Chapel Slide Restoration

Transcription

1 Chapel Slide Restoration 2014 Post Run-off Monitoring Report Chapel Slide Restoration Reach during the Spring Runoff of 2013 US Department of Agriculture Kootenai National Forest Cabinet Ranger District July 7,

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3 Prepared By: Craig Neesvig District Hydrologist Cabinet R.D. Trout Creek, MT TABLE OF CONTENTS 1.0 Introduction 1.1 Existing Condition Prior to Restoration 1.2 Connected Downstream Instability 1.3 Project Design 1.4 Reference Reach Descriptive Information 1.5 Hydraulics and Sediment Transport Restoration Activities 1.7 Riparian Revegetation 1.8 Timing, Duration and Permitting 1.9 Water Years 2013 and 2014 Runoff Monitoring 1.10 Dimension, Profile and Photo Monitoring 1.11 Project Channel Dimensions 1.12 Reference Channel Dimensions 1.13 Stream Channel Succession 1.14 Project Channel Profile 1.15 Reference Channel Profile 1.16 Substrate Monitoring Project Reach 1.17 Substrate Monitoring Reference Reach 1.18 Conclusions 1.19 References List of tables Table 1.1 Existing Morphological variables at the Chapel Slide project site. Table 1.2 Summary of reference reach variables by site. 2

4 Table 1.3 Summary of Design Dimensions. Table 1.4 Particle size distribution above the project site. Table 1.5 Equipment time and materials cost for the Vermilion River Chapel Slide reach restoration. Table 1.6 Planting, Irrigation and Maintenance Cost Summary for the Vermilion River Chapel Slide reach restoration. Table 1.7 Stream Channel Construction and Riparian Revegation Project Duration. Table 1.8 monitoring items for the Vermilion River Chapel Slide reach. Table 1.9 monitoring items for the Vermilion River Reference reach. Table 1.10 Summary of monitored project dimension reach variables Table 1.11 Summary of monitored reference dimension reach variables Table 1.12 Comparison of Vermilion reference and Chapel Slide dimension reach variables Table 1.13 Vermilion stream successional threshold values derived from reference reaches within the Cabinet and Libby Ranger Districts. Table 1.14 Dimensionless project reach variables Table 1.15 Summary of monitored pattern and profile As-built reach variables Table 1.16 Summary of monitored pattern and profile reference reach variables Table 1.17 Riffle and reach particle size distribution within the project reach. Table 1.18 Riffle and reach particle size distribution within the upstream reference reach. Table 1.19 Comparison of Vermilion reference and Chapel Slide substrate reach variables List of Figures Figure 1.1 The Chapel Slide reach Vermilion River channel restoration project location. Figure 1.2 Chapel Slide Figure 1.3 Chapel Slide Figure 1.4 Pre-restoration existing condition within the Chapel Slide reach of the Vermilion River. Figure 1.5 Chapel Slide representative cross section and associated shear stress values prior to restoration. 3

5 Figure 1.6 Existing reference channel conditions above the Chapel Slide reach of the Vermilion River. Figure 1.7 Design planform of the Chapel Slide reach of the Vermilion River. Figure 1.8 Chapel Slide design cross section and associated shear stress values. Figure 1.9 As-built channel within the Chapel Slide restoration reach of the Vermilion River one year post run-off. (Looking upstream from station 4+00). Figure Temporary access road utilized for the Chapel Slide restoration. Figure Temporary water diversion utilized for the Chapel Slide restoration. Figure Materials stockpile at staging area and within the immediate project work site. Figure Riparian vegetation in the Chapel Slide reach 1 month post planting. Figure Riparian vegetation fenced enclosures at the base of the Chapel slide utilized on the recently constructed floodplain. Figure Hydrograph of the Vermilion River for water year Figure Hydrograph of the Vermilion River for water year Figure 1.17 Monitored post runoff riffle cross section #1 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.18 Monitored post runoff riffle cross section #2 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.19 Monitored post runoff riffle cross section #3 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.20 Monitored post runoff riffle cross section #4 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.21 Monitored post runoff riffle cross section #5 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.22 Monitored post runoff riffle cross section #6 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.23 Monitored post runoff riffle cross section #7 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 4

6 Figure 1.24 Monitored post runoff riffle cross section #8 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. Figure 1.25 Monitored post runoff riffle cross section #1 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking downstream). Figure 1.26 Monitored post runoff riffle cross section #2 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking downstream). Figure 1.27 Monitored post runoff riffle cross section #3 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking upstream). Figure 1.28 Monitored post runoff riffle cross section #4 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking upstream). Figure Dimension variable percent change within the project and reference reach through 2013 and Figure Vermilion Project Reach longitudinal profile of 2013 and Figure Vermilion Reference Reach longitudinal profile of 2013 and Figure Substrate variable percent change within the project and reference reach through 2013 and

7 1.0 Introduction The Vermilion River is a major tributary to the Lower Clark Fork River (see Figure 1.1) and lies in the Northwest corner of Montana. The Vermilion River is a perennial fourth order stream draining a watershed influenced by land uses including historic and ongoing placer mining as well as commercial forestry. The Vermilion River is one of only a few fourth order drainages in the Lower Clark basin that ensures perennial streamflows throughout the length of the mainstem. The stream flow runoff regime, in particular spring runoff, is periodically influenced by rain-on-snow and rain on snowmelt events that can occur anytime during the winter months in response to warm air temperatures and rain. Typically, however the peak flow event occurs in May or early June. Figure 1.1 The Chapel Slide reach Vermilion River channel restoration project location. Montana s (d) list classified 22.5 miles of the Vermilion River as impaired and only partially supporting its beneficial uses of aquatic life and cold water fisheries. At this time sediment was listed as the pollutant of concern in the watershed. In 2005, the Lower Clark Fork River Drainage Habitat Problem Assessment ranked the Vermilion River as the highest priority for improving and protecting native fish habitat in the Lower Clark Fork drainage. In 2007, the District in cooperation with Avista and Montana Fish, Wildlife and Parks completed a watershed assessment that analyzed current geomorphic, vegetative, sediment and fisheries conditions and prioritized restoration projects in the Vermilion drainage with a focus on sediment reduction and improving populations of native bull trout and westslope cutthroat trout. This analysis and further reference sediment data collected in the Lower Clark Fork confirmed that fine sediment levels in the lower mainstem of the Vermilion River are currently above reference conditions and may be affecting native salmonid habitat. 6

8 Figure 1.2 Chapel Slide 2005 Figure 1.3 Chapel Slide 2009 Within the assessment the highest priority site identified for restoration was the Chapel Slide, a large (300 long, 140 high) eroding mass waste that delivered approximately 712 tons per year of fine sediment (under average flood conditions) into a high priority Bull trout spawning area just below Vermilion Falls. Located approximately 0.75 miles below Vermilion Falls, this site was the single largest sediment contributor in the Vermilion drainage, accounting for over 80% of all sediment produced in Reach 6. This is of concern because although reach six is the most important bull trout spawning area in the Vermilion River, it has limited pool depth and frequency, poor substrate quality, and relatively little LWD. In addition, effects from these sediment inputs may currently be compromising downstream spawning habitat. In 2008, a year of above average runoff, approximately 7100 tons of sediment was produced. The river was actively eroding the toe of the slide and a vertical face approximately 65 feet high has developed that is extremely unstable and vulnerable to additional mass failure. Numerous entities were involved from project initiation to project completion. Outside funding mechanisms included grants from Avista Utilities, Montana Fish Wildlife and Parks (MFWP) Future Fisheries Improvement Program, National Fish & Wildlife Foundation Bring Back the Natives, National Fish Habitat Action Plan, Sanders County RAC, and the Kootenai National Forest. The combination of funding sources allowed for this project to occur. Although the USFS Cabinet Ranger District took the lead on this project, deliverables would have not been attainable without the involvement and similar goals of these outside agencies. During the summer of 2012 employees from the Cabinet and Libby ranger districts initiated channel realignment and stream restoration activities within a portion of reach 6 of the Vermilion River. Approximately 500 feet of new channel was constructed over the course of three weeks. With the exception of the materials staging area, which was granted on adjacent Plum Creek Timber land, all portions of the project were on national forest land. This report outlines trends through the first two years of runoff and will assess progress toward achieving restoration success as recommended in the Vermilion watershed assessment. Although this report summarizes the first 2 years post construction, monitoring will continue until final vegetative and inchannel success is attained. 7

9 1.1 Existing Condition Prior to Restoration Prior to the 1997 runoff season (which harbored one of the largest events in the period of record (roughly a 50 year flood event)), this area of the Vermilion River noticed sediment entrainment at a more subtle rate. The slide area, which to a lesser extent did exist at this time, was located on the right bank of a deep riffle that limited the amount of near-bank shear stress. This bank stress was thought to be similar to what would be expected in a reference location. It is thought that the 1997 event exacerbated the slide area when a log jam formed at the slide area and fashioned a temporary vortex that increased local shear stress at the toe of the slide. At this time the main river channel had migrated to the base of the hillside. The hillside mostly composed of homogenous sand and fine gravel began to destabilize and, through a series of rotational hillslope failures, allowed the channel to laterally migrate into the slide roughly75 feet. Figure 1.4 Pre-restoration existing conditions within the Chapel Slide reach of the Vermilion River Prior to destabilization the Vermilion River in this area supported a multi-aged riparian community including serviceberry, Sitka Alder, black cottonwood, and various conifers. The channel above the project reach exists as a confined Rosgen type B3 channel with average width/depth ratios being noticed that currently transport sediment efficiently. Before restoration the project site existed as an overwidened channel with high width to depth ratios. The banks throughout this area are composed of mostly gravel and sand with limited amounts of cobble. The natural channel slope within the project reach was roughly 2 % before restoration. 8

10 XS# Bankfull Width Table 1.1 Existing Morphological variables at the Chapel Slide project site. Floodprone Width Entrenchment Ratio Mean Depth Maximum Depth Width/Depth Ratio Bankfull Area Water Surface Slope Mean Figure 1.5 Chapel Slide representative cross section and associated shear stress values prior to restoration The riparian corridor remained intact until reaching the project site where the exposed mass waste on the right bank supplied constant fine sediment under all flow conditions. Prior to the 2012 restoration, this area of the Vermilion had transitioned more toward a overwidened C type Rosgen system rather than the original B or Bc transport type channel that it historically was. This channel evolution led to the increase in shear stress at the toe of the slide and subsequent continual mass wasting. 9

11 The fish habitat complexity consisted of an overwidened riffle and minimal, functional in-channel Large Woody Debris (LWD). The 1996 event, along with the over-bankfull type flooding that occurred during the spring of 2008, is thought to have been the major contributors to the degraded condition of this reach. 1.2 Connected Downstream Instability Shortly downstream of the Chapel Slide area, effects from historic mining can be noticed within the mainstem. The Miners Gulch reach has experienced a level of sediment deposition directly related to the unraveling of the Chapel slide. Numerous field investigations and time series air photo analysis have confirmed that the majority of sediment produced from the Chapel Slide during water years has been transported downstream through the 1.5 miles of higher gradient channel and deposited directly to the Miners Gulch area below, the next area of restoration focus. This connected downstream area aided in project design. 1.3 Project Design The mass waste that existed directly adjacent to this channel was actively contributing fine sediment downstream to Miners Gulch. The size and progression of the wasting hillside drove alternative development and led to the total stream channel realignment and restoration. The action alternative that was selected involved temporarily diverting water at an upstream location from the current channel to one of the two other braids (in the more central floodplain away from slide area) while restoring the reactivated channel as a single thread channel in a similar location to where it existed prior to Along with in-channel LWD structures and grade control to maintain the constructed energy dissipating pools, a floodplain bankfull bench was built were the current unstable channel was located. An approximate 1000 foot section of full bench temporary road was constructed to access the site with equipment. Upon project completion this access road was decommissioned with a full recontour type approach. Chapel Slide Restoration Activity Summary - Access- Constructed approximately ¼ mile of temporary road, Decommissioned after channel work was completed. - Restoration method- Relocated stream to a historic channel away from the toe of the slide, plugged unstable channel near toe, and restored new channel and floodplain dimensions. - Structure types used- Bankfull bench, rootwad revetments, debris jams, random boulder placement and cobble patches for grade control. - Restoration length- Approximately 500 feet of channel restoration. - In-channel project duration- Approximately 15 days. - Channel diversion- work would be accomplished using a clear-water diversion around the work site through the majority of the project. - Revegetation- Disturbed areas as well as newly built floodplain was planted with native species including cottonwood, conifers and miscellaneous shrubs. 1.4 Reference Reach Descriptive Information Information was gathered in similar channels with reference reach characteristics, or channel reaches with dimensions, slopes and profiles that seem to be naturally providing for long-term stability. The main reference reach utilized for the Chapel Slide project design was located directly upstream. Applicable reference reach data was compiled from a few other nearby locations and provided for a range of options. All of these reaches displayed similar channel types and substrate, as well as local slope, flow regime and bankfull characteristics. The riparian corridor within these reference locations is what is 10

12 believed the project site was like prior to the vegetation alteration and channel changing events. The table below (Table 1.2) displays the reference reach variables by site. Table 1.2 Summary of reference reach variables by site Vermilion River B3 Channel type Reference Variables West Fork Trout Creek C4 Channel Type Drainage Area (sq. miles) Bankfull Area (Riffle) Bankfull Q Width/Depth (Riffle) Entrenchment Ratio Bankfull Width (Riffle) Bankfull Mean Depth (Riffle) Bankfull Max Depth (Riffle) Bankfull Max Depth (Run) Bankfull Max Depth (Pool) Bankfull Max Depth (Glide) Average Riffle Slope Average Run Slope Average Pool Slope Average Glide Slope Run length (RL) Glide length (GL) Total Pool Length (RL+GL+PL) East Fork Bull River B3c Channel type Figure 1.6 Existing reference channel conditions above the Chapel Slide reach of the Vermilion River 11

13 Existing and Design Longitudinal Profile, Channel Dimensions The constructed project included more pool habitat and has provided for a more stable grade that will maintain the long term stability within this section of the Vermilion River. Proposed channel design characteristics such as Bankfull area (BFA), Bankfull width (BFW), Bankfull mean depth (BFDMN), Bankfull maximum depth (BFDMX) Bankfull discharge (BFQ), and Bankfull mean velocity (BFU) have been calculated for the design constructed riffle, run, pool, and glides within the project reach (see table 1.3). Design depths have taken reference reach information into account as well as local scour depth calculation at the flume locations (run locations). The calculated scour depths have taken variables such as sediment density, particle size, discharge at bankfull, gravitational acceleration, water density, run slope, run width, and fall height into account. Maximum scour depths at the run locations were approaching 6 feet in the project area under a bankfull type (1.5 yr.) flood event. These calculations have provided additional insight into how, and at what elevation footer rock and logs will be installed to ensure longterm stability. Dimension Variables Table 1.3 Summary of Design Dimensions Pre-Project Riffle (C3) Design Riffle Design Run Design Pool Design Glide Drainage Area (sq. miles) BFA BFQ (cfs) BFU (fps) Width/Depth (Riffle) Entrenchment Ratio BFW (Riffle) BFDMN (Riffle) BFDMX (Riffle) Average Slope Figure 1.7 Design planform of the Chapel Slide reach of the Vermilion River 12

14 Figure 1.8 Chapel Slide design cross section and associated shear stress values By design the floodplain construction near the toe of the slide reduced the near bank shear stress. By moving the active channel away from the slide and constructing a floodplain bench at the bankfull elevation, water velocities and associated bank stress were drastically reduced. This floodplain bench was also constructed to accept future rotational failures from the slide as the slope works toward a stable angle of repose. To date the slide has re-slid twice onto the floodplain and has not intercepted the active channel as in years prior to construction. 1.5 Hydraulics and Sediment Transport Two different entrainment calculations were evaluated using the pebble count data that was taken just above the project site (see Table 1.2). Both calculations determined the critical shear stress at a riffle during a bankfull type flood event (1.5 yr flood). The first method uses the D50 size particle of a representative pebble count, the largest particle size found on a local channel bar, the bankfull mean depth and the average slope of the riffle (Rosgen Level III field manual, 2004). The second method uses the gravitational acceleration, hydraulic radius and average slope of the riffle, and the density of water (Gordon, 1992). The entrainment results for the first equation showed particles up to the D95 size where mobile under bankfull type flows. The results for the second equation were a little more conservative and yielded particle movement up the D84 size particle during a bankfull event. Both results provided valuable 13

15 input into the design as far as the current movement of bedload through the project site directly downstream. Based on these results the cobble patch pool tail controls utilized the more conservative method and were constructed using a D95 size cobble/boulder matrix (~ mm). The table below displays the particle size distribution used within the entrainment calculations (the riffle particle size distribution just above the project area). Table 1.4 Particle size distribution above the project site Cumulative % and Finer Particle Size (mm) Riffle D16 20 D50 87 D D Restoration Activities Silt / Clay (<.062 mm) 0 % Sand ( mm) 2 % Gravel ( mm) 38 % Cobble ( mm) 44 % Boulder ( mm) 16 % Bedrock (> 2048 mm) 0 % During the month of August in 2012 approximately 500 feet of new channel was constructed through the depositional area of the local floodplain approximately 60 feet away from the toe of the slide. The historic channel location was converted back to an overbank floodplain area as what existed prior to the 1996 flood events. This restoration project created a new stream channel by utilizing upstream reference reach variables with the appropriate dimension, pattern, and profile for its specific location within the watershed. Figure 1.9 As-built channel within the Chapel Slide restoration reach of the Vermilion River one year post run-off. (Looking upstream from station 4+00). 14

16 A roughly ¼ mile stretch of roadway was built to accommodate equipment access as well as a conduit for delivering materials. This road was constructed on side slopes that exceeded 80%. Figure Temporary access road utilized for the Chapel Slide restoration. Although a permit for short-term turbidity in the Vermilion River was obtained, a temporary water diversion, located in the unstable channel at the base of the slide, routed the majority of water around the work site to limit the amount of construction related sediment increases. Culverts were installed at one location to allow for equipment access. Figure Temporary water diversion utilized for the Chapel Slide restoration. The new channel contains in-stream cobble/boulder near bank margin habitat as well as large wood to add complexity to the constructed stream channel. This placed material also provides for grade control and pool tail stabilization. All structures incorporated the final channel shaping to appropriate channel dimensions which were based on applicable local reference data. These techniques helped to protect 15

17 adjacent banks by reducing localized shear stress and positioning the thalweg in a more natural location within the reach. The constructed channel pattern was designed to allow the river to utilize as much of the valley bottom as thought feasible. By constructing a wider floodplain area for this portion of the Vermilion it was foreseen that this technique would allow for more riparian vegetation to become established as well as aid in sediment and debris transport. A total of 100 trees with attached rootballs were utilized within this project. Approximately 250 cubic yards (CY) of large angular rock was used for ballast or footer structure. Round cobble and boulder rock was imported to the site and used for grade control and habitat feature creation. As well as the imported materials, on-site resources such as the in-channel alluvium helped in the development of the new floodplain. Figure Materials stockpile at staging area and within the immediate project work site. Table 1.5 Equipment time and materials cost for the Vermilion River Chapel Slide reach restoration Item Unit Quantity Unit Price Total Fully operated excavator w/ thumb (2 machines) Hrs $ $32,643 Fully operated excavator 314 CAT (1machine) Hrs $95.00 $5,054 Fully operated CY Dump truck Hrs $80.00 $4,680 Fully operated Skidder Hrs $95.00 $3,259 Fully operated 3-5 CY Loader Hrs $ $3,623 Fully operated D5 Dozer Hrs $ $4,750 3X4X4 Assorted Angular Rock (delivered) Cubic Yards 250 $35.00 $8,750 3X4X4 Assorted Round Rock (delivered) Cubic Yards 250 $72.00 $18, ft long, diameter sound log w/ 6-10 attached rootball (delivered) Logs 100 $ $18, sorted cobble (delivered) Cubic Yards 360 $68.00 $24,480 Mobilization EA 1 $5, $5,600 Rock Blasting EA 1 $3, $3,789 Water Diversion Culverts EA 1 $ $500 Total $133,628 16

18 1.7 Riparian Revegetation During the spring and fall of 2013 stream banks through the reach were further stabilized using native seed mixes, bare root seedlings, and live vegetation stakes. Floodplain plantings consisted of Black Cottonwood, Douglas Fir, Ponderosa Pine, Woods Rose, Serviceberry, Lewis Mockorange, Thinleaf Alder, and Sandbar Willow. All disturbed areas were seeded in the fall of 2012 shortly after construction with a cover crop of Annual Rye (Lolium rigidum) and Sitka Alder (Alnus sinuata). Local topsoil was imported from adjacent floodplain areas to the site and mixed directly with the coarse alluvium at each individual planting site. To protect the vegetation from browse a fenced riparian buffer was established in strategic locations during the revegetation effort of 2013.To protect the plants from drought an extensive irrigation system was installed during the summer of Figure Riparian vegetation in the Chapel Slide reach 1 month post planting Planting Fast growing tree species were desired on this site to build deep, extensive root systems and provide future large woody debris. A diversity of species were planted in hopes to increase the chances of adequate survival. Spacing was dense to compensate for expected high mortality. Natural seedlings, particularly cottonwood, were expected to colonize the site from adjacent seed sources and in the future will be encouraged and protected as necessary. Much of the stream bank was not suitable for planting willow due to the height (2 ) above base flow level. Although willow was planted where suitable conditions existed. Shrub species suitable for the drier site conditions were planted along the stream bank. These plantings were augmented with direct seeding of native shrub species in fall Species un-palatable to ungulates were favored. A native grass seed mix was sown in fall 2012 to provide shallow soil stability and begin building organic matter. Additional seed was also used in Forest soil was collected and used in planting holes where necessary to provide additional nutrients, water holding capacity and biological associates that are beneficial to planted stock. 17

19 Planting Materials List Black Cottonwood bareroot trees on 12 x12 spacing Planting Labor- 6 days Conifer mix total, inter-planted with cottonwood Planting Labor- 2 days 25 Douglas Fir 25 Ponderosa Pine 25+ Western Larch 25+ White Pine Upland shrub seedlings- 100 Woods rose Planting Labor 3 days 100 Serviceberry 100 Lewis Mockorange 100 Snowberry Willow mix (Streambank, Sitka, Bebb, etc.) up to cuttings Planting Labor- 4 days Shrub seed Lewis Mockorange (331,250 seeds/oz.) Labor (seeding) -.5 days Snowberry (4687 seeds/oz.) Kootenai dry site and productive site native grass mixes Fencing Protection from browsing was needed for Cottonwoods and ponderosa pine. Individual cages were considered most cost effective for the planting spacing and required less maintenance. Some browsing may occur when planting stock emerges from the top of 5 cages but they should grow above browsing height the subsequent year. The need for additional protection at the 5 height will be assessed when trees reach that point. Figure Riparian vegetation fenced enclosures at the base of the Chapel slide utilized on the constructed floodplain. 18

20 Fencing Materials List Cages: 125 cages x 6.25 per cage = of 2 x4 x60 fence 8 rolls 2 6 steel T-posts/cage = 250 posts 500 fence clips Exclosure: 3 rolls fence 50 6 T-posts 150 fence clips Fencing Labor 12 days Irrigation Irrigation was considered critical to the survival of the plantings on this well drained site. A starting point watering target of 1 of water (approximately 8103 gal over 13,000ft 2 ) per week was used. Approximately 2 hours of pump run-time was needed to apply this quantity of water. Various gravity fed and drip systems were considered but due to the coarse soil texture little lateral spread of moisture from emitters was expected. To provide water to directly seeded species as well as encourage natural seedling establishment, a sprinkler system was required to distribute the water over the entire planting area. Sampling cups were used to ensure adequate water was applied at each watering. Equipment: pump and accessories Transporting materials to site ½ fire hose and fittings 14 sprinkler head assemblies Watering Labor (2013) - 11 days A combination of hand carrying, sled dragging and a rope zip-line were used to move materials down to the worksite. Zipline loads were attached to a large pulley and lowered on a 300 tensioned line. Weed Control Labor- 6 days Weeds have and will be controlled with wick (sponge) applied herbicide. Herbicide used will depend on weed species encountered. Applications will be made twice a year until trees and shrubs dominate the site. Maintenance watering 1 day/wk for 10 wks 10days/year fence adjustments and repair 3 days/year weed control 2 days/year replanting as needed 2 days/year fence removal from shrub and ponderosa pine 6 days Planning Labor- 5 days 19

21 Table 1.6 Planting, Irrigation and Maintenance Cost Summary for the Vermilion River Chapel Slide reach restoration Item Unit Quantity Unit Price Total Planting Stock EA 1 $1, $1,349 Hardware and Tools EA 1 $9, $9,793 Labor (2013 and 2014) Days 59.5 $ $7,735 Total $18, Timing, Duration and Permitting The timing of ground disturbing activities had to occur outside of the fish spawning in the Vermilion River as well as outside of high water conditions. In cooperation with Montana Fish Wildlife and parks a 124 permit was obtained with these timing restrictions set in place. Generally areas within the Lower Clark Fork notice low enough flow conditions and non-spawning windows between July 15 th and September 1 st. It took a total of 38 days between 2012 and 2013 to complete the proposed activities. Other permits such as the Corp of Engineer Nationwide 404 permit were obtained with an additional 410 wetland certification that needed completion prior to any ground disturbing activities. An application packet with all existing and proposed channel locations as well as requested design variables was submitted for review early in the spring of Project activities began shortly after the acquisition of the 404/410 permits on July 15, Table 1.7 Stream Channel Construction and Riparian Revegetation Project Duration Temporary road construction 7/15 7/19 4 days In-channel stream restoration 7/31 8/21 15 days Road Obliteration 8/22 8/26 4 days Riparian planting and Irrigation 5/28 6/21 15 days TOTAL 38 days 1.9 Water Years 2013 and 2014 Runoff Monitoring A USFS stream gaging station exists roughly 9 miles below the project reach towards the mouth of the Vermilion River. The water years of 2013 and 2014 have been represented from the calibration of discrete manual measurements and automated 30 minute data. The hydrographs are displayed below (Figures 1.15, 1.16). In 2013 and 2014 most streams in northwestern Montana experienced average runoff with the Vermilion being no exception (USFS Cabinet Ranger District 2013, USFS Cabinet Ranger District 2014). Water Year 2013 A slight spike in flow was noticed in the beginning of December 2012 that was directly linked to a mild rain event. Other peak events were captured later in the year and the hydrograph displayed flows sustaining a bankfull discharge (Q 1.5 ) of 1114 cfs for several days in May of

22 Figure Hydrograph of the Vermilion River for water year Water Year 2014 A high intensity rain on snow event occurred in the beginning of March Peakflows related to this event surpassed the bankfull discharge for approximately 5 days. The peak flow of 2014 was 1,280 cfs, which equates to the approximate 2.1 year return interval flow (Q 2.1 ). Other multiple events were captured later in the month of May 2014 and flows during this time approached but did not reach the bankfull discharge (Q 1.5 ) of 1114 cfs. Figure Hydrograph of the Vermilion River for water year

23 1.10 Dimension, Profile, Substrate and Photo Monitoring Upon completion of the construction activities in the late summer of 2012, as-built channel dimensions and profiles were surveyed within the project reach. In 2013 and 2014 this monitoring was repeated in the previous years monumented locations as well as the upstream reference reach. Photo points were also established at all monitoring sites through all survey efforts and reaches. Table 1.8 monitoring items for the Vermilion River Chapel Slide reach Monitoring Item Channel Cross Sections (Harrelson et al., 1994) Channel Longitudinal Profile (Harrelson et al., 1994) Wolman Pebble Counts (Harrelson et al., 1994) Photo Points Quantity 8 ( 3 riffles, 3 pools, 2 glides) 1 ( the entire length of the project reach, approx. 500 ft.) 4 ( 3 riffles, 1 reach) 17 (upstream and downstream of each monitored cross section and 1 pre and post construction photos) Table 1.9 monitoring items for the Vermilion River Reference reach Monitoring Item Quantity Channel Cross Sections (Harrelson et al., 1994) Channel Longitudinal Profile (Harrelson et al., 1994) Wolman Pebble Counts (Harrelson et al., 1994) Photo Points 4 ( 2 riffles, 2 pools) 1 ( the entire length of the project reach, approx. 600 ft.) 3 ( 2 riffles, 1 reach) 17 (upstream and downstream of each monitored cross section and 1 pre and post construction photos) 1.11 Project Channel Dimensions Eight channel cross-sections were measured and monumented within the project reach according to methods described by Harrelson et al To establish a range of values for each feature and encompass the majority of the project area dimensions, representative riffle, run, pool and glide units were measured immediately after project completion and two following years post run-off ( ). These results are displayed below in table 2.0 and the following graphs. Changes in the mean dimension reach variables of the project ranged from 4 to 18 percent in the first two runoff seasons. This magnitude of adjustment was expected and no transition towards an unstable channel type was occurring. A few of the monitored cross sections displayed slight aggradation while 22

24 others displayed deepening of the channel from 2012 to For example the maximum depth in cross section 5 increased from 7.87 to 8.77 feet while maintaining stable channel banks and downstream grade control. The percent change in dimension variables decreased by roughly half in the 2014 season from that noticed during the initial first runoff season of 2013 (Table 2.0). This was expected, as the first season of runoff through a newly constructed channel may have a slight adjustment period related to the settling and sealing of the grade control and bank stabilization structures. Table 1.10 Summary of monitored project dimension reach variables Dimension Variables Riffle XS#1 Pool XS#2 Glide XS#3 Riffle XS#4 Pool XS#5 Glide XS#6 Riffle XS#7 Pool XS#8 BFA (2012 As-Built) BFA (2013) Mean Reach BFA (2014) % Change in BFA ( ) % Change in BFA ( ) Width/Depth (2012 As-Built) Width/Depth (2013) Width/Depth (2014) % Change in W/D ( ) % Change in W/D ( ) Entrenchment (2012 As-Built) Entrenchment (2013) Entrenchment (2014) % Change in ER ( ) % Change in ER ( ) BFW (2012 As-Built) BFW (2013) BFW (2014) % Change in BFW ( ) % Change in BFW ( ) BFDMN (2012 As-Built) BFDMN (2013) BFDMN (2014) % Change in BFDMN ( ) % Change in BFDMN ( ) BFDMX (2012 As-Built) BFDMX (2013) BFDMX (2014) % Change in BFDMX ( ) % Change in BFDMX ( )

25 Figure 1.17 Monitored post runoff riffle cross section #1 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 24

26 Figure 1.18 Monitored post runoff riffle cross section #2 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 25

27 Figure 1.19 Monitored post runoff riffle cross section #3 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 26

28 Figure 1.20 Monitored post runoff riffle cross section #4 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 27

29 Figure 1.21 Monitored post runoff riffle cross section #5 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 28

30 Figure 1.22 Monitored post runoff riffle cross section #6 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom the pictures represent 2012, 2013 and 2014 cross section photos. 29

31 Figure 1.23 Monitored post runoff riffle cross section #7 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 30

32 Figure 1.24 Monitored post runoff riffle cross section #8 at station Within the graphs the solid line represents the bankfull elevation. From top to bottom (clockwise) the pictures represent 2012, 2013 and 2014 cross section photos. 31

33 1.12 Reference Channel Dimensions Four channel cross-sections were measured during the same time period within the reference reach upstream of the project site. To establish a range of values for specific features and encompass the majority of the project area dimensions, representative riffle, and pool units were measured in the 2014 runoff season. These results are displayed below in table 2.1 and the following graphs. Changes in the mean dimension reach variables of the reference reach ranged from 1 to 6 percent through the 2014 runoff season. This is slightly lower than what was monitored in the project reach (2 to 7 percent), but fairly similar. The magnitude of adjustment was monitored to capture the natural changes within the reference reach directly upstream of the project site. Throughout this time period there was no transition towards an unstable channel type within the reference reach. A few of the monitored cross sections displayed slight aggradation while others displayed deepening of the channel from 2013 to The riffles within the reach saw minimal change within all dimension variables. The mean and maximum depths changed slightly within the pools. This reach maintained resilient bank and bed dimensions through this runoff cycle which briefly provided for bankfull flows (Q 1.5 ). Table 1.11 Summary of monitored reference dimension reach variables Dimension Variables Pool XS#1 Riffle XS#2 Pool XS#3 Riffle XS#4 BFA (2013) BFA (2014) % Change in BFA ( ) Width/Depth (2013) Width/Depth (2014) % Change in W/D ( ) Entrenchment (2013) Entrenchment (2014) % Change in ER ( ) BFW (2013) BFW (2014) % Change in BFW ( ) BFDMN (2013) BFDMN (2014) % Change in BFDMN ( ) BFDMX (2013) BFDMX (2014) % Change in BFDMX ( ) Mean Reach 32

34 Figure 1.25 Monitored post runoff riffle cross section #1 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking downstream). 33

35 Figure 1.26 Monitored post runoff riffle cross section #2 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking downstream). 34

36 Figure 1.27 Monitored post runoff riffle cross section #3 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking upstream). 35

37 Figure 1.28 Monitored post runoff riffle cross section #4 at station Within the graphs the solid line represents the bankfull elevation. The picture represents the 2014 cross section photo (looking upstream). 36

38 Table 1.12 Comparison of Vermilion reference and Chapel Slide dimension reach variables Dimension Variables Mean Reach - Vermilion Reference ( ) Mean Reach Chapel Slide Restoration ( ) % Change in BFA 1 3 % Change in W/D 6 7 % Change in Entrenchment 3 3 % Change in BFW 3 3 % Change in BFDMN 3 5 % Change in BFDMX 1 4 Figure Dimension variable percent change within the project and reference reach through 2013 and To a certain degree natural channel fluctuations are expected within most fluvial systems. The drainages in the Lower Clark Fork are no exception. Within stable channels major shifts in channel dimension variables generally occur during low frequency high intensity flood events. These can happen at any time but are largely related to Rain On Snow (ROS) events in this area of Northwest Montana. Monitoring throughout the Lower Clark Fork region suggests flood frequencies above 10 year return interval flows could exacerbate stream channels with good stability and most likely those displaying poor stability. In general terms dimension variables that drastically change under average runoff years or bankfull type flows point to severe instability or unnatural stream channel succession. Based on the differences between the percent change within the reference and project reach, the small fluctuations in dimension variables noticed are considered acceptable. As expected the changes in reference reach dimension variables are slightly less than the project reach. This could be related to a combination of things, such as a more imbricated well developed channel and/or a more established riparian component. Over time the project reach dimension fluctuations should closer relate to those of the reference reach directly upstream. 37

39 1.13 Stream Channel Succession Reference reach information similar to that obtained for the project reach has been collected from the Cabinet and Libby Ranger Districts since Dimensionless mean values have been stratified by stream type and threshold values where channel succession is most likely to occur have been developed. The Chapel Slide restoration reach has Rosgen B/C channel types as the desired design type. The local reference derived threshold values surrounding the possible morphological changes in a C channel type are represented below in Table 2.2. Table 1.13 Vermilion stream successional threshold values derived from reference reaches within the Cabinet and Libby Ranger Districts. Dimension Variables C to B C to G C to F C to D Dimensionless W/D > 1.31 < 0.54 > 1.47 > 6.76 Dimensionless Entrenchment < 0.43 < 0.56 < 0.32 < 0.72 Dimensionless BFW/BFDMN > 1.37 < 0.57 > 1.71 > 7.26 Dimensionless BFW/BFDMX > 1.23 < 0.61 > 1.40 > 3.72 Table 1.14 Dimensionless project reach variables Dimension Variables Riffle XS#1 Pool XS#2 Glide XS#3 38 Riffle XS#4 Pool XS#5 Glide XS#6 Riffle XS#7 Pool XS#8 Mean Reach Width/Depth (2012 As-Built) Width/Depth (2013) Width/Depth (2014) Dimensionless W/D ( ) Dimensionless W/D ( ) Entrenchment (2012 As-Built) Entrenchment (2013) Entrenchment (2014) Dimensionless ER ( ) Dimensionless ER ( ) BFW (2012 As-Built) BFW (2013) BFW (2014) Dimensionless BFW ( ) Dimensionless BFW ( ) BFDMN (2012 As-Built) BFDMN (2013) BFDMN (2014) Dimensionless BFDMN ( ) Dimensionless BFDMN ( ) BFDMX (2012 As-Built) BFDMX (2013) BFDMX (2014) % Change in BFDMX ( ) % Change in BFDMX ( )

40 Should these variables be monitored through the project reach and dimensionless variables exist around 1.0, this would mean no changes were noticed and the channel is currently maintaining stability and not in a state of transition or further channel succession. Should the dimensionless variables approach the thresholds listed in table 2.2 it can be expected that channel succession is actively occurring. As table 2.3 suggests, no active channel succession is or has occurred within the project reach. In terms of channel dimensions the restoration techniques employed have proven successful in terms of maintaining a stable channel as designed that display no signs of unstable transitions through two average runoff seasons. This success in stability directly relates to near bank stress. This will allow the planted riparian vegetation to continue to flourish and add to floodplain function and bank stability Project Channel Profile The 2013 and 2014 post runoff longitudinal profiles encompassed all of the 500 feet of channel which was reconstructed in The vertical stability of the newly constructed channel can be assessed in relation to the runoff events experienced in water years 2013 and As well as sediment entrainment, the vertical stability of a reach lends inferences about vegetative potential and the static groundwater elevation in the hyporheic regions of the floodplain. Facet slopes have been measured from the 2012 as-built profile as well as the 2013 and 2014 post runoff profiles. Table 2.4 below displays the % change from as-built in terms of profile and pattern related to water years 2013 and Figure Vermilion Project Reach longitudinal profile of 2013 and

41 Table 1.15 Summary of monitored pattern and profile As-built reach variables Dimension Variables Riffles Runs Pools Glides Mean Reach Average Slope (2012 As-Built) Average Slope (2013 Post run-off) Average Slope (2014 Post run-off) % Change in Slope ( ) % Change in Slope ( ) Sinuosity (2012 As-Built) 1.08 Sinuosity (2013 Post run-off) 1.08 Sinuosity (2014 Post run-off) 1.08 % Change in Sinuosity ( ) 0 % Change in Sinuosity ( ) 0 Changes in channel elevation were noticed in certain design features. This was to be expected as the asbuilt channel went through a cleansing flow upon the first substantial run-off event post construction in None of these changes led to loss of integrity in structure or bank strength. In the more constricted areas changes led to the slight down cutting around the mid-channel boulder features (station ). These areas were constructed to constrict the channel and provide for the run type features that aide in pool maintenance and function. Although the boulder placements have not changed in elevation the margins have deepened to provide for a deeper channel. The cobble throats were designed to move under bankfull or higher flow and have slightly. These areas were further monitored through the next event cycle of 2014 and little change is occurring. Additional pool habitat formed in areas below the constructed cobble pool tails in 2013 while maintaining the same water surface elevation (station ). This is positive in terms of overall pool volume. The glide or pool tail areas seem to be sorting material as the pools have overall gotten deeper and longer. Very little deposition occurred throughout the reach. Most other changes related to the ebb and flow of natural sediment transport and did not pose any risks. Although very similar in terms of water year to that of 2013 (see figs. 1.15, 1.16) the channel bottom within the project reach seemed to have somewhat stabilized through the 2014 runoff season. Slight changes in channel features were observed. A few pools and glides deepened and further sorted a portion of the residual substrate. Riffles maintained grade. Wood structures at the lower end of the project reach seemed to have collected more material and created additional pool volume from that of the previous year. It could be expected that as long as sediment is being transported through the system some degree of channel fluctuation will occur through each runoff cycle. The descriptor that explains whether or not the channel elevation was maintained through the 2013 and 2014 flow events is the overall change in reach slope post run-off. As is displayed in table 2.4 the mean slope of the channel did not change with the 2013 or 2014 flow events and related sediment transport, nor did the planned structures create active headcutting or channel avulsions Reference Channel Profile The vertical stability of the reference channel upstream of the project site was assessed in relation to the runoff events experienced in water years 2013 and

42 Facet slopes have been measured from the 2013 and 2014 post runoff profiles within the reference reach. Table 2.5 below displays the % change in terms of profile and pattern related to water year Figure Vermilion Reference Reach longitudinal profile of 2013 and Table 1.16 Summary of monitored pattern and profile reference reach variables Dimension Variables Riffles Runs Pools Glides Mean Reach Average Slope (2013 Post run-off) Average Slope (2014 Post run-off) % Change in Slope ( ) Sinuosity (2013 Post run-off) 1.07 Sinuosity (2014 Post run-off) 1.07 % Change in Sinuosity ( ) 0 Vertical stability measured by water surface facet slopes within the reference reach changed slightly through the 2014 runoff period. All changes were within expected tolerances and very similar to changes monitored within the as-built project reach. Both reaches were subject to the same flow regime in

43 1.16 Substrate Monitoring Project Reach Wolman pebble counts were completed within 3 cross sections and the entire project reach in 2013, and repeated in 2014 following the peakflow events of both years. As-built pebble counts were not surveyed immediately after construction in 2012 as it was thought that these samples would be biased from the related instream silt. The runoff events of 2013 allowed for this minor amount of construction silt to be transported out of the project reach. Cumulative % and Finer Table 1.17 Riffle and reach particle size distribution within the project reach XS#1 (Riffle) 2013 XS#1 (Riffle) 2014 XS#4 (Riffle) 2013 XS#4 (Riffle) 2014 XS#7 (Riffle) 2013 XS#7 (Riffle) 2014 Reach 2013 Reach 2014 D D D D Silt / Clay (<.062 mm) Sand ( mm) Gravel ( mm) Cobble ( mm) Boulder ( mm) Bedrock (> 2048 mm) In terms of the channel substrate below the bankfull elevation, slight fluctuations were noticed within the riffles and the entire reach. These changes corresponded well with the minor dimension fluctuations noticed in the surveyed cross sections. A certain level of fluctuation can also be expected within this type of survey as the protocol requires random particle samples being measured in different locations each year. Substrate fluctuations of this low magnitude further support the other trends in stability throughout the project reach Substrate Monitoring Reference Reach Wolman pebble counts were completed within 2 cross sections and the entire reference reach in 2013 post runoff. These activities were replicated in 2014 following the corresponding peakflow events. Pebble counts were surveyed in 2013 and 2014 to compliment the surveys done within the project reach. Together these two data sets monitor major changes happening naturally that may influence depositional and transport functions within this area of the Vermilion River. Similar to the downstream project reach slight shifts in substrate composition have occurred in the reference reach. None of these shifts however are influencing channel function and stability of the reference or the project reach. Although still a small percentage of the total substrate composition, both the reference and project reaches noticed similar changes in the % sand within the reach. This was either associated with a seasonal flush of upstream fines, with slight deposition through both reaches, or more likely related to survey inconsistencies between the two years. The change in boulder substrate in the reference reach is likely due to survey error, as the flows through the water year were not substantial enough to transport this size of material. 42

44 Table 1.18 Riffle and reach particle size distribution within the upstream reference reach. Cumulative % and Finer XS#2 (Riffle) 2013 XS#2 (Riffle) 2014 XS#4 (Riffle) 2013 XS#4 (Riffle) 2014 Reach 2013 Reach 2014 D D D D Silt / Clay (<.062 mm) Sand ( mm) Gravel ( mm) Cobble ( mm) Boulder ( mm) Bedrock (> 2048 mm) Table 1.19 Comparison of Vermilion reference and Chapel Slide substrate reach variables Substrate Size Class Variables % Change in Silt / Clay (<.062 mm) Mean Reach - Vermilion Reference ( ) Mean Reach Chapel Slide Restoration ( ) 0 25 % Change in Sand ( mm) % Change in Gravel ( mm) 3 27 % Change in Cobble ( mm) 17 7 % Change in Boulder ( mm) % Change in Bedrock (> 2048 mm) 0 0 Figure Substrate variable percent change within the project and reference reach through 2013 and