Ground Water Recharge and Flow Characterization Using Multiple Isotopes

Abstract

Stable isotopes of delta(18)O, delta(2)H, and (13)C, radiogenic isotopes of (14)C and (3)H, and ground water chemical compositions were used to distinguish ground water, recharge areas, and possible recharge processes in an arid zone, fault-bounded alluvial aquifer. Recharge mainly occurs through exposed stream channel beds as opposed to subsurface inflow along mountain fronts. This recharge distribution pattern may also occur in other fault-bounded aquifers, with important implications for conceptualization of ground water flow systems, development of ground water models, and ground water resource management. Ground water along the mountain front near the basin margins contains low delta(18)O, (14)C (percent modern carbon [pmC]), and (3)H (tritium units [TU]), suggesting older recharge. In addition, water levels lie at greater depths, and basin-bounding faults that locally act as a flow barrier may further reduce subsurface inflow into the aquifer along the mountain front. Chemical differences in ground water composition, attributed to varying aquifer mineralogy and recharge processes, further discriminate the basin-margin and the basin-center water. Direct recharge through the indurated sandstones and mudstones in the basin center is minimal. Modern recharge in the aquifer is mainly through the broad, exposed stream channel beds containing coarse sand and gravel where ground water contains higher delta(18)O, (14)C (pmC), and (3)H (TU). Spatial differences in delta(18)O, (14)C (pmC), and (3)H (TU) and occurrences of extensive mudstones in the basin center suggest sluggish ground water movement, including local compartmentalization of the flow system.

Geochemistry analysis and evolution of a bolson aquifer, basin and range province in the southwestern united states

“…1; Chowdhury et al 2008). The Presidio Bolson is much larger than the Redford Bolson, which is south of Presidio.…”

“…The geochemical study of aquifers and surface water within the PRB conducted by Chowdhury et al (2006Chowdhury et al ( , 2008 was broad in scope and focused on groundwater recharge. It, however, did not fully address equilibrium calcium carbonate chemistry.…”

“…The study area is characterized by a hot desert climate. The average annual rainfall ranges from about 20 cm in the basin center to about 46 cm at the highest elevations (about 2,300 m) in the adjacent mountains (Chowdhury et al 2008).…”

“…Abstract This paper expands significantly on the majorion geochemical characterization, evolution, and differentiation of groundwater in the Presidio-Redford Bolson (PRB) Aquifer of Texas as presented in Chowdhury et al (2008). For 19 groundwater samples from the PRB Aquifer, the author calculated major cation-anion balance errors, equilibrium carbon dioxide partial pressure values and saturation indices for selected minerals.…”

Groundwater flow dynamics in the complex aquifer system of Gidabo River Basin (Ethiopian Rift): a multi-proxy approach

“…Clark and Fritz 1997;Herczeg et al 2001). These techniques were previously employed for investigations of the hydrogeology of active rift systems such as the East African Rift, Dead Sea Rift and Rio Grande Rift (Salameh and Rimawi 1984;Kebede et al 2008;Chowdhury et al 2008;Bretzler et al 2011). In such tectonic settings, variable lithology due to different episodes of volcanic eruptions, high geothermal gradients and emergence in the rift of mantle gases (e.g.…”