Omaha Districts Inflow Forecast Regression Analysis

US Army Corps of EngineersBUILDING STRONG®

Omaha Districts Inflow Forecast Regression Analysis

Carrie Vuyovich and Steven DalyERDC-CRRELCold Regions Res. and Engr. Lab. (CRREL)U.S. Army Corps of Engineers

January 2011

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Overview

Background Multiple linear regression analysis to forecast spring

inflows to reservoirs 6 snow-dominated watersheds Monthly forecasts beginning in January

Goals Update regressions with recent data, improve accuracy Develop better estimate of SWE Work towards a more automated process Identify possible climate trends

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Parameters

• Q (106 ac-ft) = Forecasted total volume inflow to reservoir (+ Holdouts)

• SWE (in) = Average station SWE on first of month• ANTQ (106 ac-ft) = Total antecedent inflow from Oct – Nov of previous year

(+ Holdouts)

• ANTPREC (in) = Total annual precipitation in previous year

• P (in) = Total precipitation since beginning of year

1 1

1 1

OCT NOV DEC OCT

OCT NOV OCT NOV

APR JUL APR JUL AUG APR

APR JUL APR JUL

Holdout Storage Storage Storage

AntQ Inflow Holdouts

Holdout Storage Storage Storage

Q Inflow Holdouts

Holdout Calculation:

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Canyon Ferry

Average monthly total precipitation (in)

Area = 15,886 mi2

Average Apr-Jul total volume inflow = 1.9 M ac-ft (2 M ac-ft Natural)

Average Oct-Nov total volume inflow = 0.56 M ac-ft (0.56 M ac-ft Natural)

Precip (in) Jan Feb Mar Apr May JunAverage 0.56 0.46 0.89 1.41 2.30 2.49

SWE (in) 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-JunAverage 7.35 10.65 13.32 16.59 16.87 8.84

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Canyon Ferry

0.00

0.50

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Canyon Ferry1 Jan Forecast

Actual inflow Observed Natural Inflow

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Canyon Ferry1 Feb Forecast


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Canyon Ferry1 Mar Forecast


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Canyon Ferry1 Apr Forecast


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Canyon Ferry1 May Forecast


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1970

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Canyon Ferry1 June Forecast


Jan Feb Mar Apr May June JulyResults Without Holdouts R2 0.43 0.55 0.55 0.63 0.71 0.75 0.84

Std dev error 0.66 0.60 0.61 0.55 0.49 0.45 0.37

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Clark Canyon


Area = 2,315 mi2

Average Apr-Jul total volume inflow = 0.08 M ac-ft (0.09 M ac-ft Natural)



SWE (in) 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-JunAverage 5.93 8.49 10.56 13.15 12.89 4.72

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Clark Canyon

0.00

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0.3519

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Clark Canyon1 Jan Forecast


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0.35

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Clark Canyon1 FebForecast


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0.35

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Clark Canyon1 Mar Forecast


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0.35

1977

1979

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Clark Canyon1 Apr Forecast


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0.35

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Clark Canyon1 May Forecast


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0.35

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Clark Canyon1 June Forecast


Jan Feb Mar Apr May Jun JulR2 0.54 0.55 0.51 0.60 0.66 0.67 0.72

Std dev error 0.05 0.05 0.05 0.04 0.04 0.04 0.03

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Tiber


Area = 4,724 mi2

Average Apr-Jul total volume inflow = 0.43 M ac-ft

Average Oct-Nov total volume inflow = 0.04 M ac-ft


SWE (in) Jan Feb Mar Apr May JunAverage 8.01 12.13 15.37 18.40 15.52 5.85

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Tiber

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0.9019

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Tiber1 Jan Forecast

Actual inflow Observed

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0.90

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Tiber1 Feb Forecast


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0.90

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Tiber1 Mar Forecast


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0.90

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Tiber1 Apr Forecast


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Tiber1 May Forecast


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Tiber1 June Forecast


Jan Feb Mar Apr May June JulyR2 0.28 0.41 0.46 0.51 0.59 0.66 0.80

Standard Error 0.16 0.14 0.14 0.13 0.12 0.11 0.08

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Yellowtail


Area = 19,693 mi2





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Yellowtail

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Yellowtail1 Jan Forecast


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Yellowtail1 Feb Forecast


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Yellowtail1 Mar Forecast


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Yellowtail1 Apr Forecast


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Yellowtail1 May Forecast


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Yellowtail1 June Forecast


Jan Feb Mar Apr May Jun JulWith Holdouts R2 0.38 0.44 0.36 0.44 0.70 0.86 0.91

Std dev Error 0.55 0.54 0.58 0.53 0.39 0.27 0.22

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Boysen


Area = 7,750 mi2





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Boysen

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0.80

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Boysen1 Jan Forecast


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Boysen1 Feb Forecast

Actual inflow Natural Inflow Observed

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Boysen1 Mar Forecast


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Boysen1 Apr Forecast


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Boysen1 May Forecast


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Boysen1 June Forecast


Jan Feb Mar Apr May Jun JulR2 0.45 0.44 0.43 0.48 0.78 0.91 0.91

Standard error: 0.17 0.17 0.17 0.17 0.14 0.10 0.09

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Glendo


Area = 15,562 mi2

Average Apr-Jul total volume inflow = 0.60 M ac-ft (0.88 M ac-ft Natural)0.14 M ac-ft below Alcova

Average Oct-Nov total volume inflow = 0.13 M ac-ft (0.09 M ac-ft Natural)0.03 M ac-ft below Alcova



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Glendo

0.000.200.400.600.801.001.201.401.601.802.00

Glendo1 Jan Forecast


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Glendo1 Feb Forecast


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Glendo1 Mar Forecast


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Glendo1 Apr Forecast


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Glendo1 May Forecast


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Glendo1 June Forecast


Jan Feb Mar Apr May Jun JunR2 0.43 0.44 0.50 0.60 0.77 0.85 0.88

Standard error: 0.43 0.42 0.40 0.35 0.27 0.22 0.20

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Percent Error

0500

1000150020002500300035004000

Jan Feb Mar apr may jun

Inflo

w (K

AF)

Canyon Ferry

USACE Actual

020406080

100120140


Inflo

w (K

AF)

Clark Canyon

USACE Actual

Canyon FerryUSACE

Jan 39%Feb 43%Mar 44%apr 39%may 28%jun 24%

Clark CanyonJan 30%Feb 27%Mar 36%apr 20%may 18%jun 4%

TiberJan 55%Feb 53%Mar 46%apr 43%may 26%jun 27%

0

200

400

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800

1000


Inflo

w (K

AF)

Tiber

USACE Actual

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Percent Error

*2011 Yellowtail forecast of Actual reservoir inflow for Apr – Jul (USACE and BoR)

USACE Forecast for May-Jul, includes holdouts from Boysen, Buffalo Bill and Bull Lake

0

500

1000

1500

2000

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3000


Inflo

w (K

AF)

Yellowtail - AMJJ Actual Inflow

USACE Actual BoR

0500

100015002000250030003500


Inflo

w (K

AF)

Yellowtail

USACE Actual

0

200

400

600

800

1000

1200


Inflo

w (K

AF)

Boysen

USACE Actual

YellowtailUSACE

Jan 53%Feb 54%Mar 58%apr 53%may 30%jun 2%

BoysenJan 36%Feb 45%Mar 45%apr 45%may 38%jun 2%

BUILDING STRONG®

Percent Error

050

100150200250300350


Inflo

w (K

AF)

Glendo below Alcova

USACE Actual

0

500

1000

1500

2000


Inflo

w (K

AF)

Glendo

USACE Actual

0

500

1000

1500

2000

2500


Inflo

w (K

AF)

Glendo with Holdouts

USACE Actual

GlendoJan 47%Feb 50%Mar 49%apr 42%may 29%jun 23%

Glendo below AlcovaJan 260%Feb 254%Mar 258%apr 242%may 277%jun 312%

Glendo Natural FlowJan 40%Feb 43%Mar 36%apr 23%may 4%jun 12%

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AutomationYellowtail Reservoir Forecasting Tool

To forcast for a given month enter data in the appropriately colored cells Jan Feb Mar Apr May JunCalculated values are shown in bold

Forecasted total volume inflow to reservoir May-Jul (10 6 ac-ft)Jan Feb Mar Apr May June

actual 1.086 1.036 0.978 1.056 0.948 1.169natural (with holdouts) 1.404 1.309 1.225 1.335 1.286 1.561

Total Antecedent Inflow from Oct-Nov

ac-ft 106 ac-ftactual 244780 0.245natural (with holdouts) 244780 0.245

Holdouts

30-Nov 1-Oct Oct-Novac-ft ac-ft ac-ft

Boysen 621834 639219 -17385Buffalo Bill 455551 483785 -28234Bull Lake Reservoirs 69623 65893 3730Total Holdout -0.042 106 ac-ft

Precipitation stationsPrecipitation (in) http://cdo.ncdc.noaa.gov/dlyp/DLYPJan-Oct Nov Dec 2011 Jan Feb Mar Apr May June

Cody 481840 6.21 0.00 0.00 6.21 0.00 0.00 0.07 1.03 3.78Lander Hunt Fld AP 12.97 0.75 0.73 14.45 0.50 1.39 0.28 1.05 0.56Powell Fld Stn 4.34 0.52 0.18 5.04 0.00 0.96 0.12 0.67 3.41Riverton 10.11 0.14 0.60 10.85 0.24 0.75 0.08 0.21 5.29Worland 489785 0.84 0.52 0.25 1.61 0.14 0.12 0.42 0.57 1.31

Average 7.63 0.18 0.64 0.19 0.71 2.87Cumulative Average 0.18 0.82 1.01 1.72 4.59

Average of SWE at stations on first of month (in) Jan Feb Mar Apr May JuneAverage 7.7 10.2 12.2 15.7 20.2 20.5

Col # 0.0 1.0 2.0 3.0 4.0 5.0Blad Mtn. 56 10.1 16.0 19.3 24.0 32.1 41.1Bear Trap Meadow 57 3.3 5.5 6.3 8.8 11.4 7.5Blackwater 58 14.1 17.9 20.8 26.9 36.7 43.1Bone Springs Div 59 7.9 12.9 15.7 20.3 28.2 33.2Burroughs Creek 60 7.9 10.1 12.1 15.8 20.7 20.3

4/1/2011

PeriodMost

Probable% of

Normal1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Apr 1-May 1-Jun

Boysen May-July 524 94% 122% 111% 109% 108% 41%Canyon Ferry (actual) Apr-July 2162 116% 115% 113% 110% 116% 69%Canyon Ferry (natural) (1) Apr-July 2250 115% 115% 113% 110% 116% 69%Clark Canyon Apr-June 115 137% 134% 136% 128% 139% 89%Glendo (actual) Apr-July 966 168% 147% 137% 134% 139% 112%Glendo (natural) (1) Apr-July 1512 179% 147% 137% 134% 139% 112%Alcova to Glendo Apr-July 161 120% 112% 117% 116% 106% 112%Tiber Apr-July 454 108% 98% 105% 118% 123% 86%Yellowtail (actual) May-July 1056 109% 120% 118% 114% 118% 64%Yellowtail (natural) (1) May-July 1335 99% 120% 118% 114% 118% 64%

Reservoir Inflow Forecast (KAF) Basin Snowpack (% Normal) Precipitation (% Normal)

Goals:• Link regression equations, data and

statistics to final forecast sheet• Links to data sources (semi-automated)• Limit data entry and calculation errors• Easily transfer regression coefficients

each year• Easily transfer annual data to regression

analysis workbook

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2011 Issues

Late snowfall in April► Switched from 1 Apr SWE to Max(1 Apr, 1 May)

Real-time precipitation data ► Difficult to automate

Canyon Ferry results► Not capturing complete water balance by the end of the season

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Proposed Improvements to Inflow Forecasting

Daily estimates of forecasted inflow for monitoring► Need to automate regression analysis and data stream

Climate change impacts to regression analysis► Temperature appears to be increasing, Precipitation neither increasing

or decreasing► Changes in climate will reduce the accuracy of regressions over time► Limit data used in analysis to recent years rather than entire period of

record

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0.0E+00

5.0E+09

1.0E+10

1.5E+10

2.0E+10

2.5E+10

3.0E+10

7/10/1987 4/5/1990 12/30/1992 9/26/1995 6/22/1998 3/18/2001 12/13/2003 9/8/2006 6/4/2009

Tota

l bas

in S

WE

(m3)

dateSWE IDW SWE IDW-elev SWE Average SSM/I NOHRSC


Further investigation of better SWE estimation► Test in different basins► Field measurements to better understand distribution of snow

Canyon Ferry

BUILDING STRONG®


Passive Microwave Satellite Observations of SWE in the Great Plains

► Algorithms developed in Great Plains region of Canada.► Shown promising results in Red River of the North Basins► Independent estimate of SWE, available real-time► Long period of record (1987 – present)► Evaluate by comparison to NOHRSC, ground and flight observations,

hydrologic analysis

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Passive Microwave detection of snowmelt and runoff► Affected by presence of wet snow► Research into detection of “ripe” snow and rain-on-snow events► May provide information on timing of melt and flood forecasting

Hydrologic Analysis of Plains snowpack► Correlation between timing and volume to SWE in Plains to discharge► Terrain-state modeling ► Statistical analysis/rank-order

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Thank you

Documents

Omaha Districts Inflow Forecast Regression Analysis