53 Pa. Stat. § 16854
By direction of the board of wardens, the chief engineer and surveyor of the city of Philadelphia shall be required to prepare a map or plan from actual survey to be made within twelve months from the passage of this act of the entire Delaware front of the city of Philadelphia, specifying the depths of water from the fast land to the wharf line as already established; and it shall be the duty of the port wardens, upon the receipt of the said map or plan, to fix and determine an arbitrary line of low-water, beyond which no encroachments or improvements of any kind shall be made without license had and obtained from the board of port wardens, agreeably to the acts of assembly of this commonwealth; and in case any person shall trespass upon the tide-way of the river Delaware, beyond the line of low-water so defined, they shall be subject to a penalty of not less than five hundred dollars, nor exceeding four thousand dollars, with costs of suit, and shall, if the board of wardens so direct, remove any or all obstructions at their own proper cost and expense. The penalty so incurred may be collected as other penalties under the original acts, and the supplements thereto, establishing a board of port wardens are collectible and shall be appropriated to the use of said board of wardens.
53 P.S. § 16854