More Like this

1. A novel method to estimate baseflow using open-source well data

   https://doi.org/10.1007/s10040-026-03087-2  

   Celupica-Liu, Corrine; Ayres, Nicholas; Ge, Shemin (May 2026, Hydrogeology Journal)

   Abstract Baseflow, a proxy for groundwater discharge to streams, is vital for sustaining streamflow in periods of drought or low overland flow. Current methods for estimating baseflow include tracer-based approaches, which employ measurements of electrical conductivity, hydrochemical tracers, or environmental isotopes, and non-tracer-based approaches, such as graphical separation or numerical modeling. This technical note presents a novel, physics-based method for estimating baseflow using publicly available groundwater well data. The methodology was applied to the Roaring Fork River watershed in the Upper Colorado River Basin, USA. Groundwater level observations from 89 wells in the Roaring Fork River watershed were obtained for a 21-year period to interpolate mean static groundwater elevations. Hydraulic gradients toward the Roaring Fork River were elucidated from groundwater level contours. Hydraulic conductivity estimates in the shallow alluvium aquifer along the Roaring Fork River were obtained from pumping test data in 82 wells. On the basis of the average hydraulic gradient and the hydraulic conductivity estimates, a baseflow contribution of 9.6 m³/s from groundwater discharge was derived. This baseflow estimate divided by the measured mean annual streamflow results in a baseflow index of 0.6 for the Roaring Fork River watershed, compared to a baseflow index of 0.82 from graphical separation. Although no universally accepted ground-truth method for baseflow estimation exists, this study introduces a novel approach using groundwater flow physics. Given the scarcity of reliable, larger-scale baseflow estimates, and the importance of quantifying baseflow for water resource management, this study highlights the potential applicability of often underutilized groundwater data for hydrologic studies. 

   more » « less
2. New Predictors for Hydrologic Signatures: Wetlands and Geologic Age Across Continental Scales

   https://doi.org/10.1002/hyp.70080  

   Holt, Anne; McMillan, Hilary (February 2025, Hydrological Processes)

   In dry summer months, stream baseflow sourced from groundwater is essential to support aquatic ecosystems and anthropogenic water use. Hydrologic signatures, or metrics describing unique features of streamflow timeseries, are useful for quantifying and predicting these valuable baseflow and groundwater storage resources across continental scales. Hydrologic signatures can be predicted based on catchment attributes summarising climate and landscape and can be used to characterise baseflow and groundwater processes that cannot be directly measured. While past watershed‐scale studies suggest that landscape attributes are important controls on baseflow and storage processes, recent regional‐to‐global scale modelling studies have instead found that landscape attributes have weaker relationships with hydrologic signatures of these processes than expected compared to climate attributes. In this study, we quantify two landscape attributes, average geologic age and the proportion of catchment area covered by wetlands. We investigate if incorporating these additional predictors into existing large‐sample attribute datasets strengthens continental‐scale, empirical relationships between landscape attributes and hydrologic signatures. We quantify 14 hydrologic signatures related to baseflow and groundwater processes in catchments across the contiguous United States, evaluate the relationships between the new catchment attributes and hydrologic signatures with correlation analysis and use the new attributes to predict hydrologic signatures with random forest models. We found that the average geologic age of catchments was a highly influential predictor of hydrologic signatures, especially for signatures describing baseflow magnitude in catchments, and had greater importance than existing attributes of the subsurface. In contrast, we found that the proportion of wetlands in catchments had limited influence on our hydrologic signature predictions. We recommend incorporating catchment geologic age into large‐sample catchment datasets to improve predictions of baseflow and storage hydrologic signatures and processes across continental scales. 

   more » « less
3. A Decadal Survey of the Near‐Surface Seismic Velocity Response to Hydrological Variations in Utah, United States

   https://doi.org/10.1029/2024JB030689  

   Feng, Kuan‐Fu; Denolle, Marine; Lin, Fan‐Chi; van_Dam, Tonie (January 2026, Journal of Geophysical Research: Solid Earth)

   Abstract Ongoing climate change is leading to an increase in prolonged droughts and severe weather events, which are particularly pronounced in semi‐arid regions, such as the western United States. These extremes could have lasting social and environmental impacts. Continuous monitoring of near‐surface hydrological processes and groundwater resources provides helpful information for effective water resource management. The seismological signature of groundwater fluctuations is clear in the temporal variations in seismic velocities, dv/v. To this end, developing a proxy for groundwater level using dv/v represents an opportunity, but further understanding of the relation between dv/v and subsurface hydrology is required. In this study, we apply single‐station cross‐component correlation analysis to 28 broadband seismic stations in Utah between January 2006 and March 2023 and analyze the dv/v in the 2–4 Hz frequency band. To explain dv/v, we linearly superimpose thermoelastic stresses, soil moisture estimated from remote sensing data products, and a long‐term deep water table pore pressure. We find that the relative contributions of each depend on the location. Still, adding a long‐term water table decline, which is not systematically observed in soil moisture, better fits our data. We conclude that soil moisture alone does not explain the variations in total water storage when subsurface moisture is decoupled from the deep‐water table. We also conclude that dv/v can be used as a proxy for water storage. 

   more » « less
4. Trend Analyses of Baseflow and BFI for Undisturbed Watersheds in Michigan—Constraints from Multi-Objective Optimization

   https://doi.org/10.3390/w13040564  

   Hagedorn, Benjamin; Meadows, Christina (February 2021, Water)

   null (Ed.)

   Documenting how ground- and surface water systems respond to climate change is crucial to understanding water resources, particularly in the U.S. Great Lakes region, where drastic temperature and precipitation changes are observed. This study presents baseflow and baseflow index (BFI) trend analyses for 10 undisturbed watersheds in Michigan using (1) multi-objective optimization (MOO) and (2) modified Mann–Kendall (MK) tests corrected for short-term autocorrelation (STA). Results indicate a variability in mean baseflow (0.09–8.70 m3/s) and BFI (67.9–89.7%) that complicates regional-scale extrapolations of groundwater recharge. Long-term (>60 years) MK trend tests indicate a significant control of total precipitation (P) and snow- to rainfall transitions on baseflow and BFI. In the Lower Peninsula Rifle River watershed, increasing P and a transition from snow- to rainfall has increased baseflow at a lower rate than streamflow; an overall pattern that may contribute to documented flood frequency increases. In the Upper Peninsula Ford River watershed, decreasing P and a transition from rain- to snowfall had no significant effects on baseflow and BFI. Our results highlight the value of an objectively constrained BFI parameter for shorter-term (<50 years) hydrologic trend analysis because of a lower STA susceptibility. 

   more » « less
5. Monitoring Terrestrial Water Storage, Drought and Seasonal Changes in Central Oklahoma With Ambient Seismic Noise

   https://doi.org/10.1029/2023GL103419  

   Zhang, Shuo; Luo, Bingxu; Ben‐Zion, Yehuda; Lumley, David E.; Zhu, Hejun (September 2023, Geophysical Research Letters)

   Abstract Significant imbalances in terrestrial water storage (TWS) and severe drought have been observed around the world as a consequence of climate changes. Improving our ability to monitor TWS and drought is critical for water‐resource management and water‐deficit estimation. We use continuous seismic ambient noise to monitor temporal evolution of near‐surface seismic velocity,dv/v, in central Oklahoma from 2013 to 2022. The deriveddv/vis found to be negatively correlated with gravitational measurements and groundwater depths, showing the impact of groundwater storage on seismic velocities. The hydrological effects involving droughts and recharge of groundwater occur on a multi‐year time scale and dominate the overall derived velocity changes. The thermoelastic response to atmospheric temperature variations occurs primarily on a yearly timescale and dominates the superposed seasonal velocity changes in this study. The occurrences of droughts appear simultaneously with local peaks ofdv/v, demonstrating the sensitivity of near‐surface seismic velocities to droughts. 

   more » « less