 
		 
		 
		Drainage area plan, early 19th century
 
		Plans and maps of the Pennypack Creek Watershed in Philadelphia
 
		Wingohocking Sewer across Penn St.
 
		History of Belfield (1934)
 
		Frankford Creek Watershed: A historical overview of the Philadelphia section
 
		Frankford Creek Watershed Historical Timeline
 
		Down Under III: A walk in the Dobson’s Run Storm Relief Sewer, June 15, 2010
 
		Drawing Dock Creek
 
		Down Under, Part 2: Beaver Creek as it appears today
 
		Overbrook, as it was. A brief history of the Overbrook neighborhood of Philadelphia, focusing on changes in the natural landscape.
