Effect of temporal resolution of water level and temperature inputs on numerical simulation of groundwater–surface water flux exchange in a heavily modified urban river

Authors

  • Girma Yimer Ebrahim,

    Corresponding author
    • UNESCO-IHE Institute for Water Education, Department of Water Science and Engineering, Delft, The Netherlands
    Search for more papers by this author
  • Kelly Hamonts,

    1. Bio-Protection Research Centre, P.O. Box 84, Lincoln University, Lincoln, New Zealand
    2. VITO (Flemish Institute for Technological Research), Separation and Conversion Technology, Mol, Belgium
    Search for more papers by this author
  • Ann van Griensven,

    1. UNESCO-IHE Institute for Water Education, Department of Water Science and Engineering, Delft, The Netherlands
    Search for more papers by this author
  • Andreja Jonoski,

    1. UNESCO-IHE Institute for Water Education, Department of Water Science and Engineering, Delft, The Netherlands
    Search for more papers by this author
  • Winnie Dejonghe,

    1. VITO (Flemish Institute for Technological Research), Separation and Conversion Technology, Mol, Belgium
    Search for more papers by this author
  • Arthur Mynett

    1. UNESCO-IHE Institute for Water Education, Department of Water Science and Engineering, Delft, The Netherlands
    2. Faculty CiTG, Delft University of Technology, Delft, The Netherlands
    Search for more papers by this author

Correspondence to: Girma Yimer Ebrahim, Water Science and Engineering, UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA, Delft, The Netherlands.

E-mail: g.ebrahim@unesco-ihe.org

Abstract

Groundwater interacts with surface water features nearly in all types of landscapes. Understanding these interactions has practical consequences on the quantity and quality of water in either system, because the depletion or contamination of one of the systems will eventually affect the other one. Many studies have shown that the use of heat as natural tracer in conjunction with water level measurements is an effective method for estimating water flow (fluxes) between groundwater and surface water. A number of studies have explored the effects of spatial and temporal variability of groundwater–surface water flux exchanges using temperature and water level measurements; however, the effect of temporal resolution of water level and temperature data on estimating flux remains unexplored. Therefore, this study investigated the effect of temporal resolution of input data on temporal variation of groundwater–surface water flux exchanges. To this end, we calibrated a variably saturated two-dimensional groundwater flow and heat transport model (VS2DH) at hourly and daily time scales using temperatures measured at multiple depths below the riverbed of the Zenne River, located at a well-known Belgian brownfield site. Results of the study showed that the computed water flux through the streambed ranged between −32 mm/day and +25 mm/day using the hourly model and from −10 mm/day to −37 mm/day using the daily model. The hourly model resulted in detecting reversal of flow direction inducing short-term surface water flow into the streambed. However, such events were not captured if daily temperature and water level measurements were used as input. These findings have important implications for understanding contaminant mass flux and their attenuation in the mixing zone of groundwater and surface water. Copyright © 2012 John Wiley & Sons, Ltd.

Ancillary