2015 Hydro Operations from a Water Management & Stakeholder Perspective

CWRA Symposium January 29, 2016 Presentation Outline

Background on Bow River Hydro System

Detailed Look at 2015 Ghost Reservoir Operations – Water Management Issues – Stakeholder Issues Background on Bow Hydro System TransAlta Bow Hydro System - Reservoirs

Lake Minnewanka

Ghost Lake Majority of Storage Located on Tributary Rivers & High in the Basin

Barrier Lake Main Stem of Bow Spray Lake River Unregulated Upstream of Ghost

Upper & Lower Kananaskis Lakes TransAlta Bow Hydro System – Run of River

Minimal Ability to Regulate Flow

Whatever Flow Comes In Goes Out In Horseshoe Same Day Bearspaw Kananaskis Bearspaw Urban Legend Re: Flood Control Storage Comparison

Reservoir Storage Volumes 250

200

150

100 Millions Millions of Cubic Meters

50

0 Lake Spray Lake Upper Lower Kananaskis Horseshoe Bearspaw Minnewanka Kananaskis Kananaskis Lake Lake 2015 Ghost Reservoir Operating Agreement What Was The Background?

Joint Assessment by TransAlta & Environment & Sustainable Resource Development (now AEP) Building on Smaller Scale Pilot from 2014 Interim Focus on Flood Mitigation Acknowledged Longer Term Goal should be Comprehensive Water Management Started with Review of 2013 Operations Looked for Additional Opportunities 2013 Reservoir Operations

Corresponding Peak Reservoir Peak Inflow (m3/s) Date Release (m3/s) Minnewanka 440 June 20 6 Spray 360 June 20 18 Upper Kananaskis 80 June 20 0 Lower Kananaskis 110 June 20 0 Barrier 400 June 20 350 Ghost 1400 June 20 1400 Impact of Reservoir Operations on River Flows

Location Actual River Flow (m3/s) Natural River Flow (m3/s) Canmore 490 980 (u/s Elbow) 1840 2250 Conclusions From The Review

The Upstream Reservoirs (Minnewanka, Spray, Upper & Lower Kananaskis) already provide significant flood mitigation potential. Barrier Reservoir has very small storage capability even if empty. Short Term Focus would be on Ghost Reservoir opportunities. Ghost Reservoir Location Plan

Located 20 km West of Cochrane on Hwy 1A

At Confluence of Bow & Ghost Rivers

Constructed in 1929 Ghost Facility Details

Power House with 3 Turbine Units 54 MW Capacity

Concrete Main Dam with Earth Side Dams

Max Water Depth 32 m

Reservoir 12 km Long

Active Storage Volume = 57,000 AF or 70M cubic meters

Spillway Capacity = 5260 m3/s Ghost Reservoir Flood Mitigation Analysis

Prepared historic flood event inflow data into Ghost Reservoir and local inflow between Ghost and Bearspaw Chose different elevations for Ghost Reservoir at beginning of historic events Routed historic events through Ghost Reservoir & attempted to reduce peak flow through Calgary as much as possible City of Calgary – Bow River Flow Thresholds Bow River at Calgary Flow Reduction Using Ghost Reservoir

Bow River at Calgary Flow Reduction Modelling Results

Year Bow at Calgary Bow at Calgary Peak Flow (m3/s ) with best Recorded Peak Flows Reduction for Ghost Reservoir starting elevation: (m3/s ) 1185 m 1187 m 1189.4 m 1995 500 375 (125) 400 (100) 470 (30)

2005 790 510 (280) 530 (260) 650 (140)

2012 490 390 (100) 400 (90) 430 (60)

2013 1840 1450 (390) 1520 (320) 1660 (180)

Full Supply Level of Ghost Reservoir = 1191.8 m Calgary Peak Flow of 1450 m3/s = water level reduction of 42 cm or ~ 16 inches from actual 2013 level Basics of 2015 Ghost Reservoir Agreement

Established a Minimum Water Level for Allowable Drawdown (1184.2 m) Established a Control Period from May 15 – July 7, based on Dates of Historic Flood Occurrence Established a Protocol for AEP to Direct Operations Initial Reservoir Drawdown Commenced in April Major Drawdown Initiated on May 2 2015 Ghost Reservoir Levels

2015 Ghost Reservoir Levels Bow River Flows: 2015 vs. 2001

2001 Bearspaw Releases 2015 250

Refill Starts 200 Drawdown Ends June 13 May 24

150 Refill Ends July 2

100 Discharge (m3/s)

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Drawdown Starts May 3 0 01-Jan 31-Jan 02-Mar 01-Apr 01-May 31-May 30-Jun 30-Jul 29-Aug 28-Sep 28-Oct 27-Nov 27-Dec Challenges & Stakeholder Issues Isolated Pools Requiring Fish Salvage Isolated Pools Requiring Fish Salvage Boat Docks And Boat Ramps Public Safety Public Safety Water Wells

Summer Village of Ghost Lake

Concluding Observations (In No Particular Order)

Water Management Decisions Are Probably Going To Be Difficult & Time Consuming

Water Management Decisions Will Never Please Everybody

Water Management Decisions Should be Adaptive QUESTIONS? Ghost Reference Information