Mainstem South Fork Subbasin Overview

The Gualala Mainstem/South Fork Subbasin contains 134 miles of “blue line” stream in its 63.7 square mile watershed. The river system originates in the far southern end of the Gualala River Watershed and flows north as an alluvial stream along the San Andreas Fault to meet the North Fork Gualala. From that point to the ocean, the stream is considered the Gualala River mainstem. The upper reaches flow from steeper terrain outside the San Andreas Fault zone. About 50 percent of the subbasin is categorized as high to very high landslide potential. Nearly all of the subbasin is privately owned, with 15 acres of federal land and 38 acres of state land. Predominant land uses are timber production, grazing, and small vineyards.

Gualala River - Mainstem SF Subbasin