San Marcos Spgs at San Marcos, TX
USGS Site No: 08170000 • Hays County, TX
Current reading not available.
Nearby gauges with live readings
This gauge isn't reporting right now. These nearby USGS gauges are currently active:
- Onion Ck near Driftwood, TX 14.1 mi@if($nearby->currentReading) · 0 cfs@endif
- Guadalupe Rv at Sattler, TX 14.9 mi@if($nearby->currentReading) · 93 cfs@endif
- Guadalupe Rv above Comal Rv at New Braunfels, TX 16.0 mi@if($nearby->currentReading) · 199 cfs@endif
- Little Bear Ck at Stoneledge Quarry near Manchaca,tx 16.5 mi@if($nearby->currentReading) · 0 cfs@endif
- Guadalupe Rv at New Braunfels, TX 16.8 mi@if($nearby->currentReading) · 0 cfs@endif
Historical Percentile Comparison
Today's discharge compared to the long-term record for October 28 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 | 91 | |
| 25th | Low threshold | 116 | |
| 50th (Median) | Normal (median) | 149 | |
| 75th | High threshold | 196 | |
| 95th | Very High threshold | 287 |
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.
10th–95th historical
Day-of-year median
Recent discharge
30-Day Flow History
| Date | Discharge (CFS) | Gage Ht (ft) |
|---|---|---|
| May 28, 2026 | 87 | — |
| May 27, 2026 | 88 | — |
| May 26, 2026 | 88 | — |
| May 25, 2026 | 86 | — |
| May 24, 2026 | 85 | — |
| May 23, 2026 | 85 | — |
| May 22, 2026 | 85 | — |
| May 21, 2026 | 85 | — |
| May 20, 2026 | 85 | — |
| May 19, 2026 | 85 | — |
| May 18, 2026 | 85 | — |
| May 17, 2026 | 85 | — |
| May 16, 2026 | 86 | — |
| May 15, 2026 | 85 | — |
| Apr 20, 2026 | 84 | — |
| Apr 19, 2026 | 78 | — |
| Apr 18, 2026 | 76 | — |
| Apr 17, 2026 | 75 | — |
| Apr 16, 2026 | 74 | — |
| Apr 15, 2026 | 75 | — |
| Apr 14, 2026 | 76 | — |
| Apr 13, 2026 | 77 | — |
| Apr 12, 2026 | 76 | — |
| Apr 11, 2026 | 75 | — |
| Apr 10, 2026 | 74 | — |
| Apr 9, 2026 | 74 | — |
| Apr 8, 2026 | 74 | — |
| Apr 7, 2026 | 74 | — |
| Apr 6, 2026 | 73 | — |
| Apr 5, 2026 | 73 | — |
Station Information
- USGS Site No
- 08170000
- State
- TX
- County
- Hays County
- Coordinates
- 29.8891, -97.9342
- Datum (ft)
- 557.7
- HUC Code
- 12100203
Recent Extremes
- Max discharge
-
108 cfsJul 15, 2025
- Min discharge
-
72 cfsMar 28, 2026
Computed from the local daily-values archive.
Nearby Gauges
-
Onion Ck near Driftwood, TXNormal14.1 mi · 0 cfs
-
Guadalupe Rv at Sattler, TXNormal14.9 mi · 93 cfs
-
Guadalupe Rv above Comal Rv at New Braunfels, TXNormal16.0 mi · 199 cfs
-
Little Bear Ck at Stoneledge Quarry near Manchaca,txUnknown16.5 mi · 0 cfs
-
Guadalupe Rv at New Braunfels, TXUnknown16.8 mi · 0 cfs