Calibration for Historical Crop ET Estimates –A Process · XXX COAG xlsXXX COAG.xls -- QC dataQC data

EVAPOTRANSPIRATIONWORKSHOPEVAPOTRANSPIRATION WORKSHOP

Calibration for Historical

Crop ET Estimates – A Process

Ivan A Walter P EIvan A. Walter, P.E.

Ivan’s Engineering, Inc.

3/12/2010 1Ivan A. Walter, P.E.

Kc ETstzd vs SCS BCKc ETstzd vs SCS BCKc ETstzd vs SCS BCKc ETstzd vs SCS BC

Kc ET is more accurate than SCS BC Kc ETstzd is more accurate than SCS BC– Kc -- Generate from measurement at known sites

K T f bl– Kc -- Transferrable– ETstzd – ET professional & researchers have

t daccepted– SCS BC – Crop Coefficients derived where???

SCS BC R i l l lib i– SCS BC – Requires local calibration


Why Isn’t Kc ET dUsedWhy Isn’t Kc ET dUsedWhy Isn t Kc ETstzd UsedWhy Isn t Kc ETstzd Used

A t “Wh t?”Answers to “Why not?”– SCS BC is well accepted in Colo.SCS BC is well accepted in Colo.

Water Court. – Do not have the data for ETstzd

Do not have the Kc’s– Do not have the Kc s


What is Desirable ResultWhat is Desirable ResultWhat is Desirable ResultWhat is Desirable Result

J t b f ETJust some number for ETcAccurate daily Temp, Rs, U, & RhAccurate daily Temp, Rs, U, & RhAccurate daily ETrs & ETos

Accurate monthly ETrs & ETos

E l fil & P f l iExcel files & Programs for analysis


Criteria (ASCE Task Committee)Criteria (ASCE Task Committee)Criteria (ASCE Task Committee)Criteria (ASCE Task Committee)

UnderstandableUnderstandableDefensible Simplification without loss of accuracyB d & T bl t E i t lBased on & Traceable to Experimental

Data


Rocky Ford ETrs

10

12

ETrs ETrs Est

8

6

2

4

0Apr May Jun Jul Aug Sep

3/12/2010 Ivan A. Walter, P.E. 6

Rocky Ford: Est as % of Actual

105%

110%

ETrs Est /: ETrs ETos Est / ETos

100%

95%

85%

90%

80%

85%

May Jun Jul Aug Sep


May Jun Jul Aug Sep

0.6

Fort Morgan -- 2005 Daily Data

0.5

ETrs

ETrs Est

0.4

0.3

inch

es

0.2

0.1


01-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct

Raw Data >>>>>> ETcRaw Data >>>>>> ETcRaw Data >>>>>> ETcRaw Data >>>>>> ETc

Download data fromWeb site Download data from Web site

QC the data – Select good data

Calc ETrs, ETos, and ETHrgv Calibration Calc’s with good data Calibration Calc’s with good data

COEFHgrv x ETHrgv = ETrsHgrv Hrgv rs

COEF1Hgrv x ETHrgv = ETos


Begin Hereg

Standardized Reference ET Equation:

)(273

)(408.0 2 eeuT

CGR as

nn

)1(273

2uCT

ETd

ref


Begin Here w/ Data from Webg


Calculate & Analyze & Comparey p

)()(4080 2 eeuC

GR n

Standardized Reference ET Equation:

)1(

)(273

)(408.0

2

2

uC

eeuT

GRET

d

asn

ref

1985 Hargreaves Equation:

ameano RTTTET )8.17()(0023.0 5.0minmax

1985 Hargreaves Equation:


ameano )()( minmax

Final ProductFinal ProductFinal ProductFinal Product

St d di d R f ET l Standardized Reference ET values– Short Crop: ETos– Tall Crop: ETrs– Daily values


Step 1: XXX COAG.xlsStep 1: XXX COAG.xlsStep 1: XXX COAG.xlsStep 1: XXX COAG.xls

Download data from COAGMet site Download data from COAGMet site

QC the data

– Identify the Good Data

Fix small gaps & errors– Fix small gaps & errors

– Throw out everything else


Step 2: ColCrbt2.exe -- ApplicationStep 2: ColCrbt2.exe -- ApplicationStep 2: ColCrbt2.exe ApplicationStep 2: ColCrbt2.exe Application

Input data from XXX COAG xls Input data from XXX COAG.xls– Text file XXXEtrData.prn

Calculates Reference ET (daily)– ETrsETrs– ASCE PM Etr, 1982 Kimberly Penman ETr

– ETosETos– ASCE PM ETo, Hargreaves ETo


Step 3: Colcrbt2.exe -- ResultsStep 3: Colcrbt2.exe -- ResultsStep 3: Colcrbt2.exe ResultsStep 3: Colcrbt2.exe Results

Linear Regression Analysis (daily) Linear Regression Analysis (daily)

Zero intercept

Monthly Ratio: ETrs to ETHgrvMonthly Ratio ET to ETMonthly Ratio: ETos to ETHgrvMonthly Ratio: ETrs to ETosrs os

Regression Coef & SEE


Step 3 Results: Ratio ET : ETHStep 3 Results: Ratio ET : ETHStep 3 Results: Ratio ETrs : ETHrgvStep 3 Results: Ratio ETrs : ETHrgv

MAY JUN JUL AUG SEPMAY JUN JUL AUG SEPFort Morgan(Tdpt Adjusted) 1995 ‐ 2006 1.40 1.36 1.27 1.25 1.37Fort Collins 03 1999 ‐ 2006 1.48 1.41 1.38 1.38 1.56Center 1996 ‐ 2006 1.54 1.38 1.15 1.18 1.47Avondale 1994 ‐ 2008 1.30 1.33 1.22 1.16 1.22Rocky Ford 1994 ‐2008 1.32 1.36 1.22 1.17 1.17Yuma 1996 ‐ 2006 1.58 1.54 1.34 1.28 1.47Fruita 1999 2006 1.34 1.28 1.15 1.13 1.21ll k

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Yellow Jacket 1992 ‐ 2008 1.31 1.29 1.22 1.24 1.36

Results @ Center: Ratio ET : ETHResults @ Center: Ratio ET : ETHResults @ Center: Ratio ETrs : ETHrgvResults @ Center: Ratio ETrs : ETHrgv

MAY JUN JUL AUG SEPAll 1 54 1 38 1 15 1 18 1 47All 1.54 1.38 1.15 1.18 1.471996 1.68 1.25 1.06 1.14 1.471997 1.31 1.32 1.16 1.06 1.251998 1.62 1.56 1.08 1.15 1.481999 1.56 1.43 1.09 1.12 1.382000 1 43 1 30 1 11 1 17 1 572000 1.43 1.30 1.11 1.17 1.572001 1.45 1.35 1.07 1.15 1.522002 1.56 1.36 1.15 1.23 1.342003 1.50 1.38 1.21 1.17 1.482004 1.61 1.38 1.23 1.37 1.562005 1.54 1.44 1.24 1.26 1.57

3/12/2010 Ivan A. Walter, P.E. 18

2005 1.54 1.44 1.24 1.26 1.572006 1.57 1.43 1.17 1.15 1.47

Step 3 Results: Ratio ET : ETHStep 3 Results: Ratio ET : ETHStep 3 Results: Ratio ETos : ETHrgvStep 3 Results: Ratio ETos : ETHrgv

MAY JUN JUL AUG SEPMAY JUN JUL AUG SEPFort Morgan(Tdpt Adjusted) 1995 ‐ 2006 1.02 1.01 0.96 0.96 1.00Fort Collins 03 1999 ‐ 2006 1.07 1.03 1.03 1.03 1.10Center 1996 ‐ 2006 1.15 1.06 0.93 0.94 1.09Avondale 1994 ‐ 2008 1.03 1.01 0.94 0.93 0.99Rocky Ford 1994 ‐2008 1.04 1.04 0.94 0.94 0.95Yuma 1996 ‐ 2006 1.14 1.13 1.03 0.99 1.07Fruita 1999 2006 1.00 0.97 0.90 0.88 0.91ll k

3/12/2010 Ivan A. Walter, P.E. 19

Yellow Jacket 1992 ‐ 2008 1.01 1.01 0.98 0.99 1.05

Step 4: ETRETOH 2.exeStep 4: ETRETOH 2.exeStep 4: ETRETOH 2.exeStep 4: ETRETOH 2.exe

Calculate ET & ET using ET Calculate ETrs & ETos using ETHgrv Input File

– DataT&P.prn from XXX COAG.xls Latitude, Tmax, Tmin, Tavg

– COEFHRGV.datMonthly Coefficient all Station (15 max.)


Step 4: COEFHGRV.datStep 4: COEFHGRV.datStep 4: COEFHGRV.datStep 4: COEFHGRV.dat


Step 4: ETRETOH 2.exeStep 4: ETRETOH 2.exeStep 4: ETRETOH 2.exeStep 4: ETRETOH 2.exe

Calculation of ET & ET using 1985 Calculation of ETrs & ETos using 1985 Hargreaves

ETrs = COEF x ETHgrv (Daily)

ET = COEF1 x ET (Daily) ETos = COEF1 x ETHgrv (Daily)

RTTTET )817()(00230 5.0 ameano RTTTET )8.17()(0023.0 5.0minmax


Step 4: Final ResultsStep 4: Final ResultsStep 4: Final ResultsStep 4: Final Results

Year DOY Month Day ETrs ETos Precip Year, DOY, Month, Day, ETrs,ETos, Precip.


9Ft Morgan ETrs

7

8ETrs ETrs Est

5

6

4

5

2

3

0

1

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8Center ETrs

7ETrs ETrs Est

5

6

3

4

2

3

0

1

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12Yuma2 ETrs

10ETrs ETrs Est

8

6

2

4

0

2

3/12/2010 Ivan A. Walter, P.E. 26

Apr May Jun Jul Aug Sep

12

Rocky Ford ETrs

10

12

ETrs ETrs Est

8

6

4

0

2

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12Avondale ETrs

10

12

ETrs ETrs Est

8

6

2

4

0

2

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12Fruita ETrs

10ETrs ETrs Est

8

6

2

4

0

2

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10Yellow Jacket ETrs

8

9ETrs ETrs Est

6

7

4

5

2

3

0

1

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CoAgMet Stations Years

8 - 11

12 - 14

PTV01 0YUM01 8

HYK02 18HEB01 0.3

COW01 0.4

GLY04 1.5

ILF01 1.9

STG01 3.7

WLT01 4.4

WFD01 5.1

BRG01 7.4

WGG01 7.6

PAI01 8.2

WGG02 8.3

HXT01 12.7

YUM02 13.6WRY01 13.6FTM01 14.7

AKR02 17 5

KSY01 17.6

FTC03 17.6

LCN01 17.8ALT01 17.8

FTC01 17.9

0 - 4

5 - 7

15 - 18

IDL01 18

BRL03 1.7

HRT01 2.7

STN01 3.7

EAC01 9.4

KRK01 13.6

BRL02 17.4FRT02 17 5

AKR02 17.5

BRL01 17.6

FTL01 17.8

FRT01

PAN01 0

ORM01 4

SCM01 1.4

CDG01 3.8

HOT01 11.6DLT01 14.7

GJC01 15.6

OTH01 17.4

BRL02 17.4FRT02 17.5

YJK01 18

PBL01 1.8 LAM02 2.9LAM04 4.6HLY02 4.6LMS01 4.8LJT01 4.8

FWL01 4.8

CTR02 6.2

RFD02 6.5LAM03 7.4 HLY01 8.2

LAM01 13.4

CTR01 16.2

VLD01 16.4

DVC01 17.1

RFD01 17.5AVN01 17.5

CTZ01 18

STT01 1.8LJR01 4.1

YUC01 7.3

SAN01 9.4

HNE01 9.8TWC01 11.5

BLA01 11.6

3/12/2010 Ivan A. Walter, P.E. 31

Process -- Historical ETref EstimatesProcess -- Historical ETref EstimatesProcess Historical ETref EstimatesProcess Historical ETref Estimates

CoAgMet Data CoAgMet Data

XXX COAG.xls ‐‐ QC for Good data

Colcrbt2.exe ‐‐ Cal’c Monthly Hgrv FactorsFactors

ETRETOH 2.exe ‐ Calculate ETrs & ETos


Meadow Grass ETMeadow Grass ET

Review of Methods Recommendation for Calculation ETc

3/12/2010 Ivan A. Walter, P.E. 33

Reported ProceduresReported ProceduresReported ProceduresReported Procedures

SCS BC Past re Grass SCS –BC Pasture Grass– 10% / 1,000 m. change in elevation

ASCE Man al 70 does not recommend– ASCE Manual 70 does not recommend

Pochop Method -- ASAE 1984Li i d Alf lf (9%) & T f (6%)– Limited to Alfalfa (9%) & Turf (6%)

– Adjusted kt --- thus not true SCS BCAdjust from elevation Coefficient derived– Adjust from elevation Coefficient derived

– Wyoming


Reported ProceduresReported ProceduresReported ProceduresReported Procedures

Den er Water Board BC “k” coefDenver Water Board, BC “k” coef.– South Park, Elev. 8,900 ft msl– Standard BC not modified BC– Local calibration– ET calculated as:

Lysimeter water use + Precipitation (100%)

– ETirr wtr = ETc - Precipitation


Recommend Transferrable KcRecommend Transferrable KcRecommend Transferrable Kc Recommend Transferrable Kc

Smith’s G nnison basin Smith’s Gunnison basin – Hargreaves Monthly Coefficients– Letter Describing included in Materials

Maly & Walter – Kc’s Meadow Grass– Memo Describing process included in Materials


Hargreaves Kc’s for Meadow GrassHargreaves Kc’s for Meadow GrassHargreaves Kc s for Meadow GrassHargreaves Kc s for Meadow Grass

M ltiple Sites 5 ears of dataMultiple Sites -- 5 years of dataMay = 1.16 June = 1.28 J l 1 04 July = 1.04August = 0.86 September = 0.88


Meadow Grass Kc ‐‐ Derived using Calibrated Hargreaves

3/12/2010 Ivan A. Walter, P.E. 38

Software & Documents ProvidedSoftware & Documents ProvidedSoftware & Documents ProvidedSoftware & Documents Provided

XXX COAG xls QC data XXX COAG.xls -- QC data Colcrbt2.exe -- Calc’ Monthly Coef. ETRETOH 2.exe -- Calc’ ETrs & ETos

Example Input and Output filesp p p Memo: Coefficients for Meadow Grass Smith Letter: Hargreaves Kc M Grass Smith Letter: Hargreaves Kc M.Grass Daily Ra calculation Application


CoAgMet Stations Years

8 - 11

12 - 14

PTV01 0YUM01 8

HYK02 18HEB01 0.3

COW01 0.4

GLY04 1.5

ILF01 1.9

STG01 3.7

WLT01 4.4

WFD01 5.1

BRG01 7.4

WGG01 7.6

PAI01 8.2

WGG02 8.3

HXT01 12.7

YUM02 13.6WRY01 13.6FTM01 14.7

KSY01 17.6

FTC03 17.6

LCN01 17.8ALT01 17.8

FTC01 17.9

0 - 4

5 - 7

15 - 18

YUM01 8

IDL01 18

BRL03 1.7

HRT01 2.7

STN01 3.7

WFD01 5.1

EAC01 9.4

KRK01 13.6

AKR02 17.5

BRL01 17.6

FTL01 17.8

FRT01

PAN01 0

ORM01 4

SCM01 1.4

CDG01 3.8

HOT01 11.6DLT01 14.7

GJC01 15.6

OTH01 17.4

BRL02 17.4FRT02 17.5

PBL01 1.8 LAM02 2.9LAM04 4.6HLY02 4.6LMS01 4.8LJT01 4.8

FWL01 4.8

CTR02 6.2

RFD02 6.5LAM03 7.4 HLY01 8.2

LAM01 13.4

CTR01 16.2

VLD01 16.4

DVC01 17.1

RFD01 17.5AVN01 17.5

YJK01 18

CTZ01 18

STT01 1.8LJR01 4.1

YUC01 7.3

SAN01 9.4

HNE01 9.8TWC01 11.5

BLA01 11.6

3/12/2010 Ivan A. Walter, P.E. 40