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Mermentau River at Mermentau

Critical Stages
4' - Action
4' - Flood
6' - Moderate
8' - Major

Latest Observation

Updated: 1:15 PM CST 12/15/25

Status: No Flooding

Stage: 2.41 ft

Flow: 0.43 kcfs

Forecast

TimeStage (ft)Flow (kcfs)
6 PM 12/15 2.5 0.5
12 AM 12/16 2.6 0.707
6 AM 12/16 2.6 0.707
12 PM 12/16 2.6 0.707
6 PM 12/16 2.6 0.707
12 AM 12/17 2.6 0.707
6 AM 12/17 2.6 0.707
12 PM 12/17 2.6 0.707
6 PM 12/17 2.6 0.707
12 AM 12/18 2.6 0.707
6 AM 12/18 2.6 0.707
12 PM 12/18 2.6 0.707
6 PM 12/18 2.6 0.707
12 AM 12/19 2.6 0.707
6 AM 12/19 2.6 0.707
12 PM 12/19 2.6 0.707
6 PM 12/19 2.5 0.5
12 AM 12/20 2.5 0.5
6 AM 12/20 2.5 0.5
TimeStage (ft)Flow (kcfs)
1:15 PM 12/15 2.41 0.43
1:00 PM 12/15 2.4 0.423
12:45 PM 12/15 2.39 0.416
12:30 PM 12/15 2.38 0.409
12:15 PM 12/15 2.39 0.416
12:00 PM 12/15 2.37 0.402
11:45 AM 12/15 2.36 0.395
11:30 AM 12/15 2.36 0.395
11:15 AM 12/15 2.35 0.388
11:00 AM 12/15 2.35 0.388
10:45 AM 12/15 2.35 0.388
10:30 AM 12/15 2.35 0.388
10:15 AM 12/15 2.35 0.388
10:00 AM 12/15 2.35 0.388
9:45 AM 12/15 2.34 0.381
9:30 AM 12/15 2.34 0.381
9:15 AM 12/15 2.34 0.381
9:00 AM 12/15 2.34 0.381
8:45 AM 12/15 2.35 0.388
8:30 AM 12/15 2.34 0.381
8:15 AM 12/15 2.35 0.388
8:00 AM 12/15 2.35 0.388
7:45 AM 12/15 2.35 0.388
7:30 AM 12/15 2.36 0.395
7:15 AM 12/15 2.35 0.388
7:00 AM 12/15 2.34 0.381
6:45 AM 12/15 2.36 0.395
6:30 AM 12/15 2.35 0.388
6:15 AM 12/15 2.35 0.388
6:00 AM 12/15 2.35 0.388
Hydrograph for Mermentau River at Mermentau
16' - Between 16 and 17 ft, flood waters reach the gauge over the mermentau river.
15.1' - Between 15.1 and 16.0 ft, flood waters reach the base of the southern pacific railroad bridge east of mermentau across an unnamed tributary.
14.3' - The river is at its flood of record. Widespread major to catastrophic flooding will occur.
13.4' - The river is near its 100 year flood level. Most of the community of mermentau is inundated with flood waters.
13.3' - Water reaches the roadway of the of U.S. 90 bridge east of Mermentau.
11.9' - Flood waters reach the roadway on the Field Road bridge east of mermentau.
10' - Widespread flooding over a large area from Interstate 10 to Lake Arthur with numerous homes and roads flooded. The community of Morse will be inundated with water. Much of Estherwood will be inundated due to backwater flooding from Bayou Plaquemine. Areas around Gueydan will be inundated with water due to backwater flooding from Bayou Que de Tortue. Communities of Klondike and Lowery will experience flooding as well.
9.5' - Widespread major flooding will occur with residential flooding in and around mermentau to the lake arthur area. Numerous roads are inundated across a large area including u.S. 90, la 3166, la 1126, and la 92.
9' - Some residential flooding in and around mermentau will occur. U.S. 90 west of mermentau is closed. Operations at the shipyards are affected. Roads in the mermentau cove area are flooded and impassable. Some residences are subject to flooding along the river near lake arthur.
8.5' - Some residential flooding in mermentau will occur. Operations at leevac shipyard can be affected. U.S. Highway 90 west of mermentau is flooded and subject to being closed.
7.5' - Water is on the roadway of the Field Road bridge in the southeast part of mermentau.
6.2' - The water reaches the roadway of the 13th Street bridge in the southern portion of mermentau.
6' - Flooding of the shipyard begins. Portions of castex landing, la 3166, become flooded and impassable.
5.5' - A few recreational camps and residences are subject to flooding.
4' - Minor lowland flooding near the river will occur.
DateStage (ft)
Aug 7, 1940 14.5
Aug 18, 2016 10.68
Jan 15, 2013 10.56
Dec 10, 1972 9.47
Apr 25, 1977 9.05
May 18, 2004 8.96
Jun 2, 1941 8.66
May 6, 2017 8.61
May 20, 1980 8.56
Apr 18, 1967 8.54
Jul 10, 1946 8.27
Jul 6, 1989 8.13
Apr 18, 1969 8.02
Apr 21, 1973 7.74
May 22, 2021 7.48
Jan 28, 1974 7.46
Jun 30, 1957 7.43
Feb 17, 1966 6.94
Sep 16, 1998 6.91
Nov 6, 2002 6.89

Data provided by the National Weather Service.