Jens-Olaf Delfs

Christian-Albrechts-Universität zu Kiel | CAU · Department of Geosciences

It is a requirement for the implementation of the CO2 - geostorage technology that the long-term fate of injected CO2 into the subsurface is understood. Dissolution trapping is known as a long-term process that able to reduce the leakage risk of the gas phase of CO2 from a reservoir. This study, therefore, examines the influence of convective flow...

Upward displacement of brine from deep geological formations poses a potential threat to near surface drinking water resources. In this work, the impact of a layered sequence of hydraulically permeable and impermeable layers, connected by a vertical fluid pathway like e.g. a fault is investigated using an idealized scenario and numerical process si...

Upward displacement of brine from deep geological formations poses a potential threat to near-surface drinking water resources. In this work, the impact of a layered sequence of hydraulically permeable and impermeable layers connected by a vertical fluid pathway like, e.g., a fault is investigated using an idealized scenario and numerical process s...

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Brine intrusion into drinking water resources induced by energy or carbon storage operations in the deep subsurface are a major concern when employing these storage options. A modeling study of salt leakage from a deep storage formation into a drinking water aquifer is conducted, where brine leakage is induced by injection of salt water. Results sh...

Catchments are complex, but can be understood by examining processes of its individual compartments stream, overland, soil, aquifer and the manner they interact. Thus, this paper presents a modeling framework that supports a comprehensive analysis of the interactions and feedbacks. Governing partial differential equations are coupled by leakance at...

This paper evaluates the remediation potential of a salinized coastal aquifer by utilizing a scenario simulation. Therefore, the numerical model OPENGEOSYS is first validated against analytical and experimental data to represent transient groundwater level development and variable density saline intrusion. Afterwards, a regional scale model with a...

There is a growing number of large scale, complex hydrologic models with fully 2D and 3D formulations that seek to combine surface and subsurface flow. Many of these models are coupled to land-surface energy balances, biogeochemical and ecological process models, and atmospheric models. Although they are being increasingly applied for hydrologic pr...

Agricultural practices impact soils and the wider environment (groundwater, receiving water courses and ponds, etc.) with various feedback loops. For instance, groundwater extraction may increase infiltration rates and nitrate leaching from the plant root zone. To assess such inter-compartment feedbacks with a numerical model, the object-oriented m...

This poster presents an open-source framework designed to assist water scientists in the study of catchment hydraulic functions with associated chemical processes, e.g. contaminant degradation, plant nutrient turnover. The model successfully calculates the feedbacks between surface water, subsurface water and air in standard benchmarks. In specific...

Carbon dioxide Capture and Storage (CCS) technology is known for disposing a specific amount of CO2 from industrial release of flue gases into a suitable storage where it stays for a defined period of time in a safe way. Types of storage sites for CO2 are depleted hydrocarbon reservoirs, unmineable coal seams and saline aquifers. In this poster, we...

In this paper we describe the OpenGeoSys (OGS) project, which is a scientific open-source initiative for numerical simulation of thermo-hydro-mechanical/chemical processes in porous media. The basic concept is to provide a flexible numerical framework (using primarily the Finite Element Method (FEM)) for solving multifield problems in porous and fr...

This paper presents an inter-compartment boundary condition for the simulation of surface runoff, soil moisture, and soil air as a coupled system of partial differential equations. The boundary condition is based on a classic leakance approach to balance water between differently mobile regions such as the land surface and subsurface. Present work...

In geological formations, migration of CO2 plume is very complex and irregular. To make CO2 capture and storage technology feasible, it is important to quantify CO2 amount associated with possible leakage through natural occurring faults and fractures in geologic medium. Present work examines the fracture aperture effect on CO2 migration due to fre...

Current research into CO2 capture and storage is dominated by improving the CO2 storage capacity. In this context, risk related to CO2 leakage is an important issue which may cause environmental problems, particularly when freshwater resources nearby are intruded by the CO2 plume. In this work, the leakage into a multi-layered fractured saline aqui...

This work introduces the soil air system into integrated hydrology by simulating the flow processes and interactions of surface runoff, soil moisture and air in the shallow subsurface. The numerical model is formulated as a coupled system of partial differential equations for hydrostatic (diffusive wave) shallow flow and two-phase flow in a porous...

Sustainable water quality management requires a profound understanding of water fluxes (precipitation, run-off, recharge, etc.) and solute turnover such as retention, reaction, transformation, etc. at the catchment or landscape scale. The Water and Earth System Science competence cluster (WESS, http://www.wess.info/) aims at a holistic analysis of...

This paper deals with numerical modeling of groundwater systems. We present the implementation of an approach to solve a moving boundary problem for a dynamic water table within an invariant finite element mesh. The modeling software is successfully validated against laboratory experiment data for an unconfined, density-dependent benchmark. The val...

OpenGeoSys solves the balance equations for mass, momentum, and energy conservation in a coupled manner. The porous medium approach represents multi-phase, multi-component systems. A large variety of equations-of-state and constitutive laws allow for different environmental applications

In this paper we describe the OpenGeoSys (OGS) project, which is a scientific open-source initiative for numerical simulation of thermo-hydro-mechanical-chemical processes in porous media. The basic concept is to provide a flexible numerical framework (using primarily the Finite Element Method (FEM)) for solving multifield problems in porous and fr...

Benchmarking coupled surface-subsurface flow models becomes more important as they are increasingly used for operational purposes (e.g. in water management) and long-term analysis (e.g. in climate change research). For this reason we inter-compare the hydrogeological models HydroGeoSphere and OpenGeoSys and present results with emphasis on the para...

The aim of this example is to simulate the stationary groundwater flow in an anisotropic porous medium. In order to consider the permeability anisotropy, a 2-D numerical model is built which contains a higher permeability in the vertical direction than that in the horizontal direction. The aquifer is assumed saturated and stationary.KeywordsPorous...

Numerical modeling of interacting flow and transport processes between different hydrological compartments, such as the atmosphere/land surface/vegetation/soil/groundwater systems, is essential for understanding the comprehensive processes, especially if quantity and quality of water resources are in acute danger, like e.g. in semi-arid areas and r...

Benchmarking hydrological models becomes more important as they are increasingly used for operational purposes e.g. in water management and long-term analysis e.g. in climate change research. We verify and compare the simulation platforms HydroGeoSphere and OpenGeoSys regarding flow and solute transport in coupled surface-soil hydrosystems. The num...

Numerical modelling of interacting flow processes between roots and soil is essential for understanding the influence of different root geometries and types on the hydro-system. This technical contribution will describe the coupling of two software tools to enable the analysis of water uptake of plant communities, one modelling the water flow along...

In soil-vegetation-atmosphere transfer (SVAT) models, root water uptake is implemented as a sink term in the 1-dimensional (vertical) Richards Equation. Commonly, vertical root water uptake profiles are related to the product of rooting density distribution and a water stress factor. This representation leads to early limitation of uptake when the...

Hydrosystems are very complex systems with numerous processes occurring simultaneously at different spatial and temporal scales. We present an Euler-Lagrange approach for the analysis of flow and transport processes in coupled hydrosystems. Hydrological processes are described by diffusion equations (the diffusive wave approximation for overland fl...

Hydrosystems are very complex systems with numerous processes occuring simultaneously at different spatial and temporal scales. In this paper we present the concept of a compartment approach for the analysis of coupled hydrosystems including heat and mass transport. In this concept, flow and transport processes are coupled via their compartment (or...

We present a sensitivity analysis for infiltration excess (Hortonian) overland flow based on a classic lab-oratory experiment by Smith and Woolhiser [Smith RE, Woolhiser DA. Overland flow on an infiltrating surface. Water Resour Res 1971;7(4):899–913]. The model components of the compartment approach are comprised of a diffusive wave approximation...

A parallelized large-scale regional hydrologic soil model (RHSM) is developed as a tool for large-scale unsaturated zone investigations. It is applied to simulate the temporal and spatial responses of the unsaturated zone and the regional water budget under the forcing of realistic precipitation and evaporation scenarios. The Richards equation is u...

In this paper we present an object-oriented concept for numerical simulation of multi-field problems for coupled hydrosystem analysis. Individual (flow) processes modelled by a particular partial differential equation, i.e. overland flow by the shallow water equation, variably saturated flow by the Richards equation and saturated flow by the ground...

The fate and transport of Cryptosporidium parvum oocysts affecting groundwater involves processes at the surface and in the subsurface which are impacted by hydrological events and human and animal activities. In these coupled systems, numerical modelling is crucial to assess how oocysts deposited at the surface may influence the quality of groundw...

The soil compartment is an important interface between the atmosphere and the subsurface hydrosphere. In this paper a conceptual approach for regional hydrologic soil modelling (RHSM) is presented, which provides two important qualities for modelling. First, the soil compartment is directly coupled to the atmosphere via the land surface and to the...

Sustainable river basin management often requires an integrated under-standing of surface-subsurface flow and transport processes. The software framework OpenGeoSys (OGS) and the EPA Storm Water Management Model (SWMM) have been coupled to accomplish this. In this work OGS simulates flow in confined and unconfined aquifers applying the Darcy equati...