Friday, August 31, 2012

Downstream, Part 1

Harper's Run, a tributary in the county park.  I've featured this stream many times, but this may be my first summer image.
A week ago last Saturday (August 25), Kali and I made a six-mile loop hike along the creek downstream of "our" preserve.  Two miles downstream of the southern preserve boundary, the creek flows into a county park, and then on into a Philadelphia city park on its way to its mouth at the Delaware River.  We parked in the county park and walked the streamside path downstream into the city.  Once the creek crosses the city line, it is bordered by two paths, a dirt footpath on its east bank, and a paved bicycle path along its west bank.  We decided to walk the dirt footpath downstream, cross a bridge, and return upstream on the paved bike path.  I'm going to divide my account and pictures into two parts: the views from our walk downstream first, followed by a second post recounting our walk back to the car.  

A beautiful mature oak near Harper's Run; alas, not long for this world.
An old oak alongside the dirt footpath in the Philadelphia city park
Waiting for Scott to take yet another picture
Scarred and abused - oh so typical in the city park
Healing below the graffiti line
The inhabitant was perched at the mouth of the web, but ran for cover when I stopped to capture its image
Feather of a Downy or Hairy Woodpecker (Picoides pubescens or P. villosus) on an American beech log
Near our first road crossing along the trail, we came upon this stagnant stone-walled spring pool.  Fans of the CBS television show Cold Case set in Philadelphia might remember an episode in which a victim was found drowned in a woodland pond.  The scene was filmed at this spot.

Before it was dammed in 27 places during European colonial times to generate water power for milling, our creek historically hosted an anadromous run of shad; the dams quickly put an end to that, since the first dam, built just two miles upstream of the creek's mouth, blocked the creek (and the shad run) in 1697.  Today, only two dams remain in place, the others having been breached by floods or removed intentionally so that shad runs could be restored.  This dam, a very popular recreational and aesthetic feature known locally as "The Falls," is failing of its own accord - the creek is quickly eroding around the east side of the dam.

Significant erosion around the east side of The Falls dam
Throughout the park, there are beautiful native stone bridges and walls. As in so many urban parks in the United States, the city just doesn't have the money to take care of these cultural, historic and aesthetic amenities, and they are disappearing through neglect and vandalism.  This is the rampart wall of a bridge over a tributary called Paul's Run.

View downstream from the Paul's Run bridge
A streamside sycamore with an unusual growth habit
"The Scream" au natural
"The Yelp"
White Wood Aster (Aster divaricatus)
Rock art on a creekside boulder
Mile-a minute weed (Persicaria perfoliata) growing alongside the creek and perforated by imported biocontrol weevils (Rhinocominus latipes).  This annual vine is an invasive alien scourge in the Mid-Atlantic states.
One of my favorite reaches of the creek
A sandy run below the rocky riffle
Just downstream of this point, we crossed a bridge and returned upstream.  Stay tuned...


Carolyn H said...

What lovely photos. I haven't yet seen mile-a-minute plant here on Roundtop--I hope it stays that way. The ruined bridges are almost exotic looking. Did the shad every return to the stream?

Scott said...

Carolyn: Mile-a-minute weed was introduced into a York County nursery in a shipment of holly seeds from Japan in 1938. It has spread forth ever since. You're lucky that it hasn't appeared at Roundtop, and I hope that it doesn't. I've walked in several natural areas in Lancaster County and the woods were full of the plant.

In addition to sponsoring the dam removals, the Pennsylvania Fish and Boat Commission has been releasing thousands of Hickory Shad fry into the creek each year over the last several years hoping that the young will "imprint" on the creek as their natal water. As far as I know, there haven't been reports of the fish returning from the ocean, but it may be too soon to expect a return since I believe they spend several years in the ocean before they spawn.

Jain said...

What a pretty walk!

Good eye with "The Scream."

I didn't recognize mile-a-minute weed when I scrolled to the picture. For this I am grateful.

Scott said...

Jain: If you see one mile-a-minute weed, trust me, it's just the vanguard. There are plenty more just around the bend. I pulled out the first few sprigs I saw; now, I've overwhelmed with it.