Vol. 149, No. 2-3 · Editorial Hydrogeography – linking water resources and their management DIE ERDE to physical and anthropogenic Journal of the Geographical Society catchment processes of Berlin Daniel Karthe1,2, Peter Chifflard3, Thomas Büche4,5 1 Environmental Engineering Section, German-Mongolian Institute for Resources and Technology, 2nd khoroo, Nalaikh District, Ulaanbaatar, Mongolia, [email protected] 2 Department Aquatic Ecosystem Analysis and Management, Helmholtz Centre for Environmental Research, Brückstr. 3a, 39114 Magdeburg, Germany 3 Faculty of Geography, Philipps-University, Deutschhausstr. 10, 35032 Marburg, Germany, [email protected] 4 Department of Geography, Ludwig-Maximilian University, Luisenstr. 37, 80333 München, Germany, [email protected] 5 now at WipflerPLAN Planungsgesellschaft mbH, Hohenwarter Straße 124, 85276 Pfaffenhofen, Germany 1. Introduction to the thematic issue This thematic issue was initiated by the working group on hydrology within the German Geographical The sufficient availability and quality of water is a Association (for details,th see http://www.ak-hydrologie.- prerequisite not only for all forms of plant, animal and de) ahead of its 50 anniversary meeting in 2018, and human life, but also for socioeconomic development,- (followsChifflard up on Kartheseveral 2014;other Cyffkathematic issues Karthe (co-)or 2013; with particularly strong links to the agricultural,- Kartheganized by the workingSun group in the past few years mining and industrial sectors. As one of the most fun and and damental sub-disciplines of geography, hydrogeogra Geographica et al. 2017; Augustanaet al. 2018).. The working group phy does not only describe the uneven distribution of also publishes annual conference proceedings in the water resources at the regional and global scale, but series also seeks to explain such differences on the basis of 2. State of the Art the physical environment and human interferences with nature. Hydrogeography (in contrast to a purely- physical hydrology) has therefore turned into a truly- geographical science – considering the complexWinkler in 2.1 Hydrology in the geographical perspective - 1970;terlinkages Uhlig between the physical and the human en - vironment – more than half a century ago ( Both at the global and regional scale, hydrologyCrutzen is in 1971). Hydrogeography continuesCommis to be- fluenced by physical and anthropogenic drivers. How- siona highly for Waterrelevant Sustainability geographical subdiscipline, as is for ever, in the era of the Anthropocene ( 2002), example evidenced by the existence of the Interna- the distinctions between ‘natural’ and ‘anthropogen- tional Geographical Union. (for details, please see ic’ processes have become less clear, because human- https://iguwater.wordpress.com) within the influences are now manifested in all parts of the natu ral environment. Global change “is marked by the in Daniel Karthe, Peter Chifflard, Thomas Büche 2018: Hydrogeography – linking water resources and their management to physical and anthropogenic catchment processes. – DIE ERDE 149 (2-3): 57-63 DOI:10.12854/erde-2018-412 DIE ERDE · Vol. 149 · 2-3/2018 57 Hydrogeography – linking water resources and their management to physical and anthropogenic catchment processes - (terdependenceGermer of physical, biogeochemical, economic, 2.2 Water quality and river ecology in the geographi social, cultural, demographic and political processes”- cal perspective et al. 2011: 1). In this context, water plays a prominent role in two ways: on the one hand, signifi- In a hydro-ecological perspective, riparian floodplains cant shifts in global and regional water distribution are an integral part of river systems, despite the fact are expected; on the other hand, various earthSteffen sys that their environment may seem more terrestrial tems (e.g. climates, soils, vegetation) are connected than aquatic, except for flood periods. The state of by oceanic currents and hydrologicalInternational flows ( As- river and riparian ecosystems is shaped not only sociationet al. 2005), of Hydrologicaland are thus Sciencesaffected (byIAHS the changes. It by natural hydrology, hydromorphology and water is therefore not surprising that the quality, but also by many other external effects. ) underlines the importance of interdisciplinary research efforts From a hydrogeographical perspective, it is important (inMontanari the context of 2013). the scientific decade “Panta Rhei – to understand that hydrology, water quality and river Everything flows: changes in hydrology and society” ecology are closely interlinked. For example, water et al. quality in a river depends not only on the amount of pollutant influx, but also on its hydrology (i.e. Historical hydrology reconstructs past river courses (itsChalov dilution capacity)Völker and ecological state (i.e. the or specific discharge events based on different types functioning of biogeochemical filtration mechanisms) of evidence, such as sediment records, historical et al. 2017; et al. 2013). Despite all documents on meteorological conditions, river basin progress in agricultural, mining, industrial and conditions and flood Deutschevents, photographs,Ruiz-Bellet official municipal water management,Karthe a good chemical statusUNEP documents,Roggenkamp news reports, personalHerget accounts and local 2016;of rivers Völker remains a challenge in many parts of the historians’ research ( et al. 2010; world, including Germany ( et al. 2017; et al. 2015; and 2014, 2016). et al. 2013). In mining regions throughout the world, water,Winde sediment and soilThorslund pollution are often Hydrology investigates water flows both on the particularly problematic, even after mining activities (surfaceRogger and below the surface, often looking at the have ceased ( et al. 2004; et al. 2012). scale of river catchments or meaningful subunits - et al. 2017). The different flow pathways The ecological assessment of water bodies requires the are governed by various drivers which include (a) monitoring not only of hydrological, hydro-morphologiBorchardt the characteristics of a precipitationChifflard event, (b) the cal andRichter physico-chemical water quality parameters, but Hortonhydraulic properties of subsurface layers (soils and also function-oriented biological indicators ( - underlying rock formations) ( et al. 2018a; and 2003). Because aquatic ecosystems depend 1933) and (c) surface cover propertiesGermer such as on functioning riparianAishan ecosystems,Stammel the ecological res 2010;vegetation Pistocchi or artificial surface sealing, including any toration of floodplains has received increasing attention- anthropogenic modifications thereof ( et al. in recent years ( Tomscha et al. 2015; et al. 2016), et al. 2015). in particular regarding the provision of regulating eco system services ( et al. 2017). Today, the majority of the world’s large rivers are dammed in at least some sections. Dams, no matterHauer for which purpose they are erected, do not only 2.3 Water management and hydro-geography - modify the temporalHahn pattern of Mackdischarge ( et al. 2016), but also affect physico-chemicalChalov waterWohl In the context of efficient water usage and manage- characteristicsRathburn ( et al. 2016; et al. 2013), ment, hydrogeography turns into a more applied and- sediment transportVörösmarty regimes ( et al. 2016; solution-oriented science. Maximizing water use effi and 2003) and the connectivity of river ciency is a prominentKarthe goal for water managers in dry- systems ( et al. 2010). Moreover, in dry land regions such as the continental parts of Central regions, dams lead to significantBarbier evaporation 2006). losses and Eastern Asia ( 2018). Very important wa which may result in the evaporation of half the storage ter users in this region include agriculture,Feike and other volume during a single year ( 2015;forms Guoof vegetation such as trees planted for erosion control, in oasis or for urban greening ( et al. 58 et al. 2016). DIE ERDE · Vol. 149 · 2-3/2018 Hydrogeography – linking water resources and their management to physical and anthropogenic catchment processes - - Because many major riversBoklan cross internationalJanusz-Pawletta bor one of the key factors of surface runoff generation ders, river basin management often requires a trans due to its high spatial and temporal variability. A self- boundary perspective ( and - constructed rainfall simulator is used to compare 2017). In such cases, a common understanding about- the runoff generation of four horse and cattle grazed water managementVölker goals is essential, as it is practical pastures, respectively, with different antecedent soil ly exemplified by the EuropeanHeldt Water Framework Di moisture but homogeneous geological underground rective ( et al. 2013) which is being considered a and soil types. The experimental approach reveals reference even outside the EU ( et al. 2017). distinctively higher runoff coefficients for sites grazed by horses than by cattle and confirms the Despite all (justified) criticism of purely technocratic strong importanceChristian of the Reinhardt-Imjela, antecedent soil Katja moisture. Maerker, approaches, water management in the anthropocene Achim Schulte Arno Kleber also requires the development and implementation The paper by of water-related technologies. Wastewater treatment and investigates the role is a point in case: while water quality in many rivers- that periglacial cover beds play for near-surface water