All and every person or persons desirous of improving their water lots, within the district of Southwark, be and they are hereby authorized and empowered, after submitting their plan or plans of improvement to the board of wardens of the port of Philadelphia, which being by them approved, but not otherwise, to extend their piers, with or without thoroughfares, to the distance of one hundred and twenty-five feet from the east side of Wharf street, as regulated by the act to which this is a supplement, into the river Delaware.
53 P.S. § 16869