Mermentau HUC8 08080202
A 6,664 km² sub-basin of the Lower Mississippi region in LA. Drought coverage is from the US Drought Monitor (map of 2026-09-01); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
67
Moderate
Drought index
200
Severe
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
0%
of 1 reporting
Median flow
113%
p51 of record
Water assets
1,785
0 springs · 1,455 wells
USGS gauges (4)
- Mermentau River At Mermentau, LA08012150732 cfsp51 · normal
- Byu Queue De Tortue @ Riceville, LA08012300109 cfsno long-term record
- Mermentau River @ Lake Arthur, LA08012400-130 cfsno long-term record
- Bayou Lacassine near Lake Arthur, LA080124702,300 cfsno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 200 | 0 | 0/1 | p51 |
Top water assets
- 65Gum Gullyriver
- 65Middle Bayou Grand Maraisriver
- 65Bayou Queue de Tortueriver
- 65Bayou Queue de Tortueriver
- 65Schooner Bayou Canalriver
- 65Indian Bayouriver
- 65Bayou Lacassine Near Lake Arthur, Lariver
- 65Byu Queue De Tortue @ Riceville, Lariver
- 65Lyons Point Gullyriver
- 65Thornwell Drainage Canalriver