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GROUNDWATER
Do you know the difference between groundwater and surface water?
- Surface water is the residue of precipitation and melted snow, called runoff. It forms bodies of water such as streams, rivers, and lakes.
- Groundwater is water that infiltrates Earth’s surface and slowly seeps downward into extensive layers of porous soil and rock called aquifers.
- Surface water has lesser mineral and salt content, while groundwater has high mineral content.
- Surface water includes any freshwater that’s sent into wetlands, stream systems, and lakes, while groundwater exists in subterranean aquifers that are situated underground.
- The main uses of surface water include drinking-water and other public uses, irrigation uses, and for use by the thermoelectric-power industry to cool electricity-generating equipment.
- Groundwater and surface water physically overlap at the groundwater/surface water interface through the exchange of water and chemicals.
Tools for Managing Groundwater in the Hill Country
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It is often said that water is the lifeblood of the Texas Hill Countr y– but the real credit for our region’s success is the water we cannot see: our region’s groundwater supply. Hill Country groundwater is a drinking water source for countless communities – from small rural cities like Bandera and Leakey, to fast developing communities like Fredericksburg and New Braunfels, to our region’s largest metropolis – San Antonio. Groundwater also feeds our crystal clear rivers – 12 of the state’s 15 major rivers have their headwaters in the Hill Country and receive inflows from springs. However, the Hill Country is growing at a staggering rate. New developments are placing increasing demand on our aquifers at the same time that the region is experiencing more frequent drought. Most of this growth is happening in unincorporated areas where regulation is limited.
In the face of such unprecedented change, we must use every tool to manage groundwater for the people, plants, and animals that call the Hill Country home. In this new resource, we demystify those available tools and lay out the opportunities for Groundwater Conservation Districts, counties, cities, and residents of the Hill Country to get involved in the protection of these critical waters for current and future generations. |
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Material adapted from: Vandas, S.J., Winter, T.C., and Battaglin, W.A. 2002. Water and the Environment, p. 28-29. Published by the American Geosciences Institute Environmental Awareness Series.
How do groundwater and surface water interact?
Surface water and groundwater systems are connected in most landscapes. Streams interact with groundwater in three basic ways: streams gain water from inflow of groundwater through the streambed, streams lose water by outflow through the streambed, or they do both depending upon the location along the stream. It is the groundwater contribution that keeps streams flowing between precipitation events or after snowmelt. For a stream to gain water, the elevation of the water table in the vicinity of the stream must be higher than the streamwater surface. For a stream to lose water to groundwater, the water table must be below the elevation of the stream-water surface in the vicinity of the stream. If the water table has large variations during the year, a stream segment could receive water from groundwater for a portion of the year and lose water to groundwater at other times.
Surface-water bodies such as lakes and wetlands can receive groundwater inflow, recharge groundwater, or do both. The movement of water between groundwater and surface-water systems leads to the mixing of their water qualities. High quantities of nutrients or other dissolved chemicals in surface water can be transferred to the connected groundwater system.
Learn More
Surface-water bodies such as lakes and wetlands can receive groundwater inflow, recharge groundwater, or do both. The movement of water between groundwater and surface-water systems leads to the mixing of their water qualities. High quantities of nutrients or other dissolved chemicals in surface water can be transferred to the connected groundwater system.
Learn More
- Water as One Resource (Webinar), American Geosciences Institute
Three presentations covering how groundwater and surface water interact, what the implications of these interactions on water resources are, and how water can be more effectively managed if an understanding of these interactions is incorporated.
- Ground Water and Surface Water: A Single Resource (Handbook), U.S. Geological Survey
A comprehensive overview of groundwater and surface-water interactions for a general audience. Covers natural processes of interaction (interactions in the hydrologic cycle, chemical interactions of groundwater and surface water, interactions in different landscapes), effects of human activities on groundwater and surface-water interactions, and challenges and opportunities in these interactions. - Ground Water and Surface Water Interactions (Website), U.S. Geological Survey
This website pulls together technical and general publications, project websites, and technical models related to groundwater and surface water interactions.
PHOTOGRAPH: DAVID SCHLESER/GETTY IMAGES
A Strange, Endangered Ecosystem Hides in Underground Waterways
In an increasingly thirsty world, scientists warn that the rare creatures living in our groundwater are at risk.
By James Gaines
February 12, 2022
THIS STORY ORIGINALLY appeared on Undark and is part of the Climate Desk collaboration.
“I DON'T KNOW that there’s much to prepare you for entering a black hole,” said Ruben Tovar. In the fall of 2021, Tovar was outside of San Antonio, Texas, preparing to enter a hole in the ground the size of an oven door—the entrance to a cave carved out of the limestone.
Equipped with climbing gear and flashlights, Tovar and his caving partner descended into gloom, shimmying down a roughly three-story near-vertical tunnel and brushing up against colonies of spindly-legged cave crickets. Along the way, Tovar could see water seeping through the limestone walls. There had been storms the week before and the rain was slowly percolating into the Edwards Aquifer, a vast reservoir of fresh water below.
Tovar was looking for salamanders. While many people might more readily picture a salamander hiding under a log, the Texan underground is home to a subterranean aquatic ecosystem rich in these lizard-like amphibians, as well as invertebrates and fish, hidden where humans can barely visit.
Groundwater—held in caves, pores, and cracks—is actually the world’s largest unfrozen freshwater habitat, containing more water than all lakes and rivers combined. And where there is water, there is life. Often blind, pale, and adapted to live in near starvation, these groundwater-dwelling animals—known as stygofauna—are poorly understood and difficult to study.
But lately scientists from France to India and Australia are using genetic and chemical techniques to better understand stygofauna—and warning that many of these strange creatures may soon face extinction, including Texas’ salamanders. Many people rely on groundwater for drinking and domestic use, and in the past it has often been treated like an infinite resource. But groundwater is already running out in many areas. And the world is going to get even thirstier in the coming century: According to the World Meteorological Organization, by 2050, 5 billion people may lack adequate access to water.
How much are humans willing to do—or give up—to save an ecosystem that’s largely impossible to visit or even see? And if this ecosystem is damaged, what is at stake?
Conserving salamanders and other underground life is a “huge deal,” said Tovar, “because they rely on the water that we rely on.” The health of underwater ecosystems can act as a barometer for the health of everything living aboveground, too, including people. And when it comes to understanding underwater ecosystems, Tovar added, “we’ve only scratched the surface.”
RESEARCHERS HAVE KNOWN about Texas’ underground salamanders for more than a century, ever since a dozen or so turned up in a newly drilled well in San Marcos in 1895. But finding more has often been pure accident. Workers digging up a spring near a dry riverbed in 1951, for instance, discovered four specimens of a species now known as the Blanco blind salamander, but left unattended, the story goes, two were quickly eaten by a heron. Another was lost, leaving science with only a single specimen of the species to this day.
Scientists have been able to find the salamanders by venturing underground, but such fieldwork is laborious and sometimes dangerous. Caves can hold venomous animals, pockets of suffocating gas, and other hazards. And considering the salamanders’ low population densities, finding one is a shot in the dark, with many expeditions returning empty-handed. (The same was true for Tovar when he went spelunking in that San Antonio cave in 2021: Like many times before, he did not find any salamanders.)
But even without live specimens, scientists can return with something else of value. Using a technique called environmental DNA, or eDNA, they can check for bits of genetic material from skin cells, waste, or other biological cast-offs to track and identify animals.
TOM DEVITT AND THE TEXAS SALAMANDER
One of the people using eDNA to find groundwater fauna is Tom Devitt, an evolutionary biologist at the University of Texas at Austin (Devitt and Tovar work together in evolutionary biologist David Hillis’ lab). Since 2013, Devitt has been working to find and map rare Texan salamanders. His work has revealed the existence of three previously unknown species of salamander, as well as the borders of the animals’ ranges. It turns out the caves under the state are isolated from one another by water flow and a dearth of nutrients, dividing the salamanders into many different species. By knowing where salamanders are found, scientists and policymakers can figure out which areas need study or protection.
For the past year or so, Devitt has been working with eDNA to better map these salamanders and their ranges, especially in places where they haven’t been found before. The work involves taking several liters of groundwater from rivers, streams, or caves, filtering to collect samples, and then running the samples through machines that can detect traces of specific DNA.
“The first step is just figuring out who’s who, right? And who lives where. And that’s kind of the most basic question, that we’re still struggling with,” said Devitt. “I mean, people have been studying these salamanders for, gosh, over a hundred years.” What’s more, figuring out distributions can also give clues to the salamander’s evolution and habits.
eDNA
Devitt isn’t the only scientist using these new techniques. Researchers have also used eDNA to find a rare cave crayfish in Alabama and to map out where to find long, pale, aquatic salamanders called olms, in Croatia. Australian scientists have used eDNA to investigate what kind of creatures live in the caves under Christmas Island, revealing a diverse community that includes a type of fish called snook, yellow nipper crabs, and freshwater jellyfish.
Even so, eDNA has limitations. As biologists Melania Cristescu and Paul Hebert outlined in a 2018 review, eDNA can have both false negatives and false positives. If a scientist doesn’t get any DNA results from a sample, it might not truly mean the species is missing, for instance, as genetic material can break down quickly before it’s detected. And getting a positive might not mean much for a specific location if a strong current is bringing in material from far away.
Environmental DNA also draws from existing databases of genetic material, so if the database is wrong, the approach might give a false reading or misidentify a species. (Part of what Tovar and Devitt are doing is trying to get rare salamander DNA samples in order to improve the reliability and sensitivity of their eDNA tests.)
Still, “molecular technologies have changed the game,” says Grant Hose, an aquatic ecologist and ecotoxicologist at Macquarie University in Sydney, Australia, who has used eDNA to show that metal contamination from Australian mines can affect subterranean creatures more than 10 miles downstream.
Also in Australia, Mattia Saccò, a researcher at Curtin University in Perth, is using a different technique to study the groundwater ecosystems. Instead of tracking minute traces of DNA, Saccò is looking at the proportions of atoms—called isotope analysis—to see how different forms of elements such as carbon or nitrogen are flowing through the ecosystem. He’s been able to map the food web of subterranean fauna and how it changes over time, such as when rains appear at the end of Western Australia’s dry season.
“I was actually able to see how rainfall was being incorporated within the system,” said Saccò. In the dry season, food was scarce and much of the nutrients came from plant roots; the rains brought a glut of fresh nutrients from the surface. This change then rippled throughout the food web—even up to some of the system’s top predators, beetle larvae, which switched from a more opportunistic diet to one more specialized on small crustaceans.
Research is also starting to reveal what might happen if underground ecosystems and animals disappear. Tovar is looking into whether understanding how blind salamanders lost their sight might translate to human vision, for example. Stygofauna may also provide what’s known as ecosystem services—research has suggested that the creatures could help purify groundwater by removing contaminants or pathogens.
“We are actually able to enjoy and to profit from groundwater because these bugs are doing the work for us and keeping the groundwater clean,” said Saccò.
EVEN THOUGH SCIENTISTS continue to learn more about stygofauna, in reality, the few well-studied hotspots represent only a fraction of the world’s groundwater ecosystems. In other parts of the world, particularly Asia and Africa, little relevant work has been done, Saccò said. And without better knowledge about the denizens of these habitats, they may go extinct.
GREATER PRESSURE ON THE EDWARDS AQUIFER
One key pressure is the demand for more water. According to US Census Bureau data, Austin, the state capital of Texas, is among the fastest-growing large cities in the country, which is putting greater demands on the Edwards-Trinity aquifer system.
GROUNDWATER OVERDRAFT
Austin isn’t alone. Groundwater overdraft is an intensifying global problem, and it’s estimated that current demand is more than three times the actual volume of aquifers. According to a 2019 assessment by researchers in Vietnam, Australia, and Italy, roughly a third of the world’s largest groundwater systems are already in distress. And according to a 2016 model from hydrologists at Urecht University in the Netherlands, areas like Italy and part of the High Plains in the US could reach their limits by the 2040s to 2070s; California’s Central Valley may exhaust its aquifer as soon as the 2030s.
India’s Western Ghats—a mountain chain that runs down the country’s southwestern coast—may also struggle. The Western Ghats are home to many unusual subterranean freshwater fish, including the dragon snakehead, which looks like an armored eel and may represent a relic population that’s existed for a hundred million years. But the region is also densely populated by humans, putting tremendous pressure on its aquifers. By 2050, more than 80 million people there may have insufficient water.
Invasive species pose another threat, such as catfish or tilapia in the Western Ghats and the American red swamp crayfish in Europe, which have invaded wells and caves.
Groundwater ecosystems also face pollution. Some of this is accidental contamination from mining spoils or agricultural fertilizers. And some is purposeful, like in Slovenia, where a capacitor factory disposed of toxic waste for two decades by simply pouring it into sinkholes, contaminating olm habitats, or in India, where it’s common practice to use chemicals to disinfect wells.
BARTON SPRINGS POOL
IN SOME CASES, legislation and lawsuits have forced the preservation of at least some stygofauna. Barton Springs Pool is a deep, cold, spring-fed recreational pool near downtown Austin and has been a popular swimming venue for more than a century. (Long before the pool was built up, the springs themselves were used by Indigenous people). For some of that time, the city kept the natural pool in welcoming conditions for human visitors using intensive cleaning methods like hot water, high-pressure hoses, and chlorine.
But humans aren’t the only creatures there—deep in the springs that feed the pool live two different salamander species: the Barton Springs salamander, officially named in 1993, and the Austin blind salamander, discovered in 2001.
In 1992, the citizens of Austin passed an ordinance that restricted development in the recharge zones and limited pollution in the springs. That year, the city also stopped using chlorine to control algae at the pool. After the federal government listed the Barton Springs salamander as endangered in accordance with the Endangered Species Act in 1997, other practices were changed to protect the salamanders. Today, as part of an agreement with the US Fish and Wildlife Service, the city can still use the pool for swimming and can clean it (though with less destructive methods: High-pressure washing in salamander habitats is banned, and dropping the water level for cleaning is restricted). But in return, the city also has to help protect the ecosystem.
SALAMANDER BREEDING PROGRAM
In 1998, as part of that protection, Austin launched a captive breeding program for the salamanders. Now a captive population of about 240 Barton Springs salamanders and about 50 Austin blind salamanders live inside a small facility a few minutes from the springs.
“Our whole goal, and it’s a pretty standard goal for captive breeding programs, is to maintain 90 percent gene diversity for a hundred years,” said Dee Ann Chamberlain, an environmental scientist and the head of the program.
In addition to allowing for the study of the animals, the program also provides a failsafe in case of disaster. Barton Springs depends on water that enters the aquifer and flows in from the surface through nearby areas called recharge zones. A nearby chemical spill from, say, a crashed tanker truck or industrial accident could spell disaster for the salamanders.
“You could have a contaminant spill reach the springs in about a day,” said Chamberlain. “So there’s very real threats to the species.”
In that case, Chamberlain and her team would scoop up as many of the rare creatures from the wild as possible to bring back to the center before the contamination arrived. One day, when it was deemed safe, the scientists say they would return the salamanders’ babies to the springs.
PROTECTING RECHARGE ZONES
Of course, protecting these zones from contamination would be better than trying to fix things after the fact. To that end, Austin has purchased land in the recharge zones and plans to purchase more, said Scott Hiers, a geoscientist employed by the city. This will limit development in those areas, he added, helping reduce the risk of pollution and ensuring surface water can trickle down to the aquifer.
“The land protection strategy is sort of the gold standard in my mind,” said Devitt. “The ultimate goal is to protect and preserve the watersheds that support these species.”
Development has also been stymied by lawsuits, such as one filed by the Center for Biological Diversity in 2019 alleging that highway construction could threaten Austin’s salamanders. The Endangered Species Act has also resulted in restrictions on groundwater usage in Texas.
Other parts of the world have also made efforts to protect stygofauna: The Western Australian government, for instance, has required that the subterranean fauna be considered in environmental assessments since the mid-1990s, and in India, new fees and stricter laws around groundwater use may provide additional protection, though conservationists have said more will need to be done.
But pressures on the ecosystems still remain.
“So not to paint a very bleak picture, but I think that it’s certainly going to be very challenging moving forward to keep some of these populations, if not species, from going extinct,” said Devitt. “That’s just the reality of it. I mean, one of the most recent species we discovered was right in the middle of a small city that’s only getting bigger. Salamanders are amazing at persisting, but only to a point.”
February 12, 2022
THIS STORY ORIGINALLY appeared on Undark and is part of the Climate Desk collaboration.
“I DON'T KNOW that there’s much to prepare you for entering a black hole,” said Ruben Tovar. In the fall of 2021, Tovar was outside of San Antonio, Texas, preparing to enter a hole in the ground the size of an oven door—the entrance to a cave carved out of the limestone.
Equipped with climbing gear and flashlights, Tovar and his caving partner descended into gloom, shimmying down a roughly three-story near-vertical tunnel and brushing up against colonies of spindly-legged cave crickets. Along the way, Tovar could see water seeping through the limestone walls. There had been storms the week before and the rain was slowly percolating into the Edwards Aquifer, a vast reservoir of fresh water below.
Tovar was looking for salamanders. While many people might more readily picture a salamander hiding under a log, the Texan underground is home to a subterranean aquatic ecosystem rich in these lizard-like amphibians, as well as invertebrates and fish, hidden where humans can barely visit.
Groundwater—held in caves, pores, and cracks—is actually the world’s largest unfrozen freshwater habitat, containing more water than all lakes and rivers combined. And where there is water, there is life. Often blind, pale, and adapted to live in near starvation, these groundwater-dwelling animals—known as stygofauna—are poorly understood and difficult to study.
But lately scientists from France to India and Australia are using genetic and chemical techniques to better understand stygofauna—and warning that many of these strange creatures may soon face extinction, including Texas’ salamanders. Many people rely on groundwater for drinking and domestic use, and in the past it has often been treated like an infinite resource. But groundwater is already running out in many areas. And the world is going to get even thirstier in the coming century: According to the World Meteorological Organization, by 2050, 5 billion people may lack adequate access to water.
How much are humans willing to do—or give up—to save an ecosystem that’s largely impossible to visit or even see? And if this ecosystem is damaged, what is at stake?
Conserving salamanders and other underground life is a “huge deal,” said Tovar, “because they rely on the water that we rely on.” The health of underwater ecosystems can act as a barometer for the health of everything living aboveground, too, including people. And when it comes to understanding underwater ecosystems, Tovar added, “we’ve only scratched the surface.”
RESEARCHERS HAVE KNOWN about Texas’ underground salamanders for more than a century, ever since a dozen or so turned up in a newly drilled well in San Marcos in 1895. But finding more has often been pure accident. Workers digging up a spring near a dry riverbed in 1951, for instance, discovered four specimens of a species now known as the Blanco blind salamander, but left unattended, the story goes, two were quickly eaten by a heron. Another was lost, leaving science with only a single specimen of the species to this day.
Scientists have been able to find the salamanders by venturing underground, but such fieldwork is laborious and sometimes dangerous. Caves can hold venomous animals, pockets of suffocating gas, and other hazards. And considering the salamanders’ low population densities, finding one is a shot in the dark, with many expeditions returning empty-handed. (The same was true for Tovar when he went spelunking in that San Antonio cave in 2021: Like many times before, he did not find any salamanders.)
But even without live specimens, scientists can return with something else of value. Using a technique called environmental DNA, or eDNA, they can check for bits of genetic material from skin cells, waste, or other biological cast-offs to track and identify animals.
TOM DEVITT AND THE TEXAS SALAMANDER
One of the people using eDNA to find groundwater fauna is Tom Devitt, an evolutionary biologist at the University of Texas at Austin (Devitt and Tovar work together in evolutionary biologist David Hillis’ lab). Since 2013, Devitt has been working to find and map rare Texan salamanders. His work has revealed the existence of three previously unknown species of salamander, as well as the borders of the animals’ ranges. It turns out the caves under the state are isolated from one another by water flow and a dearth of nutrients, dividing the salamanders into many different species. By knowing where salamanders are found, scientists and policymakers can figure out which areas need study or protection.
For the past year or so, Devitt has been working with eDNA to better map these salamanders and their ranges, especially in places where they haven’t been found before. The work involves taking several liters of groundwater from rivers, streams, or caves, filtering to collect samples, and then running the samples through machines that can detect traces of specific DNA.
“The first step is just figuring out who’s who, right? And who lives where. And that’s kind of the most basic question, that we’re still struggling with,” said Devitt. “I mean, people have been studying these salamanders for, gosh, over a hundred years.” What’s more, figuring out distributions can also give clues to the salamander’s evolution and habits.
eDNA
Devitt isn’t the only scientist using these new techniques. Researchers have also used eDNA to find a rare cave crayfish in Alabama and to map out where to find long, pale, aquatic salamanders called olms, in Croatia. Australian scientists have used eDNA to investigate what kind of creatures live in the caves under Christmas Island, revealing a diverse community that includes a type of fish called snook, yellow nipper crabs, and freshwater jellyfish.
Even so, eDNA has limitations. As biologists Melania Cristescu and Paul Hebert outlined in a 2018 review, eDNA can have both false negatives and false positives. If a scientist doesn’t get any DNA results from a sample, it might not truly mean the species is missing, for instance, as genetic material can break down quickly before it’s detected. And getting a positive might not mean much for a specific location if a strong current is bringing in material from far away.
Environmental DNA also draws from existing databases of genetic material, so if the database is wrong, the approach might give a false reading or misidentify a species. (Part of what Tovar and Devitt are doing is trying to get rare salamander DNA samples in order to improve the reliability and sensitivity of their eDNA tests.)
Still, “molecular technologies have changed the game,” says Grant Hose, an aquatic ecologist and ecotoxicologist at Macquarie University in Sydney, Australia, who has used eDNA to show that metal contamination from Australian mines can affect subterranean creatures more than 10 miles downstream.
Also in Australia, Mattia Saccò, a researcher at Curtin University in Perth, is using a different technique to study the groundwater ecosystems. Instead of tracking minute traces of DNA, Saccò is looking at the proportions of atoms—called isotope analysis—to see how different forms of elements such as carbon or nitrogen are flowing through the ecosystem. He’s been able to map the food web of subterranean fauna and how it changes over time, such as when rains appear at the end of Western Australia’s dry season.
“I was actually able to see how rainfall was being incorporated within the system,” said Saccò. In the dry season, food was scarce and much of the nutrients came from plant roots; the rains brought a glut of fresh nutrients from the surface. This change then rippled throughout the food web—even up to some of the system’s top predators, beetle larvae, which switched from a more opportunistic diet to one more specialized on small crustaceans.
Research is also starting to reveal what might happen if underground ecosystems and animals disappear. Tovar is looking into whether understanding how blind salamanders lost their sight might translate to human vision, for example. Stygofauna may also provide what’s known as ecosystem services—research has suggested that the creatures could help purify groundwater by removing contaminants or pathogens.
“We are actually able to enjoy and to profit from groundwater because these bugs are doing the work for us and keeping the groundwater clean,” said Saccò.
EVEN THOUGH SCIENTISTS continue to learn more about stygofauna, in reality, the few well-studied hotspots represent only a fraction of the world’s groundwater ecosystems. In other parts of the world, particularly Asia and Africa, little relevant work has been done, Saccò said. And without better knowledge about the denizens of these habitats, they may go extinct.
GREATER PRESSURE ON THE EDWARDS AQUIFER
One key pressure is the demand for more water. According to US Census Bureau data, Austin, the state capital of Texas, is among the fastest-growing large cities in the country, which is putting greater demands on the Edwards-Trinity aquifer system.
GROUNDWATER OVERDRAFT
Austin isn’t alone. Groundwater overdraft is an intensifying global problem, and it’s estimated that current demand is more than three times the actual volume of aquifers. According to a 2019 assessment by researchers in Vietnam, Australia, and Italy, roughly a third of the world’s largest groundwater systems are already in distress. And according to a 2016 model from hydrologists at Urecht University in the Netherlands, areas like Italy and part of the High Plains in the US could reach their limits by the 2040s to 2070s; California’s Central Valley may exhaust its aquifer as soon as the 2030s.
India’s Western Ghats—a mountain chain that runs down the country’s southwestern coast—may also struggle. The Western Ghats are home to many unusual subterranean freshwater fish, including the dragon snakehead, which looks like an armored eel and may represent a relic population that’s existed for a hundred million years. But the region is also densely populated by humans, putting tremendous pressure on its aquifers. By 2050, more than 80 million people there may have insufficient water.
Invasive species pose another threat, such as catfish or tilapia in the Western Ghats and the American red swamp crayfish in Europe, which have invaded wells and caves.
Groundwater ecosystems also face pollution. Some of this is accidental contamination from mining spoils or agricultural fertilizers. And some is purposeful, like in Slovenia, where a capacitor factory disposed of toxic waste for two decades by simply pouring it into sinkholes, contaminating olm habitats, or in India, where it’s common practice to use chemicals to disinfect wells.
BARTON SPRINGS POOL
IN SOME CASES, legislation and lawsuits have forced the preservation of at least some stygofauna. Barton Springs Pool is a deep, cold, spring-fed recreational pool near downtown Austin and has been a popular swimming venue for more than a century. (Long before the pool was built up, the springs themselves were used by Indigenous people). For some of that time, the city kept the natural pool in welcoming conditions for human visitors using intensive cleaning methods like hot water, high-pressure hoses, and chlorine.
But humans aren’t the only creatures there—deep in the springs that feed the pool live two different salamander species: the Barton Springs salamander, officially named in 1993, and the Austin blind salamander, discovered in 2001.
In 1992, the citizens of Austin passed an ordinance that restricted development in the recharge zones and limited pollution in the springs. That year, the city also stopped using chlorine to control algae at the pool. After the federal government listed the Barton Springs salamander as endangered in accordance with the Endangered Species Act in 1997, other practices were changed to protect the salamanders. Today, as part of an agreement with the US Fish and Wildlife Service, the city can still use the pool for swimming and can clean it (though with less destructive methods: High-pressure washing in salamander habitats is banned, and dropping the water level for cleaning is restricted). But in return, the city also has to help protect the ecosystem.
SALAMANDER BREEDING PROGRAM
In 1998, as part of that protection, Austin launched a captive breeding program for the salamanders. Now a captive population of about 240 Barton Springs salamanders and about 50 Austin blind salamanders live inside a small facility a few minutes from the springs.
“Our whole goal, and it’s a pretty standard goal for captive breeding programs, is to maintain 90 percent gene diversity for a hundred years,” said Dee Ann Chamberlain, an environmental scientist and the head of the program.
In addition to allowing for the study of the animals, the program also provides a failsafe in case of disaster. Barton Springs depends on water that enters the aquifer and flows in from the surface through nearby areas called recharge zones. A nearby chemical spill from, say, a crashed tanker truck or industrial accident could spell disaster for the salamanders.
“You could have a contaminant spill reach the springs in about a day,” said Chamberlain. “So there’s very real threats to the species.”
In that case, Chamberlain and her team would scoop up as many of the rare creatures from the wild as possible to bring back to the center before the contamination arrived. One day, when it was deemed safe, the scientists say they would return the salamanders’ babies to the springs.
PROTECTING RECHARGE ZONES
Of course, protecting these zones from contamination would be better than trying to fix things after the fact. To that end, Austin has purchased land in the recharge zones and plans to purchase more, said Scott Hiers, a geoscientist employed by the city. This will limit development in those areas, he added, helping reduce the risk of pollution and ensuring surface water can trickle down to the aquifer.
“The land protection strategy is sort of the gold standard in my mind,” said Devitt. “The ultimate goal is to protect and preserve the watersheds that support these species.”
Development has also been stymied by lawsuits, such as one filed by the Center for Biological Diversity in 2019 alleging that highway construction could threaten Austin’s salamanders. The Endangered Species Act has also resulted in restrictions on groundwater usage in Texas.
Other parts of the world have also made efforts to protect stygofauna: The Western Australian government, for instance, has required that the subterranean fauna be considered in environmental assessments since the mid-1990s, and in India, new fees and stricter laws around groundwater use may provide additional protection, though conservationists have said more will need to be done.
But pressures on the ecosystems still remain.
“So not to paint a very bleak picture, but I think that it’s certainly going to be very challenging moving forward to keep some of these populations, if not species, from going extinct,” said Devitt. “That’s just the reality of it. I mean, one of the most recent species we discovered was right in the middle of a small city that’s only getting bigger. Salamanders are amazing at persisting, but only to a point.”
Credit: 123rf.com
Texas must address groundwater future, says expert
By Jeff Falk, Rice University
June 11, 2021
Long-term water security is essential for the future of Texas, and the state acutely needs a common law system that can balance world-scale agricultural activity, industrial development and urban growth while also protecting private property rights, according to new research from Rice University's Baker Institute for Public Policy and Texas State University's The Meadows Center for Water and the Environment.
The analysis, authored by Gabriel Collins, the Baker Botts Fellow in Energy and Environmental Regulatory Affairs at the Baker Institute, aims to provide a foundation for such discussions.
"Water is an underappreciated and irreplaceable component of the Texas growth model," Collins wrote. "At the same time, significant droughts in the state are a question of 'when,' not 'if.' Water policy can certainly wait until a more sustained supply crunch emerges and then respond reactively. But it is far better to address a known risk in a proactive manner—one that builds in the time and space needed to craft solutions and create the legal, market and physical infrastructure needed to implement them over decades."
Texas groundwater common law is fundamentally based on principles developed in ancient Rome more than a millennium ago, Collins said. It has also been nearly 120 years since the state adopted the "rule of capture," which, as described by the Texas Supreme Court, "essentially allows, with some limited exceptions, a landowner to pump as much groundwater as the landowner chooses, without liability to neighbors who claim that the pumping has depleted their wells."
Since that landmark decision, Texas has grown into one of the largest economies and groundwater users in the world. Data from the United Nations Food and Agricultural Organization indicate that based on the 1997-2017 median extraction volume, Texas would be the world's 11th-largest groundwater pumper—extracting about 10 million acre-feet of water per year, or slightly less than what Turkey extracts and a bit more than Argentina. For perspective, 1 million acre-feet of water would cover the entire city of Houston roughly knee-deep.
Collins' report draws upon dozens of judicial and legislative decisions taken in 10 other American states that, at various points in the past 150 years, have transitioned from the rule of capture to another groundwater common law doctrine.
Arkansas, Arizona, California, Florida, Kansas, Michigan, Nebraska, New Hampshire, Ohio and Oklahoma offer a blend of unique and cross-jurisdictional insights that can provide an informed basis for policymakers in Texas, should they choose to update the state's groundwater common law, Collins said. In this group of 10 states, Ohio and Michigan offer especially relevant examples, because each of these states adopted groundwater law doctrines that emphasize an equitable balance between competing uses while still respecting water owners' property rights, he said.
Two of the most serious groundwater management challenges Texas faces are the rule of capture's tendency to create a "tragedy of the commons" and the fact that the rule of capture is interspersed with a largely patchwork groundwater conservation district system that, with a few exceptions, diverges from hydrologic realities, Collins said.
"Dealing effectively with the first issue by updating Texas' groundwater common law could help alleviate broad pressures on groundwater resources in key areas and, in doing so, potentially mitigates the most distortionary aspects of the current groundwater conservation district system," he wrote. "Groundwater common law reform thus reshapes the environment in a way that addresses acute issues posed by unrestrained extraction in areas not covered by groundwater conservation districts, especially those where a restrictive district borders an ungoverned space whose denizens can overpump at the expense of property owners within district boundaries."
June 11, 2021
Long-term water security is essential for the future of Texas, and the state acutely needs a common law system that can balance world-scale agricultural activity, industrial development and urban growth while also protecting private property rights, according to new research from Rice University's Baker Institute for Public Policy and Texas State University's The Meadows Center for Water and the Environment.
The analysis, authored by Gabriel Collins, the Baker Botts Fellow in Energy and Environmental Regulatory Affairs at the Baker Institute, aims to provide a foundation for such discussions.
"Water is an underappreciated and irreplaceable component of the Texas growth model," Collins wrote. "At the same time, significant droughts in the state are a question of 'when,' not 'if.' Water policy can certainly wait until a more sustained supply crunch emerges and then respond reactively. But it is far better to address a known risk in a proactive manner—one that builds in the time and space needed to craft solutions and create the legal, market and physical infrastructure needed to implement them over decades."
Texas groundwater common law is fundamentally based on principles developed in ancient Rome more than a millennium ago, Collins said. It has also been nearly 120 years since the state adopted the "rule of capture," which, as described by the Texas Supreme Court, "essentially allows, with some limited exceptions, a landowner to pump as much groundwater as the landowner chooses, without liability to neighbors who claim that the pumping has depleted their wells."
Since that landmark decision, Texas has grown into one of the largest economies and groundwater users in the world. Data from the United Nations Food and Agricultural Organization indicate that based on the 1997-2017 median extraction volume, Texas would be the world's 11th-largest groundwater pumper—extracting about 10 million acre-feet of water per year, or slightly less than what Turkey extracts and a bit more than Argentina. For perspective, 1 million acre-feet of water would cover the entire city of Houston roughly knee-deep.
Collins' report draws upon dozens of judicial and legislative decisions taken in 10 other American states that, at various points in the past 150 years, have transitioned from the rule of capture to another groundwater common law doctrine.
Arkansas, Arizona, California, Florida, Kansas, Michigan, Nebraska, New Hampshire, Ohio and Oklahoma offer a blend of unique and cross-jurisdictional insights that can provide an informed basis for policymakers in Texas, should they choose to update the state's groundwater common law, Collins said. In this group of 10 states, Ohio and Michigan offer especially relevant examples, because each of these states adopted groundwater law doctrines that emphasize an equitable balance between competing uses while still respecting water owners' property rights, he said.
Two of the most serious groundwater management challenges Texas faces are the rule of capture's tendency to create a "tragedy of the commons" and the fact that the rule of capture is interspersed with a largely patchwork groundwater conservation district system that, with a few exceptions, diverges from hydrologic realities, Collins said.
"Dealing effectively with the first issue by updating Texas' groundwater common law could help alleviate broad pressures on groundwater resources in key areas and, in doing so, potentially mitigates the most distortionary aspects of the current groundwater conservation district system," he wrote. "Groundwater common law reform thus reshapes the environment in a way that addresses acute issues posed by unrestrained extraction in areas not covered by groundwater conservation districts, especially those where a restrictive district borders an ungoverned space whose denizens can overpump at the expense of property owners within district boundaries."
Little Arkansas Spring flowing into the Blanco River. Photo by Charles Kruvand
The basics of groundwater law in Texas
Groundwater is water that is found beneath the surface of the earth. The rock, sand or soil formations where the groundwater is found are known as aquifers. Where aquifers meet the earth’s surface, they are either recharged with water from the surface or release groundwater through springs.
GROUNDWATER LAW IN TEXAS
Texas’ guiding principle for groundwater management has been the rule of capture. Adopted in a 1904 court ruling, this rule gives the landowner the right to capture an unlimited amount of groundwater by tapping into the underlying aquifer.
With only a couple of limited exceptions, the landowner is not liable for injury to another adjacent landowner caused by excessive pumping, as long as the injury is not intentional. For this reason, the rule of capture is often referred to as the law of the biggest pump.
Our historical approach has been to limit any regulatory control of groundwater pumping. This practice appears to have been adequate when neighboring landowners were withdrawing similar, limited amounts of water, or they were not pumping enough to significantly affect each other’s ability to withdraw groundwater. However, with today’s increased demands on groundwater, the rule of capture is no longer sufficient to protect this limited water supply
Texas’ guiding principle for groundwater management has been the rule of capture. Adopted in a 1904 court ruling, this rule gives the landowner the right to capture an unlimited amount of groundwater by tapping into the underlying aquifer.
With only a couple of limited exceptions, the landowner is not liable for injury to another adjacent landowner caused by excessive pumping, as long as the injury is not intentional. For this reason, the rule of capture is often referred to as the law of the biggest pump.
Our historical approach has been to limit any regulatory control of groundwater pumping. This practice appears to have been adequate when neighboring landowners were withdrawing similar, limited amounts of water, or they were not pumping enough to significantly affect each other’s ability to withdraw groundwater. However, with today’s increased demands on groundwater, the rule of capture is no longer sufficient to protect this limited water supply
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Groundwater Conservation Districts (GCDs) in many areas of the state have the ability to modify the rule of capture to varying degrees. These districts are essential to the protection of groundwater resources because, in their absence, there is little ability to avoid the overexploitation of aquifers.
These districts have been Texas’ preferred management tool for groundwater resources since the 1950s, although the number of districts has grown over time. GCDs have the authority to regulate spacing and production of wells to ensure the availability of groundwater within the district’s boundaries, and, within certain limits, they can deny a permit to withdraw groundwater based on the effect it may have on aquifer conditions. The districts can require a permit amendment and charge a fee for the exportation of water, but they cannot deny a permit based on the groundwater’s destination nor can they adopt rules to limit exports. At present, GCDs can only regulate large groundwater withdrawals. Withdrawals under 25,000 gallons a day from a well located on 10 acres or more generally remain exempt. The recent explosion of exempt wells, particularly in the Hill Country, has heightened concern about the potential impact on local aquifers. As of April 2013, there were 99 groundwater districts in Texas covering all or part of 144 counties. Many areas of the state are not included within groundwater district boundaries and therefore have no groundwater management, including some high growth areas of the state, such as southwestern Travis County and Western Comal County. The Texas Water Development Board website provides a downloadable map of Texas groundwater districts. |
Windmill at Big Bend Ranch. Photo courtesy of TPWD
THE FUTURE OF TEXAS GROUNDWATER
To enable more efficient coordination between groundwater districts that manage shared aquifers, the Texas Legislature created the Groundwater Management Area Process in 2005. Click here to learn more about the Texas Groundwater Management Area Process. Recently, the ability of GCDs to limit groundwater pumping to protect aquifer resources has been challenged. In 2012, the Texas Supreme Court ruled that the landowner has a vested right to the water under their property, and that while it is permissible for Groundwater Conservation Districts to regulate the resource, excessive regulation may constitute a constitutional taking, requiring landowner compensation. A later August 2013 ruling by the Fourth Court of Appeals in San Antonio found that such regulation did constitute a constitutional taking, creating much uncertainty in the future management of groundwater in Texas. |
Groundwater Regulation for Private Well Owners
Explains how groundwater production and use is managed and regulated in Texas.
State law does not provide any state agency with the authority to regulate the use or production of groundwater. Groundwater production and use is managed and regulated by local or regional groundwater conservation districts (GCDs).
Areas that are not within a GCD are subject to the rule of capture that essentially provides that groundwater, once it has been captured by a well and produced to the surface, belongs to the landowner. Limitations to the rule of capture include:
State law does not provide any state agency with the authority to regulate the use or production of groundwater. Groundwater production and use is managed and regulated by local or regional groundwater conservation districts (GCDs).
Areas that are not within a GCD are subject to the rule of capture that essentially provides that groundwater, once it has been captured by a well and produced to the surface, belongs to the landowner. Limitations to the rule of capture include:
- capture and use of groundwater cannot be done maliciously with the purpose of injuring a neighbor or amount to willful waste of the resource
- a landowner is liable for damages if his negligent pumping of groundwater results in the subsidence of neighboring land (that is, lowering in elevation of the land surface caused by the withdrawal of groundwater).
Priority Groundwater Management Areas
Program to identify areas of Texas experiencing, or expected to experience, critical groundwater problems and encourage the creation of Groundwater Conservation Districts (GCDs) for those areas. Relevant reports, studies, maps, and rules.
PGMA INFORMATION
To enable effective management of the state's groundwater resources in areas where critical groundwater problems exist or may exist in the future, the Legislature has authorized TCEQ, the Texas Water Development Board (TWDB) , and the Texas Parks and Wildlife Department (TPWD) to study, identify, and delineate PGMAs and initiate the creation of GCDs within those areas, if necessary.
WHAT IS A PGMA?
A Priority Groundwater Management Area (PGMA) is an area designated and delineated by TCEQ that is experiencing, or is expected to experience, within 50 years, critical groundwater problems including shortages of surface water or groundwater, land subsidence resulting from groundwater withdrawal, or contamination of groundwater supplies.
Since the ultimate purpose of designating a PGMA is to ensure the management of groundwater in areas of the state with critical groundwater problems, a PGMA evaluation will consider the need for creating Groundwater Conservation Districts (GCDs, or "districts") and different options for doing so. Such districts are authorized to adopt policies, plans, and rules that can address critical groundwater problems.
If a study area is designated as a PGMA, TCEQ will make a specific recommendation on GCD creation. State law authorizes the citizens in the PGMA two years to establish a GCD. However, if local action is not taken in this time frame, TCEQ is required to establish a GCD that is consistent with the original recommendation. Under either scenario, the resultant GCD would be governed by a locally elected board of directors.
For more information about PGMAs, see Texas A&M AgriLife Extension Service publication B-6191, Priority Groundwater Management Areas: Overview and Frequently Asked Questions . A hard copy or free electronic download of this publication is available after setting up an account.
PGMA INFORMATION
To enable effective management of the state's groundwater resources in areas where critical groundwater problems exist or may exist in the future, the Legislature has authorized TCEQ, the Texas Water Development Board (TWDB) , and the Texas Parks and Wildlife Department (TPWD) to study, identify, and delineate PGMAs and initiate the creation of GCDs within those areas, if necessary.
- Map of Priority Groundwater Management Areas (PGMAs) and Aquifers (January 2018)
- TCEQ PGMA GIS data can be found on the agency's GIS Data Hub (click on the "Water" link under the "Explore Our Programs" heading).
- Summary Description of PGMAs (February 2023)
- An interactive, online map ("Viewer") is available that allows users to obtain spatial information about designated Priority Groundwater Management Areas (PGMAs) and created and confirmed Groundwater Conservation Districts (GCDs). See the User Guide for more information.
- Rules
- Legislative Reports (Since 1997)
- Studies, Study Areas, and Designated PGMAs
- PGMA Reports (Since 2004)
- GCD Recommendation Reports (Since 2008)
- GCDs Created in Designated PGMAs
WHAT IS A PGMA?
A Priority Groundwater Management Area (PGMA) is an area designated and delineated by TCEQ that is experiencing, or is expected to experience, within 50 years, critical groundwater problems including shortages of surface water or groundwater, land subsidence resulting from groundwater withdrawal, or contamination of groundwater supplies.
Since the ultimate purpose of designating a PGMA is to ensure the management of groundwater in areas of the state with critical groundwater problems, a PGMA evaluation will consider the need for creating Groundwater Conservation Districts (GCDs, or "districts") and different options for doing so. Such districts are authorized to adopt policies, plans, and rules that can address critical groundwater problems.
If a study area is designated as a PGMA, TCEQ will make a specific recommendation on GCD creation. State law authorizes the citizens in the PGMA two years to establish a GCD. However, if local action is not taken in this time frame, TCEQ is required to establish a GCD that is consistent with the original recommendation. Under either scenario, the resultant GCD would be governed by a locally elected board of directors.
For more information about PGMAs, see Texas A&M AgriLife Extension Service publication B-6191, Priority Groundwater Management Areas: Overview and Frequently Asked Questions . A hard copy or free electronic download of this publication is available after setting up an account.
Even though surface water has many useful applications, groundwater aquifers are able to provide the majority of the drinking water supply throughout the U.S. To understand how these types of water can be used, it’s important to look at the many differences between groundwater and surface water. This article goes into detail about what these differences are and how they can impact you.
GROUNDWATER VS SURFACE WATER QUALITY
The main difference between groundwater and surface water involves the water quality for each. As a result of air fallout and runoff, surface water can contain high amounts of contaminants, which means that the water will need to be treated extensively before it can be used as a community’s water supply. It’s common for surface water to be comprised of chemical pollutants that accumulate through runoff.
While groundwater is typically cleaner than surface water, it can still contain various contaminants. These contaminants are picked up from seepage and soil percolation. On the other hand, the sediment layers that are found below the water table can filter the water naturally to remove at least some of the contaminants. Since there are fewer contaminants in groundwater, this type of water requires less treatment before being used as drinking water.
Even though groundwater is the main source of water for drinking water supplies across the country, it’s important to understand that only some groundwater is easy to gain access to. Nearly 98 percent of all freshwater across the world is groundwater. However, an ample amount of this water is located very deep underground, which means that it’s expensive to pump the water.
Another reason that groundwater is oftentimes preferable over surface water is that groundwater is more accessible during a drought. When a drought occurs, most of the surface water can dry up, which can create issues for any industries that rely on surface water as their primary water supply. Because groundwater typically contains fewer contaminants than surface water, it’s less expensive and easier to treat. While surface waters are commonly found in streams and lakes, groundwater can be accessed in wells wherever the water is needed, which makes it easier to get to.
Even though groundwater is mainly used to supplement drinking water supplies, there are several notable applications that it can be used for. Geothermal energy is able to tap into groundwater to create highly energy-efficient HVAC systems. A number of large facilities have started using groundwater for the purpose of heating and cooling their buildings.
Despite the many advantages that come with using groundwater, there are some issues that you should be aware of, the primary of which involves the population size of a given area. When the population in an area begins to rise, the amount of pollution will also increase. Higher pollution causes more pressure to be placed on groundwater. Even though sources of groundwater are able to provide more water when compared to surface water sources, it takes longer for groundwater aquifers to fill up after they’ve been tapped.
HOW IS GROUNDWATER CONTAMINATED?
GROUNDWATER VS SURFACE WATER QUALITY
The main difference between groundwater and surface water involves the water quality for each. As a result of air fallout and runoff, surface water can contain high amounts of contaminants, which means that the water will need to be treated extensively before it can be used as a community’s water supply. It’s common for surface water to be comprised of chemical pollutants that accumulate through runoff.
While groundwater is typically cleaner than surface water, it can still contain various contaminants. These contaminants are picked up from seepage and soil percolation. On the other hand, the sediment layers that are found below the water table can filter the water naturally to remove at least some of the contaminants. Since there are fewer contaminants in groundwater, this type of water requires less treatment before being used as drinking water.
Even though groundwater is the main source of water for drinking water supplies across the country, it’s important to understand that only some groundwater is easy to gain access to. Nearly 98 percent of all freshwater across the world is groundwater. However, an ample amount of this water is located very deep underground, which means that it’s expensive to pump the water.
Another reason that groundwater is oftentimes preferable over surface water is that groundwater is more accessible during a drought. When a drought occurs, most of the surface water can dry up, which can create issues for any industries that rely on surface water as their primary water supply. Because groundwater typically contains fewer contaminants than surface water, it’s less expensive and easier to treat. While surface waters are commonly found in streams and lakes, groundwater can be accessed in wells wherever the water is needed, which makes it easier to get to.
Even though groundwater is mainly used to supplement drinking water supplies, there are several notable applications that it can be used for. Geothermal energy is able to tap into groundwater to create highly energy-efficient HVAC systems. A number of large facilities have started using groundwater for the purpose of heating and cooling their buildings.
Despite the many advantages that come with using groundwater, there are some issues that you should be aware of, the primary of which involves the population size of a given area. When the population in an area begins to rise, the amount of pollution will also increase. Higher pollution causes more pressure to be placed on groundwater. Even though sources of groundwater are able to provide more water when compared to surface water sources, it takes longer for groundwater aquifers to fill up after they’ve been tapped.
HOW IS GROUNDWATER CONTAMINATED?
Even though groundwater tends to contain fewer contaminants than surface water, there are several ways that groundwater can become contaminated, which you should be aware of before treating this water. Groundwater pollution mainly occurs when contaminants are leached from, discharged to, or deposited on the land surface that’s situated above the groundwater. While the presence of domestic and industrial pollution sources in the general vicinity of the groundwater will dictate how contaminated the water is, this water can still contain some contaminants even if there are no nearby pollution sources.
If you want to use groundwater for drinking water, it’s essential that you take the time to test the water. Even small chemical concentrations can cause an individual to become sick. One contaminant that’s found in relatively high concentrations of groundwater is arsenic. Testing the groundwater before consumption is the only way to determine if contaminants like arsenic are currently present in the water. Additional contaminants like manganese, iron, dissolved organic material, and salt are found in high levels in different groundwater sources.
The pollution in groundwater can come from two separate sources, which include point and non-point sources. Point sources refer to any localized and identifiable pollution sources, which can include accident spills, septic systems, landfills, industrial sources, and gasoline storage tanks. All of these sources can contaminate groundwater. As for non-point sources, these typically get into groundwater through the use of chemicals and road salts. Agricultural operations may also act as non-point sources. For instance, pesticides are considered to be a primary non-point source of groundwater pollution.
When looking specifically at landfills, they are able to contaminate groundwater as a result of chemical leach being sent downwards and into the ground. While some landfills are equipped with bottom layers that effectively prevent leaching, other landfills either go without a protective layer or have an older layer that has become cracked and ineffective over the years. Across the U.S., it’s believed that there are over 10 million storage tanks that are buried in the ground, many of which contain oil, gasoline, and other chemicals. Over time, corrosion weakens the steel enclosure and causes cracks to form, which results in the chemicals entering the groundwater.
When a septic system has been poorly constructed or designed, harmful chemicals, bacteria, and viruses can get into the groundwater, which further contaminates the water to the point that treatment is necessary. At the moment, there are over 20,000 hazardous waste sites in the U.S. that are either uncontrolled or abandoned entirely. The worst aspect of hazardous waste is that it contains chemicals that aren’t commonly tested for by municipalities and cities. In the event that an accidental spill or septic system leak contaminates the groundwater, this water would likely be costly to treat.
MINERALS IN WATER
If you want to use groundwater for drinking water, it’s essential that you take the time to test the water. Even small chemical concentrations can cause an individual to become sick. One contaminant that’s found in relatively high concentrations of groundwater is arsenic. Testing the groundwater before consumption is the only way to determine if contaminants like arsenic are currently present in the water. Additional contaminants like manganese, iron, dissolved organic material, and salt are found in high levels in different groundwater sources.
The pollution in groundwater can come from two separate sources, which include point and non-point sources. Point sources refer to any localized and identifiable pollution sources, which can include accident spills, septic systems, landfills, industrial sources, and gasoline storage tanks. All of these sources can contaminate groundwater. As for non-point sources, these typically get into groundwater through the use of chemicals and road salts. Agricultural operations may also act as non-point sources. For instance, pesticides are considered to be a primary non-point source of groundwater pollution.
When looking specifically at landfills, they are able to contaminate groundwater as a result of chemical leach being sent downwards and into the ground. While some landfills are equipped with bottom layers that effectively prevent leaching, other landfills either go without a protective layer or have an older layer that has become cracked and ineffective over the years. Across the U.S., it’s believed that there are over 10 million storage tanks that are buried in the ground, many of which contain oil, gasoline, and other chemicals. Over time, corrosion weakens the steel enclosure and causes cracks to form, which results in the chemicals entering the groundwater.
When a septic system has been poorly constructed or designed, harmful chemicals, bacteria, and viruses can get into the groundwater, which further contaminates the water to the point that treatment is necessary. At the moment, there are over 20,000 hazardous waste sites in the U.S. that are either uncontrolled or abandoned entirely. The worst aspect of hazardous waste is that it contains chemicals that aren’t commonly tested for by municipalities and cities. In the event that an accidental spill or septic system leak contaminates the groundwater, this water would likely be costly to treat.
MINERALS IN WATER
Groundwater is commonly contaminated as a result of water dissolving the substances it comes into contact with. In fact, water directly dissolves more substances than all other liquids. When mineral content gets into a water supply, the water may be referred to as hard water. Hard water consists of high amounts of ions like magnesium and calcium. In comparison, soft water contains a small or nonexistent amount of minerals.
To measure the hardness of water, the magnesium and calcium concentrations will be identified before being converted to calcium carbonate. This measurement is displayed in milligrams per liter. In accordance with the United States Geological Survey, water is divided into four categories that are centered around the water’s mineral concentrations.
These categories include:
Keep in mind that water hardness can also be measured by grains per gallon, which is common in the water treatment industry. When using this type of measurement, water hardness is divided into five categories:
Water hardness is an essential measurement for many industries as it demonstrates how clean the water is. Hard water can be highly damaging to many of the systems and components that are found in an industrial setting. The same is true if the water that runs through your home has a high concentration of minerals. If you don’t soften the water with some type of water softener, limescale deposits could develop in plumbing fixtures, showerheads, and faucets, which would invariably worsen water flow and make your appliances less efficient.
While both groundwater and surface water has numerous applications that they can be used for, groundwater is in abundant supply across nearly every area of the country, which makes it easier to access. Despite the lower concentration of contaminants in groundwater, it’s important that any groundwater you use is measured and treated before use. By taking these precautions, you can remove contaminants and effectively purify the water.
To measure the hardness of water, the magnesium and calcium concentrations will be identified before being converted to calcium carbonate. This measurement is displayed in milligrams per liter. In accordance with the United States Geological Survey, water is divided into four categories that are centered around the water’s mineral concentrations.
These categories include:
- Soft water – Anything between 0-60 mg/L
- Moderately hard water – Anything between 61-120 mg/L
- Hard water – Anything between 121-180 mg/L
- Very hard water – Anything above 180 mg/L
Keep in mind that water hardness can also be measured by grains per gallon, which is common in the water treatment industry. When using this type of measurement, water hardness is divided into five categories:
- Soft water – Anything from 0.0-1.0 gpg
- Slightly hard water – Anything from 1.1-3.5 gpg
- Moderately hard water – Anything from 3.6-7.0 gpg
- Hard water – Anything from 7.1-10.5 gpg
- Extremely hard water – Anything above 10.5 gpg
Water hardness is an essential measurement for many industries as it demonstrates how clean the water is. Hard water can be highly damaging to many of the systems and components that are found in an industrial setting. The same is true if the water that runs through your home has a high concentration of minerals. If you don’t soften the water with some type of water softener, limescale deposits could develop in plumbing fixtures, showerheads, and faucets, which would invariably worsen water flow and make your appliances less efficient.
While both groundwater and surface water has numerous applications that they can be used for, groundwater is in abundant supply across nearly every area of the country, which makes it easier to access. Despite the lower concentration of contaminants in groundwater, it’s important that any groundwater you use is measured and treated before use. By taking these precautions, you can remove contaminants and effectively purify the water.
