Abstract

Water chemistry, tritium data, precipitation-discharge relations, geology, topography, and dye tracing were used to determine recharge areas, ground-water residence times, factors influencing ground-water flow, and aquifer characteristics for five springs that discharge from Paleozoic limestones and dolostones along the margin of Mantua Valley, northern Utah.

Temperature of Mantua Valley spring water ranged between 6.0 and 15.0 degrees Celsius. Spring-water temperature indicates that depth of circulation of ground water could be as shallow as 80 feet (25 meters) to as much as 1,150 feet (350 meters). Dissolved-solids concentration in water from the springs ranged from 176 to 268 milligrams per liter. Average total hardness of spring water ranged from 157 to 211 milligrams per liter. Water from all of the springs is a calcium-magnesium-bicarbonate type that generally is undersaturated with respect to calcite and dolomite. The molar calcium/magnesium ratio in spring water ranged from 1.21 to 1.88, and indicates that ground water flows through impure dolostones or a mixed limestone and dolostone terrane.

Discharge from carbonate springs in Mantua Valley ranges from about 10 to 4,300 gallons per minute (0.6 to 271 liters per second). Seasonal variations in chemical parameters and discharge indicate that the aquifers supplying water to most of these springs are predominantly diffuse-flow systems that have been locally enhanced by bedrock dissolution. Estimated recharge area for the springs ranges from 2.7 to 7 square miles (7 to 18 square kilometers).

On the basis of tritium age dating, the mean residence time of ground water discharging from Olsens-West Hallings and Maple Springs was determined to be from 3 to 9, and from 4 to 13 years, respectively. Dye tracing from point sources 2.65 miles (4.26 kilometers) southeast of Maple Spring, however, indicates a substantially faster component of flow during snowmelt runoff, with a travel time of about 5 days, or an average ground-water velocity of about 2,700 feet per day (823 meters per day).