Water Management Section, Sacramento District, US Army Corps of Engineers Climate Impacts on...

Water Management Section, Sacramento District, Water Management Section, Sacramento District, US Army Corps of EngineersUS Army Corps of Engineers

Climate Impacts Climate Impacts on Reservoir on Reservoir Rule CurvesRule CurvesStu TownsleyStu Townsley

Chief, Water ManagementChief, Water Management

Sacramento DistrictSacramento District


Why I did this?Why I did this?

33 CFR 208.11(10) 33 CFR 208.11(10) Revisions. The water control planand all associated documents will berevised by the Corps of Engineers asnecessary, to reflect changed

conditionsthat come to bear upon flood controland navigation, e.g., reallocationof reservoir storage space due to

sedimentationor transfer of storage spaceto a neighboring project.


Pine Flat Flood Control Pine Flat Flood Control DiagramDiagram

Typical snowmelt influenced rule curve


0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000

Aug

Sep Oct

Nov

Dec Ja

n

Feb

Mar

Apr

May Ju

n

Jul

Rain Flood

Flood Control

Conditional Flood Space=f(snowpack, demands)

Rainflood Space

Flood Space

• Developed from historical record (look-back)• Conditional space dependent on B-120, irrigation demands• Operation based on observed data (rainfall, snow pillows)


Pine Flat OperationsPine Flat OperationsWY 2006

WY 1997WY 2004

WY 2005


Potential Flood Potential Flood ImplicationsImplications

Literature suggestsLiterature suggests Warmer regime, about the same Warmer regime, about the same

annual precipitationannual precipitation Smaller snowpack, earlier melt, Smaller snowpack, earlier melt,

flow shiftflow shift Greater storm variability/intensityGreater storm variability/intensity

Implications?Implications? Need more rainflood space?Need more rainflood space? Allow earlier fill?Allow earlier fill?


Snowmelt TrendsSnowmelt Trends

USGS Fact Sheet 2005-3018Michael DettingerU.S. Geological SurveyScripps Institution of Oceanography


Mean Snowmelt PeakMean Snowmelt PeakFull Natural FlowsFull Natural Flows

1-Feb

8-Feb

15-Feb

22-Feb

1-Mar

8-Mar

15-Mar

22-Mar

29-Mar

5-Apr

12-Apr

19-Apr

26-Apr

3-May

10-May

17-May

24-May

31-May

7-Jun

1940 1950 1960 1970 1980 1990 2000 2010

Shasta

Oroville

New Bullards

Mean Snowmelt Peak Day Shasta Oroville New Bullards

Period of Record 2-Apr 20-Apr 22-Apr

Last 20 years 3-Apr 15-Apr 16-Apr


San Joaquin ReservoirsSan Joaquin ReservoirsElevation PercentagesElevation Percentages

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2500 5000 7500 10000 12500 15000

Elevation (ft)

% E

leva

tio

n b

elo

w

NEW_HOGAN

FARMINGTON

NEW_MELONE

TULLOCH

DON_PEDRO

EXCHEQUER

BURNS

BEAR

OWENS

MARIPOSA

BUCHANAN

HIDDEN

FRIANT

PINE_FLAT

TERMINUS

SUCCESS

ISABELLA

LOS_BANOS

BIG_DRY

CAMANCHE

N58% below 6500’

New Melones38% below 5000’

EqualsEquals20% between20% between5000 ft and 6500 ft5000 ft and 6500 ft


ShastaShasta (purple = (purple =

5000<elev<6500)5000<elev<6500)


New BullardsNew Bullards (purple = (purple =

5000<elev<6500)5000<elev<6500)


Oroville Oroville DrainageDrainage

(purple = (purple = 5000<elev<6500)5000<elev<6500)


Sacramento Reservoir Sacramento Reservoir Elevation PercentagesElevation Percentages

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2500 5000 7500 10000

ENGLEBRIGH

NEW_BULLAR

FOLSOM

BLACK_BUTT

INDIAN_VAL

OROVILLE

% of basin between 5000 and 6500 ftShasta 34%Oroville 50%New Bullards 33%


New BullardsNew BullardsData SetData Set 1% Inflow1% Inflow

(1000 cfs)(1000 cfs)

FullFull 9595

Last 30 Last 30 yearsyears

125125

Model 07 Model 07 (T) 2011-40(T) 2011-40

150150

Model 07 Model 07 (T) 2041-70(T) 2041-70

140140

Model 07 Model 07 (T) 2071-(T) 2071-21002100

150150


OrovilleOrovilleData SetData Set 1% Inflow1% Inflow

1000 cfs1000 cfs

FullFull 300300

Last 30 Last 30 yearsyears

370370

Model 03 Model 03 (P) 2011-40(P) 2011-40

370370

Model 07 Model 07 (T) 2041-70(T) 2041-70

320320

Model 10 Model 10 (T) 2071-(T) 2071-21002100

370370


OrovilleOrovilleoperations under operations under climate adjusted climate adjusted

inflowsinflowsE

ElevationRelease


Climate adjusted Climate adjusted diagram ?diagram ?

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000

1-A

ug

1-S

ep

1-O

ct

1-N

ov

1-D

ec

1-J

an

1-F

eb

1-M

ar

1-A

pr

1-M

ay

1-J

un

1-J

ul

Rainflood Space

Flood Space

ConditionalSpace

Jury still out – takes studies to Jury still out – takes studies to resolve!resolve!


What next?What next?

GivenGiven Climate change (mean is changing)Climate change (mean is changing) Climate variability (variance is increasing)Climate variability (variance is increasing)

Need better climate models at Need better climate models at watershed scalewatershed scale

Increased process-based, distributed Increased process-based, distributed analysisanalysis

Less reliance on current statistical toolsLess reliance on current statistical tools Move to adaptive rule curves?Move to adaptive rule curves?


Adaptive curvesAdaptive curves

Current rule curvesCurrent rule curvesStorage = f( inflow, channel Storage = f( inflow, channel capacity, measured precip, forecast capacity, measured precip, forecast snowmelt, forecast demand)snowmelt, forecast demand)

Potential curvesPotential curvesStorage = f( above Storage = f( above plusplus short-term weather forecast, mid-range climate forecast, advanced release, and ???)


Questions?Questions?

Water Management Section, Sacramento District, US Army Corps of Engineers Climate Impacts on...

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