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Spillimacheen Project Water Use Plan
Assessment of Rampdown Duration to Minimize River Stage Change During Full Plant Outages
Reference: SPNMON-1
Final Report
Study Period: 2009
M. McArthur, G. Martel, J. Berdusco, M. Marrello BC Hydro, Environmental and Social Issues
May 10, 2010 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Assessment of Rampdown Duration to Minimize River Stage Change During Full Plant Outages (SPNMON-1)
M. McArthur1, G. Martel1, J. Berdusco2 and M. Marrello3
May 10, 2010
Authors affiliations: 1. Environmental and Social Issues, BC Hydro, Burnaby, BC 2. BC Hydro, Cranbrook, BC 3. BC Hydro, Castlegar, BC
BC Hydro Page 2 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Table of Contents
Introduction ...... 8 1.0 Background ...... 8 1.2 Description of Operations...... 10 1.3 Objective ...... 11 1.4 Management Questions ...... 11 1.5 Management Hypothesis...... 11 2.0 Methods...... 12 2.1 Approach ...... 12 2.2 Literature Review ...... 12 2.3 Field work ...... 13 2.4 Analyses...... 17 3.0 Results ...... 17 3.1 Literature Search...... 17 3.2 Stage monitoring ...... 21 4.0 Discussion...... 35 5.0 Recommendations ...... 39 Literature Cited...... 40 Acknowledgements...... 43 Appendix I Habitat Photos………………………………………………………………………
BC Hydro Page 3 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
List of Tables
Table 1. Operational constraints for planned outages for Spillimacheen generation flows...... 10 Table 2. Sources and search terms used for collection of information during the literature review, Spillimacheen rampdown rate study...... 12 Table 3. Spillimacheen River sampling stations descriptions. Refer to Figure 2 for stations locations. Start and end dates & times apply to level loggers only...... 16
List of Figures
Figure 1. Location of Spillimacheen Generating Station ...... 9 Figure 2. Approximate location of stations for Spillimacheen monitoring study...... 15 Figure 3. Transects at Stations 3 (left) and 4 (right) in side channels adjacent to the Spillimacheen River, October 22, 2009. Refer to Figure 2 for locations...... 17 Figure 4. Water discharge data from the Spillimacheen River, October 19 to October 25, 2009. Data from WSC station # 08NA011. Red circle encloses the approximate duration of the rampdown study...... 22 Figure 5. Water Survey Canada data for the Spillimacheen River (Station 1, Figure 2) on October 22, 2009...... 22 Figure 6. Spillimacheen water levels and temperatures recorded by level loggers at Stations 1-3, October 21-22, 2009. Bars and shaded areas indicate duration of rampdown. Refer to Figure 2 for locations of stations...... 27 Figure 7. Staff gauge water levels of Spillimacheen side channels (lines are substations, m from left bank), Stations 4 and 3, measured on October 22, 2009. Dashed lines enclose rampdown duration...... 28 Figure 8. Water temperature and level for the Kootenay River at Fort Steele WSC gauge, October 19-25...... 29 Figure 9. Water and air temperature for the Kootenay River at Fort Steele WSC gauge, October 19-25...... 29 Figure 10. Air and water temperature for the Kootenay River at Fort Steele WSC gauge, October 21-23, 2009. Note that axes are different from Figure 8...... 30 Figure 11. Wetted widths for Spillimacheen sampling transects, October 22, 2009...... 31 Figure 12. Water velocity at Spillimacheen River sampling Stations 2-4, October 22, 2009...... 33 Figure 13. Dissolved oxygen concentration in the Spillimacheen River, Station 3, during the October 22 rampdown...... 34
BC Hydro Page 4 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
SPNMON - 1 STATUS of OBJECTIVES, MANAGEMENT QUESTIONS and HYPOTHESIS
Objective Management Questions Answer to management Management Study conclusion question Hypothesis Provide information to establish 1. How does rampdown 1: Provided that the rampdown Ho: The proposed minimum The null hypothesis (Ho) is that the two hours rampdown duration during outages at the is carried in the prescribed two rampdown duration (two hours) rejected and the alternative protocol (duration and rate) for SPN influence downstream hours, the main stem river stage for planned outages at the (H1) is accepted as the planned generation station river stage during the periods downstream is minimally SPN does not mitigate adverse rates of change of the shutdowns is acceptable to of low river flows? influenced. downstream river stage measured parameters were minimize impacts to fishes changes on fish and fish such that no adverse effect downstream of the habitat. on fishes or fish habitat Spillimacheen Generating could be observed. Station (SPN) 2. Does rampdown 2: No. The main stem margins immediately downstream of the appeared deep enough ( > 30 SPN dewater habitat suitable cm of residual depth) and no for fish spawning or result in signs of egg deposition nor of stranding fishes or deposited suitable spawning ground were eggs? observed in either of the two side channels. No stranded fishes were observed either.
BC Hydro Page 5 Spillimacheen Water Use Plan SPNMON1 Final Report May 10, 2010
Executive Summary
This study examined the effects of a two hours rampdown rate specified for planned outages at the Spillimacheen Generation Station (SPN). The SPN is located on the Spillimacheen River, about five (5) km from the confluence of the river with the Columbia River. Fall and winter river flows are typically less than plant capacity (no spill) and a sudden loss of flow from the SPN can cause an abrupt and significant decrease in stage and discharge in the river channel downstream of the station. This decrease in stage and discharge persists until the headpond surcharges and spills water into a canyon (diversion channel) to offset the reduced plant discharge.
The main objective of the study was to provide information to establish that the two hours rampdown protocol (duration and rate) for planned generation station shutdowns was acceptable to minimize impacts to fishes downstream of the Spillimacheen Generating Station. Target fish species were burbot (Lota lota) and mountain whitefish (Prosopium williamsoni).There was no ramp up specification. The geographic scope of the work was limited to the portion of the Spillimacheen River immediately downstream (within 0.5 km) of the SPN.
The study took place on October 22, 2009, from 9:00 to 14:00 (the rampdown itself was from 10:15 to 12:15), during which time the SPN was shut down over a period of two hours, in increments of 15 minutes. After which time water levels were allowed to stabilize and the SPN units were brought back without a specific rampup rate (all units came back at same rate, at the same time). Data on water quality and fish habitat were collected before, during and after the outage and rampdown at four stations. These stations were placed in areas accessible to crew members while being either representative of the main stem or thought to have relatively high fish stranding risk during rampdowns. There were two stations in the mainstem, two in side channels.
The two hours rampdown rate during the Spillimacheen rampdown (0.0125 m/h) was about half of the prescribed guideline from DFO (0.025 m/h). There were reductions in water levels (4 – 11 %) and discharge (8.5 %), an increase in temperature (0.5 °C), minor reductions in wetted width (less than 1 %) and dissolved oxygen (0.5 %). The changes in water temperature and dissolved oxygen were within the range of daily variations during the rampdown.
The rates of change of the measured parameters were such that no adverse effect on fishes or fish habitat could be observed. The study showed that the two hours rampdown was effective in mitigating the effects of a forced power outage to Spillimacheen River fish habitat. There were no indications of dewatering of redds, eggs or alevins in the wetted channel habitat that became temporarily unavailable for fish use during the rampdown; the risk to early fish stages is thus considered minimal. The main stem margins appeared deep enough (> 30 cm of residual depth) and no signs of egg deposition nor of suitable spawning ground were observed in either of the two side channels. No stranded fishes were observed either. The residual depth of the side channels remained greater than 25 cm during the rampdown period and barriers to access from mountain whitefish or burbot were deemed unlikely.
BC Hydro Page 6 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
The rate and magnitude of changes were however greatest in all measured parameters in the hour following the end of the rampdown period (rampup) although there were no fish stranding observed during the reinstatement of flows.
It is recommended that a rampup rate (rate at which the generating units are restarted into operation after a power outage) of at least 90 min be enforced. No such provision exists at the moment. In the absence of a rampup rate, the entrance to shallow areas with good fish habitat should be blocked with nets prior to rampdown until the end of the rampup period.
BC Hydro Page 7 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Introduction
1.0 Background
A potential negative environmental impact of the operation of any generation station is an abrupt stage change in the river discharge immediately downstream of the dam stemming from plant outages. Abrupt changes in water levels can lead to dewatering of spawning grounds and or fish strandings. The extent and duration of changes in river stage during these events depend on the relative contribution of power intake flows to the total river discharge when the operation is initiated, and how long it takes for the diverted water to reach the downstream area. Rampdown rates, whereby the water discharge is gradually reduced, are generally viewed as an appropriate mitigation measure during planned power outages (Knight Piesold, 2005).
This study examines the effects of a two hours rampdown rate specified for planned outages (cf. below for further details) at the Spillimacheen Generation Station (SPN). The SPN is located on the Spillimacheen River, about five (5) km from the confluence of the river with the Columbia River (Figure 1. ). The Spillimacheen dam is a concrete gravity dam situated 1.5 km upstream of the SPN at the mouth of a steep canyon.
Stage changes are generally attenuated by high channel flows. During freshet, downstream stage changes of the SPN are usually low because headpond inflows are much greater than the 7.5 m3s-1 diversion capacity, which causes continuous spill at the dam. However, fall and winter river flows are typically less than plant capacity (no spill) and a sudden loss of flow from the SPN can cause an abrupt and significant decrease in stage and discharge in the river channel downstream of the station. This decrease in stage and discharge persists until the headpond surcharges and spills water into the canyon to offset the reduced plant discharge to the river downstream of the tailrace.
The primary concerns related to full plant outages at SPN are effects of river stage changes on mountain whitefish (Prosopium williamsoni) spawning (mid October through February), burbot (Lota lota) spawning (January through mid March), and stranding of overwintering fishes downstream of the powerhouse. Abrupt changes in stages can occur from October through April, when the greatest effects on downstream flows occur on occasions of simultaneous outages of all generating units.
Based on a previous assessment of stage/discharge versus timing of outages at the SPN, planned outages can cause up to a 0.4 m drop in river stage downstream of the powerhouse (Gary Birch, Technical Advisor, Environmental and Social Issues, BC Hydro, pers. comm.).
As specified in the System Operating Order for the facility (March 1990), planned and unplanned outages at Spillimacheen are subject to a rampdown duration of at least one hour. To minimize the potential for fish/egg stranding downstream, the Water Use Plan Consultative Committee (CC) agreed that there was a need to assess the effects of a variety of outage sequences on river stage and develop a suitable duration for rampdown operations. The CC recognized that little could
BC Hydro Page 8 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
be done to minimize river stage effects during forced plant outages (e.g., load rejection). However, it recommended that an adaptive approach be taken to determine the rampdown procedure most appropriate to minimize downstream impacts for those occasions when unit shutdown is controlled. The CC recommended that a two hour duration be adopted and an empirical study be undertaken to provide a more defensible rationale for future decisions related to modifying the current rampdown rate at Spillimacheen for planned/unplanned outages during the non-spill period (October-March) and during outages affecting greater than 20 % of total river flows downstream of the powerhouse.
Figure 1. Location of Spillimacheen Generating Station
BC Hydro Page 9 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
1.2 Description of Operations
The following information on the SPN operations is derived from the BC Hydro Operations Manual, Section 3 (BCH Doc. Ref # OM105/02, 1990) and Local Operating Order (Order #3G-SPN-06, 16/5/2008). The Spillimacheen River hydroelectric facility operates as a run-of-river plant with minimal storage capacity. Power production varies with seasonal river flows, with highs in late spring/early summer, and lows in winter. The maximum power flow is 7.5 m3/s, but the generation flows are often lower in the periods between November and March. The Conditional Water Licence (No. 120903) allows for the diversion and use of up to 8.5 m3/s for power generation purposes. Flashboards have been installed on the spillway crest to raise the headpond level in winter and to contain frazil ice through increased volume in the headpond. Spilling at the dam typically occurs from April to October, and the peak spring run-off is in early July. Full supply headpond operating elevation is 865.56 m (58,300 m3), which is level with the top of the flashboards, and the minimum operating level is 863.13 m.
The 14 m high dam diverts water through 1.5 kilometres of penstock to three generating units (one 2.2 MW (G3), and two 0.9 MW-rated (G1, G2) Francis turbines) at the powerhouse (BC Hydro 2000). Under the licence, the minimum flow release from the Spillimacheen Dam in the canyon is 0.85 m3/s when headpond inflows exceed 0.85 m3/s. At inflows less than 0.85 m3/s (e.g., winter flows), the licence requirement is to release available inflows. Other constraints of Spillimacheen generation operations are described in Table 1.
Table 1. Operational constraints for planned outages for Spillimacheen generation flows. Plant Output (assuming all 3 Units to be Shutdown Notify Field Ops Mgr and units are running). Initiate One Hour Rampdown” 4.5 MW + spill > 865.6m G1 or G2 No G3 No Up to 4.5 MW + Spill <865.6 G1 or G2 Yes G3 Yes Up to 4.3 MW G1 or G2 No G3 Yes Up to 2.5 MW (would normally G1 or G2 No have to shut down one unit) G3 No Source: Local Operating Order #3G-SPN-06, 16/5/2008
BC Hydro Page 10 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Two key points of the operating constraints are:
Under the water licence, a two hour rampdown period is required for planned outages resulting in more than a 20 % reduction in power generation;
If all three generating units are running with the plant output at 3 MW, an outage at G1 or G2 will not result in power generation reduction greater than 20 %.
The generation output was 3.2 MW, or approximately 70 % of the production capacity prior to the flow rampdowns during the study period.
1.3 Objective
The main objective of the study was to provide information to establish whether the two hours rampdown protocol (duration and rate) for planned generation station shutdowns was acceptable to minimize impacts to fishes downstream of SPN. There was no ramp up specification. The geographic scope of the work was limited to the portion of the Spillimacheen River immediately downstream (within 0.5 km) of the Spillimacheen Generating Station.
1.4 Management Questions
The main goal of the program was to evaluate the benefits of implementing a two hours ramping rate during full plant outages at the Spillimacheen Generating Station (SPN). The primary management questions were:
1) How does rampdown duration during outages at the SPN influence downstream river stage during the periods of low river flows?
2) Does rampdown immediately downstream of the SPN dewater habitat suitable for fish spawning or result in stranding fishes or deposited eggs?
1.5 Management Hypothesis
The management hypothesis tested by the program related to the effectiveness of the two hours rampdown for protection of fishes:
Ho: The proposed minimum rampdown duration (two hours) for planned outages at the Spillimacheen Generating Station does not mitigate adverse downstream river stage changes on fish and fish habitat.
H1: The proposed minimum rampdown duration (two hours) for planned outages at the SPN mitigates adverse downstream river stage changes on fishes and fish habitat.
BC Hydro Page 11 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
2.0 Methods
2.1 Approach
The study was designed to test the management hypothesis through in situ measurements of changes in Spillimacheen River stage elevation and environmental parameters (dissolved oxygen, temperature, water velocity) during a two hours rampdown period. The expected changes in physical environment were first put into the context of the management hypothesis by completing a literature review of fish habitat changes related to flow ramping.
Data on water quality and fish habitat were then collected before, during and after the outage and rampdown. Data on egg density and fish stranding were also to be collected but their collection proved unwarranted by the lack of dewatering of fish habitat during the rampdown. The rampdown and rampup durations were chosen through consultation with BC Hydro operations managers with the aim of replicating a planned outage at the Spillimacheen Generation Station.
The field study was timed for late October, to coincide with the spawning season of mountain whitefish.
2.2 Literature Review
The literature review focused on mountain whitefish and burbot winter habitat use related to flows and flow ramping in the Spillimacheen River. Grey and primary literature sources were searched, and regional fisheries experts were interviewed (Table 2. ).
Table 2. Sources and search terms used for collection of information during the literature review, Spillimacheen rampdown rate study.
Source Search Terms BIOSIS (includes Biological Flow ramping, fish stranding, Abstracts) winterkill, mountain whitefish, burbot, hydropeaking
River Research and Applications Flow ramping, fish stranding, winterkill, mountain whitefish, burbot, hydropeaking
BC Government Cross-Linked Ramping, burbot, whitefish, Information Resources website Spillimacheen, hydropeaking
Waves Online Catalogue (DFO) Ramping, burbot, whitefish, Spillimacheen, hydropeaking
BC Hydro internal records search Spillimacheen, ramping, hydropeaking
BC Hydro Page 12 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
2.3 Field work
The study focused on fall measurements (late October) rather than winter because winter conditions (late November – late February) were judged too hazardous to collect data. In addition to safety concerns, ice and snow conditions combined with poor channel visibility would have likely affected the quality of the data. Ice formation at the intakes and in the penstocks would have furthermore hindered the logistics of the resumption of operations after a full outage.
Sampling Stations A reconnaissance survey was conducted on October 21, 2009 to establish four sampling stations (Table 3. ). The stations were placed in areas accessible to crew members while being either representative of the main stem or thought to have relatively high fish stranding risk during rampdowns (Figure 2. ). Station 1 was immediately adjacent to the Water Survey of Canada station (WSC Station # 08NA011) on the River Left side main stem approximately 145 m downstream of the generating station. Station 2 was approximately 220 m downstream of the generating station and 40 m downstream of the bridge, on the River Right side of the main stem. Stations 3 and 4, both in shallow channels, were considered to have greater stranding risk than Stations 1 and 2 (located in the main stem). Station 4 was at the confluence of a side channel with the Spillimachee main stem, approximately 250 m downstream of the generating station while Station 3 was located in a narrow side channel parallel to the Spillimacheen River main stem, approximately 360 m downstream of the generating station.
Data collection Data were collected before the outage, during the rampdown and until river stage was back to previous (before outage) conditions. The study took place on October 22, 2009 from 9:00 to 14:00 (the rampdown itself was from 10:15 to 12:15), during which time the Spillimacheen Generation Station was shut down over a period of two hours, in increments of 350 KW every15 minutes. After which time water levels were allowed to stabilize and the SPN units were brought back without a specific rampup rate (all units came back at same rate, at the same time).
Two transects were installed at Stations 3 and 4 to measure changes in water temperature, dissolved oxygen, water level and velocity across two side channels during the ramp down (Figure 2). The Station 3 transect measured 9 m (wetted width), with measurements taken every 15 min during rampdown at in transect widths 2, 5, and 7 m from the left bank. The Station 4 transect measured 9.3 m (wetted width), with measurements taken every 15 min during rampdown at in transect widths 2, 4, 6 and 7.5 m from the left bank. Only water level was measured at Station 1 while water level and velocity were measured at Station 2.
Two teams (two persons each) were stationed at Stations 3 and 4. One person was responsible for Stations 1 and 2. The Station 3 and 4 teams possessed equipment to rescue stranded fishes.
BC Hydro Page 13 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Water Level and Temperature Staff gauges, water level and temperature loggers were installed in the main stem at three of the four station sites (Stations 1-3; Station 4 was outside the main stem). Level loggers (Solinst Model #3001) were installed downstream of the powerhouse to document the local hydraulic response and effective downstream attenuation (Table 3. ). The records from the installed loggers represent changes in pressure from both water depth and the atmosphere. Due to the short duration of the study, the changes to atmospheric pressure were considered to be minor in comparison to the magnitude of changes in water level. A single correction factor for the water level logger readings was determined by placing the leveloggers in a known depth of water (0.5 m) for 24 hours before the study began. During the 24 hour calibration period, the discrepancy between logger reading and the actual water depth was assumed to be related to changing air pressure, and the mean difference in the two readings was used as the correction factor for logger data collected during the ramping study.
Water levels were measured at Stations 3 and 4 with hand held meter sticks at their respective in transect widths every 15 minutes during the rampdown period and for 90 minutes after the end of the rampdown.
The period of record for water temperature available for the study site was limited to less than 24 hours. To gather longer term information, water temperature and water levels fluctuations were obtained from Water Survey Canada for the nearest river site on record (Kootenay River at Fort Steele, WSC gauge ID: 08NG065). The corresponding air temperatures for Kootenay River at Fort Steele were also obtained to compare daily patterns of water and air temperatures. Both water and air temperatures were plotted over the same period as the ramping study.
Spillimacheen River water temperatures were further measured with hand held alcohol thermometers at 15 min intervals at 5 cm depth during the rampdown at Stations 3 and 4.
Water Velocity and Dissolved Oxygen Water velocity was measured at Stations 3 and 4 with a Swoofer current meter placed at 60 % of the total depth at the respective transect location. Measurements were collected every 15 minutes during the rampdown period and for 90 minutes after the end of the rampdown.
Dissolved oxygen was measured at the same stations, widths and intervals than water velocity. Station 3 used a YSI Model 550A while Station 4 used a YSI Model 58.
BC Hydro Page 14 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Figure 2. Approximate location of stations for Spillimacheen monitoring study.
BC Hydro Page 15 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Table 3. Spillimacheen River sampling stations descriptions. Refer to Figure 2 for stations locations. Start and end dates & times apply to level loggers only.
Station 1 Station 2 Station 3 Station 4 Logger Location UTM1 541701; 563934 541778; 563958 541909; 563942 N/A Logger ID SPN-1 SPN-2 SPN-3 N/A Transect Location ID WSC T-1 T-3 T-2 Logger Depth (m) 0.5 0.58 0.28 N/A Start Date/Time 21/10/09; 15:21 MST 21/10/09; 15:30 MST 21/10/09; 16:00 MST N/A End Date/Time 22/10/09; 13:48 MST 22/10/09; 13:56 MST 22/10/09; 13:49 MST N/A Wetted channel width measured (y/n) Y N Y Y Dissolved oxygen measured (y/n) N N Y Y
Transect measurement single single 2, 5, 7 2, 4, 6, 7.5 locations across channel (m) Every minute for Every minute for Every minute for Measurement intervals, temperature and temperature and temperature and N/A level logger water level. water level. water level.
Staff gauge Every 15 minutes for Every 15 minutes for Every 15 minutes for Measurement intervals, measured every 15 velocity and staff D.O., water levels D.O., water levels manual. min. gauge levels. and velocities and velocities
Located on mainstem; at Water Survey of Canada located on mainstem, Hydrometric Station downstream from located on side Notes ID #08NA011 located on mainstem Station 4 channel
1all location coordinates use the 1983 North American Datum reference grid (NAD83), Zone 11
BC Hydro Page 16 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Figure 3. Transects at Stations 3 (left) and 4 (right) in side channels adjacent to the Spillimacheen River, October 22, 2009. Refer to Figure 2 for locations.
2.4 Analyses
The rampdown study was a descriptive study and data were summarized. Microsoft Excel was used for data preparation, summary statistics calculations and figures plotting.
3.0 Results
3.1 Literature Search
Fish Winter Habitat Mountain whitefish use the areas downstream of the SPN dam both as spawning ground and as juvenile rearing habitat. When water temperatures drop below 10°C in fall or early winter, whitefish may begin to spawn, with spawning peaking at temperatures < 6 °C (McPhail 2007). Whitefish spawning takes place over gravel with little or no site preparation. Observations have shown the physical activity of rearing whitefish to be relatively high in comparison to other species (McPhail 2007). Telemetry observations from the Kootenay River in 2008 provided some regional evidence that mountain whitefish spawning took place in that area in November – December (Golder 2009a).
BC Hydro Page 17 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
In October 1991, Triton (1992) sampled six reaches in the Spillimacheen River:
• Reach 1 (0 – 4.8 km; the only reach accessible to anadromous fishes), • Reach 2 (4.8 – 6.0 km; ends at the dam site), • Reach 3 (6.0 – 66.0 km; ends at a 5 m waterfall), • Reach 4 (66.0 - 73.0 km); • Reach 5 (73.0 – 83.0 km); and • Reach 6 (83.0 – 90.0 km).
The Triton (1992) sampling resulted in the capture of mountain whitefish below the dam on October 27-28th, 1991 (Reach 1). These fish ranged from 50 – 195 mm whilst temperatures were 0 - 3°C. The largest whitefish observed in the October 1991 sampling were using the mid-channel habitat and relatively fast waters, perhaps suggesting spawning activity. Another sampling trip on October 20-21, 2002, resulted in observed or captured mountain whitefish at three sites sampled between the SPN and the dam (Bisset and Cope 2003).
Minimum flows for fish habitat requirements (e.g., passage, spawning) are often reported in reference to the size of fishes from the species of interest (Dane 1978; Alaska Dept. of Fish and Game 2001). Mountain whitefish size was positively correlated with depth on a tributary to Finlay Reach (Bustard 1996). While the Bustard (1996) report supports the assumption that larger whitefish need greater amounts of river habitat than smaller individuals, there is no specific information available on minimum spawning depths for whitefish.
Burbot have three basic life history strategies: lacustrine, adfluvial (migrating between lakes and rivers) and riverine (McPhail 2007). Studies in Columbia Lake revealed a population using the adfluvial strategy and spawning in an unnamed tributary at the south end of Columbia Lake (Arndt and Hutchinson 2000b). The unnamed Columbia Lake tributary (Arndt and Hutchinson 2000b) used by spawning burbot is over 60 km upstream of the Columbia River from the mouth of the Spillimacheen River. Although there have not been any studies showing empirical evidence for any of these burbot life history strategies in the Spillimacheen River, it is likely they move to the Columbia River as the capacity for adults of the Spillimacheen River is limited based on its size (S. Arndt, BC Hydro, pers. comm., January 7, 2010). Another option for Spillimacheen burbot could be to rear in the Columbia River, or migrate to Windermere Lake or the Kinbasket Reservoir (M. Neufeld, BC Ministry of Environment, pers. comm., January 11 2010).
Riverine and adfluvial burbot use rivers to spawn in the winter months, in water temperatures ranging from 0 – 5°C (McPhail 2007; Arndt and Hutchinson 2000a). Age of sexual maturity is generally 2 – 4 years (McPhail and Paragamian 2000) and Columbia Lake populations are reported to require four growing seasons (Arndt and Hutchinson 2000). Surveys on October 28, 1991, captured sub-adult burbot ranging from 119 – 167 mm in length in the lowest reach of the Spillimacheen (Reach 1; Triton 1992). These burbot were all caught in the same site, an area with relatively large boulders and shallow water, suggesting that the channel habitat was likely being used for juvenile rearing. Large boulder habitat association for larger burbot juveniles was also reported by Taylor (2001).
BC Hydro Page 18 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Electrofishing, tangle netting and snorkel surveys at three sites below the Spillimacheen dam on October 20-21, 2002, failed to capture or record any burbot, but highly turbid, glacial water conditions may have limited the effectiveness of these efforts (Bisset and Cope 2003). The literature review could not find any report of adult burbot surveys in the Spillimacheen River for January and February.
Water quality is a component of habitat used by whitefish and burbot. O’Neil et al. (2001) compiled key ecological functions associated with several fish species in the Columbia River system. Water velocity associated with mountain whitefish was rated as “slow to moderate” (0 – 1.0 m/s) whilst velocity for burbot was rated as “slow”, but it was not clear if these velocities cover the spawning requirements of either species (O’Neil et al. 2001). Dissolved oxygen (DO) can be a key ecological factor for ice-covered rivers, and minimum DO concentration for whitefish is 3 mg/L, though their eggs are known to develop slowly at this level (NRBS 2002). Burbot eggs are thought to have delayed hatching at levels < 6 mg/L (NRBS 2002).
Effects of Altered Flow & Ramping
Fish Spawning & Passage Mountain whitefish are considered better swimmers than burbot and are generally found in faster flowing water (O’Neil et al. 2001). Preference for depth is listed as both shallow and deep for both species, likely in reference to their respective adfluvial strategies for migrating in and out of rivers (O’Neil et al. 2001). The whitefish spawning period is likely in November and/or December (cf. references above). The late October surveys completed by Triton (1992) reported whitefish adults using the middle channel and faster flowing areas.
Burbot have been studied in relation to altered flows, primarily from the stance of timing of spawning migrations (Arndt & Hutchinson 2000a; Paragamian 1998). Burbot are not strong swimmers and velocities greater than 0.25 m/s were found to be too great for the largest burbot to maintain a stable position (Jones et al. 1974). It is not clear where Spillimacheen burbot are migrating from, but the winter low flows of the Spillimacheen are being assessed in terms of minimum channel depth and velocity rather than maximum flows. Winter river flows, because of their relatively low velocity, may have indirect effects on burbot through migration barriers creation through the formation of shelf and anchor ice.
Cool temperatures (1°C) were found to attract burbot to the Goat River (Paragamian 1998) and they are reported to spawn under ice (Becker 1983). Hence winter flow temperatures alone are not likely to restrict burbot use of the area as much as migration barriers. Burbot upstream spawning movements peaked in late January and early February in an unnamed tributary to Columbia Lake (Arndt and Hutchinson 2000b). In the absence of past burbot surveys in January and February it is not clear where or if burbot spawn in the Spillimacheen River.
BC Hydro Page 19 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Stranding & Flow Ramping
Winter Conditions Fish stranding during flow ramping is a concern during winter low flows on the Spillimacheen. The combination of shelf, anchor and frazil ice reduces the capacity (i.e., fluid volume) of the river to support fishes (Alfredsen and Teskaker 2002; Bradford and Heinonen 2008; Huusko et al., 2007). Flow ramping during shutdowns first dewaters river margins, and these margins can be covered in snow and/or anchor ice during winter flow months in the Spillimacheen River (Anon. 2003).The snow and/or ice cover of the most susceptible areas to stranding means that detecting or mitigating stranded fishes is unlikely. Cooler river temperatures have been shown to increase strandings of juvenile salmon and trout. Saltveit et al. (2001) found stranding rates of Atlantic salmon (Salmo salar) and brown trout (S. trutta) to be greater during winter temperatures (< 4.5 °C) than during higher temperatures because of lower fish activity. Similarly, Bradford (1997) found that more juvenile chinook (Oncorhynchus tshawytscha) were stranded during flow ramping at water temperatures of 6 °C than at 12 °C. Olson and Metzgar (1987) reported that nearly all juvenile Pacific salmonids overwinter in areas of low risk of dewatering.
Attempts have been made to predict winter ice formation in rivers (Moore et al. 2002) but there is little or no evidence that this can be done reliably and with reasonable accuracy. Although models have been used in combination with Light Detection and Ranging (LIDAR) data to quantify effects of flow fluctuations on juvenile salmonids (Prewitt and White 1986; Whited et al. 2002), this type of tool should be paired with some empirical data verification to ensure that it is effective for the target species, life stage and reach. Verification of modelled winter flows in the Spillimacheen River may need to be done opportunistically at locations that are accessible and show fish stranding unambiguously.
Day vs. Night The literature review could not find any study on ramping tests on mountain whitefish or burbot stranding nor was this information available from other ramping reviews (Hunter 1992; Golder 2009b). Day vs. night stranding risk appears inconsistent across all species and generalizations should not be made without empirical testing for the species of interest. Diurnal variations in stranding rates have been observed during flow ramping tests whereby juvenile salmonids were stranded less at night than in daytime periods. (Beck & Associates 1989; Halleraker et al. 2003). Steelhead fry (O. mykiss) were more frequently stranded during night rampdowns than during the day, but chinook fry (O. tshawytscha) showed the opposite trend in the Sultan River in Washington (Olson and Metzgar 1987).
BC Hydro Page 20 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
3.2 Stage monitoring
3.2.1 Water discharge
Water Survey of Canada (WSC) records water levels every 15 minutes at its gauge on the Spillimacheen River (Station 1, Figure 2). The stage-discharge relationship developed by Environment Canada for the Spillimacheen station was used to convert the water level recordings to discharge estimates during the rampdown study. Discharge estimates based on the WSC gauge showed a 29 cms (27 %) reduction during the week of the rampdown (October 19-25, 2009) (Figure 5) The resulting flow change rate was 0.17 m3/s, and 0.0025 m/h for water level during the week of the rampdown.
During the two hour rampdown period, the WSC’s logger recorded a 0.025 m (4.6 %, 0.0125 m/h) reduction in water level, corresponding to an estimated 1.24 cms (8.5 %, 0.62 m3/s) reduction in discharge (Figure 5).
There was a greater than three fold difference (0.62 vs. 0.17 m3/s) in discharge flux, and a five fold (0.0125 vs. 0.0025 m/h) difference in water level rate of change during the rampdown (October 22) than during the seven days period surrounding the rampdown (October 19-25).
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Spillimacheen Hourly Discharge
45
40
35
30
25
20
15 Discharge (cms)
10
5
0 0 20 40 60 80 100 120 140 160 180 Elapsed Time (h)
Figure 4. Water discharge data from the Spillimacheen River, October 19 to October 25, 2009. Data from WSC station # 08NA011. Red circle encloses the approximate duration of the rampdown study.
Spillimacheen River at WSC Gauge
25 0.7 Discharge Water Level 0.6 20 0.5
15 0.4
0.3 10 Water Level (m) Level Water Discharge (cms) Discharge Begin rampdown End rampdown 0.2 5 0.1
0 0.0 0:00 2:38 5:16 7:55 10:33 13:12 15:50 18:28 21:07 23:45 Time of Day (hh:mm)
Figure 5. Water Survey Canada data for the Spillimacheen River (Station 1, Figure 2) on October 22, 2009.
BC Hydro Page 22 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
3.2.2 Effect of rampdown on water levels
The stage results from the three level loggers showed a consistent pattern across all locations during and outside the two hour rampdown period (
Station 1
75 4.2 Water Level Temperature Start rampdown 4.1
70 4.0 End rampdown 3.9
65 3.8
3.7 60 Water Level (cm) Temperature (°C) Temperature
3.6
3.5 55
3.4
50 3.3
9 3 00 24 3 12 0 36 00 24 0: 1:30 2:21 3: 4: 4:54 5:45 6: 7:27 8:18 9:09 16:09 17: 17:51 18:42 19:33 20: 21:15 22:06 22:57 23:48 10: 10:51 11:42 12:33 13: Time (hh:mm)
Station 2
75 4.2 Water Level Temperature Start rampdown 4.1
70 4.0 End rampdown 3.9
65 3.8
3.7 60 Water Level (cm) Temperature (°C) Temperature 3.6
3.5 55
3.4
50 3.3
9 00 33 06 3 12 45 18 51 24 0: 1:30 2:21 3: 4:03 4:54 5: 6:36 7:27 8: 9:09 16:09 17: 17:51 18:42 19: 20:24 21:15 22: 22:57 23:48 10:00 10: 11:42 12:33 13: Time (hh:mm)
BC Hydro Page 23 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Station 3
43 4.2 Water Level Start rampdown Temperature 41 4.1
End rampdown 39 4.0
37 3.9
35 3.8
33 3.7 Water Level(cm) Temperature (°C) Temperature 31 3.6
29 3.5
27 3.4
25 3.3
51 24 06 57 39 12 :00 51 :33 0: 1:30 2:21 3: 4:03 4:54 5:45 6:36 7:27 8:18 9:09 0 2 16:09 17:00 17: 18:42 19:33 20: 21:15 22: 22: 23:48 1 10: 11:42 1 13:24 Time (hh:mm)
Figure 6). Prior to the rampdown, water levels at stations 1, 2, and 3 had declined 5, 4 and 11 %, respectively in the initial four hours of monitoring after their installation (16:09 MST) on October 21st. Following that pre-rampdown water level decline, all logger stations recorded increases (9, 6, 18 % for 1, 2, and 3, respectively) until the beginning of the rampdown at 10:15 MST on October 22nd. Water levels measured manually at Station 4 were not recorded during the pre-rampdown period.
The declines in water levels over the two hour rampdown period at Stations 1, 2 and 3 were 2.2, 2.0, and 1.4 cm, respectively (difference from start to end of rampdown;
Station 1
75 4.2 Water Level Temperature Start rampdown 4.1
70 4.0 End rampdown 3.9
65 3.8
3.7 60 Water Level (cm) Temperature (°C) Temperature
3.6
3.5 55
3.4
50 3.3
9 3 00 24 3 12 0 36 00 24 0: 1:30 2:21 3: 4: 4:54 5:45 6: 7:27 8:18 9:09 16:09 17: 17:51 18:42 19:33 20: 21:15 22:06 22:57 23:48 10: 10:51 11:42 12:33 13: Time (hh:mm)
BC Hydro Page 24 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Station 2
75 4.2 Water Level Temperature Start rampdown 4.1
70 4.0 End rampdown 3.9
65 3.8
3.7 60 Water Level (cm) Temperature (°C) Temperature 3.6
3.5 55
3.4
50 3.3
9 :09 :00 :51 :42 :33 :24 :15 :06 :57 :48 3 12 45 18 :00 :51 :42 :33 :24 0: 1:30 2:21 3: 4:03 4:54 5: 6:36 7:27 8: 9:09 16 17 17 18 19 20 21 22 22 23 10 10 11 12 13 Time (hh:mm)
Station 3
43 4.2 Water Level Start rampdown Temperature 41 4.1
End rampdown 39 4.0
37 3.9
35 3.8
33 3.7 Water Level(cm) Temperature (°C) Temperature 31 3.6
29 3.5
27 3.4
25 3.3
51 24 06 57 39 12 :00 51 :33 0: 1:30 2:21 3: 4:03 4:54 5:45 6:36 7:27 8:18 9:09 0 2 16:09 17:00 17: 18:42 19:33 20: 21:15 22: 22: 23:48 1 10: 11:42 1 13:24 Time (hh:mm)
Figure 6), followed by peak increases of 10.2, 8.3 and 5.3 cm following the return of operations (rampup). The water levels measured at the two side channel transects followed similar patterns, declining 3 and 1 cm during the rampdowns (median values), followed by median increases of 6 and 4 cm during the rampup period (Figure 7.). In all cases, the levels had stabilized to pre-rampdown conditions within two hours of outage completion (average duration of approximately 60 min).
The changes in levels during the rampdown at Station 1 were comparable with those measured by the level logger operated by Environment Canada (change of 4.8 % at Station 1 logger vs. change of 4.6 % for Environment Canada WSC station).
3.2.3 Effect of rampdown on water temperature
The temperature sensors in the level loggers showed an increase of less than 0.5 °C in Spillimacheen water temperature at all sites during the rampdown period. Once the rampdown period ended, the water temperature continued to rise in the following hour. The Spillimacheen River temperature continued to rise
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after the end of the rampdown occurred while discharge increased and then declined before stabilizing to pre-rampdown levels. The disconnection between water level and temperature trends is further described in the Kootenay River site below.
Station 1
75 4.2 Water Level Temperature Start rampdown 4.1
70 4.0 End rampdown 3.9
65 3.8
3.7 60 Water Level (cm) Temperature (°C) Temperature
3.6
3.5 55
3.4
50 3.3
9 3 00 24 3 12 0 36 00 24 0: 1:30 2:21 3: 4: 4:54 5:45 6: 7:27 8:18 9:09 16:09 17: 17:51 18:42 19:33 20: 21:15 22:06 22:57 23:48 10: 10:51 11:42 12:33 13: Time (hh:mm)
Station 2
75 4.2 Water Level Temperature Start rampdown 4.1
70 4.0 End rampdown 3.9
65 3.8
3.7 60 Water Level (cm) Temperature (°C) Temperature 3.6
3.5 55
3.4
50 3.3
9 00 33 06 3 12 45 18 51 24 0: 1:30 2:21 3: 4:03 4:54 5: 6:36 7:27 8: 9:09 16:09 17: 17:51 18:42 19: 20:24 21:15 22: 22:57 23:48 10:00 10: 11:42 12:33 13: Time (hh:mm)
BC Hydro Page 26 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Station 3
43 4.2 Water Level Start rampdown Temperature 41 4.1
End rampdown 39 4.0
37 3.9
35 3.8
33 3.7 Water Level(cm) Temperature (°C) Temperature 31 3.6
29 3.5
27 3.4
25 3.3
51 24 06 57 39 12 :00 51 :33 0: 1:30 2:21 3: 4:03 4:54 5:45 6:36 7:27 8:18 9:09 0 2 16:09 17:00 17: 18:42 19:33 20: 21:15 22: 22: 23:48 1 10: 11:42 1 13:24 Time (hh:mm)
Figure 6. Spillimacheen water levels and temperatures recorded by level loggers at Stations 1-3, October 21-22, 2009. Bars and shaded areas indicate duration of rampdown. Refer to Figure 2 for locations of stations.
0.40
0.35
0.30 ) 0.25 7.5 6 0.20 4 2 0.15 Staff gaugeStaff level (m
0.10
0.05
0.00 0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225
Elapsed time (min)
BC Hydro Page 27 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
0.30
0.25
0.20 )
7 0.15 5 2
Staff gaugeStaff level (m 0.10
0.05
0.00 0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225
Elapsed time (min)
Figure 7. Staff gauge water levels of Spillimacheen side channels (lines are substations, m from left bank), Stations 4 and 3, measured on October 22, 2009. Dashed lines enclose rampdown duration.
Daily trends in river water temperature were not available for the Spillimacheen River, but trends may be inferred based on data collected from the Kootenay River at Fort Steele. In the hour leading up to, and 6-12 hours after, 12:00 MST, the water temperature in the Kootenay River showed a daily increase in the afternoons of October 21 and 22, 2009. This daily warming trend in Kootenay River temperature was present in the days preceding and following the study period (October 19-25, Figure 8). Although there was a continuous 9 % decrease in water level in the Kootenay River, the water temperature did not track this reduction during the October 21 – 23 period (Figure 8). Water temperature oscillated from 6.1 to nearly 7°C during that same period (Figure 8).
Air temperature data from the Kootenay River were used in the absence of available data for the Spillimacheen study site. There were daily oscillations in air temperature by the Kootenay River (Figure 9).
Overall, Kootenay River water and air temperature followed similar patterns (Figure 10) while being unrelated to variations in water levels during the same period as the Spillimacheen study.
BC Hydro Page 28 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Figure 8. Water temperature and level for the Kootenay River at Fort Steele WSC gauge, October 19-25.
Figure 9. Water and air temperature for the Kootenay River at Fort Steele WSC gauge, October 19-25.
BC Hydro Page 29 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Figure 10. Air and water temperature for the Kootenay River at Fort Steele WSC gauge, October 21-23, 2009. Note that axes are different from Figure 8.
3.2.4 Effect of rampdown on wetted widths
There were total reductions in wetted width of 4 and 7 cm during the two hour rampdown period at the side channels in Stations 3 and 4, respectively. These reductions in wetted width represented less than a 1 % change in the channels widths, and took place within 30 minutes of the initiation of the rampdown (Figure 11). The two channels widths stabilized until the end of the two hours rampdown (Figure 11). The most dramatic changes in wetted widths came after the two hours rampdown had been completed, during resumption of the operations (rampup) (Figure 11). In two hours following the rampdown, Station 3 and 4 wetted widths increased 4 and 2 cm (1 and 2 % increases in pre-rampdown widths) respectively, before returning to pre-rampdown levels.
Observers collecting data at each station did not observe any fish stranding during the changes in wetted areas.
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Station 3 (T-3) 9.60 9.58 9.56 9.54 9.52 Start of rampdown 9.50 End of rampdown 9.48 9.46 Wetted Width (m) Width Wetted 9.44 9.42 9.40 0:00 0:30 1:00 1:30 2:00 2:30 3:00 3:30 4:00 4:30 Elapsed Time (h:mm)
Station 4 (T-2)
9.50
9.45 Start of rampdown 9.40
9.35 End of rampdown 9.30
9.25 Wetted Width (m)
9.20
9.15 0:00 0:30 1:00 1:30 2:00 2:30 3:00 3:30 4:00 Elapsed Time (h:mm)
Figure 11. Wetted widths for Spillimacheen sampling transects, October 22, 2009.
3.2.5 Effect of rampdown on water velocities
Water velocities were measured across each transect at Stations 3 and 4, whereas velocity was measured from a single location at Station 2. Prior to commencing the rampdown, the velocities were 0.13, 0.06, and 0.17 m/s (the latter two being median values) for Stations 2, 3, and 4, respectively. Velocities increased slightly at Stations 2 and 3 once rampdown began, while Station 4
BC Hydro Page 31 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
velocity decreased. The changes in median water velocities over the two hours rampdown period were a 0.03 m/s increase for Station 2, a 0.06 m/s increase at Station 3 and a 0.03 m/s decrease at Station 4.
There were 69, 33 and 138 % increases in maximum velocity in the following 45- 60 minutes after rampup started at Station 2, 3 and 4, respectively (Figure 12). The largest absolute increase in median velocity was 0.23 m/s at Station 4. Velocities had returned to levels comparable to the pre-rampdown conditions at each station after 60 minutes after the end of rampdown.
BC Hydro Page 32 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Station 2 (T-1) 0.45 0.40 End of ramp-down 0.35 0.30 Start of ramp-down 0.25 0.20 0.15 Velocity (m/s) Velocity 0.10 0.05 0.00 0:00 0:30 1:00 1:30 2:00 2:30 3:00 3:30 4:00 Elapsed Time (h:mm)
Station 3 (T-3) 0.45 0.40 0.35 Start of ramp-down End of ramp-down 0.30 0.25 0.20 0.15 0.10 0.05 Median Water Velocity (m/s) 0.00 0:00 0:30 1:00 1:30 2:00 2:30 3:00 3:30 4:00 Elapsed Time (h:mm)
Station 4 (T-2) 0.45 0.40 Start of ramp-down 0.35 0.30 End of ramp-down 0.25 0.20 0.15 0.10 0.05 Median Water Velocity (m/s) 0.00 0:00 0:30 1:00 1:30 2:00 2:30 3:00 3:30 4:00 Elapsed Time (h:mm)
Figure 12. Water velocity at Spillimacheen River sampling Stations 2-4, October 22, 2009.
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3.2.6 Effect of rampdown on Dissolved Oxygen
Rampdown and rampup had minimal effects on dissolved oxygen concentrations. Changes in dissolved oxygen concentrations were negligible or below the detection limits at Station 4 during the rampdown. There was a reduction of 0.04 mg/L (less than 0.5 %) of dissolved oxygen in the channel section at Station 3 and a 0.34 mg/L (3 %) increase during the rampup period before stabilizing to pre-rampdown levels (Figure 13)
Station 3 (T-3)
14
12
10
8 Start of rampdown 6 End of rampdown 4
Dissolved Oxygen (mg/l) Oxygen Dissolved 2
0 0:00 0:30 1:00 1:30 2:00 2:31 3:01 3:31 4:01 4:32 Elapsed Time (h:mm)
Figure 13. Dissolved oxygen concentration in the Spillimacheen River, Station 3, during the October 22 rampdown.
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4.0 Discussion
The flow rampdown at the Spillimacheen Generation station provided an opportunity to measure changes in various physical parameters immediately downstream of the generating station. During the two hours rampdown, there were reductions in water levels (4 – 11 %) and discharge (8.5 %), an increase in temperature (0.5 °C), minor reductions in wetted width (less than 1 %) and dissolved oxygen (0.5 %). Water velocity changes ranged from an increase of 12 % to a decrease of 17 %.
The rate and magnitude of changes were greatest in all measured parameters in the two hours following the end of the rampdown period (rampup). No fish stranding were observed during the two hour shutdown or reinstatement of flows.
Water level The main stem river water stage was reduced by 3.9 – 4.5 % during the two hours rampdown period. The rate of main stem stage change during the two hour rampdown (0.0125 m/h) was five fold greater than that observed in the week of October 19-24 (0.0025 m/h). However, the maximum ramping rate guideline from DFO is 0.025 m/h (Knight Piesold 2005), and the rampdown rate during the Spillimacheen rampdown was thus about half of the prescribed guideline.
The water level ‘pulsed’ following resumption of operations, increasing at a maximum rate of 0.15 to 0.28 m/h during a 20 min period before decreasing to pre-rampdown levels. Although this was for a relatively short time and the absolute change in water levels during that period was less than 10 cm, this is more than ten times the rampdown rate prescribed by DFO.
The downside segment of the pulse translated in equivalent rampdown rates ranging from 16-17 cm/h (Station 1, closest to the SPN) to 8 cm/h (Station 3, furthest from SPN), once again higher than the guideline recommendation by DFO.
The side channel site (Station 4) showed a greater relative reduction in stage height (15 % drop from original level in one case) than the main stem during the two hours rampdown. As with the main stem sites, the rampup period produced the greatest changes in stage height (8 cm, 22 % above the original level).
Temperature The increase in water temperature coincided with both reduced flows and increases in daily solar radiation. As the temperatures moved toward the daily high, the air around the site likely warmed and influenced the channel water. The morning period, when the rampdown took place, would have experienced the daily warming period, although no air temperature data were available to confirm this trend. The Kootenay River water level, air and water temperature records for the same period showed that air and water temperatures increased at similar rates and times, but were not synchronized with water levels changes. The same would appear to be the case for the Spillimacheen River water temperatures in the short period before or after the rampdown as they increased after water levels decreased.
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It is probable that air temperature has a greater influence on water temperatures than water level in the Spillimacheen River during the fall warmest period of the day. This should however not be extrapolated to winter conditions when the influence of air temperature on water temperature may be affected by the presence and thickness of ice. In the absence of a controlled study during a period of stable air temperature, it is not possible to determine the relative or absolute influence of ramping rate and water level changes on the river temperature during winter conditions.
The data on Spillimacheen river temperature in post-rampdown conditions, as well as the trends from the Kootenay River, point to air temperature having a stronger influence than water level. Regardless of the cause of the temperature change, the magnitude of change was roughly 0.5 °C, and the literature reviewed on temperature effects on fishes does not show this amount of change, over two hours, to have measureable effects on fishes.
Wetted Width The rampdown reduced side channels widths by 4 to 7 cm. The marginal areas which were dewatered did not harbour fish strandings, but there was the potential to dewater eggs and alevins located in the river margins. Without knowing the distribution of eggs in the Spillimacheen channel, is not possible to quantify the potential number of eggs dewatered. Overall 0.5 to 0.8 % of the wetted channel habitat became temporarily unavailable for fish use during the rampdown, and an unknown number of eggs may have been dewatered during this period. Visual assessments of the dewatered areas did not reveal any indications of redds, eggs or alevins, and the risk to early fish stages is considered minimal.
The flow increase which took place after the two hours rampdown lead to a 1.25 % (12 cm) increase in wetted area in the side channels before widths stabilized to their pre-rampdown levels. This sudden increase in wetted width followed by a sudden decrease in water levels could lead to stranding of alevins and washing up of pelagic eggs in suboptimal habitats.
Water velocity Velocity changes may cause juvenile fishes to be displaced or disrupt spawning initiated in response to flow conditions. The focus of this study was to examine potential effects of a prescribed rampdown rate on fish stranding or egg dewatering. The changes in water velocities during rampdown were relative increases ranging from 23 % (Station 2) to < 1 % (Station 3). The only site showing a drop in velocity was the side channel at Station 4, a relative decrease of 15 %.
The water velocity however increased suddenly once the generating units resumed operations simultaneously (relative increases ranging from 33 to 138 %). While the absolute velocities increases ranged from 0.03 m/s to 0.23 m/s, sudden and unpredictable increases in water velocity could easily displace alevins or other juvenile fishes from favoured habitats (e.g., Salveit et al 2001).
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Dissolved Oxygen The change in dissolved oxygen (DO) was less than 0.5 mg/L. The pre- and post-rampdown DO levels were all greater than 12 mg/L. Given that adverse effects in the target species have not been documented until levels go below 6 mg/L (NRBS 2002), there are no DO - related effects anticipated as a result of the Spillimacheen rampdown over two hours.
Management Questions
1. How does rampdown duration during outages at the SPN influence downstream river stage during the periods of low river flows?
2. Does rampdown immediately downstream of the SPN dewater habitat suitable for fish spawning or result in stranding fishes or deposited eggs?
1. Provided that the rampdown is carried in the prescribed two hours, the main stem river stage downstream should be minimally influenced: the maximum observed absolute decrease in water level was 2.9 cm at Station 1 (level logger). Side channels showed slightly greater drops in water levels than the main stem sites (maximum decrease of 4 cm, or 15 % of depth at Station 4).
2. No. The main stem margins appeared deep enough (> 30 cm of residual depth) and no signs of egg deposition nor of suitable spawning ground were observed in either of the two side channels. No stranded fishes were observed either. The residual depth of the side channels remained greater than 25 cm during the rampdown period (although the depth at one of Station 4 margins dropped from 13 to 11 cm), and barriers to access from mountain whitefish or burbot are unlikely.
BC Hydro Page 37 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Management Hypothesis:
Ho: The proposed minimum rampdown duration (two hours) for planned outages at the Spillimacheen Generating Station does not mitigate adverse downstream river stage changes on fish and fish habitat.
H1: The proposed minimum rampdown duration (two hours) for planned outages at the SPN mitigates adverse downstream river stage changes on fish and fish habitat.
The null hypothesis (Ho) is rejected and the alternative (H1) is accepted as the rates of change of the measured parameters were such that no adverse effect on fishes or fish habitat could be observed. The study showed that the two hours rampdown was effective in mitigating the effects of a forced power outage to Spillimacheen River fish habitat. The habitat requirements of the target species are such that the changes in habitat observed over the two hours rampdown period are unlikely to cause any direct, adverse effect to the target fish habitats.
The result of this study moreover shows that the changes in water temperature and dissolved oxygen during a two hour rampdown are within the range of daily variations seen in the Spillimacheen River and that the rampdown rate prescribed by the Consultative Committee for SPN is well below the DFO guideline. Testing of rampdown rates of four and six hours is therefore not required.
BC Hydro Page 38 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
5.0 Recommendations
o A rampup rate (rate at which the generating units are restarted into operation after a power outage) of at least 90 min should be implemented. No such provision exists at the moment. The study showed a surge in water levels and velocities immediately downstream of SPN as the generating units restarted and the water came through the penstocks. This surge, however brief (average duration was 60 min until water levels receded to pre-rampdown levels), may either lead some fishes to strand in shallow areas or displace spawning adults or juvenile fishes.
o The effects of the proposed 90 min rampup rate (hydropeaking) on fish habitat and habitat use in the Spillimacheen should be tested. The procedure should be similar to the one described in this report.
o In the absence of a rampup rate, the entrance to shallow areas with good fish habitat should be blocked with nets prior to rampdown until the end of the rampup period. This would prevent access from main stem fishes to such areas and minimize their risk of stranding. Juvenile fishes are especially prone to the effects of surging water.
o Consideration of mountain whitefish and burbot spawning in the Spillimacheen River means that minimum flows for fishes should be enforced from October through February. The flow volumes needed during the spawning period could be estimated once specific spawning areas are identified. In the absence of data for November-February, resource planners can apply a conservative approach which allows for sufficient flow releases needed to preserve depths for adult passage throughout the five (5) km from SPN to the confluence of the Spillimacheen with the Columbia River.
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Literature Cited
Alaska Department of Fish and Game and Alaska Department of Transportation. 2001. Memorandum of Agreement Between Alaska Department of Fish and Game and Alaska Department of Transportation and Public Facilities for the Design, Permitting, and Construction of Culverts for Fish Passage. Juneau Alaska, Alaska Department of Fish and Game, Alaska Department of Transportation. 33pp.
Alfredsen, K., and E. Tesaker. 2002. Winter habitat assessment strategies and incorporation of winter habitat in Norwegian habitat assessment tools. Hydrological Processes 16: 927-936.
Anon., 2003. Spillimacheen water use plan, consultative committee report. Prepared for BC Hydro, Burnaby, BC.
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BC Hydro Page 42 Spillimacheen Water Use Plan SPNMON-1 Final Report May 10, 2010
Acknowledgements
The authors would like to thank Rian Hill of BC Hydro, and Chris Joseph and Neil Roundheim from the Canadian Columbia River Intertribal Fisheries Commission for assistance with the field study and data collection. Rian Hill was the Watershed Study Lead and Jeff Berdusco the Study Lead. Lee Perkull, electrician, BC Hydro, supervised the outage and his and willingness to communicate and implement our requests were essential to implementing the field work. Kevin Dunk (Environment Canada – Water Survey of Canada Section) provided WSC gauge data and discharge estimates for the October 19-25, 2009, period. Steve Arndt (BC Hydro), and Matt Neufeld (BC Ministry of Environment, Nelson Office) provided regional information on burbot. Dean den Biesen (BC Hydro, Castlegar) provided invaluable technical information on the Spillimacheen Generating Station and on the history of the project.
BC Hydro Page 43 Appendix I
Habitat Photographs
SPNMON -1 Appendix I 1
Photo 1. Spillimacheen Generating Station (SGS) Photo 2. The three generating units of the Spillimacheen viewed from the bridge, Oct 22, 2009. Generating Station.
Photo 3. Spllimacheen River downstream of SGS, October 21, 2009. This area was reported to potentially harbour mountain whitefish spawning.
SPNMON -1 Appendix I 2
Photo 4. SGS at start of rampdown, 10:15, Oct 22, Photo 5. SGS half way through rampdown, 11:15, Oct 2009. 22, 2009.
Photo 6. SGS at end of rampdown, 12:15, Oct 22, Photo 7. SGS during rampup, 13:15, Oct 22, 2009. 2009.
SPNMON -1 Appendix I 3
Photo 8. SGS tailrace before rampdown, 9:15, Oct Photo 9. SGS tailrace half way through rampdown, 22, 2009. All three generating units are functioning. 11:15, Oct 22, 2009. Notice that water is still trickling.
Photo 10. SGS tailrace at end of rampdown, 12:20, Photo 11. SGS tailrace at start of rampup, 12:45, Oct Oct 22, 2009. 22, 2009.
SPNMON -1 Appendix I 4
Photo 12. Station 1 at start of rampdown, Photo 13. Station 1 at end of rampdown, 10:30, Oct 22, 2009. 12:25, Oct 22, 2009.
Photo 14. Station 1 during rampup, 13:05, Oct Photo 15. Measuring water velocity, Station 3. 22, 2009. Notice that the water level is slightly higher than at the start of the rampdown.
SPNMON -1 Appendix I 5 Photo 16. Station 4 at start of rampdown, 10:15, Oct Photo 17. Station 4 half way through rampdown, 11:35, 22, 2009. Oct 22, 2009. Notice that margins are almost dewatered.
Photo 18. Station 4 at end of rampdown, 12:10, Oct Photo 19. Station 4 during rampup, 13:05, Oct 22, 22, 2009. 2009.
SPNMON -1 Appendix I 6
Photo 20. Spillimacheen River, looking downstream from the bridge, October 22, 2009. Arrow points to the entrance to the side channel (Station 4 ).
SPNMON -1 Appendix I 7
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