor and president of the hydrology section of the American Geophysical Union.And at Comfort, it took just over 15 minutes for so much water to arrive that not only could it float away a large pickup truck, but structures were in danger — water as heavy as a jumbo jet moved by every second.At that point, “We are past vehicles, homes and things can start being affected,” said Daniel Henz, flood warning program manager at the flood control district of Maricopa County, Arizona, an area that gets dangerous scary flash floods.The water not only pushes objects but floats them, and that can actually be scarier. The feeling of being pushed is felt immediately, letting a person know they are in danger. Upward force may not be felt until it is overwhelming, according to Upmanu Lall, a water expert at Arizona State University and Columbia University.“The buoyancy happens — it’s like a yes, no situation. If the water reaches a certain depth and it has some velocity, you’re going to get knocked off (your feet) and floating simultaneously,” he said. The mechanics of a flash flood The landscape created the conditions for what some witnesses described as a fast-moving wall of water. Lots of limestone covered by a thin layer of soil in hilly country meant that when rain fell, it ran quickly downhill with little of it absorbed by the ground, according to S. Jeffress Williams, senior scientist emeritus with the U.S. Geological Survey.A flash flood generally starts with an initial lead wave and then builds as rain rushes over the landscape and into the river basin. It may rise quickly, but the water still takes some time to converge. The water crumpled cars into piles, twisted steel and knocked trees down as if they were strands of grass. Images captured the chaos and randomness of the water’s violence.And then, not as fast as it rose, but still quickly, the river receded.Five hours after its crest at Comfort, it had already dropped 10 feet (3 meters), revealing its damage in retreat. A couple of days after it started to rise, a person could stand with their head above the river again.“Everything just can happen, very, very quickly,” Henz said.Associated Press writer Seth Borenstein in Washington contributed.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 - June 2025

South West Water allowed to invest £24m rather than pay £19m fine

Campaigners say Ofwat ‘subservient to industry and its rampaging pursuit of profit’ after illegal sewage dischargesSouth West Water has agreed to pay a £24m penalty for illegal sewage discharges into the environment from its treatment works.The regulator for the water and wastewater sector in England and Wales, Ofwat, says the company, which has 1.8 million customers in Cornwall, Devon, the Isles of Scilly and parts of Dorset and Somerset, is being penalised for dumping sewage in breach of its legal permit conditions. Continue reading...

South West Water has agreed to pay a £24m penalty for illegal sewage discharges into the environment from its treatment works.The regulator for the water and wastewater sector in England and Wales, Ofwat, says the company, which has 1.8 million customers in Cornwall, Devon, the Isles of Scilly and parts of Dorset and Somerset, is being sanctioned for dumping sewage in breach of its legal permit conditions.But there was anger over revelations on Thursday that the regulator had not imposed a direct fine on the company.South West Water put forward the suggestion that it would invest £20m to reduce sewage discharges at key storm overflows, spend £2m to tackle sewer misuse and misconnections, and another £2m to support local environment groups. This was accepted by Ofwat rather than imposing a fine of £19m.But Rob Abrams, the campaigns manager at Surfers Against Sewage, said allowing water companies to choose their own penalty was farcical.He said the situation “illustrates a water industry model that’s broken beyond repair, with government and regulators subservient to industry and its rampaging pursuit of profit, at any cost”.Ofwat said it had chosen this route rather than imposing a fine because it was satisfied that the company would carry out the work required to bring its infrastructure back into legal operation.“We have … concluded that it would be appropriate to accept the undertakings in lieu of the financial penalty we would otherwise impose in this case (£19m, 6.5% of its relevant turnover),” Ofwat said.The regulator carried out a two-year investigation into the company that found it had failed to upgrade its treatment works to prevent sewage discharges into the environment, failed to properly deal with the content of its sewers and failed to put in the resources to monitor its treatment works properly.The penalty is the latest in an ongoing investigation by Ofwat into several water companies into widespread illegal sewage dumping across the network from thousands of treatment plants.Penalties totalling more than £160m have already been imposed against Yorkshire Water, Thames Water and Northumbrian Water for widespread illegal sewage dumping from their treatment works.Lynn Parker, the senior director for enforcement at Ofwat, said the regulator had secured the £24m package and a commitment to put things right from the company.skip past newsletter promotionSign up to Business TodayGet set for the working day – we'll point you to all the business news and analysis you need every morningPrivacy Notice: Newsletters may contain info about charities, online ads, and content funded by outside parties. For more information see our Privacy Policy. We use Google reCaptcha to protect our website and the Google Privacy Policy and Terms of Service apply.after newsletter promotionBut Abrams said it amounted to a cynical PR exercise and an abdication of responsibility by Ofwat.“There is no transparency about how the money will be spent or whether it’s even enough,” he said.“Of the £4m pledged for environmental initiatives and local groups, we’ve been given no clarity on who will benefit or why.”The public and other stakeholders can make representations about the size of the penalty before it is finalised.

Oregon groundwater protection bill passes despite criticism that it’s too weak

Gov. Tina Kotek backed the bill to modernize Oregon’s failed groundwater pollution laws.

Legislators have just passed a groundwater protection bill that many nonprofit groups working on groundwater contamination said was too watered down to make a real difference. Gov. Tina Kotek backed the bill to modernize Oregon’s failed groundwater pollution laws. Kotek has been active in trying to speed up response to the three-decades-old groundwater contamination crisis in the Lower Umatilla Basin, where many residents with nitrate-contaminated domestic wells must rely on bottled drinking water. Until 2022, many people in the region had no idea they had been drinking contaminated water for years. Some still don’t know it because the state has yet to test all the affected wells. A state analysis also has shown that nitrate pollution in the area has worsened significantly over the past decade. Though the state has been testing wells and conducting public awareness campaigns, critics have accused the Oregon Department of Environmental Quality, Department of Agriculture and Water Resources Department of not doing enough to crack down on the pollution sources. Much of the nitrate contamination comes from fertilizer used by large farms, animal manure from local industrial dairies and feedlots and wastewater from food processing plants that are constantly applied to farm fields. Early versions of the bill laid out specific actions that state agencies would have to take once groundwater pollution had reached the level of a serious public health threat. But many of those actions were stripped out of the bill, leading environmental and social justice nonprofits to pull their support because they deemed the bill too weak to make a difference. Oregon Rural Action, the eastern Oregon nonprofit that has been instrumental in testing domestic wells and pushing the state to do more testing and to limit nitrate pollution, said industry groups representing polluters put pressure on the governor’s office, leading to major changes in the bill’s language. “The version passed on Friday no longer includes the tools, resources, and Legislative directives needed for agencies to exercise their authority to protect Oregon’s groundwater and enforce the law,”the group’s executive director, Kristin Anderson Ostrom, said in a statement. The governor’s office declined to comment.Kotek in January issued an emergency order allowing the Port of Morrow to again violate its water pollution permit and over-apply nitrogen contaminated water onto farmland. The port, which handles billions of gallons of nitrogen-rich water every year, said that it would have to pause operations and lay off workers if not for the emergency permit. In addition to the Lower Umatilla Basin, Oregon has designated two other areas – in northern Malheur County and the southern Willamette Valley – where elevated nitrate concentrations in groundwater pose a human health risk. Each one has an action plan to reduce nitrate concentrations in groundwater. Research has linked high nitrate consumption over long periods to stomach, bladder and intestinal cancers, miscarriages and thyroid issues. It is especially dangerous to infants who can quickly develop “blue baby syndrome,” a fatal illness.— Gosia Wozniacka covers environmental justice, climate change, the clean energy transition and other environmental issues. Reach her at gwozniacka@oregonian.com or 971-421-3154.

A rare glimpse inside the mountain tunnel that carries water to Southern California

In the 1930s, workers bored a 13-mile tunnel beneath Mt. San Jacinto. Here's a look inside the engineering feat that carries Colorado River water to Southern California.

Thousands of feet below the snowy summit of Mt. San Jacinto, a formidable feat of engineering and grit makes life as we know it in Southern California possible. The 13-mile-long San Jacinto Tunnel was bored through the mountain in the 1930s by a crew of about 1,200 men who worked day and night for six years, blasting rock and digging with machinery. Completed in 1939, the tunnel was a cornerstone in the construction of the 242-mile Colorado River Aqueduct. It enabled the delivery of as much as 1 billion gallons of water per day.The tunnel is usually off-limits when it is filled and coursing with a massive stream of Colorado River water. But recently, while it was shut down for annual maintenance, the Metropolitan Water District of Southern California opened the west end of the passage to give The Times and others a rare look inside. “It’s an engineering marvel,” said John Bednarski, an assistant general manager of MWD. “It’s pretty awe-inspiring.” The 16-foot-diameter San Jacinto Tunnel runs 13 miles through the mountain. While shut down for maintenance, the tunnel has a constant stream of water entering from the mountain. A group visits the west end of the San Jacinto Tunnel, where the mouth of the water tunnel enters a chamber. He wore a hard hat as he led a group to the gaping, horseshoe-shaped mouth of the tunnel. The passage’s concrete arch faded in the distance to pitch black.The tunnel wasn’t entirely empty. The sound of rushing water echoed from the walls as an ankle-deep stream flowed from the portal and cascaded into a churning pool beneath metal gates. Many in the tour group wore rubber boots as they stood on moist concrete in a chamber faintly lit by filtered sunlight, peering into the dark tunnel. This constant flow comes as groundwater seeps and gushes from springs that run through the heart of the mountain. In places deep in the tunnel, water shoots so forcefully from the floor or the wall that workers have affectionately named these soaking obstacles “the fire hose” and “the car wash.”Standing by the flowing stream, Bednarski called it “leakage water from the mountain itself.”Mt. San Jacinto rises 10,834 feet above sea level, making it the second-highest peak in Southern California after 11,503-foot Mt. San Gorgonio.As the tunnel passes beneath San Jacinto’s flank, as much as 2,500 feet of solid rock lies overhead, pierced only by two vertical ventilation shafts. Snow covers Mt. San Jacinto, as seen from Whitewater, in March. At the base of the mountain, the 13-mile San Jacinto Tunnel starts its journey. The tunnel transports Colorado River water to Southern California’s cities. During maintenance, workers roll through on a tractor equipped with a frame bearing metal bristles that scrape the tunnel walls, cleaning off algae and any growth of invasive mussels. Workers also inspect the tunnel by passing through on an open trailer, scanning for any cracks that require repairs.“It’s like a Disneyland ride,” said Bryan Raymond, an MWD conveyance team manager. “You’re sitting on this trailer, and there’s a bunch of other people on it too, and you’re just cruising through looking at the walls.” Aside from the spraying and trickling water, employee Michael Volpone said he has also heard faint creaking.“If you sit still and listen, you can kind of hear the earth move,” he said. “It’s a little eerie.”Standing at the mouth of the tunnel, the constant babble of cascading water dominates the senses. The air is moist but not musty. Put a hand to the clear flowing water, and it feels warm enough for a swim. On the concrete walls are stained lines that extend into the darkness, marking where the water often reaches when the aqueduct is running full. Many who have worked on the aqueduct say they are impressed by the system’s design and how engineers and workers built such a monumental system with the basic tools and technology available during the Great Depression.Pipelines and tunnelsThe search for a route to bring Colorado River water across the desert to Los Angeles began with the signing of a 1922 agreement that divided water among seven states. After the passage of a $2-million bond measure by Los Angeles voters in 1925, hundreds of surveyors fanned out across the largely roadless Mojave and Sonoran deserts to take measurements and study potential routes.The surveyors traveled mostly on horseback and on foot as they mapped the rugged terrain, enduring grueling days in desert camps where the heat sometimes topped 120 degrees.Planners studied and debated more than 100 potential paths before settling on one in 1931. The route began near Parker, Ariz., and took a curving path through desert valleys, around obstacles and, where there was no better option, through mountains.In one official report, a manager wrote that “to bore straight through the mountains is very expensive and to pump over them is likewise costly.” He said the planners carefully weighed these factors as they decided on a solution that would deliver water at the lowest cost. VIDEO | 02:45 A visit to the giant tunnel that brings Colorado River water to Southern California Share via Those in charge of the Metropolitan Water District, which had been created in 1928 to lead the effort, were focused on delivering water to 13 participating cities, including Los Angeles, Burbank and Anaheim. William Mulholland, Los Angeles’ chief water engineer, had led an early scouting party to map possible routes from the Colorado River to Southern California’s cities in 1923, a decade after he celebrated the completion of the 233-mile aqueduct from the Owens Valley to Los Angeles with the triumphant words, “There it is. Take it.”The aqueduct’s design matched the audaciousness of the giant dams the federal government was starting to build along the Colorado — Hoover Dam (originally called Boulder Dam) and Parker Dam, which formed the reservoir where the aqueduct would begin its journey.Five pumping plants would be built to lift water more than 1,600 feet along the route across the desert. Between those points, water would run by gravity through open canals, buried pipelines and 29 separate tunnels stretching 92 miles — the longest of which was a series of nine tunnels running 33.7 miles through hills bordering the Coachella Valley.To make it possible, voters in the district’s 13 cities overwhelmingly approved a $220-million bond in 1931, the equivalent of a $4.5-billion investment today, which enabled the hiring of 35,000 workers. Crews set up camps, excavated canals and began to blast open shafts through the desert’s rocky spines to make way for water.In 1933, workers started tearing into the San Jacinto Mountains at several locations, from the east and the west, as well as excavating shafts from above. Black-and-white photographs and films showed miners in hard hats and soiled uniforms as they stood smoking cigarettes, climbing into open rail cars and running machinery that scooped and loaded piles of rocks.Crews on another hulking piece of equipment, called a jumbo, used compressed-air drills to bore dozens of holes, which were packed with blasting power and detonated to pierce the rock. (Courtesy of Metropolitan Water District of Southern California) The work progressed slowly, growing complicated when the miners struck underground streams, which sent water gushing in.According to a 1991 history of the MWD titled “A Water Odyssey,” one flood in 1934 disabled two of three pumps that had been brought in to clear the tunnel. In another sudden flood, an engineer recalled that “the water came in with a big, mad rush and filled the shaft to the top. Miners scrambled up the 800-foot ladder to the surface, and the last man out made it with water swirling around his waist.”Death and delaysAccording to the MWD’s records, 13 workers died during the tunnel’s construction, including men who were struck by falling rocks, run over by equipment or electrocuted with a wire on one of the mining trolleys that rolled on railroad tracks. The Metropolitan Water District had originally hired Wenzel & Henoch Construction Co. to build the tunnel. But after less than two years, only about two miles of the tunnel had been excavated, and the contractor was fired by MWD general manager Frank Elwin “F.E.” Weymouth, who assigned the district’s engineers and workers to complete the project.Construction was delayed again in 1937 when workers went on strike for six weeks. But in 1939, the last wall of rock tumbled down, uniting the east and west tunnels, and the tunnel was finished. John Bednarski, assistant general manager of the Metropolitan Water District of Southern California, stands in a water tunnel near the end point of the larger San Jacinto Tunnel, which carries Colorado River water. The total cost was $23.5 million. But there also were other costs. As the construction work drained water, many nearby springs used by the Native Soboba people stopped flowing. The drying of springs and creeks left the tribe’s members without water and starved their farms, which led to decades of litigation by the Soboba Band of Luiseño Indians and eventually a legal settlement in 2008 that resolved the tribe’s water rights claims.The ‘magic touch’ of waterBy the time the tunnel was completed, the Metropolitan Water District had released a 20-minute film that was shown in movie theaters and schools celebrating its conquest of the Colorado River and the desert. It called Mt. San Jacinto the “tallest and most forbidding barrier.”In a rich baritone, the narrator declared Southern California “a new empire made possible by the magic touch of water.” “Water required to support this growth and wealth could not be obtained from the local rainfall in this land of sunshine,” the narrator said as the camera showed newly built homes and streets filled with cars and buses. “The people therefore realized that a new and dependable water supply must be provided, and this new water supply has been found on the lofty western slopes of the Rocky Mountains, a wonderland of beauty, clad by nature in a white mantle of snow.”Water began to flow through the aqueduct in 1939 as the pumping plants were tested. At the Julian Hinds Pumping Plant, near the aqueduct’s halfway point, water was lifted 441 feet, surging through three pipelines up a desert mountain. March 2012 image of the 10-foot-diameter delivery lines carrying water 441 feet uphill from the Julian Hinds Pumping Plant. (Los Angeles Times) From there, the water flowed by gravity, moving at 3-6 mph as it traveled through pipelines, siphons and tunnels. It entered the San Jacinto Tunnel in Cabazon, passed under the mountain and emerged near the city of San Jacinto, then continued in pipelines to Lake Mathews reservoir in Riverside County. In 1941, Colorado River water started flowing to Pasadena, Beverly Hills, Compton and other cities. Within six years, another pipeline was built to transport water from the aqueduct south to San Diego.The influx of water fueled Southern California’s rapid growth during and after World War II.Over decades, the dams and increased diversions also took an environmental toll, drying up much of the once-vast wetlands in Mexico’s Colorado River Delta. John Bednarski, assistant general manager of the Metropolitan Water District, walks in a water tunnel near the end point of the larger San Jacinto Tunnel. An impressive designToday, 19 million people depend on water delivered by the MWD, which also imports supplies from Northern California through the aqueducts and pipelines of the State Water Project.In recent decades, the agency has continued boring tunnels where needed to move water. A $1.2-billion, 44-mile-long conveyance system called the Inland Feeder, completed in 2009, involved boring eight miles of tunnels through the San Bernardino Mountains and another 7.9-mile tunnel under the Badlands in Riverside County.The system enabled the district to increase its capacity and store more water during wet years in Diamond Valley Lake, Southern California’s largest reservoir, which can hold about 260 billion gallons of water. “Sometimes tunneling is actually the most effective way to get from point A to point B,” said Deven Upadhyay, the MWD’s general manager.Speaking hypothetically, Upadhyay said, if engineers had another shot at designing and building the aqueduct now using modern technology, it’s hard to say if they would end up choosing the same route through Mt. San Jacinto or a different route around it. But the focus on minimizing cost might yield a similar route, he said.“Even to this day, it’s a pretty impressive design,” Upadhyay said.When people drive past on the I-10 in Cabazon, few realize that a key piece of infrastructure lies hidden where the desert meets the base of the mountain. At the tunnel’s exit point near San Jacinto, the only visible signs of the infrastructure are several concrete structures resembling bunkers. When the aqueduct is running, those who enter the facility will hear the rumble of rushing water. The tunnel’s west end was opened to a group of visitors in March, when the district’s managers held an event to name the tunnel in honor of Randy Record, who served on the MWD board for two decades and was chair from 2014 to 2018. Speaking to an audience, Upadhyay reflected on the struggles the region now faces as the Colorado River is sapped by drought and global warming, and he drew a parallel to the challenges the tunnel’s builders overcame in the 1930s. “They found a path,” Upadhyay said. “This incredible engineering feat. And it required strength, courage and really an innovative spirit.” “When we now think about the challenges that we face today, dealing with wild swings in climate and the potential reductions that we might face, sharing dwindling supplies on our river systems with the growing Southwest, it’s going to require the same thing — strength, courage and a spirit of innovation,” he said. A steep steel staircase gives access to a water tunnel near the end point of the larger San Jacinto Tunnel, which carries Colorado River water to Southern California.

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