Recommendations

What watershed and habitat improvement activities would most likely lead toward more desirable conditions in a timely, cost effective manner?

Consider careful planning of land uses that could exacerbate mass wasting, since the relative potential of landsliding is high to very high in 60 percent of the subbasin;

Continue efforts such as road erosion proofing and decommissioning throughout the subbasin to reduce sediment delivery to Rockpile Creek and its tributaries. Focus efforts on roads and areas adjacent to the streams;

Encourage cooperative efforts to reduce sediment yield to streams. Grazing is an issue in the upper part of the subbasin. Bank stabilization is the third of the top three recommendations;

Encourage the use of cable or helicopter yarding on steep and unstable slopes to reduce soil compaction, surface disturbance, and resultant sediment yield;

Maintain and enhance existing riparian cover. Where current canopy is inadequate and site condition are appropriate, initiate tree planting and other vegetation management to hasten the development of denser and more extensive riparian canopy. Riparian canopy development is the second priority recommendation. The mainstem, Red Rock Creek and Horsethief Canyon are the primary areas needing attention;

Encourage the addition of more large organic debris and shelter structures in order to improve sediment metering, channel structure, channel function, habitat complexity, and habitat diversity for salmonids. Pool shelter is the most limiting factor in Rockpile Creek, the stream surveyed in the subbasin;

The natural large woody debris recruitment process should be enhanced by developing large riparian conifers with tree protection, planting, thinning from below, and other vegetation management techniques;

Instream structure enhancement is the first of the top three recommendations. Channel characteristics have improved the least in the Middle and Upper Rockpile Creek PWSs;

Encourage more stream inventories and biological surveys of tributaries, as only 39 percent of the subbasin has been completed;

Encourage continuation and expansion of the in-channel monitoring.

Conclusions

The Rockpile Subbasin has some of the steepest hill slopes in the Gualala Basin. The subbasin also appears to be one of the most impacted due to naturally occurring geologic processes and land use. Historic and current accounts show that steelhead trout inhabit subbasin streams, while no records document the presence of coho salmon. High instream sediment levels, high summer water temperatures, low canopy cover, simplified salmonid habitat, and limited amount of appropriately sized spawning substrate indicate that present conditions in mainstem Rockpile Creek are unsuitable for salmonids.

Accordingly, there are abundant opportunities for improvements in watershed stream and habitat conditions. These opportunities include reduction in sediment yield to streams, riparian canopy restoration, improvements to instream habitat complexity, such as large woody debris placement, and monitoring stream and fishery responses to these treatments. During project planning and design phases, careful consideration must be made concerning a proposed project’s watershed context, and proximity to unstable and erosive terrain. Additionally, best management practices must be followed to minimize erosion and sediment delivery to streams during project implementation.

Current landowners and managers interested and motivated to improve land use and accelerate a return to suitable watershed conditions and benefit salmonids are encouraged to do so. They are encouraged to enlist the aid and support of Gualala Basin improvement groups and agency technology, experience, and funding to accomplish these goals.