Author: getwetprojectblog

A study into the management and attitudes of key stakeholders operating in the Great Barrier Reef region has found that past and current approaches do not adequately address climate change threats to the reef or likely losses of species, habitats and processes.

Dr. Wade Hadwen from Griffith University’s Australian Rivers Institute and Climate Action Beacon and Lisa Walpole from Alluvium Consulting published the results in Ecology and Society. 

The study provides a critical evaluation of management plans and actions with respect to the Great Barrier Reef over the past 30 years, focusing on the degree to which climate change threats have been incorporated into those plans and actions. 

With another mass bleaching event impacting the Great Barrier Reef and a United Nations push to list the reef as ‘in danger,” Dr. Hadwen said current management approaches fell short of what was needed to provide the reef with any chance of remaining in good condition. 

“In this study, we were able to review the management plans of key stakeholders in the GBR region and explore evidence of the willingness to accept environmental change—and the scientific evidence which has been talking about climate threats for almost five decades—through the lenses of environmental grief and resilience thinking concepts,” he said. 

“Despite the huge ongoing investment in reef protection, few components of the reef management program have fully incorporated climate change and recognized that changes in the ecosystem are occurring now and are inevitable. 

“This analysis highlights how the strategic planning environment for the GBR is lagging behind the state of knowledge.” 

The researchers found that management efforts for the GBR had focused on “resilience as recovery” and fell short of “resilience as adaptation” and the opportunities created by “resilience as transformation.” 

Despite the state of scientific understanding, Dr. Hadwen said the study revealed how the prevailing individual or collective mindset could support or suppress a “resilience as transformation” approach to management of the GBR. 

“Over the past five years, the GBR has been exposed to several unprecedented climate-related events, including three coral bleaching events and impacts from severe tropical cyclones, poor water quality from catchment run-off, population increaseand urbanization, port expansion, fishing, and habitat loss,” he said. 

“Acceptance of a future change in state in terms of system structure and function, and related changes in environmental, social, and economic values, would lead to a significant shift in the way the GBR is managed, liberating agencies and stakeholders to let go of the past and plan for the future.” 

The study, “Extreme events, loss, and grief—an evaluation of the evolving management of climate change threats on the Great Barrier Reef,” has been published in Ecology and Society.

FOR MORE INFORMATION: https://phys.org/news/2022-05-great-barrier-reef-methods-odds.html

Biologists at the University of Cincinnati are studying low-cost ways to improve water quality and wildlife habitat in urban creeks.

Like those found in many large cities, Cincinnati’s streams are routinely affected by flash floods, sewage overflows, pollution and stormwater runoff.

UC biologists Stephen Matter and Michael Booth are examining whether water quality and wildlife habitat can be improved simply by adding a touch more of Mother Nature. With a team of volunteers, they placed fallen logs and branches in select parts of the upper Cooper Creek, a stream in the Cincinnati suburb of Blue Ash that drains downstream into the larger Mill Creek and Ohio River.

The addition of fallen timber could help slow periodic floodwaters, create more standing pools for fish during droughts and reduce nutrients that could make their way downstream, researchers said.

“Cooper Creek typifies a lot of issues streams in Hamilton County face,” said Booth, an assistant professor who studies fish and aquatic ecology across the country.

“We know wood plays an important role for creating wildlife habitat. Cooper Creek is a boring place—lots of rocks but not much else,” he said. “In creeks you’d like to see a variety of habitats, fallen logs, standing pools and flowing water.”

The UC researchers presented the project in April to the Geological Society of America’s sectional conference in Cincinnati. The project is supported by the Ohio Water Resources Center through a U.S. Geological Survey grant.

Greater Cincinnati has an extensive network of creeks feeding its major rivers.

“These streams really are the lifeblood of the natural system,” said Matter, an associate professor of biology in UC’s College of Arts and Sciences.

“Most of our creeks are these small headwater streams. If you walk through Cincinnati, you’re going to run into one of these in every neighborhood,” Matter said. “Often they’re places we’d like to see nature.”

“There are lots of impervious surfaces. When it rains, you see a massive increase in stream flow. This leads to major changes in sediment and habitat available for aquatic life,” Booth said.

As a result, while Ohio is home to 170 native freshwater fish, the upper section of Cooper Creek is home to just three species of fish today, Booth said.

“As we go downstream, we might add four or five more species,” he said. That’s a startling lack of biodiversity and a sign of an unhealthy ecosystem, he said.

“But we would definitely expect to see double the number of fish species if we had better habitat and better connectivity for fish to move back up into these sections,” Booth said. “We’re looking for a cost-effective solution to deploy to improve urban streams.”

Adam Lehmann, stream conservation program manager for the Hamilton County Conservation District, is overseeing the demonstration project. He said the biggest challenge facing headwater streams in Ohio is they become bone dry between rainstorms.

“If a stream goes dry between rain events, the fish aren’t going to care how polluted the water is,” Lehmann said.

But by placing heavy logs in strategic places in the creek where flooding won’t easily be able to wash them downstream, Lehmann said he hopes to use the rush of water to his advantage to create intermittent pools of water where fish and other aquatic life can survive between storms.

“Everybody understands that when a stream goes dry, fish are out of luck,” he said. “If we jam one side of a log against a tree, we can force the flow of water under the log to scour out a depression that will hold water in dry times.”

Lehmann said the logs should help to catch other flood-swept debris as well. Historically, fallen timber was removed from creeks to prevent it from clogging drainage culverts. Paradoxically, Lehmann said they expect to see less woody debris blocking drainage culverts by adding more heavy wood to the creek.

Restoring the natural hydrology of creeks can be expensive and labor-intensive, often requiring intrusive heavy equipment. Researchers are hoping to see similar benefits from less drastic efforts than bringing in backhoes.

“I like to focus on scalable solutions,” Lehmann said. “You don’t have to mow down the forest to get in there. You don’t need to hire engineers or obtain Clean Water Act permits. And the wood is available free of charge.”

To gauge the project’s effectiveness, researchers plan to add little passive transponders to each log and return to see if the wood gets washed downstream or remains in place as they hope it will.

If the project is successful, it could demonstrate that relatively simple efforts can have profound benefits. Hamilton County is home to more than 1,000 headwater streams that feed its lakes and rivers, said Amanda Nurre, watershed specialist with the Great Parks of Hamilton County.

“We have a very impressive watershed in Hamilton County. There are small streams in every park. We’re very interested in finding low-cost ways to improve our streams. I think it could be a useful tool,” she said. “I’m optimistic to see if it can work.”

FOR MORE INFORMATION: https://phys.org/news/2022-05-biologists-low-cost-ways-urban-streams.html

“When it rains, it pours.” This phrase is meant to mean that bad news comes in waves. Unfortunately, that’s true with real rain, too. While rain is usually welcome for various reasons, in developed area like cities and towns, it can produce a big problem: polluted runoff.

Wherever rains lands on traditional human-made surfaces, it can’t soak into the ground. Instead, water from large areas like streets, driveways, and roofs collects, looking for lower ground. To deal with this runoff, cities have developed complex stormwater control systems. Eventually, the water is routed to a stream or lake. This runoff, though, can become contaminated in its travels, which risks the pollution of essential waterways.

In addition to hurting waterways, none of the runoff water helps recharge groundwater. Because many people rely on groundwater for drinking water, this can become a big problem. This is where green infrastructure practices come in. These structures collect stormwater and let it soak into the soil naturally. Bioretention cells are a popular example of green infrastructure for improving stormwater at a large scale, and rain gardens on a residential scale.

“The first goal of green stormwater infrastructure measures is to allow stormwater to filter into the ground on-site so that it contributes to groundwater recharge,” says Thorsten Knappenberger, a professor at Auburn University. Knappenberger recently conducted a study on how to make these structures better.

The study was published in Agricultural & Environmental Letters, a publication of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

The study focused on two main ways to try and improve bioretention cells. One was to ensure water soaks into the soil at an optimum rate to treat pollutants. The other focus was to increase how many pollutants the cell can trap. Excess nutrients from fertilizer and heavy metals are especially worrisome when they runoff into water bodies. These contaminants decrease water quality, which is a big issue for surface water and groundwater that people drink. If a cell can hold onto and transform these contaminates, it protects water quality.To try and improve these metrics, Knappenberger tested a material known as zeolite. This mineral is made of aluminum and silicon that traps toxic chemicals. Knappenberger replaced some of the sand in the rain gardens with zeolite and measured how well the material performed.

Not surprisingly, zeolite held onto contaminates like ammonia and copper. But because the existing formula for bioretention cells is already efficient at trapping these materials, zeolite didn’t make a significant improvement. Zeolite also reduced the amount of nitrate leaving the cells. “Nitrate is a compound that is not typically held or retained by soil, so it was surprising that the nitrate retention was higher with added zeolite,” says Knappenberger. At the same time, zeolite tended to increase how quickly water could soak into the ground, which is a big plus. The findings could help communities design more effective bioretention cells.

While scientists like Knappenberger work to make green infrastructure practices better, readers may wonder what they can do to help. Be mindful about what is flushed down the storm drain, he says.

“Many people still think that the stormwater which enters a storm drain is treated in a wastewater treatment plant. But for the vast majority, the stormwater goes directly into a surface water body,” says Knappenberger. “This means that if you wash your car in your driveway, for example, the contaminated waterwith soap, oil, and grease will drain into a storm drain and might end up in the next creek.”

FOR MORE INFORMATION: https://phys.org/news/2022-05-helping-rain-stay-where-it.html

Griffith University researchers are unraveling how stressors like climate change, pollution, dissolved nitrogen and sediment from run-off are having combined effects in coastal ecosystems.

Two studies published in Ecology Letters and Proceedings of the Royal Society B reveal combining increasing ocean temperatures, pollution or dissolved nitrogen with the reduced light caused by sediment in the water can either amplify or reduce the impact of these stressors individually on seagrass or algal growth.

“Crucially, we show that the combined effects on seagrass and algal growth can vary significantly dependent on the amount of the two stressors and duration of exposure,” said Dr. Mischa Turschwell, Research Fellow at the Australian Rivers Institute.

“With the onset of climate change, coastal and marine ecosystems are under threat on more than one front from stressors such as rising ocean temperatures, poor water qualityand pollution.

“To effectively look after these coastal ecosystems, managers need a thorough understanding of the effects these human induced changes have, both individually and in combination.”

Associate Professor Chris Brown, head of the Seascape Models group at Australian Rivers Institute and the Coastal and Marine Research Centre lamented that “to-date most attempts to discover of how such stressors interact, using data pooled from multiple studies, have failed to find consistent predictions for combined effects.”

“Few generalities for the combined effects of these stressors have been seen, with meta-studies based on multiple pasts studies on same stressors often yielding conflicting results.”

With far too many potential stressor combinations for researchers to ever to hope to measure them all, accurate models are needed that can predict how potential environmental stressors interact.

Dr. Turschwell and his team built a model to predict how temperature and light interact to affect seagrass photosynthesis and growth, which also included an animal that consumed the seagrass.

“Using the model, we assessed the combined effect of both the temperature and the light in the water, altering the amount of both and how long they were exposed for,” Dr. Turschwell said.

“Surprisingly, our model revealed how combining the same two stressors could amplify or mitigate their individual consequences for seagrass growth.

“The combined impact on seagrass relied heavily on the changing amounts of the stressors. For example, when higher levels of light loss were combined with temperature the interactive impact became stronger.

“When organisms that eat seagrass were added to the model to better simulate real life systems the combined effect temperature and loss of light on seagrass growth changed yet again.”

To determine if these models are a true indication of what happens when water quality stressors are combined, Ph.D. candidate Olivia King conducted experimental studies on the interactive effects of three common stressors; a herbicide (diuron), dissolved inorganic nitrogen and reduced light (due to sediment).

Pollution in coastal water, such as herbicides in runoff from agriculture and sediment from erosion can affect the growth of important algae species.

Similar to finds using the model, Ms King’s study of multiple stressors like diuron and reduced light could either amplify or reduce their individual effects, depending on the changing amounts of these pollutants, how long they’re exposed or the biological response being looked at.

“This research clearly shows why it has been so difficult in the past to get a clear picture of how more than one stressor interact, because their combined effect can vary with factors like duration and the amount used.”

“To develop consistent patterns of these interactions we need to learn how stressors change with context and develop experiments accordingly that run over extended time scales, with treatments across gradients of stressor levels.”

There is an urgent need to better understand the combined impact of the multiple simultaneous stressors affecting the marine environment, in order to provide useful predictions on the highest priority stressors for managers of marine ecosystems to tackle.

“Water quality on the great barrier reef, for example, is managed using guidelines that currently only consider one pollutant at a time,” Associate Professor Brown said.

“Our work shows the need, and process for, updating water quality guidelines for the Great Barrier Reef and other important ecosystems, to account for the amplifying effects of multiple pollutants.

“Similarly, the combined effects of pollutants and increasing warming is a clear indication that water quality guidelines need to consider how increasing levels of climate change will interact with pollution.”

FOR MORE INFORMATION: https://phys.org/news/2022-05-unraveling-climate-pollution-runoff-combine.html

Mountain spring water is often touted as the cleanest water you can drink. But a new study from the University of Georgia revealed this isn’t the case.

Using data collected over 40 years, researchers detailed how water quality in high-elevation streams has been negatively affected by a combination of historical events and modern changes, namely sediment from rural roads and agricultural runoff.

Unpaved roads are just one of several factors contributing to sediment runoff, said Rhett Jackson, a professor at UGA’s Warnell School of Forestry and Natural Resources and the paper’s lead author.

The paper was published earlier this month in the journal Bioscience.

“We had access to studies from 1976 to last year that encompassed both stream and terrestrial studies,” said Jackson, who worked with researchers from Virginia Tech, the University of Illinois, the University of Minnesota and the U.S. Forest Service to analyze streams in a mountainous portion of North Carolina adjacent to the Coweeta Long-Term Ecological Research Site.

When streams carry a lot of sediment, it makes it more difficult for animals to see food in the water, and it affects fish growth and disease resistance. Sediment also continues to flow downstream and into public water supplies, where it costs cities and towns more to filter.

“Some streams in Macon County have very high sediment concentrations, four times greater than found in forested streams,” added Jackson.

The cost of a view

It’s important to note that Appalachian water quality issues began more than 100 years ago, said Jackson, when European settlers fundamentally changed the balance of the land long inhabited by Native Americans.

“The landscape you see now isn’t what it was like in 1900—the early settlers logged everything,” said Jackson. For generations, native Cherokee Indians farmed the valleys of the Southern Appalachians and left the hillsides forested, for hunting and gathering. But the new settlers cut the forests and even tried to farm the hills, causing erosion and sediment to move into the streams. Today, stream beds continue to show evidence of sediment deposited more than a century ago, even as new sediment pushes through the waters.

Many years later, a new kind of development in the region created a different kind of land disturbance. For generations, residents considered the steep mountain slopes undevelopable. But the 1980s and ’90s brought a desire for mountain getaway homes with views.

By building homes on mountain ridges, he said, it created more land disturbance through carving out unpaved roads and cutting into hillsides, sometimes creating landslides.

“Roadside ditches and unpaved roads produce a lot of sediment, and their sediment production increases as roads get steeper and as gravel roads get more use,” said Jackson.

A typical southern Appalachian forest stream contains sediment amounts—calculated as total suspended solid concentration—of about 8 to 10 milligrams per liter. But in areas with both mountain and valley development, the researchers found sediment concentrations four to six times higher.

Agricultural issues

Farming also takes its toll. The studies researchers analyzed found many streams in the area to have high nutrient concentrations—particularly nitrate. When a stream flowing through a pasture loses its buffer of trees, it loses a natural protection against nutrient runoff.

Streams without shade also have higher water temperatures. In Appalachia, where mountain trout and other wildlife thrive in cold waters, even a few extra degrees in the summer can kill trout or reduce their competitiveness against warm water fish.

Jackson said about 40% of streams in the study area aren’t buffered. But through best-management practices and state and federal programs, landowners can find assistance and resources to reverse the damage. “On small streams, the actions of individual landowners matter a lot,” he said. “Sometimes, we see unusual streamside activities with substantial water quality effects.” For example, researchers found instances of streams diverted through animal enclosures or illicit discharge pipes without clear sources.

Even small steps, such as buffering runoff from a gravel road or planting trees near an open stream, can go a long way, Jackson said.

“Because the water in streams comes from the whole landscape, everything we see on the land has some effect on streams,” he said. “But streams are resilient, and as long as we intelligently modify our actions a little bit, we can farm and live near streams while protecting their water quality. Maintaining the quality of our landscape requires a little thought and work on our parts.”

Scientists have recently confirmed that the world’s lakes are rapidly losing oxygen. With a seven-year, whole-ecosystem study, a team of freshwater scientists at Virginia Tech has been one of the first to take the next step in asking: What does it mean for water quality that oxygen is declining globally?Sticky with sediment, the bottom waters of lakes are more than their deepest, darkest layer. They bury massive portions of the carbon, nitrogen, and phosphorus found in runoff rolling in from the land. As one of nature’s critical nutrient sinks, lakes earn their recognition as “sentinels” of their surroundings, said freshwater scientist Cayelan Carey.

“We think of lakes as sentinels because they truly integrate all of the changes that happen on land,” said Carey, an associate professor of biological sciences in the Virginia Tech College of Science and an affiliated scientist with the Fralin Life Sciences Institute. “Lakes do this really great job of receiving and processing all of this carbon, nitrogen, and phosphorus, preventing them from going downstream and reaching the ocean.”

But that work could be dismantled by anoxia, the loss of oxygenavailability, Carey’s team found in a study published this week in Global Change Biology. Dreaded by scientists for years and recently confirmed as widespread by data from hundreds of lakes, anoxia is sucking oxygen from the world’s fresh waters.

It’s a phenomenon linked to the warming of waters brought on by climate change and to excess pollutant runoff from land use. Warming waters diminish fresh water’s capacity to hold oxygen, while the breakdown of nutrients in runoff by freshwater microbes gobbles up oxygen.

In a seven-year field experiment that manipulated oxygen levelsin the bottom waters of a nearby reservoir, Carey’s team found that with anoxic conditions came effects they had expected: the sediments release a lot of nutrients and carbon. But they weren’t as prepared for the extent of the changes. They observed the lake going from a sink—which retains more nutrients and carbon than it exports—to a source of nutrients downstream, starting a cycle in which anoxia in one lake could beget anoxia in another.

“I had no expectation that there would be this much change in water chemistry,” Carey said. “And to see it consistently and to see it over the seven years of the study—the effect of anoxia was multiple orders of magnitude greater than what I originally predicted.”

FOR MORE INFORMATION: https://phys.org/news/2022-05-vicious-oxygen-loss-threatens-quality.html

ST. PETERSBURG, Fla. (AP) — More than 80 rescued Florida manatees are in rehabilitation centers across the U.S. as wildlife officials try to stem starvation deaths by the marine mammals because of poor water quality.

The latest numbers were released Wednesday by the Florida Fish and Wildlife Conservation Commission and U.S. Fish and Wildlife Service as part of an unprecedented effort to feed starving manatees and treat those in distress.

The state has provided about $1.2 million for the treatment effort, officials said, with the rest of the increasing costs borne by facilities such as the SeaWorld rescue program in Orlando. There are 13 such locations at aquariums and other facilities in Florida, Texas, Ohio, Puerto Rico and elsewhere.

“It’s a huge effort and they do a fantastic job,” said Terri Calleson of the U.S. Fish and Wildlife Service. “A lot of it is happening on their dime.”

Last year, more than 1,100 manatee deaths were recorded largely due to starvation, well above the typical five-year average of about 625 deaths. In 2022 through last week, 326 manatee deaths have been listed, only seven from collisions with boats, according to state wildlife commission statistics.

The experimental feeding program using romaine lettuce continues seven days a week at a Florida Power & Light plant in Brevard County along the east coast where hundreds of manatees typically gather in cold months in the plant’s warm water discharge area.

As of Tuesday, more than 63,000 pounds (28,500 kilograms) of lettuce has been provided to the manatees, said Jon Wallace of the U.S. Fish and Wildlife Service. The food is paid for mostly by donations to the non-profit Fish & Wildife Foundation of Florida.

“That is all still going very well,” Wallace said.

There are an estimated 8,800 or so manatees in Florida waters. That’s a big improvement from the roughly 2,000 animals in the 1990s, part of the reason they were delisted from endangered to threatened by the federal government.

Officials say it’s important for people in Florida’s coastal areas to report any sick or distressed manatees they see so they can be brought to a rehabilitation center.

“Overall, we view these rescue efforts as successful. This is a small victory for us,” said Andy Garrett, manatee rescue coordinator for the state wildlife commission.

But officials also stressed the approach of warmer weather does not mean the starvation problem is over, especially since some of the slow-moving, round-tailed animals will need extensive treatment.

“This need does not stop with the end of cold weather this year,” said Jon Peterson, rescue operations manager at SeaWorld. “Some of the animals have been here a long time. It does take time.”

FOR MORE INFORMATION: https://apnews.com/article/travel-environment-and-nature-florida-orlando-animals-bcce92347c22878bc36bd239ed55a6d3

As a worsening drought forces millions of Californians to face mandatory water restrictions, one corner of Southern California has largely shielded itself from supply-related woes: San Diego County. 

For Western water planners, the path it took to get there serves either as a blueprint or a cautionary tale.

Over the past three decades, San Diego County diversified its water supply, ramped up conservation and invested in big-ticket water infrastructure including the Western hemisphere’s largest desalination plant, which removes salt and impurities from ocean water. As a result, the water agency that serves 24 water utilities including the city of San Diego says it can avoid cuts until at least 2045, even during dry periods. But that security has come at a cost.

San Diego County’s water is among the most expensive in the country, costing about 26% more at the wholesale level in 2021 than the Metropolitan Water District’s, which serves Los Angeles and surrounding counties. Now, two rural irrigation districts in San Diego County home to large avocado industries want to break away from the regional water supplier, saying they can purchase cheaper water elsewhere. If they succeed, water in San Diego County could grow even more expensive.

“San Diego’s situation is very surprising, very striking,” said Michael Hanemann, an environmental economist at Arizona State University who recently was commissioned to study the region’s water costs for a California agency. “I think this is a harbinger of something that’s going to happen elsewhere in California and elsewhere in the U.S.” 

WHY SO EXPENSIVE

San Diegans didn’t always rest easy during drought. In the 1990s, a severe dry period cut the region’s water supply by 30%. At the time, almost all of its water came from the Metropolitan Water District, the country’s largest water provider. That experience and a tense, dysfunctional relationship — California water experts say — with water officials in Los Angeles spurred San Diego County’s aggressive, decades-long pursuit of water self-sufficiency.

“At that point, our community came together and said, ’We’re not going to be in this situation again. We need to plan for our own reliability,” said Sandy Kerl, general manager of the San Diego County Water Authority. 

So in 2003, the water authority cut a deal to get water from the single largest user of the Colorado River, the Imperial Irrigation District, in Southern California. San Diego County funded repairs to leaky canals belonging to Imperial and signed a historic water transfer deal. Today, it receives about 55% of its total supply from Imperial as part of the deal. 

The water authority also helped farmers use less water. It raised dams to increase storage capacity in reservoirs. It provided rebates to homeowners who ripped out grass lawns for water-efficient alternatives.

In 2012, San Diego County forged a deal to get 10% of its water supply from the Carlsbad Desalination Plant for the next 30 years. The plant produces 50 million gallons of drinkable water — enough for about 400,000 people — every day and is by far the region’s most expensive water source.

FOR MORE INFORMATION: https://apnews.com/article/california-droughts-environment-san-diego-81ab84fafe94a0c5c298ede24fd2f7f1

In southwestern Pennsylvania, eight locks and dams that for decades helped barges move goods along the Allegheny, Monongahela and Ohio rivers will in a few years also generate enough power for 75,000 homes.

Rye Development, a Boston-based hydropower company, is retrofitting the dams with turbines to generate electricity and says the upgraded structures will limit damage to the rivers’ water quality and fish.

The project reflects a recent thawing between the industry and conservation groups, which had long opposed dams that can prevent fish migration, alter water temperatures and cause other environmental problems. As the U.S. pushes to transition to low-carbon energy, Rye is among the companies that sees an opportunity to expand hydropower production at existing dams while working to minimize environmental harms.

The recent compromises between the industry and environmental groups are reflected in President Joe Biden’s infrastructure law, which puts $2.5 billion toward projects including dam removals as well as upgrades at existing structures for hydropower and energy storage.

Hydropower, which uses flowing water to spin turbines connected to generators, is the oldest and second-largest renewable energy source in the U.S. after wind power. In 2020, it accounted for roughly 7% of the electricity generated in the country.

The industry hasn’t received as much federal funding and tax incentives as wind and solar, but sees room for growth. Of the 90,000 dams in the country, about 2,500 produce power. Non-powered dams could produce enough power for 9 to 12 million homes, according to an estimate by the Electric Power Supply Association based on federal data from 2012.

Part of the challenge is that most dams in the U.S. were built more than half a century ago. The risk of dam collapses has fueled demolitions in recent years, with more than 40% of the country’s nearly 2,000 dam removals in the past century happening in the last decade. Some are also torn down largely for environmental reasons. 

Last month, federal regulators moved a step closer to approving what would be the largest dam demolition in U.S. history. Removal of the four hydroelectric dams on the Klamath River near the Oregon-California border would help save the river’s salmon and other fish species that can’t reach breeding habitat because of the structures.

The hydropower industry and conservation groups still clash over dams too. On Maine’s Kennebec River, conservation groups and state environmental agencies are pushing for the removal of four hydropower dams that block endangered Atlantic salmon from reaching key habitat. The dams generate about 5% of the state’s renewable energy.

“It’s very easy for individual river systems to get lost in the message of climate change and the need for renewable energy,” said Shannon Ames, executive director of the Low Impact Hydropower Institute, which grades hydropower dams based on environmental criteria.

With persisting drought affecting hydropower production west of the Mississippi River, the industry has a more direct path to expansion in eastern states. 

In Pennsylvania, Rye consulted with the Low Impact Hydropower Institute early in its process and is among a small number of companies seeking certification from the group. 

To get certified, companies must show their structures meet protections for endangered species, cultural and historic uses of rivers, passage for fish and recreational areas. The group says its environmental standards are often stricter than state or federal guidelines.

On a recently certified dam in West Virginia on the Ohio River, for example, dissolved oxygen levels — an important measure of river water quality — were meeting or exceeding state standards, according to a five-year study. In some states, dams certified by the organization qualify for green-energy programs.

Rye said its dams in Pennsylvania will include structures to support fish migration ,and that it is building a fishing pier since federal regulators require hydropower producers to support recreation on river systems. The retrofits are expected to be operational as early as 2025.

FOR MORE INFORMATION: https://apnews.com/article/biden-business-pennsylvania-environment-environment-7c024d8fd9edfab0e39bbfa82fcae699

The Safe Drinking Water Act defines the term “contaminant” as meaning any physical, chemical, biological, or radiological substance or matter in water. Therefore, the law defines “contaminant” very broadly as being anything other than water molecules. Drinking water may reasonably be expected to contain at least small amounts of some contaminants. Some drinking water contaminants may be harmful if consumed at certain levels in drinking water while others may be harmless. The presence of contaminants does not necessarily indicate that the water poses a health risk.

Only a small number of the universe of contaminants as defined above are listed on the Contaminant Candidate List (CCL). The CCL serves as the first level of evaluation for unregulated drinking water contaminants that may need further investigation of potential health effects and the levels at which they are found in drinking water.

Related Information

Learn about contaminants that are currently regulated

How EPA regulates drinking water contaminants

The following are general categories of drinking water contaminants and examples of each:

• Physical contaminants primarily impact the physical appearance or other physical properties of water. Examples of physical contaminants are sediment or organic material suspended in the water of lakes, rivers and streams from soil erosion.
• Chemical contaminants are elements or compounds. These contaminants may be naturally occurring or man-made. Examples of chemical contaminants include nitrogen, bleach, salts, pesticides, metals, toxins produced by bacteria, and human or animal drugs.
• Biological contaminants are organisms in water. They are also referred to as microbes or microbiological contaminants. Examples of biological or microbial contaminants include bacteria, viruses, protozoa, and parasites.
• Radiological contaminants are chemical elements with an unbalanced number of protons and neutrons resulting in unstable atoms that can emit ionizing radiation. Examples of radiological contaminants include cesium, plutonium and uranium.

FOR MORE INFORMATION: https://www.epa.gov/ccl/types-drinking-water-contaminants