Applying a buffer to stream segments is a quick and easy method for approximating riparian extent.
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Buffering is a useful tool to quickly and easily approximate riparian extent by applying a buffer to a vector stream dataset, such as National Hydrology Dataset (NHD) streamline data. There are two types of buffers: simple and smart.
A simple buffer applies a constant buffer to all stream segments in the study area. This is the least exact approach, but might be suitable when complying with requirements to establish a default width for riparian areas in the absence of better scientific information.
Smart buffers offer a more sophisticated approach by varying the buffer width according to the size and nature of the stream. There are a variety of parameters that can be used to vary buffer width; however, Rosgen level and Strahler stream order are commonly used. Both of these parameters can be estimated directly from GIS data. A table or matrix is created with a buffer width for each Rosgen level-Strahler order combination. In general, the lower level/order combinations have relatively narrow floodplains and therefore the buffers that represent these features increase as the level/order combination increases. The width of the buffers is based on a generalized estimation of the riparian width by an individual familiar with the study area.
- Stream line data (e.g. NHD data)
- Digital Elevation Model (DEM)
Buffer methods generate a set of polygons that delineate a fixed distance around each stream segment that can be used as a proxy for riparian mapping.
Riparian Application Example
Evans, D.; Vanderzanden, D.; Lachowski, H. 2002.
- Low accuracy
- ESRI’s ArcGIS