Below are some images from a Survey of Lagunitas Creek. done by Michael Sturtevant and other members of the One TAM EDRR team over several days in late July, 2019.

The surveyors were looking for Fallopia japonica (Japanese knotweed) and Hypericum grandifolium (Malfurada).

Yellow dots represent observations of these two plants made by the surveyors. The violet polygon shows the area they covered during the survey. Zooming in close, you can see the actual paths they took. (In the first image below, it almost looks like alien writing.)

Here is the whole area covered by the survey: