Over centuries, the Raritan River Basin has seen substantial development and landscape change. During that time some streams have been buried in culverts, others simply diverted, with little record of these changes. Within that basin, the most developed portion is the Lower Raritan Watershed with substantial impervious surface coverage (approximately 34%), high population density, and significantly modified stream networks (e.g., stream straightening and burial, culverts, underground retention). Over hundreds of years of anthropogenic influence historic stream channels have been altered or “disappeared,” resulting in increased flooding, compromised water quality, and decreases in aquatic and other species. In addition, many Lower Raritan Watershed municipalities have no way to understand the lost natural and cultural heritage represented by the historic hydrology, the failing underground infrastructure and the collapse of buried streams.
Funded by a mini-grant from the Raritan River Research Consortium and working with the Lower Raritan Watershed Partnership (http://lowerraritanwatershed.org/), the Geohealth Lab at CRSSA undertook this project as a first step towards capturing the Raritan River’s lost heritage by creating new data while making existing records more widely available and used.
As a historic region, the landscapes of the Raritan Basin are captured in a variety of maps. For this project an Environmental Geomatics major, Colin Marx, developed a list of archival map sources and began going through them looking for maps showing streams in or near the study area. For images and maps that showed Raritan tributaries, the digitized imagery was georectified in ArcGIS Pro. The maps were then compared with contemporary USGS NHD Plus stream data to identify places where the two sources diverged.
A Modern Terrain Analysis Approach
With the growing availability of high-resolution terrain data, particularly LiDAR data (Light Detection and Ranging), a modern alternative is to study the shape of the land’s surface for clues to where unmapped water might flow. The landscape above a culvert might still be valley shaped in ways that hint at the landscape’s past. To explore the potential for this tool, a pilot project was undertaken over a small study area.
David L. Tulloch
Associate Professor, Department of Landscape Architecture
Associate Director, Grant F. Walton Center for Remote Sensing and Spatial Analysis (CRSSA)
Grant F. Walton Center for Remote Sensing and Spatial Analysis (CRSSA)
School of Environmental and Biological Sciences
Rutgers, The State University of New Jersey
14 College Farm Road, Cook Campus
New Brunswick, NJ USA 08901-8551
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