Coastal Subbasin Overview

The Coastal Subbasin contains the Big River Estuary, which is of major importance to fish and wildlife along the Mendocino coast. The estuary provides a large area of wetlands that are essential habitat to many species including salmonids. Salmon and steelhead habitat conditions in the estuary, the mainstem Big River, and the tributaries of the Coastal Subbasin are generally in the early stages of recovery from past disturbance and suitable for salmonid production. Reduced habitat complexity, high water temperatures in the mainstem Big River, and embedded spawning substrate are limiting factors to salmonid populations in some parts of the subbasin.

There are many opportunities for improvements in conditions, especially with the recent creation of the Big River State Park. Water temperature monitoring, road maintenance and decommissioning, and adding LWD to improve channel complexity are examples of appropriate improvement activities that can be initiated in the park.  However, aquatic and channel conditions at the most downstream section of a river system are a response to watershed products transported from throughout the basin. Fine sediment and warm water are two watershed products most deleterious to the estuary’s fisheries. As such, long term improvements in the estuary must be produced by careful watershed stewardship throughout the Big River Basin.