Groundwater Sustainability Plan

The Groundwater Sustainability Plan is a basin wide plan that lays out a path for sustainable management of a groundwater basin over a 20-year period, and focuses on avoiding undesirable results. It was designed to keep groundwater resources at or above 2015 levels.
The plan was designed through the lens of 6 different sustainability indicators and safeguards against:

1. Lowering of Groundwater Levels
2. Reduction in Groundwater Storage
3. Seawater Intrusion
4. Degradation of water quality
5. Land subsidence
6. Surface water depletion

Napa County's GSP

Statewide GSP’s

Annual Groundwater Report

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How the Plan Works

​What happens when we reach an undesirable result?

• Planned Management Actions are triggered when minimum thresholds are exceeded
• Can be voluntary reduction of usage 10%
• Increase best management practices outreach
• Mandatory pumping reductions
• Other tools to avoid undesirable results

What are some tools I can use to achieve 10% groundwater pumping reduction this season?

• Consider tilling to reduce cumulative water usage
• Manage Canopies appropriately (hedge often)
• Reduce overall leaf area early
• Switch to surface water if available
• Stretch irrigation intervals where possible
• Foliar nutrition to reduce stress
• Use shade cloth, other ET reducing tools like surround
• Monitor vine stress levels 
  • Pressure chamber
  • Sap flow sensors
  • Real time ET stations 

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What are some long term ways to reduce groundwater pumping?

• Rootstock choice when replanting
• Row orientation
  • Can reduce cumulative water usage by up to 30% changing to a “softer” row orientation that shades itself during high temperatures
• Ground Preparation and Ripping depth
  • More access to deeper soils buffers vines in heat events
• Double Poly, Misting systems, improvements to drip irrigation
• Develop onsite storage