In many semiarid and arid regions around the world, groundwater drawn from basin-fill aquifers sustains local agriculture and large cities. Such aquifers are typically replenished by high-elevation precipitation and snowmelt along encircling mountain fronts via several pathways. These pathways include infiltration from streams, diffuse subsurface flow from the mountains to the basin, and focused subsurface flow along features like faults. Distinguishing among these various means of mountain front recharge is necessary to effectively manage aquifers' limited water supplies, but it can be challenging because the waters moving through different paths can be difficult to sample and often have similar chemical fingerprints.
source https://phys.org/news/2021-02-parsing-routes-aquifer-recharge-mountain.html
