John Heinz National Wildlife Refuge

Site Description

  • State: Pennsylvania
  • County: Philadelphia
  • Ownership: Federal


  • Tract 5 Impoundment: 145 acres

Ecology and Management

A hawk perches at John Heinz National Wildlife Refuge. Photo credit: Derik Pinsonneault, USFWS.

The John Heinz National Wildlife Refuge at Tinicum is located just minutes from downtown Philadelphia and is known for its rare tidal freshwater ecosystem and wild rice stands. The freshwater impoundment is a centerpiece of the refuge and attracts a large diversity and abundance of waterbirds. Located along the Atlantic Flyway, the refuge is considered an Important Bird Area by National Audubon (Cohen and Johnson 2004). Refuge staff have involved the impoundment in a number of bird monitoring schemes over the years including a regional USFWS study of impoundment management (Green et al. 2007), the International Shorebird Survey (ISS), and the International Waterbird Management and Monitoring (IWMM) program. The refuge (and the impoundment in particular) is a major birding destination – over 6,700 eBird checklists have been recorded from the Heinz impoundment hotspot tallying a total of 290 species. High counts of shorebirds (3,000 Semipalmated and 2,500 Least Sandpiper) and waterfowl (1,000 Northern Shoveler, Northern Pintail, and Green-winged Teal) are notable. The Red-bellied Turtle (Pseudemys rubriventris), a state-threatened species in Pennsylvania, is found in the impoundment.

The impoundment, which dates back to flood control efforts in the 18th century, was acquired by the USFWS from the City of Philadelphia in 1972. It is currently managed by refuge staff to support a variety of waterbirds. The primary management action is drawing down water levels to expose mudflats for migratory shorebirds during the late summer periods. Water levels are raised again in fall for migrating and wintering waterfowl (Green et al. 2007, Stoltz 2012).


The embankment surrounding the impoundment is relatively low (~3-6 feet above mean high water) and was breached during several major storm events (e.g., Hurricane Floyd in 1999, and at least two others). Significant erosion has happened in recent years during high rainfall events: Hurricane Irene and Tropical Storm Lee in 2011. Hurricane Sandy in 2012 caused minor overtopping and erosion. The damage was repaired following each event. The main vulnerability for the Heinz impoundment is not necessarily storm surge from tidal waters as it is with many other coastal impoundments. Heavy rains can cause waters in adjacent Darby Creek to rise and enter the impoundment on the northern end of the impoundment,which then causes damage to the southern embankment as the water seeks an exit. The refuge is considering restoration measures which would allow freshwater tidal flows to more freely enter and exit the impoundment. Sea level rise is a threat to the freshwater marsh ecosystem at the site as the saltwater transition line occurs about two and a half miles downstream.

Human Value

Heinz is known as America’s First Urban National Wildlife Refuge and receives over 100,000 visitors per year, nearly three-quarters of which are local residents (Stolz 2012). The majority of these visitors are visiting the trails surrounding the impoundment for non-consumptive purposes such as hiking, photography, and wildlife observation. Staff provide programming and weekend walks to up to 13,000 people annually, and up to 8,000 school children visit on class trips. The refuge hosts its own summer camp and is visited by an additional 50-60 outside summer camps during an average year.


We are grateful to Lamar Gore and Brendalee Phillips (Heinz NWR) for providing much of the information contained on this page.

Literature Resources

Below is a list of scholarly articles describing research occurring at or near the impoundment:
  • Bell, B., J. R. Spotila, and J. Congdon. 2006. High incidence of deformity in aquatic turtles in the John Heinz National Wildlife Refuge. Environmental Pollution 142:457-465.
  • Cohen, M., and J. Johnson. Pennsylvania Important Bird Area #73: John Heinz National Wildlife Refuge at Tinicum Phase 1 Report. New York, New York: National Audubon; 2004.
  • Gorton, G. Tinicum’s Most Famous Bird, 35 Years Later. Philadelphia: Delaware Valley Ornithological Club; 2015.
  • Green, A., J. Lyons, M. Runge, W. Kendall, H. Laskowski, S. Lor, and S. Guiteras. Timing of impoundment drawdowns and impact on waterbird, invertebrate, and vegetation communities within managed wetlands, Study manual – Final version field season 2007. Laurel, Maryland: USGS Patuxent Wildlife Research Center; 2007.
  • Green, A. W., W. L. Kendall, H. P. Laskowski, J. E. Lyons, L. Socheata, and M. C. Runge. Draft version of the USFWS R3/R5 Regional Impoundment Study. Washington, D. C.: U. S. Fish and Wildlife Service; 2008.
  • Harding, J. J. 1980. Birding the Delaware Valley Region: A Comprehensive Guide to Birdwatching in Southeastern Pennsylvania, Central and Southern New Jersey, and Northcentral Delaware. Temple University Press, Philadelphia, Pennsylvania.
  • Miller, J. C. 2001. Update of the Status of Birds in the John Heinz National Wildlife Refuge at Tinicium and Adjacent Areas in Philadelphia and Delaware Counties, Pennsylvania 1995-2001. Cassinia 69:27-31.
  • Stolz, G., et al., John Heinz National Wildlife Refuge at Tinicum, Comprehensive Conservation Plan. Washington, D. C.: U. S. Fish and Wildlife Service; 2012.