Root Zone Water Budget • Independently estimate:

• Precipitation (PR) • Evapotranspiration (ET) • Runoff (RO) • Percolation (DP) • Change in Storage (dS)

• Solve for Applied Water (AW) AW = ET + RO + DP + dS – PR

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Butte Valley Water Budget Development

NDVI for Crop Coefficient (Kc)

Reference ET (ETo) Daily ET (ETo x Kc)

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Oregon State University PRISM

AW – Applied Water DP – Deep Percolation

PR – Precipitation RO – Runoff

ET – Evapotranspiration

From Precipitation: NRCS Curve Number (CN) method From Irrigation: Estimated as % of Applied Water

Estimated Daily Based On Soil Type, Precipitation, and Applied Water

Estimated Daily, Generally Negligible on Annual Basis

Closure Term

Butte Valley Water Budget Development

Water Budget Analysis Area

• Majority of Butte Valley Watershed • Watershed area: 388,000 acres • Groundwater basin area: 80,000 acres

• Divided into over 14,000 Polygons • Alfalfa • Grain and Hay • Pastures • Misc. Truck • Strawberries • Idle • Wetlands • Native Vegetation • Developed Areas • Water Bodies

• Land Use Classification • DWR (2000, 2010, 2014)

3 Butte Valley Water Budget Development

Water Budget Analysis Area

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• Entire Butte Valley Watershed

• Watershed area: 388,000 acres

• Groundwater basin area:

80,000 acres

• Divided into over 14,000 Polygons

• Land Use Classification

• DWR (2000, 2010, 2014)

Butte Valley Water Budget Development

• Annual Inflows = Annual Outflows

• Minimal change in root zone storage

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Water Budget Summary by Land Use

Grain and Hay (2010, 2014) Pasture (2009 – 2018)

Alfalfa (2010, 2014)

Butte Valley Water Budget Development

• Annual Inflows = Annual Outflows

• Minimal change in root zone storage

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Water Budget Summary by Land Use

Wetlands (2009 – 2018) Native (2009 – 2018)

Butte Valley Water Budget Development

Strawberries (2010, 2014)

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Groundwater Basin Land Surface Water Budget (2009 – 2018)

Butte Valley Water Budget Development

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Groundwater Basin Land Surface Annual Water Budget (2009 – 2018)

*Note: Positive numbers represent inflows and negative numbers represent outflows.

WET YEAR DRY YEAR

Butte Valley Water Budget Development

Butte Valley Water Budget Development 9

Land Surface Water Budget: Precipitation

• Wet Year: 2011

Butte Valley Water Budget Development 10

Land Surface Water Budget: Precipitation

• Dry Year: 2014

Butte Valley Water Budget Development 11

Land Surface Water Budget: Precipitation

• Wet Year – Dry Year

Butte Valley Water Budget Development 12

Land Surface Water Budget:

Evapotranspiration • Wet Year: 2011

Butte Valley Water Budget Development 13

Land Surface Water Budget:

Evapotranspiration • Dry Year: 2014

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Land Surface Water Budget:

Evapotranspiration • Wet Year – Dry Year

Butte Valley Water Budget Development 15

Land Surface Water Budget:

Applied Water • Wet Year: 2011

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Land Surface Water Budget:

Applied Water • Dry Year: 2014

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Land Surface Water Budget:

Applied Water • Wet Year – Dry Year

Next Steps

• Refine Based on Local Knowledge • Integrate with IDC Model • Integrate with Groundwater/Surface Water

Model • Others?

18 Butte Valley Water Budget Development