Middle Subbasin Overview

The Middle Subbasin represents a transition zone between the Coastal and Inland subbasins - moving from a heavily marine influenced climate and gentler slopes to larger temperature fluctuations throughout the year and steeper slopes. Although this subbasin is small, just under 10% of the land mass of the Big River Basin, it contains Two Log Creek, an important fish-bearing tributary. Salmon and steelhead habitat conditions in the Middle Subbasin are generally degraded, but support some salmonid production.

This subbasin appears to be impacted by reduced habitat complexity, high water temperatures in the mainstem Big River, and embedded spawning gravels. In addition, this subbasin has a comparatively dense network of roads that provide potential sources of fine sediment input to streams. Historical accounts indicate that stream conditions were favorable for salmonids in the past and certain habitat factors remain favorable in some of the tributaries. Accordingly, there are opportunities for stream improvements and a need to restore areas of stream refugia. Examples of habitat improvement activities include increasing channel complexity, monitoring temperatures, road improvements and erosion proofing, and mitigation of stream bank erosion. The natural variability of stability and erodability of the geologic terrains should be considered before project implementation and appropriate best management practices should be followed to minimize erosion and sediment delivery to streams. Current landowners and managers interested and motivated to eliminate impacts related to land use and accelerate a return to the stable, beneficial conditions for salmonids are encouraged to do so, enlisting the aid and support of agency technology, experience, and funding opportunities.

Big River - Middle Subbasin



Mainstem Big River (2002). Photo by Steve Cannata