Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Large Dams Can Affect Local Climates, Alter Rainfall

10.02.2011
Researchers investigating how large dams can affect local climates say dams have the clear potential to drastically alter local rainfall in some regions.

A study by researchers at Tennessee Tech University, Purdue University, the University of Colorado and the University of Georgia, Pacific Northwest National Laboratory and Hellenic Center for Marine Research concluded that artificial reservoirs can modify precipitation patterns.

The study -published in Geophysical Research Letters— marks the first time researchers have documented large dams having a clear, strong influence on the climate around artificial reservoirs, an influence markedly different from the climate around natural lakes and wetlands.

The results should spur consideration of more robust management of dams and set the stage for further research on the regions and climates to focus on, says Faisal Hossain, Tennessee Tech University civil engineering professor.

“This research shows you the smoking gun,” said Hossain. “Logically and physically we knew it was possible that a having a large body of water and spreading it around would change the local climate. Now, our results give us a better idea of which dams are most likely to gradually change local climate and what that means for managing those reservoirs as time passes.”

With Hossain and TTU doctoral student Ahmed Mohamed Degu leading the study, the research team looked at 30 years of climate data based on a technique commonly known as reanalysis in the scientific community. Reanalysis aims to recreate the gold standard record of weather conditions everywhere in a domain by using as much information in hindsight as possible. The data used spanned from 1979-2009 and was collected 24/7 over North America.

Roger Pielke Sr. of the University of Colorado’s Cooperative Institute for Research in Environmental Sciences says the work was a breakthrough study in scope and mission.

“This is a critically important, much needed study with multiple authors and institutions using diverse data sets in order to obtain information on how dams and their surroundings affect the region's climate rather than a local snapshot that may not be representative for larger areas,” said Pielke.

The study reports that large dams influence local climate most in the Mediterranean and semi-arid climates such as ones in California and in the Southwestern United States.

So how does a large dam and its reservoir alter the climate? If the dam’s reservoir is large enough or if the water is spread around by uses such as extensive irrigation or recreational activities, then the expanded distribution of water creates an altered climate because it allows the water to evaporate more easily.

“Think of your typical backyard swimming pool,” said Hossain.

“If you pumped all the water out of your swimming pool and spread it onto your lawn, it wouldn’t take long for all that water to evaporate.”

A change in water available for evaporation can change humidity, energy and surface temperature and affect the climate around a reservoir. Under the right circumstances, all of these play an important role in changing rainfall.

“We now know we need to do better building and managing dams and reservoirs in those arid and Mediterranean regions where water is really scarce,” said Hossain.

Hossain says the report reflects a changing mindset in this area of research.
“We know a lot about how climate change affects reservoirs, but what we didn’t know a lot about was what a reservoir could do to the local climate,” he said. “We just reversed our thinking by saying that a reservoir and the activities it supports are just as important a player for climate as the larger climate is for the reservoir. Basically, it’s a two-way street.”

Pielke says this framework, known as a vulnerability framework, is more inclusive and promotes more effective decisions.

“The change in mindset is to identify the vulnerabilities from a bottom-up resource-based perspective,” said Pielke.

Hossain agrees that this perspective changes the way civil engineers think in the classroom and on the job.

“Our profession generally has never looked at climate and what we do to it once we build large structures like dams, even cities, parks, ports, etc.,” said Hossain. “That work is missing at the interface of our profession.

“We now need to adapt, be more climate cognizant and broaden our horizons. Many of our dams in the U.S. are 50 years old and we need answers for the future,” he said.

“Now we have a better idea about how the local climate and rainfall may change than we did 50 years ago, although more work is needed to pinpoint exact causes at each dam location,” said Hossain. Nevertheless, we now can consider different scenarios and do a life cycle assessment before even building a dam.

“This is like saying we can now forecast what a dam may do to itself as it ages before even building it; then we build it according to a specification that the profession is prepared for,” he concluded.

The work was mainly supported by TTU’s Office of Research and the Center for the Management, Utilization and Protection of Water Resources.

Faisal Hossain, fhossain@tntech.edu
Office: 931-372-3257
Cell: 931-239-4665
Media contact: Karen Lykins, 931-372-3084, klykins@tntech.edu

Karen Lykins | Newswise Science News
Further information:
http://www.tntech.edu

More articles from Earth Sciences:

nachricht Arctic melt ponds form when meltwater clogs ice pores
24.01.2017 | University of Utah

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>