Urbanization trend of Barnegat Bay Watershed of New Jersey 1986 –€“ 2012

Background/Question/Methods: Barnegat Bay Watershed is an environmentally sensitive area in New Jersey due to its proximity to the Pine Barrens and Barnegat Bay. Urbanization was identified as the main reason for nitrogen and phosphorous pollution of the Barnegat Bay (Wieben and Baker 2014). To evaluate the impact of New Jersey Smart Growth policies (http://www.njfuture.org/smart-growth-101/primer/), land use changes of the past three decades are quantified and urbanization trends are examined based on the digital land use and land cover data from New Jersey Department of Environmental Protection (http://www.nj.gov/dep/gis/listall.html) using Geographic Information Systems (GIS) and spatial statistics. These data were developed and processed from high resolution orthophotography taken in 1995, 2002, and 2012 with sub-meter spatial resolution.

Results/Conclusions: The results show that urbanization of the watershed had been slowing significantly from an 11,877 acre expansion in 1995 to only 3,080 acres in 2012. About 78% of the 11,877 acre expansion in 1995 was from clear-cut forest. It reduced to 54% of 3,080 acres in 2012, a 7,600 acre reduction.  Less than 8% of the urban expansion in 1995 was from barren land or existing built-up land. It increased to 37% in 2012. All types of newly developed urban land shrunk significantly in the past two decades except for that used for transportation and utilities. The average patch size of urban sprawl decreased from 6.7 acres in 1995 to 1.6 acres in 2012. No significant change was found in the spatial relationships between newly developed urban areas and a major road or an existing urban land. The spatial relationships between the newly developed urban areas and the locations of commercial centers and recreation fields, however, have been changed dramatically or even reversed in some cases. These changes may be attributable to New Jersey’s graduate population decline, smart growth policies, and evolution in information technology. The trend will have significant implication for future ecosystem planning and management of the watershed.