2012 Tatshenshini River Sonar Site Reconnaissance

BMA

PRINCE GEORGE • VANCOUVER • NANAIMO, BC • GRANDE PRAIRIE, AB • WHITEHORSE, YT www.edynamics.com This page is intentionally blank. 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

EXECUTIVE SUMMARY

The Tatshenshini River is recognized as an important spawning destination for Chinook (Oncorhynchus tshawytscha), sockeye (Oncorhynchus nerka), and coho (Oncorhynchus kisutch) salmon in northwestern B.C. A sonar reconnaissance survey was conducted in the lower reaches of the Tatshenshini River during the summer and fall of 2012, to determine if a suitable location for a sonar enumeration program could be found.

An aerial reconnaissance survey of approximately 65 km of the lower Tatshenshini River was conducted on August 6, 2012, starting approximately 6 km from the river mouth and proceeding upstream. Two candidate sonar sites were identified; these were designated sites A and B, and were revisited on August 29, 2012. Bathymetric data and physical site parameters (e.g., channel width, confinement and flow patterns) collected during the second field visit indicated that Site A was the best candidate for multi-beam sonar operation. This site is approximately 63 km upstream of the mouth of the Tatshenshini River and appears to be in a location where most of the run could be enumerated. A test of a multi-beam ARIS sonar was conducted at Site A on September 11 and 12, 2012; the test indicated that multi-beam sonar could be operated to enumerate salmon at Site A under the conditions observed during the 2012 field visits. In addition, suitable sites for a DFO field camp were identified and species apportionment of the sonar counts by drift netting appeared feasible.

The results of the 2012 program are promising; however, several significant challenges must be addressed before an operational sonar trial can be conducted. High water levels during the salmon runs in early summer, untested drift netting sites and the logistical challenges associated with accessing the site may impair the effective and safe operation of sonar at Site A. If these concerns can be addressed, development of a sonar enumeration program at Site A could proceed.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC i 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

ACKNOWLEDGEMENTS

Contributions from the following individuals were invaluable for the completion of this project. Local guides Lance Goodwin and Bob Daffe shared valuable knowledge of the lower Tatshenshini River and provided information that assisted in locating potentially suitable sonar sites. Fisheries and Oceans Canada (DFO) staff assisted with many aspects of this project: Bill Waugh assisted with the aerial reconnaissance survey, reviewed the draft report and provided much insightful information on the Tatshenshini River watershed and existing stock assessment programs. Hermann Enzenhofer (DFO) provided helpful suggestions related to sonar operation in fast flowing rivers and advised on the sonar mounts and weir configurations that could be used.

AUTHORSHIP

This report was prepared by EDI Environmental Dynamics Inc. (EDI) and B. Mercer and Associates Ltd. (BMA). The following staff contributed to this project:

Ben Snow, B.Sc., R.P.Bio (EDI)...... Primary Author, Project Biologist

Brian Mercer, B.Sc., R.P.Bio (BMA)...... Primary Editor, Contributing Author

Meighan Kearns, B.Sc., R.P.Bio, P. Biol (EDI)...... Editor

Pat Tobler, B.Sc., R.P.Bio, CPESC (EDI) ...... Review and Project Advice

Joel McFabe (EDI)...... Field Technician

David MacDonald (BMA)...... Sonar Data Review, Field Technician

Matt Power, Dipl. Tech, A.Sc.T. (EDI) ...... GIS Database, Bathymetric Mapping

Laura Grieve, B.Sc. (EDI)...... Mapping

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC ii 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

TABLE OF CONTENTS

1 INTRODUCTION ...... 1

1.1 BACKGROUND AND CONTEXT ...... 1

1.2 STUDY AREA...... 1

1.3 CHARACTERISTICS OF HIGH QUALITY SONAR SITES ...... 2

2 METHODS ...... 4

2.1 RECONNAISANCE AERIAL SURVEY ...... 4

2.2 BATHYMETRIC DATA COLLECTION...... 4

2.2.1 Field Data Collection...... 4

2.2.2 GIS Development of Bathymetric Contours ...... 5

2.2.3 GIS Development of Thalweg and Cross-section Profiles...... 5

2.3 SONAR DEPLOYMENT AND TESTING ...... 6

3 RESULTS AND DISCUSSION...... 7

3.1 RECONNAISANCE AERIAL SURVEY ...... 7

3.2 SITE DESCRIPTIONS ...... 10

3.2.1 Site A...... 10

3.2.2 Site B...... 13

3.3 BATHYMETRY...... 15

3.3.1 Site A...... 15

3.3.2 Site B...... 17

3.4 SITE SELECTION ...... 19

3.5 SONAR TESTING AND DEPLOYMENT ...... 20

3.5.1 Site Selection ...... 20

3.5.2 Echogram Interpretation...... 22

3.5.3 Deployment 1...... 23

3.5.4 Deployment 2...... 24

3.5.5 Deployment 3...... 26

3.5.6 Review of Sonar Data ...... 28

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC iii 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.6 CONSIDERATIONS FOR FUTURE PROGRAM DEVELOPMENT ...... 28

3.6.1 Run Timing and Stock Composition ...... 29

3.6.2 Tatshenshini River Water Level Fluctuations...... 33

3.6.3 Equipment Requirements ...... 37

3.6.4 Species Apportionment ...... 40

3.6.5 Logistical Considerations...... 40

4 CONCLUSIONS...... 41

5 REFERENCES...... 42

5.1 PERSONAL COMMUNICATIONS ...... 42

5.2 CITATIONS ...... 42

5.3 SPATIAL DATA...... 43

LIST OF FIGURES

Figure 1: Overview of the Tatshenshini River Study Area...... 3

Figure 2: Tatshenshini River Candidate Sonar Sites...... 9

Figure 3: Bathymetric map of Site A...... 16

Figure 4: Bathymetric Map of Site B...... 18

Figure 5: Test deployment locations of ARIS Sonar at Site A...... 21

Figure 6: Example of an echogram produced from ARIS sonar data, using the DIDSON Control and Display Software...... 22

Figure 7: Deployment 1 echogram...... 24

Figure 8: Deployment 2 echogram...... 26

Figure 9: Deployment 3 echogram...... 28

Figure 10: Comparison of catch-per-unit-effort (CPUE) of sockeye salmon and radio tags applied on the lower Alsek River, 2001 – 2003. (Chart Source: Smith et. al. 2009)...... 30

Figure 11: Chinook and sockeye salmon catches in a 13.5 cm mesh gillnet on the lower Alsek River, 2002 (Chart Source: Pahlke and Waugh 2003)...... 31

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC iv 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Figure 12: Distribution (and 95% C.I.) of radio tagged sockeye salmon, by stock group, in major spawning areas of the Alsek-Tatshenshini rivers, 2001 – 2003. Stock groups are ranked in ascending order (left to right), by distance upstream from tidewater. Sonar Site A is located between Lower and Upper Tatshenshini groups (Chart Source: Smith et al. 2009)...... 32

Figure 13: Distribution (and 95% C.I.) of radio tagged Chinook salmon, by stock group, distributed in major spawning areas within the Alsek-Tatshenshini system, 1998 and 2002. Stock groups are ranked in ascending order (left to right), by distance upstream from tidewater. Sonar Site A is located downstream of the Low Fog stock group. (Chart Source: Pahlke and Waugh 2003)...... 33

Figure 14: Summary of Tatshenshini River historical discharge data from June to October, 1989 to 2011, as measured at WSC gauging station 08AC002 near Dalton Post (Data Source: Environment Canada 2012b)...... 35

LIST OF PHOTOS

Photo 1: View of the Tatshenshini River near the O’Connor River confluence, with a large number of braided channels, August 6, 2012...... 7

Photo 2: View of the Tatshenshini River near the downstream end of the survey area, showing turbulent flow in the foreground, August 6, 2012...... 8

Photo 3: Upstream view of Site A, showing the narrow, confined, single-thread channel, August 6, 2012... 10

Photo 4: Downstream view of Site A from upstream gravel bar, showing steepness of surrounding terrain, August 6, 2012...... 11

Photo 5: Downstream view of Site A, note the small area of turbulent water in the foreground, August 29, 2012...... 11

Photo 6: Upstream view of Site A, showing the relatively laminar flow pattern present through most of the site, August 29, 2012...... 12

Photo 7: View of the left bank of Site A, showing heavily vegetated, steep banks, August 29, 2012...... 12

Photo 8: Downstream view of Site B, showing the narrow area mid-site, August 6, 2012...... 13

Photo 9: Upstream view of Site B, showing the gravel/cobble shoreline on the right bank, August 6, 2012...... 14

Photo 10: View of the left bank of Site B, showing turbulent flow, September 12, 2012...... 14

Photo 11: View of the ARIS sonar and mount at Deployment 1, note the turbulent flow present mid- channel, September 11, 2012. The red arrow indicates the direction of insonification...... 23

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC v 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 12: View of the ARIS transducer and mount, installed at Deployment 2, September 12, 2012. The red arrow indicates the direction of insonification...... 25

Photo 13: View of the ARIS transducer and mount installed at Deployment 3, September 12, 2012. The red arrow indicates the direction of insonification...... 27

Photo 14: View of the left bank of Site A, showing evidence of bank scour during high flow, September 11, 2012...... 36

Photo 15: View of a large, uprooted tree on the gravel bar upstream of Site A, September 11, 2012...... 37

Photo 16: View of a ladder type sonar mount installed instream. Photo provided by H. Enzenhofer, 2012. 38

Photo 17: View of a sectional, deep-water, aluminum weir installed on the Chilko River, B.C. Photo provided by H. Enzenhofer, 2012...... 39

Photo 18: View of a deep-water steel tripod weir installed on the Big Salmon River, Yukon. BMA Photo, 2012...... 39

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC vi 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

1 INTRODUCTION

1.1 BACKGROUND AND CONTEXT

The Tatshenshini River drains a large area of southwestern Yukon and northeastern B.C. and flows into the Alsek River, in Alaska (Figure 1). Salmon in the Alsek/Tatshenshini drainage are jointly monitored and managed by Alaska Department of Fish and Game (ADF&G) and Fisheries and Oceans Canada (DFO). The Tatshenshini River is known to be a major spawning destination for Chinook (Oncorhynchus tshawytscha), coho (Oncorhynchus kisutch) and sockeye (Oncorhynchus nerka) salmon; spawning in this river supports important subsistence, first nation, commercial and recreational salmon fisheries in both Canada and the U.S.

Chinook and sockeye are the primary species of interest for fisheries managers, and spawning escapement of these two species into the Tatshenshini River is monitored by DFO. Chinook salmon abundance in the system has been estimated via mark-recapture programs, catch monitoring, a counting weir on the Klukshu River and aerial surveys of the Blanchard River, Takhanne River, and Goat Creek. Sockeye salmon abundance has been monitored via mark-recapture estimates, catch monitoring, and escapement enumerations at the Klukshu River weir and the Village Creek electronic counting station.

The existing stock assessment programs are the Klukshu River weir and the Village Creek electronic counting station located in headwater tributary streams of the Tatshenshini River, over 150 km from the river mouth. Estimates of drainage wide abundance for both species is estimated from the expansion of weir counts using stock proportions obtained from genetic stock identification (GSI) sampling.

DFO is currently investigating the feasibility of developing a sonar enumeration program on the Tatshenshini River. This program could count a larger proportion of the total Chinook and sockeye salmon stocks, and could potentially count coho salmon (if warranted). A sonar deployment downstream of existing stock assessment sites could provide a cost-effective and accurate escapement estimate for Chinook and sockeye salmon in the Tatshenshini River watershed as well as timely in-season indices of spawning salmon abundance.

EDI Environmental Dynamics Inc. (EDI) and B. Mercer and Associates Ltd. (BMA) were retained by DFO to determine if a suitable location for sonar enumeration of Chinook and sockeye salmon could be found on the lower Tatshenshini River.

1.2 STUDY AREA

The study area extended from the confluence of the Alsek and Tatshenshini rivers upstream to the mouth of Low Fog Creek, a river distance of approximately 65 km (Figure 1). The portion of the river between the mouth of the O’Connor River and Low Fog Creek (Figure 1) was not included in the original proposed survey area; however, this area was included during the reconnaissance survey to increase the chances of finding a suitable site.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 1 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

1.3 CHARACTERISTICS OF HIGH QUALITY SONAR SITES

High quality sonar sites possess several common characteristics. Accordingly, EDI and BMA searched for a sonar site on the Tatshenshini River with the following characteristics:

 A single thread, unbraided channel, free of obstructions;  A bathymetric profile with an smooth, even and consistent slope from each shore to the thalweg (i.e. absence of instream obstructions such as submerged boulders);  Near laminar flow pattern;  Stable river banks and bed (e.g. cobble material);  Absence of eddies or slow moving water that could encourage fish holding or milling behavior;  A location near the sonar deployment site suitable for the establishment of a permanent DFO field camp, to be accessed and provisioned by boat or air.

There is considerable overlap of Chinook, sockeye and coho returning to the Tatshenshini system; therefore, a means species apportionment of the sonar count is required. The site search also sought a location where drift netting (using gillnets) could be conducted near the sonar deployment location in order to apportion sonar counts.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 2

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Path: J:\Yukon\Projects\2012\12_Y_0319_DFO_Alsek_Tat_Sonar_Recon\Mapping\Figure1_OverviewMap_Alsek_Tatshenshini.mxd 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

2 METHODS

Three helicopter based field trips were conducted to locate, investigate and test the operation of sonar on the Tatshenshini River. The primary objective of each trip is listed chronologically below:

1) A reconnaissance aerial survey to locate suitable sonar sites on the lower Tatshenshini River (August 6, 2012); 2) Bathymetric data collection at each candidate site (August 29, 2012); and, 3) Deployment and testing of multi-beam sonar at the highest quality candidate site (September 11 – 12, 2012).

A secondary objective during all field trips was to document river conditions at different discharges levels. The methods used, and data parameters collected during each field visit, are summarized in the sections below.

2.1 RECONNAISANCE AERIAL SURVEY

Prior to the reconnaissance aerial survey, the study team reviewed available air photos with DFO staff and identified several narrow, single thread channels within the study area. A field crew consisting of an EDI project biologist, a BMA sonar advisor and a DFO stock assessment biologist conducted the reconnaissance aerial survey of the Tatshenshini River on August 6, 2012. Sites identified during pre-field mapping exercises were investigated, as were a number of additional sites identified in the field. As noted in Section 1.3, this initial search focused on sites with the following characteristics:

 Narrow single-thread channel;  Laminar flow pattern;  Absence of instream bars, submerged rocks or other instream obstructions;  Stable stream banks;  Potential field camp and drift netting locations nearby.

Sites possessing the desired characteristics were examined from the air; the field crew also landed at the nearest possible location and examined the sites from the ground. Photographs and UTM coordinates were recorded at each site. High definition video was conducted to document the flow patterns and general site conditions; video was recorded on the ground and as well as from the helicopter.

2.2 BATHYMETRIC DATA COLLECTION

2.2.1 Field Data Collection

Based on the results of the reconnaissance survey, bathymetric data was collected at two candidate sites on August 29, 2012. The first site (Site B) was located approximately 13 km upstream of the mouth of the

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 4 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Tatsheshini River, and the second sited was located 50 km further upstream (Site A). Additional photos, high definition video and detailed field notes were also collected at this time.

An EDI field technician collected bathymetric data using a Garmin 421S chartplotter mounted on a 14 foot inflatable Zodiac boat. Bathymetric data was collected over approximately 100 m of river channel at each candidate site. Point features representing water depths were collected using the chartplotter. At the outset of point/depth collection, a systematic approach (i.e., grid) was applied; however, stream current, shallow water and other stream characteristics did not allow for uniformity. In addition, unsafe conditions at some locations made shoreline data collection difficult or impossible. A large number of point features were collected at each site, to help compensate for the challenges described above. This data was stored on the internal memory of the chartplotter device and exported to ArcGIS upon return to the office. Bathymetric maps were subsequently developed for each candidate site.

2.2.2 GIS Development of Bathymetric Contours

The shoreline was delineated manually with ArcGIS Desktop, using hand-drawn maps and descriptive field notes to create a polyline that represents uniform shoreline. This process adds a level of uncertainty (±2 metres1) to the bathymetric contouring, specifically in locations close to shore.

Following shoreline delineation, point/depth data was brought into an ArcGIS v.10.1 workspace along with the polyline depicting the shoreline. The polyline was converted to points, which then were merged with the point/depth data and given a depth value of 0.00. Using ESRI ArcGIS extension, 3D Analyst, a triangular irregular network (TIN) was created to represent the surface of the stream bed in a three- dimensional sense. The TIN allows elevation values to be interpolated at locations between points and is required to interpret z-axis values (i.e. depth) for the creation of bathymetric contours.

Bathymetric contours were generated with an elevation interval of 0.25 m, using the TIN as the surface input. The Surface Contour tool in 3D Analyst was employed to create the contours. The resulting contours were then smoothed to better represent a natural stream profile.

2.2.3 GIS Development of Thalweg and Cross-section Profiles

The thalweg and cross-sectional profiles of the river were derived by linear interpolation of the surface TIN data using Arc Extension 3D Analyst within an ArcGIS workspace. Graphic lines were drawn over areas on the TIN where the thalweg and profiles were to be extracted. With a line selected, a two dimensional graph was automatically produced using a quick-command tool (Interpolate Line) in 3D Analyst. This tool automatically interpolates elevations of the TIN that intersect with the line and generates a graph within the workspace display. This provides an approximation of the cross sectional profiles of the river channel in the area of interest. The widths of the cross sections derived using ArcGIS are narrower than the field measured

1 Shoreline represents the 0.00 m mark for bathymetric data, and may skew interpolated depths when not collected in the field or delineated using an adequate source (i.e. orthophoto, satellite imagery). An adequate source was not available for the sonar candidate sites. Also, streams are very dynamic and glacier fed systems have increased depth variability.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 5 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT channel widths, as the zodiac could not be operated in the shallowest areas of the channel adjacent to the shore.

2.3 SONAR DEPLOYMENT AND TESTING

The third site visit was conducted by the EDI project biologist and BMA sonar technician September 11 to 12, 2012. An Adaptive Resolution Imaging Sonar (ARIS) was deployed at the highest quality candidate site. ARIS is a multi-beam sonar system manufactured by Sound Metrics Corporation that uses up to 128 sonar beams to deliver real-time video of acoustic targets.

The ARIS was deployed and tested at three locations within each candidate site. It was installed on a steel mount and set to record all data. Test deployment sites were accessed by means of a 14 foot inflatable Zodiac boat. Sonar data was recorded on a laptop. A portable 1000 watt generator provided the necessary power for the sonar and laptop.

At each site, the distance from the transducer to the high water mark was measured with a laser range finder or meter tape, UTM coordinates were recorded and photographs were collected. Water turbidity was measured September 11, 2012. The field crew also recorded detailed notes on the river morphology and bank characteristics at each candidate site.

At each deployment site, the field crew attempted to determine if the entire water column was insonified (i.e. completely covered by the sound energy produced by the sonar). This was accomplished by drifting the boat and/or walking through the sonar beam. In some areas, objects (e.g. a boat paddle), were used to determine if the deeper portions of the water column were being insonified. Sonar data was reviewed by a BMA technician to determine if any fish had passed during the test period.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 6 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3 RESULTS AND DISCUSSION

3.1 RECONNAISANCE AERIAL SURVEY

The majority of the study area was unsuitable for sonar deployment. In most areas, the river was very wide and braided; multiple small channel and unconfined reaches were present (Photo 1). This type of channel morphology is too wide to insonify effectively. Other sections of the river were removed from consideration due to very turbulent flow (Photo 2), which would introduce an unacceptable amount of background noise into sonar data. However, areas of relatively confined, narrow channel were identified; two candidate sites were selected within these areas during the reconnaissance survey on August 6, 2012 (Figure 2). The first candidate site (Site A) was located approximately 3.5 km downstream of the mouth of Low Fog Creek (approximately 63 km upstream of the Tatshenshini/Alsek River confluence). The second candidate site (Site B) was located 13 km upstream from the confluence of the Tatshenshini and Alsek rivers. The suitability of these two sites was further examined in the subsequent ground surveys.

Photo 1: View of the Tatshenshini River near the O’Connor River confluence, with a large number of braided channels, August 6, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 7 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 2: View of the Tatshenshini River near the downstream end of the survey area, showing turbulent flow in the foreground, August 6, 2012.

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R I V E R T o w a K M g S E h A L e

l t Cre ek T owa gh G la Project Specific Features Yukon c Figure 2. Tatshenshini River i e H r a British Columbia i n e Candidate Sonar Sites s Candidate Sonar Site T

Map Area t s H

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Data sources h e i Yukon topographic spatial data provided by Geomatics - Yukon Government via k n i

online source (Corporate Spatial Warehouse) www.geomaticsyukon.ca. R

. General Map Features B R r . Project specific features were derived / digitized by EDI Environmental Dynamics it is Inc. (2012). h C Trail A o This document is not an official land survey and the spatial data presented is la lu s m subject to change. k a b Secondary Road ia

Highway 0 2 4 6 8 10

Contours Kilometres

Map Scale 1:200,000 (printed on 11 x 17) Watercourse Map Projection: North American Datum 1983 UTM Zone 7N

Watercourse Drawn: Checked: LG / MP BSn / MP Date: 12/14/2012 FIGURE 2

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3.2 SITE DESCRIPTIONS

Descriptions of the physical parameters of each site (e.g. channel morphology, flow patterns, surrounding topography) are described in the sections below. By convention, the right and left banks refer to the orientations to the observer when facing downstream.

3.2.1 Site A

Site A was described as a narrow, confined, single-thread channel located downstream of a large gravel bar. The site was approximately 200 m in length and 40 - 50 m in channel width (Photo 3). The surrounding area was mountainous, and the elevation of the terrain increased quickly from both river banks (Photo 4). At the time of the field visits, a small area of turbulent water was noted at the upstream end of the site (Photo 5); however, the remainder of the site had relatively fast-flowing, laminar flow conditions (Photo 6). No instream bars, boulders or other channel obstructions were observed.

The river banks in this area were steep to vertical and heavily vegetated (Photo 7). Both the river bed and banks were comprised primarily of cobbles. Considerable amounts of clumped small and large woody debris were present on the both banks (Photo 7).

Potential camp locations are present on small benches above both banks. A potentially suitable drift netting location is present downstream of the site. No suitable helicopter landing sites were located within the site itself; a large gravel bar immediately upstream of the site was the nearest suitable landing site.

Photo 3: Upstream view of Site A, showing the narrow, confined, single-thread channel, August 6, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 10 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 4: Downstream view of Site A from upstream gravel bar, showing steepness of surrounding terrain, August 6, 2012.

Photo 5: Downstream view of Site A, note the small area of turbulent water in the foreground, August 29, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 11 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 6: Upstream view of Site A, showing the relatively laminar flow pattern present through most of the site, August 29, 2012.

Photo 7: View of the left bank of Site A, showing heavily vegetated, steep banks, August 29, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 12 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.2.2 Site B

Site B, a short, confined and narrow section of river on a bend (Photo 8), was approximately 150 m in length and 60 m wide. A large bedrock bluff was present on the left bank near the downstream end of the site, on the outside of the river bend (Photo 8). A gently sloping gravel/cobble shoreline was present on the right bank (Photo 9). No instream bars, boulders or other channel obstructions were noted in the reconnaissance survey of this site; however, given the turbulent flow and the nearby bedrock outcrop, boulders may be present in deeper areas of the site.

Above the left bank, the terrain was steep; in contrast, the terrain above the right bank was flat. Compared to Site A, the flow is more turbulent, especially in the upstream part of the site (Photo 10). Minimal amounts of woody debris were present on the banks and the shoreline areas were free of vegetative growth.

A potential camp location was identified on the flat terrain above the right bank. A potentially suitable drift netting location was also identified downstream of the site. A suitable helicopter landing area was present on the right bank at the time of the field visit.

Photo 8: Downstream view of Site B, showing the narrow area mid-site, August 6, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 13 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 9: Upstream view of Site B, showing the gravel/cobble shoreline on the right bank, August 6, 2012.

Photo 10: View of the left bank of Site B, showing turbulent flow, September 12, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 14 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.3 BATHYMETRY

Bathymetric data collected at Sites A and B are shown in Figure 3 and Figure 4, respectively, and are described in the sections below.

3.3.1 Site A

The thalweg at Site A was situated mid-channel at the upstream end of the site, migrating to and from the right bank further downstream (Figure 3). The deepest area of the channel was approximately 3.75 m (based on bathymetric coutours at the upstream end of the site); the thalweg was generally shallower in the downstream direction. In general, the river bed sloped at a shallow angle from the wetted edge of the left bank to the thalweg near the right bank. The slope from the wetted edge of the right bank was generally steeper. Near the downstream end of the site, the channel widened and the river became shallower. In the downstream end, the slope of the river bed was flatter and small rises (e.g. instream gravel bars) were present. In regards to sonar operation, the most favorable bottom profiles at Site A were present in the narrower sections mid-site.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 15 708600 708700 ³ 0 0 0 0 0 0 1 1 3 3 6 6 6 6 0 0 0 0 9 9 0 0 3 3 6 6 6 6

m Direction of flow 0 0 4

m 0 Right Bank 0 4 Left Bank 0 0 0 0 8 8 0 0 3 3 6 6 6 6

Legend Yukon * Figure 3. Bathymetric Map Sonar Deployment Site British Columbia

H of Site A a Shoreline in

T e

t s

Thalweg (estimated) A h H

l e i s g Data Sources n h e Site A s w Topographic Spatial Data courtesy of Her Majesty the Queen in Right of Canada, k Bathymetric contour (0.25 m interval) h a

r R Topographic contour (1:50,000) it R . is . Digital Elevation Model provided by Geomatics Yukon - Yukon Government via h * arrow indicates the direction of insonification online source (Corporate Spatial Warehouse) www.geomaticsyukon.ca. C o A l la u Project data displayed is site specific. Project specific data were derived / s m Depth (m) digitized by EDI Environmental Dynamics Inc. (2012). k b a ia 0.00 to -0.25 -1.76 to -2.00 Disclaimer This document is not an official land survey and the spatial data presented is -0.26 to -0.50 -2.01 to -2.25 subject to change.

-0.51 to -0.75 -2.26 to -2.50 0 10 20 30 40 50 -0.76 to -1.00 -2.51 to -2.75 Meters

-1.01 to -1.25 -2.76 to -3.00 Map Scale 1:1,000 (printed on 11 x 17) Map Projection: North American Datum 1983 UTM Zone 7N -1.26 to -1.50 -3.01 to -3.25 Drawn: Checked: Date: 12/14/2012 -1.51 to -1.75 -3.26 LG / MP BSn / MP FIGURE 3

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3.3.2 Site B

At Site B, the thalweg was near the left bank throughout most of the upstream and middle portion of the site (Figure 4). The deepest area of the channel was approximately 6.3 m (based on contours depths); in general, the thalweg exceeds 5 m in the upstream and middle portions of the site. The slope of the river bottom from the left bank to the thalweg is steep through the length of the site; conversely, the slope from the right bank is much shallower. A rise is present on the right bank, near the downstream end of the channel constriction (rising from 1.05 m to 0.5 m). This rise is small; however, and could be avoided if required.

Near the downstream end of the site, the channel widens, the river becomes much shallower and a submerged, mid-channel bar can be seen from the bathymetric data collected in this area. The bathymetry of this part of the site is unsuitable to sonar operation. For the purposes of sonar operation, the most favorable bathymetry at Site B is in the middle of the site, where the channel is narrowest.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 17 695600 695700 695800 0 0 0 0 7 7 5 5 9 9 5 5 6 ³ 6 0 0 0 0 6 6 5 5 9 9 5 5 6 6

Right Bank Left Bank 0 0

0 Direction of flow 0 5 5 5 5 9 9 5 5 6 6

200m

Yukon Legend Figure 4. Bathymetric Map Shoreline British Columbia H

of Site B T a i

a n e t s

Thalweg (estimated) s h

A e H l n s i

Bathymetric contour (0.25 m interval) Data Sources s g e h

r R i .

t . is Digital Elevation Model provided by Geomatics Yukon - Yukon Government via h Depth (m) online source (Corporate Spatial Warehouse) www.geomaticsyukon.ca. A C la o s lu Project data displayed is site specific. Project specific data were derived / k m a 0.00 to 0.50 -3.51 to -4.00 digitized by EDI Environmental Dynamics Inc. (2012). b ia -0.51 to -1.00 -4.01 to -4.50 Disclaimer This document is not an official land survey and the spatial data presented is Site B -1.01 to -1.50 -4.51 to -5.00 subject to change.

-1.51 to -2.00 -5.01 to -5.50 0 10 20 30 40 50

-2.01 to -2.50 -5.51 to -6.00 Meters -2.51 to -3.00 -6.01 to -6.50 Map Scale 1:1,000 (printed on 11 x 17) Map Projection: North American Datum 1983 UTM Zone 7N -3.01 to -3.50 -6.51 Drawn: Checked: Date: 12/14/2012 LG / MP BSn / MP FIGURE 4

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3.4 SITE SELECTION

Based on the physical parameters (Section 3.2.1) and bathymetric data, it was determined that Site A was the best candidate site for a sonar system. Site A was selected over Site B for many reasons, including: bathymetry, flow patterns, channel confinement and logistical requirements, discussed below. Suitable sites for drift netting and a field camp were also identified near Site A.

The bathymetric profiles of both Sites A and B indicate that a suitable site for the deployment of sonar could be found. However, the possible presence of submerged boulders at Site B adds considerable uncertainty to the bathymetry of this site. Boulders and other submerged instream obstacles can create blind spots within the sonar image, which can lead to fish passing through the sonar beam undetected. At Site A, the relatively laminar flow and lack of nearby source material (e.g. bedrock outcrops) for boulders suggests that the likelihood of encountering instream boulders is much lower than at Site B.

The more laminar flow pattern observed at Site A is more favorable than the more turbulent flow at Site B. Turbulent flow typically results in a larger amount of air bubbles within the water column. These bubbles can scatter a large amount of acoustic energy and reduce the signal-to-noise ratio, resulting in a poor sonar image.

The degree of channel confinement is an important indicator of river bank and bed stability; a more confined channel will likely result in a more stable site. The rock bluff at Site B confined the channel on the left bank; however, the right bank slope was flatter and the channel less confined. In contrast, the channel at Site A was confined by steep banks on both sides. Site A likely has the more stable channel.

From a logistical point of view, Site A is approximately 50 km closer to road access at Dalton Post than Site B; it is approximately 20 minutes closer by helicopter to Dalton Post and likely several hours closer by boat. Therefore, Site A would be easier to access and logistically more cost effective.

Field camp and drift netting sites appear to be slightly better at Site A. A field camp could be constructed at Site B, but would need to be located some distance away from shore on the right bank. At Site A, a field camp could be installed above either bank and would be closer to the sonar deployment. A long straight reach downstream of Site A appeared to be suitable for drift netting. A potential drift netting site was present downstream of Site B; however, it was less ideal, as it was on a bend and the river current was stronger. The river widened downstream of both sites, which is favourable for drift netting. It is important to note that drift netting should be tested to confirm.

One advantage of Site B relates to fisheries management objectives for the Tatshenshini River. Site B is 50 km further downstream than Site A. A larger proportion of the total sockeye run passes Site B. Sockeye radio telemetry studies conducted over the period 2001 - 2003 indicated the 38.4% (range 25.3% – 43.1%; s.d. = 7.5) of the total Alsek-Tatshenshini run spawns below Site A, and approximately half of this total ( average 17.2%; range 14.8 – 19.0%; s.d. = 1.9) was tracked to the mainstem Alsek-Tatshenshini, between sites A and B (Smith et al. 2009). Chinook radio telemetry studies in 2002 indicated only 0.6% of the total radio tagged Chinook were tracked to the region between sites A and B (Pahlke and Waugh 2003). A sonar

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 19 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT enumeration program at Site A would still count a larger proportion of salmon returning to the system than the existing stock assessment program located further upstream. However, in terms of total proportion of sockeye run size counted, Site B would be superior because of its lower location in the watershed.

Upon careful consideration, the bathymetry, flow patterns, channel confinement and logistical merits of Site A were thought to outweigh the more favorable downstream location of Site B. For these reasons, Site A was selected as the best site to test a multi-beam sonar.

3.5 SONAR TESTING AND DEPLOYMENT

3.5.1 Site Selection

The ARIS sonar test at Site A included deployment at three test sites, where the bathymetric data showed the most even, consistent river bed slope. Figure 5 shows the locations and approximated cross-sectional profiles of each deployment site, on the bathymetric map for Site A.

Deployments 1 and 2 were conducted at the narrowest part of Site A, where the fastest water velocities were observed. Some turbulent flow was evident in this area, and was visible on the sonar image. Deployment 3 was conducted downstream of the turbulent flow in a wider part of Site A; the location of deployment 3 was chosen where the flow patterns looked the most laminar.

Deployment sites were selected with the understanding that they would also need to be viable at much higher flows. Bathymetric profiles are also subject to inter and intra annual changes as a result shifting of substrate during high water events and ongoing alluvial processes. The results of the sonar tests at each deployment site are discussed in the following sections.

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Deployment 1 Cross Section

Right Bank Left Bank 0 .0

-0.5 )

m -1 .0 (

h t p

e -1.5

D ³ -2 .0

-2.5 0 0 0 0

0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 0 1 1

3 Length (m) 3 6 6 6 6

Deployment 2 Cross Section Deployment 1

Left Bank Right Bank 0 .0

-0.5 )

m -1 .0 (

h t

p -1.5 e D -2 .0 -2.5 Deployment 2

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Length (m)

Deployment 3 Cross Section

Left Bank Right Bank 0 .0 -0.2 -0.4 ) m

( -0.6

h t

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0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 0 9 9

0 Length (m) 0 3 3 6 6 6 6

Length (m)

m Direction of flow 0 0 4

0 0 Right Bank 4 Left Bank 0 0 0 0 8 8 0 0 3 3 6 6 6 6

Legend Yukon * Figure 5. Test Deployment Sonar Deployment Site British Columbia

H Locations of ARIS Sonar at Site A a Shoreline in

T e

t s

Thalweg (estimated) A h H

l e i s g Data Sources n h e Site A s w Topographic Spatial Data courtesy of Her Majesty the Queen in Right of Canada, k Bathymetric contour (0.25 m interval) h a

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3.5.2 Echogram Interpretation

An echogram is the visual representation of sonar data; it is a sound image, based on sound frequency, intensity of returned echoes, and time. The DIDSON Control and Display Software provides a means to generate echograms from recorded ARIS data. Figure 6 shows an example echogram with approximately 3 minutes of recorded sonar data. Time is displayed on the horizontal axis and the distance from the front of the sonar transducer is displayed on the vertical axis. Whiter portions of the echogram indicate higher intensity sonar signals (i.e. echoes), while darker areas indicate weaker sonar signals. Horizontal lines on the echogram are static objects, most often reflected sound from the river bottom. When testing a sonar system, a series of horizontal lines through the entire Echogram is desirable; it indicates insonification of the river bottom at all distances from the transducer. However, small areas of the echogram where the river bottom is not insonified can often be mitigated by sonar aiming and/or through the use of weirs. Vertical lines on the echogram often represent background noise (e.g. turbulent flow). A sonar image without vertical lines is preferred; too much background noise can obscure passing fish.

Figure 6: Example of an echogram produced from ARIS sonar data, using the DIDSON Control and Display Software.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 22 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.5.3 Deployment 1

Deployment 1 was conducted on the right bank of the river, near the upstream end of Site A. A small area of sandy shore was present in this location (Photo 11). The channel width in this area was approximately 43 m. The ARIS was installed approximately 8 m from the high water mark on the right bank; the distance from the ARIS to the wetted edge and the high water mark on the left bank was approximately 35 m. A transducer pitch of approximately -2.5 degrees provided the best sonar image.

Photo 11: View of the ARIS sonar and mount at Deployment 1, note the turbulent flow present mid-channel, September 11, 2012. The red arrow indicates the direction of insonification. An echogram of deployment at Site 1 is shown in Figure 7. The river bottom is visible between 11 and 26 m, but becomes much fainter from 26 to 35 m. The vertical lines between 0 and 10 m are due to turbulent flow. The background noise resulting from this turbulence could obscure weaker objects within that portion of the Echogram, especially fish targets. The turbulence in the near shore portion of the echogram is also problematic; any bank oriented salmon would be expected to migrate within this part of the river. The observed turbulence and lack of river bottom insonification between 26 and 35 m would make sonar operation at deployment 1 challenging.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 23 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Figure 7: Deployment 1 echogram.

3.5.4 Deployment 2

Deployment 2 was conducted from the left bank of the river, near the upstream end of Site A. At this location, a small rise was present near the left bank. The channel width at this location was approximately 42 m. The ARIS was deployed offshore, approximately 10 m from the high water mark on the left bank (Photo 12), to overcome this rise. The distance from the ARIS to the wetted edge and the high water mark on the right bank was approximately 28 m and 32 m, respectively. A transducer pitch of approximately -5.4 degrees provided the best sonar image.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 24 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 12: View of the ARIS transducer and mount, installed at Deployment 2, September 12, 2012. The red arrow indicates the direction of insonification. An echogram of deployment 2 is shown in Figure 8. High intensity echoes were present between 0 and 6 m; however, clear horizontal lines indicating river bottom were not. The river bed was not effectively insonified until approximately 20 m from the transducer. Turbulent flow was also detected between 12 and 19 m. Strong river bottom signals were visible from approximately 20 to 28 m. The horizontal line present at 3 m is likely due to a rock or similar bottom feature; this could be avoided by moving the transducer a small distance upstream or downstream.

Deployment 2 was less impacted by turbulent flow than deployment 1, but less river bottom was insonified. The bathymetric contours in the vicinity of deployment 2 (Figure 5) suggest that a submerged bar may be responsible for the bright lines at 20-23 m from the transducer, and hence, the shadow after 24 m along the far (offshore) side of this bar. Sonar aim was adjusted upstream and downstream during testing, in attempt to overcome the shadow at 24 m; however, no change in the echogram was observed in response to these adjustments.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 25 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Figure 8: Deployment 2 echogram.

3.5.5 Deployment 3

Deployment 3 was conducted from the left bank of the river, near the downstream end of Site A. The channel width was approximately 44 m. To achieve an unobstructed field of view, the ARIS was deployed on the offshore side of a gravel bar, approximately 15 m (from the high water mark on the left bank (Photo 12). The ARIS was deployed approximately 28 m from the wetted edge of the right bank and approximately 29 m from the high water mark. A transducer pitch of approximately -3 degrees provided the best sonar image.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 26 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 13: View of the ARIS transducer and mount installed at Deployment 3, September 12, 2012. The red arrow indicates the direction of insonification. An echogram of deployment 3 is shown in Figure 9. High intensity echoes were present approximately 0 to 8 m from the transducer. The river bed was well insonified throughout most of the echogram, from approximately 8 to 22 m, and 25.5 to 28 m. The insonification gap of the river bed between 22 and 25.5 m is likely due to a depression at the thalweg resulting in an acoustic shadow near the river bed. If this shadow is determined to be of sufficient depth to hide passing salmon it could be eliminated through the use of a weir.

Deployment 3 provides the highest quality insonification of the river channel of all three ARIS test deployments. The river bottom was visible throughout the majority of the echogram and turbulent flow was relatively absent.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 27 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Figure 9: Deployment 3 echogram.

3.5.6 Review of Sonar Data

At each deployment, the sonar was left to record for several hours after the required site testing had been completed. The sonar testing was not conducted with the aim of observing migrating salmon nor was it a stated project goal; nonetheless, recorded data was reviewed to determine if any salmon could be observed. No salmon were observed in any of the recorded data files. No fish deflection fences were in place during the sonar testing; if salmon were migrating through the site during the sonar tests they could have travelled behind the sonar. Salmon could also have passed through areas of turbulent flow and/or within the detection gaps described in the preceding sections.

3.6 CONSIDERATIONS FOR FUTURE PROGRAM DEVELOPMENT

The next step in the development of a sonar program on the Tatshenshini River would be to initiate a pilot project; however, a number of challenges must be considered prior to proceeding. These considerations include:

 Run timing and stock composition;  Tatshenshini River water level fluctuations;  Equipment requirements;  Species apportionment (i.e., drift net testing);  Logistical considerations related to the remote location.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 28 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.6.1 Run Timing and Stock Composition

Chinook, sockeye and coho salmon are co-migrating species within the Alsek-Tatshenshini rivers; these species all run in conjunction with at least one of the others. Considerable research has been conducted on Chinook and sockeye salmon run timing and stock composition, whereas coho and chum salmon run timing and stock composition are less understood. The section below discusses the run timing and stock composition Chinook and sockeye salmon, and the implications for a sonar enumeration project based at Site A.

The Chinook and sockeye salmon runs entering the Alsek - Tatshenshini River system are each composed of several discrete stocks. This results in a protracted run for each species without a well-defined peak. Run timing is variable, but previous studies indicate that Tatshenshini River origin Chinook and sockeye salmon typically enter the lower Alsek River from early to mid-May (Smith et al. 2009; Pahlke and Waugh 2003). Chinook salmon continue to enter the system until mid-July, and sockeye salmon were observed entering the lower Alsek River until the end of August (Figure 10 and Figure 11). The Tatshenshini sockeye run completely overlaps with the Chinook run. In order for a sonar program situated at either Site A or B to fully count both the Chinook and sockeye runs, it would need to be continuously operational between approximately June 1 and September 30. For complete Chinook salmon enumeration, the sonar would be required to operate from June 1 to late August.

A three year radio telemetry study of Tatshenshini River sockeye salmon indicated that an average of 38.4% (range 25.3% – 43.1%; s.d. = 7.5) of the total Alsek-Tatshenshini run was located below sonar Site A (Smith et. al. 2009). The sockeye stock groupings that would be counted by sonar deployed at Site A include the Upper Tatshenshini, Village Creek, Klukshu, Takhanne and Blanchard stocks (Figure 12). Chinook salmon telemetry studies, conducted on the Alsek - Tatshenshini River in 1998 and 2002 indicated that 35.7% and 13.7% of radio tagged fish were tracked to spawning areas downstream of Site A, respectively (Pahlke and Waugh 2003). The Chinook salmon stock groupings that would be counted by the sonar deployed at Site A include the Low Fog, Upper Tatshenshini, Village Creek, Klukshu, Takhanne and Blanchard stocks (Figure 13).

There will be intra-annual variation in the relative proportions of each stock grouping within the Tatshenshini system. However, based on the radio telemetry studies, sonar deployed at Site A would likely count approximately 75% of the annual Alsek-Tatshenshini Chinook salmon run, and approximately 65% of the annual sockeye salmon run.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 29 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Figure 10: Comparison of catch-per-unit-effort (CPUE) of sockeye salmon and radio tags applied on the lower Alsek River, 2001 – 2003. (Chart Source: Smith et. al. 2009).

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 30 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Figure 11: Chinook and sockeye salmon catches in a 13.5 cm mesh gillnet on the lower Alsek River, 2002 (Chart Source: Pahlke and Waugh 2003).

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EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 32 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.6.2 Tatshenshini River Water Level Fluctuations

The Water Survey of Canada (WSC) maintains a water level gauging station on the Tatshenshini River, near Dalton Post, approximately 46 km upstream of Site A (WSC station 08AC002). Historical discharge data (1989 to 2011) was reviewed to determine the expected magnitude of discharge fluctuations during the timing of sonar system operations (June to October; Figure 14)

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 33 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

The discharge recorded at WSC station 08AC002 during the 2012 field visits was 60, 52 and 35 m³/s on August 6, August 29 and September 11, respectively (Environment Canada 2012a). These values are slightly above the historical mean and median discharges; however, the maximum discharge values recorded on these dates are considerably higher (Figure 14). An understanding of the relative difference between the discharges observed in 2012 and the historical maximum flows is important, but peak mean and median discharges during the early summer are more representative of high water levels that could be expected during any given year.

Historically (1989 – 2011), a mean discharge of 105 m³/s has occurred mid-June (Figure 14). Following this peak, mean discharge typically decreases steadily in the summer to reach a mean of 13 m³/s at the end of October. The historical median discharge is close to the mean values throughout the season, which indicates that discharges in excess of 100 m³/s occurred somewhat frequently throughout the period of record. The maximum recorded discharge between June 1 and October 30 is 257 m³/s.

Based on this data review, mean water levels of at least 100 m³/s can be expected in June, and high water events can result in discharge of up to 250% higher than the mean. Sonar deployment will need to contend with at least twice as much water as was observed in the 2012 field investigations, and peak discharge may be up to five times greater than that observed in 2012. The confined river channel at Site A and the amount of large woody debris present in the area could cause disruptions to sonar operations. Tatshenshini Chinook salmon run timing (Section 3.6.1) indicates that peak passage past the sonar sites would typically occur from mid-June through early July, the period of greatest discharge. A significant proportion of the sockeye salmon run would also be expected to pass the sonar sites during this period.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 34 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

300

250

Minimum Discharge 200

Maximum Discharge

Mean Discharge

³/s)

150 Median Discharge

Discharge (m

Discharge during 2012 Site Visits

100

0 01-Jun 08-Jun 15-Jun 22-Jun 29-Jun 06-Jul 13-Jul 20-Jul 27-Jul 03-Aug 10-Aug 17-Aug 24-Aug 31-Aug 07-Sep 14-Sep 21-Sep 28-Sep 05-Oct 12-Oct 19-Oct 26-Oct Date

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 35 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

The channel confinement at Site A offers several advantages for sonar operation; however, during high flow periods the confinement may result in substantial increases in the water level. Large increases in water levels were evident in the observed high water mark and bank scour at least 1 m above the water level at the time of the field investigations (Photo 14). Ensuring that sonar weir equipment is strong enough to handle an additional 1 m of water depth will be a considerable challenge.

A large number of uprooted trees were noted on the large gravel bar upstream of Site A (Photo 15). The presence of green foliage suggests they were likely uprooted during the summer of 2012. Trees like this could severely damage or destroy a weir and/or sonar mount. A brief discussion of some of the equipment that may be suitable for these conditions is given in the following section.

Photo 14: View of the left bank of Site A, showing evidence of bank scour during high flow, September 11, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 36 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 15: View of a large, uprooted tree on the gravel bar upstream of Site A, September 11, 2012.

3.6.3 Equipment Requirements

There are sonar mounts and weir systems designed to withstand high water velocities. DFO staff who have operated these systems indicate that a stepladder sonar mount and a deep-water, sectional, aluminum weir could be deployed at Site A (H. Enzenhofer, pers. comm., November 2012).

The ladder mount (Photo 16) consists of a welded aluminum ladder, with an adjustable sonar mounting plate affixed to the offshore end of the ladder. The ladder design incorporates six stainless steel anchor pins, which are driven into the river bed to stabilize and strengthen the ladder. A deep-water sectional weir used on the Chilko River, B.C. is shown in Photo 17; the offshore end of this weir was deployed in 2 m of water. A similar structure may be used at Site A at certain water levels. This weir can be transported in pieces and assembled on site.

Another option for a deep water deflection fence would be of the type currently used at BMA’s Big Salmon River sonar site, a tributary of the upper Yukon River drainage. This fence frame consists of 2 m high steel tripods, with cross ties installed between the tripods; the fence itself is constructed of welded interlocking panels (Photo 18). This structure can be assembled from a boat in deep (2m) fast flowing rivers. It is a robust design that has been used at three other weir projects on the Yukon and Transboundary rivers and is able to withstand severe high water events. This fence can be transported in modules, and fabricated on site.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 37 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

The equipment described above is designed for use in sites where high flows are anticipated, but it must be stressed that it may not be sufficient to allow for uninterrupted operation during all high flow events. In particular, it would be inadvisable to position a sonar unit in a mid-stream location during a severe high water event regardless of the mounting structure used. In these instances, the only course of action may be to remove all instream equipment until water levels decrease to a manageable level. At certain locations within Site A (dependent on a suitable bathymetric profile), it may be possible during high water events to deploy a long range high definition sonar positioned close or adjacent to the shore. Use of a 3° or 8° DIDSON/ARIS concentrator lens may allow for salmon size targets to be detected at the increased ranges.

Photo 16: View of a ladder type sonar mount installed instream. Photo provided by H. Enzenhofer, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 38 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

Photo 17: View of a sectional, deep-water, aluminum weir installed on the Chilko River, B.C. Photo provided by H. Enzenhofer, 2012.

Photo 18: View of a deep-water steel tripod weir installed on the Big Salmon River, Yukon. BMA Photo, 2012.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 39 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

3.6.4 Species Apportionment

Currently, there is no reliable method, using high definition multi-beam sonar (e.g. ARIS or DIDSON), to accurately identify and distinguish similar sized species of co-migrating salmon. A species apportionment component will be required throughout the overlapping Chinook and sockeye migrations, to determine what portions of sonar counts represent each species. Drift netting with gillnets of varying mesh sizes provides an effective, efficient means to apportion the sonar counts between species (EDI 2011; Withler 2006).

To provide confidence in the species apportionment data, the drift netting must be conducted near the sonar deployment site. A potentially suitable site for drift netting was identified several hundred meters downstream of Site A; where the river widens and the flow appeared to decrease. Reduced water depth and flow would allow for easier and safer handling of a drift net than the narrow, fast flowing river channel at Site A. Instream obstructions that could impair the operation of drift net (e.g. large boulders) were not observed in this area. It is recommended that a drift netting test be conducted to confirm the suitability of this site.

3.6.5 Logistical Considerations

Site A is 50 km from Dalton Post, by river. It is a remote site and access is challenging. All 2012 field work was conducted via helicopter; however, the area is mountainous and may not always be accessible by air. The gravel bar upstream of Site A provides a suitable landing area, but is likely submerged at higher flows. Any camp facilities would therefore need to include the construction of a landing area outside of the river floodplain area.

Boat access from Dalton Post is possible, but a large whitewater canyon must be navigated in order to reach Site A. Circumventing this canyon is possible via a 4 wheel drive, un-improved road, from Dalton Post to a location downstream of the canyon. This requires fording the Tatshenshini River with a vehicle; a difficult or impossible task during periods of high water. Safe navigation of the river requires a powerful boat and an experienced operator; an outfitter local to the area has also indicated that the river can become unnavigable at higher flows (L. Goodwin, pers. comm., July 2012). Careful consideration should be given to ensure that any field camp can be safely provisioned and/or evacuated.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 40 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

4 CONCLUSIONS

The Tatshenshini is large, swift flowing river characterized by large seasonal variations in discharge; any sonar deployment on this river will be technically and operationally challenging. The results of the 2012 Tatshenshini River sonar site reconnaissance indicate that a DIDSON or ARIS sonar system could enumerate salmon on the Tatshenshini River at Site A under the conditions observed during the 2012 field investigations; however, historically, river discharge in August and September is well below peak (early summer) levels. The observed physical site parameters, bathymetry and flow patterns in the vicinity of Deployment 3 are conducive to sonar operation. A DFO field camp could be installed at Site A. Drift netting appears feasible at a site several hundred meters downstream, but must be confirmed via onsite testing. If successful, a sonar program on the Tatshenshini River could enumerate a greater proportion of the Chinook and sockeye salmon runs than existing upstream stock assessment program; however, a certain percentage of both runs would still be unaccounted for a Site A due to spawning in the lower reaches of the river.

Effective enumeration of Tatshenshini River Chinook and sockeye salmon would require a sonar program to commence operation by June 1. Peak flows will occur near this time of year, and will be higher than those observed during 2012 field investigation. This is expected to be the biggest challenge to the operation of a sonar program at Site A. High flow is typically in June; however, historical discharges of over 100 m³/s (approximately double the levels observed in 2012) have been recorded at the WSC gauging station near Dalton Post as late as mid-October (Figure 14). Careful selection of sonar mounts and weir equipment will make sonar operation more feasible during high water conditions, but will not guarantee operation under all conditions. Site access during high water must also be addressed.

Prior to further program development, Site A should be visited during early summer peak flows (most likely in late June). An ARIS or DIDSON should be redeployed and tested, using a mounting apparatus suitable for deep water and high velocity current. A deep water weir could also be tested at this time. This would allow for a determination of the feasibility of operating sonar during higher flows. Drift netting should also be attempted during the peak of the Chinook and/or sockeye run to ensure that a reliable test fishery can be operated to apportion sonar counts. If the concerns regarding drift netting and sonar operation during high water at Site A can be addressed successfully, further program development could proceed.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 41 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

5 REFERENCES

5.1 PERSONAL COMMUNICATIONS

Enzenhofer, H. 2012. Sonar Expert, Fisheries and Oceans Canada. Communication via e-mail, November 11, 2012.

Goodwin, L. 2012. Owner, Noisy Range Enterprises. Communication via e-mail, July 23, 2012.

5.2 CITATIONS

EDI Environmental Dynamics Inc. 2011. Porcupine River Fall Chum Salmon Sonar Program (CRE- 114N-11). Prepared for the Vuntut Gwitch’in Government.

Environment Canada. 2012a. Water Survey of Canada Real-Time Hydrometric Data, Station 08AC002, Preliminary Daily Discharge Data. http://www.wateroffice.ec.gc.ca/graph/graph_e.html?stn=08AC002. Accessed November 6, 2012.

Environment Canada. 2012b. Water Survey of Canada Archived Hydrometric Data, Station 08AC002, Daily Discharge Data. http://www.wsc.ec.gc.ca/applications/H2O/HydromatD-eng.cfm. Accessed November 6, 2012.

Pahlke, Keith A., and Bill Waugh. 2003. Abundance and distribution of the Chinook salmon escapement on the Alsek River, 2002. Alaska Department of Fish and Game, Fishery Data Series No. 03-20. Anchorage.

Smith J.J., B. Waugh, P. Etherton, K. Jensen, and S. Stark. 2009. Alsek River sockeye salmon radiotelemetry studies, 2001 – 2003. Report for the Pacific Salmon Commission, Vancouver.

Withler, P. 2006. Eagle Sonar 2006: Progress Report for the Sonar Site at Six Mile Bend (CRE-110-06). Prepared by Pacific Eumetrics Consulting Ltd. for the Yukon River Panel Restoration and Enhancement Fund.

EDI Project #: 12-Y-0319 EDI ENVIRONMENTAL DYNAMICS INC 42 2012 Tatshenshini River Sonar Site Reconnaissance - DRAFT

5.3 SPATIAL DATA

1:50,000 CanVec topographic data from Government of Canada, Natural Resources Canada, Earth Sciences Sector, Centre for Topographic Information. Geogratis website (http://geogratis.cgdi.gc.ca).

1:20,000 TRIM positional files from the Land and Resource Data Warehouse (http://lrdw.ca). Copyright belongs to Her Majesty the Queen in Right of the Province of British Columbia.

Disclaimer: Maps presented in this document are a geographical representation of known features. Although the data collected and presented herein has been obtained with the utmost attention to quality, this document is not an official land survey and should not be considered for spatial calculation.

EDI Environmental Dynamics Inc. does not accept any liability for errors, omissions or inaccuracies in the data.

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