Earth Wise

A look at our changing environment.

You are here: Home / Archives for groundwater

groundwater

A hidden global water crisis

By Leave a Comment

A major crisis is unfolding beneath our feet: Earth’s continents are losing freshwater at unprecedented rates.  Recent satellite data has uncovered a hidden global water crisis, suggesting the problem is more urgent than previously thought. 

The study, which was led by researchers from Arizona State University, found that since 2002, climate change, unsustainable groundwater use, and extreme droughts have driven dramatic declines in the planet’s freshwater reserves.

The research team found that drying areas on land are expanding at a rate roughly twice the size of California every year.  Additionally, the rate at which dry areas are getting drier now outpaces the rate at which wet areas are getting wetter, reversing long-standing hydrological patterns.   

Approximately 75% of the world’s population lives in countries that have been losing freshwater for more than two decades.  As the availability of freshwater dramatically shrinks, the global population continues to expand. 

The study, which was recently published in the journal Science Advances, identifies four continental-scale “mega-drying” regions, all located in the northern hemisphere, and warns of severe consequences for water security, agriculture, sea level rise, and global stability. 

The researchers identified the type of water loss on land, and for the first time, found that 68% came from groundwater.  Groundwater loss alone now contributes more to sea level rise than melting ice sheets. 

The findings stress the urgent need for sustainable water management, international cooperation, and global policies to slow groundwater loss.

**********

Web Links

Satellites just revealed a hidden global water crisis—and it’s worse than melting ice

Unprecedented continental drying, shrinking freshwater availability, and increasing land contributions to sea level rise

Photo, posted January 16, 2012, courtesy of Kecko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Our cities are sinking

By Leave a Comment

A new study by the Columbia University Climate School has found that all of the 28 most populous cities in the United States are sinking to some extent.  This phenomenon of subsidence is not just taking place in cities on the coast, where relative sea level is an issue, but also in cities in the interior.

The primary cause of subsidence is large-scale groundwater extraction for human use.  When water is withdrawn from aquifers made up of fine-grained sediments, the pore spaces formerly occupied by water can eventually collapse, leading to compaction below and sinkage at the surface.

The fastest sinking city in the US is Houston, with more than 40% of its area subsiding more than 5 millimeters a year and 12% sinking at twice that rate.  Some local spots are going down as much as 5 centimeters a year.   These seem like very small numbers but the fact that the subsidence is often not uniform across an urban area means that there are stresses to building foundations and other infrastructure.  Parts of Las Vegas, Washington D.C., and San Francisco have particularly fast sinking zones.

There are other causes of subsidence.  In Texas, pumping of oil and gas adds to the phenomenon.  A 2023 study found that New York City’s more than one million buildings are pressing down on the Earth so hard that they may be contributing to the city’s ongoing subsidence.  About 1% of the total area of the country’s 28 largest cities faces some danger from uneven subsidence.

Overall, some 34 million Americans live in cities affected by subsidence.  Global cities facing especially rapid subsidence include Jakarta, Venice, and here in the U.S., New Orleans.

**********

Web Links

All of the Biggest U.S. Cities Are Sinking

Photo, posted December 27, 2012, courtesy of Katie Haugland Bowen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

PFAS and groundwater

By Leave a Comment

Per- and polyfluoroalkyl chemicals, more commonly known as PFAS, are a family of human-made chemicals that have been manufactured and used in a variety of industries since the 1940s.  They provide water-resistance, oil-resistance, dirt-resistance, and corrosion-resistance to a wide range of products, including food wrappers and packaging, clothing, dental floss, nonstick cookware, textiles, and electronics.

Exposure to PFAS has been linked to birth defects, thyroid disease, liver disease, kidney disease, and cancer.  These chemicals do not break down in the environment and therefore, over time, become concentrated in plants, animals, and people. 

According to a new first-of-its kind study by scientists at the U.S. Geological Survey, more than 20% of the U.S. population could be drinking groundwater contaminated with PFAS.  The study, which was recently published in the journal Science, found that those living in the Eastern U.S. are particularly likely to be exposed.

The study is the first to report national estimates of PFAS in untreated groundwater that supplies drinking water to private and public wells. The USGS research also provides the first estimate of the total number of Americans – anywhere from 71 to 95 million – who might be exposed to this contamination.

The researchers note that their estimates merely measure the existence of PFAS – before the water has undergone any treatment or filtering – meaning that, while they may be present, they may be at very low levels. 

To find a link to the detailed USGS map showing the probability of PFAS groundwater contamination in your region, visit our website: EarthWiseRadio.org.

**********

Web Links

PFAS in US Groundwater Interactive Dashboard

Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States

Photo, posted January 12, 2008, courtesy of Andrew Kraker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

South American drought

By Leave a Comment

Vast areas of South America have been gripped in drought conditions for months.  Rivers in the Amazon basin fell to record-low levels in October.  The drought has amplified wildfires, parched crops, disrupted transportation networks, and interrupted hydroelectric power generation in parts of Brazil, Bolivia, Colombia, Ecuador, Peru, and Venezuela.

The drought is related to the impact of the El Niño that was present for the latter part of 2023 and the first half of this year.  El Niño typically shifts rainfall patterns in such a way that there is reduced rainfall in the Amazon.  This is especially true during the dry season months of July, August, and September.

Forecasts earlier in the year warned that there would be extreme fire conditions during the dry season.  Indeed, the Pantanal region that spans parts of southern Brazil, Paraguay, and Bolivia has experienced one of its worst fire seasons in decades.  The lack of rainfall, low soil moisture, and drawdowns of groundwater helped to amplify fires and caused them to spread faster and farther.

The drought has strained power supplies in Brazil and Ecuador because hydroelectric power stations are producing less electricity.   Snarled transportation networks with impassible rivers have left some communities struggling to get supplies. 

Brazil’s National Center for Monitoring and Early Warning of Natural Disasters has called the current drought the most intense and widespread Brazil has ever experienced.  Late October saw 293 Brazilian municipalities facing extreme drought.

**********

Web Links

Intense, Widespread Drought Grips South America

Photo, posted August 13, 2010, courtesy of Colm Britton via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar-powered desalination

By Leave a Comment

People in remote, low-income regions far from the ocean often need to meet their water needs from groundwater and groundwater is becoming increasingly saline due to climate change.  Desalination of brackish groundwater is a huge and largely untapped source of drinking water, but there are challenges in making the process efficient and reliable.

Engineers at MIT have developed a solar-powered desalination system that requires no batteries or external power sources and is capable of producing large quantities of clean water despite the variations of sunshine throughout the day.

The system is based on the process of electrodialysis and consists of water pumps, an ion-exchange membrane stack, and a solar panel array.  What is unique about it is that it makes use of sensors and a control system that predicts the optimal rate at which to pump water through the system based on the output of the solar panels.  As a result, it uses nearly all of the electricity generated to produce clean water and does not need stored or grid-based energy.

The MIT engineers tested a community-scale prototype on groundwater wells in New Mexico over a six-month period.  The system harnessed on average over 94% of the electricity generated by its solar panels and produced as much as 5,000 liters of water per day despite large variations in weather and sunlight.

The new renewable-powered, battery-free system could provide much-needed drinking water at low cost, especially for communities where access to seawater and to grid power are limited.  The team plans to further test and scale up the system so it can supply larger communities and even whole municipalities with low-cost drinking water.

**********

Web Links

Solar-powered desalination system requires no extra batteries

Photo courtesy of Shane Pratt.

Earth Wise is a production of WAMC Northeast Public Radio

Geological thermal energy storage

By Leave a Comment

The electricity grid is increasingly using solar and wind power.  Depending on those two sources requires the ability to store energy to have on hand when the sun isn’t shining and the wind isn’t blowing.   Energy needs to be stored away to be used hours, days, or even weeks after it is produced.

Energy storage is booming.  California has increased its energy storage capacity tenfold in recent times.  One day in April, storage batteries were the largest source of electricity in the state for a period of two hours.  But batteries are not the only way to store energy.  There are chemical, electrochemical, mechanical, and thermal methods that each has potential advantages and unique features.

A project in Kern County, California, is making use of an abandoned oil field to create a long-term energy storage installation.  The plan is to retrofit depleted oil wells to store concentrated solar energy in superheated groundwater for long periods of time.  The stored heat can then be used to drive turbines when electricity is needed.

Some 1,200 feet below the surface of the oil field are pockets of permeable sandstone that have been emptied of the oil they previously contained.   An array of parabolic mirrors will gather solar energy that will heat silicon oil in an underground loop to 700 degrees Fahrenheit.  The oil pipeline will heat up groundwater down below.  When electricity is needed, the heated groundwater will be brought to the surface to operate turbines.

There is no new technology involved.  The individual aspects have never all been combined before, but the likelihood of success is high.  There are lots of depleted oil fields that could be used this way in the future.

**********

Web Links

Can a California Oilfield Be Retrofitted to Store Solar Energy?

Photo, posted July 18, 2017, courtesy of John Ciccarelli / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Oases and desertification

By Leave a Comment

Oases are important sources of water for people, plants, and animals in the world’s desert areas.  In fact, oases sustain 10% of the world’s population despite taking up only about 1.5% of land area.  They form when groundwater flows and settles into low-lying areas or when surface meltwater flows down from nearby mountains and pools.

New research from the Chinese Academy of Sciences has found that oases added 85,000 square miles of new area from 1995 to 2020, mostly from artificial expansion projects, but over the same period lost 52,000 square miles from desertification and water scarcity.  The net gain of 33,000 square miles is not considered to be sustainable given that it was mostly due to artificial causes.  The oasis expansion projects were in Asia but losses due to desertification were also mostly in Asia.

Today, oases are found in 37 countries.  Increases in oases mostly come from people intentionally converting desert land into oases using runoff water and groundwater pumping, creating grasslands and croplands. This mostly has taken place in China.

Human over-exploitation of dwindling groundwater can limit the sustainability of oases as can the long-term loss of glaciers.

The study highlighted ways to sustain healthy oases, including suggestions for improving water resource management, promoting sustainable land use and management, and encouraging water conservation and efficient water use.  As the climate continues to change, these efforts will be increasingly important for a significant portion of the world’s population.

**********

Web Links

World’s Oases Threatened By Desertification, Even As Humans Expand Them

Photo, posted August 3, 2008, courtesy of Paul Williams via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Forever chemicals in water

By Leave a Comment

So-called forever chemicals are pervasive in a wide range of products.  These are man-made substances called per- and polyfluoroalkyls or PFAS.  They get their unfortunate nickname because the chemical bonds in them are so strong that the compounds don’t break down for hundreds or even thousands of years.

PFAS compounds are used in makeup, dental floss, nonstick pans, food wrappers, pesticides, stain-resistant fabrics and carpets, firefighting foams, and more.  High level exposure to some of these chemicals has been linked to a variety of health problems include high cholesterol, liver and immune system damage, pregnancy problems, and kidney and testicular cancer.

A recent study published in the journal Nature Geoscience has found that PFAS chemicals are showing up in water around the world.  The study looked at more than 45,000 water samples and found that about 31% of ground water tested that wasn’t even near any obvious source of PFAS contamination had levels of the chemicals that are considered harmful to human health by the EPA.  About 16% of surface water samples – streams, rivers, ponds, and lakes – also not near any known source, had similar hazardous PFAS levels.

The EPA has now imposed strict new drinking water limits for six types of PFAS.  Going forward, water systems are required to monitor for these chemicals and remove them if they are found above allowable levels.  The new rules make the United States one of the strictest countries in the world in terms of regulating PFAS in water.

**********

Web Links

EPA puts limits on ‘forever chemicals’ in drinking water

Photo, posted May 5, 2020, courtesy of Brandon Shaw via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The East Coast is sinking

By Leave a Comment

Most of the world’s largest cities are located in coastal regions and coastal regions are on the front lines of the climate crisis.  Human populations continue to migrate towards low-elevation coastal areas at the same time that sea level rise is accelerating.  Coastal communities worldwide are increasingly vulnerable to the dangers of flooding and erosion.  With these hazards occupying a great deal of attention, there has been less attention paid to the dangers of land subsidence.

A recent study by researchers at Virginia Tech and the US Geological Survey using satellite data shows that parts of America’s east coast are sinking, and the culprit is the withdrawal of too much water from the aquifers beneath these coastal areas.

A series of overlapping aquifers extends all the way from New Jersey to Florida along the coast, providing a reliable source of water for drinking, irrigation, and industrial uses.  Even though these areas get regular rainfall, the deeper aquifers can take hundreds or even thousands of years to refill once water is pumped out.  Once water is removed, soils can compress and collapse, causing the land surface to sink.

Cities that were built on drained marshland or on fill soil are especially vulnerable to compaction. 

Seal level rise is slow, but it is insidious and continuous.  Add land subsidence to the mix and effects multiply.  Places like Boston, New York, Washington DC, Roanoke, Savannah, Jacksonville, and Miami, among others, all are increasingly vulnerable to these coastal hazards.  The combined effects of sea level rise and subsidence may even triple the prospects for flooding areas over the next few decades.

**********

Web Links

As Aquifers Are Depleted, Areas Along The East Coast Of The US Are Sinking

Photo, posted August 7, 2015, courtesy of Tracy Robillard / NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global groundwater depletion

By Leave a Comment

Groundwater is found underground in aquifers and it bubbles up naturally into springs, streams, and rivers.  It’s also often pumped out for use by people. 

Researchers from UC Santa Barbara have conducted the largest assessment of groundwater levels across the globe, spanning 170,000 wells and nearly 1,700 aquifers across more than 40 countries. The team compiled and analyzed data, including 300 million water level measurements taken over the past 100 years.

In the study, which was recently published in the journal Nature, the researchers found that groundwater is rapidly declining across the globe, often at accelerating rates.  In fact, they found that groundwater is dropping in 71% of the aquifers studied.  The rates of groundwater decline observed in the 1980s and ’90s sped up from 2000 to the present, highlighting how a bad problem became even worse. 

But there are some reasons to be optimistic.  That’s because in 16% of the aquifers studied, the researchers found that the rate at which groundwater levels are falling in the 21st century had slowed down compared to the 1980s and ‘90s.  The research team highlighted specific success stories in Thailand, Arizona, and New Mexico, where groundwater has begun to recover after interventions to better regulate water use or redirect water to replenish depleted aquifers.

While groundwater depletion isn’t inevitable, the researchers stress that aquifer recovery will require interventions.  They hope this study will help scientists, policy makers, and resource managers better understand the global dynamics of groundwater. 

**********

Web Links

Global groundwater depletion is accelerating, but is not inevitable

Photo, posted October 4, 2016, courtesy of Deborah Lee Soltesz / Coconino National Forest via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater and climate change

By Leave a Comment

Groundwater is the vast reserve of water beneath Earth’s surface.  It’s an essential resource for humans, plants, animals, and other living organisms.  According to the United States Geological Survey, about 30% of all readily available freshwater in the world is groundwater.  In areas lacking sufficient surface water supply from rivers and reservoirs,  groundwater is critical for meeting the region’s drinking water and food production needs.

But climate change, as well as global population growth, is stressing groundwater resources.  As precipitation becomes less reliable due to climate change, surface water bodies can drop too low to provide the needed water.  As a result, people turn to groundwater. Depletion of groundwater is already a significant problem, and over-pumping will only increase further as climate change makes traditional sources of water less reliable.

According to a new study led by researchers from the University of Michigan, farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation.  The study, which was published in the journal Science Advances, found that the rate of groundwater loss could triple by 2080 if this trend continues, further threatening India’s food and water security. 

India is the second-largest global producer of common cereal grains such as rice and wheat, and recently passed China as the world’s most populous nation. Without interventions to conserve groundwater, the research team finds that warming temperatures will likely amplify India’s groundwater depletion problem, further threatening the country’s food and water security.  

********** 

Web Links

Groundwater depletion rates in India could triple in coming decades as climate warms, study shows

Where is Earth’s Water?

Photo, posted August 2, 2013, courtesy of Rajarshi MITRA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Airplanes, corn, and groundwater

By Leave a Comment

The aviation industry wants to slash its greenhouse gas emissions.  One proposed strategy is to replace ordinary jet fuel with ethanol.  Ethanol in this country mostly comes from corn.  The airlines are enthusiastic about the idea; corn farmers are enthusiastic about the idea.  Ethanol suppliers are obviously enthusiastic about it.  But is it a good idea?

Today, nearly 40% of America’s corn crop is turned into ethanol.  Twenty years ago, the figure was around 10%.  The massive growth was the result of mandates for ethanol augmentation of gasoline for environmental reasons.

But the environmental benefits of corn ethanol have always been controversial at best when all the energy factors are considered. But apart from that, a very serious issue is that corn is a water-intensive crop, and it can take hundreds of gallons of water to produce a single gallon of ethanol.  As the climate warms and corn crops expand, groundwater in many corn-growing areas is being increasingly depleted and groundwater provides half our drinking water and meets far more than just the needs of corn farmers.

Corn farmers and ethanol producers see the rapid growth of electric vehicles as a threat to their lucrative business of supplying the auto fuel industry.  The ambitious goals of the airline industry to reduce its emissions would likely require nearly doubling ethanol production.

The situation is a powerful example of the tradeoffs that can arise as the world tries to make the transition away from fossil fuel.  Even green solutions can have their own environmental cost and sometimes that cost may be too steep.

**********

Web Links

Airlines Race Toward a Future of Powering Their Jets With Corn

Photo, posted September 2, 2007, courtesy of Rosana Prada via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater loss

By Leave a Comment

Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock.  It is held in aquifers and bubbles up naturally into springs, streams, and rivers, but also is pumped out for use by people.  Groundwater provides almost half the drinking water in the U.S. and is a main source of water for agriculture.

The world’s supply of groundwater is steadily declining.  The combination of climate change and human population growth is increasingly diminishing groundwater.

A study by the Desert Research Institute published in the journal Nature Communications has mapped the global permanent loss of aquifer storage capacity for the first time.  Computer modeling with advanced machine learning techniques has provided a detailed picture of the world’s groundwater situation.

The study found that global aquifer storage capacity is disappearing at a rate of 10 miles a year, about the size of 7,000 Great Pyramids of Giza.  The loss of groundwater storage is permanent, forever reducing the amount of water that can be captured and stored because the pumping of groundwater can cause the ground surface above to sink, collapsing the space where water can be stored.

About 75% of this subsidence is occurring over cropland and urban regions.  The United States, China, and Iran account for most of the global groundwater storage loss but many other places in the Middle East and Asia are experiencing significant groundwater withdrawal as well.

Most regions of the world do not have monitoring programs for groundwater pumping.  The study underscores the need to better understand this issue on a global scale and take appropriate action before it is too late.

**********

Web Links

Scientists Map Loss of Groundwater Storage Around the World

Photo, posted August 7, 2015, courtesy of NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Groundwater Crisis | Earth Wise

By Leave a Comment

The majority of U.S. drinking water systems rely on groundwater, as do America’s farms.  Even though groundwater is a crucial resource for the country, there is no central oversight or even monitoring of its status across the country.  The health of the country’s aquifers is difficult to gauge.

The New York Times spent months amassing data from 80,000 wells across the country by reaching out to federal, state, and local agencies nationwide.

The survey found that 45% of the wells examined showed a statistically significant decline in water levels since 1980.  Forty percent of the sites reached record-low water levels over the past 10 years, with last year the worst yet.

Over pumping is the biggest problem.  State regulations tend to be weak and there is no federal oversight.  The warming climate reduces snowpack, which means less water in rivers, increasing the need to tap into groundwater.  Warmer weather means thirstier plants, increasing the demand for water.

It is a nationwide problem, not just one in the drought-ridden West.  Arkansas, which produces half of the country’s rice, is pumping groundwater twice as fast as nature can replace it.  Three-quarters of Maryland’s wells have seen substantial drops in water levels.

As groundwater is pumped out, the empty space can collapse under the weight of the rock and soil above it, permanently diminishing the capacity for future groundwater storage.

There are likely to be parts of the U.S. that run out of drinking water and groundwater depletion threatens America’s status as an agricultural superpower. Objectively, the status of American groundwater is a crisis that threatens the long-term survival of communities and industries that depend on it. 

**********

Web Links

Five Takeaways From Our Investigation Into America’s Groundwater Crisis

Photo, posted July 25, 2009, courtesy of Chris Happel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Power And Water | Earth Wise

By Leave a Comment

Solar power is a prime example of clean energy, but it does not come without complications and potential problems.  One problem that has arisen in the Californian desert is the effect on scarce water supplies.  Solar farms don’t use up water when they are operating but they consume it when they are being built.

One of the densest areas of solar development in North America is in a corridor along Interstate 10 near Palm Springs, California.  Multiple utility-scale solar projects are underway near the small town of Desert Center.  The projects are being built on public land overseen by the Department of Interior’s Bureau of Land Management.  The location is ideal for solar power projects:  endless sunshine, nearby transmission lines to distribute power, and a major highway for easy transportation of construction materials.

The problem is that during construction of the solar farms, the law requires developers to reduce the amount of dust being generated that can otherwise spread health problems like Valley Fever.  Preventing dust from flying requires water and lots of it.

The water comes from groundwater and building the solar farms is drying up local wells and emptying the aquifer that is part of the Chuckwalla Valley Groundwater Basin.  For the people who live in Desert Center and adjacent areas, this is a serious problem. It is also a problem for the desert ecosystem that supports palo verde and ironwood trees as well as endangered desert tortoises.

This isn’t an easy problem to solve. Seven approved new utility-scale solar projects in the area will provide enough electricity to power 2 million homes. But having enough water to build those projects won’t be easy.

**********

Web Links

Solar Is Booming in the California Desert, if Water Issues Don’t Get in the Way

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water For Arizona | Earth Wise

By Leave a Comment

The Phoenix area is the fastest growing region in the country.  Arizona’s two major sources of water – groundwater and the Colorado River – are dwindling from drought, climate change, and overuse.  Officials in the state are considering a radical plan to construct a desalination plant off the Mexican coast that will take the salt out of seawater, and then pipe that water hundreds of miles, much of it uphill, to Phoenix.

The project is the brainchild of the Israeli company, IDE, which is one of the world’s largest desalination companies.  IDE has asked Arizona to sign a 100-year contract to buy water from the project. 

There are multiple complications surrounding the plan.  Desalination plants are common in California, Texas, and Florida, and in more than 100 other countries.  But the Arizona project is unusual because of the distance involved and because the state is landlocked.  The water would have to travel 200 miles and climb 2,000 feet along the way.

There is also the issue of waste brine, which is a major output of desalination plants.  In this case, the brine would flood the northern Gulf of California, potentially threatening a productive fishery.  In addition, the pipeline, as well as electrical transmission lines, would have to go through the Organ Pipe Cactus National Monument, a UNESCO biosphere reserve.

The plant would be located in Puerto Peñasco, a struggling town with its own water problems.

With booming home construction going on in the Phoenix area, the need for more water continues to grow.  Whether this plan will be approved by Arizona and by Mexico remains to be seen.

**********

Web Links

Arizona, Low on Water, Weighs Taking It From the Sea. In Mexico.

Photo, posted September 26, 2008, courtesy of Dan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rain Gardens And Residential Pollution | Earth Wise

By Leave a Comment

Stormwater runoff has become the largest source of residential pollution for waterways.  As rainwater runs down roofs, over driveways and patios, and off other hard surfaces, it can pick up pollutants as it flows directly into streams, wetlands, lakes, and groundwater aquifers.  That water is typically routed directly through stormwater pipes and ditches with little filtering or treatment.  The main emphasis is on getting the water off of people‘s property as quickly and efficiently as possible to avoid flooding.

Many municipalities are dealing with the problem by installing rain gardens, which are a type of green infrastructure in commercial spaces that slow down and treat water before it enters streams, wetlands, and other bodies of waters.  When designed and installed properly with appropriate plants, rain gardens are like miniature water treatment facilities   Water gathers in the rain garden, soaks into the soil, and is taken up by plants.  The plants filter nutrients, sediments, and toxic materials from the runoff before excess water ever gets to waterways.

Homeowners are being encouraged to build their own rain gardens.  They need to familiarize themselves with how runoff from their roof, driveway, sidewalk, and roads is currently being routed and treated.  The idea is to try to incorporate that runoff into a rain garden design with sufficient area and infiltration rates.  The runoff would ultimately flow out from a safe, designated location into storm drains at a slower rate than from the previous impervious surfaces.  Homeowners would need to work with their local jurisdictions to find out the requirements for re-routing water in their area and make sure any modifications prevent erosion and protect nearby homes, roads, and other infrastructure.

**********

Web Links

Rain gardens help keep pollutants out of waterways

Photo, posted March 3, 2017, courtesy of Jeremy Jeziorski / Oregon Convention Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New York Is Sinking | Earth Wise

By Leave a Comment

The rising seas represent a threat to coastal cities across the globe.  Increasing that threat is the fact that most global cities are slowly sinking as the earth beneath them settles and groundwater is removed.   Another factor that has seldom been considered is that in major metropolises, the weight of large, concrete-and-steel skyscrapers may be hastening the sinking.

A new study by the U.S. Geological Survey published in the journal Earth’s Future estimated the weight of every building in New York City – 1.085 million of them – which they determined to add up to 1.68 trillion pounds – and estimated the downward force of those structures across the city.

The study found that buildings have a greater effect in areas that are rich in clay compared with those areas where sand or bedrock predominate.  The softer the soil, the more compression there is from buildings.  It wasn’t a mistake to build large buildings in New York, but it is important to understand that doing so pushes down the ground more and more.

The study determined that New York is sinking by around 1 to 2 millimeters each year, although some areas are sinking much faster.  The researchers say that cities must plan for future sinking, which will exacerbate the impact of rising seas. Sea levels are rising 1 to 2 millimeter each year, so the subsidence caused by the weight of buildings is equivalent to moving a year ahead in time with regard to rising ocean levels.  This is not a cause for immediate panic, but it is important to understand that this ongoing process only increases the risk of inundation from flooding.

**********

Web Links

New York City Sinking Under Weight of Skyscrapers

Photo, posted January 29, 2016, courtesy of Always Shooting via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California: Drought Or No Drought? | Earth Wise

By Leave a Comment

Just a few months ago, millions of people in California were living under challenging water conservation rules.  The past three years were the driest on record and reservoirs were depleted, landscapes dried up, and the snowpack in the Sierras at very low levels.

But in recent months, a dozen atmospheric river storms have brought huge amounts of rain and snow to the state.  Twelve out of 17 major reservoirs in the state have been replenished, the snowpack is over 240% of normal, and brown hills are blooming once again.

So, is the California drought over?  According to the experts, the answer is:  sort of.

The record snowpack and heavy rains have erased the most severe aspects of the drought in many parts of the state.  Only 9% of the state is now experiencing “severe” or “exceptional” drought, down from 55% last fall.

But the changes are basically all at the surface.  Groundwater in the state is still extremely low and the state’s cities and farms are still using more of it than is appropriate.  The state has been unwisely overusing its groundwater aquifers because of the drought and this one year of heavy rains cannot replenish levels that have been dropping for years.

California has been rolling back many of the most severe drought restrictions that had been imposed but has not entirely lifted the drought emergency status.  Meanwhile, the massive snowpack in the mountains will begin to melt as the weather warms and, in many areas, Californians will face flooding.  Water is a complicated business in California.

**********

Web Links

Drought or no drought? California left pondering after record winter deluge

Photo, posted August 28, 2019, courtesy of Joyce Cory via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

El Paso’s Water Future | Earth Wise

By Leave a Comment

El Paso, Texas is part of the Paso del Norte region, which includes Ciudad Juarez in Mexico and Las Cruces, New Mexico.  The population on both sides of the border is booming, approaching 3 million people.  The region’s primary water source is the Rio Grande River.  But that river is declining.

Rising temperatures and decreasing rainfall have led to diminishing flow in the river.  Eighty percent of the river’s flow has historically been diverted to agriculture, but the reduced flow of the Rio Grande has forced many farmers to reduce planting or change to less water-hungry crops.  The river is expected to continue to decrease its flow as time goes by.

The city of El Paso gets 40% of its water supply directly from the Rio Grande.  Urban water authorities in the region are scrambling to find ways to provide cities with alternative supplies of water.

El Paso now gets some of its water from a desalination plant, which is the world’s largest inland municipal desalination plant.  The water comes from brackish groundwater rather than from the sea.  The briny waste from the plant is piped to an injection well many miles way and is permanently stored 4,000 feet underground.

El Paso continues to seek new water sources and reduce its water use.  It gets much of its water from wells drilled in nearby aquifers.  It is working to make this use of groundwater more sustainable.  The city recycles used residential water through its so-called purple pipe system, which cleans up waste water and delivers it for non-potable use on golf courses and park lawns. 

Like many places in the increasingly dry west, El Paso’s water future is uncertain. 

**********

Web Links

As Rio Grande Shrinks, El Paso Plans for Uncertain Water Future

Photo, posted April 29, 2018, courtesy of R. Baire via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)