Emerging organic contaminants in groundwater: A review of sources, fate and occurrence

http://www.vliz.be/imisdocs/publications/242609.pdf

Seawater intrusion processes, investigation and management: Recent advances and future challenges

The Prediction in Ungauged Basins (PUB) initiative of the International Association of Hydrological Sciences (IAHS), launched in 2003 and concluded by the PUB Symposium 2012 held in Delft (23–25 October 2012), set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as well as associated uncertainties and the development of models with increasing realism and predictive power. This paper reviews the work that has been done under the six science themes of the PUB Decade and outlines the challenges ahead for the hydrological sciences community.Editor D. KoutsoyiannisCitation Hrachowitz, M., Savenije, H.H.G., Bloschl, G., McDonnell, J.J., Sivapalan, M., Pomeroy, J.W., Arheimer, B., Blume, T., Clark, M.P., Ehret, U., Fenicia, F., Freer, J.E., Gelfan, A., Gupta, H.V., Hughes, D.A., Hut, R.W., Montanari, A., Pande, S., Tetzlaff, D., Troch, P.A., Uhlenbrook, S., Wagener, T., Winsemius, H.C., Woods, R.A., Zehe, E., and Cudennec, C., 2013. A d...

/pdf/a-decade-of-predictions-in-ungauged-basins-pub-a-review-2g78unzpne.pdf

A decade of Predictions in Ungauged Basins (PUB)—a review

Karst aquifers have complex and original characteristics which make them very different from other aquifers: high heterogeneity created and organised by groundwater flow; large voids, high flow velocities up to several hundreds of m/h, high flow rate springs up to some tens of m3/s. Different conceptual models, known from the literature, attempt to take into account all these particularities. The study methods used in classical hydrogeology—bore hole, pumping test and distributed models—are generally invalid and unsuccessful in karst aquifers, because the results cannot be extended to the whole aquifer nor to some parts, as is done in non-karst aquifers. Presently, karst hydrogeologists use a specific investigation methodology (described here), which is comparable to that used in surface hydrology. Important points remain unsolved. Some of them are related to fundamental aspects such as the void structure – only a conduit network, or a conduit network plus a porous matrix –, the functioning – threshold effects and non-linearities –, the modeling of the functioning – double or triple porosity, or viscous flow in conduits – and of karst genesis. Some other points deal with practical aspects, such as the assessment of aquifer storage capacity or vulnerability, or the prediction of the location of highly productive zones.

Karst groundwater: a challenge for new resources

https://pubag.nal.usda.gov/download/7446/PDF

A review and evaluation of catchment transit time modeling

On the theory of tracer experiments in fissured rocks with a porous matrix

Preface. Acknowledgements. 1 Introduction. 2 The Integrated Concept of Tracers in Hydrology. 2.1 System approach. 2.2 Definition of tracers. 2.3 Modelling in the context of integrated tracerhydrology. 2.4 Fields of application. 3 Environmental Tracers. 3.1 Introduction. 3.2 Stable isotopes of water. 3.3 Stable isotopes in soil. 3.4 Stable isotopes in surface and groundwater. 3.5 The use of environmental isotopes for hydrological system analysis. 3.6 Nitrogen isotopes and origin assignment. 3.7 Age dating. 4 Artificial Tracers. 4.1 Fluorescent tracers. 4.2 Salt tracers. 4.3 Drifting particles as tracers. 4.4 Radioactive tracers. 4.5 Other tracers. 5 Mathematical Modelling of Experimental Data. 5.1 Artificial tracer (ideal) under saturated flow conditions. 5.2 Tracer experiments under unsaturated flow conditions. 5.3 Tracer experiments in streams and rivers. 5.4 Environmental tracer data. 5.5 The goodness-of-fit of a model. 6 Technical Instructions. 6.1 Planning and execution of a tracer study. 6.2 Estimation of tracer injection mass. 6.3 Gauging discharge. 6.4 Chloride method for groundwater recharge estimation. 6.5 Hydrograph separation using the end member mixing analysis (EMMA). 7 Case Studies. 7.1 Groundwater. 7.2 Case studies in the unsaturated zone and in soils. 7.3 Surface water. 7.4 Glaciers. 7.5 Catchment scale. Colour Plate Section. References. Index.

Tracers in Hydrology

Application of flow models in an alpine catchment area using tritium and deuterium data

[1] The spatial and temporal (event and seasonal timescale) variability of major runoff components in the mountainous Brugga basin (Black Forest, Germany) were examined. The mesoscale (40 km2) study basin represented an extraordinary challenge as comparable studies have been undertaken mainly in smaller headwater basins. Discharge data, tracer concentrations of 18O, 3H, CFCs, and dissolved silica, and major anions and cations were analyzed during single events and over a period of 3 years. Three main runoff components were defined: event water with a residence time of several hours to a few days contributed up to 50% during flood peaks, quantified by a classical hydrograph separation technique using 18O. However, this component is of minor importance for longer periods, comprising ∼11.1% of total runoff as estimated for the period August 1995 to April 1998. The other two flow components originated from shallow and deep groundwater. Source areas for these are the upper drift and debris cover for the shallow groundwater and the deeper drift, weathering zone and hard rock aquifer for the deep groundwater. Mean residence times ranged from 28 to 36 months on the basis of 18O data for the shallow groundwater and from 6 to 9 years on the basis of 3H and CFC data for the deep groundwater. The importance of the upper drift and debris cover of the slopes for runoff generation at the test site was clearly demonstrated at the seasonal timescale, showing a contribution of 69.4% based on a mixing model with a monthly time step. The deep groundwater contribution was 19.5%. With this information a conceptual model of runoff generation for the study site was constructed.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2001WR000938

Hydrograph separations in a mesoscale mountainous basin at event and seasonal timescales

Several published tracer tests are reexamined using the single fracture dispersion model (SFDM), i.e., a solution to the transport equation in which fractured rock is represented by a single fracture and the tracer is allowed to diffuse into the matrix. The model has three fitting parameters, i.e., the mean time of flow, dispersivity, and a diffusion parameter which combines such physical parameters as matrix porosity, coefficient of matrix diffusion, and adjusted fracture aperture. The model is easily calibrated yielding as good, or better, fits as did the models applied in original works, which were based on an assumption of negligible matrix diffusion and were characterized by larger numbers of fitting parameters. The SFDM better describes the short-term transport in investigated systems and/or their parameters than models applied so far. Validation of the model was obtained by showing that the values of its physical parameters either agree with those known from other methods or are within expected ranges. Another validation was achieved for tests performed in the same pair of wells with two tracers characterized by distinctly different coefficients of molecular diffusion. In spite of distinct differences in the shapes of the experimental curves, the SFDM yielded the same values of the fracture aperture, matrix porosity, and intrinsic dispersivity. The ratio of the diffusion coefficients in the matrix was close to that known from the diffusion coefficients in free water.

Piotr Maloszewski

Papers

On the theory of tracer experiments in fissured rocks with a porous matrix

Tracers in Hydrology

Application of flow models in an alpine catchment area using tritium and deuterium data

Hydrograph separations in a mesoscale mountainous basin at event and seasonal timescales

Tracer experiments in fractured rocks: Matrix diffusion and the validity of models