CHAPTER 8 Middle Perkiomen Creek Corridor

The Middle Perkiomen Creek Corridor is focused on the riparian corridor along the Perkiomen Creek and the lower reach of the East Branch Perkiomen Creek. It provides a setting for the Perkiomen Trail and contains habitat for riparian species. The corridor is a critical link in the county trail network as it provides the connection between the Schuylkill River and Perkiomen Creek trails.

Description Location The corridor extends for approximately seven miles along the Perkiomen Creek from the south end of Schwenksville to the mouth of Skippack Creek just below Arcola. It takes in a total of 1,750 acres, including portions of Salford, Skippack, Perkiomen, Lower Providence, and Up- per Providence Townships and Collegeville Borough. The corridor links the Spring Mountain Conservation Landscape with the Skippack Creek and the Middle Schuylkill River Landscapes (Figure 8.1).

Hydrology The corridor is entirely within the watershed of the Perkiomen Creek and includes the lower por- tions of several tributaries including the East Branch Perkiomen Creek. Floodplain wetlands are included as are 3 large islands located at Rhans, Yerkes, and Arcola. This stretch of the Perkiomen Creek is classifi ed as WWF MF (warm water fi shery, migra- tory fi shes).

Geology From Schwenksville to Yerkes, the cor- ridor is underlain by Brunswick Forma- tion shales and siltstones with a few narrow bands of Lockatong Formation argillites. Below Yerkes the Lockatong Formation dominates the landscape, and creates the steep slopes that defi ne the Perkiomen Creek between Schwenksville and Collegeville creek valley (Figure 8.2). In 1993 dinosaur footprints were discovered in exposed strata of a band of Lockatong that cross- es the Graterford Prison site that is adjacent to the corridor. Some specimens were subsequently removed from the site for study and conservation at the William Penn Museum in Harrisburg. Because of its location on the grounds of the prison, the site has remained undeveloped.

Natural Areas Inventory Update 2007 141 Forest Cover The corridor includes 758.5 acres of forest (43 percent of the land surface). Two hundred and nineteen (219) acres qualify as interior forest habitat. A riparian forest buffer covers 66.9 acres of the Central Perkiomen Corridor (Figure 8.3). Critical Features No endangered, threatened or rare species of plants or animal are currently known to exist in the Middle Perkiomen Creek corridor. An earlier record of slender blue iris was not found in 2006 despite a search of the area. The site, referred to as “Perkiomen Floodplain/Rahns” in the 1995 Natural Areas Inventory, has undergone successional growth that probably eliminated habitat for the slender blue iris that once grew there. Of geological interest is an unusually large collec- tion of dinosaur footprints at the Graterford Prison site (see further discussion under “Areas Still Need- ing Protection” below.) The 1995 Natural Areas Inventory listed “Colleg- eville Floodplain” and “Otts Road Floodplain” as sites of local signifi cance. These sites are included in the discussion of Central Perkiomen Valley Park below. Reptiles and Amphibians – Ten species of reptiles and amphibians were documented in the Middle Perkiomen Creek Corridor by Marlin Corn as part of this study (Table 8.1). All are common species. Common snapping turtle, photo by Marlin Corn

Table 8.1 — Reptiles and Amphibians of the Middle Perkiomen Corridor

Salamanders Northern two-lined salamander Frogs and Toads Gray treefrog Spring peeper Green frog American toad Turtles Eastern painted turtle Snapping turtle Box turtle Common musk turtle Snakes Northern water snake

142 Natural Areas Inventory Update 2007 Natural Areas Inventory Update 2007 143 144 Natural Areas Inventory Update 2007 Natural Areas Inventory Update 2007 145 146 Natural Areas Inventory Update 2007 Birds – Breeding Bird Atlas data for 2004-2008 lists a total of 62 species for block 81C75 that includes a section of the Middle Perkiomen Creek Corridor near Collegeville (Table 8.2). The list includes several riparian species such as Louisiana Waterthrush, Northern Parula, and Warbling Vireo. In addi- tion, riverine species including Osprey, Canada Goose, Mallard, Green Heron, Great Blue Heron, Double Crested Cor- morant, and Common Merganser are Pair of Common Mergansers, photo by Howard Eskin found in the corridor.

Table 8.2 — Birds of the Middle Perkiomen Creek Corridor (from 2004-2008 Breeding Bird Atlas data for Block 81C75.)

Confi rmed Probable Eastern Kingbird Canada goose Green Heron Red-eyed Vireo Mallard Ruby-throated Hummingbird Northern Rough-winged Swallow Wild Turkey Downy Woodpecker Barn Swallow Osprey Carolina Wren White-breasted Nuthatch Red-tailed Hawk European Starling Blue-gray Gnatcatcher Great Horned Owl Yellow Warbler Veery Red-belied Woodpecker Song Sparrow Wood Thrush Northern Flicker Indigo Bunting Gray Catbird Eastern Phoebe Red-winged Blackbird Northern Mockingbird Yellow-throated Vireo Baltimore Oriole Ovenbird Warbling Vireo Northern Parula American Crow Possible Common Yellowthroat Tree Swallow Wood Duck Scarlet Tanager Carolina Chickadee Great Blue Heron Eastern Towhee Tufted Titmouse Cooper’s Hawk Field Sparrow House Wren American Kestrel Rose-breasted Grosbeak American Robin Mourning Dove Brown-headed Cowbird Louisiana Waterthrush Turkey Vulture House Finch Northern Cardinal Chimney Swift Orchard Oriole Eastern Wood-peewee Observed Common Grackle Acadian Flycatcher Double-crested Cormorant Great Crested Flycatcher Common Merganser

Natural Areas Inventory Update 2007 147 Past Uses The Perkiomen Creek corridor was the site of the Perkiomen Railroad, which was completed be- tween 1868 and 1874. The railroad stimulated the founding of numerous towns along its length and opened central Montgomery County to development. Today the abandoned railroad bed is the route of the Perkiomen Trail.

Preservation Status and Other Designations The Pennypacker Mills Property, a 142-acre site owned by the county which surrounds the headquarters of the Perkiomen Watershed Conservancy, anchors the corridor at the northern end. Montgomery County also owns 506 acres of fl oodplain land, not all contiguous, which collec- tively makes up Central Perkiomen Valley Park (Figure 8.4). Trailheads are provided at several locations, but some areas are completely undeveloped.

Core Areas Pennypacker Mills The Pennypacker Mills historical site is located at the confl uence of the East Branch and the main stem of the Perkiomen Creek and includes portions of the stream banks of both. Dramat- ic cliffs along the East Branch Perkio- men Creek support populations of native columbine, rockcap fern, maid- enhair spleenwort, and other plants; in addition we observed cliff swallows nesting in the rock crevices. Floodplain forests are present along the Perkiomen and East Branch. The 142-acre site also includes the historic Pennypacker Mansion and sur- rounding grounds. A wet meadow with a high diversity of sedges and forbs was mentioned as a site of local signifi cance Students exploring aquatic life in the East Branch Perkiomen Creek at in the 1995 Natural Areas Inventory. Pennypacker Mills Plant species include lousewort, yellow- eyed grass, blue-eyed grass, golden ragwort, fringed loosestrife, golden-alexander, bluets, sensi- tive fern, soft rush, woodrush, bittercress, Robbin’s-plantain, and numerous sedges. The Perkiomen Creek Conservancy has its headquarters across Haldeman Road from Penny- packer Mills, and operates an active environmental education program that brings school classes to the site for hands-on lessons in aquatic and terrestrial environments.

Central Perkiomen Valley Park Central Perkiomen Valley Park consists of over 500 acres of linear parkland along both sides of the Perkiomen Creek. Although there are a few gaps, the park includes a major portion of the

148 Natural Areas Inventory Update 2007 trail corridor. Some sites are completely undeveloped, but trail and river access points, picnic groves, walking paths, and ath- letic fi elds are provided at several locations. An historic mill overlooks the creek at Plank Road. Most of Central Perkiomen Valley Park is in the fl oodplain and covered with silver maple – box-elder fl oodplain forest. As- sociated canopy species include sycamore, river birch, hack- berry, bitternut hickory, white ash, American elm, basswood, and black walnut. Spicebush and silky dogwood are common native shrubs; several non-native invasive species such as mul- tifl ora rose and obtuse-leaved privet are also frequently present. Poison-ivy and wild grape are common woody vines. The herbaceous layer on fl oodplains throughout the county is dominated in early spring by extensive stands of Virginia blue- bells. In recent years, the yellow fl owers of lesser celandine, a A big hackberry tree on the Perkiomen non-native invasive perennial that spreads by small tubers have Creek fl oodplain also become a common sight. Other native fl oodplain wild- fl owers include trout lily, spring-beauty, common blue violet, white avens, and Virginia water- leaf. Sedges including Carex crinita and Carex grayi are frequent. Later in the season rice cut- grass, monkey-fl ower, jewelweed, ditch stonecrop, false nettle, cut-leaf conefl ower, thin-leaved sunfl ower, sneezeweed, cardinal fl ower, and great blue lobelia are common. Non-native herba- ceous species include dame’s-rocket, moneywort, fi eld garlic, stinging nettle, purple loosestrife, Japanese knotweed, and Japanese stiltgrass. Wet meadows dominated by reed canary grass, halberd-leaf tearthumb, water smartweed, and common cat- tail and yellow water-lily are found in back channels or other areas of shallow standing water. Scoured gravel bars are present along the Perkiomen where we have found Perkiomen Creek below Collegeville numerous shells of eastern elliptio, a native freshwater mussel as well as those of the non-native Asian clam. Barred owls were also observed in the fl oodplain forest.

Additional Sites Requiring Protection Graterford Prison Graterford Prison occupies 1,780 acres adjacent to the Perkiomen Creek corridor. Containing farm fi elds, several tributary streams, and wooded slopes, the prison is one of the largest un-

Natural Areas Inventory Update 2007 149 developed tracts of land in the county. In February 2007, the state announced that they were con- sidering relocating the prison. If that were to happen, future use of the site would be in question since current zoning allows only for correctional facilities, farming, or open space. Graterford Prison contains an important geological feature. In 1993 an inmate accidentally discovered dinosaur footprints on an outcrop of Lockatong Formation rocks along a tributary of the Perkiomen Creek. Geologists from the Pennsylvania State Museum and the Bureau of Topographic and Geologic Survey subsequently confi rmed the presence of hundreds of fossil- ized footprints of at least 4 dinosaur species. It is one of Pennsylvania’s most extensive late Triassic tracksites. Specimens were removed from the site and placed in the William Penn Museum in Harrisburg for conservation and study. More remain in place; however, severe erosion of the ravines where the dinosaur footprints were originally found may be a threat to the integrity of the re- source. The erosion is caused in part by extremely heavy browsing of the surrounding forested slopes by deer. The Perkiomen Creek fl oodplain as well as the forested ravines that include the dinosaur foot- prints should be preserved as open space if the prison is relocated. In addition, deer density on the site should be drastically reduced to allow forested slopes to revegetate.

Recommendations Land Preservation and Connectivity • Preserve all unprotected lands bordering the Perkiomen Creek; a particular area of concern includes forested slopes along the east side of the Perkiomen Creek between Collegeville and the mouth of the Skippack Creek. • Seek protection of Perkiomen Creek fl oodplain and valleys of tributary streams on the Graterford Prison property. Land Management • Reduce deer density throughout, including on the Graterford Prison site. Interpretation and Education • Increase opportunities for environmental education focused on stream ecology.

Bibliography Lucas, Spencer G. 2006. Tetrapod footprint assemblage from the Upper Triassic Passaic Forma- tion, Montgomery County, Pennsylvania. Geological Society of America Abstracts with Pro- grams 38(2): 65. Sullivan, Robert M., Kesler Randall, and Michael Hendricks, and William E. Kochanov. 1994. The Graterford dinosaurs: tracking Triassic travelers. Pennsylvania Geology 25(4): 2-9. Mastrull, Diane. 2007. Worse than jail? Sprawl. Philadelphia Inquirer Feb. 7, 2007. Pennsylvania Breeding Bird Atlas http://bird.atlasing.org/Atlas/PA/Main, accessed 5/7/2007.

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