Reserve Basin is a historic, man-made saltwater basin located within the Philadelphia Navy Yard, adjacent to the Delaware River. It is a former naval docking area, now part of a redeveloped urban waterfront. The basin's primary connection to the tidal Delaware River is controlled by tide gates, which are crucial for managing water levels in the adjacent FDR Park; these gates normally prevent saltwater from entering the park's freshwater system during high tide and allow the park to drain during low tide. Paddlers should be aware that the basin is subject to tidal influence from the Delaware River. The basin is surrounded by the infrastructure of the old Navy Yard, offering a unique industrial and historical backdrop for a paddle. Notable sights include views of decommissioned naval vessels, as the basin has historically been used as a mooring for the reserve fleet, including submarines and the aircraft carrier USS John F. Kennedy. Kayaking tours and boat rentals are advertised in the broader Navy Yard area, suggesting commercial access may be available. The water body is urban and industrial in character, with paddling experiences like sunset tours promoted. There is no information regarding specific hazards, water quality, seasonal patterns, or regulations for private paddlers. The basin's size and shape are not quantified, but it is depicted as a substantial enclosed water area within the shipyard.