Taltson Hydro Project
NORTHWEST TERRITORIES POWER Northwest Territories Power Corporation CORPORATION Yellowknife, NorthwestTerritories
Taltson Hydro Project 2003 Water Effects Monitoring Program
Prepared by: March 2004
Rescan Environmental Services Ltd. Yellowknife, Northwest Territories EXECUTIVE SUMMARY
(Rescan)™ Executive Summary
As a result of water licence requirements pertammg to Notihwest Territories Power Corporation's (NTPC) Taltson liydro Project, a Water Effects Monitoring Program (WEMP) was developed with the objective of "providing a means of efficient and effective identification of short-term, long-tem1, and cumulative changes in the water environment resulting from the project.'' This report presents results of the 2003 WEMP undertaken by RescanTM Environmental Services (Rescan) for the NTPC. The following is a brief summary of the work completed for the 2003 WEMP as well as recommendations derived from the examination of the overall objectives of the WEMP.
Hydrology
The WEMP requires the development of a detailed understanding of the hydrology of the Taltson Watershed, so that predictions can be made of the effects of dam operation and varying climatic conditions on water levels and discharges throughout the watershed. During 2003 the hydrological work was concentrated on the collection and analysis of available meteorological and hydrometric data, and on a program of field data collection that included the setting up of topographic benchmarks along the river and the measurement of river flow and channel cross sections at key locations.
The data collection and review work undertaken during 2003 has resulted in an understanding of the broad-scale hydrological response of the Taltson Watershed and the annual variability in that response. A key conclusion of the data review was the identification of possible long-term climatic trends affecting the hydrological response in the watershed. The data review also identified a number of gaps in the existing data, which limited understanding of the hydrology of key reaches of the river system. Hence, for future years it is recommended that further and more detailed field studies be undertaken, in tandem with the development of a mathematical model of the Taltson Watershed. Specifically. manual flow and water level measurements should be collected four to five times throughout the open water season. Stage-discharge curves and mathematical modeling work can be developed with these data.
Ice Characterization
The WEMP requires that a detailed understanding of the ice freeze-up process be obtained and used to generate a model of the Taltson River system under various flow regimes and water management practises. To begin this process of model development, a detailed survey of the freeze-up process was completed in November 2003. A helicopter flown at low level was used to facilitate filming of the main site of the Taltson River from Taltson Bay at Great Slave Lake to Nonacho Lake. The survey team made periodic landings to dete1111ine ice thickness and collect water temperatures at various depths of lakes and river sections of the Taltson River system.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - i - Rescan"' Environmental Services Ltd. (Proj. #664-1) Executive Summary
The Taltson River between Taltson Bay at Great Slave Lake and Nonacho Lake can be characterized as a chain of large lakes interconnected with a series of channels. At the outlet of each lake, the lake level is maintained by a rock sill and then a set of rapids that release the flow to the next lake downstream. ln between sets of rapids. the flow is generally slow moving and an ice cover develops quickly. In narrow sections and shallower reaches where the velocities are higher. thermal ice may not always be able to form so easily. These reaches will stay open longer and may close either with a juxtaposed ice cover or by the process of accumulation and staging. This type of ice cover formation was identified at several locations along the river, especially in Trudel Creek. In the early stages of freeze-up in particular. the ice covers in these reaches will be thin compared to low velocity sections.
Fast moving rapid sections will take even longer to freeze over, if at all, due in pait to the warmer water coming out of the lakes. Small rapids are usually able to close through staging from downstream, but rapids with a greater drop may stay ice-free all winter.
The biggest change in terms of ice processes following development of the Taltson Hydro Project has taken place in Trudel Creek, between Elsie Falls and the South Valley Spillway. Under present plant operating conditions, this small channel now carries approximately 75% of the total Taltson discharge. All types of ice are generated in this reach. from thermal ice covering the lakes to anchor ice below the spillway and in the rapids.
Fish
In July, August and September 2003, a fish sampling program was carried-out within the Taltson Watershed including three lakes (Nonacho. Taltson and Rutledge) and the Taltson River itself. These waterbodies were selected for monitoring as paii of the WEMP. Fish were sampled with experimental gillnets and all captured fish were identified to species. counted, measured and weighed. All fish were to be examined externally for deformities, erosions. lesions and tumours. A subset of lake trout lake \Vhitefish and walleye from a range of size classes were sacrificed and various parts were collected such as otoliths, stomachs. fillets, and muscle tissue.
A total of 524 fish were captured during the 2003 survey. Lake whitefish and lake trout accounted for the majority of the fish caught in all three lakes. The highest fish diversity was in the Taltson River with eight species captured (lake trout lake whitefish. northern pike, walleye. longnose sucker, white sucker, trout-perch, and burbot). Lake trout was not as abundant in the Taltson River compared to the other lakes because lake trout are predominantly a lake dwelling species.
The average lake trout fork length was similar for both Taltson Lake and Taltson River, but was higher than the average length observed in both Nonacho and Rutledge lakes. The average lake trout length was the same in both Nonacho and Rutledge lakes. Lake whitefish from Nonacho, Taltson and Rutledge lakes had similar average fork lengths, while lake whitefish from the Taltson River were significantly smaller on average. All lake trout length-frequency
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - ii - Rescan"'' Environmental Services Ltd. (Proj. #664-1) Executive Summary distributions have very narrow distributions in all four waterbodies. Lake whitefish length frequency modes were widely distributed when compared to lake trout, and tvvo modes were present in all lakes. Condition factor of lake whitefish and lake trout were significantly higher in Taltson Lake compared to Nonacho and Rutledge lakes. There were no significant differences in average condition among either lake whitefish or lake trout in Nonacho Lake, Rutledge Lake and the Taltson River.
For lake whitefish, the among-population differences were highly significant. The average age of lake whitefish in Nonacho Lake was significantly greater than the average age of lake whitefish in both the Taltson Lake and in the Taltson River. The average age of lake whitefish in Rutledge Lake was significantly greater than the average age of lake \Vhitcfish in the Taltson River. The average age of lake trout in Taltson Lake was significantly greater than the average age of lake trout in both Nonacho Lake and Rutledge Lake.
Nonacho lake trout had significantly higher average mercury concentrations than Rutledge Lake lake trout for a standardized length, while no significant difference in lake trout mercury concentrations were observed between the other two waterbodies or between those waterbodies with Nonacho or Rutledge lakes. Mercury concentration in lake whitefish were significantly higher in Nonacho Lake compared to the other three waterbodies.
Fish diets for lake whitefish consisted mainly of benthic organisms such as amphipods, molluscs and mysids. However, lake whitefish of Rutledge Lake had a slightly different diet that compared to those of Nonacho and Ta Itson lakes. The stomachs from Rutledge Lake contained fewer amphipods and greater weight of fish and mysids. Lake trout diets were composed mainly of a few big fish and many small invertebrates. Unlike lake whitefish, these organisms would have been eaten from both benthic and planktonic environments. Lake trout from Nonacho Lake appeared to eat fevver fish and more mysids than lake trout from Taltson and Rutledge lakes.
There were no tumours observed in any of the fish captured. The incidence of deformities, erosions and lesions was very low for Nonacho Lake. Rutledge Lake and Taltson River; however, the incidence of deformities, erosions and lesions was higher in Taltson Lake. The number of Ttiaenophorus crassus that were observed in a fillet ranged from O to 35 for lake whitefish and from Oto 15 for lake trout.
Overall, the fish communities between the three lakes were similar in general. however there were significant differences for some variables. The fish community in the Taltson River was different than in the three lakes due to its physical characteristics.
Aquatic Biology & Chemishy
As part of WEMP requirements, non-fish variables had to be sampled for the biological monitoring program. Variables analyzed during the 2003 program included physical limnology (transparency (Secchi depths), dissolved oxygen and temperature), conductivity, total dissolved solids, sediments and aquatic plants for mercury analysis, and benthic inve1tebrates.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report iii - Rescan n, Environmental Services Ltd. (Proj. #664-1) Executive Summary
The physical limnological characteristics and water quality of the Nonacho Lake and Rutledge Lake were indicative of northern lakes within the region. Both lakes were well mixed and well oxygenated, with conductivity and total dissolved solids concentrations being relatively low and similar among stations within each lake. Sediment mercury concentrations were slightly higher in Rutledge Lake compared to Nonacho Lake. Sediment mercury concentrations were well below the federal guideline for the protection of aquatic life. Aquatic plants collected in Nonacho Lake had slightly higher mercury concentrations compared to Rutledge Lake; however, all values were below the federal guideline. The benthic macroinvertebrate community was very similar among both waterbodies sampled and was dominated by molluscs, amphipods and dipterans.
Beaver
One of the components of the WEMP is to periodically monitor beaver (Castor canadensis) populations in waterbodies associated with the dam and related facilities. This repo1i details aerial surveys conducted in fall 2003 to determine the abundance and distribution of beaver lodges in the areas examined during a similar survey in 2000. An aerial beaver lodge survey, also known as a fall food cache survey, was conducted to census populations in waterbodies in the vicinity of the Twin Gorges generating station on the lower Taltson River, the Nonacho Lake reservoir further upstream on the Taltson system, and the Hanging fee Lake System.
The survey was conducted on September 30 and October l, 2003 under excellent survey conditions. Forty-three active and 40 abandoned beaver lodges were observed. similar to the 44 active lodges observed in 2000, suggesting little change in beaver population size over the past three years.
The recommended five years between subsequent surveys will track gross population changes over time, although more frequent monitoring may be required to verify significant changes in abundance or distribution should they be suspected. Surveys of Nonacho and Porter lakes, marginal beaver habitat with few active lodges, should be dropped, since these areas contribute little to the objectives of the WEMP.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - iv - Rescan™ Environmental Services lid, (Proj, #664-1) ACKNOWLEDGEMENTS
(jtescan)™ Acknowledgements
This report was produced by Rescan TM Environmental Services Ltd. (Rescan). The following Rescan scientists and sub-consultants to Rescan conducted field work and \Vere major authors of the report: Elizabeth Fillatre (M.Sc.), Sophia Granchinho (ivl.Sc.), Graham Holder (Eng.), Frarn;ois Landry (ivLSc., R.P. Bio.), Michael McGurk (Ph.D., R.P. Bio.), Kim Poole (M.Sc., R.P. Bio), Ralph Silver (Eng.). Michael Stewart (Ph.D), Shane Uren (M.A.Sc., R.P. Bio.). The following Rescan personnel conducted field work for the report: Rob Harmer (M.F.A.) and Jonathan Olsen (B.Sc. Hons.). Joanna Lerner vvas responsible for production coordination. The following Rescan scientists assisted with data analysis. GfS mapping and repott editing: Tania Perzoff (ivl.Sc., R.P. Bio.) Rosemary Spicker (B.Sc.) and Sally Stewmi (Ph.D.). Rescan scientists received excellent support in the field from local assistants John Desjarlais (Fort Smith), Danny Macdonald (Fort Smith) and Stanley Beck (Fort Resolution). Special thanks to Tom Vernon. Project Manager. for his constant assistance and support throughout the project.
Field workers were stationed at the Twin Gorges Generating Station and Nonacho Lodge while conducting field work. Special thanks to Allan Crawford and the entire Catter family for their hospitality throughout the summer.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - v - Rescan TM Environmental Services Ltd, (Proj, #664-1) TABLE OF CONTENTS
(ilescan)™ Taltson Hydro Project: 2003 ater Effects onitoring Program
TABLE OF CONTENTS
Executive Summary ...... i
Acknowledgements ...... v
Table of Contents ...... vii List of Appendices ...... xi List ofFigures ...... xiii List of Tables ...... xviii List of Plates ...... xxi
Glossary ...... xxii
1. Introduction ...... ; ...... 1-1 1.1 General ...... l-1 1.2 2003 WEMP ...... 1-3 l .2. l Program Objectives ...... 1-3 l .2.1.1 Hydrology ...... 1-3 1.2. l.2 lee Characterisation ...... 1-4 l .2. 1.3 Fish ...... 1-4 1.2.1.4 Aquatic Biology and Chemistry ...... 1-5 1.2.1.5 Beaver Survey ...... 1-5 1.3 Study Areas ...... : ...... 1-6
2. Methods ...... 2-1 2.1 Hydrology ...... 2-1 2.1. l Reconnaissance ...... 2-1 2.1.2 GPS Survey ...... 2-1 2.1.3 Flows & Cross-sections: ADCP ...... 2-2 2.1.4 Taltson Local Datun1s ...... 2-4 2.2 Ice Characterisation ...... 2-5 2.2. l Freeze-up Process Survey ...... 2-5 2.2.2 Ice Thickness Measurements ...... 2-5 2.2.3 Water Temperature Profiles ...... 2-5 2.3 Fish ...... 2-6 2.3.1 San1pling Program ...... 2-6 2.3.2 Data Analysis ...... 2-11
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2.3.3 Quality ,'\ssurance/Quality Control (Q1\/QC) ...... 2-12 2.4 Aquatic Biology and Chemistry ...... 2-12 2.4. l San1pling Program ...... 2-12 2.4.1.1 Physical Limnology ...... 2-13 2.4.1.2 Conductivity and Total Dissolved Solids ...... 2-16 2.4.1.3 Mercury in Sediment...... 2-17 2.4.1.4 Mercury in Aquatic Plants ...... 2-17 2.4.1.5 Lake Benthos ...... 2-18 2.4.2 Quality Assurance/Quality Control (QA/QC) ...... 2-20 2.5 Beaver Lodge Survey ...... 2-20 2.5.1 Study Area ...... 2-20 2.5.2 Beaver Lodge Survey ...... 2-22
3. Results and Discussion ...... : ...... 3-1 3.1 Hydrology ...... 3-1 3.1. l Taltson \Vatershed ...... 3-l 3.1.2 Lake Surface Areas ...... 3-4 3.1.3 Historical Data ...... 3-5 3.1.3.1 Meteorological Data ...... 3-5 3.1.3.2 Hydrometric Data ...... 3-7 3.1.4 Analysis of Historical Data ...... 3-9 3.1.4.1 Meteorological Data ...... 3-11 3.1.4.2 Hydrometric Data ...... 3-16 3.1.5 High-level and Shore/Bank Benchmal'ks ...... 3-30 3.1.6 Measured Water Level Profile on the Taltson River System ...... 3-30 3.1. 7 River Flow and Cross-Section Measurements: Acoustic Doppler CmTent Profiler ...... 3-42 3.1.8 Rating Equations at Key Control Points within the Taltson River System ...... 3-43 3.1.8.1 NonachoLake ...... 3-44 3.1.8.2 Twin Gorges Forebay ...... 3-49 3.1.8.3 Taltson River downstream of Elsie Falls ...... 3-51 3.2 lee Characterization ...... 3-53 3.2. l Meteorological & Hydrological Conditions ...... 3-53 3.2. l .1 Discussion of Findings ...... 3-56 3.2.2 Ice Freeze-up Processes on Nordic Rivers ...... 3-56 3 .2.2.1 Natural River Ice Conditions ...... 3-56 3.2.2.2 Hydroelectric Projects & River lee ...... 3-60 3.2.3 Taltson River lee: Freeze-up ...... 3-61 3.2.4 Reach I - Great Slave Lake to Tsu Lake Outflow ...... 3-61 3.2.4.1 Waypoints 222 to 220 ...... 3-73 3.2.4.2 Waypoints 220 to 217 ...... 3-73 3.2.4.3 Waypoints2!7to214 ...... 3-74 3.2.4.4 Waypoints 214 to 208/238 ...... 3-74 3.2.4.5 Waypoints 208/238 to 207 ...... 3-74 3.2.5 Reach 2 -Tsu Lake Outflow to entry to Twin Gorges Forebay ...... 3-75 3.2.5.1 Waypoints 207 to 232 ...... 3-75 3.2.5.2 Waypoints 232 to 231 ...... 3-75
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - viii - Rescann,, Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.2.5.3 Waypoints 231 to 229 ...... 3-76 3.2.5.4 Waypoints229to311 ...... 3-76 3.2.6 Reach 3 - Elsie Falls to Upstream End of Trudel Creek and Twin Gorges Forebay ...... 3-76 3 .2.6.1 Way points 320 to 318 ...... 3-77 3.2.6.2 Waypoints 318 to 315 ...... 3-77 3.2.6.3 Waypoints 3 I 5 to 311 ...... 3-77 3.2.7 Reach 4 - Entry to Twin Gorges Forebay to Tazin River ...... 3-78 3.2.7.1 Waypoints 311 to 308 ...... 3-78 3.2.7.2 Waypoints 308 to 300 ...... 3-78 3.2.7.3 Waypoints 300 to 290 ...... 3-78 3.2.8 Reach 5 -Tazin River to Nonacho Lake ...... 3-79 3.2.8.1 Waypoints 290 to 292/248 ...... 3-79 3.2.8.2 Waypoints 292/248 to 251/287 ...... 3-79 3 .2.8.3 Waypoints 251 to 256 ...... 3-79 3.2.8.4 Waypoints 256 to 257 ...... 3-80 3.2.8.5 Waypoints 257 to 271 ...... 3-80 3.2.8.6 Waypoints 271 to 279 ...... 3-81 3.3 Fish ...... 3-81 3.3. l Community Composition and Catch-per-Unit-Effort ...... 3-81 3.3.2 Length and Length-Frequency Distributions ...... 3-92 3.3.3 Weight. Weight-Length Relationships, and Condition ...... 3-98 3.3.3. l Weight and Weight-Length Regressions ...... 3-98 3.3.3.2 Condition ...... 3-98 3 .3 .4 Age and Growth ...... 3-102 3.3.4.1 Age-Frequency Distributions ...... 3-103 3.3.4.2 i\verage Age ...... 3-103 3 .3 .4.3 Growth ...... 3-110 3.3.5 Sex. Maturity, and Reproductive Status ...... 3-111 3.3.6 Mercury Concentrations in Fish Tissue ...... 3-118 3.3.6.1 Exceedance of Health Canada Guideline ...... 3-118 3.3.6.2 Regressions of Mercwy Concentration on Body Size ...... 3-l 20 3.3.6.3 Length-Standardized Mercury Concentrations ...... 3-120 3.3.7 Diet ...... 3-124 3.3.7.1 Lake Whitefish ...... 3-124 3.3.7.2 Lake Trout ...... 3-126 3.3.7.3 Summary ...... 3-128 3.3.8 Deformities, Erosions, Lesions, and Tumours ...... 3-128 3.3.9 Parasites ...... 3-132 3.3.9.1 Triaenophorus crassus ...... 3-133 3 .3. 9 .2 Among-Lakes Differences in Parasite Density ...... 3-13 7 3.4 Aquatic Biology and Chemistry ...... 3-137 3.4. l Physical Limnology ...... 3-138 3.4.1.l Secchi Depth ...... 3-138 3 .4.1.2 Dissolved Oxygen/Temperature Profiles ...... 3-140 3 .4. 1.3 Conductivity ...... 3-140 3.4.1.4 Total Dissolved Solids ...... 3-140 3 .4. l.5 Sum111ary ...... 3-146 3.4.1.6 Quality Assurance/Quality Control ...... 3-146
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - ix - Rescan"' Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.4.2 Mercury in Sediment ...... 3-146 3.4.3 Mercury in Aquatic Plants ...... 3-148 3 .4.4 Benthic Invertebrates ...... 3-150 3.4.4. t Lake Benthos Summary ...... 3-156 3.5 Beaver Lodge Survey ...... 3-156
4. Summary and Recommendations ...... 4-1 4. l Hydrology ...... 4-l 4.2 Ice Characterisation ...... 4-2 4.3 Fish ...... 4-4 4.4 Aquatic Biology & Chemistry ...... 4-6 4.5 Beaver Survey ...... 4-8
References ...... 1
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - x - Rescan"·' Environmental Services Ltd. (Proj. #664-1) Table of Contents
LIST OF APPENDICES
Appendix 2.1-1 - Hydrology Reconnaissance Survey Form
Appendix 2.1-2 - Hydrology Reconnaissance Video (July, 2003)
Appendix 3.1-1 - Details of Benchmarks Established, 2003
Appendix 3.1-2 - ADCP Flow & Cross-section Results
Appendix 3.2-1 - Glossary of Ice Terms
Appendix 3.2-2 - Ice Waypoint Coordinates
Appendix 3.2-3 - Water Temperature Profiles & Ice Thicknesses
Appendix 3.2-4 - Ice Survey Plates
Appendix 3.2-5 - Ice Survey Video
Appendix 3.3-1 - Sampling Location Coordinates for Gillnet Sets Conducted in the Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003
Appendix 3.3-2 - Minnow Trap Data Collected in Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003
Appendix 3.3-3 - Beach Seine Data for Taltson Lake and Taltson River, 2003
Appendix 3.3-4 - Fish Species Caught in 2003
Appendix 3.3-5 - Set and Retrieval Time, Catch-per-Unit-Effort, and Number of Fish Captured in Nonacho Lake with Experimental Gillnets, 2003
Appendix 3.3-6 - Set and Retrieval Time, Catch-per-Unit-Effort, and Number of Fish Captured in Taltson Lake with Experimental Gillnets, 2003
Appendix 3.3-7 - Set and Retrieval Time, Catch-per-Unit-Effort, and Number of Fish Captured in Rutledge Lake with Experimental Gillnets, 2003
Appendix 3.3-8 - Set and Retrieval Time, Catch-per-Unit-Effort, and Number of Fish Captured in Taltson River with Experimental Gillnets, 2003
Appendix 3.3-9 - Biological Characteristics of Fish from Nonacho Lake, 2003
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xi - Rescan"' Environmental Services ltd. (Proj. #664-1) Table of Contents
Appendix 3.3-10 - Biological Characteristics of Fish from Taltson Lake, 2003
Appendix 3.3-11 - Biological Characteristics of Fish from Rutledge Lake, 2003
Appendix 3.3-12 - Biological Characteristics of Fish from Taltson River, 2003
Appendix 3.3-13 - Fish Tissue Mercury Concentrations from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003
Appendix 3.3-14 - Stomach Content Data (by Numbers) of Lake Trout, 2003
Appendix 3.3-15 - Stomach Content Data (by Numbers) of Lake Whitefish, 2003
Appendix 3.3-16 - Deformities, Erosions, Lesions, and Tumours (DEL T) from Fish Captured within Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003
Appendix 3.3-17 - Parasite Incidence in Muscle Tissue from Fish Captured within Nonacho, Taltson and Rutledge Lakes, 2003
Appendix 3.4-1 - Physical Limnology Results from Nonacho Lake and Rutledge Lakes,2003
Appendix 3.4-2 - Physical Water Quality Results from Nonacho and Rutledge Lakes, 2003
Appendix 3.4-3 - Quality Assurance/Quality Control Results for Physical Water Quality from Nonacho Lake and Rutledge Lakes, 2003
Appendix 3.4-4 - Sediment Quality Results from Nonacho and Rutledge Lakes, 2003
Appendix 3.4-5 - Mercury Results for Aquatic Plants (Potamogeton sp.) from Nonacho and Rutledge Lakes, 2003
Appendix 3.4-6 - Taxonomic Results for Lake Benthos Density from Nonacho and Rutledge Lakes, 2003
Appendix 3.5-1 - Summary of Active Beaver Lodge Locations, Taltson, September - October 2003
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xii - RescanT" Environmental Services Ltd. (Proj. #664-1) Table of Contents
LIST OF FIGURES
Figure Page
1.1-1 Taltson Hydro Project General Location ...... 1-2
2.3-1 Sampling Areas for Fish, and Aquatic Biology and Chemistry, 2003 ...... 2-7
2.4-1 Nonacho Lake Aquatic Biology and Chemistry Sampling Locations, 2003 ...... 2-14
2.4-2 Rutledge Lake Aquatic Biology and Chemistry Sampling Locations, 2003 ...... 2-15
2.5-1 Aerial Beaver Survey Study Area, September-October 2003 ...... 2-21
3.1-1a Taltson Watershed (from Tsu Lake Outflow) Showing Main Sub-catchments ...... 3-2
3.1-1 b Ta Itson River System ...... 3-3
3.1-2 Environment Canada Rain Gauges within 100 km of the Ta Itson Watershed ...... 3-6
3.1-3 Locations of Active and Inactive WSC Gauges within the Taltson Watershed ...... 3-8
3.1-4 Fort Smith Mean Annual Air Temperature (°C), 1945-2001 ...... 3-12
3.1-5 Long-term Trends in Annual Precipitation, Rainfall and Snowmelt at Fort Smith Weather Station, 1943-2002 ...... 3-13
3.1-6 WSC Monthly Average Flows at Taltson River near Porter Lake (1974-1990) and Tsu Lake (1962-1997) ...... 3-19
3.1-7 Histograms of Peak Water Levels throughout the Year in the Ta Itson Watershed ..... 3-19
3.1-8 Examples of Annual Water Level Series for Nonacho Lake Illustrating Years where Peak Water Level Occurs during June/July ...... 3-21
3.1-9 Examples of Annual Water Level Series for Nonacho Lake Illustrating Years where Peak Water Level Occurs During September to November ...... 3-21
3.1-10 Discharges at Tsu Lake Outflow, the Taltson River at Porter Lake, and Outflow from Nonacho Lake ...... 3-22
3.1-11 Flows at Nonacho Lake Outflow and Downstream of Elsie Falls, 2001-2003 ...... 3-23
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xiii - Rescan"' Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.1-12 Hydrographs at the Tsu Lake Outflow and on Taltson River Downstream of Elsie Falls, 1994-1996 ...... 3-24
3.1-13 Nonacho Lake Water Levels, 1963-1976 ...... 3-26
3.1-14 Monthly Average Flows for the Tsu Lake Gauge, 1962-1997 ...... 3-27
3.1-15 Monthly Average Nonacho Lake Levels, '1969-1986 and 1987-2002 ...... 3-27
3.1-16 Peak Water Levels in No nacho Lake, 1968-2003 ...... 3-29
3.1-'17 Taltson River System: Great Slave to Tsu Lake Outflow ...... 3-31
3.1-18 Taltson River System: Tsu Lake Outflow to Twin Gorges ...... 3-33
3.1-19 Ta Itson River System: Elsie Falls to Upstream End of Trudel Creek ...... 3-34
3.1-20 Taltson River System: Twin Gorges to Tazin River ...... 3-35
3.1-21 Taltson River System: Tazin River to Lady Grey Lake ...... 3-37
3.1-22 Taltson River System: Lady Grey Lake to No nacho ...... 3-39
3.1-23 Water Surface Profile, August 2003 ...... 3-41
3.1-24 Rating Curves for One Open Gate at Nonacho Lake ...... 3-45
3.1-25 Rating Curves and Field Measurements for Nonacho Lake Spillway ...... 3-46
3.1-26 Rating Curves and Field Measurements for Leakage through Nonacho Dam ...... 3-48
3.1-27 Rating Curves and Field Measurements for Flow through Tronka Chua Gap ...... 3-48
3.1-28 Rating Equation Relating Power Production to Discharge through the Twin Gorges Generating Station ...... 3-50
3.1-29 Rating Equation for Flow Over the South Valley Spillway ...... 3-50
3.1-30 Twin Gorges Forebay Outflows and Flow at WSC Gauge Downstream of Elsie Falls ...... 3-52
3.1-31 Comparison of Calculated Twin Gorges Forebay Outflows and Observed flow at WSC Gauge Downstream of Elsie Falls for 2003 ...... 3-54
3.2-1 Ice Formation Process ...... 3-58
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3.2-2 Ta Itson River System and Reach Identification ...... 3-62
3.2-3 Reach 1 - Great Slave Lake to Tsu Lake Outflow ...... 3-63
3.2-4 Reach 2 - Tsu Lake Outflow to Twin Gorges ...... 3-65
3.2-5 Reach 3 - Elsie Falls to Upstream End of Trudel Creek ...... 3-66
3.2-6 Reach 4 - Twin Gorges to Tazin River ...... 3-67
3.2-7 Reach 5 - Tazin River to Lady Grey Lake ...... 3-69
3.2-8 Reach 5 - Lady Grey Lake to Nonacho Lake ...... 3-71
3.3-1 Fish Sampling Locations within Nonacho Lake and One Site on the Taltson River, 2003 ...... 3-82
3.3-2 Fish Sampling Locations on Taltson Lake, 2003 ...... 3-83
3.3-3 Fish Sampling Locations on Rutledge Lake, 2003 ...... 3-84
3.3-4a Fish Sampling Locations on the Taltson River, 2003 ...... 3-85
3.3-4b Fish Sampling Locations on the Ta Itson River, 2003 ...... 3-86
3.3-5 Percent of Fish Species Captured from Nonacho, Taltson, and Rutledge Lakes, and Taltson River, 2003 ...... 3-90
3.3-6 Average Catch-per-Unit-Effort from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-91
3.3-7 Length-Frequency Distributions for Lake Trout from Nonach, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-93
3.3-8 Length-Frequency Distributions for Lake Whitefish from Nonacho, Taltson and Rutledge Lakes, and Ta Itson River, 2003 ...... 3-94
3.3-9 Length-Frequency Distributions for Walleye from Taltson River, 2003 ...... 3-96
3.3-10 Weight-Length Regressions of Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-97
3.3-11 Weight-Length Regressions of Lake Whitefish from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-99
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation
Report - xv - Rescan TM Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.3-12 Weight-Length Regressions of Cisco, Northern Pike and Walleye from Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-100
3.3.13 Average Condition of Lake Trout and Lake Whitefish from Nonacho, Taltson and Rutledge Lakes, and Ta Itson River, 2003 ...... 3-101
3.3-14 Age-Frequency Distributions of Lake Whitefish from Nonacho, Taltson and Rutledge Lakes, and Ta Itson River, 2003 ...... 3-104
3.3-15 Age-Frequency Distributions of Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-105
3.3-16 Age-Frequency Distributions of Lake Cisco from Taltson and Rutledge Lakes, 2003 ·························································································································· 3-106
3.3-17 Age-Frequency Distributions of Northern Pike from Rutledge Lake and Taltson River, 2003 ...... 3-107
3.3-18 Age-Frequency Distributions of White Sucker from Ta Itson River, 2003 ...... 3-108
3.3-19 Age-Frequency Distributions of Walleye from Taltson River, 2003 ...... 3-109
3.3-20 Growth in Length of Lake Whitefish from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-112
3.3-21 Growth in Length of Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Ta Itson River, 2003 ...... 3-113
3.3-22 Growth in Length of Cisco from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-114
3.3-23 Growth in Length of Northern Pike from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-115
3.3-24 Growth in Length of White Sucker from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-116
3.3-25 Growth in Length of Walleye from the Taltson River, 2003 ...... 3-117
3.3-26 Regressions of Muscle Tissue Mercury Concentration on Body Length from Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-121
3.3-27 Regressions of Tissue Mercury Concentration on Body Length from Lake Whitefish from Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-122
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xvi - Rescan"·' Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.3-28 Plot of Muscle Tissue Mercury Concentration on Body Length of Walleye from Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ... 3-123
3.3-29 Average Length-Standardized Mercury Concentrations of Fish from Lake Trout from Nonacho, Taltson and Rutledge Lakes, and Ta Itson River, 2003 ...... 3-125
3.3-30 Number and Weight of Lake Whitefish Prey Items from Nonacho, Taltson and Rutledge Lakes, 2003 ...... 3-127
3.3-31 Number and Weight of Lake Trout Prey Items from Nonacho, Taltson and Rutledge Lakes, 2003 ...... 3-129
3.3-32 Regressions of Fillet Weight on Fork Length for Lake Whitefish and Lake Trout from Nonacho, Ta Itson and Rutledge Lakes, 2003 ...... 3-135
3.3-33 Cumulative Parasite Density in Muscle Tissue of Lake Whitefish and Lake Trout from Nonacho, Taltson and Rutledge Lakes, 2003 ...... 3-136
3.4-1 Secchi Depths for Nonacho and Rutledge Lakes, 2003 ...... 3-139
3.4-2a Dissolved Oxygen/Temperature Profiles for Nonacho Lake, 2003 ...... 3-141
3.4-2b Dissolved Oxygen/Temperature Profiles for Nonacho Lake, 2003 ...... 3-142
3.4-3a Dissolved Oxygen/Temperature Profiles for Rutledge Lake, 2003 ...... 3-143
3.4-3b Dissolved Oxygen/Temperature Profiles for Rutledge Lake, 2003 ...... 3-144
3.4-4 Conductivity for Nonacho and Rutledge Lakes, 2003 ...... 3-145
3.4-5 Total Dissolved Solids for Nonacho and Rutledge Lakes, 2003 ...... 3-147
3.4-6 Mercury in Sediment for Nonacho and Rutledge Lakes, 2003 ...... 3-149
3.4-7 Average Benthos Density for Nonacho and Rutledge Lakes, 2003 ...... 3-151
3.4-8a Average Taxonomic Composition of Lake Benthos Communities by Density for Nonacho and Rutledge Lakes, 2003 ...... 3-152
3.4-8b Average Taxonomic Composition of Lake Benthos Communities for Density for Nonacho and Rutledge Lakes, 2003 ...... 3-153
3.4-9 Average Lake Benthos Dipteran Diversity Indices for Nonacho and Rutledge Lakes, 2003 ...... 3-154
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xvii - Rescanm Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.4-10 Average Lake Benthos Taxonomic Richness for Nonacho and Rutledge Lakes, 2003 ...... 3-157
3.5-1 a Active Beaver Lodge Locations, Sept-Oct., 2003 ...... 3-158
3.5-ib Active Beaver Lodge Locations, Sept-Oct., 2003 ...... 3-159
LIST OF TABLES
Table Page
2.3-1 Fish Community Sampling Locations and Dates, 2003 ...... 2-6
2.4-1 Sampling Locations and Dates for Physical Limnology, 2003 ...... 2-13
2.4-2 Sampling Locations and Dates for Sediment, 2003 ...... 2-17
2.4-3 Sampling Locations and Dates for Aquatic Plants, 2003 ...... 2-18
2.4-4 Sampling Locations and Dates for Lake Benthos, 2003 ...... 2-'18
3.1-1 Sub-catchment Areas within the Taltson Watershed ...... 3-1
3.1-2 Areas and Perimeters of Major Lakes in the Taltson River system ...... 3-5
3.1-3 Environment Canada Weather Stations Near the Taltson Watershed ...... 3-7
3.1-4 Water Survey of Canada Water Level and Flow Gauges on the Taltson River System ...... 3-9
3.1-5 Long-Term Average Precipitation at Fort Smith Weather Station with Variation in Long-term Average ...... 3-14
3.1-6 Long-Term Average Rainfall at Fort Smith Weather Station with Variation in Long-term Average ...... 3-14
3.1-7 Summary of Long-term Average Snowfall at Fort Smith Weather Station with Variation in Long-term Average ...... 3-14
3.1-8 Periods of Weather Station Measurements at Nonacho Lake Lodge, Nonacho Lake ...... 3-15
3.1-9 Monthly Temperature (°C) at Nonacho Lake Lodge and Fort Smith ...... 3-16
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xviii - Rescan''"' Environmental Services Ltd. (Proj. #664-i) Table of Contents
3.1-10 Nonacho Lake Meteorological Station August to September 2003 ...... 3-i 6
3.1-11 Approximate Water Balance Calculations for Period 2001-2003 for Nonacho Lake and Twin Gorges Forebay ...... 3-18
3.1-12 Monthly Average Flows (m 3/s) at Tsu Lake Gauge, 1962-1997 ...... 3-28
3.1-13 Discharge Measurements Made during August 2003 ...... 3-42
3.2-1 Comparison of Freezing Degree Days to 25 November at Fort Smith ...... 3-53
3.2-2 Comparisons between Average Monthly November Flows and Water Levels and those during Freeze-up November 2003 ...... 3-55
3.3-1 Number of Gillnet, Minnow Trap and Beach Seine Hauls in Nonacho, Taltson and Rutledge Lakes and Taltson River, 2003 ...... 3-88
3.3-2 Fish Species Captured in Nonacho, Taltson and Rutledge Lakes and Taltson River, 2003 ...... 3-89
3.3-3 Number of Fish Captured in Minnow Traps from Nonacho, Taltson, and Rutledge Lakes and Ta Itson River, 2003 ...... 3-89
3.3-4 Average and Range of Fork Length and Weight of Lake Trout and Lake Whitefish Captured in Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-92
3.3-5 Average and Range of Fork Length and Weight of all Other Species Captured in Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-95
3.3-6 Average and Range of Condition Factor for Lake Trout and Lake Whitefish, 2003.3-102
3.3-7 Number of Aged Fish by Species and Lake, 2003 ...... 3-102
3.3-8 Average Ages of Fish from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-103
3.3-9 Sex Ratios of Lake Trout, Lake Whitefish and Walleye from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-111
3.3-10 Maturity Data for Lake Trout and Lake Whitefish from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-118
3.3-11 Lake Trout and Lake Whitefish Reproductive Status in Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-i 19
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xix - RescanrM Environmental Services Ltd. (Proj. #664-1) Table of Contents
3.3-12 Average Lengths and Tissue Mercury Concentrations for Fish from Nonacho, Taltson and Rutledge Lakes, and Taltson River, 2003 ...... 3-119
3.3-13 Number of Fish with Mercury Concentrations above the Health Canada Guideline. 3-120
3.3-14 Average Percent Fullness and Digestion of Fish Stomachs Collected from Nonacho, Taltson and Rutledge Lakes, 2003 ...... 3-126
3.3-15 Number and Percent of Fish in Nonacho, Taltson and Rutledge Lakes and Ta Itson River with Deformities, Erosions and Lesions, 2003 ...... 3-130
3.3-16 Number and Taxonomic Class of Parasites Found Infecting Lake Trout, Lake Whitefish and Walleye in Nonacho, Taltsbn, and Rutledge Lakes, and Taltson River, 2003 ...... 3-133
3.3-17 Average Density of the Parasite Triaenophorus crassus in Fish from No nacho, Taltson and Rutledge Lakes, 2003 ...... 3-134
3.3-18 Average Density of the Parasite Triaenophorus crassus in Fish from Nonacho, Taltson and Rutledge Lakes, 2003 ...... 3-137
3.4-1 Secchi Depth, Extinction Coefficient (k') and Euphotic Zone Depth for Nonacho and Rutledge Lakes, 2003 ...... 3-138
3.4-2 Mercury Results for Potamogeton sp. for Nonacho and Rutledge Lakes, 2003 ...... 3-148
3.4-3 Dipteran Diversity Indices for Lake Benthos, 2003 ...... 3-155
3.5-1 Number of Active and Abandoned Beaver Lodges (September-October, 2003) and Active Lodges ( October 2000) ...... 3-160
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xx - Rescan"•' Environmental Services Ltd. (Proj. #664-1) Table of Contents
LIST OF PLATES
Plate Page
2.1-1 Inflatable zodiac with ADCP ...... 2-3
2.1-2 Cross-section survey with safety line ...... 2-3
2.3-1 Stanley Beck pulling in a gillnet on Ta!tson lake ...... 2-8
2.3-2 Setting a minnow trap in Nonacho lake ...... 2-8
2.3-3 Pulling a beach seine on the Talston River...... 2-9
2.3-4 Internal visual examination of a lake trout...... 2-11
2.5-1 Active beaver lodge and food cache ...... 2-22
3.3-1 Taltson lake sampling site (Tl2) ...... 3-87
3.3-2 Taltson River sampling site - Fishing Hole Rapids (TR5) ...... 3-87
3.3-3 Taltson River sampling site (TR4) ...... 3-88
3.3-4 lake whitefish with a deformed caudal fin captured in Taltson River...... 3-131
3.3-5 Observed lesion on caudal fin of lake whitefish captured in Nonacho lake ...... 3-131
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xxi - Rescan"' Environmental Services Ltd. (Proj. #664-1) GLOSSARY
(ilescan)™ Glossary
ANCOVA ANalysis of COVAriance. A type of statistical analysis common in the biological sciences that partitions the variance of a data set into among-group, within group, covariate and error components, and then tests their relative magnitude as ratios of the error variance.
ANOVA ANalysis Of VAriance. A type of statistical analysis common in the biological sciences that partitions the variance of data into among-group, within-group and error components, and then tests their relative magnitude as ratios of the error variance.
Attenuation Reduction of the peak of a hydrograph by natural or artificial water storage. Typically refers to the broadening and flattening of a flood hydrograph, due to the effect of channel and lake storage.
Backwater A description of the upstream effect of a hydraulic control on a river, e.g. the backwater caused by the construction of Nonacho Dam affects water levels in the Taltson River for many kilometers upstream of the dam.
Barbel Tactile sensory appendage located on the lower part of the head near the mouth. Found on some species of fish that forage in turbid water or under low-light conditions (e.g., members of the cod and catfish families).
Benthic The bottom of a waterbody.
Benthos Animals that live attached or associated with the bottom of a waterbody.
Catchment Another term for watershed.
Cohort A group of organisms, usually of the same age, that travel though a population together. Originally, a Roman military unit of 600 soldiers.
Condition factor The ratio of wet body weight to the cube of body length. Used as an index of fatness or physical health of fish.
Covariate A variable that varies along with another variable (e.g., length and age). Its effect on other variables can be removed with ANCOVA.
Forebay In this report refers to the standing body of water upstream of a dam and which provides the hydraulic head for flow through a power generating station.
Fork length Length of a fish measured from the tip of the snout to the middle part of the tail (or caudal fin). Only used for fish with a forked tail.
Freshet flow High flows in a river as a result of the melting of ice and snow, usually at the beginning of spring.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xxii - Rescanr" Environmental Services Ltd. (Proj, #664-1) Glossary
Head Loss The difference in water level across a hydraulic structure, equivalent to a loss of energy across the structure.
Headwaters Furthest upstream, and topographically highest part of a watershed or catchment.
Hydraulic control Location on a river that strongly affects river water levels or flows upstream and downstream of that point. Can be man-made, (e.g. weir or dam) or natural (e.g. rapids, or waterfall).
Hydraulics In this report it refers to the study and physics of river flow.
Hydrograph Time series of river discharge at a point on a river.
Hydrometric data In this report it refers to all field measurements relating to rivers, including river flow data, river water level data, and river cross-section data. in situ Latin for "in place". Refers to experimental apparatus that are installed in natural ecosystems in order to replicate natural conditions as closely as possible.
Limnology The study of the physical, chemical and biological dynamics of lakes and of their plant and animal residents.
Littoral zone The shallow, sunlit part of a lake in which most of the biological production occurs. Most often found along the margins of a lake.
Lymphocystis Warty clumps on fish fins and body caused by a virus called Lymphocystis that enters the body through the mouth or through lesions in the skin.
Macrophyte Multi-cellular, rooted plants that live in streams or along the shallow shorelines of lakes.
Mysid A family of crustaceans (also known as shrimp). They hide in the substrate during the day and migrate into the water column at night to feed.
Neoplastic nodules Nodules of flesh made up of new, abnormal growth (i.e., a tumour).
Operculum The flap that covers the gills of modern or bony fishes.
Otic capsule The cartilaginous capsule surrounding the three pairs of otoliths.
Otolith An earbone. One of three pairs found in the heads of modern or bony fishes. The large sagittal otoliths are most commonly used for ageing purposes.
Phytoplankton Microscopic, single-celled plants that float freely in the water column.
Planktonic Small plants and animals that float in the open water column, and that typically never touch any surface.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report - xxiii - Rescan"'" Environmental Services Ltd. (Proj. #664-1) Glossary
Pneumatic duct A duct that links the swim bladder of some fish species with the digestive system.
Pressure transducer Measurement device that is submerged in water and that calculates water depth from the pressure of water acting on the device.
Reach (as in river) A section of a river, usually defined as being between two points, e.g. the reach of the Taltson River between Nonacho Lake and Lady Grey Lake.
River basin Another term for watershed.
Staff gauge Water level gauge.
Sub-catchment or The catchment of a tributary to a large river. For example, the Thoa River is a sub-watershed sub-catchment of the larger Taltson River catchment.
Tail race The discharging channel of a hydropower station.
Taxon A taxonomic unit (e.g., species, family, etc.). The plural is "taxa".
Thermocline The interface between two water layers with different temperatures. A place where temperature changes rapidly, typically greater than 1°C per meter.
Throttle points Control point along a river where flow is constricted through a narrowing of the river cross-section.
Tributary A smaller river that flows into a larger river, e.g. the Tazin River is a tributary of the Taltson River.
Watershed On a map it is the area that contributes runoff to a given point location. The point location depends on the purpose of study. For this report, we have defined a watershed from the outflow of Tsu Lake and refer to this area as the Taltson Watershed.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation
Report - xxiv - Rescan ,M Environmental Services Ltd. (Proj. #664-1) 1. INTRODUCTION
(]lescan)™ 1. Introduction
This report presents results of studies completed by RescanTM Environmental Services Ltd. (Rescan) in 2003 for the Water Effects Monitoring Program (WEMP) of the Taltson Hydro Project. The WENlP was developed and implemented in accordance with Water Licence N 1L4- 0154 for the Taltson Hydro Project, which is maintained and operated by the Northwest Territories Power Corporation (NTPC).
1.1 General
The Taltson Hydro Project is located on the Taltson River. 56 km north-east of Fort Smith. Northwest Territories (NT) (60° 25'N, 110° 24'W) (Figure 1.1-1). The 18MW hydro project was originally developed in l 965 to supply power to the Pine Point mine. Since that time, the project has received two major upgrades. ln 1968, a dam was constructed on Nonacho Lake to increase the storage capacity of the basin, along with three gates. and a spillway to regulate water storage. ln 1976, four small turbine generator sets were installed to expand the hydroelectric generating station by 4MW. Closure of the Pine Point mine in 1986 enabled the expansion of power supply to the communities of Hay River and Fort Fitzgerald, NT. Average generating output now ranges between 8 and l 2 J'vl W.
The main features of the Taltson Hydro Project are the Twin Gorges Generating Station and Forebay, the South Valley Spillway, the North Valley Perimeter dyke, and the Nonacho Lake control structure and spillway.
Comprehensive environmental baseline studies were not conducted for the Taltson Hydro Project prior to the hydroelectric constrnction. However. from 1977 to 1986 four studies were conducted to examine fisheries and hydrology related issues (Bogdan, l 977; Envirocon Ltd., 1973 and 1975; EnviroconPacific Ltd .. 1986). In 1999, the WEMP was developed by the NTPC in cooperation with regulators, and community stakeholders. The WEMP was developed to monitor the "short term, long term and cumulative changes within the water environment" (FSC, 1999). Since the development of the WEMP. three programs have been conducted. ln 2000. an aerial beaver survey was conducted (Rescan, 2000). In 200 I. an aerial muskrat survey was completed and a data compilation report for hydrology and meteorology was produced (Rescan, 200 la and 200 lb, respectively).
The WEMP was designed to monitor the potential aquatic effects associated with the operation of the Taltson Hydro Project. This program is referred as the routine program and a special effects monitoring program would be designed and implemented if the routine program concluded that unacceptable effects were detected. Before any effects can be detected. at least two years of data need to be collected.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 1-1 RescanT" Environmental Services Ltd< (Proj< #664-1) gis no. 664-5-24 Job No. 664-5 08/03/2004
N A
>r::h.,P ·~ Great Slave -. Lake
Northwest Territories
Alberta
1 :1,750,000 0 25 50
Kilometres
Projection: UTM12, NAD83
FIGURE: 1.1-1 PowER CORPORATION Taltson Hydro Project General Location Introduction
1.2 2003 WEMP
In 2003, Rescan was contracted by the NTPC to fully implement the WEtv1P. The WEMP includes two years of intensive biological and hydrological monitoring and data collection followed by regular monitoring. The 2003 year provides the first year of data for current conditions. The second year of data will be collected in 2004. The program will be reviewed and fine-tuned in tem1s of sampling sites, adequate sample size, sampling parameters and sampling frequency for the 2004 sampling season. These two years will form the basis for comparison to future monitoring. The monitoring program will then be conducted on a five year cycle to identity any effects starting in 2007.
Valued Ecosystem Components (VECs) and concerns with the environment were identified by the communities and regulators. A summary schedule of the proposed monitoring activities is provided in the WEMP document (FSC, 1999). The identified VECs that are required to be monitored are fish, aquatic plants, beaver (Castor canadensis), muskrat (Ondatia zibethicus), water levels and ice regime, ice related water level fluctuations and sedimentation and water level fluctuations. The VECs have been categorized into the following components for this report: hydrology, ice characterization, fish, aquatic biology and chemistry, and beaver lodge survey.
1.2.1 Program Objectives The general objectives of the 2003 WEMP were to collect biological and hydrological information on identified VECs to describe existing conditions and be able to detect changes in the future that may be attributable to the operation of the Taltson Hydro Project. These general objectives are the following:
Determining fish quality, abundance, size and feeding habitats;
Examining aquatic plant species for mercury uptake;
Determining the abundance of active beaver lodges;
• Examining water levels and ice characteristics;
Analysis of long-term flow records, both pre and post development; and
Studying water level fluctuations.
Below is a description of the specific objectives of each component of the 2003 WEMP.
1.2.1.1 Hydrology The following specific objectives of the 2003 WEMP provide the basis for the long-tem1 general objectives presented in Section l .2.1 :
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 1-3 Rescann., Environmental Services Ltd. (Proj #664-1) Introduction
identify key hydraulic controls. lakes with large routing capacity. and representative cross-sections of uniform reaches along the Taltson River system through detailed reconnaissance by helicopter;
measure water levels along the Taltson River system from Nonacho Lake to the outflow of Tsu Lake:
establish benchmarks on the shore/bank of the Ta Itson River so that future water levels can be monitored relative to these benchmarks; and
collect cross-section and flow data at key locations along the Taltson River.
1.2.1.2 Ice Characterisation The objectives of the ice characterisation work were to observe and document the freeze-up processes so as to obtain an understanding of the cun-ent ice processes along the Taltson River System. As part of this objective, water temperatures and ice thickness measurements were to be collected during the freeze-up period.
1.2.1.3 Fish The specific objectives of the fish component for the WEMP were to develop a fish database with the capacity to identify changes to the fish community over time. The WEMP focused on three fish species of interest; lake trout, lake whitefish, and walleye. Lake trout and lake whitefish are the most abundant species in the Taltson Watershed. They are fished by locals and are an important food source. Walleye is also fished by locals. but is only found in the Taltson River. Lake trout and walleye are at the top of the food chain and thus integrate changes occurring lower in the food web. Therefore, monitoring of these two species serves as a measure of the integrity of the aquatic ecosystem. Data on other fish species such as no1thern pike, burbot and suckers were collected on an opportunistic basis (when captured) because of their lower abundance and their lower importance to local consumers.
The fish variables selected for this report was based on the VECs defined in the WEMP and concerns identified during consultation. The identified variables were fish quality (health, parasite load and mercury contamination), fish abundance, fish size distribution, and feeding habits for fish.
Mercury levels and contamination in fish are a concern especially when fish are used for human consumption; therefore, fish muscle tissue were analyzed for mercury concentrations. Parasite levels in flesh of certain species (lake whitefish and lake trout) provided information on current conditions and will contribute to future monitoring of the level of parasites in fish. Fish deformities, erosions. lesions and tumours were also monitored to provide information on the health and quality of the fish within the four waterbodies studied.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 1-4 RescanT'·' Environmental Services Ltd. (Proj. #664-1) Introduction
Fish abundance data also provide an opportunity to monitor future fluctuations due to changes in reservoir operation. Fish size distribution and condition indicate the robustness of the fish and will address concerns pertaining to skinny fish. Age and growth data provide information as to whether the population structure is remaining constant and indicate whether ce1iain years are associated with low reproductive success or poor growing conditions that may be related to the project. Fish stomach content information provide the basis upon which potential diet changes as a result of future changes in operation may be assessed. An inadequate diet can lead to poor fish condition and ultimately a smaller population due to lower survival and growth.
Any historical data from the Taltson Watershed on fish, and aquatic biology and chemistry will be reviewed in early 2005 in conjunction with the 2003 and 2004 dataset.
1.2.1.4 Aquatic Biology and Chemistry As paii of the requirements for the WEMP, various non-fish variables had to be sampled. These variables included physical limnology (transparency, Secchi depths, dissolved oxygen and temperature), conductivity, total dissolved solids, sediments and aquatic plants for mercury analysis, and benthic invertebrates.
Water quality may be affected by changes in water level and fiow rates as a result of addition of suspended solids, nutrients and changes in water retention time. Therefore, transparency, dissolved oxygen, water temperature and conductivity (as an approximation of total dissolved solids) were sampled at all sampling locations in order to develop a water quality database.
Mercury is released from sediments during flooding and has been identified as a concern during consultation. Measuring mercury in sediments of a reservoir provides an indicator of the historical exposure of fish to mercury contamination.
Aquatic plants were identified as a VEC and as one of the concerns during consultation. Moose consuming aquatic plants at risk to elevated levels of mercury are susceptible to bio accumulation of mercury in the muscle tissue. Monitoring the level of mercury in aquatic plants in shallow littoral zones allows for the assessment of changes observed in the future due to reservoir operation.
The monitoring of the benthic invertebrate community (fish food) provides a basis for detecting changes in the food supply for fish that may result from future operational changes should they occur. Benthic inve1iebrate data were collected from selected littoral and deepwater habitats.
1.2.l.5 Beaver Survey Monitoring of beaver populations was initiated in fall :woo (Rescan, 2000 ), with the objective of determining the abundance and distribution of beaver lodges in areas identified during development of the WEMP. Objectives of the 2003 fall beaver lodge survey were to determine and compare abundance and distribution of beaver lodges in the areas examined during fall 2000.
March 2004 2003 Waier Effects Monitoring Program Northwest Territories Power Corporation Report 1-5 Rescanrn Environmental Services ltd, (Proj, #664-1) Introduction
1.3 Study Areas
The following study locations were identified in the WEMP and included as patt of the 2003 scope of work:
Nonacho Lake: represents conditions within the reservoir. Nonacho Lake supports a fishing lodge. is used by residents of Lutsel K'e. and was once used for a commercial fishery:
Taltson Lake: represents conditions immediately downstream of the reservoir. Taltson Lake is affected by changes in seasonal discharge from Nonacho Dam. Taltson Lake supports a sport fishery, and at one time a commercial fishery:
Rutledge. Porter and Hanging fee lakes and Tethul River: represent conditions in a natural area, these lakes and river are unaffected by both the Twin Gorges Generating Station and Nonacho Lake; Rutledge Lake supports a sport fishery; and
Taltson River: Taltson River is affected by daily flow changes from Twin Gorges and seasonal changes from the Nonacho Darn. Taltson River is used for recreation, suppotts a sport fishery, and is used by local hunters and trappers.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 1-6 Rescan"·' Environmental Services Ltd. (Proj. #664-1) 2. METHODS
(itescan)™ 2. Methods
The research team used 1:50,000 scale National Topographic Survey (NTS) maps while conducting the 2003 field work. All maps and map based figures presented in this report are based on Canfvlatrix (Geo TIFF) 1:50,000 and l :250,000 scale maps. The CanMatrix maps were purchased for this project from the Centre for Topographic Tnfom1ation in Sherbrooke, Quebec. These maps, together with a digital 1: L000,000 scale waterbody map of Canada, formed the basis of the Geographic Information System (GlS) input to this project.
The following section details the methods used for the 2003 field component of the WEMP.
2.1 Hydrology
The methods used to collect hydrological data for the Taltson Watershed were chosen to meet the specific objectives stated in Section 1.2.1.1.
A number of specific tasks were required to meet the hydrology objectives. A reconnaissance survey was conducted to identify key hydraulic controls, routing potential and representative cross-sections of uniform reaches. A GPS survey was undertaken to establish shore/bank benchmarks and measure current water levels. Flows and cross-sectional data were also collected. Below is a detailed description of the methods used to complete each task.
2.1.1 Reconnaissance A reconnaissance survey from Ta!tson Bay on Great Slave Lake to Taltson River at Porter Lake was undertaken by helicopter by three members of the research team from July l O to 12, 2003. The survey was conducted in a helicopter at low level. The research team investigated key locations in detail by landing near each site and completing a reconnaissance survey form (Appendix 2.1-1 ). The fonns were not filled out in their entirety for each location but were used as a guide for data collection. Key sections of the river were photographed and a video camera was used to document the entire aerial and land survey (Appendix 2.1-2).
2.1.2 GPS Survey The main objective of the GPS survey was to establish shore/bank benchmarks at key locations along the Taltson River. The second objective was to collect current water level data while the GPS equipment was at hand. The purpose of the benchmarks is to use them to obtain future water levels without using GPS equipment. During future surveys, a line-of-sight level can be used to determine the difference in elevation between the benchmarks and future water levels. Given that the absolute elevation of the benchmark is known, these water levels can easily be tied into other water levels along the Taltson River. Moreover, a staff gauge equipped with a
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-1 Rescanm Environmental Services Ltd. (Proj. #664-1) Methods pressure transducer installed near the benchmark and then surveyed to the benchmark will provide continuous absolute water levels.
The OPS survey used Real Time Kinematic (RTK) survey equipment by Trimble. The OPS equipment consisted of a base unit (station or location with known coordinates) and a rover unit (station or location with unknown coordinates). Each unit, base and rover, consisted of a Trimble 5700. One was configured as the base and the other configured as the rover. The base unit included a radio transmitter and the rover used a radio receiver. The radio equipment was made by Pacific Crest (LS 35).
To begin the OPS survey, the base station was setup on a known point (579053) from Geological Survey of Canada (GSC). The rover was then transported by helicopter to the desired location near the Taltson River. The distance between the base and rover stations was limited by radio communication between the two stations. An RTK survey requires constant radio communication to determine a precise location of the rover. The maximum distance between the stations varies, as the topography of the area of study can significantly reduce the communication distance between stations. The typical distance in an area of uniform topography was between 5 and l O km. Once the rover station established a location, the base station was retrieved and setup at the new known location. This process of 'leap-froging' stations continued until high-level benchmarks were established from the outflow of Tsu Lake to the Nonacho Lake.
The second phase of the survey was to use the high-level benchmarks to establish shore/bank benchmarks at key locations along the Taltson River. The base station was setup at the closest high-level benchmark and the rover was positioned at a key location approximately 2 m above the ctment water level. Prior to setting up the rover semi-permanent markings were made so the benchmark could be used in subsequent surveys. Spray paint was used to visually indicate the location of a benchmark. After the shore/bank benchmark was established, the OPS equipment was used to detennine the cunent water level near the benchmark.
A total of 35 high level and 41 shore/bank benchmarks as well as 43 water levels were established during the 2003 field season. The survey crew consisted of one scientist and one local assistant.
2.1.3 Flows & Cross-sections: ADCP The objective of the flow and cross-section work was to begin the process of data collection for use for a future flow model of the Taltson River. Key locations identified during the reconnaissance survey were chosen for detailed data collection. At each location. an Acoustic Doppler Cunent Profiler (ADCP) was used to obtain cross-section details; river bed depth with distance from banks. horizontal velocity profiles. total flow measurement and flow measurements for various sections across the river.
The ADCP used for the flow and cross-section work was RD fnstruments' 600 kHz Rio Grande. The ADCP was mounted on an 11 foot inflatable Zodiac powered by a 6 HP two-stroke motor (Plate 2.1-1 ). The intlatable Zodiac was used due to its easy transport. A temporary safety line
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-2 Rescan"'·' Environmental Services ltd. (Proj. #664-1) Methods was secured across the river to help maintain a perpendicular trajectory, slow and steady collection of data and direct contact with the bank if complications occurred (Plate 2.1-2). For each cross-section, a minimum of two surveys were conducted.
Plate 2.1-1. Inflatable zodiac with ADCP.
Plate 2.1-2. Cross-section survey with safety line.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-3 RescanT" Environmental Services Ltd. (Proj. #664-1) Methods
The particular ADCP used (600 kHz Rio Grande) requires a minimum of 1.5 rn of water to record accurate depth and velocity measurements. The distance from the banks to a water depth of l .5 m varied for each cross-section and had to be measured prior to data collection. The flows in these unmeasured sections were approximated by the ADCP software using the velocity and depth measurements at i.5 m, the distance to the bank. and the flow equation.
2.1.4 Taltson Local Datums There are a number of local site datums that have been established for the Taltson Hydro Project; Nonacho Lake water level, Nonacho Spillway sill, gates at Nonacho Dam, Tronka Chua Gap sill, Twin Gorges forebay levels, South Valley Spillway sill, and WSC 07QD007 (Taltson River downstream of Elsie Falls. During the 2003 field season, an RTK-GPS survey was completed to convert all these local datums to metres above mean sea level. denoted as metres above sea level (mas!).
Nonacho Lake water levels are measured relative to a gauge datum giving values typically of the order of 5 to 7 m. This datum is refened to as Nonacho Lake Gauge Datum (NLGD). NTPC conve1i these gauge values into a local datum that approximates the water level on Nonacho Lake in metres above sea level (mas!). This datum is referred to as Nonacho Lake Local Datum (NLLD). The relationship between the two datums is NLGD = NLLD + 314.62 m. On August l2. 2003. the water level of Nonacho Lake was measured. Comparing this measurement to the recorded water level at the Nonacho Lake gauging station. a relationship between the two datums was obtained; NLLD (mas!) =NLLD (m) +2.41 m.
For this report, it has been assumed that all NTPC established datums (Nonacho Spillway sill, gates at Nonacho Dam and Tronka Chua Gap sill) required the same correction factor of +2.41 rn. Thus, the former sill elevation ofNonacho Spillway of 320.04 mis presented as 322.45 masl; the former sill elevation of the gates at Nonacho Dam of 317.30 m is presented as 319.71 mas!; the former sill elevation of the Tronka Chua Gap of 320.20 m is presented as 222.61 masl. It should also be noted that the elevation at which leakage through the dam begins has also been adjusted in this report from 317 .0 to 3 l 9 .4 l mas!.
Water levels at Twin Gorges forebay are measured and to a local datum that approximates meters above sea level (masl). This datum is referred to as Twin Gorges Gauge Datum (TGGD). On August 3, 2003, the vvater level in the Twin Gorges forebay was measured. Comparing this measurement to the recorded water level at the Twin Gorges forebay gauging station, a relationship between the two datums was obtained; TGGD (masl) = TGGD (m) + 8.43 m. For this report, it has been assumed that the sill elevation of the South Valley Spillway required that same +8.43 m correction. Thus, the former sill elevation of the South Valley Spillway of 239.37 mis presented as 247.70 mas!.
The WSC gauge station downstream of Elsie Falls (WSC 07QD007) is measured to the WSCs own datum. During the 2003 field season no field measurements were made close to the gauge
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation 7 Report 2-4 Rescan M Environmental Services Ltd. (Proj. #664-1) Methods site and as a result the relationship betvveen the WSC datum and metres above seal level (mas!) was not calculated. Hence, the WSC gauge values are used in this report.
2.2 Ice Characterisation
Ice characterisation component of the 2003 WEMP included a detailed survey of the freeze-up process of the Taltson River from Taltson Bay on Great Slave Lake to Nonacho Dam. During the survey, ice thickness and water temperature data were collected at key locations along the survey route.
Information gathered during the survey consisted of:
Visual observations of the freeze-up process including video taping the river between Great Slave Lake and Nonacho Lake and photographing key areas; and
• Taking water temperature profiles and ice thicknesses at key locations.
2.2.1 Freeze-up Process Survey Observations and water temperature measurements were carried out on the Taltson River from 25-27 November. 2003. operating out of the Twin Gorges Generating Station with a helicopter.
The freeze-up survey period was planned to occur when between 200 to 300 freezing degree days of cold (DD<0°C) had been reached and the air temperature was -i0°C or less. From past experience, good freeze-up observations are nom1ally achieved when these conditions have been met. The air temperatures and number of freezing degree days at Fort Smith and Yellowknife were carefully monitored so that observations could be made within this window.
Visibility during the survey period was generally very good with clear skies and a few clouds in the upper reaches of the Taltson River. Visibility decreased however close to the Great Slave clue to the presence of open water and higher humidity.
2.2.2 Ice Thickness Measurements lee thicknesses were measured by drilling a hole in ice and obtaining the thickness with a rigid rod equipped with a graduated scale and a hook at the bottom. The hook was inserted under the bottom of the ice and thickness vvas measured from the scale.
2.2.3 Water Temperature Profiles Water temperature profiles were obtained using a calibrated electronic thermistor (precision ± 0.0 I °C) and an ohmmeter. attached to 30 rn of cable graduated in 1 m increments. Once the hole had been cut in the ice and the thickness measured, the thennistor was lowered to the river bed
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-5 Rescan'" Environmental Services Ltd. (Proj. #664-1) Methods and the depth was measured. The ohmmeter reading was read once it had stabilized and again in 1 m increments from the surface as it was raised.
2.3 Fish
2.3.1 Sampling Program In July, August and September 2003. a fish sampling program was carried-out within the Taltson Watershed including three lakes (Nonacho, Taltson and Rutledge) and the river itself. These waterbodies were selected for monitoring as part of the WEMP. The methodology used in 2003 was based on the study design proposed in the WEMP. All sampling areas ,vithin those waterbodies are outlined in Figure 2.3-1. The sampling dates and waterbodies for the first year of data collection are presented in the following table (Table 2.3-l).
Table 2.3-1 Fish Community Sampling Locations and Dates, 2003
Summer 2003 Fall 2003 Nonacho Lake August 1 - 3, August 7 September 19 - 21 Ta Itson Lake August 3-6 September 20 Rutledge Lake August 4- 7 September 19 - 21 Taltson River July 30 - August 2 September 19
Three techniques were used to sample fish populations:
Experimental gillnets: this is a sinking gillnet that measures 160.3 m long and 1.83 m deep. It has seven panels of different mesh sizes: 2.5, 3.8. 5.L 7.6, 9.5, 10.8, and 12.7 cm 2 stretched mesh. The total surface area of an experimental gillnet is 293 m • Gillnets were set both parallel and perpendicular to shore. The location and depth of each net was recorded with a hand-held GPS unit and a hand-held depth sounder, respectively. Nets were set in various depth regimes to ensure a wide range of fish species and size distributions were sampled. Set and retrieval times of gillnets were also recorded. Nets were set for a short period of time (approximately 1 hour) to minimize mortality (Plate 2.3-1 ):
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-6 RescanrM Environmental Services ltd. (Proj. #664-1) gis no. 664-5-13 Job No. 664-5 04/03/2004
1:1,500,000 0 25 c:::=.::::::.::_ ::::=::: ______------] Kilometres
Projoclion: UTM12, NAD83
FIGURE 2.3-1 uonmvit?STTERflffom1a; POWER CORPORATION Sampling Areas for Fish, and Aquatic Biology and Chemistry, 2003 Methods
Plate 2.3-1. Stanley Beck pulling in a gillnet on Taltson Lake.
Minnow traps: these traps have a conical shape and measure 40 cm long with a 20 cm diameter and are made of metal with 7 mm mesh. Traps were baited with dry dog food, or cat food and placed in areas of shallow water depth (<1 rn) (Plate 2.3-2). The location of each trap was recorded with a hand-held GPS unit, and the traps were marked with a buoy. Traps were left for varying periods of time, ranging from 2.5 hrs to 20 hrs. Times of deployment and retrieval were recorded;
Plate 2.3-2. Setting a minnow trap in Nonacho Lake.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-8 Rescann,, Environmental Services ltd. (Proj, #664-1) Methods
• Beach Seine: this smalL fine-mesh seine net was used to sample the littoral zone. The seine measured 15.2 m long, l.3 m deep with 3 mm wide mesh. The net was swept over short sections of shoreline and then pulled to shore (Plate 2.3-3).
Plate 2.3-3. Pulling a beach seine on the Talston River.
All captured fish were identified to species, counted, and their fork length and wet weight were measured to the nearest 1 mm and gram, respectively. Scales, fin rays, or spines were collected from each fish. Approximately 3 to 5 scales were obtained from the left dorsal area of the fish with a clean pair of tweezers. A pair of pliers was used to collect 2 to 3 fin rays from the left pelvic fin of all fish, with the exception of walleye where two to three spines were taken from the dorsal fin. All scales, spines and fin rays were sent to North Shore Environmental Services Ltd. in Thunder Bay. ON, for age determination. Age was determined by counting the number of annuli or rings on the aging structure. Scales were attached to plastic fiches, and annuli were counted with a microfiche reader. Fin rays and spines were air-dried and then mounted in a 50:50 epoxy medium. Microsections were cut using a Beuller Tsonet diamond saw and mounted on slides to enable a count of the annuli using a compound microscope.
According to the WEMP, all captured fish were to be examined externally for deformities, erosions, lesions and tumours (DELT). Deformities were defined as any of the following: deforn1ed fin, head, vertebrae, barbel or other body patt. Erosions on fins, gill covers, tail, or barbel as well as fin or gill rot were evaluated. Fish lesions were defined as open sores, exposed tissue, ulcerations. cysts or other lesions. Any external visible tumours were identified, tumours were defined as neoplastic nodules and lymphocystis. Representative DEL Ts were photographed.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-9 Rescanm Environmental Services Ltd< (Proj< #664-1) Methods
A subset of lake trout, lake whitefish and walleye from a range of size classes were sacrificed and the following parts collected: otoliths (for ageing), stomachs (for diet analysis), fillets (for parasite analysis), and muscle tissue (for mercury analysis). This subset was also examined internally for general health, such as the presence of growths and parasites (Plate 2.3-4). All internal parasites were listed in the comments section of the field data sheets. Once the body cavity was opened, the reproductive organs were examined to determine gender, maturity and reproductive status. Reproductive status was classified based on the following categories: unknown. undeveloped. green (maturing), ripe (mature and ready to spawn), running (spawning) and spent (has already spawned in the cuITent year).
Otolith samples were removed from the otic capsule once the head was opened. Tweezers were used to carefully remove up to two otoliths from each fish. The otoliths were cleaned and placed into envelopes labelled with the date. species, sampling location and the sample number. All otolith samples were sent to North Shore Environmental Services Ltd. for age detem1ination. Otoliths were air-dried, cracked and burned over a flame to make growth rings more visible. They were subsequently mounted in Plasticine and immersed in oil to allow the growth rings to be viewed under a microscope. When multiple aging structures are collected for fish sampling, otolith samples have typically shown the most reliable results.
Stomachs were removed from the fish body cavity and placed into labell,;;;d W11irl-Pak bags. Samples were preserved in 10% buffered formalin and shipped to Applied Technical Services Ltd. in Victoria, B.C., for analysis. Stomach samples were analyzed for percent fullness, stomach contents were weighed and all prey items were identified to the lowest taxonomic level possible.
Myomere (muscle) tissue samples (5 to 20 grams) were taken from the posterior region of the left dorsal area with a clean filleting knife. The samples were placed in labelled Whirl-Pak bags and stored in a cooler. Samples were sent to ALS Environmental in Vancouver, BC, and kept frozen until analysis could be completed. All samples were homoginized using stainless steel hand tools. and analysed for mercury.
Once a sample of muscle was taken for mercury analysis, each fish was filleted and all muscles were collected for parasite analysis. The wet weight of the fillets were recorded in the field and the fillets vvere placed into a large labelled zip-lock bag. The species, sample number, sampling location and date were recorded on each zip-lock bag. Fillets were stored frozen and shipped in a cooler to Applied Technical Services Ltd. for analysis. Once in the lab, the number of Triaenophorus crassus parasites were counted.
All field data were entered onto paper data sheets in the field and later entered into an electronic MS-Excel spreadsheet in the office.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-10 Rescanrn Environmental Services Ltd. (Proj. #664-1) Methods
Plate 2.3-4. Internal visual examination of a lake trout.
2.3.2 Data Analysis The fish communities were characterized using the relative species abundance, catch-per-unit effort (CPUE), length-frequency distributions, age-frequency distributions, growth curves, weight-length regressions, sex, maturity, reproductive status, diet, mean length, mean weight. mean age, mean condition, mercury concentrations in muscle, diet, parasites, deformities erosions, lesions and tumours. Descriptions of some of the analyses are described below.
Determining the exact number of fish in a given lake is difficult however, CPUE is a good estimate. Catches were converted to CPUE in order to be comparable to catches of different lengths of time and between lakes. CPUE was defined as the number of fish captured per gill net per unit of time and area. Gill net CPUE was calculated as:
2 ( l) CPUE = (Number of fish)( l 00/ total area of net in 111 )(24 hrs/set time in hours)
CPUE has units of fish/I 00 m2/day. CPUE were not calculated for minnow trap and beach seine daJa because only a few fish were captured with this method.
The relationship between weight and length of fish is exponential m nature and so it was described by the linear regression equation:
(2) ln(weight, g) = ln(a) + bln(fork length, mm)
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-11 Rescan r,, Environmental Services Ltd" (Proj" #664-1) Methods where a is the coefficient, b is the slope of the regression.
The physical condition of a fish (i.e .. fatness) was determined by the ratio of weight to length cubed (Ricker. 1975):
(3) Condition= (weight (g) x 105)/(length, mm)3
Growth was described using the von Bertalanffy growth model, the standard model used m fisheries science (Ricker. 1975):
(4) Lt= C,,(l - exp(-K(t-t1)))
Lt= the length (mm) at age t (years), asymptotic length (mm) (length at infinite age), K 1 growth coefficient (years- ) and t0 = age (year) at L = 0 mm.
All statistical analyses were conducted with the SYSTAT library of computer programs (SPSS, 2 1998). All regressions used in this study used a coefficient of determination (r ) that was adjusted for the number of degrees of freedom of the regression. All regressions were accompanied by the probability (P) that the result was obtained in error. Transformation of certain variables with natural logarithms was necessary in order to meet the requirements of regression (Zar, 1984). The two principal requirements are that the independent variable and dependent variable both be normally distributed and that both have constant (or homogeneous) variances throughout their ranges.
2.3.3 Quality Assurance/Quality Control (QA/QC) All field data was transcribed onto electronic excel spreadsheets. The electronic spreadsheets were visually compared to the field sheets to minimize errors. The length and weight data were plotted, and outliers examined for possible transcription, or recording enors in the field. Sub sampled fish were aged with multiple aging structures (scale, spine, otolith, and fin ray) to ensure accurate age determination. Once in the lab. all biological samples (stomach, fillet tissue sample, scale, otolith, fin rays, and spines) were organized and checked against the electronic spreadsheets.
2.4 Aquatic Biology and Chemistry
2.4.1 Sampling Program Two lakes (Nonacho and Rutledge) were selected for the aquatic sampling program. Rutledge Lake represents a non-impacted lake and was selected based on factors such as similarity to Nonacho Lake in tenns of species assemblage, physical and morphological features, shoreline characteristics, accessibility and availability of support facilities. Sampling locations were selected to represent potentially different biological and chemical characteristics within each
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-12 Rescan"' Environmental Services Ltd. (Proj. #664-1) Methods lake. Three sites were selected in each lake and were referred as site L 2 and 3. At each of these sites, a shallow and deep station was sampled for a total of 6 stations per lake. The sampling collection and processing procedures for each variable is discussed below.
2.4.1.1 Physical Limnology Physical limnology (Secchi depth and dissolved oxygen/temperature profiles) and water quality parameters were collected at 12 stations in 2 lakes (Nonacho and Rutledge) vvithin the Taltson Watershed. Table 2.4- l presents the sampling stations, locations and dates that physical lirnnology data were collected. Sampling locations are presented in Figures 2.4-1 and 2.4-2.
Table 2.4-1 Sampling Locations and Dates for Physical Limnology, 2003
Northing Easting Water Quality Lake Station (m) (m) Date Depths (m) Nonacho Lake NL 1-Shallow 6840874 0569306 1-Aug-03 1 NL 1-Deep 6841108 0569827 1-Aug-03 1, 13 NL2-Shallow 6841920 0559854 2-Aug-03 1 NL2-Deep 6842031 0559815 2-Aug-03 1, 15 NU-Shallow 6845240 0573398 3-Aug-03 1 NL3-0eep 6845323 0573643 3-Aug-03 1, 15 Rutledge Lake RL 1-Shallow 6830155 0512019 4-Aug-03 1 RL 1-0eep 6830761 0511757 4-Aug-03 1, 15 RL2-Shallow 6834725 0507524 5-Aug-03 RL2-Deep 6833835 0508075 5-Aug-03 1, 15 RL3-Shallow 6827764 0513557 6-Aug-03 1 RL3-Deep 6827926 0513387 6-Aug-03 1, 19
Secchi Depth Secchi depths were collected from all 12 stations within Nonacho and Rutledge lakes. Sampling locations and dates are presented in Table 2.4-l. The Secchi depths from both Nonacho and Rutledge lakes were determined through the use of a standard 20 cm black and white Secchi disk. The Secchi disk is used to detennine an extinction coefficient of light within the water column, which in turn is used to determine the depth of the base of the euphotic zone (the water column above the depth at which 0.1 % of surface irradiance penetrates). The euphotic zone represents the upper sun! it water column where photosynthesis can occur.
March 2004 2003 Water Effects Monitoring Program Northwest Territories Power Corporation Report 2-13 Rescan n., Environmental Services Ltd, (Proj, #664-1) gis no. 664-5-14a Job No. 664-5 08103/2004
Physical Limnology, Lake Benthos o S = Shallow Sampling Sites • D = Deep Sampling Sites
o Aquatic Plants • Sediment NL2-D (a)fll NL2-D (b) 1:60,000 0 1,000 2,000
O NL2-S (b) NL2-S (a) 0 ~ •, Metres Projection: UTM12, NAD83
(a)= Difficulty obtaining lake benthos samples. Samples collected al station (b) instead. (b) = Lake benthos samples only. 10,000 NL = Nonacho Lake
HORTHWEST TERfUTOO!E$. FIGURE 2.4-1 POWER Nonacho Lake Aquatic Biology and CORPORATION Chen1istry Sampling Locations, 2003