Attachment A.pdf

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Campsite 8

Campsite 7

Campsite 6

Campsite 5

Campsite 4

Campsite 3

Campsite 2

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Area of Detail

Hermosa Creek Habitat Improvement ProjectRoad Crosses

Hermosa Creek

Legend !( Improvement Sites

!9 Dispersed Campsites

FS Road 578 0 500250 Feet ±

Hermosa Creek Fish Habitat Improvement Project Project Narrative

Project Overview Stream habitat for trout will be improved along a portion of upper Hermosa Creek within San Juan National Forest found in T.39N., R.10W, Secs 13, 14, and 24. The project area begins at the lower end of a low-water crossing of Hermosa Creek by Forest Road 578 in San Juan County, Colorado and extends downstream into La Plata County, Colorado for a total distance of approximately one river mile. The Hermosa Creek Fish Habitat Improvement Project has dual purposes: 1) to improve stream habitat for trout by creating pools and deeper runs that will enhance trout survival during winter and other low flow periods, and 2) to stabilize eroding stream banks at unimproved, dispersed campsites along upper Hermosa Creek.

The following types of structures and/or treatments will be used in this project: the rock cross-vane structure, the J-hook vane structure, boulder clusters, bank stabilization using native material revetment (typically boulders or a combination of boulders and logs), and relocation of thalweg (line of maximum depth in the stream channel). A brief description and design drawing of each structure type follows.

Cross-vane structure The cross-vane consists of an inverted U-shape rock structure built with boulders that extend little, if at all, above the stream invert (see Figure 2: Cross-vane structure). Boulders used for cross-vane structures in Hermosa Creek will be angular in shape and may vary from 2 ½ to 3 feet in diameter. The cross-vane is similar to the rock vortex weir, but has longer “arms” or vanes than the vortex weir and is usually placed at a lower cross-section profile within the stream channel than the vortex weir. The cross-vane structure provides grade control and narrows and deepens the stream in the center of the channel while decreasing stream power and erosion along the near bank. Sediment transport capacity is maintained by providing spaces between the boulders used in the center one-third of the channel. The cross-vane structure provides trout habitat by forming a scour pool below the structure for resting and hiding during both high flows and base flows, and by creating feeding lanes along the boundaries between fast and slow moving water. The cross-vane structure consists of a rock sill perpendicular to the stream flow located at the stream invert with two rock vanes that point downstream and that are sloped upward from the center of the channel to the bankfull height along each bank. A foundation row of boulders is buried in the stream channel to avoid undercutting and structure failure during higher flows. A centered cross-vane is constructed with the center sill occupying one-third of the bankfull width; with each of the two arms, or vanes similarly each occupying 1/3 of bankfull width. The vanes slope downstream from the sill at a 20 to 30-degree angle to the bank. An offset cross-vane structure has one longer vane and one shorter vane, and is designed to relieve shear stress on an eroded bank by shifting the flow back toward the center of the channel and away from the unstable bank.

Figure 2: Cross-vane structure. From Rosgen, 2001.

J-hook vane structure The J-hook vane is a rock structure named after its shape, and is located on the outside of stream bends to reduce bank erosion by focusing bankfull flows back toward the center of the channel.

The J-hook vane is basically a cross-vane structure with one vane removed (from the inside of the stream bend). As described by Rosgen (2001), the “hook” (or sill) portion of the structure occupies the center one-third of the channel, while the vane portion occupies one-third of the bankfull width along the outside curve of the stream channel (see Figure 3: J-hook vane structure). Boulders used for J-hook vane structures in Hermosa Creek will be angular in shape and may vary from 2 ½ to 3 feet in diameter. A foundation row of boulders is buried in the stream channel to avoid undercutting and structure failure during higher flows. The vane portion slopes downstream from the hook (or sill) at a 20 to 30 degree angle to the bank. An elongated scour pool is formed below the structure in mid-channel, serving to dissipate stream energy and providing trout habitat.

Figure 3: J-hook vane structure. From Rosgen, 2001.

Boulder cluster Boulder clusters are placed in high velocity areas to create scour pockets and habitat niches around boulders that dissipate energy and provide variable velocities favored by trout for feeding, resting, and hiding. Three to five-feet diameter boulders will be used for boulder clusters placed in Hermosa Creek. In general, boulders will be spaced 0.5 to 1 foot apart in a triangle of three boulders (see Figure 4: Boulder cluster).

Figure 4: Boulder cluster. From California Salmonid Stream Habitat Restoration Manual, 1998.

Bank stabilization using native material revetment Native material revetment is an interlocking matrix of boulders and logs that is anchored into the eroding bank of a stream to stabilize it and prevent further erosion. The purpose of native material revetment is to provide a permanent structure built with natural materials to protect eroding stream banks from the scour action of fast moving water. Micro-habitat for trout is created as a result of the edges, gaps, and voids between rocks and logs. A general example of native material revetment is shown in Figure 5. Within the Hermosa Creek Fish Habitat Improvement Project area, bank erosion is occurring at dispersed camp sites. At these campsites, stream bank access along eroded banks will be provided by incorporating two or more gently sloped terraces (2 ½ feet horizontal to 1 ft. height) using logs (with buried limbs intact) that are backfilled with stream cobble and topsoil that is found on-site. For the Hermosa Creek Fish Habitat Improvement Project, native material revetment will typically consist of a row of boulders placed in an excavated trench along the edge of the bankfull channel to provide a footer, create roughness, and dissipate the energy of water. Where additional height is needed to repair an eroding bank, a combination of rocks and/or partially buried logs will be used to create the terraced effect. For the Hermosa Creek Fish Habitat Improvement Project, dead standing trees will be harvested (with limbs intact) and used as log revetments. Dead trees can be found within the project area. Notably, there is a stand of dead spruce trees located downstream of Site 24 and Campsite 8. Dead trees are fairly accessible for removal and hauling to sites identified for native material revetment. Boulders used for native material revetment will be angular in shape and may vary from 2 ½ feet to 5 feet in diameter to create an interlocking matrix. A few boulders can be found on-site (eg. Site 16) but the majority must be imported to the project area from a rock quarry or offsite supply source.

Figure 5: Native material revetment. From California Salmonid Stream Habitat Restoration Manual, 1998 and adapted from Rosgen, 1993.

Relocation of thalweg The thalweg is defined as the line of maximum depth within a stream channel. The outside bends along the Hermosa Creek stream channel are hardened and extremely stable at several locations within the project area, being delimited by bedrock outcrops found at the edge of the valley floor at Campsites 3, 4, and 5. At these locations, the stream bed is armored with fallen rocks and large cobble and the existing thalweg is not properly located along the outside bend of the stream channel (see Figure 6: Relocation of thalweg). Relocation of the thalweg can be accomplished by use of a trackhoe to loosen and excavate cobble material to a depth of 8 to 12 inches along the outside bend of the armored stream channel (against the base of rock outcrop) and to spread the cobble along the inside bend of the stream channel at the same location. The erosive power of high flows will help to maintain and deepen the thalweg along the outside bends of Hermosa Creek where these bedrock outcrops are found after the initial stream armor is broken up and the thalweg is relocated.

Figure 6: Relocation of thalweg. Photograph is looking downstream at ST 13 showing 3 existing boulders on a rock ledge along right bank that will be moved to left bank and used for bank stabilization at Campsite 4. Armored stream cobble along the base of this rock outcrop (right bank) will also be excavated and deposited along inside bend (left bank) to relocate the thalweg to the outside bend of the channel. Computer-enhanced photo by P. Vanderbilt, 2008.

Project Schedule The Hermosa Creek Fish Habitat Improvement Project will be completed over two years in separate phases, with Phase 1 work occurring between August and October, 2011 and Phase 2 occurring between July and October, 2012. Construction of stream habitat improvement structures should be completed during the July to October period because baseflows are generally fairly stable and much lower than found during spring runoff. Forest Road 578 is not plowed in the winter and may be inaccessible from November to May. Construction of habitat improvement structures at some sites will be spread over two years and is noted in the Site Index by reference to Phase 1 or Phase 2. If no specific time reference (Phase 1 or Phase 2) is provided in the Site Index, then it is assumed that work will be completed in the first phase of the project during 2011.

Aquatic Habitat Survey An aquatic habitat survey was completed for Hermosa Creek within the project area to define the parameters of the stream habitat improvement project. A Project Map was compiled from the aquatic survey to identify specific site locations where stream habitat improvements are prescribed (see Attached Map). A Site Index was compiled from the aquatic survey to identify the parameters of the project: type of structure to be built, measurements of bankfull width, length of treatment area, and height of the streambank (where appropriate), and photographs of each site (see attached Site Index).

The following conventions were used in the habitat survey and the Site Index:

1. Numbering for stream improvement sites begins at the upstream terminus (the low water crossing of Forest Road 578) and proceeds downstream, as the water flows. Similarly, numbering for dispersed campsites and vehicle pulloffs along Forest Road 578 begins at the upstream terminus and proceeds downstream.

2. All directional references to the stream bank (right or left hand side) are made as if one is looking downstream as the water flows, -ie- river right or river left.

3. As described in the Site Index, the beginning of a treatment area (eg-bank stabilization) is always the upstream terminus and the end of a treatment area is always the downstream terminus.

The attached Site Index contains the following basic information collected at each stream habitat improvement site:

Site Number: Sites 1-24 are identified in the field with orange flagging and the Site Number shown in black lettering.

Location of structure: A GPS waypoint is marked for each site location where a structure is to be built. For sites where bank stabilization is needed, GPS waypoints mark the upper and lower terminus for treatment. For example, LBRB signifies the point where left bank rehab begins and LBRE signifies the point where left bank rehab ends.

Stream width: The stream width (measured in feet) at estimated bankfull stage for each site is provided.

Structure type: The type(s) of structure(s) to be constructed at each site is provided. Where bank stabilization is prescribed, the length of the treatment area in linear feet and average height in feet of the streambank is provided. Where relocation of thalweg is prescribed, the length of the treatment area in linear feet is provided.

Comments: Design notes and special instructions are included in the comments. Stream access notes for heavy equipment and available staging areas for delivery of boulders and other construction materials are provided.

Project Summary The Hermosa Creek Fish Habitat Improvement Project consists of constructing/installing habitat improvements at 24 sites (ST 1-ST 24) along a one-mile reach of upper Hermosa Creek in San Juan National Forest (see Table 1: Project Summary). The average bankfull stream width in this reach is 29.0 feet. Ten Cross-vane structures, four J-hook structures, three Boulder clusters, 1,056 feet of bank stabilization using Native Materials Revetment, and 556 feet of Relocation of thalweg will be completed within the Project Area during a two year time period. It is estimated this work will require a total of 700 boulders (assuming 3 feet average diameter) to be hauled to the Project area from an off-site source. Boulders must have an angular shape and average diameter = 3 feet. Boulder size may vary from 2 ½ to 5-feet diameter. It is estimated that bank revetments using rocks and logs will require 30 spruce/fir logs with length = 30 feet. Dead, standing trees will be harvested (limbs intact) within the Project area for construction of terraced log revetments. Many of these trees can be harvested from an insect-damaged stand of dead spruce trees found below Campsite 8 at the lower boundary of the Project area.

The majority of work will be completed during Phase 1 in 2011; including construction of eight Cross-vane structures, two Boulder Clusters, all bank stabilization using Native Materials Revetment, all work to Relocate the Thalweg, and the stabilization of the constructed fish barrier above the project area. Phase 2 work to be completed in 2012 includes construction of two Cross-Vane structures, four J-Hook structures, and one Boulder Cluster. Detailed information about the types and locations of structures to be constructed, design notes, and equipment access details are provided in the Site Index.

Table 1: Hermosa Creek Fish Habitat Improvement Project Summary Structure type Phase 1 (2011) Phase 2 (2012) Cross-Vanes 8 structures 2 structures J-Hook Vanes 4 structures Boulder Clusters 2 structures 1 structure Native Materials Revetment (boulders used in first or only row)

1,056 total linear feet at 11 sites

2nd row terraced rock/log revetment 500 total linear feet at 4 sites

3rd row terraced log revetment 370 total linear feet at 3 sites

Relocation of thalweg 556 total linear feet at 5 sites

Maintenance of the Fish Barrier Stabilize the sides of the constructed fish barrier.

SITE INDEX 10/24/2009

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

1 yes ST 1 21 offset Cross-Vane

Easy access for equipment via old road on west bank; rehab after ST 1 & ST2 work is completed.

Equip. access flagging is visible on right bank in Photo D. The staging area for delivery of boulders to this site is the lower end of the low water crossing of Hermosa Creek by FS Road 578.

2 yes ST 2 20.6 Boulder Cluster

Good access for equip. via ST 1 using stream corridor. Equip. access flagging is visible on west (right) bank in Photo U. The staging area for delivery of boulders to this site is the lower end of the low water crossing of Hermosa Creek by FS Road 578.

3 yes

ST 3

ST3BRB

ST3BRE

Phase 1: low profile Boulder Revetment along 38 linear feet of left bank to restore single channel

Equip. access is available directly from FS Road 578 about 80 ft from ST 3. A short access ramp will have to be constructed off FS Road 578 and rehabilitated after stream work is completed. Equip access flagging along FS Rd 578 is visible from Photo L. The staging area for delivery of boulders to this site is the lower end of the low water crossing of Hermosa Creek by FS Road 578. Boulders will be trammed with a front end loader to ST 3 via FS Road 578. Photo LBR shows left bank rehab site looking upstream.

Phase 2: J-Hook Vane

4 yes ST 4 21 Cross-Vane

Good access for equip. via pullout on FS Rd 578 and Campsite 1; rehab after ST 4, ST 5, and ST 6 work is completed. Equip. access point is flagged orange and located 20 ft upstream of ST 4 on left bank. The staging area for delivery of boulders to this site is Campsite 1, with a tight pullout from FS Road 578.

5 yes ST 5 28.5 low profile Boulder Revetment along 38 linear feet of left bank to restore single channel

Equip. access via ST 4; follow stream corridor downstream for 200 ft. The staging area for delivery of boulders to this site is Campsite 1, with a tight pullout from FS Road 578.

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

6 yes ST 6 26 Phase 2: Cross-Vane

Equip. access via ST 4 using downstream corridor for 650 ft. Boulders can be dropped off FS Rd 578 just below ST 6. The staging area for delivery of boulders to this site is Campsite 2, with a tight pullout from FS Road 578. Photo D shows ST 6 flagging and FS Rd 578 in background.

7 yes ST 7 28.5

Phase 1a: Relocation of thalweg for 124 linear feet starting just above Campsite 3.

Excavate cobble from right side and deposit it on left side to develop a new thalweg along right (outside) bank. Phase 1b: Loosen streambed cobble for 110 linear feet along base of bedrock at Campsite 3 to begin development of new thalweg along right (outside) bank. Phase 2a: Cross-Vane at leaning spruce above Campsite 3. Phase 2b: J- Hook Vane above bedrock outcrop at Campsite 3

Easy access for equipment via Campsite 3; rehab stream bank after work is completed. Orange flagging at leaning spruce tree is faintly visible in Photo U. The staging area for delivery of boulders to this site is Campsite 3, with a large pullout and parking area off FS Road 578.

8 yes ST 8 31.6 Cross-Vane for grade control (small gaps only) located immediately below bedrock outcrop.

Easy access for equip. via ST 7 using stream corridor. The staging area for delivery of boulders to this site is Campsite 3, with a large pullout and parking area off FS Road 578. In Photo U the flagging for ST 8 and ST 7 is visible.

9 yes

ST 9

ST 9BRB

ST9BRE

38.4

Bank stabilization using Native Material Revetment along 95 linear feet of left bank.

Use existing fallen log in channel and 2-3 ft.

diameter boulders delivered to site. Base row of boulders should be placed in a 6 to 12-inch excavated trench. Eroded bank height is 3 feet.

Easy access for equip. via eroded left bank at ST 9 below Campsite 3. The staging area for delivery of boulders to this site is Campsite 3, with a large pullout and parking area off FS Road 578. In Photo D the orange flagging for ST 10 is visible. In Photo U the orange flagging for ST 9 is visible.

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

10 yes ST 10 33.8 Offset Cross-Vane to keep channel on left side (as it is now).

Construction at this site is dependent on flow dynamic resulting from upstream work. Easy access for equip. via ST 9 using stream corridor.

The staging area for delivery of boulders to this site is Campsite 3, with a large pullout and parking area off FS Road 578. Photo U shows thalweg on left side of channel.

11 yes ST 11 18.9 Phase 2: centered Cross-Vane or J-Hook Vane to dissipate energy downward rather than laterally.

Stream work at this site must avoid any negative impact to FS Rd 578. Equip. access ramp should be constructed off FS Rd 578 at ST 11. Alternately, equip. access via downstream corridor from ST 9 for 320 ft. The staging area for delivery of boulders to this site is Campsite 3, with a large pullout and parking area off FS Road 578. Boulders will be trammed with a front end loader to ST 11 via FS Road 578.

12 yes ST 12 23.6 Phase 2: Boulder Cluster

Stream work at this site must avoid any negative impact to FS Rd 578. Equip. access via ST 13 using stream corridor. The staging area for delivery of boulders to this site is Campsite 4, with a pullout and parking area off FS Road 578. Boulders will be trammed with a front end loader to ST 12 via FS Road 578. FS gaging station is located 105 ft downstream from ST 12 on left bank.

13 yes

ST 13

ST13BRB

ST13BRE

27.9

Relocation of thalweg above Campsite 4 for 145 linear feet. Excavate cobble from right side and deposit it on left side to develop a new thalweg along right (outside) bank and stabilize left bank at Campsite 4. Remove 3 large boulders resting on bedrock ledge on right bank and use for stabilization of left bank at upper end of Campsite 4.

Narrow access for equip. and staging area for boulders is found at Campsite 4, due to 2 trees growing close together (about 10 feet apart) on either side of the entrance turnoff to Campsite 4 along FS road 578. One of these trees may need to be cut down to allow better access to Campsite 4 by heavy equipment. Photo LU1 was taken from Campsite 4 and shows hand-built cross-vane structure located 50 ft below ST 13. If spring runoff doesn't obliterate this structure, it should be removed with equipment to prevent further erosion to left bank at Campsite 4.

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

14 yes

ST 14

ST14BRB

ST14BRE

34.5

Phase 1a: Bank stabilization using Native Material Revetment along 120 linear feet of left bank starting at ST 14 and working downstream. Use existing fallen log in channel and 2-3 ft. diameter boulders delivered to site. Base row of boulders should be in a 6 to 12-inch excavated trench. Eroded bank height is 4 feet. Phase 1b: Relocation of thalweg for 120 linear feet to establish thalweg along right (outside) bank upstream from ST 14. Excavate cobble from right side of channel and deposit it on left side as backfill behind boulder revetment. Phase 1c:

Cross-Vane at ST 14.

Good access for equip. from eroded left bank at ST 14 and Campsite 4. The staging area for delivery of boulders to this site is Campsite 4, with a narrow pullout and parking area off FS Road 578. Photo LBRB shows left bank at beginning of bank rehab site. Photo LBRM shows left bank at middle of bank rehab site. Photo LBRE shows left bank at end of bank rehab site. Photo LU1 was taken near the downstream end of the bank rehab site looking upstream.

15 yes ST 15 25 Boulder Cluster

Good access for equip. via ST 14 and Campsite 4.

The staging area for delivery of boulders to this site is Campsite 4, with a pullout and parking area off FS Road 578.

16 yes

ST 16

ST16BRB

ST16BRE

Bank stabilization using Native Material Revetment along 70 linear feet of right bank.

Use woody material from existing mid-channel logjam along with a line of 10 to 12 large (3 to 4 ft diameter) boulders delivered to site and placed at the base of right channel. Base row of boulders should be placed in a 6 to 12-inch excavated trench. Eroded bank height is 4 feet

Equip access is via 210 ft route using stream corridor upstream from ST 17 and Campsite 5.

ROCK Photo shows existing mid-channel boulder that is a debris catcher and needs to be removed and placed along right bank just downstream of 2 limestone boulders found in mid-channel. The staging area for delivery of boulders to this site is Campsite 5, with a pullout and parking area off FS Road 578.

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

17 yes ST 17 20

Phase 1a: offset Cross-Vane located above overhanging rock ledge on right bank. Phase 1b: Relocation of thalweg for 57 linear feet by breaking up stream armor to a depth of 8 to 10 inches along/under rock ledge on right (outside) bank. Excavate cobble from right side and deposit it on left side at Campsite 5.

Backfill behind the cross-vane on left bank using cobble and construct 2 or 3 terraces with log sills to stabilize eroded left bank at Campsite 5

Good access for equip. via eroded left bank below Campsite 5 and ST 18. Alternate option to constructing a cross-vane at ST 17 is to place a large boulder against left bank above rock ledge to direct flows to outside bend (right bank). The staging area for delivery of boulders to this site is Campsite 5, with a pullout and parking area off FS Road 578.

18 yes

ST 18

ST18BRB

ST 18BRE

Phase 1a: Bank stabilization using Native Material Revetment along 130 linear feet of left bank below Campsite 5. Backfill with cobble excavated from stream channel. Base row of boulders should be placed in a 6 to 12-inch excavated trench. Eroded bank height varies from 4 to 5 feet. Use terraced logs for second row. Phase 1b: centered Cross-Vane located at beginning (upstream terminus) of left bank rehab area. Cross-vane to be built using the existing bedrock to form the right vane. Left arm of vane will be built with boulders delivered to site and will also serve to stabilize the bank on left (camp) side.

Good access for equip. via lower end of bank rehab area at ST 18 and Campsite 5. The staging area for delivery of boulders to this site is Campsite 5, with a pullout and parking area off FS Road 578. There is a good pool (3-feet deep at baseflow) existing at this location. Photo LBRB shows left bank at beginning of bank rehab site. Photo LBRM shows left bank at middle of bank rehab site. Photo LBRE shows left bank at end of bank rehab site.

19 yes

ST 19

ST19BRB

ST19BRE

Bank stabilization using Native Material Revetment along 140 linear feet of left bank, continuing where ST 18 work left off. Bank height varies from 4 to 5 feet. Base row of boulders should be placed in a 12-inch excavated trench. Use 3 to 4 feet diameter boulders to form base, with terraced logs for the second row (and possibly a third row) to achieve 5 feet bank height.

Good access for equip. via eroded bank at Campsite 5 and ST 18. The staging area for delivery of boulders to this site is Campsite 5, with a pullout and parking area off FS Road 578.

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

20 yes ST 20 26 Low profile Cross-Vane, affecting baseflows only

Equip. access via 350 ft. long route using stream corridor downstream from ST 18 and Campsite 5.

The staging area for delivery of boulders to this site is Campsite 5, with a pullout and parking area off FS Road 578. Boulders will be trammed to ST 20 using the stream corridor.

21 yes

ST 21

ST21BRB

ST21BRE

31.5

Bank stabilization using Native Material Revetment along 80 linear feet of right bank to a height of 5 to 6 feet. Use 3 to 4 feet diameter boulders to form a base row, placed in a 12-inch excavated trench. Use a second and (possibly) third row of boulders and/or logs to stabilize the 6-feet high bank at this site.

Good access for equip. via stream corridor and upper end of Campsite 6. The staging area for delivery of boulders to this site is Campsite 6, with a pullout and parking area off FS Road 578.

Campsite 6 (left bank) is visible from Photo D.

Upper end of bank rehab area has a bedrock ledge at streambed invert that is overlaid by 4 feet of eroded topsoil.

22 yes

ST 22

ST22BRB

ST22BRE

Phase 1: Bank stabilization using Native Material Revetment along 150 linear feet of left bank to a height of 4 to 6 feet. Excavate a 12-inch trench for first row of boulders. Use a second (and possibly third) row of boulders and/or log terraces to achieve 6 feet height.

Backfill with stream cobble excavated from a point bar on right bank. Phase 2: J-Hook Vane at upper end of bank stabilization area to direct flows away from left bank.

Good access for equip. via Campsite 6 and ST 22.

The staging area for delivery of boulders to this site is Campsite 6, with a pullout and parking area off FS Road 578. Photo LBRB shows left bank at beginning of bank rehab site. Photo LBRE shows end of bank rehab site.

23 yes

ST 23

ST23BRB

ST23BRE

43.4

Bank stabilization using Boulder Revetment along 120 linear feet of left bank to a height of 2 feet. Use one row of 2 to 3 feet diameter boulders for base, placed in a 6 to 12-inch excavated trench. Backfill with cobble excavated from a large, mid-channel bar.

Be careful to preserve the existing thalweg on right side of channel (as it is now). Good access for equip. via ST 23 and Campsite 7. The staging area for delivery of boulders to this site is Campsite 7, with a pullout and parking area off FS Road 578.

Hermosa Creek Fish Habitat Improvement Project

Site Orange GPS Bankfull Structure Type(s) Comments Number Flagged Waypoints Width (ft)

24 yes

ST 24

ST24BRB

ST24BRE

42.5

Phase 1: Bank stabilization using Boulder Revetment along 75 linear feet of left bank to a height of 2 feet. Use one row of 2 to 3 feet diameter boulders for base, placed in a 6 to 12-inch excavated trench. Phase 2: low profile J- Hook Vane to direct base flows only away from left bank. Located above buried log with vane in same alignment as the log.

Leave existing buried log in streambed, as it directs flows in proper direction. Good access for equip.

via ST 24 and Campsite 8. The staging area for delivery of boulders to this site is Campsite 8, with a pullout and parking area off FS Road 578. Below Campsite 8, equipment access via stream corridor is impractical due to several large logjams across the channel. Riparian vegetation is healthy and should not be disturbed. A stand of dead spruce trees found below Campsite 8 may be harvested for use as terraced log revetments at other sites within the Project area.

Average Bankfull 29.0