53 Pa. Stat. § 16852
It shall be the duty of the surveyor of the county of Delaware to prepare, within twelve months from the passage of this act, a plan of the Delaware river front of said county, showing the present line of low-water, with the depths of water for seven hundred feet out from said line of low-water, at distances of fifty feet from said line, and at distances not more than five hundred feet apart, and upon the receipt of said plan by the wardens for the port of Philadelphia, they shall define a wharf-line for Delaware county, beyond which it shall not be lawful for them to authorize the construction of any wharf or pier, and if any person shall trespass on the tide-way of the river beyond the line of low-water, as defined by the survey now authorized, without license from the port wardens, he, or they, so offending shall be liable to the penalties, as provided in existing acts for like offenses.
53 P.S. § 16852