aquifers

El Paso’s Water Future | Earth Wise

November 21, 2022 By EarthWise 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.

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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

The Atmosphere Is Thirstier | Earth Wise

May 9, 2022 By EarthWise Leave a Comment

The American West is in the throes of a two-decade-long drought. The climate there is getting warmer and drier, which has led to increasing demand for water resources from both humans and ecosystems. According to a new study by the Desert Research Institute and collaborators, the atmosphere across much of the U.S. is also demanding a greater share of water than it used to.

Evaporative demand, which is also called atmospheric thirst, is a measure of the potential loss of water from the earth’s surface up to the atmosphere. It is a function of temperature, humidity, wind speed, and solar radiation. The study, published in the Journal of Hydrometeorology, assessed trends in evaporative demand during a 40-year period from 1980-2020.

The study’s findings showed substantial increases in atmospheric thirst across much of the Western U.S. over that period, with the largest increases centered around the Rio Grande and Lower Colorado rivers. This is important because atmospheric thirst is a persistent force in pushing Western landscapes and water supplies toward drought.

The study found that, on average, increases in temperature were responsible for 57% of the changes observed in atmospheric thirst, humidity 26%, and the other factors playing lesser roles.

For farmers and other water users, increases in atmospheric thirst mean that, in the future, more water will be required to meet existing water needs. Crops already require more water than they did in the past and can be expected to require more water in the future. Over time, for every drop of precipitation that falls, less and less water is likely to drain into streams, wetlands, aquifers, or other water bodies.

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New study shows robust increases in atmospheric thirst across much of U.S. during past 40 years

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Safely Storing Carbon | Earth Wise

February 28, 2022 By EarthWise Leave a Comment

As carbon dioxide levels continue to increase in the atmosphere and emissions reductions aren’t happening as fast as needed, there is growing interest in carbon capture and storage technologies.

The idea is to capture the CO2 emitted from industrial processes or from the burning of fossil fuels in power generation, and then permanently store it out of harm’s way. There are several different types of sites where the CO2 might be stored. Deep saline aquifers are particularly desirable for the purpose, but depleted hydrocarbon reservoirs are commonplace and relatively simple to use. These are oil and gas wells that have been drained of their resources.

In many cases, CO2 has already been injected into these depleted wells as a means of enhanced oil recovery. Therefore, such wells provide a unique opportunity to study what happens to carbon dioxide when it’s stored in these places.

Researchers from Oxford University recently published a paper in the journal Nature that compared the state of depleted wells with injected carbon dioxide to that of wells without the injected gas. They found that nearly 3/4 of the CO2 was dissolved in the groundwater. Unexpectedly, they also found that 13-19% of the carbon dioxide was converted into methane by methanogenic bacteria. Methane is less soluble, less compressible, and less reactive than carbon dioxide.

Producing methane in these wells is therefore undesirable. Deeper sites that have temperatures too high for the bacteria to thrive are much more suitable. This research is important for identifying future carbon capture and storage sites and for designing long-term monitoring programs that are essential for low-risk, long-term carbon storage.

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Safer carbon capture and storage

Photo, posted November 6, 2015, courtesy of CL Baker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar And Wind Energy And Groundwater

December 30, 2019 By EarthWise Leave a Comment

The use of both solar and wind farms has been expanding all over the country as a way of lowering carbon emissions from the electric power sector. According to a new study led by Princeton University, these renewable energy sources have another important benefit: they keep more water in the ground.

The study focused on drought-prone California where both solar and wind power have been expanding dramatically. California is the largest agricultural producer in the United States and has also experienced one of the most severe droughts on record between 2012 and 2017.

The study determined that increased solar and wind energy can reduce the reliance on hydropower, especially during times of drought.

The study looked at multiple scenarios in order to determine how much solar and wind energy should be used to maximize economic revenue and to see how solar and wind power could ensure groundwater recovery. They created a framework to quantify the optimal pathways for maximizing hydroelectricity and agricultural income while avoiding groundwater depletion.

During the long drought, California’s agriculture industry relied heavily on tapping into groundwater stores, which is an unsustainable practice. With more droughts likely to occur in California as well as increasing water demand from the growing California population, the burden on the state’s groundwater supply will only grow.

According to the researchers, it is far more practical to impose further regulations on groundwater use if sufficient solar and wind power is deployed. They caution that these resources need to be deployed long before groundwater aquifers are depleted, or it will be too late for them to do any good.

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Solar and Wind Energy Preserve Groundwater for Drought, Agriculture

Photo, posted December 11, 2014, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up Storm Water

October 4, 2018 By EarthWise Leave a Comment

Storm water reclamation is an important activity for cities with limited water resources, such as those in Southern California. Many places have small-scale reclamation efforts using rain gardens and bioswales. Collecting storm water on a large scale faces a number of problems.

Saving Saharan Oases

February 6, 2017 By EarthWise

An oasis is an isolated area of vegetation in a desert, typically surrounding a spring or similar water source such as a pond or a small lake. Oases can provide habitat for animals as well as people. Oases have long been essential for trade and transportation routes in desert areas; caravans typically travel via oases so that supplies of water and food can be replenished.

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