Fish Ladders and Screens for Agricultural Diversions
Diversion structures can sometimes pose migration problems for adult and juvenile salmon and steelhead. However, most problems of this nature in the South Fork Trinity River basin have been remedied (Cal Crawford, personal communication). The California Department of Fish and Game screen shop in Red Bluff operates and maintains fish screens on most large diversions, many of which have been installed for decades (Table 10-2) (Quelvog, 1981). Thousands of juvenile steelhead are rescued annually from upstream of diversion screens and safely transported downstream or used in the small scale pond rearing program (Darryl Yount, personal communication). In the 1960's, these fish salvage operations trapped 250,000 to 300,000 juvenile steelhead per year, but in recent years only a few thousand have been rescued (Cal Crawford, personal communication).
Passage around permanent diversion dams for spawners has been established with fish ladders. On Big Creek, the diversion dam for Big Creek Ranch and the Trinity County Water District has a fish ladder made out of concrete steps. McCaslin (1986) built a series of cement jump pools to assist passage over an agricultural diversion on lower Olsen Creek near Hyampom. A fish ladder has also been constructed to provide passage by a large diversion structure on Tule Creek.
Table 10-2.
Fish Screens Installed in South Fork Trinity River Tributaries Including:
Installation Date, Season of Operation, Flow Diverted and Bypass Flows
(From Quelvog,1981)
Fish Screen Stream Year Months Water Bypass
Installed Operated Diverted Flows
Lower Big Cr. Big Cr. 1951 May-Oct. 10 cfs 0
Upper Big Cr. Big Cr. 1971 May-Oct. 16 cfs 1 cfs
Carr Creek Carr Cr 1979 May-Oct. 2 cfs 0
Jackson Ranch Hayfork 1967 May-Oct. 6 cfs 0
Sheil Ditch Hayfork 1965 May-Oct. 6 cfs 0.5 cfs
Little Cr.1 Little Cr 1968 May-Oct. 2 cfs Unknown
Salt Creek Salt Cr. pre-1954 May-Oct. 6 cfs 0.5 cfs
Tule Creek Tule Cr. 1952 May-Oct. 4 cfs 0
Upper Tule Tule Cr. 1979 May-Oct. 2 cfs 0
1 Little Creek diversion is currently inoperative (Cal Crawford, personal communication)
A more common way of diverting water is through use of seasonal dams using gravels, plastic liners, boards or other materials. These small earthen dams wash out with high flows so don't often pose problems for migration of adult salmon and steelhead. Juvenile salmonids face more of a challenge in getting by seasonal diversion structures. Trinity Fisheries Consulting (1989) conducted an inventory and assessment of water diversion and associated structures in the Trinity basin including the South Fork Trinity River and Hayfork Creek. Their report indicated that seasonal and permanent dams often lack notches or spillways to allow downstream migration of juveniles. They also pointed out that material for seasonal dams should be removed before rains to reduce sediment entering stream systems. Trinity Fisheries Consulting (1989) suggested that small diversions with high suction should be studied for their potential impact on downstream migrants.
Additional needed action for mitigation of problems posed for fish passage by diversion structures were described for the following creeks: Pelletreau, Kerlin, Rusch, Little, Tule, West Tule, Salt, Carr, Duncan, Hayfork, and the East Fork of Hayfork. However, problems identified above have almost all been remedied at this time (Cal Crawford, personal communication). In drought years, downstream migrant traps are operated to see if fish screen installation is necessary. If no juvenile salmonids are present, no fish screens are installed.
On Pelletreau Creek, a mini-screen is installed by CDFG in years when juvenile steelhead are found. A tube screen with appropriate mesh was installed on the diversion in Kerlin Creek. The gravel dam on Rusch Creek has been replaced by a gabion weir, constructed by the USFS, and notched in the middle to allow fish passage. The diversion on Little Creek has not been active for several years but improvements for screens and fish passage will be required if it is re-activated. All problems for other tributaries named above have been similarly remedied (Cal Crawford personal communication).
One noted exception is the diversion for the East Fork Ranch on Hayfork Creek. CDFG contends that the weir spanning Hayfork Creek that serves as the diversion headworks is a migration barrier. The California Fish and Game Commission has held a hearing on this problem in Hayfork and CDFG is pursuing legal action to abate this problem, however, some type of fish ladder was installed by the land owner in 1992 . Also, the lowest diversion dam on Barker Creek, above its convergence with Carr Creek, lacks a screen and two other dams on Barker Creek inhibit migration of steelhead in low flow years.
Use of Instream Structures to Improve Salmon and Steelhead Habitat
Over the last decade, fisheries managers have showed renewed interest in directly altering stream channels to increase their fisheries potential (Hassler, 1984). Both the Model Steelhead Stream Demonstration Program (Irizarry et al., 1985) and the South Fork Trinity River Salmonid Habitat Enhancement Studies (CDWR, 1982) endorsed substantial use of in-stream habitat improvements. Many of the projects that were envisioned in these plans have been installed by the CCC (Flosi, 1992) with funding from CDFG, Shasta-Trinity National Forest, and the Trinity River Task Force. Log or rock weirs have been constructed to trap spawning gravels and to create scour pools. Boulder groups and woody elements have been placed in streams to scour pockets or provide cover for salmon or steelhead. Banks have also been stabilized through use of rip-rap (large rock) or logs. Table 10-3 lists the types of structures that have been installed in various streams in the South Fork Trinity River basin.
Much of the instream fish habitat improvement work done in South Fork Trinity River tributaries has been to improve pool depth and cover. Actions have been based on preliminary habitat typing surveys on Tule Creek (Laird and Barnard, 1988) where it was found that yearling and two year old steelhead juveniles favored pools with greater depth and better cover. High water temperatures have severely restricted suitable habitat for older age juvenile steelhead in the main stem of Hayfork Creek, and in the South Fork Trinity River. For this reason, fish habitat improvement projects have been aimed at increasing tributary habitat (Gary Flosi, personal communication). Adult steelhead scales show that unless juveniles stay in freshwater for two years, their survival in the ocean is poor (Mills and Wilson, 1991; Wilson and Mills 1992). By creating additional suitable habitat for older age juvenile steelhead in tributary streams, it is hoped more will survive and return as adults.
Installation of instream structures increased substantially after 1985 in the South Fork Trinity River basin (Flosi, 1992). In addition to the CCC work force, the USFS directly employed crews to install fish habitat improvement projects in 1988-1990. The CCC relies heavily on CDFG for technical expertise and, conversely, CCC labor has often been funded by the Department. South Fork Trinity River basins that have been heavily treated include Big Creek (Hayfork), Tule Creek, Rusch Creek, and Little Creek. Streams with a moderate amount of instream structures are Barker Creek, lower Dubakella Creek, upper Hayfork Creek near Wildwood, Potato Creek, Olsen Creek, upper Salt Creek and Rattlesnake Creek. A complete list of streams treated, who performed the labor, and what type of projects were carried out can be found in Tables 10-1 and 10-3.
Table 10-3.
Types of Instream Fish Habitat Improvemetn Structures Placed in South Fork Trinity
River Basin Tributaries (Flosi, 1987-1992)
Stream Name Log Weirs Boulder Digger Cover Wing Root Boulder Bank Sediment
Weirs Logs Logs Deflectors Wads Clusters Revetment Check Dams
Big Cr. X X X X X X X
Butter Cr. X
Cold Camp Cr X
Dubakella Cr X X X X
Gemmil Gl. X
Hayfork Cr. X X X X
(Upper)
Hayfork Cr. X X
(East Fork)
Little Cr. X X X X X
Madden Cr. X X
Olsen Cr. X X X X X
Philpot Cr. X X X X X X X X
Rattlesnake X X X X X
Cr
Rusch Creek X X X X X X X
Salt Cr. X X X X
South Fork X X X
(Upper)
Tule Cr. X X X X X X X
Barker Cr. X