Groundwater flow and its effect on salt dissolution in Gypsum Canyon watershed, Paradox Basin, southeast Utah, USA

Reitman, Nadine G.; Ge, Shemin; Mueller, Karl

Groundwater flow and its effect on salt dissolution in Gypsum Canyon watershed, Paradox Basin, southeast Utah, USA | Ecoulements d’eau souterraine et leur effet sur la dissolution du sel dans le bassin gypsifère du Canyon, Bassin du Paradox, Sud Est de l’Utah, Etats Unis d’Amérique Flujo de agua subterránea y su efecto en la disolución de sales en la cuenca de Gypsum Canyon, Paradox Basin, sudeste de Utah, EEUU 美国犹他州东南部Paradox盆地Gypsum Canyon流域的地下水流及其对盐类溶解的影响 O fluxo de água subterrânea e o seu efeito sobre a dissolução de sais na sub-bacia hidrográfica de Gypsum Canyon, Bacia de Paradox, no sudeste de Utah, EUA

2014

Reitman, Nadine G. | Ge, Shemin | Mueller, Karl

Groundwater flow is an important control on subsurface evaporite (salt) dissolution. Salt dissolution can drive faulting and associated subsidence on the land surface and increase salinity in groundwater. This study aims to understand the groundwater flow system of Gypsum Canyon watershed in the Paradox Basin, Utah, USA, and whether or not groundwater-driven dissolution affects surface deformation. The work characterizes the groundwater flow and solute transport systems of the watershed using a three-dimensional (3D) finite element flow and transport model, SUTRA. Spring samples were analyzed for stable isotopes of water and total dissolved solids. Spring water and hydraulic conductivity data provide constraints for model parameters. Model results indicate that regional groundwater flow is to the northwest towards the Colorado River, and shallow flow systems are influenced by topography. The low permeability obtained from laboratory tests is inconsistent with field observed discharges, supporting the notion that fracture permeability plays a significant role in controlling groundwater flow. Model output implies that groundwater-driven dissolution is small on average, and cannot account for volume changes in the evaporite deposits that could cause surface deformation, but it is speculated that dissolution may be highly localized and/or weaken evaporite deposits, and could lead to surface deformation over time.

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