Western States Remote Sensing of ET Workshop Boise, 12 October 2011

1. Consumptive use from energy balance (METRIC) and conventional estimates for basin management, water accounting, and interstate agreements Tim Martin1, Phil Burkhalter1, Rick Allen2 (1Riverside Technology inc., 2University of Idaho) Western States Remote Sensing of ET Workshop Boise, 12 October 2011 METRICTM

2. Irrigation and Water Management Applications Mapping Evapotranspiration with high Resolution and Internalized Calibration (METRIC) - Satellite-based energy balance, developed by Rick Allen, U. of Idaho - Supporting Riverside’s applications projects over past five years • Wyoming and Nebraska: North Platte Decree Committee, 2010 • Irrigation consumptive use monitoring for interstate water compact • Colorado: Water Conservation Board (NASA ROSES grant, 2007-11) • Comparison of South Platte DSS consumptive use model (StateCU) results with METRIC base • New Mexico: USBR (NASA ROSES grant, 2010-11) • Application of METRIC as input to water planning model (Upper Rio Grande Water Operations Model) • Morocco: The World Bank, 2008-10 • Irrigation system monitoring and evaluation for $250M system rehabilitation project; water balance model estimating groundwater abstraction • Wyoming: State Engineers Office, 2011-16 • “Assessing Consumptive Water Use Via Remotely Sensed Data”

3. Conventional and Satellite Remote Sensing ET Methods • Conventional Method ET: • Weather data points, extrapolated • Crop coefficients, assume “well-watered”, single for each crop type • Crop maps or cropping patterns required • Satellite Imagery for Estimating ET: • Energy balance at each “pixel” • Limited or no ground observation required • Valid for natural vegetation • Can assess variability due to: • Crop constraints (e.g. salinity, disease, pests) • Agronomic practices • Water shortage • Evaporation from bare soil

4. ET derived from METRIC and conventional StateCU in South Platte R. Basin • Overview • 268 ditch service areas • 784,449 acres irrigated • Irrigation method • 67% flood irrigated • 33% sprinkler irrigated • Irrigation source • 56% surface water only • 18% groundwater only • 26% both sw & gw • Major crops • corn • alfalfa • grass • small grains • sugar beets, beans, etc.

5. StateCU Model comparison with METRIC ET • State of Colorado’s Consumptive Use Model • Calculates irrigation water requirement (IWR), monthly time step, by ditch service area (268) • Parameters include: crop type, reference ET, irrigation efficiency, surface water supply, supplemental groundwater availability, effective precipitation • Reference ET is calculated using a modified Blaney-Criddle • METRIC ET Estimation • From multidateLandsat imagery, computed daily ET images • StateCU crop calendars used for start and end dates • Extensive GIS data used from CDSS (Colorado Decision Support Systems) including: ditch service area, irrigated parcels, crop type, irrigation type, and irrigation water source.

6. ET,F Results ETrF estimated for (top) Apr, May, Jun, Jul; (bottom): Aug, Sept, Oct, Nov

7. Sample ETrF Results Daily ET expressed as ETrF for 05/12, 07/07, and 09/25 for the area north of Wiggins, CO

8. METRIC Comparison with SPDSS StateCU Model Analysis Spreadsheet Tool:

9. METRIC Comparison with SPDSS StateCU Model General Analysis Results (268 Service Areas) Scenario 4 Results – Volume

10. METRIC Comparison with SPDSS StateCU Model Alfalfa Detailed Analysis Results (Crop Type) – Volume Plots: Corn Dry Beans Grass Pasture

11. METRIC Comparison with SPDSS StateCU Model Orchard Detailed Analysis Results (Crop Type) – Volume Plots: Small Grains Sod Farm Sugar Beets

12. METRIC Comparison with SPDSS StateCU Model General Analysis Results (Geographic Region) – METRIC Map:

13. METRIC Comparison with SPDSS StateCU Model General Analysis Results (Geographic Region) – StateCU Map:

14. METRIC Comparison with SPDSS StateCU Model Samples of METRIC results after post-processing: Example of daily METRIC ET (in Acre-Ft) by parcel for an area near Fort Morgan, CO for June 24, 2001

15. METRIC Comparison with SPDSS StateCU Model Samples of METRIC results after post-processing: Sample of final monthly METRIC ET totals for June for a ‘groundwater only’ area showing crop type

16. North Platte Decree Committee (NPDC) • U.S. Supreme Court decree in 1945 • Interstate river compact among Colorado-Wyoming- Nebraska allocating water use of N. Platte • Various claims and judgments: 1953, 1986, 1993, 1995, 2001 • Specifies Wyoming’s maximum irrigated acres and consumptive use • State of Wyoming’s irrigation monitoring program • Reports annual irrigation and CU • Based on ag statistics = questions of accuracy and reliability • Based on field observation = labor-intensive • Instructed by Court to investigate alternative methods

17. North Platte Monthly ET(Example Area)

18. Saratoga Reservoir North Platte Irrigated Parcels Assessment • Irrigated parcels delineated by Wyoming staff superimposed on METRIC Seasonal ET • METRIC provides ET by pixel; can be used as alternative or complement to field mapping

19. Morocco: Water Management Surface water measurement and distribution varies by sector. Groundwater use is mostly unregulated and not measured.

20. Dec 06 Nov 06 Oct 06 Sep 06 Feb 07 Jan 07 Apr 07 Mar 07 Aug 07 May 07 Jun 07 Jul 07 ETa by Month 2006–2007 for Sample Irrigation Sectors (Tadla ORMVA)

21. Annual ET for Tadla ORMVA

22. Monthly Water Balance for Example Irrigation Sector (RD S1.3)

23. Summary • METRIC-derived ET applications demonstrate value for: • Assessing actual ET in complex irrigation schemes • Spatial and • Temporal variability • Unbiased ET estimates • Pre- (and post-) assessment of irrigation system rehabilitation • Monitoring for river compacts and treaties • Water rights conflict resolution • Surface and ground water modeling • Water management decision support • Reliable, spatially distributed ET data used with • GIS data and analysis allow very detailed • analysis and understanding of ET at parcel level

24. Thank You! Tim.Martin@riverside.com