Fully integrated surface-subsurface flow modelling of groundwater-lake interaction in an esker aquifer: Model verification with stable isotopes and airborne thermal imaging

Pertti Ala-aho*, Pekka M. Rossi, Elina Isokangas, Bjørn Kløve

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)

Abstract

Water resources management is moving towards integration, where groundwater (GW), surface water (SW) and related aquatic ecosystems are considered one management unit. Because of this paradigm shift, more information and new tools are needed to understand the ecologically relevant fluxes (water, heat, solutes) at the GW-SW interface. This study estimated the magnitude, temporal variability and spatial distribution of water fluxes at the GW-SW interface using a fully integrated hydrological modelling code (HydroGeoSphere). The model domain comprised a hydrologically complex esker aquifer in Northern Finland with interconnected lakes, streams and wetlands. The model was calibrated in steady state for soil hydraulic conductivity and anisotropy and it reproduced the hydraulic head and stream baseflow distribution throughout the aquifer in both transient and steady state modes. In a novel analysis, model outputs were compared with the locations and magnitude of GW discharge to lakes estimated using field techniques. Spatial occurrence of GW-lake interaction was interpreted from airborne thermal infrared imaging. The observed GW inflow locations coincided well with model nodes showing positive exchange flux between surface and subsurface domains. Order of magnitude of simulated GW inflow to lakes showed good agreement with flux values calculated with a stable water isotope technique. Finally, time series of GW inflow, extracted as model output, showed moderate annual variability and demonstrated different interannual inflow changes in seepage and drainage lakes of the aquifer.Overall, this study demonstrated the ability of a fully integrated numerical model to reproduce observed GW-SW exchange processes in a complex unconfined aquifer system. The model-based estimates obtained for GW influx magnitude and spatial distribution, along with information on GW quality can be used to estimate ecologically relevant fluxes in future water resources management.

Original languageEnglish
Pages (from-to)391-406
Number of pages16
JournalJournal of Hydrology
Volume522
Early online date5 Jan 2015
DOIs
Publication statusPublished - Mar 2015

Bibliographical note

This study was made possible by the funding from EU 7th Framework programme GENESIS (Contract Number 226536), Academy of Finland AKVA research program, the Renlund Foundation, VALUE doctoral school and Maa- ja vesitekniikan tuki ry. We thank the people in Waterloo, Edward Sudicky, Rob McLaren, Young-Jin Park, Hyoun-Tae Hwang, and Jason Davison, for their assistance with HGS software. Kirsti Korkka-Niemi and Anne Rautio from the University of Helsinki are acknowledged for their help in planning and performing the airborne thermal imaging campaign. Thank you for Jarkko Okkonen (GTK) for valuable comments and discussions along the research project and Mary McAfee for manuscript language check. We would like to express our gratitude to Geological survey of Finland, Finnish meteorological institute, Finnish environmental administration and National land survey of Finland for providing datasets and expert knowledge that made this study possible in its current extent.

Keywords

  • Airborne thermal imaging
  • Esker aquifer
  • Fully integrated
  • Groundwater-surface water interaction
  • Numerical modelling
  • Surface-subsurface

Fingerprint

Dive into the research topics of 'Fully integrated surface-subsurface flow modelling of groundwater-lake interaction in an esker aquifer: Model verification with stable isotopes and airborne thermal imaging'. Together they form a unique fingerprint.

Cite this