Big Berkey Water Filters

  • EPA Funds Largest Citizen-Science Based Water Quality Research Project

    A grant from the US Environmental Protection Agency has given the engineering team from Virginia Tech who exposed the Flint water crisis the funding to allow them to conduct their detective work in other communities that may be affected by lead contamination.

    According to a report in The Roanoke Times, Marc Edwards, a civil engineering professor at Virginia Tech, has been awarded an EPA grant of nearly two million dollars to detect lead in public drinking water, and to implement measures to control lead levels in drinking water by getting members of the public involved with ongoing monitoring operations.

    According to Edwards, this funding will enable him and his team to coordinate the "largest engineering citizen-science project in American history."

    The EPA grant, which covers a three-year period, will provide the necessary support for his team, as well as collaborators from Louisiana State and North Carolina State Universities.

    Dr. Marc Edwards, an engineering professor at Virginia Tech, and an expert on municipal water quality who had been sent to study the water supply under a National Science Foundation grant Dr. Marc Edwards, an engineering professor at Virginia Tech, and an expert on municipal water quality who had been sent to study the water supply under a National Science Foundation grant

    Edwards has received wide recognition for his contribution to exposing the Flint water crisis resulting from lead contamination of the local drinking water supply. He plans to create a model that can be applied widely to enable communities to test their own drinking water.


    Edwards' laboratory already tests water samples from various parts of the country. However, the funding provided by this grant will give Edwards the financial resources to identify other communities suffering from water quality issues that puts the health of its residents at risk; particularly communities that have until now been neglected. The funding will also be used to test home water testing kits to identify the most effective solution for detecting water quality problems at home.

    LeeAnne Walters, an environmental activist who recently won the Goldman Environmental Prize for grassroots environmental activism, approached Edwards for assistance regarding Flint's water quality. Edwards together with his team of students and colleagues from Virginia Tech helped the local community test their water in the hope of identifying where the lead contamination was coming from.

    Edwards found that the city's drinking water supply became contaminated with dangerously high levels of lead after municipal officials switched to an alternative water source in 2014 in an effort to save the city money. This in turn led to a health crisis, after Mona Hanna-Attisha, a pediatrician from Michigan, found elevated levels of lead in children living in the city.

    The Flint case highlighted the problem of aging water systems across the country, and resulted in a state of emergency being implemented, together with public officials responsible for the crisis being criminally charged for their role.

    Edwards said that the Flint experience has provided his team with a model that they will continue to use moving forward, and that the EPA grant would be a big help, joking that the funding would help the project "to lose money a little less quickly."

  • Clear Water in Lakes May Actually Mean Poor Water Quality

    Don't judge a book by its cover, and by the same token, don't judge the quality of a lake by its clarity.

    Lakes dotted around agricultural hotspots typically tend to be bright green in color. This is largely due to phytoplankton and algal growth fueled by nutrients (nitrogen and phosphorus) present in agricultural fertilizers, which get washed into rivers and lakes with runoff.

    However, after analyzing water quality data collected from 139 lakes located in agricultural hotspots of Iowa over a 13 year period, scientists found that even though lakes had high concentrations of nutrients, they were remarkably clear.

    Aerial view of a small lake near the city of Clear Lake, Iowa, which represents typical landscapes surrounding the lakes in this study. About 92 percent of land within Iowa is in production agriculture and crops on these lands receive large amendments of nitrogen as anhydrous ammonia and phosphorus. Excessive algae growth caused by these nutrient inputs have turned many of the lakes in this region bright green. Surprisingly, a number of lakes in this study were clearer and appeared bluer than expected, yet are far from healthy. The study authors hypothesize that very high nitrogen levels, often >10 mg/L, suppress high chlorophyll (algae) concentrations. Aerial view of a small lake near the city of Clear Lake, Iowa, which represents typical landscapes surrounding the lakes in this study. About 92 percent of land within Iowa is in production agriculture and crops on these lands receive large amendments of nitrogen as anhydrous ammonia and phosphorus. Excessive algae growth caused by these nutrient inputs have turned many of the lakes in this region bright green. Surprisingly, a number of lakes in this study were clearer and appeared bluer than expected, yet are far from healthy. The study authors hypothesize that very high nitrogen levels, often >10 mg/L, suppress high chlorophyll (algae) concentrations.

    The study, which was recently published in the scientific journal Inland Waters, shows that the excessive fertilizer added to the lakes from agricultural runoff was so high that it killed chlorophyll containing phytoplankton and algae, which typically give polluted lakes the bright green color.

    According to lead author, Chris Filstrup, a research associate at the UMD Large Lakes Observatory and Minnesota Sea Grant, it is dangerous to mistake an increase in water clarity for an improvement in water quality, as in actual fact, the opposite is very often true. Water quality in clear lakes with high levels of nutrients is worse than that of lakes where more algae is present, yet nutrient levels are lower.

    Water clarity is often used to measure water quality, yet this study suggests this approach may not necessarily be appropriate for all regions.

    Nutrient levels rise to excessive levels after nitrogen and phosphorus from surrounding agricultural fields, animal feed lots, suburban gardens and urban landscaping gets washed into rivers and lakes with rain and melted snow. Yet, while these nutrients generally spur algal growth, they can in fact kill algae when concentrations become excessive.

    "In some of the Iowa lakes in our study we noted phosphorus levels 10 times what we'd expect to see in a northern Minnesota lake," said Filstrup. "We were astonished to see that the nitrogen levels were more than 30 times higher."

    When nutrient levels become so extreme they kill phytoplankton and algae present in the waterbody, making the lake appear clearer. In the same way that applying excessive amounts of fertilizer to soils can harm plants, rendering the soil barren, excessive amounts of nutrients in freshwater systems can kill water plants, effectively ridding lakes of algae, thus improving water clarity.

    "We thought that the low appearance of algae at high nitrogen concentrations might be due to imbalances of other nutrients, or too much shade for algae to grow, or that some algae are less green or that zooplankton eat more algae when there's a lot of nitrogen," said co-author John A. Downing, director of Minnesota Sea Grant, a scientist at the UMD Large Lakes Observatory and a professor in the UMD Department of Biology. "But none of those hypotheses panned out. The only explanation that makes sense, so far, is that high nitrogen is bad for algae."

    According to the scientists, the decrease in algae in these lakes is most likely caused by an interplay of nitrogen, phosphorus, sunlight and the landscape, which in combination can cause the excess nitrate particles to form reactive oxygen species that burst the cell walls and cell membranes of algae, damaging or killing them.

    According to Filstrup, its a bit like pouring hydrogen peroxide onto a wound. The hydrogen peroxide bursts the bacteria, making the wound fizz. A similar reaction occurs within lakes, but while there is no fizz, the reactive oxygen species that forms from nitrate can kill organic matter, including algae and phytoplankton.

    As the increased demand for agricultural crops continues to rise, along with the application of fertilizers to stimulate rapid growth of commercially produced crops, the scientists hope their study will provide some insight to other agricultural regions where extreme nutrient loading may be a cause for concern.

    Downing suggests that excessive application of nitrogen based fertilizers is not only a waste of money, it also leads to unhealthy freshwater systems, and ultimately also causes ocean dead zones such as that in the Gulf of Mexico. It is therefore important that we grow crops and manage animals wastes appropriately to avoid polluting and degrading the environment.

    Journal Reference

    Christopher T. Filstrup, John A. Downing. Relationship of chlorophyll to phosphorus and nitrogen in nutrient-rich lakes. Inland Waters, 2017; 1 DOI: 10.1080/20442041.2017.1375176

  • Suburban Drinking Water Wells in state of New York Polluted with Road Salt

    Road salt that is routinely applied to road surfaces in winter to make them less treacherous tends to linger in the environment, resulting in drinking water sources becoming contaminated. Now a new study which was recently published in the Journal of Environmental Quality, identifies geological and landscape characteristics associated with high salinity levels in water wells that supply a suburban area in Southeastern New York with drinking water.

    Salt being added to the roadway during a snowstorm. Salt being added to the roadway during a snowstorm.

    According to Victoria Kelly, Environmental Monitoring Program Manager at the Cary Institute of Ecosystem Studies, and lead author of the study, every year millions of metric tons of road salt is applied to roads across the country. This salt can seep into the soil where it can accumulate and contaminate groundwater. The aim of this study was to gain a better understanding of why some wells are more at risk to contamination by road salt than others so that we can inform managers responsible for protecting water quality.

    Kelly and her research team analyzed data from water samples collected from more than 950 private water wells supplying residents in the East Fishkill area of New York with drinking water. They found soduim levels in more than 50% of the wells was higher than the federal safety standard set by the EPA. They found that the distance of the well from the nearest road, as well as the amount of pavement nearby had a great influence on salinity levels of well water. Yet, the depth of the well and the type of road (back roads to interstate highways and everything in-between) had little influence, which was surprising.

    Chloride Concentrations in East Fishkill, N.Y. (image) Chloride Concentrations in East Fishkill, N.Y. (image)

    The researchers used GIS technology to map sodium and chloride levels of wells and to identify landscape surface features found in the area surrounding each well. They looked at local variables such as depth of well, distance from roads, elevation of the well in relation to roads nearby, impervious surface, geology of the surface soils, and type of soil to identify links between well salinity and infrastructure development.

    The study's finding echo similar studies that suggest impervious surfaces such as roads and pavements contribute to groundwater salinization and that it is ultimately a consequence of urban development. Chloride concentrations in wells located closer to roads was higher than those further away, but the type of road — whether a minor or major road — had no impact. The depth of the well had no significant impact on salt levels, and elevation in relation to roads nearby was only a factor when roads were located more than thirty meters from a nearby well.


    The study identified several hotspots where groundwater salinization was particularly high. The authors suggest that steep inclines and sharp turns in some roads could be a contributing factor as these would require a heavier application of road salt. Similarly, narrow streets which only older salt trucks can pass through could result in less efficient salt application due to outdated application technology.

    "Understanding the landscape features that lead to increased groundwater salinization can inform targeted salt application," explains Stuart Findlay, a freshwater ecologist at the Cary Institute of Ecosystem Studies and co-author of the study. "The time to act is now, as we know it can take decades or more for the salt currently in groundwater to flush out."

    The study only identified a single cold spot, located in an area where housing density was low, which reinforced the link between urbanization, road salt application and groundwater salinization.

    "In planning efforts to minimize road salt impacts, our findings tell us that smaller roads should not be overlooked and areas with a lot of pavement and porous, well-drained soils are most at risk of experiencing salinization", says Kelly. "Road salting is not one-size-fits-all undertaking. More targeted approaches will keep roads safe while reducing unintended consequences to drinking water supplies."

    Journal Reference

    Victoria R. Kelly, Mary Ann Cunningham, Neil Curri, Stuart E. Findlay, Sean M. Carroll. The Distribution of Road Salt in Private Drinking Water Wells in a Southeastern New York Suburban Township. Journal of Environment Quality, 2018; 0 (0): 0 DOI: 10.2134/jeq2017.03.0124

  • Public Happy to Pay for Improved Water Quality

    The recent lead contamination of drinking water supplied to residents living in the city of Flint, Michigan, has led to increased awareness of the need to protect watersheds.

    Ecosystem service initiatives financed by end-users (consumers) can provide landowners with a financial incentive to voluntarily take part in environmental enhancement efforts. After conducting a nationwide survey, a team of researchers from the University of Missouri-Columbia have now found that the average person would be more inclined to contribute to efforts to improve water quality than they would to other ecosystem services initiatives, such as habitat protection or flood control.

    "Our findings support the notion that ecosystem service programs need to happen at the local level," said Francisco Aguilar, associate professor of forestry in the School of Natural Resources, which is located in the MU College of Agriculture, Food and Natural Resources. "People in different areas of the country have different priorities, and that's hard to coordinate at a national level. If someone lives in a flood plain, they are going to be a lot more willing to pay for flood controls. Still, people from around the nation consistently seem to be willing to pay for water quality improvements."


    Aguilar together with his team surveyed over 1,000 households across the country for the study, asking participants to state their preference/s of which ecosystem services they would be prepared to pay for if included as part of their households utility bill. While the researchers found that participants generally tended to be more willing to contribute towards water quality initiatives rather than other ecosystem services, flood control and habitat protection varied extensively in terms of importance, depending on where the participant lived. A beautiful landscape was not valued as a vital ecosystem service, which the authors believe is because an aesthetically pleasing landscape does not easily translate into a service that provides financial benefits.

    According to co-author, Elizabeth Obeng, who worked on this research while completing her PhD at MU, a forest of trees can be viewed as a natural resource that provides valuable services to society. Trees not only release oxygen into the atmosphere, they can also help to control flooding. However, the same can't be said about an aesthetically pleasing landscape. It's hard to convince a landowner that there will be any return on their investment if they contribute to this cause.

    The survey also showed that a persons attitude towards the environment and their support of ecosystem service initiatives were more likely to affect their willingness to contribute rather than their income level. Consequently, the authors believe that behavioral factors, rather than demographics, are likely to play a more important role in determining whether a person would be willing to contribute to ecosystem enhancement initiatives.

    The report, which was recently published online in Ecosystem Services, will appear in the April (2018) print edition of the journal.

  • Microplastics in Bottled Water

    Orb Media, a D.C.-based group of investigative journalists, recently published Invisibles: The Plastic Inside Us, highlighting the global problem of microplastics - tiny bits of plastic measuring less than 5mm that are highly prevalent in the environment which are released when larger pieces of discarded plastic breakdown — in drinking water that flows from our taps.

    Now, in a follow-up investigation, they reveal that bottled water fares no better. In fact, after comparing the levels of microplastics in bottled water to that in tap water, they found that tap water was the healthier choice.

    For the study, a team of researchers from the State University of New York led by Sherri Mason tested 259 bottles of bottled water from nine countries. The researchers screened the contents of the bottles for plastic using the Nile Red method, a technique that was specifically developed to quickly detect plastic particles in seawater. The technique involves adding a red dye to the water, which adheres to free-floating bits of plastic, rendering them fluorescent under certain lighting conditions.


    After filtering the dyed bottled water samples, Sherri Mason and her team set about counting every piece of plastic measuring more than 100 microns — about the diameter of a strand of human hair. They found microplastics in 93% of the samples tested, with an average of 325 microplastic particles (10.4 > 100 micron; and 314 < 100 micron in size) per liter of bottled water tested.

    "For microplastic debris around 100 microns in size, about the diameter of a human hair, bottled water samples contained nearly twice as many pieces of microplastic per liter (10.4) than the tap water samples (4.45)," according to the new report.

    These figures are twice as high as the levels of microplastics detected in their previous study on tap water. Yet, many consumers believe that bottled water is cleaner and healthier than tap water, a belief which research has shown to be unfounded.

    Water Bottle Mineral Water Plastic Bottle Pet Water

    While this study and the resulting Orb Media report, Plus Plastic: Microplastics Found in Global Bottled Water, has not been published in a scientific journal, and therefore has not undergone the peer review process, in a BBC article covering this topic, scientific experts weighed in.

    According to Dr Andrew Mayes, a research scientist from the University of Anglia who pioneered the Nile Red method used to quantify plastic particles in the is study, the technique used involves "very high quality analytical chemistry" and he in fact considers these results to be "quite conservative".

    Michael Walker, a founding board member of the UK Food Standards Agency who also provides consulting services to the Office of the UK Government Chemist, agrees that the work is robust and the Nile Red method is sound.

    Both experts agree that while the particles measuring less than 100 microns had not been positively identified as plastics, there is a good likelihood that they are, given the fact that possible alternatives were not likely to be found in bottled water.

    But the question remains; where is this plastic originating from? The authors believe that the contamination is originating from the plastic bottles the water is packaged in or the bottling process itself. Considering that plastic bottle caps are made from polypropylene plastic (making up 54% of the plastic found in bottled water), one possibility could be that particles are shed into the contents as the bottle is opened.

    According to the Mayo Clinic, in terms of safety, bottled water is generally on a par with tap water. Bottled water is regulated by the US Food and Drug Administration (FDA), while tap water is regulated by the US Environmental Protections Agency (EPA). So the decision to drink bottled water rather than tap water is largely a matter of personal preference.

    Perhaps the safest option would be to simply filter any water that you drink to remove any microplastics or other contaminants that may be lurking in your drinking water.

  • Exposure to Herbicide Evident in Pregnant Women

    A study conducted on a cohort of pregnant women living in Central Indiana has detected glyphosate — the chemical toxin used in Roundup and other herbicides — in over 90% of the mothers-to-be.

    In a report that was recently published in the scientific journal Environmental Health, the authors suggest that glyphosate levels are linked to shorter pregnancy terms, which can have negative lifelong impacts on the offspring.

    "There is growing evidence that even a slight reduction in gestational length can lead to lifelong adverse consequences," said Shahid Parvez, assistant professor in the Department of Environmental Health Science at Indiana University and lead author of the study.

    This is the first US study of its kind to analyze urine samples of pregnant women to directly assess their exposure to the chemical glyphosate.


    According to Parvez, the study's primary finding was that of the 71 moms-to-be that made up the study cohort, 93% were found to have glyphosate at detectable levels in their urine. Glyphosate levels were higher in women living in rural areas, and in women who drank more caffeinated drinks.

    While glyphosate exposure in pregnant women cannot be denied, Parvez says that the primary source of this exposure may not necessarily be drinking water, as they initially thought. None of the drinking water samples they tested had any trace of glyphosate present, indicating that glyphosate is most likely removed during the water treatment process. However, consumption of genetically modified foods, as well as caffeinated drinks are suspected of being two primary sources of glyphosate.


    Glyphosate is used extensively in the American Midwest as a result of soybean and corn production. Residues of the herbicide can be found contaminating the environment, as well as major crops, including food items that people across the country consume daily.

    "Although our study cohort was small and regional and had limited racial or ethnic diversity, it provides direct evidence of maternal glyphosate exposure and a significant correlation with shortened pregnancy," Parvez said.

    Parvez notes that the extent of glyphosate exposure in mothers-to-be and the link between exposure and shorter gestation terms are cause for concern and warrant further investigation. Parvez hopes to expand this study to include more diversity, both ethnically and geographically, in the next cohort of pregnant women examined to determine whether the outcome will be the same.

    To reduce the likelihood of exposure to toxic pesticides such as glyphosate, it is recommended that you filter your drinking water with a good quality drinking water filter that is capable of removing pesticide contaminants, and choose healthy organically grown fresh produce and food products wherever possible.

    Journal Reference

    S. Parvez, R. R. Gerona, C. Proctor, M. Friesen, J. L. Ashby, J. L. Reiter, Z. Lui, P. D. Winchester. Glyphosate exposure in pregnancy and shortened gestational length: a prospective Indiana birth cohort study. Environmental Health, 2018; 17 (1) DOI: 10.1186/s12940-018-0367-0

  • Berkey Water Filter Contaminants Removal Guide

    It's no secret that a secure, clean source of drinking water is critical for any household. And if you're reading this article, you're probably already familiar with the general concept behind Berkey water filters: Durable, high-performing, gravity filters, built for a variety of sizes and use cases.

    But just how "high-performing" are they? Well, if you take the time to study the packaging on a Berkey filter, you will see a list of no less than 203 toxins that Black Berkeys eliminate. That's nothing to shake a stick at! When you look at the list however, you'll see things like "Dibromochloromethane" and "Hexachlorocyclopentadiene." Since these aren't exactly household names, it can be difficult to know exactly what they are, and how they affect us.

    Well, in an effort to clear up a little bit of the confusion, our friend Dan at Homestead Launch put together a handy graphic reference guide, that explains where water contaminants come from. As you can see, water contamination comes from a variety of sources: biological, industrial, agricultural, medical facilities, and even water treatment plants.

    Fortunately, Berkey filters eliminate them all, and this guide provides a really easy and visual way to show that. Take a look!

    Homestead Launch Self Sufficient Guide

    Hopefully that helps explain the contaminants that are in our water supply (and that Berkey eliminates them!). If you have a friend that might be on the fence about getting a Berkey, this would be a great resource to share with them.

    (p.s. If interested, Homestead Launch is a partner of ours and helps people plan, purchase, and develop self-sufficient homesteads. You can learn more about their great services here:

  • Commercial Pesticides More Toxic Than We're Led to Believe

    There is very little information with regard to the health and environmental effects of some ingredients in pesticides, and as a result, they are made out to be safer than what they really are.

    A comprehensive risk assessment of pesticide adjuvants — additives used to enhance the active ingredient or function of pesticides — has revealed that new regulations need to be put in place to protect both the environment and people from harmful, yet unregulated pesticide ingredients. The review, which was recently published in the scientific journal Frontiers in Public Health, cautions that ignoring the potentially harmful effects of commonly used pesticide additives can result in pesticides being labeled as safe, when in fact they are not, and can also cause confusion with regard to scientific reporting of the effects of pesticides.


    According to Dr Robin Mesnage, from King's College London and lead author of the review, exposure to some of these pesticide additives at levels they are found in the environment can affect non-target species, and can even have chronic health impacts on humans. Yet, despite this, there are no safety regulations or advisories for these additives, and no limitations regarding their acceptable daily intake or the health risk associated with exposure to pesticide residues through consumption of contaminated food or water.

    Pesticides include a concoction of chemicals, comprised of the active ingredient that repels or kills the targeted pest, together with several other chemicals such as surfactants, dyes, and anti-foaming agents, collectively referred to as adjuvants, that are added to improve the application of the pesticide or the functioning of the key active ingredient.

    However, current safety regulations only require the main active ingredient to be tested for safety, assuming that other chemical additives included in pesticide formulations have no ill effects. Consequently, the true toxicity of pesticides currently used in both domestic gardens and on agricultural crops is not clearly shown on the label.

    "Currently, the health risk assessment of pesticides in the European Union and in the United States focuses almost exclusively on the active ingredient," explains Dr Mesnage. "Despite the known toxicity of adjuvants, they are regulated differently from active principles, with their toxic effects being generally ignored."

    After reviewing the current scientific literature on pesticides, the authors suggest that the unregulated chemicals used in commercial pesticides could explain negative effects observed after exposure to presumably 'safe' pesticides.

    The review focused largely on herbicides that contain the active ingredient glyphosate, the world's most commonly used pesticide found in products such as Round-Up. The authors note that weed killer formulations containing this herbicide are comprised of so many different chemical additives that safety tests for one such weed killer does not mean another glyphosate-based weed killer is safe. The berkey water filter systems will remove glysophate from the water.

    "Studies comparing the toxicity of commercial weed-killer formulations to that of glyphosate alone have shown that several formulations are up to 1,000 times more toxic than glyphosate on human cells. We believe that the adjuvants are responsible for this additional toxic effect," says Dr Mesnage.

    The researchers also point out that neonicotinoid insecticides — whose widespread use is thought to be associated with bee colony collapse — could also be due to the toxicity of pesticide additives that are having a negative effect on non-target species. It has been shown that an additive used to help the active ingredient in these insecticides penetrate their targeted pests can have a toxic effect on bees. To compound this, traces of this toxin have been found in pollen, honey and beeswax originating from contaminated bees.

    The researchers hope this review will draw attention to the toxicity of widely used pesticides and the need for more stringent safety regulations with regard to their chemical additives.

    "Testing of whole pesticide formulations instead of just active ingredients alone would create a precautionary approach, ensuring that the guidance value for the pesticide is valid for the worst-case exposure scenario," says Dr Mesnage.

    The researchers findings are already having an impact. The European Food Safety Authority is currently reviewing the validity of pesticide safety assessment for EU countries, and the researchers hope that this will be extended to include all commercial pesticide formulations and their chemical additives.

    Journal Reference

    Robin Mesnage, Michael N. Antoniou. Ignoring Adjuvant Toxicity Falsifies the Safety Profile of Commercial Pesticides. Frontiers in Public Health, 2018; 5 DOI:10.3389/fpubh.2017.00361

  • 'Rock Moisture' Could Protect Forests from Drought

    Water trapped within layers of rock may offer forest trees a lifeline during extended periods of drought, a new study has found.

    In a report that was recently published in the scientific journal PNAS, a team of researchers examined water stored within a layer of bedrock that is typically found beneath layers of soil in mountainous areas. Sandwiched between soils above and groundwater below, it is a zone that is very often overlooked by hydrologists. But on closer inspection, the research team found that water trapped within the pores and fractures of this rock layer could play a vital role in both the local and global water cycle.

    "There are significant hydrologic dynamics in weathered bedrock environments, but they are not traditionally investigated because they are hard to access," said lead author Daniella Rempe, an assistant professor in the Department of Geological Sciences at the UT Austin Jackson School of Geosciences. "The study was designed to investigate this region directly."

    Research led by The University of Texas at Austin has found that weathered bedrock can store a significant amount of rock moisture inside its fractures and pores. This moisture in the layer of weathered rock that is commonly located beneath soils is an important part of the water cycle on the local and global level. Tree roots tap into the rock moisture and release it back into the atmosphere as water vapor, and water flows through the fractures and becomes part of the seasonal groundwater storage (blue arrows).   Credit: University of Texas at Austin Jackson School of Geosciences. Research led by The University of Texas at Austin has found that weathered bedrock can store a significant amount of rock moisture inside its fractures and pores. This moisture in the layer of weathered rock that is commonly located beneath soils is an important part of the water cycle on the local and global level. Tree roots tap into the rock moisture and release it back into the atmosphere as water vapor, and water flows through the fractures and becomes part of the seasonal groundwater storage (blue arrows). Credit: University of Texas at Austin Jackson School of Geosciences.

    The researchers discovered that water trapped within the weathered bedrock is able to sustain forest trees through periods of drought even after the top layers of soil have become parched. Field samples taken from a site in Mendocino County, Northern California revealed that as much as 27% of the region's annual rainfall was stored within the pores and cracks of the bedrock as "rock moisture".

    While the beneficial effects of rock moisture is likely to vary from region to region, and also according to topography, the researchers believe it explains how trees in this area were not affected by the severe drought experienced between 2010 and 2015, which killed over 100 million trees across California.

    "How trees can survive extended periods of severe drought has been a mystery," said Richard Yuretich, director of the National Science Foundation's Critical Zone Observatories program, which funded the research. "This study has revealed a significant reservoir of trapped water that has gone unnoticed in the past. Research of this kind can help greatly in managing natural resources during times of environmental stress."

    For the study, the team monitored rock moisture content of nine well points drilled into the weathered bedrock that were sited on a steeply sloping hillside covered in forest from 2013 to 2016.

    Lead author Daniella Rempe, an assistant professor at the Jackson School of Geosciences, with a deep borehole drill at the research site. The research team used the drill to make wells to monitor rock moisture. Credit: The University of Texas at Austin Jackson School of Geosciences. Lead author Daniella Rempe, an assistant professor at the Jackson School of Geosciences, with a deep borehole drill at the research site. The research team used the drill to make wells to monitor rock moisture. Credit: The University of Texas at Austin Jackson School of Geosciences.

    They discovered that between 4-21 inches of moisture accumulated within the weathered bedrock layer over the winter rainy season, with some variance between wells. They found that the maximum level of moisture within each well remained roughly the same for the duration of the study, including during a year that experienced significant drought. This major finding suggests that the amount of rainfall experienced in the winter dry season is irrelevant, and the total amount of rainfall has little impact on the level of rock moisture that accumulates in the bedrock.

    "It doesn't matter how much it rains in the winter, rock moisture builds up to the same maximum value," Rempe said. "That leads to the same amount of water every summer that's available for use by trees."

    When comparing average moisture levels between bedrock and surrounding soil, the research team found that rock moisture levels in all wells were higher than soil moisture for all locations monitored.

    While Rempe believes that moisture held within soil is important, the underlying bedrock could play a greater role in determining whether an area is going be water stressed during periods of drought.

    Rock moisture that is taken up by trees can potentially be evaporated from tree leaves into the surrounding air, or it can trickle down through cracks in the rock into the groundwater below. Consequently, it could play a wider role in the environment as well as climate. According to Zong-Liang Yang, a colleague of Rempe's who did not take part in the research, this study highlights the need to incorporate rock moisture in hydrological and global climate models.

    Journal Reference

    Daniella M. Rempe el al., "Rock moisture: Direct observations of a hidden component of the hydrologic cycle," PNAS (2018).

  • How Energy is Linked to the Water Crisis in Cape Town — and Why American's Should Care

    An article recently published by the Environmental Defense Fund highlights how water and energy are inextricably linked.

    Cape Town, a major South African city, is counting down the days to Day Zero, when the city's taps, which provide 4 million inhabitants with water, are expected to run dry. While extreme water restrictions and water saving measures have pushed the date back from April to November 2018, the fact remains that the city's water supply is still extremely precarious.

    "Yet, while this water crisis has been making headlines worldwide, nobody's talking about the connection between water and energy," says Kate Zerrenner, Senior Manager, Energy-Water Initiatives at the Environmental Defense Fund. "In a rapidly changing climate, we should."

    According to a 2014 study, Cape Town is not the only water-stressed city in the world — the water supply of one out of every four larger cities around the world, including two or more US cities, is under duress. Zerrenner points out that many of these cities also happen to depend on coal — the world's thirstiest source of energy.


    The supply of water and energy go hand-in-hand, an association referred to as the energy-water nexus. Energy is used during water treatment processes and to pump water across the distribution network, while water is consumed during the production and supply of energy. Consequently, our choice of energy has a direct impact on our freshwater resources.

    Conventional sources of power such as natural gas, coal and nuclear energy use an average of 25 gallons of water for every kilowatt-hour of power produced, with coal being the most water hungry, or in this case thirsty, using between 20-60 gallons to produce a kilowatt hour of electricity, depending on the cooling technology employed at the power plant.

    Back home in the US, the average household uses around 900 kWh of electricity a month, which equates to roughly 23,000 gallons of water every month. That's just to meet the power needs of a typical American household, and doesn't account for water used for drinking, cooking, showering/bathing, dishwashing, laundry, flushing, etc, etc.

    In Cape Town's case, 92% of the country's energy is supplied by coal. So even though residents in Cape Town and further afield have drastically cut back on their water usage during the prolonged drought currently affecting the region, the power plants that supply the country with energy continue to guzzle it up.

    Will US Cities Be Next?

    Climate change is causing unprecedented shifts in temperature and rainfall patterns across the world, including America, where many areas are already becoming hotter and drier. Texas is once again feeling the effects of drought, while California has suffered an extended period of drought that has already severely impacted California's agricultural sector. As these dry conditions extend eastward, more and more areas are becoming water stressed, with Miami considered one of the first US cities that could run out of water, largely due to contamination of it aquifers by saltwater intrusion from the ocean.

    Perhaps now is a good time to reassess the energy-water nexus, and make decisions that could help us save the precious little water remaining.

    Water-efficient Power Sources

    The good news is that there are water-efficient alternatives to water-hungry power sources. These come in the form of clean energy, such as solar and wind power, which both use practically zero water. What's more, they are cleaner, and therefore better for the environment too. By the same token, energy-efficiency uses no water at all.

    In the US, 85% of electricity is still supplied by water-hungry fossil fuels and nuclear. By simply improving energy efficiency and expanding solar and wind energy to meet more of the country's energy needs, while steadily reducing our dependence on more water-hungry sources of power, we can save huge amounts of water at a time when we are going to need it most.

    "This is our opportunity here and around the world as we plan for the reliability and resilience of our energy and water systems. It's no longer possible to ignore the impact our energy sources has on critical water supplies, and vice versa," says Zerrenner. "We have already begun to turn toward a cleaner energy economy. The question now is whether we can ramp things up

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