2 USGS Streamgages
Issaquah Creek flows and levels
Issaquah Creek is gauged at 2 USGS streamgages in Washington, each tracked by Rivermatics. It feeds the Sammamish River. Drainage area at the gauges ranges from 18 square miles at Issaquah Creek near Hobart, WA up to 57 at Issaquah Creek near Mouth near Issaquah, WA. The gauged reach falls about 285 feet, from 337 feet down to 52. Rivermatics issues a daily machine-learned 14-day flow outlook for every one of them.
Gauges on this river, upstream to downstream
Ordered by drainage area, which is how far down the river each gauge sits. April and July figures are long-term median daily flows for that month from the USGS record — historical normals, not a forecast and not today's reading.
| Gauge | State | Drainage sq mi | Elevation ft | April p50 cfs | July p50 cfs | Forecast |
|---|---|---|---|---|---|---|
| Issaquah Creek near Hobart, WA | WA | 18 | 337 | 47.6 | 14.4 | 14-day |
| Issaquah Creek near Mouth near Issaquah, WA | WA | 57 | 52 | 136.2 | 35.5 | 14-day |
Typical flow by month at Issaquah Creek near Mouth near Issaquah, WA
The furthest-downstream gauge on this river, so the fullest flow it carries here. Long-term daily discharge percentiles from the USGS record (up to 63 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 91.8 | 195.9 | 528.9 | |
| February | 88.9 | 171.1 | 402.7 | |
| March | 95.2 | 168.3 | 350.2 | |
| April | 79.3 | 136.2 | 250.5 | |
| May | 52.7 | 84.8 | 154.1 | |
| June | 35.2 | 58.5 | 143.5 | |
| July | 23 | 35.5 | 66.6 | |
| August | 17.6 | 25.7 | 45.1 | |
| September | 18.6 | 26.6 | 59 | |
| October | 24.5 | 41 | 110.2 | |
| November | 43.2 | 120.6 | 328.3 | |
| December | 73.8 | 180 | 464.8 |
All values in cubic feet per second (cfs).
Common questions
- When does the Issaquah Creek run highest?
- January, on the long-term record at Issaquah Creek near Mouth near Issaquah, WA — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 195.9 cfs that month, against 25.7 cfs in August, the lowest. Upstream gauges peak on their own schedule; the table on this page gives April and July for each.
- How many gauges are on the Issaquah Creek?
- Rivermatics tracks 2 USGS streamgages on the Issaquah Creek, across Washington. Each has its own page with the site's full flow record and monthly normals. The river may carry other gauges that publish neither daily values nor discharge statistics; those are not tracked here.
- Is there a flow forecast for the Issaquah Creek?
- Yes, at 2 of the 2 gauges. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on each basin's observed flows, weather and snowpack, and issues a daily outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on each gauge's live screen.
- Can I use Issaquah Creek data for flood or safety decisions?
- No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.