Characterizing groundwater contribution to ecologically valuable lowland streams using Travel Time Distributions — ASN Events
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  3. Characterizing groundwater contribution to ecologically valuable lowland streams using Travel Time Distributions

Characterizing groundwater contribution to ecologically valuable lowland streams using Travel Time Distributions (#237)

Vince Kaandorp 1 2 , Perry de Louw 2 , Marijn Kuijper 2 , Ype van der Velde 3 , Hans Peter Broers 4
  1. Geochemistry, Utrecht University, Utrecht, The Netherlands
  2. Subsurface and Groundwater Systems, Deltares, Utrecht, The Netherlands
  3. Soil Geography and Landscape, Wageningen University, Wageningen, The Netherlands
  4. TNO Geological Survey, Utrecht, The Netherlands

Many European surface waters are currently failing the ecological guidelines set by the Water Framework Directive. This issue is being researched in the EU FP7 project Managing Aquatic ecosystems and water Resources under multiple Stressors (MARS) by focusing on the effect of multiple stressors. The current study, which is part of this project, examines the importance of groundwater for aquatic ecology.

Groundwater is the main source of stream flow for lowland streams and therefore affecting abiotic habitat conditions of aquatic ecology.The groundwater contribution to streams influences (1) river discharge, (2) water quality, (3) temperature and (4) the riparian zone. The input of groundwater provides streams with a stable base flow, good quality water and a steady temperature. However, the groundwater contribution to streams is often not characterized in detail. The current research addresses the groundwater input and its importance for aquatic ecology in lowland streams, and aims to characterize it in a more sophisticated way using Dynamic Travel Time Distributions.

A 3D groundwater model (MODFLOW) was used to characterize daily Travel Time Distributions in the Dinkel lowland catchment in The Netherlands. This revealed varying contributions of groundwater flow paths with different travel times. Longer and shorter flow paths differ in amount and timing of flow, hydrochemistry and temperature. Results can be used to study the effect of stresses on the groundwater component of stream flow, and the aquatic ecosystems and habitats present in the stream.

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