Big Rock C near Valyermo CA
USGS Site No: 10263500 • Los Angeles County, CA
Big Rock C near Valyermo CA is currently at 61 cfs (High — 90th percentile for this date) . Gage height: 2.38 ft.
Reading from
Historical Percentile Comparison
Today's discharge compared to the long-term record for June 11 at this station. Percentile rank shows what fraction of historical years had lower flow on this date.
| Percentile | Label | CFS Threshold | Today's Flow |
|---|---|---|---|
| 10th | Very Low threshold | 3 | |
| 25th | Low threshold | 5 | |
| 50th (Median) | Normal (median) | 10 | |
| 75th | High threshold | 24 | |
| 95th | Very High threshold | 74 | Today: 61 cfs |
30-Day Hydrograph
Recent discharge plotted against the historical 10th–95th percentile envelope for the same calendar days. Source: USGS daily values + long-term statistics.
30-Day Flow History
| Date | Discharge (CFS) | Gage Ht (ft) |
|---|---|---|
| May 28, 2026 | 65 | — |
| May 27, 2026 | 65 | — |
| May 26, 2026 | 63 | — |
| May 25, 2026 | 60 | — |
| May 24, 2026 | 66 | — |
| May 23, 2026 | 75 | — |
| May 22, 2026 | 76 | — |
| May 21, 2026 | 59 | — |
| May 20, 2026 | 49 | — |
| May 19, 2026 | 49 | — |
| May 18, 2026 | 49 | — |
| May 17, 2026 | 49 | — |
| May 16, 2026 | 49 | — |
| May 15, 2026 | 48 | — |
| Apr 20, 2026 | 29 | — |
| Apr 19, 2026 | 30 | — |
| Apr 18, 2026 | 32 | — |
| Apr 17, 2026 | 32 | — |
| Apr 16, 2026 | 35 | — |
| Apr 15, 2026 | 39 | — |
| Apr 14, 2026 | 41 | — |
| Apr 13, 2026 | 43 | — |
| Apr 12, 2026 | 44 | — |
| Apr 11, 2026 | 39 | — |
| Apr 10, 2026 | 39 | — |
| Apr 9, 2026 | 40 | — |
| Apr 8, 2026 | 40 | — |
| Apr 7, 2026 | 41 | — |
| Apr 6, 2026 | 41 | — |
| Apr 5, 2026 | 41 | — |
Station Information
- USGS Site No
- 10263500
- State
- CA
- County
- Los Angeles County
- Coordinates
- 34.4208, -117.8395
- Drainage Area
- 23 mi²
- Datum (ft)
- 4,035.7
- HUC Code
- 18090206
Recent Extremes
- Max discharge
-
1,680 cfsDec 24, 2025
- Min discharge
-
2 cfsOct 13, 2025
Computed from the local daily-values archive.
Nearby Gauges
-
Cucamonga C near Upland CANormal20.8 mi · 6 cfs
-
Cajon C below Lone Pine C near Keenbrook CAVery High23.9 mi · 16 cfs
-
Lytle C near Fontana CAHigh26.1 mi · 44 cfs
-
Fontana Water CO Surface Div near Fontana CAVery High26.9 mi · 24 cfs
- Unknown