Wednesday, December 2, 2015

Cohasset eelgrass results

Here is the DEP map.  It was done by digitizing aerial photos flown in 2012 which were groundtruthed with underwater video.  Target scale 1:10,000.
84 acres of eelgrass (large meadow in the middle and small meadow to the southwest).

Here is our map. It was done by digitizing acoustic imagery collected in 2015 which we groundtruthed with underwater photos.  We used aerial photography to extend our survey to the north where we didn't have acoustic coverage.  Target scale 1:1,000. 
82.7 acres of eelgrass.  Since our survey didn't cover the northern part of this meadow, we double checked 2013 aerial photos to see that it was still there and then used part of the DEP 2012 delineation to add it on to our acoustic delineation.

Here are some photos to give an idea of what it looks like on the bottom:

Patchy eelgrass

Dense eelgrass

Granule-pebble bottom

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