Stanislaus and Tuolumne Rivers Groundwater Basin Association GSA

San Joaquin Valley - Modesto

What changed at each monthly refresh. Bold lines are notable changes. Subscribe to the RSS feed to get each update in a feed reader.

Readings through Sep 2026: first edition

• Kriged average 98 ft below ground in Sep 2026, 2.1 ft deeper than a year earlier. No readings in Jul–Sep 2026; the newest is from Mar 2026.
• 13 of 62 RMS wells read in the last 12 months are below their MT.
• Plan's undesirable-result rule not met in the latest readings.
• 7 wells at a record low (deepest since 2005) in the last 12 months.
• NOAA-outlook forecast for Sep 2027: 97 ft below ground.
• Under the outlook the plan rule is met by Sep 2027 (chance about 60%).

Forecasts use the NOAA outlook (CPC's Oct 2026 issue: water year 2027 at 122% of normal precipitation).