Habitat typing reports (Frink et al., 1990) and USFS stream surveys have noted numerous water quality problems on Hayfork Creek and all of its major tributaries in Hayfork Valley. Grazing on Carr Creek, Salt Creek and its tributaries, and Hayfork Creek has caused loss of riparian vegetation and bank trampling. Cut banks may be contributing sediment which is filling in lower Salt Creek and Hayfork Creek. This sedimentation contributes to more bank cutting in these areas. As a result of bank erosion caused by grazing, fine sediment levels in lower Salt Creek and Hayfork Creek below Salt Creek are the highest in the South Fork Trinity River basin (see Chapter III).
Removal of the riparian canopy (by grazing and other means) has contributed to increased water temperatures, which exceeded 75°F in lower Hayfork Creek in June of 1989 (Frink et al., 1990). Lower Hayfork Creek maximum water temperatures exceeded 84°F in July and August of 1990, while the South Fork Trinity River just below Butter Creek attained a maximum of 78° (USFS, 1991a). Therefore, Hayfork Creek exacerbates temperature problems in the main South Fork Trinity River in some years, whereas it formerly provided a moderating influence. Water temperatures reached 81 degrees F in September 1989 in the South Fork Trinity River below Hyampom (Dale, 1990).
Fecal material from livestock can also increase biological oxygen demand (B.O.D.) "which may cause serious oxygen depletion. This is especially harmful to stream organisms (such as salmonids) that have high dissolved oxygen requirements. Temperature increases further compound this problem as higher water temperatures reduce saturation levels of dissolved oxygen in the water" (Platts, 1990). This particular problem has never been the subject of study in Hayfork Creek or its tributaries, but it is probable that livestock are contributing to water quality problems. Agricultural runoff of fertilizers and pesticides in the Hayfork Valley may also contribute to decreased water quality but again, specific problems are not documented.
Flow depletion, lack of riparian cover, and water pollution all effect the ability of Hayfork Creek and its major tributaries in Hayfork Valley to produce salmon and steelhead. The most pervasive problem in Hayfork Creek is warm water resulting from depleted flows and lack of riparian vegetation. Habitat typing surveys indicate that suitable rearing habitat for 1+ and 2+ juvenile steelhead is very limited in Hayfork Valley and lower Salt Creek (Frink et al., 1990), and in lower Big Creek, Carr Creek and Tule Creek (Plate 2). Most successful recruits into the adult steelhead population spend two to three years in freshwater (Mills and Wilson, 1991; Wilson and Mills, 1992). Juvenile steelhead can be seen in all habitat types in Hayfork Creek and in the main South Fork Trinity River in the spring before flows drop and stream temperatures increase. However, during the late summer, usable habitat is restricted to cascades, high gradient riffles, the mouths of cool tributaries, and/or deep, stratified pools where water temperature and dissolved oxygen are sufficient for survival.
High water temperatures decrease dissolved oxygen and the high BOD caused by wastes from septic systems and grazing animals exacerbate this problem. Any other organic or inorganic pollutants contributed from industrial, agricultural, or domestic sources may also be concentrated during periods of flow depletion. The cumulative effect of all these water quality problems is to increase the stress on salmonids, which in turn depresses their resistance to disease. Water quality in Hayfork Creek also becomes degraded to the point where it is a public health concern (Frink et al., 1990).
Instead of providing a moderating influence of cool water on the warm South Fork Trinity River, Hayfork Creek adds to thermal problems below Hyampom. While South Fork main stem temperatures may have been high historically (Coots measured 74° F at Salyer in 1954), adaptations of stocks to high temperatures may not allow survival when temperatures rise to the high 70's and low 80's. These elevated temperatures favor exotic species, such as green sunfish and brown bullhead, which are periodically introduced. These fish have been escaping from farm and mill ponds in Hayfork Valley since the 1950's and are presently surviving in large streams. During the recent drought, reproducing adult populations have taken up residence in pools in the lower South Fork Trinity River (Mike Dean, personal communication). Stomach contents of these warm water fish showed they had been eating small anadromous fish.
If water conservation and riparian restoration measures are employed in the Hayfork Valley, it will help remedy the serious water supply problem in the area and improve water quality for fish. Numerous sources of funding are available to private land owners to improve efficiency of water use and to prevent water pollution. Public funding sources, such as those available through the ASCS, are not available if a landowner or water user is ordered by the SWRCB, or any other regulatory agency, to change their practices. Therefore, it may be wise for ranchers and farmers to accept help in improving efficiency of water use, and to proactively abate pollution problems related to grazing, instead of waiting to take action until after complaints are lodged.
Problems related to sedimentation in the main stem of the South Fork Trinity River will persist for many years, but water quality problems and lack of flow in Hayfork Creek could be reversed in a much shorter time. If the conditions causing water temperature problems are not addressed, salmon and steelhead could be permanently lost. Conversely, addressing these water problems and issues could trigger the potentially rapid recovery of anadromous populations. Hayfork Creek could serve as the wellspring of recovery for spring chinook, fall chinook and summer steelhead, because of the deep holding pools available in Hayfork gorge just upstream of Hyampom. With cooler water in the summer, populations of steelhead juveniles could rebound to levels not seen since the 1950's.
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