Constraining the Modern Hydrological Balance of Bear Lake, Utah‐Idaho: Insights From Stable Isotopes (δ18O and δ2H)

Abstract Freshwater lakes are vital water resources, especially in the context of a changing climate. Supplementing existing hydrological methods to monitor lake levels may greatly improve resource management, particularly in drought‐prone regions. In this study, we performed dual‐isotope (δ18O and...

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Main Authors: M. J. Custado, C. A. Gagnon, B. Belanger, N. Sekhon, J. Bernstein‐Schalet, C. W. Kinsley, W. D. Sharp, J. L. Oster, D. E. Ibarra
Format: Article
Language:English
Published: Wiley 2025-04-01
Series:Water Resources Research
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Online Access:https://doi.org/10.1029/2024WR038264
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Summary:Abstract Freshwater lakes are vital water resources, especially in the context of a changing climate. Supplementing existing hydrological methods to monitor lake levels may greatly improve resource management, particularly in drought‐prone regions. In this study, we performed dual‐isotope (δ18O and δ2H) calculations to model the hydrological balance of Bear Lake, Utah‐Idaho. The lake is a critical water resource and site for paleoclimate studies of the latest Pleistocene. Using the Craig‐Gordon isotopic mass balance model, we simultaneously constrained unknown fluxes, including groundwater discharge and particularly evaporation, which is typically under‐constrained due to inconsistencies across existing methods. Data from community databases and sampling campaigns in 2022 and 2023 were utilized to derive an evaporation rate of 2.18 × 108 m3/yr (±4.94 × 106 m3/yr, 1σ using δ18O; ±3.47 × 106 m3/yr, 1σ using δ2H) at a calculated relative humidity of 0.62 above the lake. Detailed analysis of the sensitivity of the model revealed that parameters related to atmospheric moisture, particularly humidity and its isotopic composition, significantly influence evaporation estimates. Using carbonate‐based isotope data, we leveraged this sensitivity to provide insights in the evaporation and humidity at Bear Lake during different time periods. This study shows the potential of using modern water isotopic composition to aid with interpreting carbonate‐based paleoclimate data sets and informing current and future water resource management practices.
ISSN:0043-1397
1944-7973