Riparian areas in the Crown of the Continent Ecosystem

For the Crown of the Continent Ecosystem (CCE), the riparian ecosystem was classified using three existing layers: I) a streams network, II) a water class of the landcover layer, and III) a 22 meter digital elevation model (DEM).NOTE: There were minor issues with data integrity, as the water class of the landcover layer and the streams layer were not mutually exclusive: it was found that lakes were often represented as streams. (i) Stream network was rasterized (Polyline to Raster tool) after the features were dossolved. (ii) Rasters from each of the streams and lake classes are added together for full hydrology. Riparian classification systems are based typically on two to three characteristics, depending on the application (Lee et al 2004). Typically the water body type is separated into lakes and rivers, and then each class is separated into large or small lakes, and permanent or intermittent streams (Lee et al 2004). The existing streams network layer was found to be permanent, and the lakes included all sizes. However, the difference in riparian distances between lakes and streams specifically in the Rocky Mountains, regardless of size, were 23 and 24.4 meters respectively (Lee et al 2004). Because these measures were very close and were not significantly different (Lee et al 2004), the riparian distance was set to 24 meters. Riparian zones are further affected by terrain and local topography (Lee et al 2004). Rivers with steeper slopes receive larger riparian zones, and an increase of 0.79 meters per 1 degree increase in slope is an approximate measure of distance (Lee et al 2004). Therefore, a buffer of 24 meters covers slopes up to approximately 30.4 degrees. However the data becomes a significant limitation at this point due to the 22-meter resolution DEM. The initial buffer along the water bodies includes slightly more than one pixel on either side; the addition of another22-meter pixel, extending the buffer to 46 meters, includes 50.2 degrees of slope along the water body. Further riparian distances of 68 meters and 90 meters include 86.1 degrees and 113.9 degrees, respectively. The riparian distances are therefore restricted to the resolution of the digital elevation model, and include 24 meters, 46 meters, 68 meters, and 90 meters depending on adjacent slopes. This dataset was developed by the Crown Managers Partnership, as part of a transboundary collaborative management initiative for the Crown of the Continent Ecosystem, based on commonly identified management priorities that are relevant at the landscape scale. The CMP is collaborative group of land managers, scientists, and stakeholder in the CCE. For more information on the CMP and its collaborators, programs, and projects please visit: http://crownmanagers.org/References: Lee, P., Smyth, C., and Boutin, S. (2004) Quantitative review of riparian buffer width guidelines from Canada and the United States. Journal of Environmental Management 70: 165-180.