- Associated Press - Wednesday, August 20, 2014

Editorials from around Pennsylvania

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FIX PENNSYLVANIA’S KILLER DAMS

… With more than 70 fatalities, Pennsylvania has suffered the highest number of dam drownings in the United States, according to data compiled by Brigham Young University.

One-third of the documented low-head dam fatalities in the United States have occurred in Pennsylvania, Minnesota and Iowa, according Bruce Tschantz, a professor of engineering at the University of Tennessee-Knoxville who maintains the safedam.com website.

Pennsylvania has many stream miles dotted with low-head dams, most built in the 1800s to power mills. According to a July presentation by Ben Lorson, a biologist with the Pennsylvania Fish and Boat Commission, the state’s inventory lists about 3,000 dams - but he noted that there are more that have not been logged.

Tschantz said dam danger can be deceptive because small changes in water flow can dramatically increase risk. One day, a swimmer might easily escape the downstream boil. The next day, after a rain (even far upstream), the same person could be trapped by the hydraulic jump and be unable to escape. The bubbles created by the water falling over the crest of the dam elevate the risk. The oxygen in the water reduces a person’s buoyancy, so even wearing a life vest is no guarantee of escape. …

According to Lorson, more than 230 dams have been removed in Pennsylvania since 1995. … Lorson said Pennsylvania has been a national leader in removal of obsolete dams, spending about $4.5 million on such projects since 2011.

But removal efforts have been dammed up and slowed to a trickle since the peak year of 2007, when 32 were removed in the state. Since 2008, when the recession hit, removals have dropped from 30 that year to 10 in 2011. In 2012, 11 dams were removed, and 13 were breached in 2013. …

What if there were a way to reduce the dangers of low-head dams without removing them and changing the landscape?

There is.

It’s a method largely pioneered by Luther Aadland, a river ecologist with the Department of Natural Resources in Minnesota, which has suffered nearly as many low-head dam drownings as Pennsylvania.

Aadland and others have come up with a method of retrofitting low-head dams to eliminate the hydraulic vortex, and it’s remarkably simple:

Rocks.

Stones.

Story Continues →