Some well-known dams on Little Lehigh and Jordan creeks will be removed this summer by Wildlands Conservancy.
They include the Robin Hood dam in Allentown’s Lehigh Parkway and another in the city’s Jordan Park, as well as the dam over Jordan Creek dam next to MacArthur Road in Whitehall Township.
A total of nine dams will be removed.
The conservancy will restore free-flowing conditions to more than 15 miles of the two streams, improving their environmental health.
"We’re bringing back a natural stream system," said Kristie Fach, director of ecological restoration at the conservancy. "It’s been over a century since these streams have been flowing freely."
She said this summer's work will be the biggest dam removal project ever done in this area.
Five of the doomed dams are on the Little Lehigh –three of them in Lehigh Parkway -- and are four on the Jordan. The two streams converge in Allentown, not far from where the Little Lehigh flows into the Lehigh River.
Fach refers to the Jordan as a tributary of the Little Lehigh, which is why the dam removal project is called the Little Lehigh Creek Watershed Restoration Project.
Not every dam will be removed from the two streams. The Fountain Park dam that spans the Little Lehigh between 8th and 10th streets in Allentown will remain. It is needed because the city draws drinking water from the creek just upstream from that dam. If the dam was removed, the water intakes in the stream might not work, said Fach.
The Fountain Park dam is one of only two dams that will remain on the lower Little Lehigh.
The conservancy still is negotiating with two private property owners to remove another Little Lehigh dam less than two miles downstream from the Wildlands Conservancy’s offices right outside Emmaus. Fach said that concrete and rock dam already is partially breached.
She said someday the conservancy would love to remove all dams on both streams. "We started downstream, closest to the Lehigh River. We'll keep working upstream to the next dam, as long as there is one."
The conservancy won’t just tear out the dams and walk away. In the summer of 2014, stream banks at the dam sites will be graded and trees and other vegetation will be planted on the restored banks, to prevent future erosion and provide more habitat for birds and other wildlife. Small structures also will be placed in the streams to improve fish habitat.
Fach said the $431,000 project began nearly five years ago. It involved getting permission from property owners, as well as obtaining state approvals and funding.
The smallest dam that will be removed is on the Little Lehigh just below the Wild Cherry Lane bridge in Lower Macungie Township. It is on land owned by the township. On April 4, in response to a letter from Fach, Lower Macungie commissioners unanimously voted to have that dam removed.
The other four Little Lehigh dams being removed are farther downstream. One is privately-owned, but just across the stream from the Conservancy’s Pool Wildlife Sanctuary on the Emmaus/Lower Macungie boundary.
The Lehigh Parkway dams are near Keystone Road, at Fish Hatchery Road near the trout nursery and at the popular Robin Hood picnic area.
In addition to removing the Jordan Park dam in Allentown and the nearby MacArthur Road dam in Whitehall, a third Jordan Creek dam will be removed just downstream from the Route 22 overpass. The fourth to be removed is along Mickley Road near Helfrich Springs in Whitehall.
Fach said all four of those dams are on publicly-owned land. The three in Whitehall are within the Jordan Park Greenway.
After the four dams are removed, Jordan Creek will be free-flowing for about nine miles – from the point where it flows into the Little Lehigh all the way up to a dam near where it flows under Cedar Crest Boulevard, according to Fach.
Some of the dams were built to serve water-powered mills and Facht said others may have just been built for esthetic reasons, to create swimming holes or so farmers could water their livestock. No one knows why some were built.
What’s wrong with dams? They prevent sediment from flowing downstream, so silt piles up behind them. The water becomes shallow, warm and slow-moving -- producing less oxygen for fish. Accumulating silt buries eggs laid by fish, preventing them from hatching. It also buries insect eggs, which reduces the food supply for fish.
You might think dams create good fishing holes, but Fach said streams immediately above dams are aquatic deserts, with very little fish life.
The Little Lehigh is a very popular high-quality trout fishing stream and trout need cold water to sustain a breeding population, explained Scott Alderfer, conservation chairman for the Little Lehigh chapter of Trout Unlimited.
He explained the spring-fed stream maintains a year-round water temperature of about 55 degrees, but its water gets too warm above a dam.
Alderfer also is chairman of the Lower Macungie Advisory Council. He described the Little Lehigh as Lower Macungie’s spine, saying it flows from one end of the township to the other. He suggested that Lower Macungie work with Wildlands Conservancy to remove the Wild Cherry Lane dam, which he called a bottleneck that increases upstream flooding.
Fach said removing dams reduces flooding. She explained a stream above a dam already is close to the top of its banks. When heavy rains come, those streams go over their banks.
Dams also are attractive nuisances that create public safety issues. She said property owners may be responsible if someone gets hurt. Not only can people slip on algae-covered concrete, but the force of water going over even a small dam can knock them down. Fach said unsuspecting rafters on the Little Lehigh have gone over dams. A dog recently drowned in the dam at Jordan Park in Allentown.
Facht also said dams don’t last forever, adding property owners face large bills if they have to remove a breached or damaged dam from a stream.
Removing dams and planting buffers of vegetation along streams discourages large flocks of geese that now land on pond-like surfaces above dams and waddle across adjoining lawns, creating concentrations of droppings that add too much nutrient to slow-moving water, causing more algae to grow.
Fach said Moravian College students have monitored the health of the two streams above the dams, checking factors such as water temperature, oxygen levels and fish counts. Moravian students will do comparative monitoring after the dams are removed and the banks have been restored and planted.
Most of the money for the watershed restoration project --$331,000 -- came from the state Department of Environmental Protection. Another $75,000 was provided by FishAmerica Foundation and $25,000 came from American Rivers.
Fach said a dam owned by Wildlands Conservancy at its Pool Wildlife Sanctuary was one of the first removed in Pennsylvania when it was taken out in 2000. She said the conservancy also removed three dams from Allentown’s Trout Creek two years ago.