Wandering the towpath (student guest posts)

The Lehigh Canal was built in 1827 to transport coal from the upper Lehigh Valley.  The canal was in operation until the 1940s, and it is now primarily used as a recreational trail for hiking, walking, and biking.  Within the Bethlehem-Allentown-Easton area, it has all the problems of an isolated natural area surrounded by development (habitat degradation, invasive species, eutrophication of the canal), not to mention the legacies of once being a transportation corridor (e.g., even more invasive species).  However, regardless of these problems, the area still provides considerable ecosystem services, including recreational opportunities, a great path for carbon-neutral commuting to work (for me!), and an easily accessible place to observe nature within the greater Bethlehem area.

The towpath between the Lehigh River and Canal. This picture taken between Bethlehem and Freemansburg (Photo: RK Booth).

Below are a few observations, made by students along the towpath this semester…highlighting the educational value of this interesting legacy of Lehigh Valley history.


The restoration effort at Sand Island. Coconut husk has been spread over the river bank to slow erosion while the native plant species get established. (Photo: Alexandria Kennedy)

Restoration at Sand Island

Last weekend, Dennis Scholl of the Delaware and Lehigh National Heritage Corridor led a group of volunteers in an effort to replant native species along the canal just east of Sand Island in Bethlehem, PA.  I spent many hours of my youth exploring this area, visiting the playground, walking the bridge, and returning via the towpath adjacent to the canal. The area, and particularly the banks of the canal and river, were thick with vegetation.   Although located in the center of the city of Bethlehem, as a child I really believed that we were walking deep in a magical forest.  However, a few years ago most understory vegetation was cleared, giving it the appearance of a park. You could see through the trees all the way to the streets of Bethlehem. Of course, the intentions of this work were good – much of the understory vegetation was composed of invasive species, and native species were extensively planted in their place – but a lot bare ground remained. However, the removal of the vegetation didn’t just change the appearance of the area; without the thick vegetation the area became vulnerable to increased erosion, which was made worse by the unusual rain and flooding of last year.   I hope the new restoration effort succeeds in reintroducing local plants to all of the areas of Sand Island, turning it back into a magical forest in the middle of the city of Bethlehem.



A fish ladder on the chain dam! (Photo: Ashley Kreitz)

Fish Ladder!

As I was on a bike ride near the Lehigh River, I came across something that we had just discussed in class –  a fish ladder!  To me, the ladder looked like a very difficult maze for the fish to navigate. The dam was originally constructed to help boats cross the river and was called the chain dam because there was a link chain across the river to prevent boats from falling over the edge of the dam. The entrance to the ladder was surprising small – only 2 meters or so wide. It is hard to believe that a fish could find it, let alone actually decide to enter it.

Apparently the ladder was added to the dam in 1992. One year fish tallies were made to assess how many fish actually use the ladder.  645 fish made it up the ladder from March 31-June 7. The tallies were achieved by using cameras that recorded the ladder 24 hours a day. The tapes were then looked through by interns, and the fish were each counted.  Must have been about as exciting as counting sheep.

The Chain Dam. (Photo: Ashley Kreitz)

I observed a fish or possibly an eel that seemed to be stuck to one of the concrete walls. I wonder how many fish die in the ladder each year, or from injuries sustained while trying to navigate the maze? Perhaps another job for the interns….



A painted turtle is a common sighting in the Lehigh Canal. (Photo: wikipedia)

Turtles, Turtles, and More Turtles

Today after class, I went for a run on the canal path.  Usually I don’t pay much attention, but today I happened to look into the canal and saw a painted turtle basking in the sun!  I continued to look for them while I ran.  I saw another immediately…and then another right after!  So I decided to count and by the end of my run I had seen 36 turtles!   I have always assumed that the murky, algae-covered waters of the canal couldn’t possibly contain any life besides some bottom feeders.  However, after a little research I discovered that painted turtles are extremely common in Pennsylvania, and they prefer slow-moving water and ditches where algae and insects are abundant.  So in contrast to what I had thought, the canal is probably really good habitat for them.



Posted on April 26, 2012, in Conservation & Biodiversity (EES-28), Student Guest Posts and tagged , , , , , , . Bookmark the permalink. Leave a comment.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: