Upper Merced HUC8 18040008
A 3,288 km² sub-basin of the California region in CA. Drought coverage is from the US Drought Monitor (map of 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
59
Moderate
Drought index
96
Abnormally dry
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
100%
of 2 reporting
Median flow
33%
p12 of record
Water assets
1,883
15 springs · 458 wells
USGS gauges (2)
- MERCED R A HAPPY ISLES BRIDGE NR YOSEMITE CA112645003 cfsp11 · below normal
- MERCED R A POHONO BRIDGE NR YOSEMITE CA1126650014 cfsp12 · below normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-19 | 96 | 0 | 2/2 | p12 |
| 2026-10-18 | 96 | 0 | 2/2 | p13 |
| 2026-10-17 | 96 | 0 | 2/2 | p14 |
| 2026-10-16 | 96 | 0 | 2/2 | p13 |
| 2026-10-15 | 96 | 0 | 2/2 | p14 |
| 2026-10-14 | 96 | 0 | 2/2 | p15 |
| 2026-10-13 | 96 | 0 | 2/2 | p13 |
| 2026-10-12 | 96 | 0 | 2/2 | p12 |
| 2026-10-11 | 96 | 0 | 2/2 | p12 |
| 2026-10-10 | 96 | 0 | 2/2 | p12 |
| 2026-10-09 | 96 | 0 | 2/2 | p13 |
| 2026-10-08 | 96 | 0 | 2/2 | p11 |
| 2026-10-07 | 96 | 0 | 2/2 | p10 |
| 2026-10-06 | 96 | 0 | 2/2 | p12 |
Top water assets
- 69Merced Riverriver
- 69Crane Creekriver
- 69Long Meadow Creekriver
- 69Ottoway Creekriver
- 69Triple Peak Forkriver
- 69Illilouette Creekriver
- 69Clark Fork Illilouette Creekriver
- 69Big Creekriver
- 69Crane Creekriver
- 69Moss Creekriver