TDG UPDATE

Dan TurnerWater Quality Team LeadReservoir Control Center10 May 2019

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The DallesDam

Spillway

Power house

TDAtailwatergauge

TDA Forebaygauge

John Day Dam

Spillway

Power house

JDA Forebaygauge

JDA tailwater gauge

121.3%

120.8%

119.8%

117.8%40%

60%

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OTHER FACTORS CONSIDERED: DEGASSING

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105

110

115

120

125

130

135

4/10/2018 4/20/2018 4/30/2018 5/10/2018 5/20/2018 5/30/2018 6/9/2018 6/19/2018

TDG

(% sa

tura

tion)

The Dalles Dam

Tailwater gauge Forebay gauge

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The Dalles tailwater elevation (average = 79.7 feet)

Bonneville forebay elevation (average = 74.3 feet)

BONNEVILLE FOREBAY & THE DALLES TAILWATER

NOTE: Bonneville Dam forebay normal operating range = 71.5 - 76.5 feet

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Bonneville inflow forecast• May 10-19• Range: 260-340 kcfs• Average: 300 kcfs

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BON inflow = 300 kcfs• BON forebay avg = 74.3 ft• BON forebay decrease by

2 feet to 72.3 ft• BON forebay decrease of

2 feet = TDA tailwater decrease of 1.4 feet

BON inflow = 400 kcfs• BON forebay decrease of

2 feet = TDA tailwater decrease of 1.1 feet

BON inflow = 200 kcfs• BON forebay decrease of

2 feet = TDA tailwater decrease of 1.7 feet

76.5

71.5