Subsurface Hydrology

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Research Focus

Subsurface water constitutes an important component of many water resource systems, supplying fresh water for domestic use, for industry and for agriculture. Management of subsurface water needs reliable predictions of the total amount of available water but also of water quality. Subsurface hydrological models are a valuable tool to deliver that information. Our group has the aim to develop regional subsurface hydrological models that on the one hand take into account subsurface heterogeneity that typically ranges from meter to kilometer scales but on the other hand are simplistic enough to be part of our mesoscale hydrological model system mHM. Our strong expertise in multiscale methods -ranging from homogenisation, stochastic to spatial filtering methods - helps to link complex small scale models with simplistic regional descriptions.


Group Members



Short Project Descriptions


AquaDiva: Modelling Catchment Dynamics Using Travel-Time Distributions

Analysis of catchment behavior using travel time distributions

The collaborated research centre (Sonderforschungsbereich) AquaDiva is dedicated to the investigation of how surface conditions and geology influence the functional biodiversity of the subsurface. Within this centre we are tasked with modelling the water and energy movement through the subsurface.

To that end, we apply the mesocsale Hydrological Model mHM , a spatially distributed hydrological model to the catchment of the AquaDiva observation site. Using detailed data of precipitation, land cover, morphology and soil type as inputs, mHM can determine fluxes like recharge and evapotranspiration and states like soil moisture as outputs.

Using these data, we apply the analytical framework developed by Botter et al. [2010, WRR] and Van der Velde et al. [2012, WRR] to quantify how the catchment stores and releases water. This allows for a description of the flow and transport dynamics taking place in the catchment. The spatial distribution of such dynamics can then be compared with land cover and soil moisture maps as well as driving forces like precipitation and temperature. Additionally we can determine the temporal evolution of mean travel times by using time series of all relevant hydrological processes from 1960-2010.

Determining statistical parameters of aquifer heterogeneity from pumping test data

pumping test
Simulated hydraulic head distribution for a pumping test in three-dimensional heterogeneous media.

We develop new schemes for interpreting pumping tests in heterogeneous aquifers by making use of adaptive multi-scaling techniques (Coarse Graining). Usually, the heterogeneous character of aquifers prevents a consistent interpretation of pumping tests based on Thiem's or Theis formula, since interpreting the aquifer as an equivalent homogeneous aquifer fails. The reason for this failure lies in an increased impact of heterogeneities due to steep gradients of the water flux close to the pumping well. Adaptive coarsening strategies allow for resolving steep gradients in adequate resolution.

The methods, we are developing allow to describe the drawdown of a pumping test in heterogeneous aquifer effectively. Thereby, we derive analytical or semi-analytical solutions for both steady state and transient pumping test in two and three dimensional porous media. In combination with numerical pumping tests we determine the ability of our approach to predict parameters of aquifer heterogeneity by inverse estimation. Furthermore we aim to adapt the procedure to conditions comparable to field site investigations. Sensitivity analysis indicate how accuracy and uncertainty of estimated parameters correlate to number and spatial distribution of head measurements. Thus heterogeneous structures of the aquifer can be identified.

A Filtered Density Function Approach to Uncertainty Assessments for Reactive Transport in Heterogeneous Porous Media

Particle_trajectories

Modelling contaminant transport in heterogeneous aquifers is a challenging task. The range of problems include the dominant role of mixing on reactive processes and the quantitive description of chemical kinetics.

The probability density function (pdf) approach has promising properties allowing to overcome most of these problems. Non-linear reaction terms appearing in the pdf evolution equations can be treated exactly and without any assumptions, for instance. Taking advantage of the pdf approach for flow in heterogeneous porous media we aim to derive an evolution equation for the pdf of groundwater flow.This derivation implies upscaling of equations by the coarse graining procedure.

With this work we hope to develop a robust tool for groundwater contamination risk assessments.

Theory and interpretation of transport experiments and field scale dispersivity

Macrodispersivity reduced
Macrodispersivities α of high and moderate reliability versus observation distance L (one value per aquifer).
Macrodispersivity reduced
Macrodispersivities α versus observation distance L for a few selected aquifers.

Transport by groundwater occurs over the different scales encountered by moving solute plumes. Spreading of plumes is often quantified by the longitudinal macrodispersivity α. It was found that generally α is scale dependent, increasing with the travel distance L of the plume centroid, stabilizing eventually at a constant value (lower Figure).

It was surmised in the literature that α scales up with travel distance L following a universal scaling law. Attempts to define the scaling law, including theoretical justifications, were pursued by fitting a regression line in the log-log representation of results from an ensemble of field experiment, primarily those summarized by Gelhar et al, 1992. Despite concerns raised about universality of scaling laws, such relationships are being employed by practitioners for modeling multiscale transport. They, presumably, offer a convenient prediction tool, with no need for detailed site characterization.

We revisited the concept of universal scaling through detailed analyses of field data, coupled with a thorough re-evaluation of the reliability of the reported α values. Our investigation concludes that transport, and particularly α, is formation-specific, and that modelling of transport cannot be relegated to a universal scaling law. Instead, transport requires characterization of aquifer properties, e.g. spatial distribution of hydraulic conductivity, and the use of adequate models.

Contact: Alraune Zech , Sabine Attinger , Alberto Bellin, Vladimir Cvetkovic, Gedeon Dagan, Peter Dietrich , Aldo Fiori, Yoram Rubin, Georg Teutsch

Hydrological Models and Scaling Effects

The subsurface is affected by high heterogeneity at different spatial scales, from meter to kilometer scales. For this reason, the parametrization of subsurface hydrological models has been recognized as a crucial step for a correct prediction of water flux and transport. More recently, with the advance in computing science and the development of fully coupled hydrological models, it was further emphasized the need of a unified framework to cross and integrate the results obtained from several disciplines, in hydrogeology, soil hydrology and surface hydrology.

Aim of the project is to identify the scaling effects for different hydrological processes, from groundwater recharge to surface run off, to quantify the uncertainty due to unresolved heterogeneity and, finally, to develop a unified data assimilation framework that takes into account different variables (e.g., river discharge and soil moisture) to improve the model performances.

The integrated hydrological model Parflow.CLM is used for these aims. Numerical tests are implemented at different temporal and spatial scales, ranging from hillslope to catchment scales. Specific analyses are conducted based on a virtual reality that mimics the Neckar catchment (Germany). Simplifications of the model complexity are evaluated to define features to integrate in conceptual hydrological models.

DFG project: FOR2131

Partners: University of Bonn, Forschungszentrum Jülich (FZJ), Hannover University, University of Tübingen, University of Hamburg, University of Augsburg.


Former Projects

A discription of former projects is given at the  former project page and the former research group's page .


Teaching

  • Geostatistics Homepage

    Friedrich-Schiller-University Jena, Institute for Hydrogeology, Bachelor and Master in Geoscience, Biogeoscience and related subjects

    Katharina Ross , Sabine Attinger

  • Modelling Flow Homepage

    Friedrich-Schiller-University Jena, Institute for Hydrogeology, Bachelor and Master in Geoscience, Biogeoscience and related subjects

    Katharina Ross , Sabine Attinger

  • Modelling Transport Homepage

    Friedrich-Schiller-University Jena, Institute for Hydrogeology, Bachelor and Master in Geoscience, Biogeoscience and related subjects

    Katharina Ross , Sabine Attinger

  • Dry land hydrology - Irrigation and agricultural hydrology Homepage

    University of Potsdam, Institute for Earth and Environmental Science, Master in geoecology

    Gabriele Baroni


  • Numerical methods and simulation - Uncertainty and sensitivity analysis Homepage

    University of Potsdam, Institute for Earth and Environmental Science, Master in geoecology

    Gabriele Baroni

  • Computational Fluid Dynamics Homepage

    Magdeburg - Stendal University of Applied Sciences, International Master of Water Engineering

    Falk Hesse


  • Mathematics and Modelling Homepage

    Magdeburg - Stendal University of Applied Sciences, Master of Water Engineering

    Falk Hesse


  • Modelling Flow and Transport in the Subsurface Homepage

    Magdeburg - Stendal University of Applied Sciences, Master of Water Engineering

    Falk Hesse



Publications

2019 (6)

2018 (5)

2017 (4)

2016 (13)

2015 (10)

2014 (6)

2013 (10)

2012 (3)

2011 (6)

2010 (9)

2009 (4)

2008 (3)

2007 (1)

2006 (2)

2005 (1)

2004 (4)

2003 (5)

2002 (5)

2001 (3)

2000 (2)