Note
The Laguna Madre of Texas, together with the Laguna Madre Tamaulipas in northeastern
Mexico, extend nearly continuously for 430 km along the northwestern rim of the Gulf of
Mexico. The lagoon is characteristically a few kilometers wide and at most a few meters
deep. The Texas portion of Laguna Madre is subdivided into northern and southern halves,
separated by approximately 40 km of sand and mud flats which are only rarely inundated.
The dredging of the Gulf Intracoastal Waterway in 1949 reconnected these two sections. At
present, boat and barge traffic moves freely along the length of Laguna Madre, but the
extent to which water is exchanged between the northern and southern portions of the lagoon
is poorly understood.