MOAB — Moab City and Grand County are reckoning with recent studies that suggest their underground water supply might not be as abundant as originally thought. Now the city is working to solidify an estimate and determine what restrictions or changes might be necessary to keep the growing area and thriving tourist destination hydrated. In the early 1970s, a study from U.S. Geological Survey estimated there was 22,000 acre-feet of water entering and leaving the Spanish Valley aquifer system each year. An acre-foot equals approximately 326,000 gallons of water, and Moab city is itself using about 2,300 acre-feet of water per year. There are two main aquifers supplying water to the area: the valley-fill aquifer and the Glen Canyon Group aquifers. The city's culinary water comes entirely from the Glen Canyon Group aquifer, particularly its deeper sections. Douglas Kip Solomon, a University of Utah geologist who helped author both recent reports, told KSL.com that "essentially all" the water recharging the aquifer each year is already being withdrawn for use, about 3,600 acre-feet per year between all entities.