Watershed Approach Taken by Klamath and Trinity Restoration Programs
The Long Range Plan for the Klamath River Basin Conservation Area Fishery Restoration Program (USFWS, 1991), which guides the Klamath River Task Force, recognized that watershed restoration must take precedence over treatments of stream channels. The Plan insures that in-stream structures are considered holistically by making them meet the following criteria before they can be considered for funding under the Klamath River Restoration Program:
* Proposals must demonstrate that sediment yield in moderate storm events (10 year interval or less) is not expected to place the project at risk,
* Aggradation at the project site must be shown not to effect potential stability of structures,
* Flow and gradient have been considered to insure that structures are properly engineered,
* Habitat typing of the basin to be treated has been conducted and suspected limiting factors identified
,* The project is geared to remedy identified limiting factors,
* An evaluation program is in the budget that can show whether or not the project goals have been achieved.
Figure 10-2. Trinity River Task Force flow chart for tributary rehabilitation (USFWS, 1988c). NOT AVAILABLE IN ELECTRONIC FORMAT
The Trinity River Restoration Task Force has also changed its criteria for approval of instream structural treatments in recent years, requiring consideration of watershed conditions and placing a greater emphasis on upslope erosion control (Figure 10-2). The Task Force now requires that habitat typing surveys be completed before projects can be considered. Surveys provide baseline information before treatments are applied, and can also be used to help unmask potential limiting factors for spawning or rearing which might suggest specific structural treatments. A well defined evaluation is also required for any instream habitat improvement project funded by the Trinity River Fish and Wildlife Restoration Program.
Federal Agencies To Restore Watersheds to Protect Pacific Salmon
In July of 1993, the Report of the Federal Ecosystem Management Assessment Team (FEMAT, 1993) was released in response to the northern spotted owl crisis. The report recognized that Federal forest lands must be managed so as to prevent further habitat declines for Pacific salmon stocks and thereby avoid the need for listing under the Endangered Species Act. The FEMAT (1993) report calls for $185 million in expenditures to reduce erosion risk in Key Watersheds, which are refuges for salmon and steelhead stocks. Riparian restoration is also being pursued to help restore ecosystem function to cold water streams.
Limitations of Habitat Typing For Determining Restoration Measures
It has been a common assumption in habitat typing reports that some physical features of the stream habitat are limiting rearing capacity of juvenile salmonids in South Fork Trinity River tributary basins (Frink et al., 1990; Mayo et al., 1992). Reports typically note habitat preference of various age classes of steelhead, termed electivities (Jacobs, 1974), and suggest that structural treatment can increase fish densities. We believe this approach does not fully consider necessary ecological elements needed to determine fundamental limiting factors on fish populations.
While juvenile salmonids in many South Fork Trinity River reaches or tributaries do show higher association for some habitat types, no such preference was exhibited by fish in Big French Creek, a near pristine tributary to the main stem of the Trinity River (Cross, 1989). Steelhead of all age classes were distributed fairly evenly in pools, riffles, and runs (Figure 10-3). This suggests that, if water temperatures are cool and food abundant is restored in South Fork Trinity tributaries, that all age classes of steelhead fish might be almost equally distributed throughout all habitat types.
Habitat typing surveys in the South Fork are finding many juvenile steelhead in high gradient riffles or cascades. We believe this is due to increased dissolved oxygen levels and not because of affinity for any other element of that habitat. This should suggest that stream temperatures need to be cooler, not that we need to create more of this habitat type. Frink et al. (1990), based on habitat typing surveys conducted in June, suggested that cover structures were needed in glide habitats on Hayfork Creek to attract young of the year steelhead. This recommendation did not factor in the likelihood of stressful or lethal, higher stream temperatures which would occur later in the summer. While habitat typing is a very useful inventory tool, using survey data to identify limiting factors and to suggest restoration activities may have limitations.
Figure 10-3. Juvenile steelhead distribution by age class in pools,riffles, and runs in all reaches of Big French Creek. NOT AVAILABLE IN ELECTRONIC FORMAT
Almost all remediable problems for fish passage in the South Fork Trinity River basin, either man-made or natural, have been resolved. The only exceptions are periodic problems with small seasonal dams, and possibly the East Fork Ranch diversion on Hayfork Creek.
A considerable amount of resources have been spent on instream habitat improvement projects to date (Plate 3). Past floods have altered the quality of habitat in many South Fork Trinity River tributaries along almost their entire length. Work by Reeves et al. (1988) suggests that only after a large portion of stream habitats are altered can any change in juvenile salmonid production be expected. Frissell and Nawa (1992) show that all investments in stream channel alteration may be subject to high failure rates even in moderate storm events. This makes such work a questionable investment. A major re-evaluation of the use of instream structures should take place. It should be based on a full physical and biological evaluation of completed projects.
Another factor leading to a transition in the South Fork Trinity River basin away from instream habitat improvement structures is the diminishing number of appropriate sites that lend themselves to treatment (Gary Flosi, personal communication). The steep rugged terrain prevents access to many of the remaining tributary basins might be candidates for treatment, particularly since projects in larger tributaries often require heavy equipment. Impacts to spotted owls adjacent to sites where treatments are proposed are also inhibiting project development. Consequently, project planning by the CCC has become much more expensive and implementation may be delayed considerably. We encourage the CCC to seek out new types of restoration opportunities such as upland watershed stabilization and riparian restoration.
If resources for restoration work are limited, actions to address root problems such as sedimentation, water flows and water quality should take priority. Erosion control and watershed restoration have been carried out in response to fire damage, and more work is planned to prevent erosion and allow stream channel recovery. It may be most cost effective to spend available resources on watershed projects which reduce sediment inputs into stream channels, and let hydrologic processes naturally restore fish habitat through scour and flushing. Once sediment sources are decreased, further implementation of instream structural projects may be warranted.
Riparian restoration has only been implemented on a pilot program basis but it shows great potential. Whether in main river habitats, steep forested streams, or alluvial reaches through agricultural land, it will be critical to determine the "desired future condition" of riparian zones and make a long term commitment to restore them.
Some water conservation measures have been implemented in the Hayfork Valley, but additional water conservation projects may have the greatest potential of all available restoration tools. If cold water flows are restored to Hayfork Creek during summer, it could produce an abundance of steelhead juveniles, and potentially serve as a refuge for spring chinook and summer steelhead adults. The channel of lower Hayfork Creek is largely unchanged as a result of past floods, yet the current lack of flows and high water temperatures during summer months pose fundamental ecological problems for fisheries. This stream produced trout and steelhead juveniles in phenomenal abundance as recently as the early 1960's.
It is apparent that watershed and fish habitat problems in the South Fork Trinity River and its tributaries can only be remedied through public cooperation and participation. In order to win that cooperation, a strategy must be devised that benefits landowners as well as salmon and steelhead resources.