The Upper Estuary region stretches southwestward from Trenton, New Jersey, to the Pennsylvania-Delaware border, and it consists of 1,743 square miles of small sub-watersheds in Pennsylvania and New Jersey. This region is characterized by a gently sloping topography. This area is defined largely by the main stem of the Delaware River and a diverse landscape of forests and fields that are frequently punctuated by significant development, including the Cities of Philadelphia, Trenton, and Camden. Riverfront industry and development, as well as several major ports, make the Delaware River a critical economic resource to both states in this region, presenting both opportunities and challenges. Contaminants from an industrial legacy and water withdrawals serving the needs of industry and urban populations are the major sources of concern here. Freshwater tidal wetlands are rare throughout the nation but are a signature trait of this region. However, most of these have been lost over the past few hundred years unfortunately.