WAY is a coalition of stakeholders being innovative leaders encouraging watershed-based planning, restoration and protection in York County, Pennsylvania, and beyond.

Monday, August 18, 2014

Public Misperception of Quiescent Mill Ponds

Sunday's York Daily News contained an excellent article "Fix PA's Killer Dams", by Scott Fisher, Editor, about the dangers.

However, one reader commented that "The dam appeals to me, recalling a recent kayak paddle miles upstream and saying he has caught large fish in the pools created by the dam. If the dam(s) were removed, we'd end up with a shallow, rocky creek that would be useless for such activities."

The public maintains the misperception that these quiescent mill pond settings are both normal and healthy ecosystems. I argue they are not. Dams of all sizes are the direct result of the loss of migrating American shad, Atlantic eels, numerous freshwater shellfish, and other migratory species.

Impoundments behind dams often have poor water quality and may not have the quantity and diversity of aquatic species often found in a free-flowing river. Typically, the tail-water runs approximately one to two miles upstream of these dams.

Removing dams brings different ecological benefits, including restoring free-flowing rivers, enabling unobstructed fish passage, and improving water quality (Scruton et al., 1998; Bednarek, 2001). Bednarek (2001) reviewed the long-term and short-term ecological impacts of dam removal based on 16 dams. She concluded that biotic diversity could increase by removing the dams and that the increased sediment load was a short-term effect. Scruton et al. (1998) showed an 18-fold increase in biomass of juvenile salmon and trout, a result of a 62% habitat increase after removing some dams.

Removing these dams in York County have shown immediate improvements in water quality and diversity of aquatic species often found in a free-flowing river, as well as eliminating a public health and safety hazard.

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