Note: Nice Chapter 3 from the Taylor Fork FEIS (with both affected environment and environmental consequences combined) for three water and fish issues. It is easy to read and understand with appropriate supporting information in the project file.
FEIS Chapter 3 – Affected Environment and Environmental Consequences
Issues 1 through 3
Issue 1 and Issue 2:
Fisheries -
Westslope Cutthroat Trout and
Salmonid Spawning and Rearing Areas
The cumulative effects of existing roads, past timber harvest and the proposed activities in the Buck Creek drainage could have an effect on westslope cutthroat trout by potentially increasing sediment delivery to the stream course. Westslope cutthroat trout have been petitioned to be listed as a Threatened species under the Endangered Species Act by the USFWS. The Buck Creek population has been determined to represent a hybridized population of at least 90 percent genetic purity. The Taylor Fork population is more heavily hybridized with rainbow and Yellowstone cutthroat trout and is classified as less than 90% genetically pure.
Changes between the draft and final EIS
Several comments to the draft EIS fisheries analysis requested information on the genetic purity of the westslope cutthroat trout populations found in Taylor Fork and Buck Creek drainages. This information is provided describing the genetic purity sampling methods and findings performed in 1989 and 1994 within the analysis area. In addition, sediment delivery rates have been adjusted and effects analyses for water quality and fisheries have been updated to reflect road obliteration work that will occur in the summer of 1999.
a. Affected Environment
Taylor Creek
Taylor Creek is a fourth order tributary which enters the Gallatin River about 3 miles downstream of the Yellowstone National Park boundary on US highway 191. Several large third order tributaries to Taylor Creek including; Wapiti, Cache, and Lightning Creek drain this high elevation 160 square kilometer basin. Highly erosive and naturally unstable soils derived from sedimentary rocks make up the primary geology in the basin. Historic and current land uses such as timber harvest, tie driving, splash damming, livestock grazing, road construction and channelization, have all resulted in accelerated sediment delivery rates and reduced stream channel stability within the Taylor Fork drainage.
In the mainstem Taylor Fork, stream channel stability was drastically influenced by historic splash damming and tie drives. Channel instabilities remain noticeable for some distance below the splash dam located in T9S-R3E-SEC 9. Stream channel cross-sectional profiles reflect an over widened and braided character within this reach. Ireland (1993) as part of the investigation of seasonal distribution and habitat usage of westslope cutthroat within the Taylor Fork drainage described this stream section as having a width depth ratio of about 24, a high level of surface fines, and high degree of bank instability.
Ireland (1993) provides a detailed description of several habitat variables within 4 reaches of Taylor Creek including; percent surface fines, maximum pool depths and bank stability. Surface fines were estimated to be about 26% in the lower middle portion of the mainstem and only about 4% in the upper portion of the Taylor Fork. Sediment core samples taken from the mainstem Taylor Fork at the very lower portion of the drainage indicated that sediment levels were moderately high (average percent fine sediment less than 6.3 mm was 28%). Stream channel instability was evident in all Taylor Fork reaches and Ireland (1993) attributed the instability to operation of the splash dam, grazing and roads. Pool quality and quantity was low in all reaches.
Westslope cutthroat trout of slightly less than 90 percent genetic purity are found throughout the Taylor Fork drainage (Table III-1). The sample taken in T9S-R3E-Sec. 20, during 1989 of 93 % genetic purity was taken in upper Taylor Creek upstream of the Lightning Creek confluence, subsequent sampling in 1993 immediately upstream of this location resulted in a sample of reduced genetic purity indicating possible further hybridization of this upper Taylor Fork population. No fish have been documented as present above Taylor Falls upstream of these sample sites. As rainbow trout were stocked within Taylor Fork Creek up to the early 1990s and as the drainage is not isolated from the Gallatin River, the chances of the mainstem Taylor Fork Creek containing westslope cutthroat trout population of greater than 90 percent genetic purity is extremely small.
**Table III-1. Genetic sampling of westslope cutthroat trout within the Taylor Fork drainage.
Date / Location / Sample Size / Genetic Purity WSC1989 Taylor / T9S-R3E-SEC 20 / 25 / 93%
1993 Taylor / T9S-R3E-SEC19 / 13 / 84%
1993 Tumbledown / T9S-R3E-SEC19 / 3 / 84%
1989 Cache / T9S-R3E-SEC 4 / 25 / 87%
1989 Dead Horse / T9S-R3E-SEC 3 / 25 / 85%
1992 Wapiti Ck. / T10S-R3E-SEC 3&10 / 15 / 57%
Distributions and habitat use information indicated that the mainstem Taylor Fork supported very low densities of cutthroat (0.3-2 fish/100 sq meter in summer, 0.4-4 fish/100 sq. meter in winter). Several reasons for the very low cutthroat densities were identified and include: 1) influence of elevation and stream order; 2) competition with introduced species; 3) proximity to spawning areas; and 4) high angling mortality. Poor quality pool environments have also likely contributed to the low trout densities. It is also expected that rainbow trout from the Gallatin River utilize the lower portion of Taylor Fork for spawning.
Magee (1993) completed an in depth survey of westslope cutthroat spawning habitat within the Taylor Fork drainage. He was unable to locate cutthroat redds within the mainstem Taylor Fork because of turbidity associated with high flows at the time of sampling. Magee (1993) reported fine sediment (< 6.3 mm diameter) levels to average about 39 % within spawning substrates of the Taylor Fork drainage which is higher than the optimum level of less than 25% fines associated with high quality cutthroat spawning habitat.
Wapiti Creek was intensively inventoried by both Ireland (1993) and Magee (1993). Wapiti Creek was also addressed in Snyder's 1978 watershed assessment and the lower stream section was rated as good from a stability standpoint. Ireland (1993) surveyed three reaches of Wapiti Creek and found substantial differences between the reaches for certain habitat attributes. The lower portion of the stream had a high percentage of riffle habitat and low percentage of surface fines. Channel instability was not highlighted as a significant problem. Substrate core samples taken from the lower stream reflected a clean substrate (21% fines). Habitat use by adult trout in lower Wapiti Creek was very low and rainbow trout were dominant.
Magee (1993) found low densities of westslope cutthroat and other trout redds in lower Wapiti Creek. Lack of spawning habitat would be consistent with the nature of the channel in this stream section. The mid section of Wapiti Creek had a higher gradient (2.5%) that is consistent with a B2 channel type with habitat associated with step pools and fast water runs. Cutthroat trout densities observed during summer months were higher than those observed in the lower Wapiti Creek section. Percent surface fines were approximately three times higher in the middle section as compared to the lower area of the stream (Ireland, 1993). Magee (1993) observed lower densities of cutthroat trout redds within this section, which would be consistent with the habitat capability.
The upper most section of Wapiti Creek supports the highest quality trout habitat characterized by a sinuous, slightly confined channel with high pool to riffle ratio, gravel size substrate and varying amounts of surface fines (ave. 10% surface fines) (Ireland, 1993). When compared to densities of the lower portions of Wapiti Creek, this upper area supported a ten fold higher density of cutthroat both in summer and winter, (18-23 fish/100 meters during summer; 29-33 fish/100 meters during winter).
Meadow Creek
Rainbow trout were stocked in Albino Lake in the Meadow Creek drainage during the 1950s and have been reported to be hybridized with Yellowstone cutthroat trout, which maintain a self supporting population. It is likely this hybridized non native fish population drifts downstream throughout the Meadow Creek drainage. As Meadow Creek is a very low gradient stream channel with no passage barrier isolating it from Taylor Creek it is very unlikely westslope cutthroat trout would be present in Meadow Creek.
Habitat conditions reflect moderately high sediment delivery. Channel instability along Meadow Creek is evident at numerous locations and fine sediment levels are high. The high sediment levels can be attributed to the naturally erosive character of the watershed and to past and present livestock and wildlife use. Meadow Creek is classified as a Class C stream under Forest Plan implementation guidelines as the fishery is of limited significance and provides a dispersed fishing opportunity with few fish over 10 inches in length.
Cache Creek
Cache Creek covers an area of 10.0 sq. miles in the northwest end of the Taylor Fork drainage. Snyder (1978) commented that Cache Creek drainage was a mixture of sedimentary formations and that heavy suspended sediment loads were a consequence of the sedimentary geology aggravated by timber harvest and grazing.
Ireland (1993) surveyed three reaches of Cache Creek and found substantial differences between the reaches for certain habitat attributes. The lower and upper portions of Cache Creek were characterized by sinuous, slightly confined channels with substantial numbers of pools and high level of surface fines. The middle reach had a substantially higher channel gradient, with habitat features dominated by step pools and runs. Substrate surface fines were also high in the higher gradient stream section. Magee (1993) collected substrate core samples from cutthroat redds and found high fine sediment levels (ave. 40% fines less than 6.3mm).
Substrate core samples taken in 1990 just above the confluence with the mainstem Taylor Fork had levels of fine sediment that were substantially lower (ave. 16% less that 6.3mm). The difference in fine sediment conditions between the two sampling periods and locations may have been an artifact of sampling protocol. Magee's samples came from actual redds and are felt to better represent substrate conditions of concern. Land uses associated with grazing and timber harvest were identified as factors contributing to negative conditions in Cache Creek by Snyder (1978), Ireland (1993) and Magee (1993). Alteration of the timing and intensity of spring runoff in combination with the historic and current effects of the Cache/Eldridge grazing allotment has likely led to alteration of stream channel form and function. Channel overwidening, downcutting, altered riparian vegetation, and a lowering in the water table is evident in the upper reaches of the meadow section on Cache Creek.
Cutthroat trout use of Cache Creek, both from the perspective of population density and number of redds, was higher than in any other area of the Taylor Fork drainage. Ireland's (1993) population density information indicated that Cache Creek, especially the upper portion, supported relatively high numbers (22 fish/100 meters in summer; 33 fish/100 meters in winter). Magee (1993) noted that Cache Creek had the highest percentage (70%) of cutthroat trout redds located within the Taylor Fork drainage. As a result of the currently elevated sediment levels within Cache Creek, egg survival was projected to be very low (Magee, 1993).
Buck Creek
Buck Creek is a third order tributary the Gallatin River entering about 10 miles downstream of the Yellowstone National Park boundary on US Highway 191. Buck Creek covers a 24 sq. mile watershed. Historic logging associated with the rail road tie cutting occurred in the early 1900's. The remains of two splash dams still exist in sections 13 and 14 on the main stem of Buck Creek. Recent road construction and timber harvest, within the last 10 to 15 years, has resulted in a cumulative sediment delivery estimate of about 600% over natural. Buck Creek supports a westslope cutthroat trout population of 97% genetic purity. A sample of 26 trout was collected in T8S-R3E-Sec 15 in 1994 to determine genetic composition.
Stream substrate sediment core samples taken in July of 1996, reflected moderately high fine sediment levels. Cores taken from actual redds (two sites) had an average of 19% fines. Fine sediment levels in undisturbed spawning sites averaged 30.5%, which is a level consistent with sediment model/substrate relationships that has been verified through monitoring.
Based on fish habitat surveys completed in 1996 it is evident that main stem Buck Creek has been significantly influenced by past timber harvest activities (e.g. splash damming, riparian harvest, road construction and harvest outside of riparian areas). The lower three miles of Buck Creek have been heavily influenced by historical splash damming. The scouring action of tie drives has resulted in extensive stream bed and bank scour in many locations. The lower portion of Buck Creek is dominated by fast water habitat types such as high gradient riffles and runs with little habitat complexity. Pool habitats are very limited and those that do exist are small and have limited cover and complexity.
The middle section of Buck Creek upstream of the splash dam supports higher quality habitat and moderate numbers of slightly hybridized westslope cutthroat trout. Pool habitats were more abundant and fish were observed in most pools. Substrate conditions reflected moderately high levels of fine sediment. Streambank instability was evident throughout most of the middle stream section.
The upper most section of Buck Creek was substantially higher in stream gradient. Fast water habitats dominated and pool environments were limited to smaller plunge pools and pocket water. Increased fine sediment within the channel was also observed in this upper stream channel. Fish were observed in three tributaries to Buck Creek. The most significant of these tributaries entered Buck Creek in section 13. This tributary supported a substantial population of westslope cutthroat trout and had habitat that was in good condition.
Other fish species present in Buck Creek include rainbow trout, which inhabit the lower two miles of stream channel downstream of an old splash dam that prevents upstream migration. Also, Lizard Lakes in the upper end of the drainage supports a self sustaining stocked Yellowstone cutthroat trout population.
b. Direct and Indirect Effects
The potential effects of the proposed timber sale are of two types: direct and indirect effects. The direct effects would be those effects, which would result in the direct mortality of fish or destruction of fish habitat, such as a fuel spill from logging equipment traveling to and from the harvest sites. Indirect effects would be effects resulting in changes to fish habitat as a result to changes in the aquatic environment such as the potential for altering the rate in which sediment or woody debris enters the stream channel.
As this proposal contains no riparian timber harvest those habitat attributes related to riparian vegetation need not be analyzed such as; large woody debris recruitment to stream channels, alteration of water temperatures through reduced shading, and changes in streambank stability from near channel activities.
Sediment delivery rates to fish bearing streams and the increased risk of a fuel spill in the Gallatin River associated with log hauling intensities was used to determine the potential effects to fisheries. The potential of additional sediment delivery to salmonid spawning and rearing areas is the primary issue of concern relative to effects on fish habitat from this proposal and will be used to make comparisons between the alternatives. Elevated levels of fine sediment (material < 6.3 mm in diameter) have been shown to affect salmonid habitat used for spawning, rearing and overwintering (Chapman and McLeod, 1987). Pollution intolerant macroinvertebrate abundance, survival of embryos to emergence, pool volume, and quantity of overwintering habitat for salmonids are correlated with the level of fine sediment in streams (Chapman and McLeod, 1987).
Existing and potential sediment yields including reductions from road rehabilitation were calculated by the Gallatin National Forest hydrologist (Story 1999) for all alternatives using a modification of the R1/R4 sediment model (Cline et al. 1981). The effects of additional delivery of fine sediment on fish habitat quality will be dependent on precipitation, streamflow, how quickly exposed soil is stabilized, and how the sediment is delivered to and routed within the stream during harvest activities. The effects of additional sediment delivery from harvest activities on fish spawning and rearing habitat was estimated for all alternatives using a modification of the Fish/Sed model which estimates the change in substrate composition that results from changes in sediment delivery rates (Stowell et al. 1983). This modification more accurately reflects sediment routing relationships of geologies found on the GNF. The coefficient of 0.24 best reflects this relationship from an annual perspective.