Application of snowmelt as an active and inexpensive dual isotope groundwater tracer

Abstract

The use of snowmelt as an inexpensive multi-component tracer solution for active aquifer characterization is investigated, creating a valid alternative to existing artificial water isotope labelling using enriched deuterium oxide (2 H 2 O) and water-18 O (H 2 18 O). The approach directly takes advantage of natural differences between groundwater and precipitation. It is shown, at laboratory-scale and small field-scale, that a direct injection of snowmelt into a porous medium allows for the tracing of water flow and, therefore, for the determination of transport parameters based on the stable isotope signatures (δ 2 H and δ 18 O) and on the sum parameter electrical conductivity (EC). The differences in the isotope signature between the snowmelt and groundwater applied in this study were significant, with Δ(δ 2 H) = 61.0‰ and Δ(δ 18 O) = 8.2‰, while the EC difference was~0.5 mS/cm. Stable isotope breakthrough was observed to be almost congruent to sodium chloride (laboratory tracer experiment) and to uranine (field-scale push-drift-pull test), clearly supporting the assumption of conservative transport. A crosscheck of the isotope data in δ 2 H-δ 18 O plots revealed no significant biases in the tests. On the other hand, the snowmelt's EC breakthrough suffered from a slight retardation due to ion exchange and mineral reactions.

Single‐Rate Dual‐Domain Mass Transfer Model: Elucidating Temperature Effects

“…This would, in turn, also affect the investigated exchange between mobile and immobile regions. All in all, the quality of match between the employed tracer signals is within the expected limits previously observed in lab‐scale (e.g., Binder, Burghardt, et al., 2019; Koeniger et al., 2010) and field‐scale (e.g., Binder, Tritschler, et al., 2019; Luhmann et al., 2012) experiments employing combinations of stable isotopes and other tracers such as dyes and salts.…”

Collected Rain Water as Cost‐Efficient Source for Aquifer Tracer Testing

“…Without having a gravel pack annulus, they are screened entirely within the highly permeable zone of the aquifer as well as the overlying sections (Händel et al 2016) As described by Dietze and Dietrich (2012), the shallow aquifer at the test site is consisting of highly heterogeneous sands and gravels of fluvial origins reaching from 7.5 to 13 m below ground surface (mbgs). Estimated hydraulic conductivities of the aquifer are ranging between 2 × 10 −4 and 3 × 10 −2 m/s (Dietze and Dietrich 2012;Binder et al 2019). The highest hydraulic conductivity value was determined by a pumping test at well #7.…”

“…As proposed by Binder et al (2019), natural precipitation water, specifically previously collected snowmelt, may be injected as groundwater tracer for purposes of aquifer exploration and characterization. Precipitation water has some distinct inherent characteristics that can differ significantly from the corresponding features of the local groundwater.…”