Applying the METRIC Evapotranspiration Model in Idaho

Transcription

1 Applying the METRIC Evapotranspiration Model in Idaho The First Step, Not the Last Word Anthony Morse and William J. Kramber Idaho Department of Water Resources Boise, Idaho

2 THE FIRST STEP Prototype Applications Demonstration of Concept Existing IDWR Programs

3 APPLICATIONS LIST Modeling: ET for Setting Water Budgets Planning: ET by Land Use Class Hydrology: Aquifer Depletion Water Administration: Monitoring Water Rights Agricultural Water Use

4 MODELING ET for Water Budgets - The Old Way Aquifer Recharge for Each Model Cell recharge = diversion + precipitation - ET Potential ET sw = acres sw * crop percentage * crop coefficient Water Rights Aquifer Depletion Potential ET gw = acres gw * crop percentage * crop coefficient

5 MODELING ET for Water Budgets - Using METRIC For Each Model Cell Water Rights METRIC Output Pixel Mean by Polygon = Polygon Actual ET ET for Recharge = (Mean of Surface Water Polygon) x (Polygon Area) Depletion = (Mean of Ground Water Polygon) x (Polygon Area)

6 PLANNING ET by Land Cover Class Land Use / Land Cover 2000 ET From METRIC 2000 ET by Land Use /Land Cover Polygon How Does Water Use Change as Land Use Changes?

7 PLANNING ET by Land Cover Class Seasonal ET 3/15/2000 to 10/15/2000 Class Name ET in mm Petroleum Tanks 237 Rangeland 242 Unclassified 298 Barren 335 Commercial / Industrial 380 Transportation 420 Idle Agriculture 436 Abandoned Agriculture 459 Junk Yard 467 Feedlot 479 Dairy 524 Other Agriculture 536 Public 548 Sewage 552 New Subdivision 606 Farmstead 609 Rural Residential 657 Urban Residential 684 Canal 731 Irrigated Crops 812 Perennial 820 Recreation 826 Water 924 Wetland 1,025

8 PLANNING ET by Land Cover Class Importance

9 HYDROLOGY Aquifer Depletion

10 HYDROLOGY Aquifer Depletion Present Method Power Meter Records ~5,000 6,000 Wells 6-8 Month Time Lag ~$300,000 Per Year ~$50 Per Well Wells and Water Rights

11 HYDROLOGY Aquifer Depletion Alternative METRIC ~5,000-6,000 Wells 1 Month Time Lag ~$7 Per Well Wells and Water Rights with ET Map

12 Hydrology Aquifer Depletion Accuracy

13 WATER ADMINISTRATION Monitoring Water Rights Compliance Irrigation Without a Water Right Irrigation in Violation of the Conditions of a Right Maximum Rate of Diversion

14 WATER ADMINISTRATION Monitoring Water Rights Compliance Irrigation Without a Water Right

15 WATER ADMINISTRATION Water Rights Compliance Monitoring Irrigation in excess of the conditions of a water right Selected 426 Wells/Fields Used 2 Consecutive Landsat Overpasses (17 Days) Computed 17-Day Cumulative ET (ET 17 ) Used Maximum Diversion Rate for 17 Days (DR 17 ) Compared 17-Day Depth (D 17 ) with ET 17 If ET 17 > D 17, Investigate

16 WATER ADMINISTRATION Water Rights Compliance Monitoring

17 WATER ADMINISTRATION Water Rights Compliance Monitoring ANALYSIS 18 Fields Exceeded Rate Limits 15 of 18 Due to Water Right File Issues 3 Valid Positives Farmers Contacted Within 4 Weeks

18 WATER ADMINISTRATION Agricultural Water Use Actual Not Potential - ET

19 WATER ADMINISTRATION Agricultural Water Use Year Water Use in Acre Feet Irrigated Hectares Mean Water Use in Millimeters Source ,313,505 1,437, Alfalfa (.77) IDWR/METRIC ,176, Census of Agriculture ,367, USGS ,241, Census of Agriculture ,396,707 1,097, (807 Alfalfa) (.61) USGS ,169, Census of Agriculture ,817,991 1,235, (957 Alfalfa) (.70) USGS/IDWR ,146, Census of Agriculture

20 WATER ADMINISTRATION Agricultural Water Use Irrigated Acres Water Use Year 2000 (METRIC) Results are Higher Generalizing Effects of LU/LC (Area) Different Methods (ET) Different Start and End Dates (ET)

21 DIFFERENT DATES Blaney-Criddle (1990 Estimate) Start: Emergence (April-June) End: Harvest (September-October) METRIC Start: March 1, 2000 End October 31, 2000

22 DIFFERENT DATES April 8, 2000 October 16, 2000

23 SUMMARY ET from an Energy Balance Model Demonstrated Applications Modeling: ET for Setting Water Budgets Planning: ET by Land Use Class Hydrology: Aquifer Depletion Water Administration: Monitoring Water Rights Agricultural Water Use

24 INFORMATION

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