This study evaluates the effectiveness of mult-temporal Synthetic Aperture Radar (SAR) data in combination with Landsat ETM+ imagery to delinate:
    1.  The locations of Salix alaxensis along the Innoko River corridor.
    2.  The locations of lakes within the Iditarod River drainage that have a connection to a river during normal water level conditions.

Both elements are related in that they constitute critical habitat for several different species of wildlife on the Innoko National Wildlife Refuge, and that their occurrence is largely due to seasonal flooding.

Multitemporal, georeferenced Radarsat SAR imagery was used to monitor the pattern of water recession in order to classify lakes into two categories: drawdown and non-drawdown .  Lakes larger than 1 hectare that experienced a change of less than -15 percent between a period of normal and low water level conditions were classified as "draw down", all others were classified as "non-drawdown".  This simple technique yielded an overall classification accuracy of 80 percent.  Thus multitemporal, georeferenced SAR data are useful for delineating drawdown lakes in the study area.

Landsat ETM+ imagery was used to develop three criteria (proximity to: 1) turbid water, 2) broadleaf vegetation, 3) sandbars) to aid in the delineation of Salix alaxensis.  Areas that met all three of the criteria had an estimated user's accuracy of 16 percent and an estimated producer's accuracy of only 4 percent.  Thus the relatively large pixel size (25m) of Landsat ETM+ made this type of satellite imagery ineffective for mapping narrow riparian willow communities.
 
 

 email: ftjlf@uaf.edu