Oil Production, Agriculture, and Groundwater Quality in the Southeastern Gulf Coast Aquifer, Texas

Associations between groundwater quality and land usewere evaluated in the southeastern Gulf Coast Aquifer,Texas. Data from 19 234 oil/gas wells and 256 water wellswere mapped with a geographic information system (GIS) andstatistically analyzed. Water wells near oil/gas wells hadsignificantly higher levels of chloride, bromide, and totaldissolved solids (TDS). Bromide-chloride ratios were alsohigher at water wells near oil/gas wells. Shallower waterwells had significantly higher chloride, bromide, TDS, andnitrate concentrations. Nitrate concentrations were higherbeneath cropland compared to other land uses. Results ofthis study suggest that oil/gas production and agriculturehave impacted water quality in the Gulf Coast Aquifer.     

Low‐Capacity Well Pairs for Treating Contaminated Groundwater in Homogeneous and Heterogeneous Aquifers

Groundwater remediation alternatives were simulated for homogeneous and heterogeneous aquifers with a numerical mass transport model. Low‐energy alternatives involved an injection–extraction well pair positioned along a downgradient linear transect. This transect was located 5 m from the contaminant plume and oriented perpendicular to the regional hydraulic gradient. Through numerous trials, for one homogeneous and three heterogeneous settings, the model identified an optimal spacing and minimum pumping rate for a well pair: (1) centered on the downgradient tip of the plume (best centered), and (2) anywhere along the downgradient transect (best overall). Results suggest that low‐energy well pairs are an effective means for containing and removing some contaminant plumes, and best‐performing configurations are generally not centered on the downgradient tip of the initial contaminant plume. ©2015 Wiley Periodicals, Inc.