Assessing Riparian Condition using GIS and Remote Sensing
Riparian areas provide a multitude of ecosystem functions, including water quality improvement, sediment removal, nutrient cycling, bank stabilization, and flood reduction. While these habitats provide a wide range of benefits to human communities, the loss and impairment of riparian lands in Alberta has been significant, and recent watershed management efforts throughout the province have been focused on identifying priority areas for riparian restoration and habitat management. In order to efficiently target restoration efforts and resources, however, there first needs to be reliable information about the location, condition, and function of riparian habitats. That’s why Fiera Biological Consulting has been developing methods for assessing riparian condition using GIS (geographic information systems), and remote sensing.
At present, there is little information about the location and extent of riparian habitat in Alberta, and the condition of these habitats is typically assessed at a site-specific or reach-scale using either ground-based surveys, airborne videography, or stereo air photo interpretation methods. These approaches tend to be labour intensive and costly, and often rely on subjective and qualitative metrics to assess the condition of riparian vegetation. While these methods are useful for gathering information about the general condition of riparian habitat at small spatial extents, there is a need for a more rigorous and objective approach to riparian condition assessments. Further, developing reliable and cost-effective methods that allow for the standardized assessment of riparian condition at different spatial resolutions (e.g., very detailed and fine-scale versus general and coarse-scale), and that can be tailored to the type and quality of available data (e.g., expensive and high resolution versus freely available and lower resolution) is an important step in improving riparian management outcomes across the province.
Given the large area of riparian habitat within Alberta, Fiera Biological responded to the pressing need to develop a riparian assessment method that is rapid, reliable, repeatable, comparable, and objective. This GIS-based assessment method allows for a general assessment of riparian intactness for stream and lake shorelines using land cover layers derived from satellite data, thereby allowing for the assessment of riparian areas over large spatial extents. This approach provides an overview of the status of riparian condition at the watershed scale, thereby giving land managers a tool that identifies areas on the landscape that may require special management, or should be targeted for riparian habitat restoration or conservation. This information can be used to spatially target areas along the river shoreline for restoration, and also provides data that can be used as a foundation for tracking change in riparian area intactness through time.
To-date, this method has been used to assess riparian intactness for more than 6,500 km of lake, stream, and river shoreline in the North Saskatchewan and South Saskatchewan River basins. The method has also been validated using both aerial videography and field data, and this validation work indicates that the GIS method provides reliable estimates of riparian condition for lakes and streams across a range of conditions and geographies.
The North Saskatchewan Watershed Alliance has recently made public some of our riparian assessment reports, you can check them out at links below.
If you are interested in learning more about this method, or would like to discuss the opportunities for using this method to assess riparian areas in your watershed or municipality, please get in touch!
North Saskatchewan Watershed Alliance (NSWA), Alberta Environment Parks, and others.
2016 to 2018