In many US aquifers, declining water tables and near-surface contamination are driving groundwater users to construct deeper wells. But a new study reveals that fresh groundwater is less abundant in several key US basins than previously thought, and drilling deeper wells to access fresh groundwater resources is not feasible extensively across the continent. Grant Ferguson and colleagues quantified the depths that aquifer systems transition from fresh to brackish, and where oil and gas activities are widespread in sedimentary basins across the US. Fresh-brackish transitions occur at depths of just a few hundred metres, they found, particularly in eastern US basins. According to the researchers, their findings illustrate that groundwater stores are depleted not only by excessive withdrawals, but due to injection, and potentially contamination, from the oil and gas industry in areas of deep fresh and brackish groundwater.
Find out more in this video abstract Grant Ferguson et al
Video courtesy CC-BY 3.0, Grant Ferguson et al 2018 Environ. Res. Lett. 13 114013 https://doi.org/10.1088/1748-9326/aae6d8
