Low dams being removed, modified

DAYTON - Ohio and other states are removing or modifying many low dams, blamed
for drownings from the churning the structures create in the water.

Craig and Patricia Wenner drowned after jumping into the Stillwater River near a
low dam in suburban Englewood on Dec. 25. Mrs. Wenner was trying to save the
couple's dog, which had become trapped in the dam's churn.

A proposal to remove the dam by 2008 - planned before the drownings - is
awaiting regulatory approval.

The Yorkville, Ill., low dam, a 5-foot-high structure that spans the Fox River
west of Chicago, is being modified for safety and recreation.

In the past 25 years, 18 people have drowned at or near the dam, police say.
Last summer, three died when two men tried to save another who had taken his
kayak over the dam and became trapped in the dam's boil.

The dams were once considered a good way to slow river flow and create still
pools on one side, but they result in swirling water on the other side that has
trapped people.

Water flowing over the top of the dams forms what's called a hole, or hydraulic,
at the base that traps objects. The current forces a victim underwater, pushed
away from the dam, then circulated to the top where the cycle repeats. It is
nearly impossible to escape.

Besides posing deadly hazards, low dams block the movement of fish and the
propagation of endangered fresh water mussels, both key factors in waterway
health.

Ohio defines low heads as dams less than 15 feet high and built from timber,
stone or concrete from bank to bank.

The Ohio Department of Natural Resources has had a policy since 1973 to remove
outdated dams that no longer serve a purpose. Since 1999, eight have been
removed.

Nationwide, 49 dams - many of them low dams - were scheduled for removal in 2006
in California, Connecticut, Massachusetts, Maryland, Maine, Michigan,
Pennsylvania and other states, according to American Rivers, a Washington-based
nonprofit that pushes for restoring natural waterway flows.

The organization has helped remove more than 50 in Pennsylvania in the past
three years, said Stephanie Lindloff, director of the Restoring Rivers
Initiative.

National estimates on the number of low dams in the U.S. start at 99,000 and
extend to 2.5 million, said Laura Wildman, director of river science for
American Rivers.

In Yorkville, workers have terraced the dam with an underwater staircase to try
to make it survivable for anyone who goes over it. Plans would add a canoe
channel and fish ladder.

Along Buck Creek in Springfield, Ohio, four low dams are being considered for
removal. They would be replaced with boulders to create pools and rapids for
paddling sports, said Charles Swaney, secretary treasurer of the Springfield
Conservancy District.

Publication date: 02-07-2007

http://news.cincypost.com/apps/pbcs....WS01/702070382

Per Garrison Hilliard:
DAYTON - Ohio and other states are removing or modifying many low dams, blamed
for drownings from the churning the structures create in the water.

We have quite a few of them here in SE Penna where I ride my bike - especially
along the Perkiomen creek.

Every one seems to have at least one little monument near it to somebody that
drowned there.

Erie thing to me is that they look like *nothing*.... no apparent hazard at all.
If I didn't know better, I wouldn't hesitate to in the water on or under one of
those little spillways.
--
PeteCresswell