(Press-News.org) One-third of the water catchments included in a Victorian study had not recovered from a severe drought nearly eight years later, Australian-first research from Monash University shows.
Globally, science holds the common view that rivers and underground water supplies eventually replenish following periods of severe drought or flood.
This study, led by Dr Tim Peterson from Monash University's Department of Civil Engineering and published today in the prestigious international journal Science, is the first in the world to challenge this widely held view.
Researchers used statistical models of rainfall and streamflow at 161 water catchments across Victoria, each with over 30 years of data and no upstream dams or water extractions. The area surveyed is about the size of the United Kingdom or half that of the US state of California.
Dr Peterson and research colleagues from The University of Melbourne discovered that when the drought ends, some rivers continue to behave like they're still in a drought for years afterwards and many have not yet recovered.
Specifically, the runoff, as a fraction of precipitation, had not recovered in 37 per cent of water catchments in Victoria after Australia's Millennium Drought, and the number of recovering water catchments remained stagnant.
This means that 100mm of precipitation before the drought in 1990 created more river flow than the same 100mm in 2017, therefore delivering a 30 per cent reduced streamflow after the drought.
The number of water catchments with a low or very low runoff state increased rapidly from 1996 to the end of the meteorological drought in summer 2010. By 2011, only 15 per cent of water catchments had recovered.
The Millennium Drought, regarded as one of the worst droughts to hit Australia in its modern history, crippled the Murray-Darling Basin and placed extreme pressure on ecosystems, agricultural production and urban water supply in the south-eastern part of the country. It ended with a La Nina weather event in 2010.
A water catchment, or watershed, is any area of land that captures precipitation, which then flows into common outlets, such as a river, stream, bay or lake. Almost all of Victoria's water supply comes from streamflow.
Dr Peterson said the regeneration of water catchments after severe drought had major implications for global long-term water resource planning and aquatic environments, especially when climate change is added on top of their findings.
"Our findings suggest hydrological droughts can persist indefinitely after meteorological droughts and that the mechanism for recovery remains an open question," Dr Peterson said.
"This new discovery just appears to be the way catchments naturally behave. It's not explained by factors like land use. They are just more complex than we thought."
Each water catchment analysed for this study had at least 15, seven and five years of streamflow observations before, during and after the Millennium Drought respectively, and had no major upstream reservoirs or river extractions.
Across all 161 water catchments, researchers found eight years into the drought, 51 per cent of the catchments switched into a low or very low runoff state. When the drought ended in 2010, primarily the eastern water catchments returned to a normal runoff state (see figure).
Importantly, by mid-2017, nearly eight years after the drought, more than one-third of water catchments still remained within a low runoff state, and have not recovered back to the pre-drought behaviour.
Dr Peterson said evidence also suggested vegetation responded to the drought by increasing the fraction of precipitation going to transpiration - the process of water movement through a plant and its evaporation from leaves.
"Practically, this implies that in response to the Millennium Drought, vegetation in selected water catchments responded by maintaining similar rates of transpiration," he said.
Researchers say they've shown that water catchments are more complex than previously thought and that the findings are helping water agencies to better plan for the future.
Dr Peterson and his co-authors at The University of Melbourne have been working with, and communicating the findings to, the Victorian and national water agencies; most recently through the broader findings of the Victorian Water and Climate Initiative.
He says: "it's exciting that the findings have already begun to be used in how water is managed. We are now developing mathematical tools to further help water management use these findings to ensure long-term water supply within a challenging and changing climate."
INFORMATION:
Dr Tim Peterson (Monash University, Department of Civil Engineering) led this study, in close collaboration with Dr Margarita Saft, Dr Murray Peel and Dr Andrew John (The University of Melbourne, Department of Infrastructure Engineering).
The study was predominantly funded by the Victorian Government's Victorian Water and Climate Initiative with more recent support from the Australian Research Council.
Please visit https://doi.org/10.1126/science.abd5085 for more information.
MEDIA ENQUIRIES
Leigh Dawson
T: +61 455 368 260 E: media@monash.edu
A new approach to genomic species delineation could impact policy and lend clarity to legislation for designating a species as endangered or at risk.
The coastal California gnatcatcher is an unassuming little gray songbird that's been at the epicenter of a legal brawl for nearly 28 years, ever since U.S. Fish and Wildlife Service listed it as threatened under the Endangered Species Act.
Found along the Baja California coast, from down south in El Rosario, Mexico to Long Beach, Calif., its natural habitat is the rapidly declining coastal sagebrush that occupies prime, pristine real estate along the West Coast. When this particular gnatcatcher, Polioptila californica, was granted protection, the region's real estate developers went to court to get it delisted. ...
Viruses require the resources of an infected cell to replicate and then infect further cells, and transfer to other individuals. One essential step in the viral life cycle is the production of new viral proteins based on the instructions in the viral RNA genome. Following these construction plans, the cell's own protein synthesis machine, called the ribosome, produces the viral proteins.
In the absence of viral infection, the ribosome moves along the RNA in strictly defined steps, reading three letters of RNA at a time. This three-letter code defines the corresponding amino acid that is being attached to the growing protein. It almost never happens that the ribosome slips one or two RNA letters forward or backward instead of following the regular three-letter steps. When such a slip ...
Irvine, CA - May 13, 2021 - A new University of California, Irvine-led study finds low serum levels of the sugar N-acetylglucosamine (GlcNAc), is associated with progressive disability and neurodegeneration in multiple sclerosis (MS).
The study, done in collaboration with researchers from Charité - Universitätsmedizin Berlin, Germany, and the University of Toronto, Canada, is titled, "Association of a Marker of N-Acetylglucosamine With Progressive Multiple Sclerosis and Neurodegeneration," The study was published this week in JAMA Neurology.
The study suggests that GlcNAc, which has been previously shown to promote re-myelination and suppress neurodegeneration in animal models of MS, ...
First co-author, Junior Research Associate of the Rheological and Thermochemical Research Lab Richard Djimasbe, comments, "To obtain bitumen as a half-solid product from heavy oil, you have to extract light fractions, and the rest is non-oxidized bitumen. Because of the relatively low ratio of light fractions in heavy oil, it's a simple and cheap way of bitumen production. The method allows for rational use of both heavy oil and light oil."
Lab Head Mikhail Varfolomeev adds, "One of the priorities of our World-Level Research Center in Liquid Hydrocarbons is the use of heavy oils, which constitute the majority of reserves both in Russia and in the world. One of the most important parts of this is extraction and refining of heavy ...
Laura Riesenberg was visiting a local amusement park with three of her children when she suffered a massive heart attack.
"I was down for about 20 minutes and they defibrillated me twice on site, possibly three times," she says. "Obviously, I was unaware of it. I know from reading the reports what happened."
"I was extremely fortunate that someone found me within seconds of collapsing," says Riesenberg. "Had it happened anywhere else I wouldn't be talking to you right now. If I had been in the basement doing laundry, I would have been in trouble."
The 51-year-old Loveland, Ohio, resident ...
Pregnant Aussie mums are being denied access to medications which treat severe nausea and vomiting by pharmacists and medical practitioners because of misleading labels and a lack of awareness about clinical guidelines.
A new study surveyed 249 Australian women who suffered from severe nausea and vomiting during pregnancy (NVP) or hyperemesis gravidarum (HG) and examined their experiences in accessing medications during pregnancy.
One in four women reported being denied medications for NVP/ HG at some stage during pregnancy. This most commonly involved the over-the-counter medicine doxylamine and interactions ...
PHOENIX, Ariz. -- May 13, 2021 -- In the largest study of the associations between smoking and cardiovascular disease on cognitive function, researchers at the Translational Genomics Research Institute (TGen), an affiliate of City of Hope, found both impair the ability to learn and memorize; and that the effects of smoking are more pronounced among females, while males are more impaired by cardiovascular disease.
The results appear today in the journal Scientific Reports.
Previous attempts to quantify cognitive function among smokers and assess sex differences produced mixed results. The TGen researchers attribute this to the limited size of previous data sets. By ...
College Park, Md. - Companies have often considered app adoption among their customers to have a positive impact on customer spending. According to new research from marketing professor P.K. Kannan at the University of Maryland's Robert H. Smith School of Business, higher app adoption among hotel chains could be linked to lower spending among lower-level loyalty customers, who are more likely to use apps to get the best deals.
Kannan worked with Xian Gu, an assistant professor of marketing at Indiana University, for the research, published as "The Dark Side of Mobile App Adoption: Examining the Impact on Customers' Multichannel ...
When a piece of conducting material is heated up at one of its ends, a voltage difference can build up across the sample, which in turn can be converted into a current. This is the so-called Seebeck effect, the cornerstone of thermoelectric effects. In particular, the effect provides a route to creating work out of a temperature difference. Such thermoelectric engines do not have any movable part and are therefore convenient power sources in various applications, including propelling NASA's Mars rover Perseverance. The Seebeck effect is interesting for fundamental physics, too, as the magnitude and sign of the induced thermoelectric current is characteristic of the material and indicates ...
A small drug molecule that appears to protect normal tissue from the damaging effects of radiation, may simultaneously be able to boost the cancer-killing effect of radiation therapy, according to a new study led by scientists at University of Iowa, University of Texas Southwestern Medical Center, and Galera Therapeutics, Inc.
The study, published online May 12 in Science Translational Medicine, suggests that the drug's dual effect is based on a fundamental difference between the ability of cancer cells and healthy cells to withstand the damaging effects of a highly reactive molecule called hydrogen peroxide, which is produced during the dismutation of superoxide.
The drug, known as Avasopasem manganese, is made by Galera Therapeutics. ...
