The Lower Estuary region stretches south from the Delaware-Pennsylvania border to the point where the Delaware River opens to become the Delaware Bay. This region encompasses 1,020 square miles, and this includes the Christina River Basin in Delaware and the Salem River Watershed in New Jersey, as well as several smaller watersheds. The region is characterized by gently sloping topography in the north, giving way to relatively flat coastal plain to the south, and this includes a patchwork landscape of forests and fields that are punctuated by development throughout, including the densely populated City of Wilmington. Riverfront industry and the Port of Wilmington make this area a significant economic resource, and this presents many of the same opportunities and challenges as in the Upper Estuary region. The mixing of salt and fresh water in this portion of the Delaware River makes turbidity and its effects on legacy pollutants a major concern. And the importance of maintaining wetlands here for water quality and flood control makes sediment budgeting an important issue.