Lake Meredith, which supplies water for domestic use to all major Texas cities on the Southern High Plains, exceeds State of Texas limits for chloride and sulfate content.

Cores and supporting petrophysical data from 20 wells in McAllen Ranch field were analyzed. This Vicksburg field lies in northern Hidalgo County near the south end of the Texas Gulf Coastal Plain on the downthrown block of a major growth fault that merges with a glide plane dipping 5 degrees to the east beneath the field. The analyses provided a base for interpreting depositional environments.We grouped cored strata into four facies: (1) prodelta shales, (2) distal delta-front sandstones and shales, (3) proximal delta-front sandstones, and (4) distributary-channel sandstones.