Intensely Developed Areas (IDAs) (PDF) are in existing high density residential, commercial and industrial developments where little of the natural environment remains, and are to serve as redevelopment areas where development is already concentrated. The water quality benefits of the historical RPA buffer have also been reduced because development has severely altered the natural state of the area. In IDAs, the goal is to reduce the nonpoint source pollution when properties are redeveloped and to explore opportunities to re-establish the 100 feet RPA buffer where possible.