- Mouth Tidal Wetlands Delaware County, PA Natural Heritage Inventory Ü

Legend Core Habitat (focus NHI site) Core Habitat (other NHI sites) Interior Forest Supporting Landscape Forested habitat 100 meter Riparian Buffer OpenSpace & Recreation 0 0.25 0.5 1 100 foot Riparian buffer Public Park Kilometers Township Boundary Homeowner's Association 0 0.25 0.5 1 Miles County Boundary Privately Eased Land

Ridley Creek - Crum Creek Mouth Tidal Wetlands – High significance

PNDI Rank2 Legal Status2 Last Species of Concern: Taxa1 Global State State (Proposed) Seen Quality2 Osprey (Pandion haliaetus) B G5 S2B PT (PT) 2008 E Peregrine Falcon (Peregrine Falcon) B G4 S1B,S1N PE (PE) 2009 E Indian wild rice (Zizania aquatica) P G5 S3 PR (PR) 2009 D

1 A = Amphibian; B = Bird; C = Community; F = Fish; L = Lepidopteran; O = Odonate; P = Plant; M = Mammal; R= Reptile, U = Unionoid (Mussel) 2 Please refer to Appendix III for an explanation of PNHP ranks and legal status 3 This species is not named by request of the jurisdictional agency overseeing its protection

Location: The shoreline and floodplain includes the tidal marsh remnants between the southern part of the mouth of Darby Creek downstream to the northern part of the mouth of . Between these two points are the mouths of both Ridley Creek and Crum Creek. o Municipalities: o Chester City o Eddystone Borough o Ridley Township o USGS Quadrangles: o Bridgeport Quadrangle o Watersheds: o Crum Creek o Darby Creek o Delaware River o Ridley Creek o 1992 Delaware County Natural Areas Inventory reference: o None o 1998 Delaware County Natural Areas Inventory Update reference: o None

Description: This highly industrialized portion of the Delaware River shoreline supports remnant freshwater tidal marsh and mudflat habitats in a much degraded context. In some areas, the crumbling, paved footprints of past industrial activity are giving way to expanses of early successional vegetation. Vegetation has begun to colonize the unused piers and unpaved portions of the former industrial sites. Where the shoreline vegetation strip widens, it supports trees, shrubs, vines and herbaceous vegetation between the rubble- armored hardened shoreline and the crumbling pavement of the former industrial sites. Along the periphery of the river, native species of plants and animals compete with introduced species for the limited space and resources available for their use.

The abandoned wooden pilings, piers and ramps within the river help to diminish the impact of wave action from passing ships on the river shoreline and may help to encourage the formation of tidal mudflats along this portion of the river. Many of the formerly active piers have been neglected for long enough that trees, shrubs and herbaceous vegetation have colonized them. Between the vacant piers are areas of shallow water and deep mud that, in some cases already support tidal mudflat vegetation. These small estuaries help support young fish populations, an essential ecological function of shallow water habitats along the river.

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Species of Concern Considerations: o Being primarily fish eaters, Ospreys utilize aquatic habitats for food gathering and upland habitats or prominent features as nesting areas. Osprey will nest on artificial structures including poles and towers that support electric or phone lines, cell-phone relay towers, buildings, fences, and channel markers. Osprey populations tend to be clustered where shallow waters and nesting support structures are available. The aquatic habitats provided by the river and tributaries as well as nesting structures are both important components of this species’ habitat preferences. Since Osprey forage for fish visually, they are sensitive to poor water quality including loss of clarity. A decrease in water quality or clarity can have a direct negative effect on Osprey foraging efficiency and perhaps nesting success. o Successfully breeding pairs of Peregrine Falcons have been documented at this site over the past several years. Peregrine Falcons require a combination of large open areas for hunting and tall, inaccessible ledges for nesting. Ledges can either be natural cliffs or human-made structures that have similar structural characteristics. Though buildings and bridges are not the traditional habitat for this species, pairs are nesting successfully in these situations around the country. Peregrines range widely to forage for prey, frequently several kilometers. There is high potential for collisions with structures and automobiles in this hunting territory. o Indian wild rice is an annual plant that typically grows in tidally influenced shoreline marshes. This plant is adapted to the twice daily flooding disturbance and shallow water conditions that occur in wide floodplain habitats along the Delaware River and do well in habitats otherwise favoring ‘weedy’ species of plants. Populations of this species can be enhanced by maintaining the natural fluctuations in the river’s water level and restoring the natural conditions of its shoreline.

Forest Cover / Natural Communities: The river shoreline at this location is highly industrialized and only a narrow band of remnant vegetation occurs along its banks. A few areas within the tidal zone have emergent aquatic vegetation typical of the habitat.

Ownership: o This portion of the Delaware River shoreline currently has no publicly owned land but rather is held in several relatively large privately-owned parcels. The large parcel size can be tremendously helpful towards implementation of consistent conservation actions across this significant piece of the landscape. Conservation action should proceed before ownership fragmentation makes this process more difficult.

Habitat Disturbances: o Historic: o Most of the area between the I-95 freeway and the Delaware River has been greatly modified from the extensive system of tidal marshes that used to dominate the shoreline. The tidally influenced shoreline of the Delaware River historically hosted expansive freshwater tidal marshes, especially at the mouths of the tributary creeks. Over the past several centuries and especially this past one, the marshes have been diked, ditched, drained, filled and converted to dry areas of commerce and residence. As late as 1900 there were extensive marshes at the mouth of Crum Creek where a lighthouse was accessed by way of a 2000 foot long wooden walkway through the marsh (Harshberger 1904). Most of this area is still within the floodplain of the river and is likely to be subject to future flooding from increasingly unpredictable weather patterns and an anticipated rise in sea level. o Formerly, this area was a very active shipping and industrial part of North America. While still an important entryway for sea freight, much of the riverfront has seen considerable change in the past few decades. Many areas that had been associated with shipping and industry have been demolished, leaving various large and small patches of vacant ground and their associated piers along the riverfront. o Rail lines and roadways were built parallel to and though the former marshes. o Industrial plants and a coal-fired electric generating plant were built on the banks of the river. One industrial plant was built directly on top of Crum Creek, disconnecting upstream and downstream portions of the creek. Delaware County Natural Heritage Inventory 2011 - Ridley Creek, Crum Creek Mouth Tidal Wetlands / 258

o Current: o Much of the area remains as it was at the time of the 1937 aerial photos, with a mix of industrial areas and dilapidated former shipping wharfs. o In 2004 the oil tanker Athos I hit an abandoned and uncharted anchor, ruptured its hull, and spilled 30,000 gallons of oil into the Delaware River o The impact of wave action from passing boat traffic is significant and acts to constantly scour the southern side of the island, which is exposed to the shipping lane. The large wakes of the ocean-going freighters that use the Delaware River channel are often in excess of six-feet tall and have caused significant erosion on the up, and downstream ends of the island, shortening it by over 800 feet since the 1971 aerial photo was taken. o Rapid development has occurred outside of and on the periphery of the core habitat area, fragmenting the landscape with additional buildings, roads and infrastructure and increasing the amount of impervious surface and edge habitat in the immediate watershed. o Stormwater runoff from the highly developed surrounding communities flows into the watershed system with little opportunity to be slowed or filtered. This results in increased downstream flooding and erosion and is a potentially significant non-point source of pollution. Runoff from these sources has significantly higher levels of sediment, nutrients, pesticides, herbicides and other pollutants than runoff filtered through natural vegetation. o Exotic Species – This disturbed strip of vegetation is frequently dominated by invasive non- native trees such as tree-of-heaven, princess tree, Norway maple, Siberian elm, white poplar and white mulberry. Invasive shrubs and vines frequently dominate the understory including Japanese honeysuckle, porcelain berry, Asiatic bittersweet, multiflora rose, bush honeysuckles, common privet, barberry, paper mulberry and autumn olive to name a few.

Conservation Actions: o Future long range goals for this section of the river should be to simultaneously enhance the native ecology of the riverfront as well as provide public access and park space opportunities. Since much of the Delaware River shoreline in Delaware County is currently transitioning from past industrial and shipping activity, the county is presented with an excellent opportunity to recreate a continuous greenway corridor along this stretch of the river. This linear area currently lends itself well to the reestablishment of a ribbon of native vegetation that will help provide habitat for native plants and animals while filtering and trapping runoff from the urban and suburban areas before it enters the river. In addition, the linear corridor can function as a portion of a public greenway along the length of the Delaware riverfront. Such a public amenity would greatly improve the quality of life for all residents and visitors to the area. o Future developments should be set back from the river shoreline to accommodate a 100-meter wide vegetated riparian buffer between the river’s edge and development activity. o The shoreline habitat can be improved by removing portions of the armored bulkheads and reconnecting the river to a portion of its natural floodplain. o Restore and protect the natural hydrology of the river and it tributaries. This may require that road crossings involve bridge systems that would preserve the wide sluggish waters associated with marshes and slow flowing waterways. o Replant the riparian area in native trees and shrubs to enhance its ecological value. o Reduce the impact of the wakes from passing ships and small boats. This may entail establishing a shoal that can absorb the wake impact, and/or reducing the speed at which boats may travel through the river. o Conserve and expand the forested riparian buffers of Ridley Creek, Crum Creek and their tributaries. Establish at least a 100 foot buffer of woody vegetation along the creeks to help reduce erosion, sedimentation, and pollution. Additionally, best management practices (BMPs) that focus on limiting the introduction of non-point sources of pollution into surface and groundwater should be applied to the upstream watershed.

References cited: Harshberger, J. W. 1904. A phyto-geographic sketch of extreme southeastern . Bulletin of the Torrey Botanical Club 31: 125-159. Delaware County Natural Heritage Inventory 2011 - Ridley Creek, Crum Creek Mouth Tidal Wetlands / 259