Institute of Geological Sciences

Research RWI

Geochemistry of Aquifers

Artesian groundwater occurrence in the Najd desert, Sultanate of Oman (Photo H.N. Waber)

In our research regarding the geochemistry of aquifers we focus on the composition and evolution of groundwater circulating in aquifers as well as on the geological and petrophysical aspects of the aquifer material.

Groundwater constitutes worldwide the major resource for drinking water. Understanding the hydrological cycle from the infiltration into the underground to its discharge into surface water bodies and finally the sea is essential for groundwater management and protection plans. We are conducting research on the chemical evolution of groundwater and its residence in the underground on a local and regional scale. With such isotope hydrochemical investigations and the aid of geochemical and transport modelling tools we aim to derive quantitative information about the quality, the vulnerability with respect to contamination, renewal times and flow paths of groundwater in near-surface environments and the deep underground.

Idiomorphic quartz and calcite in water-conducting zone of a fractured aquifer indication equilibrium between these minerals and groundwater (Photo H.N. Waber)

Investigations of the aquifer material are conducted in support of understanding and constraining groundwater evolution and aim at the chemical and isotope composition of the water-conducting zones applying solid phase analytical techniques.

Near-surface Environments

Most of groundwater presently used for drinking water and irrigation purposes is derived from the near-surface environment of the hydrosphere. Groundwater percolating in this thin sub-surface layer of a few decametres at the most derives its mineralisation depending on the rock type(s) it encounters along its flow path. This results in distinct groundwater compositions depending on the aquifer composition (e.g. Molasse sandstone, limestone, evaporate and crystalline rocks) and different degrees of vulnerability of groundwater. Consequently, anthropogenic influences such as industrial, geothermal energy, and agricultural activities, underground constructions etc. on the near-surface groundwater environment may have a different impact on the groundwater quality.

Deep Groundwater

The increasing demand on groundwater paralleled by the increasing interest in the geologic underground for energy resources (e.g. geothermal energy , oil, gas), waste disposal (e.g. radioactive waste, CO2 sequestration ), industrial constructions (e.g. railway and motorway tunnels) and social use (e.g. mineral water, hot spring resorts) requires knowledge about composition, residence time, flow paths and regional distribution of deep groundwater occurrences.

Groundwater Contamination

Groundwater is commonly regarded as contaminated as soon as contaminant concentrations surpass those of the natural background. The degree at which contamination by a specific compound may interfere with the usage of groundwater as drinking, irrigation and industrial water supplies is regulated in most countries by law and the recommended values of international organisations such as the WHO.