Pierre Dupuis, ing.

Canada

J.Dumas, D.Messier, S.Weyman

7th International Conference on Hydro informatics

HIC 2006 Nice, France

Impacts Assessment of the Rupert River diversion on

Rupert Bay Estuary Hydrodynamics

PlanPlan

Eastmain 1A – Rupert river diversion projectEastmain 1A – Rupert river diversion project– Impacts assessment study required Impacts assessment study required

2D modeling of Rupert Bay hydrodynamics2D modeling of Rupert Bay hydrodynamics– Strategy for this studyStrategy for this study– Data acquisition and analysisData acquisition and analysis– Input to model Input to model – Productivity tools used for impact assessmentsProductivity tools used for impact assessments– Results Results

ConclusionConclusion

Eastmain-1-A Project Eastmain-1-A Project Province de Québec, Province de Québec, CanadaCanada

Montréal

Hudson Bay

James Bay

Great Lakes

Rupert Bay

La Grande HydroelectricComplex

Eastmain-1-A Powerhouse

DiversionDiversion

Rupert Bay

DiversionEastmain-1-A

La Sarcelle

La Grande-2-A

La Grande 1

Eastmain-1-A ProjectEastmain-1-A Project

Estimated cost: 2 500 millions Estimated cost: 2 500 millions €€ Added Power : 768 MW + 120 MWAdded Power : 768 MW + 120 MW Added Annual Energy: 8,5 TWhAdded Annual Energy: 8,5 TWh Diversion: 452,6 mDiversion: 452,6 m33/s mean annual /s mean annual

flow, max: 800 mflow, max: 800 m33/s/s Less fresh water inflow in Rupert Less fresh water inflow in Rupert

BayBay In commission: 2011In commission: 2011

Objectives and Objectives and constraintsconstraintsRupert Bay Rupert Bay hydrodynamicshydrodynamics Get a good understanding of the bay Get a good understanding of the bay

actual hydrodynamic conditionsactual hydrodynamic conditions Assess the impacts of less freshwater Assess the impacts of less freshwater

inflow into the bay inflow into the bay Make sure the study is credible and Make sure the study is credible and

will be well received by the public and will be well received by the public and govern-mental agencies (federal and govern-mental agencies (federal and provincial)provincial)

Proceed according to an established Proceed according to an established time frame and within budget!time frame and within budget!

Rupert bay & Rupert bay & WaskaganishWaskaganish

James Bay

Rupert Bay

Stag Rock

WaskaganishCree Native community

17,5 kmStag Island

WaskaganishWaskaganish

Rupert Bay Rupert Bay CharacteristicsCharacteristics

Covers 825 kmCovers 825 km22

Width of the bay varies from 10 to Width of the bay varies from 10 to 18 km18 km

Channel depth varies from 5 to 8 mChannel depth varies from 5 to 8 m Tidal amplitude: 2 mTidal amplitude: 2 m Salinity of 20-22 Salinity of 20-22 ‰ in James Bay‰ in James Bay

ZonesZones

MaritimeMaritime MixingMixing

FreshwateFreshwaterr Pontax

Rupert

Broadback

Nottaway

Cabbage Willows – Tidal Cabbage Willows – Tidal FlatsFlats

ModelingModeling

Numerical modeling is requiredNumerical modeling is required– Huge area, low depth, bathymetryHuge area, low depth, bathymetry

Hydro-Québec chose Mike21Hydro-Québec chose Mike21™ from DHI ™ from DHI (Danish Hydraulic Institute)(Danish Hydraulic Institute)– Accepted within the scientific communityAccepted within the scientific community– Well mixed estuaryWell mixed estuary– Modules HD and ADModules HD and AD

Strategy: Simulation of 7 weeks in summerStrategy: Simulation of 7 weeks in summer– Natural conditionsNatural conditions– Post diversion conditionsPost diversion conditions

Simulation of 4 weeks in winterSimulation of 4 weeks in winter

Required input dataRequired input data

BathymetryBathymetry Downstream boundary tidal Downstream boundary tidal

signalssignals Fresh water inflowsFresh water inflows

Bathymetry Bathymetry

Parallel lines every 200 mParallel lines every 200 m GPS positioningGPS positioning

– Correction for tidal influenceCorrection for tidal influence– Crosscheck with perpendicular linesCrosscheck with perpendicular lines

Vertical precision estimated at 10 cmVertical precision estimated at 10 cm Very shallow waters and tidal flats: Very shallow waters and tidal flats:

Airborne LaserAirborne Laser Took 2 summers to complete workTook 2 summers to complete work Cost: 675 000 Cost: 675 000 €€

Final resultFinal result

Rupert

Broadback

Nottaway

James Bay

Warm colors: shallow depthMany channels within the bay

Pontax

Tidal Tidal gaugesgauges BoundariesBoundaries

– MesaconanMesaconanee

– StruttonStrutton WithinWithin

– Gushue Gushue IslandIsland

– Stag rockStag rock– Rupert riverRupert river– LemoyneLemoyne

Conditions aux limites pour calibration - Marée 1991

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

1991-06-1300:00

1991-06-1500:00

1991-06-1700:00

1991-06-1900:00

1991-06-2100:00

1991-06-2300:00

1991-06-2500:00

1991-06-2700:00

1991-06-2900:00

1991-07-0100:00

1991-07-0300:00

Date

Niv

eau

d'e

au [

m]

Iles Strutton Pointe Mésaconane

June 13 1991 July 3

2 m

0 m

-2 m

1 m

-1 m

Boundary conditions for calibration - 1991

Tidal signalsTidal signalsConditions limites aux frontières aval

Été 2003

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

2003-08-07 2003-08-17 2003-08-27 2003-09-06 2003-09-16 2003-09-26 2003-10-06 2003-10-16 2003-10-26

Date

Niv

eau

d'e

au

Pointe Mésaconane Ile Strutton

3 m

0 m

-2 mAugust 7th 2003 October 20th

Tidal signal at downstream boundary for modeling

Super storm of August 22, 2003

Fresh water inflow in Fresh water inflow in summer total: 2500 to 3000 summer total: 2500 to 3000

mm33/s /s (summer 2003)(summer 2003)

Débits d'apport - Été 2003

0

200

400

600

800

1000

1200

1400

1600

2003-0

8-0

1

2003-0

8-0

8

2003-0

8-1

5

2003-0

8-2

2

2003-0

8-2

9

2003-0

9-0

5

2003-0

9-1

2

2003-0

9-1

9

2003-0

9-2

6

2003-1

0-0

3

2003-1

0-1

0

2003-1

0-1

7

2003-1

0-2

4

2003-1

0-3

1

Déb

it m

3/s

Nottaway Broadback Ruper naturel Pontax Rupert post dérivation

Nottaway

Pontax

Broadback Rupert post diversion

Rupert natural state

August 1 October 31

1600 m3/s

800 m3/s

0 m3/s

Data acquisition costs Data acquisition costs ((€€))

Bathymetry: Bathymetry: 675 000 675 000 €€ Oceanography: Oceanography: 640 000 640 000 €€ Stations (material & install)Stations (material & install) 255 255

000 000 €€ Maintenance (5 years)Maintenance (5 years) 250 000 €250 000 € HelicoptersHelicopters 250 000 €250 000 €

Total :Total : 2 070 000 € 2 070 000 €

DomainDomain

Cell: square 162 mCell: square 162 m GridGrid

– 625 rows625 rows– 370 columns370 columns

Chézy coefficient Chézy coefficient for calibrationfor calibration– Tidal rangeTidal range– Signal deformationSignal deformation

Time step: 90 sTime step: 90 s Output: 15 minutesOutput: 15 minutes

Calibration Calibration

Winter : 35Winter : 35 Summer : 65Summer : 65

Validation Rupert Validation Rupert RiverRiver

Km 2,5Km 4,2

Impacts assessmentImpacts assessment

2 Output files of 2 Output files of 15 Gb15 Gb to work with to work with– NTFS file system required to store and NTFS file system required to store and

access output dataaccess output data– Special C++ module for retrieving dataSpecial C++ module for retrieving data– Read directly from binary output files Read directly from binary output files

(Mike21 output file of type *.dfs2)(Mike21 output file of type *.dfs2)– Can work on matrices (matrix operators)Can work on matrices (matrix operators)

15Gb was a workable up limit for file 15Gb was a workable up limit for file sizesize

ToolsToolsSubtractions Subtractions and and comparisonscomparisons

Subtracts Subtracts post post diversiondiversion from from naturalnatural at any at any given time stepgiven time step

Do water level Do water level variation for a variation for a given cell over a given cell over a given time period given time period and compare to and compare to field data – Quick field data – Quick for validation for validation purposespurposes

ToolsToolsExtremaExtrema

Public and policy Public and policy makers cannot makers cannot always be in always be in front of the front of the screenscreen

Example:Example: Maximum speed Maximum speed

modulus for a modulus for a five weeks five weeks period for pre period for pre and post and post diversion diversion conditionsconditions

ToolsToolsVirtual Virtual probeprobe

Set start date and Set start date and locationlocation

Monitors current Monitors current speed, depth, timespeed, depth, time

Helps to:Helps to:– understand understand

circulation patternscirculation patterns– Zones affected by Zones affected by

each streameach stream

Impact of Impact of diversiondiversion White: NaturalWhite: Natural Black: Post Black: Post

diversiondiversion• Less lateral flow Less lateral flow

pressure from pressure from Rupert River Rupert River

• Flow from Nottaway Flow from Nottaway and Broadback will and Broadback will shift toward the shift toward the East.East.

Time of residenceTime of residence

Before diversion After diversion

8 days 12 days

Start

History of a virtual History of a virtual probeprobe

Before diversion After diversion

Duration in days 0-30

Duration in days 0-25

Travel distance 0-900 km

Travel Distance 0-1100 km

1,4 m/s

0 m/s

SpeedSpeed

Azimuth Azimuth

Salinity - ModelingSalinity - Modeling

Time step reduced from 90 to 45 sTime step reduced from 90 to 45 s Salinity was set constant at 20 Salinity was set constant at 20 ‰ at ‰ at

downstream boundariesdownstream boundaries Fresh water threshold : 0,5 Fresh water threshold : 0,5 ‰‰ Advection-Dispersion coefficient set to Advection-Dispersion coefficient set to

130130 Results showed very good agreement Results showed very good agreement

with measurements at Stag Island and with measurements at Stag Island and Stag RockStag Rock

Fresh water Fresh water frontfront

Samples taken Samples taken from from helicopter to helicopter to follow frontfollow front

For large and For large and small tidessmall tides

Used for Used for calibrationcalibration

Salinity - ModelSalinity - ModelExtreme incursion and excursionExtreme incursion and excursionFrom Sept 1From Sept 1stst to October 11 to October 11thth 2003 2003

SalinitySalinityImpactsImpacts Translation of the Translation of the

freshwater front freshwater front upstream due to upstream due to diversiondiversion

Translation Translation estima-ted to be 4 estima-ted to be 4 to 5 kmto 5 km

Waskaganish is Waskaganish is still in the fresh still in the fresh water zonewater zone

Before diversion

Winter - Ice field and Winter - Ice field and fluxflux

Impact at Impact at WaskaganishWaskaganish

Imbricated Imbricated modelmodel

Cell: 54 mCell: 54 m Water Water

levelslevels Flats (low Flats (low

tide)tide) CurrentsCurrents

Conclusion - 1Conclusion - 1

Study constrained by cost and time scheduleStudy constrained by cost and time schedule Data requirements to be planned in advanceData requirements to be planned in advance

– Stations carefully located and justifications well Stations carefully located and justifications well explained to project administratorexplained to project administrator

– Types of instruments, number of stations, location and Types of instruments, number of stations, location and purpose well documentedpurpose well documented

– Stations maintenance and checkup to be included in Stations maintenance and checkup to be included in costscosts

– Modeler has to go to the site to get a feel of the system Modeler has to go to the site to get a feel of the system and must be part of the data gathering teamand must be part of the data gathering team

Real conditions simulated over a long time Real conditions simulated over a long time period are well received by the public and period are well received by the public and governmental agenciesgovernmental agencies

Conclusion - 2 Conclusion - 2

Tools are needed to synthesize and Tools are needed to synthesize and represent results in a suitable form for represent results in a suitable form for other scientists and the public other scientists and the public

Interaction between the modeler and Interaction between the modeler and specialists led to development of specialists led to development of numerical tools to address their specific numerical tools to address their specific demandsdemands

Once created, these tools helped in Once created, these tools helped in producing final results in a short time span producing final results in a short time span when all field measurements were when all field measurements were available (near the project deadline)available (near the project deadline)

This PowerPoint presentation can be downloaded from this site in the near future

http:://www.aquapraxis.com/nice2006

Broadback River Broadback River channelchannel

SalinitySalinityImpactImpact

Salinité chenal est - Différences pré et post dérivation

00.10.20.30.40.50.60.70.80.9

11.11.21.31.41.51.61.71.81.9

22.12.22.32.42.52.62.72.82.9

3

2003-09-02 2003-09-03 2003-09-04 2003-09-05 2003-09-06 2003-09-07 2003-09-08 2003-09-09 2003-09-10 2003-09-11

Date

Différe

nce de

salini

té [ppm

]

SE1 SE2 SE3 SE4 SE5

Salinity – MeasurementsSalinity – MeasurementsStag Rock (moored Stag Rock (moored station)station)

Depth 4,0 – 6,5 m

Salinity 0 - 4 ‰

Conductivity 0 – 6

Current speed 0,0 – 0,8 m/s

Current direction

Julian day

Impacts - SummerImpacts - Summer

Fresh water inflow will drop by 20 to 25% Fresh water inflow will drop by 20 to 25% Fluvial circulation will shift toward the north-Fluvial circulation will shift toward the north-

east (less pressure from Rupert River)east (less pressure from Rupert River) Residency time in the Residency time in the freshwater freshwater zone is one zone is one

to two days longer in summer timeto two days longer in summer time Salinity front will translate Salinity front will translate ≈ 4-≈ 4-5 km southward5 km southward Salinity changes from 0,5 Salinity changes from 0,5 ‰ to 1,0 ‰ in the ‰ to 1,0 ‰ in the

vicinity of Stag Rockvicinity of Stag Rock No perceptible variations within the bay as for No perceptible variations within the bay as for

water levels (in terms of mm) and velocity from water levels (in terms of mm) and velocity from a user standpointa user standpoint

Piston like effect in James bay moves water Piston like effect in James bay moves water within the bay toward the Westwithin the bay toward the West

Impacts - WinterImpacts - Winter

Fresh water inflow will drop by 20 %Fresh water inflow will drop by 20 % Time of residence is much longerTime of residence is much longer Effects from diversion are of lesser importanceEffects from diversion are of lesser importance Incursion-excursion of fresh water front is within Incursion-excursion of fresh water front is within

the limits established for summerthe limits established for summer Corroborates the findings of Ingram (1977)Corroborates the findings of Ingram (1977)

Possible explanationPossible explanation System is in a dormant state in winterSystem is in a dormant state in winter

– More frictionMore friction– Less fresh water inflowLess fresh water inflow– Tidal amplitudes of lesser magnitudeTidal amplitudes of lesser magnitude