Nav: Home

Calculating recharge of groundwater more precisely

February 28, 2017

An international team of researchers has demonstrated that key processes in models used for the global assessment of water resources for climate change are currently missing. This could mean climate change impact models are wrong in some parts of the world and cannot yet be used to guide water management.

The study, published today [Tuesday 28 February] in the Proceedings of the National Academy of Sciences (PNAS), has shown that groundwater recharge estimates for 560 million people in the karst regions in Europe, the Middle East and Northern Africa, are much higher than previously estimated from current large-scale models.

This finding, by researchers from the Universities of Bristol; Freiburg; Victoria, Canada; and the International Institute for Applied Systems Analysis, Austria, suggests that more work is needed to ensure sufficient realism in large-scale hydrologic models before they can be reliably used for local water management.

Groundwater is a vital resource in many regions around the globe. Groundwater recharge rate is an important quantity for securing sustainable supplies when managing drinking and irrigation water.

The researchers compared two hydrological models that simulate groundwater recharge over large regions. One is a well-established global model with limited accounting for subsurface heterogeneity. The other is a continental model the researchers have recently developed and which includes, for example, the variability in the thickness of soils and different subsurface permeabilities.

The research team carried out the comparison for all of the karst regions in Europe, North Africa and the Middle East. Karst regions are known for their great degree of subsurface heterogeneity, because carbonate rock shows greater susceptibility to chemical weathering - a process that is known as karstification.

Karstification leads to varying soil depths and permeabilities. A comparison of the models' calculations with independent observations of groundwater recharge at 38 sites in the regions has shown that the model that accounts for heterogeneity produces more realistic estimates.

The researchers have demonstrated the reason for the difference between the two models. In its simulations, their newly developed model shows reduced fractions of surface runoff and evaporation -- and consequently, greater groundwater recharge. According to the new model, a farmer in the Mediterranean region would potentially have significantly more groundwater available for extraction than current large-scale models predict.

Thorsten Wagener, Professor of Water and Environmental Engineering in the Department of Civil Engineering at the University of Bristol and one of the researchers on the study team, said: "When applied to the example of karst regions, our approach shows how it is possible to adapt global models used to predict water shortages, drought or floods to account more realistically for regional conditions. This approach will ultimately enable both local management and large-scale assessments within the same model."

A study recently published in PNAS suggests that inclusion of currently missing key hydrological processes in large-scale climate change impact models can significantly alter our estimates of water availability.
-end-
Paper:

"Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity" by Hartmann et al is published in Proceedings of the National Academy of Sciences (PNAS)

University of Bristol

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...