Identification and Mapping of Riparian Vegetation in Eastern North Carolina by Remotely Sensed Data

Abstract

The study of riparian buffer zones, the areas surrounding streams, is important in understanding water quality, nutrient cycles, and erosion and sedimentation deposition processes. In this work, we mapped and identified riparian zone vegetation along streams within the Neuse River Basin of Eastern North Carolina using Digital Orthophoto Quarter Quadrangles (DOQQs) that were created using National Aerial Photography Program (NAPP) 1:40,000-scale color infrared aerial (CIR) photography. The main objectives of this study were to create a comprehensive riparian buffer zone database and evaluate the use of high spatial resolution data for riparian buffer zone characterization. The database contains both image data and the attributes that were used for riparian vegetation analysis. These attributes include percent vegetation coverage, vegetation type, stream width, and shaded areas. The nature of the Neuse River Basin, which contains three main land cover categories; agricultural, urban, and forest in close proximity to streams, is used to demonstrate the predicting the effectiveness of land-use legislation on water quality.

Our results indicate that streams passing through agriculturally dominated landscapes have smaller vegetation buffers than streams flowing through other land-cover types. Additionally, we found higher levels of agricultural activity near first-order streams. Together, these two findings suggest that first-order streams may be more likely to contribute to water contamination. Overall results indicate that detailed buffer zone characteristics can be adequately mapped and monitored using digital CIR aerial photography. This allows researchers to study important stream water quality issues without extensive fieldwork, reducing the time and cost of these types of studies.