Grass River at Chase Mills NY
USGS Site No: 04265432 • Grass River • St. Lawrence County, NY
Grass River at Chase Mills NY on the Grass River is currently at 646 cfs (Normal — 37th percentile for this date) . Gage height: 4.87 ft. This station is at or above flood stage.
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 | 262 | |
| 25th | Low threshold | 391 | |
| 50th (Median) | Normal (median) | 909 | Today: 646 cfs |
| 75th | High threshold | 1,880 | |
| 95th | Very High threshold | 3,740 |
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 | 871 | — |
| May 27, 2026 | 1,040 | — |
| May 26, 2026 | 997 | — |
| May 25, 2026 | 700 | — |
| May 24, 2026 | 615 | — |
| May 23, 2026 | 670 | — |
| May 22, 2026 | 784 | — |
| May 21, 2026 | 933 | — |
| May 20, 2026 | 1,080 | — |
| May 19, 2026 | 1,190 | — |
| May 18, 2026 | 1,180 | — |
| May 17, 2026 | 1,390 | — |
| May 16, 2026 | 1,500 | — |
| May 15, 2026 | 1,290 | — |
| Apr 21, 2026 | 2,530 | — |
| Apr 20, 2026 | 3,060 | — |
| Apr 19, 2026 | 3,130 | — |
| Apr 18, 2026 | 3,450 | — |
| Apr 17, 2026 | 3,430 | — |
| Apr 16, 2026 | 3,290 | — |
| Apr 15, 2026 | 2,530 | — |
| Apr 14, 2026 | 1,550 | — |
| Apr 13, 2026 | 1,310 | — |
| Apr 12, 2026 | 1,320 | — |
| Apr 11, 2026 | 1,420 | — |
| Apr 10, 2026 | 1,570 | — |
| Apr 9, 2026 | 1,840 | — |
| Apr 8, 2026 | 2,100 | — |
| Apr 7, 2026 | 2,450 | — |
| Apr 6, 2026 | 2,540 | — |
Station Information
- USGS Site No
- 04265432
- State
- NY
- County
- St. Lawrence County
- Coordinates
- 44.8465, -75.0784
- Drainage Area
- 598 mi²
- Datum (ft)
- 225.6
- HUC Code
- 04150304
Flood Stage Thresholds
- Action Stage
- 7.0 ft
Recent Extremes
- Max discharge
-
6,260 cfsMar 13, 2026
- Min discharge
-
88 cfsSep 22, 2025
Computed from the local daily-values archive.
Nearby Gauges
-
Raquette River at Raymondville NYHigh4.9 mi · 2,230 cfs
-
Plum Bk Near Grantville NYUnknown8.4 mi
-
St. Regis River at Brasher Center NYNormal14.7 mi · 750 cfs
- Unknown
-
Oswegatchie River Near Heuvelton NYNormal22.5 mi · 1,510 cfs