The study looked at the groundwater system in Moab, Utah, which is important for the city's water supply. They found that the groundwater recharge is not enough to sustain future water demands. By analyzing different chemical tracers, they discovered that the groundwater is mainly recharged by local streams, not from the main aquifer as previously thought. Their calculations show that the amount of water entering the deeper aquifer is about the same as the water being pumped out.