Recommendations

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

Landowners should develop erosion control plans for decommissioning old roads, maintaining existing roads, and constructing new roads. Target road upgrade and repair in the areas identified above;

Incorporate mitigation elements into Timber Harvest Plans in the timber dominant Lower Wheatfield SPWS to decommission historical streamside roads and upgrade road drainage facilities;

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;

Decommission and revegetate streamside roads, focusing on those where channel braiding and/or aggradation are present;

Pursue cost sharing grants to upgrade appurtenant ranch roads in the Walters Ridge and Hedgepeth Lake SPWSs;

Reduce livestock and feral pig entry and subsequent impacts to the riparian zone to encourage stabilization of stream banks and re-vegetation of the riparian zone. These impacts are most common in Danfield, House, Pepperwood and Tombs creeks;

Retain, plant, and protect trees to achieve denser riparian canopy cover where current canopy is inadequate. Ensure that adequate streamside protection zones are used on the Wheatfield Fork and tributaries to reduce solar radiation and moderate air temperatures, particularly on the mainstem and upper tributaries;

Encourage the addition of large organic debris and shelter structures in order to improve sediment metering, channel structure, channel function, habitat complexity, and habitat diversity for salmonids;

Encourage more habitat inventory surveys and biological surveys of tributaries, as only 45 percent of the subbasin has been completed;

Evaluate canopy composition and monitor air temperatures to examine canopy, temperature, and other microclimate effects on water temperatures;

Conduct both instream and hillslope monitoring to determine whether current land use practices are allowing for recovery and protection of the salmonid habitat in the subbasin;

Expand continuous temperature monitoring efforts into the upper subbasin and tributaries.

Conclusions

The Wheatfield Fork Subbasin is characterized by steep tributaries flowing into the mainstem Wheatfield Fork, which is dominated by bedrock and a relatively narrow floodplain. Large areas of active earthflows and other forms of landsliding are abundant and contribute sediment directly into subbasin streams. These relatively high sediment levels can be attributed to both natural and human land use disturbances. For example, road building adjacent to stream channels or across debris slide slopes and/or steep terrain has also contributed sediment to streams.

Historic and current accounts show that steelhead trout inhabit the subbasin, while only one record described coho salmon on Haupt Creek in the 1960s. Relatively high instream sediment levels, simplified salmonid habitat, low levels of instream woody debris, open canopy cover, and a lack of appropriately sized spawning substrate indicate that present conditions are unsuitable for salmonids. Nonetheless, air photos indicate instream and near stream conditions have improved since 1984.

There are abundant opportunities for improvements in watershed stream conditions. Control measures for access to streams by livestock and feral pigs, improvements to instream complexity, such as additional large woody debris, increased riparian canopy density, and monitoring physical and biological responses to these treatments, are examples of appropriate treatments. During project planning and design, careful consideration of the watershed context and the proposed site’s proximity to unstable and erosive terrain must be made. During project implementation, appropriate best management practices should be followed to minimize soil disturbance and potential sediment delivery to streams.

Current landowners and managers interested and motivated to eliminate impacts related to land use and accelerate a return to suitable conditions for salmonids are encouraged to do so, enlisting the aid and support of Gualala restoration groups and agency technology, experience, and funding opportunities.