Level II Stream Survey for the Timberline Express Proposal

Transcription

1 TECHNICAL MEMORANDUM th Place SE Suite 6 Bellevue WA 987 Tel: Fax: TO: FROM: CC: Bill Granger Travis Spikes Timberline Express EIS project folder DATE: October 21, 24 RE: 1. GENERAL WATERSHED CHARACTERISTICS Location: The West Fork Salmon River is located within the Mt. Hood National Forest and originates on the southwest slopes of Mt. Hood, Oregon. The West Fork Salmon River is a headwater tributary to the Salmon River. Elevation and General Gradient: The West Fork Salmon River originates at an elevation of approximately,9 feet as an ephemeral stream channel within the Timberline Special Use Permit (SUP) area. The West Fork Salmon River becomes perennial at approximately 4,9 feet in elevation as a result of three groundwater-fed tributaries that flow into the mainstem stream channel. The West Fork Salmon River flows southerly from this point for approximately three miles to its confluence with the mainstem Salmon River at approximately,6 feet. Sinuosity: The sinuosity of the surveyed reaches of West Fork Salmon River is 1.7, which is considered low according to the Rosgen classification method. Fish Populations: No fish were observed within the surveyed reaches of the West Fork Salmon River during a survey by fish biologists from Jones and Stokes who performed fish surveys concurrent with the level 2 survey (Jones and Stokes, 24). A recent snorkel survey performed by the U.S. Forest Service (USFS) in the lower reaches of the West Fork Salmon River, below the reaches surveyed in this report, observed cutthroat and rainbow trout in the main channel and tributaries to the West Fork Salmon River from River Mile. to 1.1 and again from 1. to 1.6 (USFS, 24). Barriers to Fish Passage: foot vertical falls at RM 1.1 (USFS, 24 and USFS, 1987) 2 foot vertical falls at RM 2.2 (SE Group, 24 and USFS, 1987) Culvert at Timberline Road at RM 2. (SE Group, 24 and USFS, 24) 4 foot vertical falls at RM 2.7 (SE Group, 24 and USFS, 1987) Timberline Express Proposal DEIS 1

2 2. REACH SUMMARIES Table 1 presents the major channel features and resulting Rosgen classification of each surveyed reach within the West Fork Salmon River. Figure 1 depicts the surveyed reaches. Reach Table 1 Reach Summary for the 24 Survey of the West Fork Salmon River. Survey Start (RM) Survey End (RM) Average Width (ft) Entrenchment Ratio Width to Depth Ratio Average Gradient (%) Dominant Substrate Gravel A Gravel A4a+ REACH 1 Order and Classification: Within Reach 1, the West Fork Salmon River has been classified as third order, Rosgen Type A4 stream. Frequency of Measured Units: Due to the short length of this reach, every habitat unit was measured. Access: The bottom end of Reach 1 was accessed via Snowbunny Road, off of Highway 26. Useful Information: This reach was selected through input from the Forest Service as the most likely place for fish presence due to the low gradient in topography (Saiget, Pers. Comm., June, 24). The survey started at the upstream inlet of the culvert on Snowbunny Road at RM 1.6. REACH 2 Order and Classification: Within Reach 2, the West Fork Salmon River has been classified as second/third order, Rosgen Type A4a+ stream. Frequency of Measured Units: Every fifth habitat unit was measured beginning with the fifth fast-water and fifth slow-water unit, with the exception of a.1 mile segment at elevation 4,7. Rosgen Class Access: The bottom end of Reach 2 was accessed via Snowbunny Road, off of Highway 26. The middle of Reach 2 was accessed via Timberline Road, and the top end of Reach 2 was accessed from the pumphouse at the Timberline Ski Area. Useful Information: This reach was selected through input from the Forest Service as having a reduced likelihood of containing fish due to the higher gradient as compared to reach 1(Saiget, Pers. Comm., June, 24). Timberline Express Proposal DEIS 2

3 TRIBUTARIES Several tributaries were observed during the survey of Reaches 1 and 2. Table 2 presents the data collected for all tributaries encountered. Table 2 Tributaries Observed in the 24 Survey of the West Fork Salmon River. Tributary NSO # RM Downstream Orientation Flow Contribution (%) Gradient at Mouth (%) Temperature ( C) Left Bank Left Bank Right Bank Right Bank Right Bank Right Bank Five of the tributaries observed have gradients steeper than 2 percent, indicating that fish access to habitat outside of the surveyed reaches of the West Fork Salmon River is likely blocked by a sustained gradient barrier (Washington Department of Fish and Wildlife, 2). Additional reconnaissance of these tributaries would be necessary to determine if the gradient barriers observed are sustained for 28 feet or more. No fish were observed in the vicinity of tributary 2 and it is located upstream of a 2 foot-tall natural barrier and a culvert barrier. Tributaries 1 and 2 exhibited higher stream temperatures than the mainstem of the West Fork Salmon River, which is likely do their surface water driven flow regimes and relatively low elevation. The low stream temperatures measured in tributaries through 6 are likely attributed to the groundwater-fed slope wetlands that serve as the headwaters to these tributaries in the vicinity of the pumphouse area (SE Group, 24 and Golder, 1998).. FAUNAL COMMUNITY FISH COMMUNITY No fish were observed within the surveyed reaches of the West Fork Salmon River (Jones and Stokes, 24 and USFS, 24). OTHER FAUNA During the survey, several red-legged frogs (Rana aurora) were observed within Reach 2. Also, an American dipper (Cinclus mexicanus) was observed within Reach 2. Evidence of deer and elk was observed through numerous game trail crossings on the stream banks within both surveyed reaches. Timberline Express Proposal DEIS

4 4. IN-CHANNEL HABITAT TEMPERATURE Stream temperature was recorded at the downstream end of each reach. Additional temperature readings were recorded within the mouth of every tributary with adequate flow and in the mainstem of the West Fork Salmon River upstream of the mixing zone with each tributary. The average daytime temperature in both surveyed reaches was.2 degrees Celsius. LARGE WOODY DEBRIS Large woody debris (LWD) was divided into categories in Table according to the survey protocols outlines in the Stream Inventory Handbook Level I and II (USFS, Pacific Northwest Region, 24). Table Large Woody Debris Classification for Westside Forests. Size Diameter Length Small inches 2X Bankfull width Medium 24-6 inches 2X Bankfull width Large >6 inches 2X Bankfull width The following table presents the observed LWD abundance by reach and the relevant Mt. Hood National Forest Land and Resource Management Plan (LRMP) standards. Based on the results of the survey, Reaches 1 and 2 are below the LRMP standards for medium and large LWD density (Table 4). Table 4 Reach Summary for Observed Large Woody Debris Abundance in the Surveyed Reaches of the West Fork Salmon River. Reach Length Number of Pieces Density (pieces/ mile) Small Medium Large Total Small Medium Large Total LRMP Density Standard for M & L (pi/mi) LARGE WOODY DEBRIS JAMS A total of LWD jams were identified during the survey of the West Fork Salmon River. Reach 1 contains two LWD jams composed of small LWD pieces, and Reach 2 contains one LWD jam composed also of small LWD pieces. No medium or large LWD jams were observed during the survey. Timberline Express Proposal DEIS 4

5 POOLS According to the 24 Level II survey protocol, a pool is defined as a habitat unit that has: little or no surface gradient, a hydraulic control that spans the channel, and a residual pool depth. The following table presents summaries of the pool characteristics by reach (Table ). Table Reach Summary for Observed Pools in the Surveyed Reaches of the West Fork Salmon River. Reach Length Average Bankfull Width (ft) Total Pools Pools per Mile LRMP Density Standard for Pools (pool/mi) Pool quality throughout the surveyed reaches was poor. The average pool depth was approximately one foot and pool length was between one to two times the wetted width. Many of the observed pools were created by debris jams that could potentially be washed out during high flow events. Due to the high gradient of the surveyed reaches, a majority of the pools measured were subsets of larger step-pool habitats, including many pools that were not long enough to characterize as separate habitat units. Pebble Counts Pebble counts were performed in the upper and lower thirds of each reach following Wolman survey protocol. The following table presents summaries of the pebble counts for each reach (see Table 6). Table 6 Summary of Pebble Counts Performed in each Reach Substrate Type (Size Range) Sand, Clay, Silt (<2mm) Gravel (2-64mm) Cobble (64-26mm) Boulder (26-496mm) Lower Count (% of total) Reach 1 Reach 2 Upper Count (% of total) Lower Count (% of total) Upper Count (% of total) 7 (.9) 2 (2.1) 1 (.7) (.) 4 (44.1) 66 (61.1) 61 (6.4) 4 (4.) 1 (12.1) 9 (8.9) 2 (2.) 4 (.7) Bedrock Number of Transects Timberline Express Proposal DEIS

6 . RIPARIAN HABITAT The plant associations in the riparian zones adjacent to the measured units in reaches 1 and 2 where determined using the methodology in Plant Association and Management Guide for the Mountain Hemlock Zone (USDA, 1997) and Riparian Ecological Types Gifford Pinchot and Mt. Hood National Forests and the Colombia River Gorge National Scenic Area (USDA1996). Descriptions from the plant associations observed during the survey have been excerpted from these guides. Please refer to the guides for more detailed descriptions of the plant associations included below. The vegetation communities observed during this stream survey where broken into three distinct zones according to the standard survey procedures followed by the Mount Hood National Forest. Zone 1 is defined as the frequent flood zone, which is typically the area below the bank full elevation (hereafter referred to as Bank Full Zone). Zone 2 is defined as the flood prone area, which is flooded much less frequently (hereafter referred to as Floodprone Zone). The Upslope vegetation zone is the land area starting at the outer edge of Zone 2 and extending away from the stream to a combined distance of 1 horizontal feet of the stream channel (including Zone 1, Zone 2, and the Upslope zone). REACH 1 The dominant plant association observed in the Upland Zone in the measured units of Reach 1 was the Mountain Hemlock/Big Huckleberry/Beargrass association. The average canopy cover attributed by Mountain Hemlock in these units was approximately percent. This association occurs in dry, cold forested environments. Soil is often effectively dry, and soil nutrients may be limited due to slow decomposition of organic matter. The most common plant association in the Floodprone Zone within Reach 1 was the Alaska Huckleberry/Ovalleaf Huckleberry association. This plant association occurs in cool, moist riparian fringe sites with relatively productive, well-drained soils. Inundation is likely to be infrequent and low in intensity. Fool s huckleberry (Menziesia ferruginea), Stink currant (Ribes bracteosum), and salmonberry (Rubus spectabilis) is sometimes found in this association. The forb species typically observed within this plant association include Arrowleaf groundsel (Senecio triangularis), Bunchberry dogwood (Cornus canadensis), Claspleaf twistedstalk (Streptopus amplexifolius), and Vanilla leaf (Achlys triphylla). No vegetation was growing in the Bank Full Zone in most (7 percent) of the measured units in Reach 1. When vegetation was present in the Bank Full Zone, it was typically dominated by moss species and Marsh marigold. REACH 2 Similar to Reach 1, the dominant plant association observed in the Upland Zone in the measured units of Reach 2 was the Mountain Hemlock/Big Huckleberry/Beargrass association. The average canopy cover attributed by Mountain Hemlock in these units was approximately 24 percent. Approximately percent of the measured units in Reach 2 had an upslope plant association of Pacific silver fir/big huckleberry/beargrass. The preliminary difference between the two observed upslope plant associations in that the overstory and regenerating sapling species is Pacific silver fir. The shrub and herb layer is very similar in both associations observed. Timberline Express Proposal DEIS 6

7 The most common plant association in the Floodprone Zone within Reach 2 was the Alaska Huckleberry/Ovalleaf Huckleberry association. This association was very similar to the association observed in Reach 1, but the extent of the Floodprone zone was generally less and the transition to the adjacent uplands was more abrupt in Reach 2. Moss was most commonly observed growing in the Bank Full Zone in the measured units in Reach 2. The Bank Full Zone was in a non-vegetated state in approximately 4 percent of the measured units. 6. MANAGEMENT ACTIVITIES/ IMPACTS ROADS Timberline Road intersects the West Fork Salmon River at approximately RM 2.. Large quantities of road sand and gravel were observed in the stream and on adjacent banks downslope of the road, with large accumulations below the 2 foot waterfall at RM 2.2. No damage or excessive erosion was observed in the culverts under Timberline Road and Snowbunny Road. These two culvert crossings were classified as full barriers to fish passage in the 1987 survey of these reaches. However, only the paired culverts under Timberline Road were classified as barriers to fish passage in the 24 survey performed by the USFS (USFS, 1987 and USFS, 24). BANK INSTABILITY Very few areas of bank instability were observed during the stream survey, as compared to the overall length of the two reaches surveyed. Table 7 presents a summary of the unstable banks observed. The left and right bank headings denote the downstream orientation of observed bank instability. Reach River Mile Table 7 Bank Instability Summary for the Surveyed Reaches of the West Fork Salmon River. Unstable Banks (linear ft) Left Bank Right Bank Total Notes Most areas are game trail crossings Large slope failure observed approximately, ft. upstream of Timberline Rd. Timberline Express Proposal DEIS 7

8 References Golder Associates Inc Timberline Ski Area, Section 41 Certification, Summary Report. January, Redmond, WA Jones and Stokes. 24. Timberline Express Fisheries Technical Report West Fork Salmon River. Portland, OR SE GROUP. 24a. Wetland and Stream Survey for the Timberline Express Proposal. Bellevue, WA. Saiget, Dave. June, 24. U. S. Forest Service, Mt. Hood National Forest, Zigzag Ranger District, Fisheries Biologist. Discussion stream reaches in the West Fork Salmon River most likely to contain fish or fish habitat during meeting at the Zigzag Ranger District office. USFS West Fork Salmon River Survey Summary. Mt. Hood National Forest, Zigzag Ranger District. USFS The 1996 Stream Survey Still Creek. Mt. Hood National Forest, Zigzag Ranger District. USFS. 24. West Fork Salmon River Fish Survey. July 12 21, 24. Mt. Hood National Forest. Zigzag Ranger District. USFS. 24. Stream Inventory Handbook Level I and II. Version 2.4. Pacific Northwest Region. Washington Department of Fish and Wildlife. 2. Fish Passage and Surface Water Diversion Screening Assessment and Prioritization Manual. Timberline Express Proposal DEIS 8

9 2 Tributary 6 49 Tributary Tributary 1 Tributary 47 Falls - 4' 48 " 48 REACH 2 Tributary 2 ( Natural Landslide 47 on RL bank 4 Depisitional Reach ' Side Channel Falls - 2' T " Tributary REACH T 42 Contour interval: Feet Figure 1 Level II Survey Field Map for the West Fork Salmon River 8/16/24 :9:9 PM Stream - Perennial Reach 1 " Stream - Ephemeral Wetland T Stream - Intermittent USFS Stream Data 4 2 Reach 2 Study Area Boundary 1, Feet Falls Culvert Pebble Count