The World Karst Aquifer Mapping project: concept, mapping procedure and map of Europe

Zhao Chen,Andrea Richts,Guanghui Jiang,Augusto S Auler,Franziska Griger,Nils Moosdorf,Zoran Stevanovic,Jens Hartmann,Michel Bakalowicz,David Drew,George Veni,Nico Goldscheider

doi:10.1007/s10040-016-1519-3

Abstract

Karst aquifers contribute substantially to freshwater supplies in many regions of the world, but are vulnerable to contamination and difficult to manage because of their unique hydrogeological characteristics. Many karst systems are hydraulically connected over wide areas and require transboundary exploration, protection and management. In order to obtain a better global overview of karst aquifers, to create a basis for sustainable international water-resources management, and to increase the awareness in the public and among decision makers, the World Karst Aquifer Mapping (WOKAM) project was established. The goal is to create a world map and database of karst aquifers, as a further development of earlier maps. This paper presents the basic concepts and the detailed mapping procedure, using France as an example to illustrate the step-by-step workflow, which includes generalization, differentiation of continuous and discontinuous carbonate and evaporite rock areas, and the identification of non-exposed karst aquifers. The map also shows selected caves and karst springs, which are collected in an associated global database. The draft karst aquifer map of Europe shows that 21.6% of the European land surface is characterized by the presence of (continuous or discontinuous) carbonate rocks; about 13.8% of the land surface is carbonate rock outcrop.

Highlights

According to an often-cited estimation by Ford and Williams (2007), approximately 20–25% of the global population depends largely or entirely on groundwater obtained from karst aquifers
Some areas contain many tiny, scattered or ramified carbonate rock polygons that cannot be displayed individually on the generalized map; the mapping unit Bdiscontinuous^ was introduced. By testing this approach in several regions, it turned out that the limits of 15 and 65% result in a meaningful generalization, both scientifically and in terms of graphical presentation; areas with more than 65% of carbonate rock were mapped as Bcontinuous,^ whereas areas between 15 and 65% were mapped as Bdiscontinuous.^ because of the heterogeneity of the underlying database, and due to the diversity and complexity of different geological provinces, this general rule had to be adapted individually during the process of manual generalization, while consulting available geological and hydrogeological literature for the respective regions
For the preparation of a world karst aquifer map, the available information was insufficient; a systematic global database on springs and other karst water sources was established in the framework of the World Karst Aquifer Mapping (WOKAM) project

Summary

Introduction

According to an often-cited estimation by Ford and Williams (2007), approximately 20–25% of the global population depends largely or entirely on groundwater obtained from karst aquifers. Some areas contain many tiny, scattered or ramified carbonate rock polygons that cannot be displayed individually on the generalized map; the mapping unit Bdiscontinuous^ was introduced By testing this approach in several regions, it turned out that the limits of 15 and 65% result in a meaningful generalization, both scientifically and in terms of graphical presentation; areas with more than 65% of carbonate (or evaporite) rock were mapped as Bcontinuous,^ whereas areas between 15 and 65% were mapped as Bdiscontinuous.^ because of the heterogeneity of the underlying database, and due to the diversity and complexity of different geological provinces, this general rule had to be adapted individually during the process of manual generalization, while consulting available geological and hydrogeological literature for the respective regions. For the preparation of a world karst aquifer map, the available information was insufficient; a systematic global database on springs and other karst water sources was established in the framework of the WOKAM project. Several books (e.g. Palmer and Palmer 2009; Courbon 1989; Laumanns 2002) and Internet resources (Gulden 2016)

Clot d’Aspres cave system

Findings

Conclusions