Authors: Xueyi Li, Norm Jones, Gustavious Williams – Brigham Young University
Title: GWBASE: A Scalable Framework to Quantify Groundwater–Baseflow Correlations Using Paired Well and Streamflow Observations
Presentation Type: Poster Presentation
Abstract: As population and economic activity increase, demand for water continues to rise, placing growing pressure on drinking water supplies and intensifying the effects of drought. Groundwater plays a critical role in sustaining both human systems and natural hydrology. It supports drinking water, agriculture, and industry, and is a key contributor to streamflow through baseflow. Nearly half of all monitored wells in the United States have shown significant long-term declines due to extraction exceeding natural recharge.
To better understand the impact of declining groundwater on surface water systems, we focus on streamflow during baseflow-dominated (BFD) periods, when groundwater is the primary source of streamflow. We examine whether changes in groundwater levels are reflected in baseflow patterns by combining USGS daily streamflow records with groundwater level observations.
We present GWBASE (GroundWater–BASEflow correlation), a scalable algorithm that quantifies the relationship between changes in groundwater levels and stream baseflow. GWBASE links each monitoring well to the nearest stream segment, determines its watershed membership, and associates it with the terminal stream gage that integrates flow from the upstream basin. Daily groundwater levels are interpolated, and streamflow records are classified by BFD status using a machine learning model. For each BFD period, GWBASE calculates changes in streamflow (∆Q) and water table elevation (∆WTE) relative to the first BFD day. These metrics are aggregated at both the gage and basin levels to assess local and regional groundwater–streamflow interactions. The large basin is represented as the union of all terminal gage upstream areas.
We apply GWBASE to the Great Salt Lake Basin as a case study. The results reveal strong spatial variability in coupling strength, with some well–gage pairs showing clear correlations between groundwater decline and streamflow reduction. GWBASE offers a generalizable framework to assess hydrologic vulnerability and the role of groundwater in sustaining streamflow under drought conditions.