USGS Streamgage 14220500
Lewis River at Ariel, WA
Lewis River at Ariel, WA is USGS streamgage 14220500 in Washington, monitoring river discharge in hydrologic subbasin 17080002. It sits on the Lewis River, alongside 1 other gauge Rivermatics tracks on the same river. It drains a watershed of about 731 square miles. Discharge records at this site go back to 1909. Typical flow runs near 1,776.1 cfs in July and 5,024.7 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.
View live conditions & forecast →
Gauge details
- State
- Washington
- Drainage area
- 731 sq mi
- Subbasin (HUC-8)
- 17080002
- Coordinates
- 45.95174, -122.56397
- USGS site number
- 14220500
- Records begin
- 1909-07-01 (117 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Lewis River at Ariel, WA. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.
| Date | Low p10 | Expected p50 | High p90 | Range |
|---|---|---|---|---|
| 1,255 | 1,297 | 1,331 | ||
| 1,260 | 1,310 | 1,355 | ||
| 1,218 | 1,324 | 1,405 | ||
| 1,192 | 1,316 | 1,431 | ||
| 1,191 | 1,316 | 1,458 | ||
| 1,203 | 1,308 | 1,536 | ||
| 1,194 | 1,304 | 1,560 | ||
| 1,197 | 1,302 | 1,643 | ||
| 1,205 | 1,302 | 1,793 | ||
| 1,163 | 1,295 | 1,652 | ||
| 1,140 | 1,293 | 1,623 | ||
| 1,152 | 1,292 | 1,680 | ||
| 1,160 | 1,295 | 1,717 | ||
| 1,170 | 1,297 | 1,932 |
All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 117 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 | 2,898.7 | 7,392.3 | 12,029 | |
| February | 2,688.3 | 6,524.1 | 11,900 | |
| March | 2,561.3 | 5,681.6 | 10,461.6 | |
| April | 2,425.3 | 5,024.7 | 8,687.7 | |
| May | 2,210.3 | 4,540.6 | 7,996.5 | |
| June | 1,601.3 | 3,057.3 | 6,582 | |
| July | 884.2 | 1,776.1 | 3,392.9 | |
| August | 782.8 | 1,228.7 | 2,020 | |
| September | 817.3 | 1,400.3 | 3,422.7 | |
| October | 1,046.7 | 2,409 | 5,660.6 | |
| November | 2,176.7 | 5,318.7 | 11,113.3 | |
| December | 2,640.3 | 7,095.8 | 12,371 |
All values in cubic feet per second (cfs).
Common questions
- When does Lewis River at Ariel, WA normally run highest?
- January, on the long-term record. The median daily flow that month is about 7,392.3 cfs, against 1,228.7 cfs in August, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Lewis River at Ariel, WA?
- It depends on the month. In January, half of days historically fall near 7,392.3 cfs, with the middle 80% of days between 2,898.7 and 12,029 cfs. The month-by-month table on this page gives the full range.
- How long has Lewis River at Ariel, WA been measured?
- Discharge records at USGS site 14220500 begin in 1909, about 117 years, covering roughly 9,200 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for Lewis River at Ariel, WA?
- Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow 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 the live gauge screen. Open live conditions to see the current outlook.
- Where is Lewis River at Ariel, WA?
- The gauge sits at 45.95174, -122.56397, in Washington, in hydrologic subbasin 17080002, draining roughly 731 square miles.
- Can I use Lewis River at Ariel, WA 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.
Upstream and downstream on the Lewis River
Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Lewis River in full.
- Lewis River above Muddy River near Cougar, WA 227 sq mi
- Lewis River at Ariel, WA this page