Reservoir · California · United States · CDEC
UNION VALLEY
76.7% full
Capacity
251.63 hm³
Volume stored
193 hm³
Vs month average
93% of normal
Coordinates
38.864°N, 120.438°W
Last updated
2026-10-14
Current fill
76.7%vs 7 days ago
-2.9%losing
vs 1 year ago
-16.9%year-over-year
7-day trend
↓falling
Drought context
Storage vs October average
93%of normal
76.7% full on 2026-10-14, against an average of 82.6% for October across 6 years of readings (-5.9 points).
Data source: CDEC — California Dept of Water Resources — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-10-14.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 38.864, -120.438 · Open in Google Maps
About UNION VALLEY
As of October 14, 2026, UNION VALLEY is filled to 76.7% of its total capacity, holding roughly 193 hm³ of water out of a maximum 252 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has fallen by 2.9 percentage points, and it is 16.9 points below its level on the same date a year earlier.
Across the readings we hold for UNION VALLEY — 1824 data points between October 16, 2021 and October 14, 2026 — the level has ranged from a low of 44.2% (October 20, 2021) to a high of 105.0% (March 6, 2022). On average the reservoir is fullest around May and at its lowest around November.
It is operated by CDEC primarily for multiple purposes. It lies within the California basin at 38.864°N, 120.438°W.
Key facts
- Current fill level
- 76.7%
- Water stored
- 193 hm³
- Total capacity
- 252 hm³
- 7-day change
- ▼ 2.9 pts
- Year-on-year
- ▼ 16.9 pts
- Primary use
- Multipurpose
- River basin
- California
- Operator
- CDEC
- Coordinates
- 38.864°N, 120.438°W
- Last updated
- October 14, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 14 Oct 2026 | 76.7% | 193 |
| 13 Oct 2026 | 77.0% | 194 |
| 12 Oct 2026 | 77.3% | 195 |
| 11 Oct 2026 | 77.6% | 195 |
| 10 Oct 2026 | 78.0% | 196 |
| 9 Oct 2026 | 78.4% | 197 |
| 8 Oct 2026 | 79.0% | 199 |
| 7 Oct 2026 | 79.6% | 200 |
| 6 Oct 2026 | 80.3% | 202 |
| 5 Oct 2026 | 81.1% | 204 |
| 4 Oct 2026 | 81.8% | 206 |
| 3 Oct 2026 | 82.6% | 208 |