Manatawny Creek Dam Study Area
Watershed
The Manatawny Creek, located in southeastern Pennsylvania, has a drainage area of 91.6 square miles (238.3 square kilometers), and is a tributary to the Schuylkill River and Delaware Bay. The headwaters are located in the New England Physiographic province near Oley, PA while the lower reaches (dam location) are located in the Piedmont Physiographic province near Pottstown, PA. Pottstown, with an estimated population of 21,614 (1996) is the major urban center in the watershed. The major uses of land are forest and open (56%), agriculture (41%), and urban development (3%).
Study Sites
Current studies have selected several sites upstream and downstream of the dam. The reference site upstream is at Glasgow Bridge (MG) while there are three sites in the impoundment region: one above the island (MI), one near the baseball fields (MB) and one at the dam (MD). Two sites are downstream of the dam; the first is just downstream of the dam (MR) and the final site is further downstream near the local college(MC). In addition, there are sites at the confluence of the Schuylkill River (SC) and upstream and downstream of the confluence in the Schuylkill River (SU, SD1, SD2).
Manatawny Creek Dam
A low-head or run of the river dam (a small dam that allows continuous water movement over the top), was built on the Manatawny mainstem around 1850. It is located about 500 meters upstream of the confluence with the Schuylkill River. The dam is approximately 2.5 meters in height, 2 meters thick, and 30 meters across, and is constructed of stone and concrete. Water is impounded upstream of the dam for approximately 800 meters. No fish ladders or other structures were ever constructed to allow resident or migratory fishes to swim upstream of the dam. The land along both banks of the Manatawny from the Schuylkill River to the upper reaches of the impoundment area are owned by the city of Pottstown, and are managed as open space and public parks. As of July 1999, Pennsylvania DEP designated the dam an "orphan" with no legal owner.