Eagle_BasisOfDesignMemo.pdf

Eagle Canyon Fish Passage Improvements in Battle Creek

Lower and Upper Barrier Sites

Basis of Design Memorandum

February 2017

Prepared for:

California Department of Fish and Wildlife (Agreement Number D1499019)

Prepared by:

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Eagle Canyon Fish Passage Improvements in Battle Creek, Basis of Design Memorandum Page i

Eagle Canyon Fish Passage Improvements in Battle Creek, Lower and Upper Barrier Sites

Prepared for:

California Department of Fish and Wildlife Agreement Number D1499019

Prepared by:

Michael Love P.E.

Principal Engineer License No. C71681 Michael Love & Associates, Inc.

mlove@h2odesigns.com ● (707) 826-2411 x1

Travis James P.E.

Senior Project Engineer License No. C76663 Michael Love & Associates, Inc.

ptjames@h2odesigns.com ● (707) 826-2411 x5

February 2017 mailto:Mlove@h2odesigns.com mailto:ptjames@h2odesigns.com

Eagle Canyon Fish Passage Improvements in Battle Creek, Lower and Upper Barrier Sites

Page ii

Table of Contents

1 Purpose and Introduction 2 Background and Setting

2.1 Project Location

2.2 Previous Work and Relevant Studies by Others

In-Stream Flow Agreements Hydrology Studies and Streamflow Gaging Fish Passage and Fish Monitoring Studies

2.3 Summary of Previous Work Completed by MLA Design Team

Survey and Mapping Engineering Geologic Studies Characterization of Existing Hydraulic and Fish Passage Conditions Methods Alternative Analysis Construction Alternative Analysis Class 4 Cost Analysis Construction Schedule

2.4 Lower Barrier Site Summary of Existing Conditions

LBS Layout LBS Geologic Conditions and Hazards LBS Site Hydrology LBS Fish Passage Conditions

2.5 Upper Barrier Site Summary of Existing Conditions

UBS Layout UBS Geologic Conditions and Hazards UBS Site Hydrology UBS Fish Passage Conditions

3 Project Goals, Objectives, and Fish passage Design Criteria

3.1 Project Goal

3.2 Project Objectives

3.3 Fish Passage Design Criteria and Design Flows

3.4 General Fish Passage Performance Evaluation Method

4 Lower Barrier Site Project

4.1 LBS Project Description

4.2 Construction

4.3 Anticipated Fish Passage Performance

Methods Results

4.4 Expected Design Life

4.5 Anticipated Maintenance Requirements

4.6 Recommended Post-Construction Monitoring

As-Built Survey Startup Monitoring Biological Monitoring Inspection and Maintenance

4.7 Design Limitations and Uncertainties

Page iii

5 Upper Barrier Site Project

5.1 UBS Project Description

5.2 Construction

5.3 Stability Analysis of Placed Boulders

5.4 Anticipated Fish Passage Performance

Methods Results

5.5 Expected Design Life

5.6 Anticipated Maintenance Requirements

5.7 Recommended Post-Construction Monitoring

As-Built Survey Startup Monitoring Biological Monitoring Inspection and Maintenance

5.8 Design Limitations and Uncertainties

6 References

Attachments Attachment 1 – 90% Design Drawings

Attachment 2 – Annotated Bibliography of Previous Battle Creek Studies and Reports

Attachment 3 – Eagle Canyon Fish Passage Improvements; Alternative Analysis Constructability Review Memorandum (SRD, 2016a)

Attachment 4 – Eagle Canyon Fish Passage Improvements; Alternative Class 4 Estimate Narrative (SRD, 2016b)

Attachment 5 – Construction Schedule

1 PURPOSE AND INTRODUCTION

This Basis of Design Memorandum (BODM) is intended to provide a summary of the proposed fish passage improvements at the Lower Barrier Site and Upper Barrier Site in Eagle Canyon on North Fork Battle Creek near Manton, California. This memorandum provides the project goals and objectives, design criteria and decisions, description of the proposed project, anticipated fish passage conditions resulting from the project, anticipated monitoring and maintenance required, and limitations and uncertainties associated with implementation and project performance.

The information presented in this memorandum relies on previously completed work. Repeating information from other documents was minimized but some information is repeated or summarized for convenience. A discussion of previously completed documents is included in Sections 2.2 and

2.3. Descriptions and analysis presented in this BODM are based on the 90% design drawings, which are included as Attachment 1.

The organization of this BODM is as follows:

Section 2 - Background and Setting: Presents the project location, a summary of the work completed previously by others and the Design Team for this project, and a summary of the existing LBS and UBS conditions.

Section 3 - Project Goals, Objectives, and Fish Passage Design Criteria: Describes design considerations and criteria used for this project.

Section 4 - Lower Barrier Site Design: Presents the Lower Barrier Site design, including a description of the design, anticipated fish passage performance, anticipated maintenance requirements, expected design life, recommended post-construction monitoring, and design limitations and uncertainties.

Section 5 - Upper Barrier Site Design: Presents the Upper Barrier Site design, including a description of the design, anticipated fish passage performance, anticipated maintenance requirements, expected design life, recommended post-construction monitoring, and design limitations and uncertainties.

Section 6 - References: Lists reports and publications cited in this document.

2 BACKGROUND AND SETTING

Battle Creek has historically been regarded as a uniquely important watershed because of the abundance and broad diversity of Chinook salmon and steelhead that used the creek. The year-round influence of cold water springs allowed for such diversity to develop, including winter-run Chinook salmon, which are now extirpated from the watershed and in danger of extinction.

Hydroelectric facilities, operations, and other human factors likely caused the extirpation of winter-run Chinook from the Battle Creek watershed in the early 1900s (Reynolds et al. 1993).

After many years of planning, there is currently a major fisheries restoration project being completed by many organizations and led by the U.S. Bureau of Reclamation (USBR) on Battle Creek, referred to as The Battle Creek Salmon and Steelhead Restoration Project (USBR Restoration Project). Upon its completion, the goal of the USBR Restoration Project is to reestablish approximately 42 miles of prime salmon and steelhead habitat on Battle Creek, plus an additional six miles on its tributaries.

The California Department of Fish and Wildlife (CDFW) has retained the services of Michael Love & Associates, Inc. (MLA) to design and develop construction ready documents to improve upstream fish passage conditions at two natural fish barriers on North Fork Battle Creek (NFBC): Lower Barrier Site (LBS) and Upper Barrier Site (UBS). This Eagle Canyon Fish Passage Improvement Project (Project) is being completed for CDFW under Agreement Number D1499019.

The following sections present background and setting information pertinent to this memorandum.

This includes the project location, summary of previously completed work, and summaries of the existing conditions at both sites.

2.1 Project Location

This project is located within Eagle Canyon, along the border of northern Tehama and southern Shasta counties on North Fork Battle Creek (Figure 2-1). The separation between the Lower Barrier Site (LBS) and Upper Barrier Site (UBS) is approximately 1,200 feet. Eagle Canyon Dam, operated by Pacific Gas & Electric (PG&E), is located at approximately the mid-point between the two project sites. See Attachment 1, Sheet 3, for an additional site location map.

2.2 Previous Work and Relevant Studies by Others

The Battle Creek watershed has been the subject of many previous studies. An annotated bibliography of the previously completed work obtained as part of this project is included in Attachment 2. The following sections further highlight some of the studies.

In-Stream Flow Agreements In February 1999, the National Marine Fisheries Service (NMFS), U.S. Bureau of Reclamation, U.S.

Fish and Wildlife Service (USFWS), California of Department of Fish and Game (CDFG), and Pacific Gas and Electric Company (PG&E) entered into a memorandum of understanding (MOU).

The MOU outlined the roles and responsibilities regarding actions to be undertaken as part of the Battle Creek Chinook Salmon and Steelhead Restoration Project. Among other details, the MOU outlined minimum instream flow releases below various diversion dams within the anadromous reaches of North and South Fork of Battle Creek. Table 2-1 presents minimum instream flow releases at North Battle Creek Feeder Dam (Feeder Dam) and Eagle Canyon Dam by month. Figure 2-2 shows the location of these dams relative to the project sites. Currently, PG&E is operating under interim instream flow requirements.

Hydrology Studies and Streamflow Gaging Figure 2-2 presents an overview of the USBR Restoration Project components with the location of the LBS and UBS indicated. The figure also indicates the location of key dams and flow gaging stations within the watershed that may be discussed in this memorandum. MLA’s Existing Site and Hydraulic Characterization Technical Memorandum (MLA, 2016b), presents a detailed discussion of project hydrology.

Figure 2-1. Project location map.

Table 2-1. Minimum instream flow releases by month for the Feeder Dam upstream of the UBS and Eagle Canyon Dam upstream of the LBS (from the 1999 MOU).

Diversion Dam

Minimum Instream Bypass Flow (cfs)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Feeder Dam1 88 88 67 47 47 47 47 47 47 47 47 88

Eagle Canyon2 46 46 46 46 35 35 35 35 35 35 35 46

1. On occasion the release is not attainable due to the quantity of inflow reaching the dam. Additional inflows to the North Battle Creek Feeder reach are occasionally received from the junction box of the Volta 2 Powerhouse Tailrace and Cross-Country Canal a short distance downstream.

2. Eagle Canyon Dam releases reported on this table include releases from Eagle Canyon Springs (the springs located downstream of Eagle Canyon Dam).

Page 2-4

Figure 2-2. Battle Creek Schematic for USBR Restoration Project with this project's site locations and the location of various flow gages indicated.

Fish Passage and Fish Monitoring Studies There have been several fish passage and fish monitoring studies completed for Battle Creek.

The following paragraphs highlight some of these studies. Refer to MLA (2016b) for additional details.

Figure 2-3 presents a map of partial and complete natural barriers identified by Thomas R.

Payne and Associates (TRPA, 1998), with the current two project barriers indicated by the red dots. Located between LBS and UBS is Eagle Canyon Dam. TRPA (1998) identified several barriers downstream and upstream of these two barrier sites. In general, they concluded that the barriers downstream of the LBS were all passable at flows greater than 35 cfs. USFWS continues to monitor some of these barriers to determine at what flows passage is feasible.

USFWS is also monitoring locations between Eagle Canyon Dam and the UBS.

The UBS is located approximately 600 feet upstream of Eagle Canyon Dam. For reasons unknown, the 1998 TRPA fish passage assessment makes no mention of the UBS. Earley (2014) identified the UBS, referred to as Barrier B. Earley concluded that the UBS was a complete barrier at low and moderate flows, with the potential for an alternative passage route around the barrier at high flows. MLA (2016b), discussed in the following section, concluded that the primary drop is a complete barrier at all flows.

Figure 2-3. Locations of identified barriers (TRPA, 1998) with the current Project's barriers labeled by red dots.

2.3 Summary of Previous Work Completed by MLA Design Team

Work presented in this memorandum relies on work completed and documented in early documents. Many of these previous documents were included within the appendices of the Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites: Alternative Analysis Report (MLA, 2017). Table 2-2 presents the studies completed for this project by the MLA design team.

Table 2-2. A list of previously completed documents completed for this Project by the MLA Design Team.

Associated Task Document Title Primary Author Status Where

Available

Task 2

Final Eagle Canyon Fish Passage Improvement Project Task 2: Topographic Surveying and Boulder Mapping Results

Michael Love & Associates, Inc.

Final, May 2016 MLA, 2017, App. E1

Task 2 North Fork Battle Cr Eagle Canyon Survey Report

GMA Hydrology, Inc.

Final, January 2016

Task 3

Engineering Geologic Investigation Technical Memorandum Eagle Canyon Fish Passage Improvement in Battle Creek

Cotton, Shires and Associates, Inc.

Final, August 2016

MLA, 2017,

App. F1

Task 4

Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites: Existing Site and Hydraulic Characterization Technical Memorandum

Michael Love & Associates, Inc.

Final, October 2016

MLA, 2017,

App. G1

Task 5

Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites: Alternative Analysis Report

Michael Love & Associates, Inc.

Final, January 2017 MLA, 2017

Task 5

Eagle Canyon Fish Passage Improvements; Alternative Analysis Constructability Review Memorandum

SR Diversified Revision 3, October 2016

Attachment

Task 5 Eagle Canyon Fish Passage Improvements; Alternative Class 4 Estimate Narrative

SR Diversified November

Attachment

1. Indicates the Appendix the document can be found within the Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites (MLA, 2017)

Survey and Mapping GMA Hydrology’s (GMA’s) North Fork Battle Cr Eagle Canyon Survey Report (GMA, 2016) presents the work completed to develop the base topographic data for the project. This included brining control to the project sites, obtaining LiDAR data, conducting ground base scans, conducting traditional total station surveys, conducting sonar-based bathometric surveys, and obtaining low-elevation aerial photographs of the sites. Survey products included detailed point clouds, surfaces, and meshes for both sites.

MLA’s Final Eagle Canyon Fish Passage Improvement Project Task 2: Topographic Surveying and Boulder Mapping Results Technical Memorandum (MLA, 2016a) provided the results of the work completed under Task 2 by MLA. This included the labeling of boulders for both sites, mapping hydraulic control for both sites, mapping high and low flow alignments, and delivering all of the electronic information developed by both MLA and GMA.

Engineering Geologic Studies Cotton, Shires and Associates’ (CSA’s) Engineering Geologic Investigation Technical Memorandum Eagle Canyon Fish Passage Improvement in Battle Creek (CSA, 2016) provided the findings of their engineering geologic investigation. This included a rigorous investigation of the UBS and a qualitative investigation of the LBS.

Characterization of Existing Hydraulic and Fish Passage Conditions Methods The Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites: Existing Site and Hydraulic Characterization Technical Memorandum (MLA, 2016b) summarized the work and findings for characterizing existing conditions. This included field measurements (water level logger, several surveys, and time-lapse cameras) and desktop exercises (rating curves, hydraulic models, and maps) based on the field data and research. A summary of existing fish passage conditions and recommendations for the two sites are presented in Sections 2.4.4 and 2.5.4.

Alternative Analysis Based on work completed earlier, MLA scoped potential concepts to improve fish passage at the LBS and UBS. From the scoped concepts, two concepts for the LBS and three concepts for the UBS were selected for full alternative development. The concepts and alternatives were presented in Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites:

Alternative Analysis Report (MLA, 2017). The Report culminated by selecting preferred alternatives for both sites. This BODM presents additional information related to these two preferred alternatives based on the 90% Design Drawings.

Construction Alternative Analysis Based on the Draft Eagle Canyon Fish Passage Improvements in Battle Creek Lower and Upper Barrier Sites: Alternative Analysis Report (Draft Alternative Analysis Report), SR Diversified developed the Eagle Canyon Fish Passage Improvements Alternative Analysis Constructability Review Memorandum (SRD, 2016a, Attachment 3). Within this memorandum, SR Diversified conceptually analyzed large equipment access options (helicopter, crane, skyline yarder), foot and small equipment access, water control and water quality control, and rock demolition from a contractor’s point of view regarding feasibility and potential issues to overcome. MLA used this information during the development of 65% design documents.

Class 4 Cost Analysis Based on the Draft Alternative Analysis Report for the Project, SR Diversified developed the Eagle Canyon Fish Passage Improvements Alternative Class 4 Estimate Narrative (SRD, 2016b, Attachment 4). SR Diversified was directed to review three large equipment options (helicopter, crane, and skyline yarder) and develop an AACE Class 4 construction cost estimate for the two project sites. Based on the conceptual designs, the three options were found to produce similar construction costs.

Construction Schedule Based on the 65% drawings and technical specifications, SR Diversified developed a construction schedule. The first schedule developed was for a single construction season. The single construction season provided no float time, requiring everything to proceed on schedule with no unforeseen conditions arising during construction. The single season schedule also required that streamflows be low enough in June to allow installation of a stream diversion.

The schedule was viewed as too optimistic, and a two-season construction schedule was developed. The LBS will be constructed the first season and the UBS the second season.

2.4 Lower Barrier Site Summary of Existing Conditions

This section summarizes the LBS layout, geologic hazards, hydrology, and existing fish passage conditions. MLA (2016b) provides a detailed description of the LBS.

LBS Layout Figure 2-4 and Figure 2-5 presents an aerial image of the LBS and mapped boulder complexes.

Figure 2-6 presents the LBS profile. In the first two figures, water flows from right to left.

Overall, the LBS is more linear than the UBS with respect to flow direction. Flow at the LBS is concentrated on river right (looking downstream) as it passes from Pool 5, down the primary drop, into Pool 4, through Sieve B [a sieve is a gap under boulders that convey substantial flow], into Pool 3, through Sieve A, into Pool 2, and then finally into Pool 1, which marks the downstream end of the LBS reach. The water surface elevation (WSE) difference between Pools 4 and 5, which encompasses the primary drop, is approximately 8.4 feet under low flow (~35 cfs) conditions. The primary drop is approximately 34.5 feet long.

LBS Geologic Conditions and Hazards CSA (2016) conducted a qualitative geologic assessment of the LBS and Smelser (2012) conducted a more in-depth characterization of the LBS (in the channel). The two studies provide information helpful to understand the geologic hazards that exist at the LBS.

In general, the LBS is more geologically stable than the UBS but still includes some active toppling. Along the south canyon wall (river left) two very large blocks have a high failure potential and a thinner block or flake also has a high failure potential. These features are above the LBS and located within the Eagle Canyon Basalt layer adjacent to the PG&E footpaths above the LBS. The Eagle Canyon Basalt layer has pervasive, near-vertical cooling joints that result in relatively large bocks that can topple. There are other blocks and columns within this layer near the LBS, but they have a moderate failure potential (could fail within 50 – 100 years).

Figure 2-4. Aerial image of the Lower Barrier Site showing mapped boulder complexes.

Figure 2-5. Aerial image of the Lower Barrier Site taken on February 10, 2016 at a flow of 120 cfs.

Figure 2-6. Lower Barrier Site channel profile.

CSA could not access the north canyon face due to landowner access permissions, but was able to view the face from PG&E’s walkways on the south rim and from aerial photography.

The north canyon can be separated into two distinct vertical walls (referred to as upper and lower) with a sloped area between. CSA noted some detached boulders laying on the sloped area with approximately 3 feet diameters and if mobilized, they would potentially tumble into the LBS.

CSA completed field and laboratory tests to quantify the characteristics of the boulders within the channel with respect to hardness. In general, the basalt boulder strength varied from very strong (unconfined compressive strength between 14,500 and 36,250 psi) to extremely strong (unconfined compressive strength greater than 36,000 psi).

LBS Site Hydrology

Peak Flows Peak flows were estimated from the work completed by USBR (2001). The LBS peak flows are presented in Table 2-3. The flows were derived by scaling the USBR peak flows for Eagle Canyon Dam to the LBS drainage area, which is approximately 188 square miles.

Table 2-3. LBS peak flows for selected return periods.

Return Period (years) 2 2.33 5 10 25 50 100

Flow (cfs) 2,504 2,905 4,407 5,709 7,512 8,914 10,216

Daily Average Flow Duration Curves Flow duration curves are often used to determine fish passage design flows and evaluate fish passage delays due to low or high flow conditions. The annual 1% exceedance flow is often used in northern California to set the high fish passage design flow for adult anadromous salmonids (CDFG 2002; NMFS 2001).

Figure 2-7 presents flow duration curves (FDCs) constructed for the LBS. The FDC is based on daily average flow records for 16 water years collected at the BNF gage. Flows are scaled to the drainage area of the LBS. In summary, two different approaches were used to develop the FDC. The first is based on the traditional approach, which is a ranking of all of the daily average flow data to determine the exceedance flows. When applying this method, Water Year 2006 was identified as a high-flow outlier, such that eliminating this year decreased the 1% exceedance flow by 32%. Therefore, data from 2006 was excluded from the FDC, resulting in a 1% exceedance flow of 382 cfs.

Figure 2-7. Flow duration curves for Lower Barrier Site based on DWR BNF daily average flows, calculated using all data except WY2006 (outlier) and using the median of the annual flow duration curves. For 80% of the water years the annual exceedance flows will fall between the lower and upper curves.

The alternative approach used to create the FDC is based on methods outlined by Vogel and Fennessey (1994). This approach better describes annual variability and allows for calculation of annual statistics and confidence intervals. It involves constructing individual FDCs for each of the 16 water years, and then calculating the median FDC. As seen in Figure 2-7, the median 1% annual exceedance flow is 241 cfs. This means that for half of the water years, from the period of record, the 1% annual exceedance flow was less than 241 cfs and the other half was a higher. For 80% of the water years, the 1% annual exceedance flow was between 531 cfs and 138 cfs.

LBS Fish Passage Conditions MLA (2016b) concluded that the primary drop is a complete barrier to migrating salmon and steelhead. The barrier conclusion was based on field observations and two-dimensional hydraulic modeling results. The two-dimensional model results within the primary drop portion of the channel, were compared to swimming speeds based on developed equations (Hunter and Mayor, 1986) for differing fish body size and time to exhaustion for Chinook salmon. The comparison did identify that salmon in good condition could overcome the flow velocity within the primary drop prior to becoming exhausted under certain flow conditions, but the model does not capture the extreme flow turbulence that occurs throughout the primary drop.

Based on several site visits and from time-lapse photography, the turbulence within the primary drop is extreme within the primary drop and Pool 4. Therefore, although the hydraulic model and fish swimming equations may indicate that fish passage is possible, the addition of the extreme turbulence makes the primary drop a complete barrier.

2.5 Upper Barrier Site Summary of Existing Conditions

This section summarizes the UBS layout, geologic hazards, hydrology, and existing fish passage conditions. MLA (2016b) provides a detailed description of the UBS.

UBS Layout Figure 2-8 presents an aerial image and profile for the UBS. The flow is from left to right. The UBS is more complex than the LBS with respect to both flow paths and boulder arrangements. Upstream of the primary drop, flow moves through Pool 9 and then Pool 8 and then plunges over the primary drop into the shallow and fragmented Pool 7. From Pool 7, depending on flow rate, water moves through one of two sieves. One sieve connects to Pool 6 while the other travels along an unknown path that is believed to exit into Pool 6 just upstream of Pool 5. Pool 6 water, depending on flow rate, primarily flows out along two paths:

(1) to Pool 5 along the primary alignment or (2) along the secondary alignment to Pool 3.

From Pool 5 water flows into Pool 4. Flow from Pool 4 and Pool 3 meet in Pool 2; Digger Creek flow also enters Pool 2. Finally, flow moves into Pool 1, which is the downstream boundary of the UBS.

In total, thirteen sieves have been identified that convey flow under one or more large boulders. Flow in these sieves can be open-channel or pressurized, depending on streamflow conditions. The sieves complicate the flow description above. For example, several sieves move water from the secondary alignment to the primary alignment. There is also a sieve that moves water from upstream of Pool 5 along an undetermined route under boulders and discharges along the river left of Pool 4.

The primary drop is approximately 12.5 feet long and tall. The face of the drop consists of several large boulders protruding into the flow path. The lower portion of the drop is nearly vertical. The receiving pool below the drop is extremely shallow given the drop height, and a high level of turbulence is generated throughout this area.

Figure 2-8. Upper Barrier Site overview aerial image and profile. Photograph when flow within NFBC approximately 195 cfs upstream of Digger Creek.

UBS Geologic Conditions and Hazards CSA (2016) completed a robust geological investigation of the UBS. The UBS is underlain by the Eagle Canyon Basalt formation, which is characterized by a thick-bedded to massive, lightly weathered to fresh, very hard and very strong basalt.

CSA found multiple locations along the canyon walls where rock failure was either high (failure could occur at any time, but likely within 10 years), moderate to high (failure likely within 10 to 50 years), and moderate (failure likely within 50 to 100 years). The locations of the high potential failures were located at different locations along the entire UBS reach and on both sides of the channel. Many of these rockfall hazards consist of extremely large blocks of basalt.

CSA completed field and laboratory tests to quantify the characteristics of the boulders within the channel as well as the canyon walls with respect to hardness and joint characterization. The basalt boulder strength varied from very strong (unconfined compressive strength between 14,500 and 36,250 psi) to extremely strong (unconfined compressive strength greater than 36,000 psi). The rock exposed in both canyon walls is generally non-vascular basalt with a structure that varies from thin (less than 1 foot thick) to massive. The canyon rock is generally fresh to slightly weathered, with fractures that vary from widely spaced (3 feet to 10 feet) to extremely widely spaced (greater than 10 feet).

Rock joints, although infrequent, are moderately continuous (10 feet to 30 feet in length) to highly continuous (30 feet to 100 feet). Joint openings varied from tight to up to 2 inches wide and were generally open ¼ to ½ inch.

UBS Site Hydrology

Peak Flows Peak flows were estimated from work completed by USBR (2001). The UBS and Digger Creek peak flows associated with specified return periods are presented in Table 2-4. The UBS flows were derived by scaling the USBR peak flows for Feeder Dam to the UBS drainage area, which is approximately 148 square miles. The Digger Creek, with a drainage area of 40 square miles, flows were derived by subtracting Eagle Canyon Dam peak flows from UBS flows. This approach likely underestimates the actual return period flows for Digger Creek, as Digger Creek likely peaks prior to North Fork Battle Creek due to its smaller drainage area. Therefore, the data presented in Table 2-4 should be interpreted as the flow within Digger Creek at the time the UBS’ flow is peaking.

Table 2-4. UBS and Digger Creek peak flows for select return periods.

Return Period (year) 2 2.33 5 10 25 50 100

UBS Flow (cfs) 2,332 2,665 4,109 5,331 6,996 8,329 9,551

Digger Creek Flow (cfs)* 168 235 291 369 504 571 649 *Estimated using difference between Eagle Canyon Dam and UBS peak flows.

Daily Average Flow Duration Curves To assist with establishing fish passage design flows and evaluating potential low-flow and high-flow passage delays, a flow duration curve (FDC) was constructed (Figure 2-9). The FDC was created using daily average flow records from the DWR gage, BNF, scaled to the drainage area of the UBS. The first approach constructed a FDC using all of the daily average flow data sorted and ranked for the entire period of record, excluding outlier water year 2006 (similar to LBS). This resulted in a 1% exceedance flow of 293 cfs.

The second approach used to develop the FDC was constructed using the same methods described for the LBS (Section 2.4.3) and as presented in MLA (2016b). The median FDC is constructed using the median of the exceedance flows from each annual FDCs from each of the 16 water years. This means that for half of the water years, from the period of record, the 1% annual exceedance flow was less than 182 cfs and the other half was a higher. For 80% of the water years, the 1% annual exceedance flow was between 100 cfs and 410 cfs.

UBS Fish Passage Conditions Figure 2-10 provides a graphical interpretation of the fish passage conclusions for selected UBS feature. A question mark indicates that a particular bound has not been identified, but the color gradient for that feature indicates when passage may remain suitable (blue) while it moves to less than suitable (white). See MLA (2016b) for additional details.

Figure 2-9. Flow duration curves for Upper Barrier Site based on DWR BNF daily average flow record, calculated using all data except WY2006 (outlier) and using the median of each annual flow duration curve. For 80% of the water years the annual exceedance flows will fall between the lower and upper curves.

Figure 2-10. UBS fish passage conclusions for selected features (MLA, 2016b: Figure 8-18).

Based on observations, it is our opinion that passage conditions are suitable under most flows up to about 500 cfs for fish to reach Pool 6, although there is some uncertainty with respect to the conditions within Pool 5 and through Sieve D and when the secondary alignment becomes passable. Pool 6 appears to maintain favorable passage/holding conditions up to at least 500 cfs. Sieve H does appear to provide suitable passage conditions up to flows of 300 cfs, but data is lacking to quantify the upper bound for when conditions become less than suitable.

Pool 7 is undefined on both ends of the spectrum with respect to passage conditions. At low to moderate flows, the pool has insufficient depth or remains disconnected into sub-pools separated by large boulders, making in very difficult for a fish to approach the bottom of the primary drop. At higher flows the pool becomes very turbulent which may disorient fish and make holding difficult.

The primary drop appears to be a complete barrier at all flows. Passage improvements should focus passage between Pool 6 and Pool 8, including the primary drop.

3 PROJECT GOALS, OBJECTIVES, AND FISH PASSAGE DESIGN

CRITERIA

This section presents the project goal, objectives, fish passage design criteria, and fish passage design flows.

3.1 Project Goal

The project goal is to improve upstream passage for adult Chinook salmon and steelhead at the Lower Barrier Site and Upper Barrier Site located in Eagle Canyon on North Fork Battle Creek near Manton, California.

3.2 Project Objectives

The project objectives are:

• to increase water depth at low fish passage flows,

• to reduce channel velocity,

• to reduce vertical drops,

• to increase existing pools or create new pools,

• to reduce the overall slope of the channel, and

• to create variable swim paths.

3.3 Fish Passage Design Criteria and Design Flows

MLA (2016b) and MLA (2017) include robust discussions with respect to fish passage flows, and findings are summarized here. Initially, CDFW provided high and low fish passage design flows of 1,600 cfs and 35 cfs, respectively. Based on field observations and hydraulic modeling, it appears fish would be unable to migrate upstream at 1,600 cfs due to extreme velocities and turbulence occurring throughout the canyon. Therefore, the high fish passage design flow for the project was changed to the annual 1 percent exceedance flow, which is the current CDFW (CDFG, 2002) and NMFS (2001) high passage design flow criteria for Northern California for adult salmon and steelhead. Based on the flow duration curve constructed using all of the daily average flow data, but excluding outlier water year 2006, this is 382 cfs for the Lower Barrier Site and 293 cfs for the Upper Barrier Site (see Sections 2.4.3 and 2.5.3, respectively). The low fish passage design flow remains as initially set by CDFW for this project, at 35 cfs for both sites based in part on PG&E minimum instream flow requirements. The fish passage design flows are presented in Table 3-1.

MLA (2016b) and MLA (2017) also present discussions on design criteria for other parameters such as depth, velocity, and drop heights. During the development of those documents, it was not clear if the preferred alternative would be a modification or a technical fishway. Therefore, the criteria discussed included the standard criteria and guidelines from CDFW (CDFG, 2002), NMFS (2001) and NMFS (2011). Because the preferred alternatives for both sites are modifications of natural barriers, the technical fishway criteria are thought to be too stringent and alternative criteria and guidelines based on published swimming abilities of the target fish have been adopted for this project (Table 3-2). The following section presents a general discussion on how these criteria and guidelines were applied to evaluate this project’s designs.

Table 3-1. Selected fish passage design flows for the LBS and UBS.

Criteria Lower Barrier

Site Upper Barrier

Site

Low Fish Passage Design Flow 35 cfs 35 cfs

High Fish Passage Design Flow 382 cfs 293 cfs

Table 3-2. General fish passage criteria and guidelines for this project.

Fish Passage Criteria/Guidelines Value Minimum Water Depth over a feature1 0.5 ft Minimum Pool Depth 2 ft Maximum Velocity See Section 3.4

1. Such as a boulder or chute

3.4 General Fish Passage Performance Evaluation Method

This section presents a discussion on the methods used to evaluate fish passage performance for the two sites. This analysis followed the same procedures as detailed in Section 4 of MLA (2016b).

Designs for both sites included the development of an SRH-2D hydraulic model to be used for fish passage assessment purposes (as well as design development). Using the hydraulic model results, a fish routing model was developed. The hydraulic model was also used to evaluate other hydraulic conditions.

The intricacies of each SRH-2D model is discussed in each site’s relative section below and in MLA (2016b), but in general the model surfaces were developed to mimic the anticipated channel shape after construction is complete. The SRH-2D model provides a detailed simulation of the channel hydraulics covering a wide range of flows, which can in turn be used to evaluate the anticipated fish passage conditions.

A map was developed for each evaluated flow from the SRH-2D model presenting the velocity field where the depth criterion was met. Using the map, a preferred swim route was selected through the velocity field that routed the fish through the lower velocity regions that provided adequate depth (the swim path never moves in a downstream direction). The water velocities at each SRH-2D node along that swim path were then inputted into the fish locomotion and energetics model.

The fish locomotion and energetics model is based on the methods outlined by Castro-Santos (2006) to swim the fish from node to node along a selected route. The approach requires a swim speed equation for the fish, which relates time exhaustion (fatigue) for the fish when swimming at the given speed. The swimming equation used in this analysis was for burst swimming of adult Chinook salmon developed by Hunter and Mayor (1986) based on data from Weaver (1963):

𝑽𝑽𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩 = 𝟏𝟏𝟏𝟏.𝟒𝟒𝟒𝟒𝑳𝑳𝑻𝑻𝑳𝑳𝟎𝟎.𝟑𝟑𝟑𝟑𝑩𝑩−𝟎𝟎.𝟓𝟓 Equation 3-1

Where;

VBurst = Fish burst speed (m/s) LTL = Total fish length (m) t = time to exhaustion (s); such that 1 s≤ t ≤ 30 s

The time required to swim between two nodes is then calculated as a percent of the time to exhaustion at the selected swim speed. The cumulative percent of exhaustion is summed along the route. If the fish is able to swim the entire route without exceeding 100% exhaustion, then passage is successful for that fish.

For this project, the fish locomotion and energetics model swam the fish at a distance-optimizing speed. Between each node the time to exhaustion was optimized, such that the resulting swim speed of the fish minimized the fish’s physical exertion, as describe by “percent exhaustion.” The analysis was performed for varying sizes of Chinook salmon to determine the smallest fish able to successfully pass through the site.

Additional discussion specific to the LBS and the UBS are included in Sections 4.3.1 and 5.4.1, respectively. The results of the evaluations for the LBS and UBS are presented in Sections 4.3 and 5.4, respectively.

4 LOWER BARRIER SITE PROJECT

The preferred alternative for the Lower Barrier Site was Alternative B, as described in MLA (2017). The following sections present the proposed project for the LBS based on the 90% Design Drawings and Specifications. The 90% Drawings are included as Attachment 1.

4.1 LBS Project Description

The existing LBS primary drop is a narrow chute that drops into the shallow and narrow Pool

4. Boulders on the south bank and the bedrock wall on the north bank constrict both the chute and pool. The constriction creates conditions for extreme turbulence and high velocities across the entire wetted channel and throughout the water column. The extreme turbulence is likely a primary condition that blocks fish passage.

The LBS design includes removing approximately 190 cubic yards of boulders and a minor amount of bedrock. This involves removing boulders B71, B131, B72 Complex boulders and additional boulders within Pool 4 and the primary drop chute (Figure 4-1, Attachment 1). The rock will be lifted out of the canyon and disposed at the top of the canyon rim or hauled off-site. Removing the large boulders, along with some minor bedrock modification, will widen the primary drop, create multiple pathways for fish to ascend, and widen Pool 4, which will create more pool volume. Reducing the constriction and increasing the pool volume should result in less turbulence, decreased velocity, and additional holding areas for fish.

As part of the boulder removal, the design includes the creation of two new chutes (referred to as the north and south chutes) that extend upstream of Pool 4, see Attachment 1. The north chute is intended to provide a low-flow passage path; at higher flows the south chute is anticipated to have better passage conditions.

Figure 4-1. LBS Alternative B plan view of rock to be removed (yellow hatching), including B71, B131, B72 Complex boulders and some additional boulders within the Primary Drop and Pool 4.

The north chute is anticipated to be constructed within bedrock. Therefore, it is anticipated that the construction will be able to meet the design dimensions for the chute, as presented in the design drawings (Attachment 1, Sheet 11). The north chute is a trapezoidal channel with a bottom with of approximately 2 feet and a depth of at least 1 foot. The side slopes will vary.

The profile includes two grade breaks. The initial slope, extending upstream from Pool 4, is approximately 80% and 8 feet long. Although steep, it is anticipated that this lower section will be backwatered by Pool 4 under most flow conditions. The middle section of the north chute has a slope that is approximately 25% and is approximately 19 feet long. Although this is still steep, passage over similar features downstream of the LBS within Eagle Canyon exist and provide passage. The final section is approximately 11 feet long and has no slope. Field adjustments may be made based on conditions reveled during rock removal.

The south chute is shorter than the north chute but has similar design characteristics. The material comprising the south chute is unknown (boulders verses bedrock), and field adjustments may be required. The general approach is to construct the chute with a minimum

2.5 feet width and with a minimum depth of 1 foot. Like the north chute, there are two profile grade breaks. The downstream section, extending from Pool 4, has a slope of 80% and is approximately 8 feet long. The lower section is anticipated to be backwatered at most flows.

The middle section has an approximate slope of 25% and is approximately 8 feet long. The upstream section is approximately 8 feet long and has a 10% slope.

Pool 4 is anticipated to double or triple in width. This increased width will create low-velocity areas for fish to approach the primary drop and stage their attempt to move upstream.

4.2 Construction

Construction techniques are covered in detail in previously completed documents (SRD, 2016a, SRD 2016b, MLA, 2017). For reference, a summary is provided here.

Site access is extremely limited to the LBS. It is assumed that a skyline yarding system or crane (removal system) will be used to deliver materials and equipment to the site and to remove rock from the site. The lifting capabilities of such systems varies, but 8,000 lbs is a conservative estimate.

Prior to beginning the rock removal process, rockfall hazards will be mitigated. This will likely involve scaling off smaller rocks and anchoring in-place, with rock bolts, larger rocks that are at risk of falling during construction. The Engineering Geologic Investigation Technical Memorandum (CSA, 2016) provides additional rock stability details.

Rock will be removed by first drilling holes into the boulders and bedrock and then either using hydraulic rock splitters, blasting, or other techniques to break the rock into pieces that are small enough to be lifted by the removal system.

Existing trees in the stream riparian area, along the canyon walls, and up on the canyon rim will need to be removed and/or limbed to accommodate the removal system. This includes trimming the bay trees present along the south bank of Battle Creek at the LBS.

A dewatering system will be installed to bypass streamflow around the worksite. This may not need to be installed until the larger boulders that are outside of the wetted channel are removed. It is assumed that the water bypass will be installed in mid-summer when flows are close to the minimum bypass flow of 35 cfs. Materials for the dewatering system may be brought in by the removal system or by helicopter.

4.3 Anticipated Fish Passage Performance

Methods A general discussion on the methods used to evaluate potential fish passage performance within the LBS was presented in Section 3.4. As discussed there, a SRH-2D hydraulic model based on the 90% design drawings was developed and executed using a wide range of flows.

The LBS model follows the same development procedures as presented in MLA (2016b) and

MLA (2017).

Once the model runs were complete, two potential fish passage swim paths were digitized: one swim path followed the north chute and the other followed the south chute. The swim paths were routed through the lowest water velocities while having sufficient depth for passage. A fish routing spreadsheet model was then used to identify the smallest sized Chinook salmon that could swim through the velocity field without becoming exhausted based on the swim speed equations developed by Hunter and Mayor (1986). The results are presented in the next section.

Results The water surface profiles for flows from 35 cfs (low fish passage design flow) to 382 cfs (high fish passage design flow) for the LBS design are provided in Figure 4-2. To assess the change in flow conditions associated with rock removal, maps of the SRH-2D output were created for existing and proposed conditions for 35 cfs, 120 cfs 250 cfs, 382 cfs, and 1,600 cfs in Figure 4-3 through Figure 4-7. The figures show water velocities when depths are greater than 0.5 feet. The figures show that Pool 4 is substantially widened along the south side of the channel and produces a reverse circulation (back-eddy) flow pattern at all analyzed flows. It also shows that there are multiple pathways fish could use to swim up the primary drop at most flows. At 120 cfs and higher, velocities in the primary drop and flow patterns in Pool 4 suggest that fish will be able to hold in the pool and swim up the south chute while most of the turbulence and high velocities will be on the opposite side of the channel.

Table 4-1 summarizes the hydraulic conditions along the selected fish passage path at each evaluated flow. It also lists the smallest size (length) of Chinook salmon capable of swimming through the velocity field it encounters along the fish passage path.

At the low passage design flow of 35 cfs the north chute provides sufficient depth for passage, while the south chute does not. At all other flows the south chute provides sufficient depth and lower water velocities, making it the preferred passage route. At flows from 35 cfs to 250 cfs, the analysis predicts that even smaller, weaker swimming Chinook salmon could swim through the north chute and south chute, respectively. Based on the spring Chinook length data provide by USFWS for Battle Creek, 90 to 100% of the fish will be able to swim through one of the two chutes at flows between 35 cfs and 250 cfs. At the high passage design flow of

382 cfs, only the larger (top 30 percentile) Chinook salmon are predicted to have the swimming abilities to burst through the velocities in the south chute, while the north chute will be too swift for any fish to pass. This design is considered to provide passage from 35 cfs to 250 cfs, while larger salmon and steelhead will be able to pass at even higher flows.

Figure 4-2. LBS water surface profiles for the LBS proposed conditions based on SRH-2D results.

(a)

(b) Figure 4-3. LBS at 35 cfs for (a) existing and (b) proposed conditions.

(a)

Figure 4-4. LBS at 120 cfs for (a) existing and (b) proposed conditions.

(a)

Figure 4-5. LBS at 250 cfs for (a) existing and (b) proposed conditions.

(a)

Figure 4-6. LBS at 382 cfs for (a) existing and (b) proposed conditions.

(a)

Figure 4-7. LBS at 1,600 cfs for (a) existing and (b) proposed conditions.

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4.4 Expected Design Life

The LBS design is anticipated to function as constructed for an indefinite period, which could be for hundreds of years. The exact life expectancy is uncertain and dependent on future rockfall. Rockfall may occur at any time, and can be triggered by strong ground shaking from earthquakes. In most cases, maintenance in the form of rock removal could restore fish passage functionality.

4.5 Anticipated Maintenance Requirements

The LBS design will likely require little to no debris or sediment removal. There is the possibility a large log or other woody debris could become lodged between rocks in an orientation that creates undesirable passage conditions, requiring removal. This has occurred at other locations within North Fork Battle Creek.

Access for inspection and maintenance will be along the south bank of the channel. Improved site access, from the flume catwalk down to the channel, could be installed if desired and acceptable to PG&E.