Original paper

The Krefeld-Meeting - Summary for members of the International Association of Hydrogeologists (I. A. H.)

Langguth, Horst Robert


1. General remarks The National Committee of the Federal Republic of Germany of the I.A.H. is very pleased to present you this paper containing the text of lectures given at the session at Krefeld (North Rhine Westphalia), from April 20 to April 24, 1970. It was the second meeting summoned by the German National Committee. The first one took place at Bad Salzuflen (North Rhine Westphalia) in 1966. There, about 50 hydrogeologists discussed in detail a small number of papers on the field of hydrogeology and hydrochemistry. Such a type of session proved to be very successful. By reason of this success, and obeying a suggestion of our member, Prof. Dr. W. RICHTER, we invited two other scientific societies in West Germany dealing with water problems to prepare a joint session on ground water problems. These two organisations are the section "Hydrogeology" of the "Deutsche Geologische Gesellschaft" and the section "Geochemistry" of the "Deutsche Mineralogische Gesellschaft". Topics of the session to be held should be the relations between ground water and surface water with particular respect to the amount of base flow contributing to stream runoff, the chemical processes occuring when water percolates through soil and subsoil and dissolves minerals on its way down to the water table. Experts engaged in these fields of research were invited to give lectures on their investigations. According to the invitations, almost all lectures were restricted to the proposed main topics: 11 lectures on two days on "relations between ground water and surface water", 16 lectures on two days on "geochemistry of surface and subsurface water". More than 250 colleagues including guests of eight foreign countries attended the Krefeld session. Summaries of the papers on geochemical problems are already published in "Zeitschrift der Deutschen Mineralogischen Gesellschaft". The text of all lectures of the first part as well as a few of the second one are summarized in the present special edition of "Zeitschrift der Deutschen Geologischen Gesellschaft". We are indebted to the sections "Hydrogeology" and "Geochemistry" of the societies mentioned above as well as to all the unnamed ones who made the session at Krefeld a success due to their participation. Furthermore, we are much obliged the presidency of the "Deutsche Geologische Gesellschaft" which managed the printing of this special issue, permitting us sending a copy to each member of the I.A.H. 2. Report on publications of the special issue of "Zeitsdhrift der Deutschen Geologischen Gesellschaft, Sonderheft" 2.1. Hydrogeologic part After LIMPRICH, methods of determining the rate of recharge to aquifers as function of the amount of precipitation within the catchment area can be subdivided into five groups: - deterministic hydrologic methods; - stochastic hydrologic methods; - analytical hydrologic methods; - analytical geologic methods; - inductive geologic methods. In Germany particularly hydrologic methods were applied for solving these problems. Reasons are that predominantly unconfined aquifers have been developed, and that there exists a relatively dense network of river gages and observation wells which are in use through decades. "Rahmenplane" as lay out of present and prospective water management procedures of medium-sized watersheds (1000 km2 an average) required close cooperation of hydrologists, hydrogeologists, and agricultural scientists. Development of stochastic methods in hydrology, even improvement of well known classical methods in the last years was triggered by such water management problems. Six of the "Rahmenplane" are already published by water administration agencies of some federal states. A few of these more used methods should be mentioned: - method of interpretation of fluctuation of the piezometric surface of an aquifer, - method of average monthly minimum runoffs (MoMNQ after WUNDT and other authors), - method of determination of underflow (Au-method after NATERMANN as graphical interpretation of hydrographs).