Puntledge River Hydroelectric System: Overview

Transcription

1 Puntledge River Hydroelectric System: Overview City of Courtenay Mayor and Council November 16,

2 Agenda Agenda Puntledge River hydroelectric operations: The system; and Drought to flood risk management operations; Puntledge River Water Gauges and Siren System Upgrade Project; and Questions 2

3 Puntledge River System 3

4 Puntledge River System 4

5 Puntledge River System Fish flow requirements: Gauge 6 (below diversion dam) flow is 5.7 m3/s; and Gauge 8 (below generating station) flow is 15.6 m3/s. Operational considerations: 17 two-day fish pulse flows over the year; One two-day kayak flow each May; Water supply to hatchery; and CVRD raw water extractions for domestic consumption. 5

6 Puntledge River System Non-requirements or voluntary considerations: April-July DFO Summer Chinook strategy: Release below 65 m3/s at Gauge 8 where possible. October-November Sports fishery for chum salmon: Gauge 8 river flows of 45 m3/s and lower for good river access; if a requirement to spill for flood risk management, do so Monday-Friday. November-March During required spill events for flood risk management, consider ideal kayak flow conditions of 110 m3/s. 6

7 Puntledge River System Typical fall/winter/spring operations: Release minimum of about m3/s from Comox Dam: 5.7 m3/s down 5 km stretch for fish habitat flows; 27 m3/s down pipeline to the 24 megawatt generating station; and Releases above 200 m3/s for flood risk management. Typical summer (July-September) operations: Release about 16 m3/s from Comox dam; Run generating station at about 1/3 capacity; Gauge 8 went as low as 7.5 m3/s during extreme spring/summer drought of 2015; and Water License variances are common. 7

8 Puntledge River System Variation In Weather & Water Abundance Water Supply 2013/2014: Driest Year On Record Water Supply 2014/2015: One Extreme To Another 8

9 Puntledge River System Perceptions Kayaking event in May: why release so much? Coincides with overabundance of water and a full reservoir; Rainforest climate: Most water falls from November to January. Snowmelt provides flow through July. Lowest inflow period coincides with driest period of August-September; Winter hourly peak inflows into the reservoir as high as 900 m3/s; Summer inflows into the reservoir as low as 1 m3/s; and Reservoir managed (balanced) across water use interests: power generation, security of CVRD water supply, maintenance of downstream fishery flows, recreation flows, and flood control. 9

10 Puntledge River System Drought Conditions 1

11 Puntledge River System Flood Risk Management BC Hydro can attenuate high inflows and control water releases downstream to limit potential flooding. With multiple storms this flexibility diminishes over time as reservoir storage is filled. BC Hydro s dam is unable to eliminate the possibility of flooding, but it can reduce the size, frequency and impact of such events. Flooding has taken place a few times since November 2009 and December Periodically, BC Hydro participates in table top exercises with local government and community emergence response leaders. The Comox dam is seismically safe. It is a concrete dam founded on bedrock. Dam Safety Program. 1

12 Puntledge River System Flood Risk Management Olympic-sized swimming pool entering the reservoir every 3.5 seconds. Storm examples: January and December

13 Puntledge River System Flood Risk Management January 2010 storm example 13

14 Puntledge River System Flood Risk Management 14

15 2015/2016 Water Supply Year? Forecast is warmer and drier than normal: The Blob in place since 2012/2013; and El Nino this year looks similar to May be a wetter January. Flood risk management operations ready for the November to January period: Timing of ocean tides, storm surge, and the Browns and Tsolum river peak flows. (King Tides near end of November and near end of December.) 15

16 Capital Projects Over the next 10 years, BC Hydro will invest an average of $2.4 billion a year on the electricity system including upgrades to transmission and distribution systems and dams and generating stations. John Hart Generating Station Replacement Project 1

17 Water Level Gauges & Public Warning System BC Hydro s top priority is public safety and we take the potential safety risks on the Puntledge River system very seriously. To continually improve worker and public safety; BC Hydro has been regularly communicating on its operations to the Comox Valley community; BC Hydro s Comox and Puntledge River diversion dams are functioning normally and are safe, and supported by a comprehensive dam safety program; and We have a long term plan to improve the sustainability, performance and safety of our hydroelectric facilities. 17

18 Water Level Gauges & Public Warning System This project will improve public safety and provide more reliable watershed flow information. Siren warning system (6 sirens) upgrades; and Water gauges (8 gauges) on the Puntledge, Browns and Tsolum rivers will be upgraded. The total estimated project cost for the Puntledge Water Level Gauges and Public Warning System is about $8 million. System improvements to begin this spring and be in operation by November

19 Water Level Gauges & Public Warning System Benefits: Sirens: The existing sirens will be replaced with modern sirens and control systems that will direct the sound towards where it is needed on the river while reducing the sound volume to areas outside the river. There will also be strobe lights, most commonly used at night. This means better river use safety. Gauges: Upgrades will provide more accurate, reliable and closer to real-time watershed water flow conditions. This will enhance BC Hydro s operations to more efficiently manage flows from Comox dam for fish habitat during extreme droughts, to flood risk management during storms. Watershed flows and levels on BC Hydro web site: 19

20 Puntledge River - Warning System Puntledge Park (1) Powerhouse (1) Stotan Falls (2) Nymph Falls (2) Puntledge Diversion Dam (Barber s Hole) (2) Comox Dam (2) 20

21 Puntledge River - Warning System BC Hydro Public Safety carries out a review of the river system every three years. Modifications have been done over the years, though this is the most comprehensive system update in decades. Future reviews may modify and add siren locations as the public use along the river evolves. We hired an Audibility Engineering Consultant to undertake a audibility study to determine the location of each siren site at each area. We are wanting the sirens to be more in the river where the risks are, versus further away from the river as they are now nuisance considerations.. 21

22 Puntledge River - Water Gauges Not shown: Gauge 10 at 5th Street Bridge; and Gauge 11 at Goose Spit Tidal 22

23 Communications With Water Gauges & Warning System 23

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25 Puntledge River Communication Poles Low Energy with 0.5 watt radios (analogy: a two-way walkie-talkie is a 2-4 watt radio (4-8 times higher)); Far Away Mounted at a minimum of 7 metres from ground level on poles; Safe Our technician can safely handle the equipment when operating; The station is fully compliant with Health Canada Safety Code 6; Average level measured is 0.7% of 2015 limit at 0.2 m distance; and Level measured for a 6 person standing at the base of the pole is 0.02%. Radio wave energy falls rapidly with distance. At ground level it would be negligible. Private property approvals: initial discussions have taken place with landowners. 25