Blanco Rv at San Marcos, TX
USGS Site No: 08171350 • Blanco River • Hays County, TX
Blanco Rv at San Marcos, TX on the Blanco River is currently at 5 cfs (Normal — 26th percentile for this date) . Gage height: 8.12 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 | 0 | |
| 25th | Low threshold | 0 | |
| 50th (Median) | Normal (median) | 116 | Today: 5 cfs |
| 75th | High threshold | 229 | |
| 95th | Very High threshold | 0 |
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 | 13 | — |
| May 27, 2026 | 7 | — |
| May 26, 2026 | 5 | — |
| May 25, 2026 | 1 | — |
| May 24, 2026 | 1 | — |
| May 22, 2026 | 1 | — |
| May 21, 2026 | 1 | — |
| May 20, 2026 | 2 | — |
| May 19, 2026 | 1 | — |
| May 18, 2026 | 1 | — |
| May 17, 2026 | 1 | — |
| May 16, 2026 | 1 | — |
| May 15, 2026 | 1 | — |
| Apr 20, 2026 | 0 | — |
| Apr 19, 2026 | 0 | — |
| Apr 18, 2026 | 0 | — |
| Apr 17, 2026 | 0 | — |
| Apr 16, 2026 | 0 | — |
| Apr 15, 2026 | 0 | — |
| Apr 14, 2026 | 0 | — |
| Apr 13, 2026 | 0 | — |
| Apr 12, 2026 | 0 | — |
| Apr 11, 2026 | 0 | — |
| Apr 10, 2026 | 0 | — |
| Apr 9, 2026 | 0 | — |
| Apr 8, 2026 | 0 | — |
| Apr 7, 2026 | 0 | — |
| Apr 6, 2026 | 0 | — |
| Apr 5, 2026 | 0 | — |
| Apr 4, 2026 | 0 | — |
Station Information
- USGS Site No
- 08171350
- State
- TX
- County
- Hays County
- Coordinates
- 29.8795, -97.9108
- Drainage Area
- 436 mi²
- Datum (ft)
- 543.0
- HUC Code
- 12100203
Flood Stage Thresholds
- Action Stage
- 13.0 ft
- Flood Stage
- 18.0 ft
- Moderate Flood
- 24.0 ft
- Major Flood
- 30.0 ft
Currently 9.88 ft below flood stage.
Recent Extremes
- Max discharge
-
225 cfsJun 14, 2025
- Min discharge
-
0 cfsApr 17, 2026
- Days at flood stage
- 0
Computed from the local daily-values archive.
Nearby Gauges
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Onion Ck near Driftwood, TXLow15.2 mi · 0 cfs
-
Guadalupe Rv at Sattler, TXNormal16.2 mi · 93 cfs
-
Guadalupe Rv above Comal Rv at New Braunfels, TXNormal16.5 mi · 199 cfs
-
Little Bear Ck at Stoneledge Quarry near Manchaca,txUnknown17.0 mi · 0 cfs
-
Guadalupe Rv at New Braunfels, TXUnknown17.2 mi · 0 cfs