St. Marys River at Decatur, IN
USGS Site No: 04181500 • St. Marys River • Adams County, IN
St. Marys River at Decatur, IN on the St. Marys River is currently at 332 cfs (High — 83th percentile for this date) . Gage height: 5.29 ft.
Reading from
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 | 17 | |
| 25th | Low threshold | 22 | |
| 50th (Median) | Normal (median) | 47 | |
| 75th | High threshold | 118 | |
| 95th | Very High threshold | 671 | Today: 332 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 | 494 | — |
| May 27, 2026 | 650 | — |
| May 26, 2026 | 679 | — |
| May 25, 2026 | 721 | — |
| May 24, 2026 | 899 | — |
| May 23, 2026 | 952 | — |
| May 22, 2026 | 587 | — |
| May 21, 2026 | 550 | — |
| May 20, 2026 | 493 | — |
| May 19, 2026 | 196 | — |
| May 18, 2026 | 149 | — |
| May 17, 2026 | 162 | — |
| May 16, 2026 | 188 | — |
| May 15, 2026 | 219 | — |
| Apr 21, 2026 | 314 | — |
| Apr 20, 2026 | 512 | — |
| Apr 19, 2026 | 867 | — |
| Apr 18, 2026 | 860 | — |
| Apr 17, 2026 | 824 | — |
| Apr 16, 2026 | 1,030 | — |
| Apr 15, 2026 | 753 | — |
| Apr 14, 2026 | 164 | — |
| Apr 13, 2026 | 182 | — |
| Apr 12, 2026 | 220 | — |
| Apr 11, 2026 | 293 | — |
| Apr 10, 2026 | 453 | — |
| Apr 9, 2026 | 757 | — |
| Apr 8, 2026 | 1,170 | — |
| Apr 7, 2026 | 1,800 | — |
| Apr 6, 2026 | 2,670 | — |
Station Information
- USGS Site No
- 04181500
- State
- IN
- County
- Adams County
- Coordinates
- 40.8481, -84.9377
- Drainage Area
- 621 mi²
- Datum (ft)
- 760.1
- HUC Code
- 04100004
Flood Stage Thresholds
- Action Stage
- 13.0 ft
- Flood Stage
- 17.0 ft
- Moderate Flood
- 20.0 ft
- Major Flood
- 24.0 ft
Currently 11.71 ft below flood stage.
Recent Extremes
- Max discharge
-
3,690 cfsMay 7, 2025
- Min discharge
-
13 cfsJan 31, 2026
- Days at flood stage
- 0
Computed from the local daily-values archive.
Nearby Gauges
-
St. Marys River at Pleasant Mills, INVery High6.9 mi · 342 cfs
-
Blue Creek near Pleasant Mills, INVery High9.2 mi · 10 cfs
-
St Marys River at Walcot Street at Willshire OHVery High10.4 mi · 372 cfs
-
St. Marys River Near Fort Wayne, INHigh13.3 mi · 409 cfs
-
Wabash River at Bluffton, INVery High14.2 mi · 610 cfs