Geochemical Quantification of Semiarid Mountain Recharge

Abstract

Analysis of a typical semiarid mountain system recharge (MSR) setting demonstrates that geochemical tracers help resolve the location, rate, and seasonality of recharge as well as ground water flowpaths and residence times. MSR is defined as the recharge at the mountain front that dominates many semiarid basins plus the often-overlooked recharge through the mountain block that may be a significant ground water resource; thus, geochemical measurements that integrate signals from all flowpaths are advantageous. Ground water fluxes determined from carbon-14 ((14)C) age gradients imply MSR rates between 2 x 10(6) and 9 x 10(6) m(3)/year in the Upper San Pedro Basin, Arizona, USA. This estimated range is within an order of magnitude of, but lower than, prior independent estimates. Stable isotopic signatures indicate that MSR has a 65% +/- 25% contribution from winter precipitation and a 35% +/- 25% contribution from summer precipitation. Chloride and stable isotope results confirm that transpiration is the dominant component of evapotranspiration (ET) in the basin with typical loss of more than 90% of precipitation-less runoff to ET. Such geochemical constraints can be used to further refine hydrogeologic models in similar high-elevation relief basins and can provide practical first estimates of MSR rates for basins lacking extensive prior hydrogeologic measurements.

Isotopes as Tracers of Water Origin in and Near a Regional Carbonate Aquifer: The Southern Sacramento Mountains, New Mexico

“…In the Spring Mountains, Nevada, another carbonate-rock range, winter precipitation is dominant; summer rain contributes about 30% of annual precipitation, but only about 10% of recharge [23]. Winter recharge also predominates in the Huachuca Mountains, Arizona, where summer precipitation contributes 54% of the annual total on average, but winter precipitation accounts for 65% ± 25% of recharge [24]. In the Santa Catalina Mountains, Arizona [25], and the ranges delimiting the Verde River watershed, Arizona [26], winter recharge is considered predominant, contributing 98% of recharge in the latter case.…”

Isotopic paleoecology of Clovis mammoths from Arizona

“…Clovis mammoths consumed diets high in C 4 plants and drank water with Table S3). The δ 18 O values of meteoric water (and river, lake, or groundwater with meteoric water inputs) in most continental locations, including the modern SPV, are higher in summer and lower in winter (20,30,32,33). Thus, the peaks in the δ 18 O and δ 13 C curves in Clovis mammoths almost certainly represent summer, and the troughs, winter.…”

Seasonality of Groundwater Recharge in the Basin and Range Province, Western North America

“…Methods for partitioning groundwater recharge into mountain system recharge and flood recharge, and their relationship to streamflow have been thoroughly developed, and include the water budget method , empirical modeling (Ajami et al, 2011&2012), coupled land-surface modeling Serrat-Capdevila et al, 2013), geochemical methods (Plummer et al, 2004;Manning, 2011), and isotopic methods (e.g., Winograd et al, 1998;Eastoe et al, 2004;Thiros and Manning, 2004;Druhan et al, 2008;Wahi et al, 2008;Jasechko et al, 2014).…”