Issues

Lands within the Lower Subbasin are managed by RNSP;

Prior to 1978, approximately 68% of the landscape was harvested for timber resources;

The lower reach of Redwood Creek is a low gradient, depositional reach which accumulates excessive sediments derived from upstream sources;

Impairments to freshwater habitat needed to complete salmonid freshwater life cycles have been identified as a leading factors in the decline of Redwood Creek’s anadromous salmonids.

Findings

Lands within the Lower Subbasin are managed by RNSP:

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

The Lower Subbasin was made part of the Redwood National and State Park system in 1978.

Prior to 1978, approximately 68% of the landscape was harvested for timber resources:

Adverse impacts from legacy timber harvests are still affecting mainstem and tributary stream habitat.

The lower reach of Redwood Creek is a low gradient, depositional reach which accumulates excessive sediments derived from upstream sources:

The aggraded channel condition contributes to elevated water temperatures, a widened channel, and an overall lack of channel diversity and complexity in Redwood Creek;

During the summer months of recent low rain years (2001 and 2002) the lowermost reach of Redwood Creek became intermittent or dry from the Highway 101 bridge up to the confluence with Hayes Creek, loosing connection with the estuary. In a recent newspaper article in the McKinleyville Press (2002), it was noted by a local resident since 1945 that Redwood Creek has never been so low.

Impairments to freshwater habitat needed to complete salmonid freshwater life cycles have been identified as a leading factors in the decline of Redwood Creek’s anadromous salmonids:

Mainstem Redwood Creek summer water temperatures generally exceed favorable limits for salmonid production;

Anecdotal accounts by long time residents and CDFG reports indicate that water temperature was once much colder in Redwood Creek;

Lower Subbasin tributaries provide water temperature that supports salmonids;

A lack of instream large woody debris (LWD) contributes to poor aquatic habitat structure including a low number of deep, complex pools;

LWD recruitment potential to Lower Subbasin appears low at most locations;

Stream habitat conditions in the Lower Subbasin can be improved.

Recommendations

Barriers to Fish Passage

Modify or remove potential barriers such as deltas or boulder and/or debris accumulations that may impede upstream fish passage into tributary streams for spawning.

Flow and Water Quality Improvement Activities:

Promote near stream conifer growth to reduce solar radiation and to moderate air temperatures along stream corridors. This will reduce heat inputs to Redwood Creek and its tributaries and help to keep water cool.

Erosion and Sediment Delivery Reduction Activities:

Any reduction of sediment from upstream sources will benefit the lower mainstem Redwood Creek;

In order to reduce sediment delivery to Redwood Creek and its tributaries RNSP should continue efforts such as road improvements (e.g., upgrading crossings, rocking native surface roads, outsloping, ensuring surface drainage does not flow directly into watercourses, etc.) and decommissioning (e.g., removing unstable fills, removing drainage structures and fills, restoring natural contours, blocking vehicle access, etc.) throughout the Redwood Creek Basin;

To address accumulations of fine sediments observed in Elam, Bridge, and Forty-four creeks, Sediment sources from eroding stream banks and adjacent hillslopes should be identified and treated.

Riparian and Stream Habitat Improvement Activities:

Where appropriate, land managers should use tree planting, thinning from below, and other vegetation management techniques to promote the development of large near stream conifers along mainstem Redwood Creek, Bridge Creek or other steam reaches with a low coniferous component in the riparian zone. Thinning to encourage conifer growth should be done with consideration of maintaining adequate shade canopy over stream channels;

Instream LWD is needed for channel maintenance and shelter complexity;

Strategically add wood into pools and flatwater units to increase pool depth and overall shelter complexity in Bridge, and Elam, Forty-four creeks and other streams within the subbasin that lack deep complex pools;

Consider adding shelter complexity with wood to existing cool temperature refuge sites on Redwood Creek, and lower reaches of tributary sites. This could be done even on a temporary basis using small woody debris to provide escape cover for juvenile salmonids during summer season. The cool patches may be located in temperature stratified pools or adjacent to cool water inputs from tributary flows at Bridge Creek or near springs, and seeps.

Education, Research, and Monitoring Activities:

The range of habitat conditions within the Lower Subbasin provides an opportunity to monitor channel and salmonid habitat recovery rates using habitat improvement treatments within a variety of channel types and conditions;

Perform stream habitat surveys in tributaries throughout the Lower Subbasin to identify excessive erosion areas, assess salmonid stream habitat, identify deltas or boulder and/or debris accumulations that may impede passage for spawning, and to identify potential sites for improving habitat with restoration techniques;

Monitoring in-channel sediment by measuring sediment size distribution, turbidity, V*, photo points should be increased; tracking of streambed levels with stream channel cross sections should be continued along the mainstem reach of lower Redwood Creek;

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 Lower Subbasin streams;

Land managers and responsible agencies should increase continuous temperature monitoring efforts along the mainstem and at additional tributary locations to determine the impact of cold-water inputs from tributary and ground water sources;

Although there were no formal stream reach surveys for LWD; observations of crews and findings regarding pool complexity indicate that there is limited instream LWD. Formal surveys for LWD loadings could be done to verify these observations.