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Climate change shocks Georgia’s rivers

November 17, 2014

Why should Georgia citizens be concerned about the impacts of global climate change?  The National Climate Assessment reports that global climate change is responsible for changes in precipitation patterns, rising sea levels, more acidic oceans, and increased frequency of extreme “weather whiplash.” In Georgia, changes in precipitation patterns are leading to decreased river flows, and rising sea levels are causing accelerated intrusion of saltwater into freshwater wetlands, streams and rivers. Moreover, stream and river temperatures are increasing in Georgia.

Climate change is affecting precipitation patterns that directly affect Georgia’s rivers. According to Aris Georgakakos, director of the Georgia Water Resources Institute at Georgia Tech, river flows in Georgia are decreasing as a result of changing rainfall patterns. Specifically, Georgia is seeing short periods of heavy rain and long periods of drought. Since big flows from heavy rains occur infrequently and dissipate quickly, Georgia’s rivers are left thirsty most of the time with low flows. The National Climate Assessment indicates that this pattern of lower flows under drought conditions and higher flows during floods can worsen water quality.

Professor Georgakakos’s study of the Oconee River indicates that the amount of water flowing down the Oconee River has declined approximately 50 percent over the last half-century. University of Georgia professor Todd Rasmussen and colleagues analyzed river flow statistics for the Middle Oconee River. They found that approximately 90 percent of the river’s record low flows have been recorded in the last 10 years. Moreover, U.S. Geological Survey statistics indicate that annual river flow in the Oconee River was the lowest ever recorded in 2012.

In addition to changing precipitation patterns, rising sea levels pose significant risk to Georgia’s freshwater resources with respect to drinking water supply, ecosystem habitat, and agriculture. According to the National Climate Assessment, higher sea levels along the East coast “will accelerate saltwater intrusion into freshwater supplies from rivers, streams, and groundwater sources near the coast.” The U.S. Environmental Protection Agency (EPA) points out that the intrusion of saltwater into freshwater areas may increase the need for desalination for coastal freshwater aquifers that supply drinking water. In addition to affecting drinking water supply, the intrusion of saltwater into freshwater areas “can physiologically stress microorganisms, plants, and animals and alter metabolic pathways, rates of activity, and abundance,” according to research conducted by the Department of Marine Sciences at the University of Georgia. Moreover, as the National Climate Assessment notes, sea level rise may lead to changes in salinity and water levels at such a fast rate that local vegetation is unable to adapt quickly enough and these areas become open water.

Saltwater intrusion, in response to sea level rise, not only affects drinking water supply and ecosystem habitat, but it also affects the agriculture sector. The National Climate Assessment points out that the intrusion of saltwater into freshwater resources may “reduce the availability of fresh surface and groundwater for irrigation, thereby limiting crop production in some areas.”

Research published by the Ecological Society of America (ESA) indicates that Georgia’s rivers are getting warmer. The ESA specifically found a significant increase in water temperature in the Coosa River and Conasauga River. According to the EPA, increased river temperatures can harm aquatic organisms that live in cold-water habitats, leading to the extinction of local species. Additionally, warmer water in rivers can facilitate the invasion of non-native species, which often prey on and out-compete the native species for food, leading the native species population to suffer.

What can Georgia do to adapt to changing precipitation patterns and rising sea levels?  Scientific research indicates that Georgia’s rivers and streams are suffering from changing precipitating patterns and warming water temperatures. Moreover, rising sea levels raise concerns that saltwater will intrude into freshwater streams and rivers near the coast. Unfortunately, many federal policies do not require adaptive planning for sea level rise and coastal flooding. So, what can state and local governments do to better adapt to these significant changes?

Local governments, like the City of Tybee Island, are beginning to prepare for the changes in precipitation patterns and rising sea levels by adopting methods of adaptation. A report recently published by the Union of Concerned Scientists (UCS), entitled “Encroaching Tides,” discusses methods for adapting to climate change along Georgia’s coast. In its report, UCS mentions measures being adopted by the City of Tybee Island to address the effects of climate change. Tybee Island is Georgia’s most densely developed barrier island and a popular tourist destination that faces erosion and coastal flooding as sea level rises. For example, the Island has suffered severe sewer backups when rain and high tide occur simultaneously. To prevent sea water from flowing into the City’s sewer system during future rain/high tide events, Tybee Island has installed large diameter pipes with tide gates. See the UCS’s full report for more information.

To address sewage backup and other issues associated with sea level rise, the City of Tybee Island has collaborated with Georgia Sea Grant and the Carl Vinson Institute of Government to develop a Sea Level Rise Adaptation Plan (the “Plan”). In August 2012, the Tybee Island City Council held townhall meetings to identify adaptation actions for the Plan. The City’s adaptation actions include retrofitting the stormwater sewage system, elevating well pumps, considering innovative methods to deal with Repetitive Loss Properties, working with Georgia Department of Transportation on potential options for elevating U.S. Highway 80 several feet above its current grade, increasing nourishment of the beach, and discussing novel approaches for stabilizing shorelines. Following identification of these adaptation actions, Georgia Sea Grant and the Carl Vinson Institute of Government conducted a cost-benefit analysis that weighs these actions over a 50-year planning horizon.

Georgia’s rivers are already being impacted by climate change, but Georgia has the opportunity to make smarter choices when it comes to energy production and coastal resiliency.  These choices will reduce the impacts that climate change will have on the state’s rivers going forward. The science clearly demonstrates that the release of carbon dioxide and other greenhouse gases, the majority of which come from the burning of fossil fuels, into the atmosphere is causing temperatures to rise. In recent years, Georgia has begun retiring dirty coal-fired power plants to reduce its emissions of greenhouse gases into the atmosphere. Georgia should take advantage of these retirement efforts by increasing the use of solar power to satisfy energy production. By relying less on the burning of fossil fuels to produce energy and focusing more on producing energy through solar power, Georgia can reduce its contribution of greenhouse gases into the atmosphere. In doing so, Georgia can help arrest climate change and reduce the threat of future impacts on the state’s rivers.

-Hunter Jones

4 Comments leave one →
  1. Wodamark permalink
    November 18, 2014 2:43 pm

    “Research published by the Ecological Society of America (ESA) indicates that Georgia’s rivers are getting warmer. The ESA specifically found a significant increase in water temperature in the Coosa River and Conasauga River”

    Actually no significant temperature increase was found for these two rivers – the P for them was >0.05. Look at Table 1 and the explanation in the “Results” paragraph on the preceding page

  2. December 3, 2014 11:01 am

    Quite frankly climate change is a sham and a scam.
    I have been taking temperatures for years and watching sea levels at the coast and there has been no change in ten years.
    The level of water in rivers rises or falls according to drought or flood but remains the same on average.
    The ocean is not rising at the places I visit nor is it falling.
    Climate change is a government backed way to tax and take money, change lifestyles and scare the public.
    Much as the old Aztecs ripped out human hearts to bring rain or stop an eclipse.
    Just so much of a social engineering con.
    The rivers are not getting warmer nor colder.

  3. December 3, 2014 1:36 pm

    As a retired scientist I accept the theories and current facts related to global warming. And no matter what measures we take to alter the chemical and physical ramifications it will eventually have on our planet, I believe it can only (maybe) be altered by drastic measures.
    Specifically, by reducing the human population on the Earth. When I was born it measured about 2 billion souls, very soon it will rise to 8 billion and climbing. How to reduce population is a touchy issue of course, and I don’t see religion or politics leading the effort, and I am aghast at war, disease, or toxic wastes solving the problem. So Mankind has an interesting future. It is not at all impossible that Homo sapiens could be the greatest and shortest-lived species in our planets history to date.

  4. December 18, 2014 10:31 am

    CLARIFICATION: The increase in the water temperature for the Coosa and Conasauga Rivers is not “a significant linear increase.” ESA data does indicate a “rate of increase” in water temperatures in the Coosa and Conasauga Rivers.

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