Puntledge River Hydroelectric System: Overviewforbiddenplateauroadassociation.com/images/Courtenay...5 Puntledge River System Fish flow requirements: Gauge 6 (below diversion dam)

Puntledge River

Hydroelectric System:

Overview

City of Courtenay

Mayor and Council

November 16, 2015

1

Agenda

2

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

3

Puntledge River System

4


5


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.

6


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.

7


Typical fall/winter/spring operations:

Release minimum of about 32-33 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.

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

9


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.

1

0


Drought Conditions

1

1

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

2014.

• 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.

12


Risk Management

Storm

examples:

January

and

December

2010

Olympic-sized

swimming pool

entering the reservoir

every 3.5 seconds.

13


Risk Management

January

2010 storm

example

14


Risk Management

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 1997. 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.)

1

6

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

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.

18


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 2016.

19


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:

https://www.bchydro.com/energy-in-

bc/our_system/transmission_reservoir_data/hydrometric_data/vancouver_island.html.

https://www.bchydro.com/energy-in-bc/our_system/transmission_reservoir_data/hydrometric_data/vancouver_island.html







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)

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. .

22

Puntledge River - Water Gauges

Not shown:

• Gauge 10 at 5th

Street Bridge; and

• Gauge 11 at

Goose Spit Tidal

23

Communications With Water

Gauges & Warning System

24

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.

Puntledge River Hydroelectric System: Overviewforbiddenplateauroadassociation.com/images/Courtenay...5 Puntledge River System Fish flow requirements: Gauge 6 (below diversion dam)

Documents