Author Correction: Global karst springs hydrograph dataset for research and management of the world's fastest-flowing groundwater.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Global karst springs hydrograph dataset for research and management of the world's fastest-flowing groundwater.

Karst aquifers provide drinking water for 10% of the world's population, support agriculture, groundwater-dependent activities, and ecosystems. These aquifers are characterised by complex groundwater-flow systems, hence, they are extremely vulnerable and protecting them requires an in-depth understanding of the systems. Poor data accessibility has limited advances in karst research and realistic representation of karst processes in large-scale hydrological studies.

Comprehensive micropollutant screening using LC-HRMS/MS at three riverbank filtration sites to assess natural attenuation and potential implications for human health.

Riverbank filtration (RBF) is used worldwide to produce high quality drinking water. With river water often contaminated by micropollutants (MPs) from various sources, this study addresses the occurrence and fate of such MPs at three different RBF sites with oxic alluvial sediments and short travel times to the drinking water well down to hours. A broad range of MPs with various physico-chemical properties were analysed with detection limits in the low ng L range using solid phase extraction followed by liquid chromatography coupled to tandem high resolution mass spectrometry.

Combining monitoring and modelling tools as a basis for city-scale concepts for a sustainable thermal management of urban groundwater resources.

Increasing anthropogenic impacts lead to elevated temperatures of the shallow subsurface, including the unsaturated and groundwater saturated zone, in many urban areas in comparison to unaffected natural thermal states. The "current thermal state" of four groundwater bodies in the urban area of Basel-City, Switzerland, was investigated by means of high-resolution multilevel temperature wells and numerical 3D groundwater flow and heat transport models. The calibrated and validated numerical groundwater flow and heat transport models allow evaluating and comparing groundwater and heat fluxes for the investigated groundwater bodies and defined cross-sections for differing urban districts, e.

Process-based monitoring and modeling of Karst springs - Linking intrinsic to specific vulnerability.

The presented work illustrates to what extent field investigations as well as monitoring and modeling approaches are necessary to understand the high discharge dynamics and vulnerability of Karst springs. In complex settings the application of 3D geological models is essential for evaluating the vulnerability of Karst systems. They allow deriving information on catchment characteristics, as the geometry of aquifers and aquitards as well as their displacements along faults.

Spatiotemporal scales of river-groundwater interaction - The role of local interaction processes and regional groundwater regimes.

Drinking water production in the vicinity of rivers not only requires the consideration of different spatiotemporal scales and settings of river-groundwater interaction processes, but also of local and regional scale groundwater regimes. Selected case studies in combination with field-experiments and the setup of high-resolution groundwater flow models enabled the investigation of the spatiotemporal development of microbial (classical fecal indicator bacteria and total cell counts) and selected organic micropollutants in riverine and regional groundwater for different hydrological settings, including low and high flow conditions. Proxy indicators suitable as surrogates for the diverse contaminations in alluvial aquifers with different settings could be identified.

Online analysis: Deeper insights into water quality dynamics in spring water.

We have studied the dynamics of water quality in three karst springs taking advantage of new technological developments that enable high-resolution measurements of bacterial load (total cell concentration: TCC) as well as online measurements of abiotic parameters. We developed a novel data analysis approach, using self-organizing maps and non-linear projection methods, to approximate the TCC dynamics using the multivariate data sets of abiotic parameter time-series, thus providing a method that could be implemented in an online water quality management system for water suppliers. The (TCC) data, obtained over several months, provided a good basis to study the microbiological dynamics in detail.

The thermal impact of subsurface building structures on urban groundwater resources - A paradigmatic example.

Shallow subsurface thermal regimes in urban areas are increasingly impacted by anthropogenic activities, which include infrastructure development like underground traffic lines as well as industrial and residential subsurface buildings. In combination with the progressive use of shallow geothermal energy systems, this results in the so-called subsurface urban heat island effect. This article emphasizes the importance of considering the thermal impact of subsurface structures, which commonly is underestimated due to missing information and of reliable subsurface temperature data.

Online flow cytometry reveals microbial dynamics influenced by concurrent natural and operational events in groundwater used for drinking water treatment.

Detailed measurements of physical, chemical and biological dynamics in groundwater are key to understanding the important processes in place and their influence on water quality - particularly when used for drinking water. Measuring temporal bacterial dynamics at high frequency is challenging due to the limitations in automation of sampling and detection of the conventional, cultivation-based microbial methods. In this study, fully automated online flow cytometry was applied in a groundwater system for the first time in order to monitor microbial dynamics in a groundwater extraction well.

On the effects of subsurface parameters on evaporite dissolution (Switzerland).

Uncontrolled subsurface evaporite dissolution could lead to hazards such as land subsidence. Observed subsidences in a study area of Northwestern Switzerland were mainly due to subsurface dissolution (subrosion) of evaporites such as halite and gypsum. A set of 2D density driven flow simulations were evaluated along 1000 m long and 150 m deep 2D cross sections within the study area that is characterized by tectonic horst and graben structures.

Validation of a numerical indicator of microbial contamination for karst springs.

Rapid changes in spring water quality in karst areas due to rapid recharge of bacterially contaminated water are a major concern for drinking water suppliers and users. The main objective of this study was to use field experiments with fecal indicators to verify the vulnerability of a karst spring to pathogens, as determined by using a numerical modeling approach. The groundwater modeling was based on linear storage models that can be used to simulate karst water flow.

Enhanced vulnerability assessment in karst areas by combining mapping with modeling approaches.

The objective of this work is to facilitate a sustainable regional planning of water resources in karst areas by providing a conceptual framework for an integrative vulnerability assessment. A combined mapping and modeling approach is proposed, taking into account both spatial and temporal aspects of karst groundwater vulnerability. The conceptual framework comprises the delineation of recharge areas, vulnerability mapping, numerical flow and transport modeling and the integration of information into a combined vulnerability map and time series.