The geochemical sources and processes controlling the water quality of groundwater in the Mud Lake area were determined by investigating the geology, hydrology, land use, and groundwater geochemistry in the Mud Lake area, proposing sources for solutes, and testing the proposed sources through geochemical modeling with PHREEQC.Modeling indicated that sources of water to the eastern Snake River Plain aquifer were groundwater from the Beaverhead Mountains and the Camas Creek drainage basin; surface water from Medicine Lodge and Camas Creeks, Mud Lake, and irrigation water; and upward flow of geothermal water from beneath the aquifer.Large amounts of chloride, sodium, sulfate, and calcium are added to groundwater from irrigation water infiltrating through lake bed sediments containing evaporite deposits and the resultant dissolution of gypsum, halite, sylvite, and bischofite.), although proposed sources include solution of continuous fallout of Na Cl from the atmosphere, evaporation, infiltration of irrigation water, leaching of Na Cl from the soil horizon, solution of evaporite deposits, inputs of HCl and H, inflow of thermal water, flushing of grain boundaries and pores from marine sediments, dissolution of fluid inclusion Na Cl from basalt, and water–rock interaction with rhyolite and andesite (Robertson et al.Groundwater in the Mud Lake area resides in the eastern Snake River Plain (ESRP) aquifer, a sole-source fractured-basalt aquifer of significant economic value to the State of Idaho. The geochemical sources and processes controlling the water quality of groundwater of the Mud Lake area were determined by investigating the geology, hydrology, land use, and groundwater geochemistry in the Mud Lake area, proposing sources for solutes, and testing the proposed sources through geochemical modeling with PHREEQC (Parkhurst and Appelo ) are linear features on the ESRP that contain centers of basalt eruptions.Thermal water was calcium sulfate (site 57), calcium bicarbonate (site 58), and sodium bicarbonate (site 100)..Old water was estimated for 2 sites in the mountains and 4 sites on the ESRP; young water was estimated for 3 sites in the mountains, 3 sites on the ESRP, and Camas Creek; and a mixture of young and old water was estimated for 3 sites in the mountains and 4 sites on the ESRP (Table ) or from sites with unusual chemistry (i.e., anoxic water) located in volcanic vent corridors (sites 25 and 29).The depth to water in wells (excluding the 3,159-m deep test well INEL-1, site 100; Fig.) on the ESRP ranged from about 3–137 m with a mean depth of about 53 m; the maximum depth of well open intervals was 71 m with a mean maximum depth of 33 m.
Solutes in groundwater are derived from recharge water, anthropogenic inputs, and chemical reactions.
Consequently, this study investigates the geochemistry of the shallow (upper 71 m) ESRP aquifer.
Site number, date sampled, measurements of the stable isotopes (2 sigma uncertainty) of hydrogen, oxygen, and carbon and the radiogenic isotope tritium (1 sigma uncertainty), and approximate age of water The reliability of water-quality data was evaluated with the replicate samples and calculation of the charge balance (CB) of water samples.
Groundwater from wells (sites 3, 32, and 35) and cold springs (sites 55, 56, and 59) in the mountains had temperatures ranging from 5.8 to 12.8 °C, p H ranging from 6.9 to 7.8, Sp C ranging from 258 to 523 µS/cm at 25 °C, were anoxic to slightly undersaturated with oxygen (1.1–94.4 % saturation), and had moderate-to-large carbon dioxide (CO ranged from −3.25 to −1.72.
Cation and anion concentrations (in mg/L) ranged from 15 to 109 for calcium, 4.6 to 33.0 for magnesium, 9.0 to 85.0 for sodium, 2.0 to 7.2 for potassium, 131 to 457 for bicarbonate, 5.6 to 121 for chloride, 5.3 to 91.3 for sulfate, 0.15 to 1.01 for fluoride, and 0.03 mg/L as N were measured in water from a few sites (sites 18, 25, 27, and 29), and large lithium concentrations were measured at sites 25 (71 μg/L) and 29 (47 μg/L).