The force of all that extra water from the ocean backed into the Delaware Bay, adding to the high tide along the Delaware River Thursday night.
ALSO SEE: Dozens rescued during flooding in Margate caused by Hurricane Erin
The river spilled over its banks along Columbus Boulevard at Penn's Landing, near Race Street.
The river rose to moderate flood stage in the city and in Burlington, New Jersey.
Forecasters predict it will hit the same level at 2 a.m. Saturday.
RELATED: Coastal flooding remains concern at Jersey Shore as Hurricane Erin moves away from East Coast
Tracking Hurricane Erin as storm moves away from East Coast