Fungus Among Us

This fungus appeared yesterday on the side of Forbidden Drive south of Bell's Mills. A search online matches this with a Laetiporus sulphureus mushroom otherwise know as "Chicken of the Woods."

This appeared in the May 7, 2009 edition of the Chestnut Hill Local.

In Search of the Source of the Wissahickon Creek Part II

The Montgomery County Planning Commission prepared the underlying map of the Wissahickon Creek Watershed. The intersection of the two red lines is at the Germantown Avenue Bridge. To find the source of the creek, the two red lines indicate the two most distant points from the bridge. Of the two lines, the one to Montgomeryville is clearly the longest, indicating that this must be the area where the source can be found. As seen previously, the alternative definition of the source states that "the furthest point from which water could possibly flow into the ocean," suggests that it is found on the watershed boundary. The map does not provide sufficient information as to the precise location source.

High Water!

In Search of the Source of the Wissahickon Creek

One of the most enduring legacies of the Presidency of Bill Clinton is his policy to make available GPS, the Global Positioning System, for civilian use. Early explorers may have trekked to the far corners of the world, but knowing their exact location is another matter. Recently, it was found that the Four Corners Monument marking the intersection of the boundaries of Arizona, Utah. Colorado, and New Mexico was 1807.14 ft. from the correct location, as found by GPS.

With the advent of GPS, many geographical mysteries can finally be solved. The National Geographic Society set out to determine the precise source of the Amazon River, which they found to be on Mt. Nevado Mismi in the Andes. The photograph is by Jialiang Gao.

It has only been in the last two decades that the source of the Mekong Rivers has been determined. The stream flows from the Lasagongma Glacier on the Tibetan Plateau in Qinghai, China.

While finding the source of the Wissahickon Creek may not require an expedition, the precise location of the creek bed is not always obvious as it can only be glimpsed intermittently. Also the problem arises as to what is creek and what is tributary. It is not so much the daunting distances of a mighty river, but the vagueness of the location of the creek. Geographer Andrew Johnston of the Smithsonian Institution offers (in National Geographic News): A source is defined as the most distant point (from the river mouth) in the drainage basin from which water runs year-around, or alternatively, the furthest point from which water could possibly flow into the ocean.

Looking for Ghosts, Found Trolls

A sample of Wissahickon schist was given out at the opening of the Wissahickon Avenue Bridge. At the dedication ceremony, Carol Jean Vale, SSJ, President of Chestnut Hill College, poked fun at the length of time it took realize the new bridge. She said that it took longer to build it than it took to build the Gold Gate Bridge and the Sears Tower. Among other feats of construction, only the Brooklyn Bridge took longer at 13 years. Half of the 19th century bridge fell into the creek at the beginning of the Clinton Administration. That bridge had been built on eight stone piers of colonial origin. Temporary repairs sustained the bridge for a few years, but when cracks appeared in two of the piers in 1997, it was deemed necessary to replace the it. A furious debate ensued about retaining the historical stonework, which took 5 years to resolve. After a further 330 days of construction, the bridge finally opened on October 26, 2003.

The remnants of the colonial piers can be seen in the banks the the creek under the span of the bridge that allows for overflow in times of flooding. Preserved for the aficionados of historical masonry, it is however unmarked. Also uncredited are the countless hours of detouring that their preservation cost local residents.

The ones who have ventured down to the waterside, apparently did not do so to appreciate our history, or to contemplate the ghost of Marquis de la Fayette crossing the bridge to his encampment at the top of a hill that was to later take his name. Something about the nether regions of bridges draws folk who like to huddle together. Who knew that the Germantown Avenue Bridge has trolls?

Curved Bridge

The view of the new Germantown Avenue Bridge from Goggle Earth shows the realignment of the roadway. Longtime residents of the area will remember the straight 19th century bridge. The approach from the Chestnut Hill side combined a steep incline with a sharp right turn, which proved to be lethal in rainy weather.

With the addition of good lane markings and rumble strips, the designers of the bridge did an excellent job ameliorating a dangerous condition.

Curved bridges are not numerous. A few were designed by the great Swiss civil engineer Robert Maillart. Maillart conceived the entire structure of his bridge as curving. The Germantown Avenue Bridge is a composite of a curved roadway supported by straight beams—a reasonable concession to practicality.

Germantown Avenue Bridge over Wissahickon Creek

To the right of the pier, a pedestrian walkway

splits off as the roadway turns toward the left

The Germantown Avenue Bridge marks the boundary between the flat watershed area and the gorge. At this point, at an elevation of 34 meters above sea level, the creek tumbles down to an elevation of 6 meters at the confluence of the Schuylkill River. While not falling a great height, the descent nevertheless offers the possibility of waterfalls in combination with leisurely flowing stretches.

View Downstream from Base of Bridge

Most visitors to Fairmount Park are familiar with the section of Wissahickon Creek downstream from this point, as it run parallel to Forbidden Drive.

View Upstream from Base of Bridge

The upstream section of the creek is more mysterious as it meanders its way northward, where it is glimpsed from the road side or when it is crossed over by innumerable small bridges that are hardly noteworthy. Where exactly is the source of Wissahickon Creek?