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Christoph J. Kuells

Christoph J. Kuells
University of Applied Sciences, Lübeck, Germany · Civil Engineering, Laboratory for Hydrology and International Water Management

Dr. Dipl. Hydr.

About

77
Publications
9,810
Reads
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1,075
Citations
Introduction
Hydrologist with a background in hydrogeology and geochemistry specialized and interested in water resources assessment, water quality studies and integration of solute cycles with the hydrological cycle. Working experience in the Eastern Mediterranean (Greece, Cyprus, Israel, Jordan), in Sub-Saharan and Central/Eastern Africa (South Africa, Namibia, Burundi, Rwanda) and in South-America (Brazil). I am trying to develop applied research involving SMEs and producing results for the 'real world'.
Additional affiliations
January 2007 - December 2012
University of Freiburg
March 1996 - September 2000
University of Wuerzburg
Position
  • Project Manager
Description
  • DFG Geowissenschaftliche Gemeinschaftsforschung in Afrika, Stipendiat im Graduiertenkolleg, EU Projekt GREM Groundwater Recharge in the Eastern Mediterranean, Projektkoordination
Education
March 1997 - December 2000
University of Wuerzburg
Field of study
  • Hydrogeology, Geology, Geomorphology
October 1988 - October 1994
Albert Ludwigs University Freiburg, Institute of Hydrology
Field of study
  • Hydrology

Publications

Publications (77)
Article
Full-text available
Quantifying evapotranspiration and drainage losses is essential for improving irrigation efficiency. The FAO-56 is the most popular method for computing crop evapotranspiration. There is, however, a need for locally derived crop coefficients (Kc) with a high temporal resolution to reduce errors in the water balance. The aim of this paper is to intr...
Article
Full-text available
The origin of groundwater recharge and subsequent flow paths are often difficult to establish in fractured, multi-lithological, and highly compartmentalized aquifers such as the Troodos Fractured Aquifer (TFA). As the conjunctive use of stable isotopes and hydrogeochemical data provides additional information, we established a monitoring network fo...
Article
Full-text available
Reliable information on water flow dynamics and water losses via irrigation on irrigated agricultural fields is important to improve water management strategies. We investigated the effect of season (wet season and dry season), irrigation management (flooded and non-flooded), and crop diversification (wet rice, dry rice, and maize) on soil water fl...
Article
Full-text available
Reliable information on water flow dynamics and water losses via irrigation on irrigated agricultural fields is important to improve water management strategies. We investigated the effect of season (wet season and dry season), irrigation management (flooded and non-flooded), and crop diversification (wet rice, dry rice, and maize) on soil water fl...
Article
Full-text available
The wide-range applications of isotope analysis make isotope measurement approaches under attentive focus. Off-axis integrated cavity output spectroscopy technology (OA-ICOS) is the most advanced isotope analysis method; however, further studies are still needed to avoid signal noise and improve accuracy. Zero-phase low pass filtering multivariate...
Article
Ophiolites often form complex, fractured, multi-lithological and highly compartmentalized aquifers that are difficult to characterize. Groundwater chemistry reflects water-rock interactions and can provide insights to groundwater recharge mechanisms, flow paths and relative residence time. A comprehensive hydrogeochemical modelling approach with PH...
Article
Full-text available
Reliable information on water flow dynamics and water losses via irrigation on irrigated agricultural fields is important to advance water management strategies. We investigated the effect of season (wet season, dry season), irrigation management (flooded, non-flooded), and crop diversification (wet rice, dry rice, and maize) on soil water dynamics...
Poster
Full-text available
This study proposes a multi-source data approach to estimating annual rates of floodwater recharge into the lower alluvial Andarax aquifer. The Andarax River catchment is about 2200 Km2, and although it is permanent in the upper part of the basin, the middle and lower catchment is ephemeral. The climate is Mediterranean with an annual average tempe...
Article
Full-text available
The short-term dynamics of carbon and water fluxes across the soil–plant–atmosphere continuum are still not fully understood. One important constraint is the lack of methodologies that enable simultaneous measurements of soil CO2 concentration and respective isotopic composition at a high temporal resolution for longer periods of time. δ¹³C of soil...
Article
Full-text available
The short-term dynamics of carbon and water fluxes across the soil–plant–atmosphere continuum are still not fully understood. One important constraint is the lack of methodologies that enable simultaneous measurements of soil CO2 concentration and its isotopic composition at a high temporal resolution for longer periods of time. δ¹³C of soil CO2 ca...
Conference Paper
Full-text available
Stable Isotopes of water are powerful proxies for the description of water fluxes such as infiltration, evapotranspiration and plant water uptake in a natural water resource system. Especially the measurement of soil pore water provides information on soil hydraulic properties and interactions within the soil-plant-atmosphere-interface. To gather s...
Article
An analytical Excel-based toolkit called Gas-Tracer-Interpretation (GTI) was developed for determining mean residence time (MRT) of groundwater samples and for validating conceptual model assumptions. This novel data interpretation toolkit improves data handling during analysis and resolves some problems in the interpretation of data from environme...
Conference Paper
Full-text available
The development of uranium mining in the arid Erongo region of central western Namibia has increased pressure on limited water resources. An assessment of available water resources and demand from different stakeholders was carried out. An Integrated Geohydrological Model (IGHMS) was developed. IGHMS produces time series of key hydrological process...
Article
Full-text available
A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water-content and on the chemica...
Conference Paper
Full-text available
Eco-hydrology is a recently emerging discipline combining the realms of water and ecology and exploring the interactions between ecosystems and hydrological processes. In few areas this close interaction is more pronounced, visible and decisive than in desert restoration. The degradation of drylands leads to a decline in ecosystem functioning and e...
Conference Paper
Full-text available
Since atmospheric tritium levels have neru·ly reached the nantral background, there is a need for fmther development of existing or additional methods for the age dating of young water. Non-gaseous age dating tracers ru·e especially needed for hydrological applications in lakes, livers and springs and for surface- groundwater interaction studies...
Article
Full-text available
The mechanisms allowing the rapid release of stored water to streams are poorly understood. Here we use a tile-drained field site to combine macroporous soils at the hillslope scale with the advantage of at least partly controlled lower boundary conditions. We performed a series of three irrigation experiments combining hydrometric measurements wit...
Article
Full-text available
The mechanisms allowing the rapid release of stored water to streams are poorly understood. Here we use a tile drained field site to combine naturally structured soils at the hillslope scale with the advantage of at least partly controlled lower boundary conditions. We performed a series of three irrigation experiments combining hydrometric measure...
Article
Full-text available
Predicting and understanding subsurface flowpaths is still a crucial issue in hydrological research. We present an experimental approach to reveal present and past subsurface flowpaths of water in the unsaturated and saturated zone. Two hillslopes in a humid mountainous catchment have been investigated. The H<sub>2</sub>O<sub>(liquid)</sub> – H<sub...
Article
Full-text available
Predicting and understanding subsurface flowpaths is still a crucial issue in hydrological research. We present an experimental approach to reveal present and past subsurface flowpaths of water in the unsaturated and saturated zone. Two hillslopes in a humid moutainous catchment have been investigated. The H<sub>2</sub>O<sub>(liquid)</sub> – H<sub>...
Article
Age dating of water based on dissolved CFCs and Krypton-85 has been applied extensively for many years. CFCs were adopted as an approach for water dating due to the availability of global input functions and because of a straightforward methodology. In the last decade, due to international treaties, CFCs production and atmospheric concentrations of...
Article
This paper summarises innovative research into the assessment of long-term groundwater recharge from flood events in dryland environments of the Kuiseb (Namibia) and the Buffels (South Africa) rivers. The integrated water resource management (IWRM) policies and institutions affecting the exploitation of groundwater resources in each of these develo...
Article
The isotopic composition of precipitation and melt-water lakes in Svalbard was studied. The IAEA precipitation record of monthly precipitation data from Ny Alesund reveals a much stronger and regular seasonal variability of deuterium excess compared to oxygen-18 and deuterium. The seasonal amplitude of deuterium excess in Ny Alesund is more pronoun...
Chapter
System approachDefinition of tracersModelling in the context of integrated tracerhydrologyFields of application
Chapter
GroundwaterCase studies in the unsaturated zone and in soilsSurface waterGlaciersCatchment scale
Chapter
Plate 1, 2Plate 3aPlate 3b-dPlate 4aPlate 4bPlate 4cPlate 5 and 6Plate 5aPlate 5bPlate 5cPlate 6aPlate 6bPlate 6cPlate 7Plate 7aPlate 7bPlate 8aPlate 8bPlate 8c
Chapter
Fluorescent tracersSalt tracersDrifting particles as tracersRadioactive tracersOther tracers
Chapter
Planning and execution of a tracer studyEstimation of tracer injection massGauging dischargeChloride method for groundwater recharge estimationHydrograph separation using the end member mixing analysis (EMMA)
Article
Flood water infiltrates ephemeral channels, recharging local and regional aquifers, and it is the main water source in hyperarid regions. Quantitative estimations of these resources are limited by the scarcity of data from such regions. The floods of the Kuiseb River in the Namib Desert have been monitored for 46 years, providing a unique data set...
Article
With few exceptions, only limited hydrologic data are available in regions with the highest scarcity of water. Especially in basins with limited data on hydrogeological structure, it is difficult to accurately characterize groundwater flow systems and their recharge sources. Therefore, estimation of available water resources in drylands requires me...
Article
Full-text available
In arid and semi-arid regions alluvial groundwater resources of ephemeral streams are highly important for water supplies and ecosystems. Recent projects have studied processes of indirect recharge in situ and in detail (Dahan et al., 2008; Klaus et al., 2008). Still, little is known about the vulnerability of these aquifers to environmental impact...
Article
CFCs (11, 12, 113) and SF6 have been used for age dating of recent groundwater (
Article
The representation of hydrological processes and biogeochemical feedbacks in common soil-vegetation-atmosphere-schemes constrains their response and adaptation to climate change impacts. A comparative study and review of SVAT schemes commonly used for the evaluation of climate change impacts shows that they differ significantly in emphasizing diffe...
Article
A mixing cell approach was extended by a method incorporating mean cell residence times derived from 14C to further constrain and validate the modeling results. This extended approach was used to model the groundwater system of the Lower Kuiseb Dune area in Namibia. The Kuiseb river is a 560 km long ephemeral river that crosses the Namib Desert fro...
Article
A study on flood water infiltration and ground water recharge of a shallow alluvial aquifer was conducted in the hyperarid section of the Kuiseb River, Namibia. The study site was selected to represent a typical desert ephemeral river. An instrumental setup allowed, for the first time, continuous monitoring of infiltration during a flood event thro...
Article
Full-text available
Multidisciplinary research in the hyperarid Kuiseb River, Namibia provides the necessary information to determine (a) long-term floods occurrence and aquifer recharge events and (b) flood routing and transmission processes along the river course. Together they assist in estimating water resources along the river. The only source of water along the...
Article
A study on flood water infiltration and ground water recharge of a shallow alluvial aquifer was conducted in the hyperarid section of the Kuiseb River, Namibia. The study site was selected to represent a typical desert ephemeral river. An instrumental setup allowed, for the first time, continuous monitoring of infiltration during a flood event thro...
Article
Full-text available
Groundwater recharge studies in semi-arid areas are fundamental because groundwater is often the only water resource of importance. This paper describes the water balance method of groundwater recharge estimation in three different hydro-climatic environments in eastern Mediterranean, in northwest Greece (Aliakmonas basin/Koromilia basin), in Cypru...
Article
Full-text available
Jordan is classified as an arid to semi-arid country with a population according to 1999 estimates of 4·8 millions inhabitants and a growth rate of 3·4%. Efficient use of Jordan's scarce water is becoming increasingly important as the urban population grows. This study was carried out within the framework of the joint European Research project ‘Gro...
Article
Full-text available
While Integrated Natural Resources Management (INRM) creates a need for an integration of natural and socio-economic information, suitable approaches and tools are needed to facilitate this integration. If these tools are meant to support the decision-making process of the stakeholders, it is important that they are adapted to the needs and require...
Conference Paper
TRÖGER, U., DIAS, C.L.; GUILLAUMON, J.R.; IRITANI, M.A.; KÜLLS, C.; SCHULER, G. 2004. Remarks and new data about the recharge of the Guarani Aquifer System. In: IAH, IAH Congress, 34, Proceedings, Zacatecas, México.
Article
The WAVES program (Water Availability, Vulnerability of Ecosystems and Society in Northeastern Brazil) aims at creating a knowledge base and strategies for sustainable development for the drought-prone northeast of Brazil. The perspective of climate change in a semiarid area with marginal water supplies requires strategic measures in order to avoid...
Article
Full-text available
A quantitative model of groundwater flows contributing to the Goblenz state water scheme at the north-western fringe of the Kalahari was developed within this study. The investigated area corresponds to the Upper Omatako basin and encompasses an outer mountainous rim and sediments of the Kalahari sand desert in the centre. This study revealed the e...
Chapter
One aim of the WAVES program (http://www.usf.uni-kassel.de/waves) was to identify sustainable development paths for Ceará and Piauí, two states in the semi-arid northeast of Brazil. In these states, regional development is negatively influenced by the high seasonality of rainfall and El-Niño-related drought years. The research focused on the interr...
Chapter
Full-text available
Only a spatially distributed approach can sufficiently describe recharge distribution in a large catchment. In this study the decreasing chloride concentration along groundwater flow paths has been used to represent recharge areas within the groundwater basin. Absolute recharge values, derived by application of the chloride balance method in the sa...
Chapter
Full-text available
An inverse hydrochemical mixing cell modelling approach has been used for the assessment of water resources in the Otjozondjupa region at the western fringe of the Kalahari basin, Namibia. The analysis is based on hydrochemical data from 1530 wells in the Omatako basin. Cluster analysis applied to a hydrochemical database was used to define, subdiv...
Article
Drought behaviour was investigated using standard methods of the theory of runs, which describe the duration and the deficit volume (severity) of a low flow event. The threshold chosen as Q90 produces zero elements. These zero elements are a problem for common fitting procedures. For the generalized extreme value distribution two estimation methods...
Chapter
Full-text available
For the estimation of transmission losses in an ephemeral stream, two infiltration tests were conducted in the dry channel. The advance of the wetting front was monitored with resistance plates. The hydraulic parameters for two infiltration models were derived using inverse estimation methods. Additionally dye tracer was used to investigate flow pa...

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Projects

Projects (5)
Project
Special Issue "Advances on the Dynamics of Groundwater Salinization" Groundwater salinization (GWS) is a global phenomenon of increasing interest due to its adverse effects on the socioeconomic structure and the physical environment. Being a complex phenomenon, it includes several inter-linked aspects of spatiotemporal resolution that are yet not fully understood or identified. We invite contributions that address scientific advances in temporal variations across all time scales and spatial coverages or even combined spatial-temporal dynamics. Experimental data, projections, and reconstructions are needed to show variations of salinization at short time scales to years, decades, or even at historical or paleo-hydrological scope by using residence time analysis combined with salinization indicators or modelling techniques. Paradigms of receding salinization trends due to remediation or management actions can also be highlighted to show the dynamics of salinization reversal. Contributions may also include various methodological approaches, such as geophysics, geochemistry, environmental isotopes, multivariate statistics, geostatistics, artificial intelligence, remote sensing, and in situ multi-parameter monitoring. Papers on high-resolution temporal variations of salinization in response to tidal effects, pumping, or changing external driving forces are welcome in order to improve our understanding around salinization dynamics. Contributions on spatial dynamics are also welcome and may include the extent and changes of transition zones between salt and fresh water or the detailed mapping of the extent and spatial-temporal evolution of groundwater salinization zones. More information can be found on: https://www.mdpi.com/journal/water/special_issues/dynamics_salinization
Project
Groundwater salinization in the Mediterranean is a phenomenon of increasing relevance and a focus area of subsurface water quality studies. Still, several recent reviews of the topic have identified that there still is a lack of studies addressing the temporal variations and spatial variations in groundwater and salinization in coastal aquifers in three dimensions. The session aims at exploring the dynamics of groundwater salinization. We invite contributions addressing temporal variations at all time scales and spatial or even combined spatial-temporal dynamics. Experimental data, projections, and reconstructions are needed showing variations of salinization at different time scales, from seasonal to historical and paleo-hydrological, e.g., by using residence time analysis combined with salinization indicators or modeling techniques. Hopefully, examples of receding salinization trends due to remed