Oroville Reservoir Inflow Forecasting Using the HED-71 Inflow Forecast Model Mock Scenario: LATE DECEMBER 2005 STORMS Dave Rizzardo, PE Chief, Forecasting.

Oroville Reservoir Inflow Forecasting Oroville Reservoir Inflow Forecasting Using the Using the

HED-71 Inflow Forecast ModelHED-71 Inflow Forecast Model

Mock Scenario:Mock Scenario:LATE DECEMBER 2005 STORMSLATE DECEMBER 2005 STORMS

Dave Rizzardo, PEDave Rizzardo, PEChief, Forecasting SectionChief, Forecasting Section

Hydrology BranchHydrology BranchDWR - Division of Flood ManagementDWR - Division of Flood Management

HED-71 Inflow Forecast Model HED-71 Inflow Forecast Model FactsFacts

• Originally Developed in early 1970s (1971 perhaps?) by DWR and NWS Forecasters

(Bob Burnash and Larry Ferral)

• Converted to current FORTRAN “interactive” format by Gary Hester and Jack Grewal

• Late 1980s added feature of simulating soil infiltration capacity recovery during dry periods

HED-71’s StrengthsHED-71’s Strengths

• Simple and easy to use and learn

• Provides relatively quick results

• Simple input (precipitation, freezing elevations, etc) and principles (unit hydrograph for each basin)

• Can be used on almost any headwater basin within California (53 total basins are configured)

• In the hands of a skilled forecaster, HED71 will yield excellent results over a wide range of storm conditions

HED-71’s WeaknessesHED-71’s Weaknesses

• Does not handle long dry periods well (Must “start a new storm”)

• FORTRAN code is old and limited

• Interface is DOS based – not easy to navigate to make corrections

• Tends to melt existing snow pack too quickly requiring savvy modeler to “tame” springtime heat spells

• Anticedence Index input (soil moisture) is a bit ambiguous

HED-71’s InputHED-71’s Input

• Observed or Forecasted Precipitation (inches)

• Observed Flow (if known) (tcfs)

• Observed or Forecasted Freezing Elev. (ft)

Base Conditions:• Current Date, time

• Antecedence Index

• Base Flow (tcfs)

• Snow Pack (swc - in.) per elevation band6-Hourly

Input:

HED-71’s InputHED-71’s InputFeather River Precipitation and Temperature Forecast:

Day Date Precip Snow Level

No. (inches) (feet) Precip Snow Depth Min Temp

(inches) (inches) (F)

Sunday, January 01, 2006 2.2 6,000 0.2 2 23

1 Monday, J anuary 02, 2006 2.0 5,000 0.3 2 23

2 Tuesday, J anuary 03, 2006 0.5 4,000 0.3 2 23

3 Wednesday, J anuary 04, 2006 0.4 4,500 0.3 2 23

4 Thursday, J anuary 05, 2006 0.0 8,500 0.3 2 23

5 Friday, J anuary 06, 2006 0.0 9,000 0.3 2 23

6 Saturday, J anuary 07, 2006 0.0 7,500 0.3 2 23

7 Sunday, J anuary 08, 2006 0.0 7,500 0.3 2 23

8 Monday, J anuary 09, 2006 0.0 5,000 0.3 2 23

9 Tuesday, J anuary 10, 2006 0.2 5,000 0.3 2 23


Thursday, J anuary 12, 2006 0.0 5,000 0.3 2 23

10-Day Total: 3.1 2.6

10-Day Percent of Normal: 120%

10-Day Feather Basin QPFSunday, J anuary 01, 2006

(each day ends at 0400 PDT)

Average Daily*

Provided daily by State or NWS Meteorologists

HED-71’s HED-71’s InterfaceInterface

Antecedence Index and Base Flow Parameters are

entered after date and time. Both are

estimates.Snow Water Content (SWC) is then added for every elevation band from 1000’ to 14000’ if applicable.

SWC is estimated for the Feather Basin from snow pillows at:

Rattlesnake

Four Trees

Bucks Lake

Humbug Summit


Once Base conditions are in…

..it is time to update the model with the forecasted values from the meteorologists.

First – a few days of observed precipitation, inflow, and temperatures are put into the model to “warm up” the model

Next – 6-hourly precipitation and freezing elevations are put into the model (4 inputs per day) for the 10-day forecast period.


Then the model is executed and results are printed on the screen for quick review..

Verify SWC InputVerify Precipitation and Elevation Input

Now Evaluate Model results..

Does forecasted inflow make sense?

Does forecast agree with other models (RFC 5-Day Forecast, ESP Snow Melt Model, etc)?


Problems noted?!?• Re-examine Input

• Too Much or Too Little Precipitation?

• Melting too fast – moderate temperatures

• Antecedence conditions too wet or dry? Raise or lower A.I.

• Too much or too little snow pack? Adjust amounts as needed.

December 2005 December 2005 Inflow ScenarioInflow Scenario Four warm winter Four warm winter

storms laden with storms laden with tropical moisturetropical moisture

December Northern December Northern Sierra 8-Stations total Sierra 8-Stations total precipitation: 26”precipitation: 26”

310% of average310% of average

44thth wettest December wettest December on recordon record

December 15, 2005December 15, 2005Very Little Precipitation forecast for next 10-days! Merry Christmas indeed!




Thursday, December 15, 2005 0.0 8,500 0.2 1 25

1 Friday, December 16, 2005 0.0 8,000 0.2 1 25

2 Saturday, December 17, 2005 0.0 7,000 0.2 1 25

3 Sunday, December 18, 2005 0.1 5,500 0.2 1 25

4 Monday, December 19, 2005 0.3 6,000 0.2 1 24

5 Tuesday, December 20, 2005 0.0 7,000 0.2 1 24

6 Wednesday, December 21, 2005 0.0 8,500 0.2 1 24

7 Thursday, December 22, 2005 0.2 7,000 0.2 1 24

8 Friday, December 23, 2005 0.0 8,000 0.2 1 23


10 Sunday, December 25, 2005 0.2 9,000 0.2 1 23

Monday, December 26, 2005 0.0 9,000 0.2 1 23

10-Day Total: 0.8 2.3

Thursday, December 15, 2005(each day ends at 0400 PDT)

Average Daily*

October Total: 1.5 " Percent of October Average: 50%

October Average: 3.0 "

November Total: 6.4 " Percent of November Average: 102%

November Average: 6.3 "

Monday, December 12, 2005 0.0"

December to Date (revised): 4.5 " Percent of Monthly December Average: 54%

December Monthly Average: 8.4 "

Seasonal Total to Date: 12.4 " Percent of Seasonal Average to Date: 93%

Seasonal Average to Date: 13.4 "

Water Year Average 50.0 " Percent of an Average Water Year: 25%

Northern Sierra 8-Station Precipitation (inches)Water Year 2006

Thursday, December 15, 2005

Total precipitation since

Dec. precip. by 12/15:

4.5” for 54% of Dec. Avg.

December 27, 2005December 27, 2005Conditions changed quickly – after two wet storms had already passed, we were now expecting at least two more by New Year’s!

Dec. precip. by 12/27:





Saturday, December 24, 2005 0.0 0.2 1 23

Sunday, December 25, 2005 0.0 9,000 0.2 1 23

Monday, December 26, 2005 1.2 6,000 0.2 1 23

Tuesday, December 27, 2005 0.2 5,000 0.2 1 23

1 Wednesday, December 28, 2005 1.8 8,000 0.2 1 23

2 Thursday, December 29, 2005 2.4 6,000 0.2 1 23

3 Friday, December 30, 2005 0.1 4,500 0.2 2 23


5 Sunday, J anuary 01, 2006 0.7 5,000 0.2 2 23

6 Monday, J anuary 02, 2006 1.7 4,000 0.3 2 23

7 Tuesday, J anuary 03, 2006 0.2 4,000 0.3 2 23



10 Friday, J anuary 06, 2006 0.1 5,500 0.3 2 23

Saturday, J anuary 07, 2006 0.1 5,000 0.3 2 23

10-Day Total: 10.0 2.5


10-Day Feather Basin QPFTuesday, December 27, 2005(each day ends at 0400 PDT)

Average Daily*





Friday, December 23, 2005 3.0"

December to Date: 16.4 " Percent of Monthly December Average: 195%






Tuesday, December 27, 2005


January 1, 2006January 1, 2006Happy New Year’s! When it was all said and done….The last hurrah came on

New Year’s day

Total December ’05 Precip:


.. or over 21” in two weeks!!




Saturday, December 31, 2005 5.8 7,500 0.2 2 23

1 Sunday, J anuary 01, 2006 2.5 6,000 0.2 2 23

2 Monday, J anuary 02, 2006 1.7 5,000 0.3 2 23

3 Tuesday, J anuary 03, 2006 0.4 4,000 0.3 2 23



6 Friday, J anuary 06, 2006 0.1 8,000 0.3 2 23

7 Saturday, J anuary 07, 2006 0.1 7,000 0.3 2 23

8 Sunday, J anuary 08, 2006 0.0 5,000 0.3 2 23

9 Monday, J anuary 09, 2006 0.0 5,000 0.3 2 23

10 Tuesday, J anuary 10, 2006 0.0 5,000 0.3 2 23

Wednesday, J anuary 11, 2006 0.0 6,000 0.3 2 23

10-Day Total: 4.8 2.6


Saturday, December 31, 2005(each day ends at 0400 PDT)

Average Daily*





December to Date: 25.8 " Percent of Monthly December Average: 307%


Saturday, December 31, 2005 0.5"

January to Date: 0.5 " Percent of Monthly January Average: 6%






Sunday, January 01, 2006


How did HED-71 How did HED-71 Do?Do? Not bad at

all!• Predicted a peak inflow of almost 122,000 cfs into Lake Oroville

Observed was 127,000 cfs

Overall HED71 missed peak daily values, but modeled the trend of the inflow fairly well. Much credit to the meteorologists on this!

HYDROLOGY – Reservoirs - HYDROLOGY – Reservoirs - OrovilleOroville Storage before:Storage before:2,795 2,795

TAFTAF Storage after:Storage after: 2,849 TAF2,849 TAF Inflow:Inflow: 483 TAF483 TAF Outflow:Outflow: 431 TAF431 TAF Lake elevation:Lake elevation: +10 feet+10 feet Peak inflow:Peak inflow: 166,540 cfs166,540 cfs Peak inflow ’97:Peak inflow ’97:302,000 302,000

cfscfs

(TAF = thousand acre feet)(TAF = thousand acre feet)

HYDROLOGY–Rivers–Sacramento - HYDROLOGY–Rivers–Sacramento - StageStage

High Water EventsHigh Water Events

StationStation 2005 – 062005 – 06(feet) (feet)

19971997(feet)(feet)


Bend Bend BridgeBridge

30.130.1 30.630.6 32.832.8

Tehama Tehama BridgeBridge

220.0220.0 221.2221.2 220.1220.1

Hamilton Hamilton CityCity

149.7149.7 150.9150.9 150.5150.5

Ord FerryOrd Ferry 117.7117.7 118.7118.7 118.3118.3

Fremont Fremont WeirWeir

39.939.9 42.542.5 41.741.7

I Street I Street BridgeBridge

27.727.7 30.430.4 30.730.7

Rio VistaRio Vista 10.610.6 11.211.2 11.511.5

Sacramento Weir - Jan 3, 2006

HYDROLOGY– Rivers – Feather - HYDROLOGY– Rivers – Feather - StageStage

High Water EventsHigh Water Events

StationStation 2005 – 062005 – 06(feet) (feet)



Yuba CityYuba City 68.468.4 78.278.2 76.376.3

NicolausNicolaus 45.945.9 50.450.4 49.149.1

3-day precipitation data return 3-day precipitation data return periods (yrs):periods (yrs): Upper Sacramento RiverUpper Sacramento River1 in 51 in 5 Feather RiverFeather River 1 in 51 in 5 Yuba RiverYuba River 1 in 51 in 5 American RiverAmerican River 1 in 51 in 5

RESPONSE RESPONSE

December 27, 2005 – DWR Flood AlertDecember 27, 2005 – DWR Flood Alert Extended hours at the State-FederalExtended hours at the State-Federal Flood Operations Center (FOC)Flood Operations Center (FOC) Increased flood information processingIncreased flood information processing High water notification calls made to pertinent agenciesHigh water notification calls made to pertinent agencies Increased readiness to facilitate flood fight efforts if neededIncreased readiness to facilitate flood fight efforts if needed

December 29, 2005 – DWR Flood MobilizationDecember 29, 2005 – DWR Flood Mobilization FOC staffed 24/7FOC staffed 24/7 DWR in conjunction with the NWS produced river forecast DWR in conjunction with the NWS produced river forecast

bulletins every six hoursbulletins every six hours DWR levee inspectors patrolled 24/7 in State Maintenance DWR levee inspectors patrolled 24/7 in State Maintenance

AreasAreas State funds were made available for materials, emergency State funds were made available for materials, emergency

equipment, and for personnel working on flood operationsequipment, and for personnel working on flood operations About 200 DWR staff, 4 CDF crews, and * CCC crews were About 200 DWR staff, 4 CDF crews, and * CCC crews were

ultimately involved in the eventultimately involved in the event

QUESTIONS?QUESTIONS?

Oroville Reservoir Inflow Forecasting Using the HED-71 Inflow Forecast Model Mock Scenario: LATE DECEMBER 2005 STORMS Dave Rizzardo, PE Chief, Forecasting.

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