How do you assess and mitigate the cumulative environmental impacts of future development? That’s the question that Marin’s environmental planners and contracted scientists have been analyzing in the San Geronimo Valley over the past decade, particularly related to the area’s threatened fish populations.

The effort was the result of a lawsuit brought by the Salmon Protection and Watershed Network in 2012. This week, Marin’s planning commission approved the final version of the document that details…