Analysis: New global warming culprit: Methane emissions jump dramatically during dam draw-downs
Kendall Moyer
https://www.sciencedaily.com/releases/2012/08/120808081420.htm
Researchers from Washing State University have discovered some shocking data involving dams. In a study of the water reservoirs behind dams, and the effect of water levels rising and falling, researchers found that methane levels jump 20- and 36- fold during draw-downs. One researcher measured dissolved gases in the water column of Lacamas Lake in Clark County and found that methane emissions jumped 20-fold when the water level was drawn down. A fellow researcher who sampled bubbles rising from the lake mud found a 36-fold increase in methane during a draw-down. This Washington State University research team is actually the first to demonstrate and quantify the relationship between water-level draw-downs and greenhouse gas releases.
While reservoirs have typically been considered a green energy choice, their role in greenhouse gas emissions and the subsequent global warming have been overlooked. Because of this, there are some 80,000 dams in the United States alone. These dams harbor biological activity that can produce massive amounts of greenhouse gases, much of it methane. Methane is twenty-five times more effective than carbon dioxide at trapping heat in the atmosphere. Emissions may be higher in summer months, when warmer temperatures and low oxygen conditions in bottom waters stimulate the microbial activity that produces greenhouse gases.
One suggested result of the research is to manage draw-downs differently. The timing, magnitude and speed of reservoir draw-downs can be controlled, and all of these affect how much methane gets released into the atmosphere. When removing a dam completely, the optimal time do so may be considered when looking at ways to cut down on greenhouse gases. Removing a dam releases greenhouse gases, but this is a one-time occurrence, while continuing the use of the reservoir creates regular emissions that correlate with regular draw-downs. The research of this article is summarized in such a way that lets the reader know that this is an issue that scientists do not know enough about yet. Clearly, continued studies are necessary to discover the ways that draw-downs affect climate change. Future actions must be taken to either reduce the emissions created by dams, or to educate the public on why they should not accept dams as a green alternative energy source to begin with.
To me, this article says a lot about how we implement “green” alternative energy before we really are aware of the consequences. Dams have been so widely accepted as a good, clean, environmentally friendly energy source, and because of this, they have been widely implemented all over the world. It is only now, after we already have the infrastructure for such a large number of dams in place, that we are beginning to study and realize the harmful effects of dams. At this point, the general public has so widely accepted that dams are a good source of energy, that as the new data comes out and provides evidence that the opposite is true, it will be an upstream battle to educate and convince the masses of this. However, that education of citizens will be vital if we are to create enough public outcry against the use of dams and the creation of new ones to make the government take a second look at dams as an energy source, and possibly move on to other sources, such as wind and solar energy.
This peer reviewed article gives good insight into the research that is just beginning, and the large amount of research that needs to be done on dams. The author does a good job at providing possible solutions, or at least partial solutions to the issue, while making it clear that more data needs to be collected before the best solution can be presented.
