Issues

The Prairie Creek Subbasin is predominantly managed by RNSP;

Before RNSP was expanded to include 98% of the Prairie Creek Subbasin, approximately half of the subbasin was logged using timber harvest practices that resulted in disturbance to salmonid habitat;

Impacts from Prairie Creek Hatchery operations;

Sediment impacts from the Highway 101 bypass are a concern.

Findings

The Prairie Creek Subbasin is predominantly managed by RNSP:

RNSP management goals include the protection of natural resource values including anadromous salmonids and their habitat;

The Prairie Creek subbasin supports self sustaining populations of Chinook, coho, steelhead, and coastal cutthroat trout;

The Prairie Creek Subbasin likely supports the largest coho salmon population of the Redwood Creek basin;

The RNSP is a World Heritage Site and is part of the California Coast Range Biosphere Reserve, designations that reflect worldwide recognition of the parks’ natural resources as irreplaceable;

The RNSP has done a significant amount of work to survey road systems, identify problems, and implement road removals and upgrades that should result in reducing erosion and sediment inputs into stream channels;

Much of the upper watershed of Prairie Creek and Little Lost Man Creek watersheds are relatively undisturbed areas. These areas retain old growth forest characteristics and provide some of the highest quality fisheries habitat within the Redwood Creek basin.

Before RNSP was expanded to include 98% of the Prairie Creek Subbasin, approximately half of the subbasin was logged using timber harvest practices that resulted in disturbance to salmonid habitat:

Impacts from past timber harvest still effect some riparian and stream habitat;

Debris accumulations on Lost Man Creek may impede anadromous fish passage to upstream spawning grounds;

Lost Man Creek watershed still has a relatively high density road network;

It appears that land use has exacerbated landsliding in the Lost Man Creek Planning Watershed and the landscape has not fully recovered from past disturbances.

Impacts from Prairie Creek Hatchery operations;

Steelhead/rainbow trout were introduced from other basins.

Sediment impacts from the Highway 101 bypass are a concern:


Surface and drainage alterations associated with the construction of the Highway 101 bypass resulted in the generation and delivery of large quantities of fine sediments into headwaters of tributary streams. Salmonid spawning and rearing habitat of Prairie, Brown, Boyes, and May Creeks were affected by the event.

Recommendations

Barriers

Modify large debris accumulation on Lost Man Creek to improve passage of spawning adults.

Flow and Water Quality Improvement Activities:

Ensure that adequate streamside protection measures are used to maintain shade canopy in order to reduce moderate inputs to the lower reach of Prairie Creek and to maintain good water temperature in Lost Man Creek and other tributary streams;

Water flow or water quality does not appear to be and issue at this time, but fish habitat requirements and channel maintenance flows should be considered prior to any water development projects.

Erosion and Sediment Delivery Reduction Activities:

Continue road assessments and upgrades or removal of roads, especially in the Lost Man Creek planning watershed;

Work with CalTrans to reduce sediment input potential to streams from HWY 101 activities;

Consider bank stabilization projects in the Lost Man Creek watershed.

Riparian and Instream Habitat Improvement Activities:

Restore riparian function in areas where vegetation removal or significant cattle impacts have been noted in lower Prairie Creek;

Consider modifying debris accumulations in Lost Man Creek to facilitate fish passage;

Consider adding pool enhancement structures to increase the number of pools or deepen existing pools in Lost Man Creek, May Creek, and Boyes Creek.

Supplemental Fish Rescue and Rearing Activities:

The use of Prairie Creek hatchery can be considered to supplement fishery resources of Redwood Creek if populations fail to respond to current management strategies.

Education, Research, and Monitoring Activities:

The wide range of habitat conditions within the watershed provides an opportunity to monitor channel and salmonid habitat recovery rates under various habitat improvement treatments within a variety of channel types and conditions;

Humboldt State University and RNSP should continue and expand their salmonid population and continuous temperature monitoring tasks in the Prairie Creek subbasin. This includes the use of fish counting weirs, spawner and redd surveys and juvenile population studies;

A long term, concerted monitoring effort between the land owners, interested parties and responsible agencies is needed to determine the status and trends of anadromous fish populations in the Prairie Creek Subbasin;

Water temperature monitoring should occur at the confluence of Prairie Creek and the mainstem to determine the effects of colder Prairie Creek water on the mainstem and estuary;

Nutrients contributed to streams from eggs and decaying carcasses has declined. Studies should be conducted to discern relationships between nutrient contributions from carcasses, stream productivity, and salmonid production;

Ensure that any land management activities include protection and preservation of stream and riparian habitats;

CalTrans should continue to monitor and reduce sediment delivery from the Highway 101 bypass.