53 Pa. Stat. § 16846
That no district, borough, or township, bordering on either the river Delaware or Schuylkill, within the bounds of the city or county of Philadelphia, shall be entitled to or receive a license to erect or extend a wharf or wharves into the tide-way of either such streams, without having filed in the office of the board of wardens for the port of Philadelphia a full and correct plan of the river front bordering on such district, which draft or plan shall embrace the soundings or points not more than seven hundred feet distant from each other, along the water front, at intervals of not more than fifty feet from low-water mark, and extending to the channel of the river, which draft or plan shall be attested by the surveyor of such district, borough, or township, and remain on record in said warden's office, and free for the inspection of all parties interested.
53 P.S. § 16846