Maps: Didymo Locations and Survey Sites

Didymo was found in early 2008 in Gunpowder Falls below Prettyboy Reservoir in Baltimore County. Since July 2008, DNR and Baltimore County/DEPRM have been monitoring Didymo occurrence monthly in the Gunpowder Falls between Prettyboy and Loch Raven reservoirs.

Below are maps containing Didymo locations and survey sites by month.