Watershed/Aquatic Habitat Draft Assessment

Transcription

1 : Phase I Watershed/Aquatic Habitat Draft Assessment Arizona Department of Game & Fish Canyon Creek, Arizona March 2008

2 : Phase I Watershed/Aquatic Habitat Draft Assessment Arizona Department of Game & Fish Canyon Creek, Arizona Submitted to: Arizona Department of Game & Fish 2221 W. Greenway Road Phoenix, AZ Prepared by: Natural Channel Design, Inc. 206 S. Elden St March 2008

3 Table of Contents PROJECT DESCRIPTION... 1 PROJECT PURPOSE... 1 PROJECT LOCATION... 1 SITE DESCRIPTION... 3 SURVEY PROTOCOL... 3 EXISTING CONDITIONS... 4 VEGETATION... 4 WATER QUALITY... 6 FISHERIES... 7 HYDROLOGY... 7 GEOMORPHOLOGY FISH HABITAT ASSESSMENT RECOMMENDATIONS MONITORING PRESCRIPTIONS FOR POTENTIAL IMPROVEMENTS Root wad Log overhang Cross-over log Loose crossed logs Log barb Rock barb Boulder clusters Mini weir Pool excavation Bank sloping Brush revetment Willow pole planting POTENTIAL AREAS OF ENHANCEMENT LITERATURE CITED APPENDIX A HABITAT ENHANCEMENT STRUCTURES DETAIL SHEETS i

4 List of Figures Figure 1. Project location map of Canyon Creek... 2 Figure 2. Typical vegetation overstory from springbox to Hatchery Bridge Figure 3. Typical vegetation overstory between Hatchery Bridge and OW Bridge... 5 Figure 4. Typical vegetation overstory below OW bridge Figure 5. Canyon Creek project area watershed delineations Figure 6. Geomorphic survey locations in Canyon Creek Figure 7. Aggraded pools upstream of Hatchery Figure 8. Typical fish habitat below OW Bridge Figure 9. Watercress patches in Canyon Creek Figure 10. Fallen log creating pool habitat Figure 11. Remains of engineered log structure Figure 12. Location of sites for habitat improvement in Canyon Creek Figure 13. Locations of proposed habitat improvements in Canyon Creek List of Tables Table 1 Estimated discharges using NRCS regional hydrology... 9 Table 2 Estimated discharge using NFF V Table 3. Channel dimensions for survey sites in Canyon Creek Table 4. Length of stream for pool, riffle and run habitats Table 5. Location of proposed improvement sites with types and number of prescriptions ii

5 PROJECT DESCRIPTION Canyon Creek supports an important trout fishery managed by Arizona Game and Fish Department (AGFD). The stream is managed as both a natural recruitment brown trout (Salmo trutta) and stocked rainbow trout (Onchorhynchus mykiss) fishery. In recent years, the stream and fishery have suffered due to damage to the watershed and riparian vegetation from the Rodeo-Chediski Wildfire and over browsing by elk and cattle. AGFD wishes to enhance the fishery by improving available habitat in the stream. The Canyon Creek Watershed Project is a two-phase project. The first phase is to assess current stream morphology and habitat conditions and provide a set of enhancement alternatives for the project reach. The second phase is to design and implement the enhancements. All designs are intended to improve stream function and stability as well as habitat quality. This report addresses Phase One. PROJECT PURPOSE Arizona Game and Fish Department wishes to assess the current morphological and habitat conditions of the stream, as well as current biological data, then develop an enhancement plan that will prioritize areas with the greatest enhancement potential. Enhancements will improve geomorphic stability of the stream as well as improve riparian habitat and stream habitat conditions for trout and native fish and increase riparian vegetative cover. The purpose of Phase One of this project is to provide a geomorphic assessment of Canyon Creek, describe the habitat conditions and trends, and describe potential (or probable) stable state and departure by stream reach. Design and implementation of habitat improvements will begin once the assessment and recommendations have been approved by AGFD. PROJECT LOCATION Canyon Creek Watershed Project is located east of Payson, Arizona, in Gila County, below the Mogollon Rim. It is in all or portions of Sections 35-36, T11N, R14E; Sections 21, 22, 27, 34, T10.5N, R14E; and Section 3, T10N, R14E. The project area is approximately 5 miles long beginning above the Hatchery Bridge and ending at the confluence of Valentine Creek. The project site is located entirely on Tonto National Forest Land. Figure 1 shows the approximate location of the project site. Natural Channel Design, Inc. 1 March 2008

6 Approximate Project Site location Figure 1. Project location map of Canyon Creek. The red line indicates the approximate portion of Canyon Creek within the project area. Natural Channel Design, Inc. 2 March 2008

7 SITE DESCRIPTION The watershed of Canyon Creek area lies immediately below the Mogollon Rim. It flows from the northwest to southeast across central Arizona. The project area is located in the headwaters of the Salt River. It is located approximately 40 miles east of Payson, Arizona and lies completely within the boundaries of the Tonto National Forest. The project area ranges from 6700 to 6200 feet in elevation. The project area is approximately 5 miles long beginning above the Hatchery Bridge and ending at the confluence of Valentine Creek. The stream flow originates in a series of springs which are mostly diverted for use in the hatchery. Once the hatchery returns the water to the stream (upstream of the hatchery bridge) the stream has a fairly stable baseflow. A small portion of the flow is diverted to the OW ranch at a point just downstream of the hatchery bridge. Downstream of the OW bridge there are several tributaries which add considerable drainage area to the stream but little base flow. The entire watershed has been severely impacted by the Rodeo-Chediski Fire that took place in Most of the hillsides are still bare of mature trees and only covered in grasses, shrubs, and locust. The fire also damaged or killed many mature cottonwoods and several Ponderosa pine trees near the stream. Fencing to exclude livestock surrounds the project area. The fence is mostly intact in upper portions of the project area. There are several breaks in the livestock fence in the lower reaches of the stream near Valentine Wash. However, livestock use appeared limited in these areas during our site visits during the fall of Elk fencing has been constructed around two major portions of the stream downstream of the OW bridge. While there was evidence of elk use within the exclosures,, the fences appear to be generally effective at protecting the vegetation from unsustainable browsing. SURVEY PROTOCOL Due to the diverse characteristics and length of the stream segment within the project area, an assessment walk was the most efficient way to analyze the individual reaches. During the site walk, data was collected in order to evaluate stream hydrology, geomorphology, vegetation, and aquatic conditions. The entire length of the stream in the project area was walked and visually inspected; areas with good habitat and areas with high potential for enhancement were marked with a GPS unit and access routes were identified. During the assessment walk, photos were also taken to document certain stream information. Photographs recorded: Functioning habitat, Natural structures that may be mimicked in enhancement work, Areas that need enhancement, Permanent landmarks, such as waterfalls or bedrock structures Reference areas and habitat types. Several long-term monumented cross sections have been established in Canyon Creek and previously surveyed by USFS personnel. Additionally, a cross section and profile were measured in a previously unstudied reach that also has potential for enhancement. Cross-sections reveal morphology characteristics of the stream including floodplain height and width, bankfull stage, and thalweg depth. Stream profiles provide information about the slope of the reach, including the number and spacing of channel bedforms. This survey data was used to understand channel change over time and to establish reference conditions for assessing current conditions. Natural Channel Design, Inc. 3 March 2008

8 The quality of fish habitat was visually assessed during the survey. The abundance of pool habitat, fish cover types, substrate types and activity of fish spotted in stream were documented. Access to the stream for anglers and heavy equipment, as well as proximity of suitable materials for stream improvements, were also noted. Water quality parameters related to habitat quality were assessed from existing AGFD studies. Habitat suitability was based on values from Raleigh et al. (1986). Additionally, existing data on fish and invertebrate community compositions, abundance, densities, distributions, and habitat preferences were reviewed. Recommendations for habitat improvement are based upon the need for habitat improvement in conjunction with accessibility and suitability for specific treatments and practices. Site visits were conducted during late October 2007 and early December The October visit entailed a GPS and visual survey of the entire stream from the springs through the canyon reach below Valentine Wash. Locations of cut banks, pools, functioning habitat, fences and general vegetation condition were made during this visit. During the December visit, cross section and longitudinal profile data was collected in cooperation with U. S. Forest Service and AGFD personnel. Specific points for enhancement were identified, located by GPS, and prescriptions for enhancement were made. EXISTING CONDITIONS Current conditions and trends were assessed through a review of existing reports as well as site visits to the stream. VEGETATION A detailed GIS map of vegetation types and distribution will be a future product of this project. However, detailed understanding of vegetation distribution is not necessary for planning for aquatic habitat enhancement. This report provides a coarser, visual assessment of riparian vegetation. The watershed of Canyon Creek is generally Ponderosa Pine forest. However, the forest was heavily burned by wildfire in Pioneer vegetation of grasses and locust are the current ground cover on the hillslopes. Large portions of the riparian zone were also burned during the fire resulting in the loss of many mature cottonwood trees. Currently there is evidence of regeneration of cottonwood and willow saplings along the stream corridor. However, regeneration is unevenly distributed. Vegetation along the stream can be characterized by three general reaches of stream: Hatchery outlet to the Hatchery Bridge, Hatchery Bridge to OW Bridge, and OW Bridge to Valentine Canyon. Hatchery Outlet to Hatchery Bridge This short reach consists of mature evergreen and deciduous trees that form a dense canopy over the stream (Figure 2). This reach escaped fire damage and remains a high quality riparian habitat. Immediately upstream of this reach the riparian area was wiped out by the fire and is recovering with early successional grasses and shrubs. Natural Channel Design, Inc. 4 March 2008

9 Figure 2. Typical vegetation overstory from springbox to Hatchery Bridge. Hatchery Bridge to OW Bridge- The hill slopes around this reach were burned, however it appears that the fire did not affect the riparian zone. Willows are well established along the banks with occasional mature cottonwoods, ashes and other trees (Fig. 3). There is some evidence of elk browsing in this reach, however there is regeneration within the reach and browsing rates appear sustainable. Figure 3. Typical vegetation overstory between Hatchery Bridge and OW Bridge. Natural Channel Design, Inc. 5 March 2008

10 OW Bridge to Valentine Canyon - The vegetation in this reach has been impacted by both fire and grazing (Fig. 4). The fire killed many mature cottonwood trees and likely burned many of the willows as well. Recovery of the vegetation appears dependent on control of ellk and livestock grazing. Two fenced elk exclosures have been constructed. While the exclosures do have some evidence of grazing within, they appear to have had a positive influence on vegetation recovery. Visual inspection indicated that willows and sedges are far more prevalent within the exclosures than out. Young cottonwoods are also more prevalent within the exclosure. Outside the exclosures, the vegetation is mostly grasses and mature pine trees. Mature willows and cottonwoods are scattered outside of the exclosures but there is little evidence of successful reproduction. Any shoots that were noted had been heavily grazed. Figure 4. Typical vegetation overstory below OW bridge. WATER QUALITY Annual reports compiled by the AZGFD in 2003 through 2006 collected and analyzed water temperature, ph, and conductivity as a component of fisheries surveys along the stream. The period of record for water quality data is insufficient to determine any temporal trends other than the observation of a general decrease in ph from 2005 to Both ph and conductivity increased slightly at downstream sites compared to upstream sites. However, these parameters are in an acceptable range to support trout and native fish. Water temperature is a larger concern. Stream temperatures warm rapidly through the project site. Data from the lower end of the project site indicate that optimum temperatures for Brown trout (22.2 C) were exceeded for several months in 2005 with a maximum temperature of 28 C. Temperatures in the mid portion of the project were cooler and only exceeded optimum temperatures for several weeks during July The most upstream portion of the project area Natural Channel Design, Inc. 6 March 2008

11 never exceeded optimum temperatures. Temperatures were somewhat cooler during 2005 compared to 2004 suggesting that riparian vegetation and shade may be improving (Gill 2006a). Early reports using macroinvertebrates as indicators of water quality noted the presence of several sediment tolerant species suggesting sediment impairment (Mangum 1991). However, most invertebrate taxa and other water quality parameters indicate that the stream was in a healthy, functioning condition. More recent sampling indicates that sediment tolerant taxa are still present in the stream (Vincent 1998, 2001). Visual assessment of the site suggests there is little evidence for sediment impairment of the stream and the presence of sediment tolerant taxa may be more reflective of the regional invertebrate species pool rather than poor conditions in Canyon Creek. Overall invertebrate densities and abundances indicate a productive food resource for fish populations. FISHERIES The fish community of Canyon Creek consists of Rainbow trout (Onchorhynchus mykiss), Brown Trout (Salmo trutta), Speckled dace (Rhynichthys osculus), and Desert sucker (Catostomus clarki). Trout populations have been managed for recreational fishing. Rainbow trout were originally managed as a put and take fishery by stocking catchable sized fish with brown trout managed by stocking small fish and growing them out in the stream. After the fire, the area was closed and fishing pressure decreased, but has recently started to increase again. Recovery of fish populations since the fire has been uneven. Overall, trout populations are near pre-fire conditions. However, Brown trout levels are only 48% of pre-fire conditions while Rainbow trout nearly double compared to pre-fire conditions (Gill 2006a). Large adult trout of both species prefer pool habitat over riffle habitat. However, most trout in the stream during 2006 were smaller and found in riffle habitats. Native fish also exhibit habitat preferences. Desert sucker prefer pool and run habitats and dace utilize riffles and runs. The 2006 survey found that most Brown trout were concentrated above OW Bridge, presumably due to better habitat conditions and cooler temperatures, while Rainbow trout were more evenly distributed through the project reach. There was evidence of successful spawning by both trout species during the winter period. However, previous redd count surveys suggest that availability of spawning substrate may limit the number and extent of redds throughout the project reach (Gill, 2006b). This observation is consistent with repeated pebble counts that indicate that the substrate has coarsened as the stream recovers from the effects of the fire. HYDROLOGY Canyon Creek is an ungaged tributary of the Salt River. High flows through the project area are created by both snowmelt and summer monsoon events. Ground cover in the watershed is recovering from the effects of the Rodeo Chediski fire and runoff patterns are probably at or near pre-fire condition (Grant Loomis, USFS, pers comm.) Lack of stream gage data requires that flood discharges be modeled. Two flood frequency models were utilized for this analysis. The National Flood Frequency Program (NFF v3.2; Ries and Crouse, 2002) and a regional hydrology method (NRCS, 1972) were both utilized for comparison purposes. The models rely on the correlation between gage data within the region. The NFF model uses watershed area and elevation parameters, while the regional hydrology method uses only watershed area for correlations. The project area is several miles long and watershed area increases greatly from the upstream to the downstream end. The watershed was divided into three major contributing sub-watersheds Natural Channel Design, Inc. 7 March 2008

12 for analysis. The sub-watersheds are delineated in Figure 5. Results from both models are based upon the combined area of the sub-watersheds contributing to each reach. Figure 5. Canyon Creek project area watershed delineations. The watershed was divided in three main contributing sub-watersheds. Downstream demarcation for each sub-watershed is: A- Hatchery Bridge, A+B The OW Bridge, and A+B+C confluence with Valentine Canyon. Results from NFF and Regional hydrology methods provide reasonably consistent estimates for flood frequencies in the three reaches. The regional method always provided higher magnitude estimates for a given flood frequency. However, the regional method results were usually within the error estimates provided by the NFF procedure. Both sets of results are displayed to provide an estimate of the general magnitude of flows for a given frequency. Results for each model are in Tables 9 and 10. The results indicate that the watershed above the project reach can produce significant flood volumes during infrequent flood events. Natural Channel Design, Inc. 8 March 2008

13 Table 1 Estimated discharges using NRCS regional hydrology The NRCS regional hydrology method used stream flow data from eight gaged sites along the Mogollon Rim. Sub-watersheds are depicted in Figure 12. WS Area Q 1.5 Q 2 Q 5 Q 10 Q 25 (sq miles) (cfs) (cfs) (cfs) (cfs) (cfs) A A + B A+B +C Table 2 Estimated discharge using NFF V 3.2. Discharge estimates are given in cubic feet per second (cfs) with standard errors in parenthesis. Subwatersheds are depicted in Figure 12. WS Area Q 2 (SE) Q 5 (SE) Q 10 (SE) Q 25 (SE) A (110) 407 (68) 724 (52) 1390 (40) A + B (110) 611 (68) 1070 (52) 2010 (40) A + B + C (110) 1090 (68) 1870 (52) 3430 (40) The flood history of the stream provides a helpful framework for assessing the geomorphic response to floods of different magnitude. Major flooding has occurred in recent decades and can be linked to changes in the stream s geomorphology. Examination of regional gage data indicates that streams around Canyon Creek likely experienced flooding events approximating a 10 to 20 year event in Flooding during 1993 was somewhat larger (approximately a 25 to 30 year event), and 1995 experienced approximately a 10 year recurrence interval event. Flooding after the Rodeo Chediski fire in 2005 was again, likely of the 5 to10 year recurrence interval magnitude. Other streams in the region also experienced significant flooding recently (winter of ). Nearby Tonto Creek experienced discharges approximating a flood with a 10 year recurrence magnitude. Natural Channel Design, Inc. 9 March 2008

14 GEOMORPHOLOGY Alluvial stream channels are created and maintained by the processes that move sediment and water produced by their watersheds (Leopold 1994). These processes produce characteristic morphological patterns. Channel slopes/bedforms and cross-section shape/dimension were characterized by Level II longitudinal profiles and cross-section surveys and classified using the Natural Channel Classification System (Rosgen 1996). Six longitudinal profiles and associated channel cross sections were analyzed as part of this assessment (Figure 6). Four cross sections are permanently marked and resurveyed by USFS personnel. These surveys allowed assessment of recent channel changes. Two additional surveys were measured by Natural Channel Design. One was measured in 2003 during another study and an additional survey was conducted during late 2007 as part of this project. The NCD profiles do not provide a time series of data, but they do allow assessment of reaches not surveyed by USFS. Canyon Creek is a single channel stream with occasional split channels or flood channels. The predominant bed forms are runs and riffles with very few pool habitats below OW bridge. Data from the profiles and cross sections indicate that the slope of Canyon Creek is approximately 1.5 percent above the OW Bridge and decreases to approximately 1 percent below the bridge through the meadow area. The stream has low to moderate sinuosity, with bankfull channel widths ranging between 30 and 65 feet. The stream is generally wide with moderate to high width/depth ratios and only slightly entrenched. The valley floor is generally quite wide so the stream has good access to floodplains and terraces. The substrate is composed of large gravel to cobble sized stones. Results of geomorphic surveys are given in Table 4. Inspection of cross section repeat surveys conducted by USFS indicated the channel has been relatively stable for the last three years. Only one cross section of the four indicates the channel has experienced scour in the last three years. This scour appeared local to the area around the cross section and all other cross sections remained stable for the monitoring period. A number of abandoned channels suggest that Canyon Creek has migrated over the valley floor within the last several decades. Most evidence of migration occurs in the reach below OW Bridge and the migration may have been accompanied by some local channel incision in the reach immediately below the bridge. Log fish habitat structures were built in this reach in the late 1980 s and were likely destroyed during large flood events in Some channel scour occurred during that event or afterwards since the bottom of the remaining log structures are now feet above the bed of the stream. In a less steep reach immediately downstream of the log structures, there is evidence that the stream has cut off a meander bend, creating a short length (~ 350 feet) that has a steeper grade than the surrounding reach. In most other areas recent changes to the stream are the result of local bank erosion or shifting of base flow to old flood channels. As a result, there are some examples of steep cut banks and wide, shallow areas of the channel as the stream transitions from one flood channel to another. In most cases the toes of the banks are becoming vegetated with willows, grasses or emergent plants. Natural Channel Design, Inc. 10 March 2008

15 Figure 6. Geomorphic survey locations in Canyon Creek. The figure shows approximate locations of geomorphic surveys in Canyon Creek project area. Four permanent cross sections are currently resurveyed by USFS, one cross section was surveyed by NCD in 2003 and another was surveyed in 2007 as part of the current project. Natural Channel Design, Inc. 11 March 2008

16 Table 3. Channel dimensions for survey sites in Canyon Creek. Surveys were conducted by both Natural Channel Design as well as US Forest Service. Data shown with permission of Grant Loomis, USFS. Locations of sample sites given in Fig. 12. NCD 2008 upstream USFS above exclosure USFS upstream in exclosure USFS downstream in exclosure USFS below exclosure NCD 2003 downstream WS (sq mi) Bankfull Area (sq ft) Slope (ft/ft) Bankfull width (ft) Mean Depth (ft) Max Depth (ft) Entrenchment ratio > W/D ratio Sinuosity Rosgen Channel type B4c C3 C3 C3 C3 C4 1 Entrenchment Ratio is defined as floodprone width divided by bankfull channel width and describes the floodplain area available for spreading moderate flow events. 2 Width-Depth Ratio is defined as bankfull channel width divided by mean bankfull depth and describes the bankfull channel shape. Ratios of pool, riffle, and run bedforms are helpful to characterize fish habitat. Riffles are bedforms with slopes steeper than the general slope of the stream, while runs have slopes that are roughly equal to the average channel slope. Pools have slopes that are less than the average slope of the channel. These ratios were measured by locating the upstream edge of each feature with a GPS unit then using GIS to measure the thalweg distance between each feature. Ratios were estimated from a representative sample of the lengths of each feature type. The stream above the Hatchery Bridge is relatively steep with frequent step-pool features and pool/riffle ratios were not measured. The stream below the Hatchery Bridge has a much lower slope and generally fewer pool habitats. Canyon Creek below the hatchery bridge is dominated by run and riffle habitat Natural Channel Design, Inc. 12 March 2008

17 with very few pool habitats. Pool habitats are longer in the reach below OW Bridge, however many of the pools were quite shallow for most of their length. Length ratios for different habitats are given in Table 11. Table 4. Length of stream for pool, riffle and run habitats. Pool Riffle Run Hatchery Bridge to OW Bridge OW Bridge to Valentine Canyon 17% 30% 53% 26% 31% 43% Pebble count data from the recently surveyed cross sections indicates that the stream substrate is generally large gravel or small cobble. Re-surveys of pebble counts by USFS indicates that the D 50 has increased, which suggests that there has been some general coarsening of bed material since Generally, the fine silts and sands which appeared in surveys during 2005 have since been removed from the stream. A visual survey of the entire project area indicate very little accumulation of fine sediments within the open channel. The margins of the channel have dense growth of watercress (Nasturtium officianale) along much of the stream. These stands trap considerable amounts of sediment within their root matrix and may also be constricting the flow of water to the center portion of the channel. A late fall visit after frost showed that much of the water cress had died back, which allowed the trapped sediment to be re-entrained by the stream. In summary, the channel appears to be relatively stable except for periodic, high flows that have the potential to cause channel migrations (mainly between current and abandoned flood channels). Whether this response is the natural condition of the stream, or a result of heavy grazing and land use changes in the past century, is unknown. However, it appears that the response to flooding after the Rodeo-Chediski fire is not unlike what has occurred in response to other flooding events. The floodplains are wide and low. High flood discharges predicted by the hydrology models should have ample room to spread across floodplains and minimize extremely high velocities and depths. Additionally, the stream seems to be recovering along cut banks and other recently destabilized areas. Willows, grasses, and sedges are becoming established along the toe of most of the banks. The stream appears of have cleared many of the fine sediments that accumulated in response to the fire. Natural Channel Design, Inc. 13 March 2008

18 FISH HABITAT ASSESSMENT Fish habitat assessment was conducted by review of existing materials, geomorphic analysis, and a visual assessment of the stream during Fall We used Raleigh et al. (1986) as a reference for optimal Brown trout conditions. We recorded which areas of the stream had deficient habitat and which areas contained suitable habitat or features that contribute to suitable habitat. Natural conditions that created suitable habitat were also recorded and used to develop prescriptions for areas that were not maintaining suitable habitat. Water quality is not likely a limiting condition for Brown trout in Canyon Creek. The few measurements of conductivity and ph that are available indicate that both are within the range of conditions tolerated by Brown trout. Temperature may be limiting to Brown trout growth and survival. Recorded temperatures in the lower portion of the project site are outside of the optimal growth range for juveniles (7-19 C) for large portions of the summer and can approach lethal temperatures of 29 C for short periods. No assessment of dissolved oxygen was made, however it may also be limiting at higher temperature levels. The short reach of stream from the springs to the hatchery is partially dewatered and currently has little value as trout habitat. Additionally, many pool features have been filled with sediment even though the reach is steep enough to maintain pools (Figure 7). If pool habitats could be maintained, even the partial flows available would likely provide habitat for fish. Figure 7. Aggraded pools upstream of Hatchery. Geomorphic analysis shows that Canyon Creek from the Hatchery Bridge to Valentine Creek is relatively wide and shallow with very few pool habitats (Figure 8). Riffle and run habitats dominate the stream. Accordingly there is very little deep, low velocity habitat, which is preferred by adult Brown trout. Major portions of the stream are less than the minimum 0.5 feet in depth and faster than the 0.5 ft/sec velocity recommended as a minimum for adult Brown trout (Raleigh et al, 1986). Run habitats are plentiful and provide adequate depth suitable to Brown trout but lack complexity and cover. These conditions are especially critical during base flow conditions. Much of the stream below OW bridge has relatively little heterogeneity like large boulders or wood that create mid stream resting habitats, so fish must rely on the limited deep Natural Channel Design, Inc. 14 March 2008

19 pools or shoreline habitat. Shorelines are still developing mature vegetation that could provide future overhead cover, but much of the stream has developed very little vegetation canopy since the fire. Canopy conditions are better above the OW Bridge and improving within the elk exclosures downstream of OW Bridge. However, the reaches below OW Bridge that are not protected by elk fencing have limited shade and cover vegetation. Overall, shallow depths and lack of shade contribute to increased stream warming through this reach. Figure 8. Typical fish habitat below OW Bridge. Stream is dominated by relatively shallow riffle and runs with few pools. Limited availability of spawning substrate is a concern in Canyon Creek. Previous surveys by Gill (2006b) and our survey indicate few active redds and limited availability of suitable sized substrate. The survey also suggests that supply of gravel is not limited. Tributaries to Canyon Creek have ample sediment to supply to the stream and we were able to find areas within the stream that provided proper spawning substrate. Suitable sized gravel was also found on small bars along the stream margin (above base flow elevation) and at the outflow of several pools. Additionally, suitable substrate was found below the coarse substrate in the streambed. These observations indicate that there is an adequate supply of sediment to the stream, however the morphology of the stream appears to produce velocities that do not allow gravel to be deposited in a manner that is useful to spawning habitat. Either the gravels are deposited along stream margins above the low water elevation or are winnowed out of riffle and run habitats during flood events. Visual assessment of the stream, as well as an interview with an angler that has fished Canyon Creek for several decades, indicates that several key habitat features are important to supporting fish populations in Canyon Creek. Rusty Knot of Flagstaff recalled several habitat features of Canyon Creek he considered beneficial to trout. Watercress provides cover for smaller fish and medium sized fish. Extensive stands of watercress have persisted in Canyon Creek for many years. Pool habitats are important to fish but have never been abundant in Canyon Creek downstream of OW Bridge. Root wads and fallen logs provided cover as well as small over-hanging banks. Natural Channel Design, Inc. 15 March 2008

20 Our visual assessment agrees with the observation that watercress provides important cover in shallow riffle sections and is likely utilized by small to medium sized fish. The streambed affords many interstices and small, low velocity habitats for these smaller fish. Smaller trout and dace were also found in the margins of runs and riffles especially in areas that contained watercress (Figure 9). There appears to be adequate young of year and juvenile trout habitat available in Canyon Creek since these habitat types are plentiful. Figure 9. Watercress patches in Canyon Creek. Watercress provides cover for small fish, captures fine sediment and constricts flow, providing greater depth in center of channel. Deeper pools utilized by larger fish are few and scattered. Smaller, local habitats are created primarily by fallen logs, which create overhead cover and scour pockets in the channel. Fallen trees that crossed completely over the stream also helped create deep pools by forcing flows into the bed, scouring the substrate (Figure 10). Occasional larger boulders in the channel also appear to provide resting habitats with lower velocities and vertical or overhead cover. Midstream boulders can create small scour pockets with deeper habitat for one or two fish. Natural Channel Design, Inc. 16 March 2008

21 Figure 10. Fallen log creating pool habitat. Logs crossing over the stream create deep habitat with overhead and vertical cover. Many of the deeper pools below the OW Bridge did not appear to be heavily utilized by trout because the bedrock along the bottom of the pool did not afford any hiding cover and fish were forced to be in the open. Consequently, both native sucker and trout use of these pools was limited to the very deepest portions. (> 2.5 ft). In summary, hiding and resting habitat for adult trout appears to be limiting to the fishery in Canyon Creek. The stream morphology is wide, generally shallow and not currently, nor historically, conducive to formation of large pools. Extensive watershed damage from wildfire appears to have temporarily impacted hydrology and sediment supply though the system is recovering. Increased stream temperatures may also limit trout growth especially in the lower portion of the project site. Elevated temperatures are exacerbated by the high width/depth ratio of the stream and the lack of vegetation shading the stream. While pool habitats are lacking, trout do utilize available cover provided by logs and scour pockets associated with the few large boulders in the stream. While these habitats are not numerous within the stream, it appears that the morphology and hydrology of the stream will support them in greater numbers. Improving habitat conditions for trout should be aimed at emulating existing features within the stream that are utilized by trout and expanding the distribution of these features. Natural Channel Design, Inc. 17 March 2008

22 RECOMMENDATIONS Stream conditions in Canyon Creek are improving from the degradation previously caused by wildfire in the watershed and subsequent flooding. The morphology of the stream appears relatively stable with access to the geomorphic floodplain and few unvegetated cut banks. The existing eroded banks appear stable and vegetation is forming along the toe. Vegetation is becoming re-established in many areas of the stream. While the general stream habitat is improving, specific fish habitat components are not improving at the same rate and may not improve without management action. Trout habitat improvement in Canyon Creek should have three main goals: To improve the availability of resting/hiding habitat for adult trout during low base flows. To improve shading of the stream to ameliorate high temperatures in the lower portion of the project site. To improve the availability of spawning substrate. Previous actions to improve adult trout habitat in Canyon Creek were centered on building drop structures and cover from large logs. The lifespan of these structures was relatively short compared with the expense and effort to install them. Log structures below OW Bridge were installed in the late 1980 s and destroyed by a large flood in 1993 (Figure 11). Visual surveys and historical accounts indicate that Canyon Creek does not maintain deep, extensive pool features. Existing pools are not large, deep, or numerous and it appears that smaller diverse habitats naturally provide the depth, cover, and velocity preferred by larger trout. It is recommended that habitat improvement for adult trout focus on reproducing these types of habitats. An emphasis should be placed on producing multiple, small habitats, which are inexpensive to build, rather than fewer, larger, expensive habitat features. The history of expensive habitat features in the Southwest repeatedly illustrates that large structures seldom last long given the hydrology of the region. Smaller features are likely to be just as ephemeral, however they are less expensive to build and can be rebuilt multiple times for the same relative cost as a larger feature. Additionally, multiple small features can spread habitat out and increase overall habitat diversity. They also can be built with minimum impacts to a stream that is already recovering from multiple stressors. Figure 11. Remains of engineered log structure. Log structures were built during the late 1980s and were destroyed by flooding in the early 1990 s. Natural Channel Design, Inc. 18 March 2008

23 Logs and boulders can be placed in the channel in a manner that emulates structures existing naturally in the stream. Many of these placements may shift at flood discharges. However, it is likely that logs and boulders supplied to the system will remain within the system, creating new habitat features where they come to rest. Structures placed in areas of active or probable bank erosion should also provide protection from high velocity flows and promote vegetation establishment on the bank. It is recommended that enhancements be placed within the stream in phases as part of an ongoing habitat maintenance project which is funded frequently at low levels rather than a large single period of funding. Construction periods should occur every 2-3 years and be informed by ongoing monitoring of stability and fish utilization of previously built structures. Additionally, initial phases of construction should be focused on specific reaches of the stream in an effort to concentrate a number of habitat features in a specific area, maximizing the effects of the enhancement on both fish and anglers. The extent of habitat improvements can be modified from year to year depending funding priorities. Promotion of the growth of vegetation that provides cover to the stream is also an important aspect of the project. Vegetation is rapidly reestablishing inside the elk exclosures and will provide increased shade to the stream in these reaches. However there are areas outside of the exclosures that would benefit from pole planting of cottonwoods and willows. Pole planting of native willows and/or cottonwoods should be a part of the installation of all structures since the plants will provide additional cover and the roots will provide additional stability to the structure and the surrounding bank. However, grazing pressure is high outside of the exclosure and establishment may be limited without additional, expensive fencing. Expanding spawning substrates is problematic. This study suggests that gravel supply is not a limiting factor to the project reach, but homogeneity in channel morphology limits the deposition and maintenance of these habitats. Existing areas of suitable spawning habitat were observed to be associated with logs, rocks, or other obstructions to flow. These components interrupt downstream velocities creating local areas of deposition for finer gravels. This observation suggests that creating greater heterogeneity of flow with the addition of large rocks and logs can create a diversity of substrate conditions, especially when conditions emulate the outflow of a pool. Raleigh et al. (1986) suggest that spawning area size be approximately 220 sq ft. (~15 ft X 15 ft). Log structures extending across the stream can create this size patch. However, many of the smaller boulder clusters may not create a continuous patch this large. Observations of spawning redds in Canyon Creek indicate that local redds are considerably smaller than the guidelines provided by Raleigh et al. The recommended practices for adult trout enhancement will likely also produce suitable spawning substrate. Our analysis suggests that augmentation of gravel supply to the stream is not likely to be sustainable practice given the cost of gravel and the continual reworking of gravel beds by stream flows. However, continued monitoring of redd development and substrate availability is highly recommended. If conditions do not improve after habitat enhancements, other methods to create sufficient sized spawning grounds with proper sized gravel may be required. The reach with the highest priority for enhancement is between OW Bridge and Valentine Creek since it contains the lowest proportion of pool habitats and less cover. This reach also has high angler use and accessibility. The short reach upstream of the hatchery should also be considered for enhancement although at a lower priority. This reach would benefit from excavation of pools which have filled with sediment. Excavation would not be aimed at building new habitat, only Natural Channel Design, Inc. 19 March 2008

24 helping the stream restore existing pools that have aggraded due to excess sediment load from the burned hillsides. While excavation would speed up the process of rebuilding pools, the stream is likely to do it on its own given enough time and adequate flows. MONITORING Monitoring is an important aspect of this project. Regular monitoring of structural longevity and use by fish as well as the overall effect on fish populations will not only inform successive phases of habitat improvement in Canyon Creek but can provide an important contribution to fisheries habitat management. This approach to habitat improvement in Canyon Creek is novel. Careful documentation of its successes and failures will provide guidance for many other projects, especially in the Southwest. Annual monitoring of adult numbers, habitat use, spawning success as well as physical characteristics of water quality, movement of large woody debris, structural longevity and utilization are all needed to inform future Canyon Creek work and other projects. PRESCRIPTIONS FOR POTENTIAL IMPROVEMENTS The following prescriptions were developed for use in Canyon Creek. All prescriptions are designed to mimic existing high quality habitat for trout and utilize local materials and minimum disturbance to the stream and riparian area. Written descriptions of each practice are provided below. Detail drawings are provided in Appendix A. Installation of the habitat enhancements will require the use of machinery to handle excavation, banksloping and handling of logs. Machinery is also suggested to assist with planting of cottonwood and willow poles. All the areas along the stream are accessible to track machinery, however small portions of fence may have to be temporarily be removed and rebuilt. Root wad Root wads are the boles of large mature trees embedded in the stream bank with the attached root wad extending out into the stream. The buried bole anchors the structure and the mass of roots slows velocities along the bank, creates a scour pocket in the stream bed, and provides both vertical and overhead cover for fish. Root wads are usually installed along the outer bank of a meander bend and can be installed in series when necessary. Trees need to be inches in diameter and have at least 10 feet of bole to bury in the bank. The number of root wads to be installed is dependent on the availability of suitable trees. Trees can be damaged or downed wood but should be sound. Log overhang Log overhangs are used to provide overhead cover during low water periods. They consist of a inch log placed parallel to the flow of the stream slightly imbedded in the toe of the bank. The log rests on footer logs, buried in the stream bank that create an open cavity along the stream bank. Rock clusters and planting provide shade and cover over the structure. Placement is on the outside of meander bends that provide enough current to prevent the cavity from filling with sediment. The overhang should be constructed to be at or below water level at base flows. The length of the structure is variable based upon the site and several structures can be placed in series. Cross-over log The cross over log is a large log perpendicular to the flow of the stream and extending from one stream bank to another. The log can be held in place by either the attached root wad and upper limbs, or ballasted with large rocks. The trunk of the tree should be at or slightly above water level at base flow. Higher flows will create a jet under the log maintaining a scour hole in the Natural Channel Design, Inc. 20 March 2008

25 substrate. Flows will also be forced around the ends of the logs creating small pockets of scour near the banks. Vertical and overhead structure are formed by the trunk and roots of the tree. Habitat heterogeneity created by the cross-over log also helps to form variable stream velocities, which maintain different substrate size distributions in the channel. Cross-over logs will likely be shifted by the stream during large flows. However, in Canyon Creek there is little infrastructure that can be damaged by floating logs and they will likely create new habitat where they come to rest. Best placement for cross over logs are in riffles or runs located in relatively straight sections of the stream. Loose crossed logs Several pools and runs in Canyon Creek are scoured to bedrock on the bed and have bedrock along one bank. While depths are sufficient for trout habitat there is no overhead or vertical cover. This structure is designed to provide overhead cover and shade to these pools. The structure consists of at least two logs spanning the stream and crossed at mid stream. The butt end of the logs are lodged in natural crevices in the bedrock bank and the top ends are buried in the opposite stream bank with limbs intact. The logs should be elevated above the water level at base flow yet low enough to provide shade and cover over the pool. The logs are pinned together at the mid point to provide stability to the structure. The likelihood that the logs will be shifted during infrequent high discharges is great. Because the structure is held together with a minimum of pinning or cable it should pull apart when stressed and not create a significant logjam. The materials will likely stay within the system and become lodged elsewhere to create other habitat. Log barb The log barb provides both bank protection and fish habitat features along the outside of a bend. It consists of a single medium to large sized tree trunk buried in the bank and sloped upstream and down towards the bed of the stream. The end in the river should be buried in the substrate or held in place with ballast boulders. The barb should not extend over one third the stream width into the stream. The upstream side of the barb can be ballasted with large cobbles and boulders. The barb serves to slow velocities along the outside of the bend and create a slow water habitat. By building the barb from a log the downstream side can provide a hollow, overhung area for fish hiding. The area just downstream of the barb should be excavated slightly at installation to initiate a small pool. Currents created by the barb should maintain the pool over time. The banks should be planted with willow poles to strengthen the bank and provide additional overhead cover. Several barbs can be used in succession along the outside of meanders. Rock barb Rock barbs provide the same function as log barbs but are constructed of interlocking boulders. Again the barb should angle upstream and down into the streambed without extending more than 1/3 the distance across the stream. The bank should be planted with willow poles to provide additional cover and shade and the area below the barb should be excavated slightly to initiate habitat building. Boulder clusters Boulder clusters create heterogeneous currents and velocities in homogenous riffles and runs. They can provide vertical cover in midstream or bankside habitats. Three to four large boulders are placed in a group to breakup high velocities and create low velocity resting habitat with vertical structure. The area immediately downstream of clusters can be excavated slightly to provide deeper habitat, which will be maintained by the cluster. Boulder clusters can be installed midstream or along the shoreline. They are best used in groups of densely spaced multiple clusters to provide short reaches of complex habitats. Natural Channel Design, Inc. 21 March 2008

26 Mini weir The mini weir is a specially constructed boulder cluster that concentrates small portions of the flow and passes them over a footer rock to create a small scour hole in relatively homogenous runs and riffles. They consist of two larger boulders on either side of a lower boulder dug into the streambed. The area downstream of the weir should be excavated at installation to create a scour hole in the streambed. Flows concentrated by the mini weir will maintain the scour. Weirs should be placed in riffles and runs in sets that create complex flow patterns. Pool excavation There are several opportunities in Canyon Creek to enhance existing pools for depth and extent. Excavation should be used to initiate pool building in areas that have the potential to have flows maintain the excavation over time. Excavation should be aimed at areas which already have shade and cover, but lack depth to provide proper trout habitat.. Bank sloping Bank sloping is used to help establish vegetation on overly steep bare banks. Vegetation (seed and pole planting) is much more successful when banks are stable and slope at a minimum 2:1 slope. An excavator works from the top of the bank and pulls material up and away from the stream to minimize sediment entry into the stream. Spoil can be spread in the overbank area away from the stream. Slope banks require reseeding and pole planting with native grasses, forbs and willow or cottonwood poles. Erosion control fabric helps to prevent erosion of the raw bank until vegetation can become established. Bank sloping can benefit the stream by helping to establish vegetation that prevents sediment entry to the stream while providing shade and cover. Brush revetment Brush revetment promotes the storage of sediment along the toe of the bank by slowing stream velocities, especially on the outside of meanders. Build-up of sediment along the toe allows establishment of vegetation and strengthens streambanks. It can also provide temporary low velocity cover for small fish. Brush revetment consists of stout evergreen limbs (juniper limbs or recycled Christmas trees) fastened together to provide a continuous row along the toe of the bank. The revetment is held in place with either T-posts or ground anchors. The limbs slow velocities and trap sediment. When the toe is established, the limbs either rot or become buried in sediment. T-posts and other anchoring can be removed as necessary. Willow pole planting Planting of native willow and cottonwood poles are an economical way to rapidly establish vegetation along stream banks. Locally harvested dormant poles can be planted with an auger or backhoe into permanently wetted soil along the bank. The dormant poles will root and establish new trees within a several growing seasons. Poles need to be harvested during the dormant season (winter) but can be stored for several months before planting if treated properly. Disturbed bank areas and areas around new habitat structures should be planted with at least a single row of poles. The new vegetation will provide shade, cover and streambank protection. Pole planting on freshly worked banks should be accompanied by seeding with a mix of local native grasses and forbs POTENTIAL AREAS OF ENHANCEMENT Sites for habitat enhancement were located and prioritized by a walk-through inspection of the stream. Locations were marked with GPS unit and mapped in GIS. The type of habitat Natural Channel Design, Inc. 22 March 2008

27 enhancement and number of treatments (or feet of bank) were noted for each site. All sites for habitat enhancement are located between OW Bridge and Valentine Creek with the exception of the short reach between the springs and hatchery. Figure 12. Location of sites for habitat improvement in Canyon Creek. Locations for upstream portion of the project site. Specifics given in Table 5. Natural Channel Design, Inc. 23 March 2008

28 Figure 13. Locations of proposed habitat improvements in Canyon Creek. Locations for downstream portion of project site. Natural Channel Design, Inc. 24 March 2008