The programme group "Ground water and geochemistry" embraces many fields of geoscience in order to enable deeper understanding of geological phenomena and their impacts on the consequences of human activity in the environment. Geological environment, as well as the processes taking place in it, is very complex and extensive. Its understanding and study, therefore, need to be a synergetic act of experts from different geological branches united in one programme group. The major objective of the programme group is to study anthropogenic and natural impacts on the environment depending on geology, because chemical and mineral composition, physical characteristics and structure of rocks, as well as the products of weathering, are determined by the characteristics of landscape: its resistance against natural catastrophes, water supply, fertility, vulnerability, earthquake hazard, morphology, slope stability and transport resistance, as well as toxicity and buffering abilities. The programme took part in the studies of natural and anthropogenic processes on the surface of the Earth. It also contributed to the basic knowledge of geological environment, as well as successfully save methodological problems of the investigations and practical work in the fields of environmental protection and water supply. The results of the research work of the programme group continue the line of systematic study of chemical and physical structure of Slovenia that are important for environmental protection and sustainable development planning of ground water management, spatial planning, protection against the consequences of natural disasters, exploration and exploitation of raw materials, construction of national infrastructural objects and their conservation. Ground water is the major source of drinking water in Slovenia. Considering current degree of environmental burden with urbanization and industry, ground water investigations play an important role in healthy and suitable drinking water supply, as well as in the protection of healthy life and natural environment. The results of our research will contribute to better understanding of the aquifers that are being pumped for drinking water. Our research of aquifers was concentrated mostly on extensive karst aquifer systems in the south-eastern Slovenia as well as karst - fissure aquifers of the Karavanke Mountains. Beside drinking water exploitation, also the protection of the resources must be considered. The results of our research gave us the directions for the protection of ground water against the impacts of non-hazardous, hazardous and radioactive waste disposal sites and roads. Roads as well as waste disposal sites are important potential pollutants of drinking water resources in Slovenia. With Slovenia becoming a member of EU and with the implementation of the EU legislation the demands for ground water protection have risen. In order to establish effective ground water protection it is compulsory to create effective data bases, but mostly to produce proper interpretations, which will serve as a basis for further decision making. Ground water in deep aquifers represents an important source of thermal and mineral water, which is one of the bases of more profitable and perspective economy branches in Slovenia. Our investigations will enable economical use of thermal and mineral waters and contribute to effective use of some catchments of such waters.