River mask before and after the Elwha dam removals, WA.

Two dams located on the Elwha River in Washington state were removed from 2011 to 2014. This resource contains a river mask prior to the removal in 2011 and three subsequent mask files from 2013, 2015, and 2017 showing the morphological evolution of the channel. The output river mask raster data were created using publicly available aerial imagery from the National Agricultural Imagery Program. First, supervised classification was performed to classify all water, non-water (vegetation, bare soil, and urban), water shadow, and non-water shadow pixels. The clear water and shadow water pixels were then reclassified as one, and finally, pixels around bridge cross sections, and additional misclassified pixels were manually corrected for each time period.