Sunday, April 9, 2006

Dam removal is right course for stream, groups say

By CHRIS A. COUROGEN

For much of the last century, the dam across the Yellow Breeches Creek at Spangler's Mill was a source of power.

Water diverted by the dam flowed through a millrace, powering the Spangler Flour Co.'s gristmill and an adjacent sawmill.

The scene repeats itself along the nearly 50 miles of the stream, popular for its trout fishing, that winds its way from the headwaters near Walnut Bottom to the Susquehanna River near New Cumberland.

At one time, as many as 18 dams dotted the Yellow Breeches, nearly all built to power mills.

None of those mills operates, but more than half of them remain, relics that serve no purpose and provide no value beyond the aesthetics of the waterfalls they create.

In most cases, the dams are more of a liability than an asset for a waterway considered to be one of the top trout fisheries in the state. They are dangers to those who swim near them, impediments to fish trying to migrate upstream and canoeists trying to paddle downstream, and detriments to the ecological balance of the creek.

That is why a coalition of environmental groups and governmental entities is working to remove many of them.

"In an ideal world, the Yellow Breeches moving without obstruction would be best for the ecology of the stream," said Mark Pennell, an engineer with URS, one of the leading dam-removal companies in the nation. Pennell has engineered more than 30 dam removals around the state.

Dam removal's benefits

It is unlikely all of the dams will be removed. Two serve as impoundments for two water companies that supply much of the West Shore with drinking water. Others might have owners who do not want them removed. Dam-removal efforts in Pennsylvania are voluntary.

In many cases, property owners find that removing a dam makes sense economically and ecologically.

The Whittlinger Dam is an example. Partially breached by flooding in 1993, it was in disrepair when the Audubon Society gave the deed for 60 acres around the dam to South Middleton Twp. in 1996 for use as a nature preserve and park.

An engineering report in 2003 estimated the cost of repairing the dam at more than $1 million. That same report said it would cost almost as much to remove the dam.

The township looked at building a rock weir to lessen the dangers of the undertow at the dam's base, and it seemed to be the most economical solution at a price of about $100,000.

Then two environmental groups, American Rivers and Trout Unlimited, stepped forward.

"Their engineers estimated it could be removed for around $50,000," South Middleton Twp. engineer Brian O'Neil said. The two groups also told the township about grants that might be available to fund the project.

The Pennsylvania Fish and Boat Commission, for example, provides technical expertise and money for the removal of dams.

"They get rid of liability concerns and we get to restore the stream habitat," said Scott Carney, chief of the Fish and Boat Commission's Division of Habitat Management.

Enhancing recreation

Removing dams helps cool the stream, an essential element of a healthy trout habitat. The faster-flowing water also washes out sediment that covers the bottom of dam impoundments, exposing the coarse, rocky stream bottom that is home to the aquatic life that makes up most of a trout's diet. Those same coarse stream bottoms are also where trout deposit eggs when spawning, improving the natural reproduction of the fish and reducing the need for stocking.

Migratory fish such as shad, eels and herring could also return to the stream if dams are removed and fish passages built at those that remain.

The benefits are not limited to fish. Dams force streams to widen, undercutting banks, killing vegetation and increasing erosion. They allow for buildups of excess nutrients, resulting in an overabundance of underwater plants that eliminate oxygen from the water.

Dams also increase the potential for flooding by keeping the banks of the stream artificially full, lessening the stream's capacity to store runoff.

There are also recreational benefits to dam removal.

Members of the Canoe Club of Greater Harrisburg are raving about the improvements brought by the removal of Hoffman Dam. On the club's first spring paddle of the year, members marveled at the improved flow in the area once impounded by the dam.

"We used to have to end our trips there and carry our boats over 100 yards up a hill to reach our cars. Without the dam, it adds almost another hour of good paddling without having to portage around the dam," Len Neidig, a club member, said.

The removal of other dams would enhance the proposed Yellow Breeches Water Trail, a plan in the works by the Yellow Breeches Watershed Association and the Cumberland County Planning Commission. Maps for the proposed trail show the stream divided into three paddle trips.

Stephanie Williams, the county's Greenway and Open Space Coordinator, said she hopes a combination of dam removals and portage easements will allow paddlers to "put in at Mount Holly Springs and travel all the way to the Susquehanna River."

That goal is a ways off. Williams said three other dams along the stream have been identified as targets for removal. But Carney said not all dam owners along the stream are ready to sign up for removal programs.

"A lot of it is a lack of understanding of the benefits," Carney said.

"We may have to do a few of these projects to demonstrate before we can get a buy-in from some of the owners."

Tom Baltz of Trout Unlimited remains hopeful for the long-term success of dam-removal efforts.

"We are working toward the health of the stream. The dams inhibit the health of the stream," he said.

CHRIS A. COUROGEN: 975-9784 or ccourogen@patriot-news.com