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

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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

3/12/2010 2Ivan A. Walter, P.E.

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

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

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

3/12/2010 4Ivan A. Walter, P.E.

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

3/12/2010 5Ivan A. Walter, P.E.

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

3/12/2010 Ivan A. Walter, P.E. 7

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

3/12/2010 Ivan A. Walter, P.E. 8

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

3/12/2010 9Ivan A. Walter, P.E.

Begin Hereg

Standardized Reference ET Equation:

)(273

)(408.0 2 eeuT

CGR as

nn

)1(273

2uCT

ETd

ref

3/12/2010 10Ivan A. Walter, P.E.

Begin Here w/ Data from Webg

3/12/2010 11Ivan A. Walter, P.E.

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:

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

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

3/12/2010 13Ivan A. Walter, P.E.

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

3/12/2010 14Ivan A. Walter, P.E.

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

3/12/2010 15Ivan A. Walter, P.E.

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

3/12/2010 16Ivan A. Walter, P.E.

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

3/12/2010 Ivan A. Walter, P.E. 17

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.)

3/12/2010 20Ivan A. Walter, P.E.

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

3/12/2010 21Ivan A. Walter, P.E.

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

3/12/2010 22Ivan A. Walter, P.E.

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. 

3/12/2010 23Ivan A. Walter, P.E.

9Ft Morgan ETrs

7

8ETrs ETrs Est

5

6

4

5

2

3

0

1

3/12/2010 Ivan A. Walter, P.E. 24

0Apr May Jun Jul Aug Sep

8Center ETrs

7ETrs ETrs Est

5

6

3

4

2

3

0

1

3/12/2010 Ivan A. Walter, P.E. 25

0Apr May Jun Jul Aug Sep

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

3/12/2010 Ivan A. Walter, P.E. 27

0Apr May Jun Jul Aug Sep

12Avondale ETrs

10

12

ETrs ETrs Est

8

6

2

4

0

2

3/12/2010 Ivan A. Walter, P.E. 28

Apr May Jun Jul Aug Sep

12Fruita ETrs

10ETrs ETrs Est

8

6

2

4

0

2

3/12/2010 Ivan A. Walter, P.E. 29

Apr May Jun Jul Aug Sep

10Yellow Jacket ETrs

8

9ETrs ETrs Est

6

7

4

5

2

3

0

1

3/12/2010 Ivan A. Walter, P.E. 30

Apr May Jun Jul Aug Sep

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

3/12/2010 32Ivan A. Walter, P.E.

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

3/12/2010 34Ivan A. Walter, P.E.

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

3/12/2010 35Ivan A. Walter, P.E.

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

3/12/2010 36Ivan A. Walter, P.E.

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

3/12/2010 37Ivan A. Walter, P.E.

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

3/12/2010 39Ivan A. Walter, P.E.

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