Issues

Salmonid populations have declined from historic levels, prompting listings under the state and federal ESA’s.

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.

The Middle Subbasin terrain is highly susceptible to erosion.

Land management can influence watershed processes.

Riparian and near stream forests have been altered by timber harvests and bank erosion.

What are the impacts from Chezem dam on Redwood Creek and salmonids?

Findings

Salmonid populations have declined from historic levels, prompting listings under the state and federal ESA’s:

There is a decline in abundance and distribution of coho salmon and coastal cutthroat trout in the Middle Subbasin;

Coho salmon were not observed in 2001 fish surveys;

The summer steelhead population has declined to critically low levels of abundance;

Chinook salmon show variable spawning success among years.

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:

Mixed conditions for salmonid spawning and rearing success exist in the subbasin;

There is a lack of shade canopy along mainstem Redwood Creek;

High summer water temperature along the mainstem Redwood Creek and lower reaches of Lacks and Minor creek impairs juvenile rearing habitat and adult holding habitat for summer steelhead;

There is a lack of deep and complex pools in tributary streams and mainstem Redwood Creek;

A lack of instream LWD impairs fish habitat;

Stream habitat conditions in the Middle Subbasin can be improved.

The Middle Subbasin terrain is highly susceptible to erosion:

High potential exists for large sediment inputs from disturbed and unstable hillslopes;

High levels of sediment are stored in mainstem and some tributary channels;

Historically active landslide features cover 4,200 acres (6.5%) of the subbasin. These features are critical sources of sediment inputs to stream channels.

Land management can influence watershed processes:

Land use has made the Middle Subbasin’s terrain more susceptible to erosion;

High road density of both abandoned and useable roads adds to sediment delivery potential;

Debris slides and debris flows are often initiated by management activities (such as road construction) that take place on existing earthflows or rockslides.

Riparian and near stream forests have been altered by timber harvests and bank erosion:

Timber harvests have caused significant levels of disturbance to riparian and near stream forest areas causing a reduction in both overstory shade canopy and LWD input potential;

In response to aggraded channels, stream banks erode, channels widen, and riparian vegetation becomes less affective to provide shade over the water.

Recommendations

Barriers to fish passage

Investigate improving fish passage through 500 foot long culvert under HWY 299 on Lupton Creek;

Modify sediment deltas or boulder accumulations that impede upstream migration into tributaries. A sediment delta formed by boulder accumulations is located within the lowermost reach of Panther Creek and possibly other tributaries;

Modify large debris accumulations that may impede fish passage on Panther Creek and other tributaries (completed by Green Diamond and the California Conservation Corps in 2004).

Flow and Water Quality Improvement Activities:

Reducing water temperature is essential to improve anadromous salmonid habitat in the Middle Subbasin. A long term goal should be to reduce water temperature in the middle reach of Redwood Creek and the lower reaches of tributary streams including Panther, Coyote, Minor and Lacks creeks;

A reduction in temperature will likely occur as the result of increasing pool frequency and depth, controlling erosion, increasing the coniferous component of the riparian zone and allowing near stream conifers to obtain large size for development of microclimate benefits;

Functional nearstream conifer forests need to be developed and/or maintained along Redwood Creek in the Middle Subbasin. Large near stream conifers are needed to help increase shade canopy, moderate air temperatures, and to promote LWD loading. This may require more than the minimum protection provided by present Forest Practice Rules;

Increase shelter complexity in existing cool water refuge sites;

Managers should explore methods to develop cool water refuge sites on Redwood Creek and the lower reaches of Panther, Lacks, and Minor and other creeks. Methods should include using pool scour elements, and increasing connectivity to cool ground water sources.

Erosion and Sediment Delivery Reduction Activities:

In streams where the majority of pool tail spawning substrate is highly embedded with fine sediment, sediment sources should be located, rated according to their potential sediment yields, and treated;

Upgrade or decommission roads in accordance with existing or future road assessment surveys. This work should be done especially on older roads built below current standards on unstable slopes and roads near streams in Upper and Lower Lacks, Minor, Lupton, Panther, and Coyote and Roaring Gulch planning watersheds;

For timber management in Lacks, Minor, Coyote and other planning watersheds, with active landslides or on steep and/or potentially unstable slopes (slopes ≥ 35%) we recommend the use of lower impact silvicultural prescriptions to maintain vegetative cover, root strength, and the use of cable systems or helicopter yarding to reduce the potential for mass wasting and sediment production;

Land management activities adjacent to all streams, particularly in the inner gorge, head walls, and on slopes 35% (19 degrees) or greater, must be carefully evaluated and designed to avoid generation and delivery of sediment to stream systems;

Timberland managers should decrease the use of tractor or ground lead yarding on all slopes steeper than 35% (19 degrees); and use fully suspended (skyline) cable or helicopter yarding on steep and unstable slopes;

RNSP and private landowners 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 reduce sediment delivery to Redwood Creek and its tributaries;

A qualified, licensed geologist or engineer should be consulted before initiating any project that involves road construction, timber harvest, or building. The NCWAP Landslide Potential maps should be reviewed before modifying hillslopes to avoid creating, or contributing to, hillslope instability and excessive, human-induced erosion through mass wasting or creation of gullies.

Riparian and Stream Habitat Improvement Activities:

To increase overstory shade and to promote input of large woody debris, encourage near stream conifers to grow to large sizes and retain them along Redwood Creek and all tributary streams in the subbasin;

Where there is adequate shade canopy along Lacks, Minor, Molasses, and Coyote Creeks, land managers should consider thinning hardwoods from below in riparian areas to hasten the development of large near stream conifers;

Trees large enough to function as LWD need to be allowed to grow and recruit to stream channels from riparian and near stream forest areas.

Consider adding pool forming structures to increase the number of pools in Redwood, Lacks, Minor, Lupton, Molasses, Panther, Mill, and Beaver creeks;

Deepen and increase the size of existing pools in Dolly Varden, Toss Up, Garret, Lupton creeks and in lower reach of Coyote Creek;

Add wood into pools and flatwater units to increase shelter complexity especially where the average size of near stream conifers is less than 2 feet DBH in Redwood, Lacks, Minor, Lupton, Panther, Coyote and Molasses creeks;

Consider adding shelter complexity to existing temperature refuge sites on Redwood Creek.

Education, Research, and Monitoring Activities:

Water temperature monitoring should continue at the current locations to observe changes in temperature as effects from aggradation, degradation, channel widening, and riparian condition adjust over time;

Identify potential perched sediment deltas and/or debris accumulations that may impede passage for spawning into Panther Creek and other Middle Subbasin tributaries;

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

Investigate impacts from fine sediments on salmonid spawning success and aquatic insect community structure;

Formal stream reach surveys were not done for LWD; however observations of crews and findings regarding pool complexity indicate that there is limited instream LWD. Formal survey for LWD loadings could be done to verify these observations;

Monitoring in-channel sediment routing and storage(e.g., sediment size distribution, turbidity, V*, photo points, etc.) should be increased and tracking of streambed levels (i.e., stream channel cross sections) should be continued;

Summer steelhead dive counts should be conducted on an annual basis on the middle reach of mainstem Redwood Creek and in the lower reach of Lacks and Minor creeks;

Continue monitoring juvenile fish population trends such as downstream migrant trapping operations on mainstem Redwood Creek;

Investigate possible improvements to cool water refugia and potential to increase such areas;

Further study of the effects of Chezem summer dam on fish and fish habitat is warranted;

Ensure that CEQA-compliant environmental assessment is conducted prior to issuance of the Fish and Game Code 1603 streambed alteration permits and Corps of Engineers or NOOA Fisheries permitting requirements are complete for any summer dams on Redwood Creek.