Water Resources Operations Center(WROC)

Flood Damage Mitigation Through Reservoir Operation

Nov. 19, 2005. Kooyol Chong

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Flooding Flooding -- EuropeEurope

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Flooding Flooding -- USAUSA

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Flooding Flooding -- VietnamVietnam

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Flooding Flooding -- JapanJapan

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Flooding Flooding -- KoreaKorea

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An Efficient Structural SolutionAn Efficient Structural Solution

Reservoir

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Upstream of Dam

Downstream of Dam

Field Office

WROCWROC

Video Video ConferencingConferencing

Flood ReleasingFlood Releasing

Procedures of Flood Control Procedures of Flood Control

Forecasted Rainfall Observed Flood Situation

Runoff Analysis

Flood ReleaseSchedule

Flood ReleasingDissemination

Reservoir Simulation & Optimization

Water Resources Operations Center(WROC)

Procedures of Flood Control Procedures of Flood Control

Forecasted Rainfall

ObservedFlood Situation

Runoff Analysis

Flood ReleasingDissemination

Reservoir Simulation & Optimization

Flood ReleaseSchedule

1. Advance Release

2. Combined Reservoir Operation

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Flood Release ScheduleFlood Release Schedule

1. Advance Release

Why ? – Advance Release

Success ? – Advance Release

When ? – Trigger for Initiating

How much ? – Release Value Implemented

2. Combined Reservoir Operation Concept

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Exclusive Flood Storage Volume

Advance Release

Additional Flood Storage Volume

Exclusive Flood Storage Volume

Why ?Why ?Advance ReleaseAdvance Release

Advance Release

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Two extremes in Reservoir Operation

Given no information on future Inflow

�To maintain separate reservoir volumes for each function

Benefits of each function : Proportional to allocated volume

Having perfect foresight of Inflow

�Each reservoir function make use of total reservoir volume

Benefits of each function : Proportionally greater

Advance Release

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(1) (2)

(1) Advance Release(2) Failure to Refill

Success ?Success ?Advance Release (1)Advance Release (1)

Advance Release

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inflow

release

Reservoir capacity

Reservoir storage

Time

Stre

amflo

w, R

elea

se

Sto

rage

Vol

ume

Failure ?Failure ?Advance Release (2)Advance Release (2)

Advance Release

With Advance Release Without Advance Release

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1. A forecasted peak inflow of a certain value

2. A forecasted event volume of a certain value

Advance ReleaseWhen ?When ?Trigger for InitiatingTrigger for Initiating

3. A particular quantile of the forecasted event,

satisfying either trigger 1 or 2.

4. The forecasted event, causing a routed reservoir release

greater than channel capacity, without advance release

5. A particular probability of release exceeding channel

capacity without advance release

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Time

Stre

amflo

wBest-Estimate

ForecastHydrograph

25%exceed.

50%exceed.

75%exceedance

95%exceedance

99%ExceedanceProbabilityHydrograph

Time

Stre

amflo

wBest-Estimate

ForecastHydrograph

Advance Release Volume

99%ExceedanceHydrograph

Vfloodpool

MinVrelease

MaxVrelease

Advance ReleaseHow much ?How much ?Release Value ImplementedRelease Value Implemented

MinVrelease

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Hydrograph when release volume = 0

Combined Reservoir Operation

ConceptConceptDam 1

Dam 2

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Combined Reservoir Operation

SimulationSimulation

Dam 1

(A1)(B1)

(C1)

FWL

RWL

Dam 2

(A2)(B2)

(C2)

FWL

RWL

Index Value

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Combined Reservoir Operation

OptimizationOptimization

Where, H(l,t) : water level for each control point (each control point, l)

Dur(l,t) : duration when water level exceeds risk water level

for each control point

RWL(i,t) : penalty for specified water level of each dam (each dam, i)

Release(i,t) : penalty for released discharge for each dam

Objective FunctionObjective Function

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Thanks for your attention !Thanks for your attention !