USGS Streamgage 08358400
Rio Grande Floodway at San Marcial, NM
Rio Grande Floodway at San Marcial, NM is USGS streamgage 08358400 in New Mexico, monitoring river discharge in hydrologic subbasin 13020203. It drains a watershed of about 27,700 square miles. Discharge records at this site go back to 1949. Typical flow runs near 78.2 cfs in July and 304.2 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- New Mexico
- Drainage area
- 27,700 sq mi
- Gauge elevation
- 4,457 ft
- Subbasin (HUC-8)
- 13020203
- Coordinates
- 33.67908, -106.997
- USGS site number
- 08358400
- Records begin
- 1949-10-01 (77 years)
Typical flow by month
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 | 0 | 502.5 | 949.9 | |
| February | 0 | 532 | 1,074.7 | |
| March | 0 | 390.5 | 1,311.6 | |
| April | 0 | 304.2 | 2,537.7 | |
| May | 0 | 1,172.3 | 4,181.9 | |
| June | 0 | 530.5 | 4,143.3 | |
| July | 0 | 78.2 | 2,060.9 | |
| August | 0 | 84 | 1,387.9 | |
| September | 0 | 37.8 | 718.7 | |
| October | 0 | 60.9 | 626.8 | |
| November | 0 | 433.9 | 1,233.5 | |
| December | 0 | 538.9 | 1,292.1 |
All values in cubic feet per second (cfs).
Common questions
- When does Rio Grande Floodway at San Marcial, NM normally run highest?
- May, on the long-term record. The median daily flow that month is about 1,172.3 cfs, against 37.8 cfs in September, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Rio Grande Floodway at San Marcial, NM?
- It depends on the month. In January, half of days historically fall near 502.5 cfs, with the middle 80% of days between 0 and 949.9 cfs. The month-by-month table on this page gives the full range.
- How long has Rio Grande Floodway at San Marcial, NM been measured?
- Discharge records at USGS site 08358400 begin in 1949, about 77 years, covering roughly 9,126 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is Rio Grande Floodway at San Marcial, NM?
- The gauge sits at 33.67908, -106.997, in New Mexico, in hydrologic subbasin 13020203, at an elevation of about 4,457 feet, draining roughly 27,700 square miles.
- Can I use Rio Grande Floodway at San Marcial, NM 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.