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Where groundwater seeps: Evaluating modeled groundwater discharge patterns with thermal infrared surveys at the river-network scale

Advances in Water Resources
By: , , , , , and 
https://doi.org/10.1016/j.advwatres.2021.104108

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Abstract

Predicting baseflow dynamics, protecting aquatic habitat, and managing legacy contaminants requires explicit characterization and prediction of groundwater discharge patterns throughout river networks. Using handheld thermal infrared (TIR) cameras, we surveyed 47 km of stream length across the Farmington River watershed (1,570 km2; CT and MA, USA), mapping locations of bank and waterline groundwater discharges based on their thermal signature. Using the observed groundwater discharge locations and predicted groundwater discharge rates from 6 variations of a numerical groundwater-flow model (MODFLOW-NWT), we compared 1) predicted groundwater-discharge rates in areas with and without observed groundwater discharge, 2) spatial patterns of observed and predicted groundwater discharge locations, and 3) density of observed groundwater discharge locations with predicted discharge rates. Five of six models reasonably predicted the spatial patterns of discharge locations along the 5th order mainstem, but fewer models predicted groundwater discharge patterns in smaller streams. Our results highlight 1) the feasibility of using TIR observations to evaluate groundwater models, 2) model parameters that influence discharge prediction accuracy (riverbed sediment and bedrock hydraulic conductivity and river-aquifer connections), and 3) current strengths and future opportunities for improved modeling of groundwater-discharge patterns.

    Study Area

    Publication type Article
    Publication Subtype Journal Article
    Title Where groundwater seeps: Evaluating modeled groundwater discharge patterns with thermal infrared surveys at the river-network scale
    Series title Advances in Water Resources
    DOI 10.1016/j.advwatres.2021.104108
    Volume 106
    Year Published 2022
    Language English
    Publisher Elsevier
    Contributing office(s) New England Water Science Center
    Description 104108, 14 p.
    Country United States
    State Connecticut, Massachusetts
    Other Geospatial Farmington River Watershed
    Google Analytic Metrics Metrics page
    Additional publication details