1. Beta Release of Delta Evapotranspiration of Applied Water (DETAW v2.0)
Lan Liang
Bay-Delta Office
Department of Water Resources
Delta Modeling User Group
June 20th, 2018

2. Acknowledgements DWR Bay-Delta Office:
Tariq Kadir, Bob Suits, Nicky Sandhu, Tara Smith,
Jon Shu, Wenli Yin, Yu Zhou
DWR Division of Statewide Integrated Water Management
Morteza Orang
UC Davis
Richard L. Snyder

3. Model Development History
Delta consumptive use models in use in Bay-Delta Office CU
DICU
DETAW v1.0
DETAW v2.0

4. DETAW V2.0 vs DETAW V1.0 Improvements in DETAW v2.0
Platform from C++ to Python
Save code running time
Output format from Excel to DSS files
Calibration of crop coefficients based on remote sensing data
Seepage rates

5. Principle behind DETAW V2.0
Island root zone water balance on each of 15 crop categories and 168 sub-areas:
Crop ET = effective irrigation+ effective seepage
+ effective rainfall + soil moisture change

6. Characteristics of DETAW V2.0 Beta Release
Estimates the actual ET and crop needed applied water, effective precipitation and effective seepage.
Etc Calibrated and validated with SEBAL 2007 and 2009 data
Daily time step
168 sub-areas and 15 crop categories
Simulation periods: WY1922 – 2016
Two land use sets: historical simulation and projected simulation

7. Performance of DETAW v2.0 Historical Simulation
2007
2009
TAF
Calibration
SEBAL: TAF
DETAW v2.0: TAF
Difference: %
Validation
SEBAL: TAF
DETAW v2.0: TAF
Difference: %

8. All seven methods are within 11% of the average ET. 2015
Delta crop ET comparison of seven models initiated by Delta Watermaster through UCDavis
Agricultural lands only. About 30% of Delta Service Area is not included.
All seven methods are within 11% of the average ET.
2015
2016
From the draft report “Estimation of Crop Evapotranspiration in the Sacramento-San Joaquin Delta”

9. DETAW v2.0 Beta Release Package
Linkage to the DETAW V2.0 model package
Contact
Min Yu,

10. DETAW v2.0 Beta Release Package
Technical reports User’s manual
Two sets of land use data
Inputs and code

11. File Structure of DETAW v2.0 Historical Simulation
Inputs
Outputs
Input 1: Main control DETAW_para.inp
Input 2: Precipitation
mm_pcp.csv
Daily outputs:
DETAW_day_**.dss
Input 3: Daily temperature at Lodi LODI_PT.csv
Run DETAW model: DETAW.py
Input 4: Crop information
critical.csv and noncritical.csv
Input 5: Land use of 168 subareas in subfolder \Historical
Monthly output:
DETAW_month.dss
Input 6: Precipitation and ETo correction factors, Percentage.csv

12. Input 1: Main Control

13. Input 2: Daily Precipitation
No data at Brentwood, Galt, and Rio Vista now. Their precipitations are estimated by the correlations with those at other stations.

14. Input 3: Daily Temperature
Data source of precipitation and temperature:
Statewide Integrated Pest Management, University of California

15. Input 4: Crop Information
Critical set and noncritical set for different water years
Irrigation season for each of 15 crop categories
Soil depth
Rooting depth
Crop coefficients for each phase during the growth season

16. Input 4: Crop Information

17. Input 5: Land Use
Two sets of land use: 168 files of historical simulation and 168 files of projected simulation
Each file has the annual acreages of 15 crop categories of one island.
Unit: Hectare

18. Input 6: Precipitation and ETo Correction Factors
Theissen Polygon
The correction factors were determined by the errors between CIMIS ETo and the estimated ETo at Lodi.

19. Run DETAW v2.0
Install Python
Install Command Prompt (optional)

20. Outputs
Daily Outputs
DETAW_day_##.dss: daily crop ET and other terms from 1922 through 2016 for 15 crop categories and 10 or 8 islands
17 DSS files for 168 islands
Monthly outputs
DETAW_month.dss: monthly crop ET and other terms from 1922 through 2016 for 15 crop categories and 168 islands

21. Conclusion
It is Beta release. Any suggestions or questions are welcome.
The documents can provide answers for most technical questions.
The Delta crop ET has been calibrated and validated. However, the local crop ET is still under investigation.