Modelling Groundwater-Surface water interaction in the Dinkel catchment

Vince Kaandorp, Perry de Louw, Marijn Kuijper, Ellis Penning, Hans Peter Broers, Ype van der Velde

The MARS project (“Managing Aquatic ecosystems and water resources under multiple stress”)

is funded by the European Union under the 7th Framework Programme, contract no. 603378.

Groundwater modelling and water quality in the Dinkel catchment

Regge and Dinkel (Waterboard Vechtstromen)

The Dinkel catchment

9 november 2015

Meandering streams

Riparian zones

In stream dead wood

But also…

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Straightening

Eutrophication

Obstacles

Intensive management

Loss of riparian zones

The Dinkel Catchment

The Dinkel Catchment

Groundwater is an important connection

between the stream and its catchment

• Amount and timing of discharge

e.g. baseflow

• Water chemistry

e.g. unpolluted water input

• Water temperature

buffers temperature, e.g. warm input in winter

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Why is groundwater important?

Groundwater influences surface water

streams:

The groundwater component: Baseflow index (BFI)

Hydrograph separation method

0.1 very flashy river 0.9 very stable river with a high base flow proportion

Base Flow Index

Springendalse Beek BFI 0.8

Voltherbeek BFI 0.4 Elsbeek BFI 0.4

Graphics of year 2006

Dinkelkanaal BFI 0.1

What is the contribution of groundwater to lowland streams?

Springs

Drainage

Different groundwater sources…

Flow paths and travel times are important!

The groundwater contribution is a mix of

different groundwater components,

which have specific flow paths and travel

times.

Part is shallow, young groundwater.

Another part is deep, old groundwater.

Components vary in water chemistry.

Groundwater components: Flow path & Travel Time

Modified from Van der Grift & Klein, 2001

? ? ? ? ?

Calculating groundwater Travel times

9 november 2015

1. Coupled Groundwater-Unsaturated zone model to calculate groundwater fluxes

iMOD + MetaSWAP

iMOD

Calculating groundwater Travel times

9 november 2015

1. Coupled Groundwater-Unsaturated zone model to calculate groundwater fluxes

iMOD + MetaSWAP

2. Particle tracking to calculate flow paths and travel times of infiltrating water

What is the contribution of groundwater to lowland streams?

Springendalse Beek

9 november 2015

Changing Groundwater contribution with changing discharge

Modified from Van der Grift & Klein, 2001

Water Quality and Groundwater contribution age

9 november 2015

Conclusions

9 november 2015

Groundwater:

• Specific chemical composition

• Sustains surface water flow

• Buffers temperature

The groundwater system should be included when trying to improve

aquatic ecological conditions in streams

The groundwater contribution varies throughout

the year

Impact on water quantity and quality