Committee on Groundwater Hydraulics and Management
Scope
Groundwater hydraulics covers the flow of water
in aquifers and involves, more generally, the flow and transport
processes in porous media. Water management and the environment
are main topics of concern. Groundwater is part of the hydrological
cycle and represents a complex ecosystem which needs a multidisciplinary
understanding. Groundwater constitutes the most available freshwater
resource of the earth, as much as two orders of magnitude larger
than the total water volume of rivers and lakes. Because it is less
prone to pollution than surface waters, it is most important as
a drinking water resource.
Groundwater systems vary greatly, depending on the geological formation
of the aquifer (sand and gravel aquifers, fissured rock aquifers,
karstic aquifers). Their hydraulics are characterised by large water
bodies, very small flow velocities and hence extremely long exchange
times. Transport at the regional scales is affected by local heterogeneities
of the geological formations, and is governed by advection and molecular
diffusion at pore/grain size scale. Chemical reactions of pollutants
and bacterial life take place at the pore/grain size scale. Groundwater
is recharged by rainfall, when it percolates through the unsaturated
zone to the aquifers, and by infiltration of surface water. Across
its open boundaries, groundwater can be polluted by local sources
of accidentally released contaminants or by pollutants released
from diffusely distributed sources like agricultural activities.
Groundwater contamination has developed into one of the key environmental
issues in most industrialised countries. Industrial contamination
sources include waste sites, leakage, accidental spills and leaking
septic tanks. Liquid contaminants (e.g., oil products or halegonated
hydrocarbons), which are not miscible with the water can exist underground
(in the unsaturated and in the saturated zones) as non-aqueous phase
as well as dissolved in the water, adsorbed at the solid phase,
and mixed in the soil-air. In such cases the subsoil is a multi-phase
system. Agricultural contamination sources are fertilisers and the
use of herbicides and pesticides. Air pollution contributes by depositing
contaminants that make their way into the groundwater.
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Research
Agenda
Groundwater management: Acute problems for groundwater management are overexploitation,
lowering of groundwater tables, water deficits , and water pollution.
The evaluation and development of sustainable water resources systems
remain important topics in groundwater management. Improved land
use management, needed to increase recharge by reducing runoff and
evaporation, is currently being studied especially in arid climates.
Further problems result from land subsidence caused by overexploitation
of groundwater resources. In coastal areas, problems of salt water
intrusion are important. Furthermore, groundwater can be used to
store and retrieve heat for cooling and heating. However any groundwater
management activity has to be based on an adequate description and
thorough prospecting. Improved methods have to be developed.
Groundwater monitoring: Monitoring
groundwater quantity and quality: Careful monitoring of aquifers,
including estimates of discharges in groundwater flows and storage,
can allow early recognition of chemical spills and biological activities
and enhance timely countermeasures. Remote sensing methods, using
new sensors like radar, are being developed for estimates of the
soil water balance.
Groundwater remediation: A re-establishment
of groundwater quality of polluted aquifers requires the clean-up
of contamination in the saturated and the unsaturated zones. The
mechanisms of multiphase flow, and the transport, mixing and mass
transfer in the multiphase system ”subsurface” are not
sufficiently understood and the efficiency of different clean-up
techniques is difficult to assess. Therefore, there is a need for
basic work concerning the understanding and the mathematical description
of the processes, as well as applied research concerning the developed
and improvement of remediation techniques and the construction of
effective hydraulic barriers for polluted sites.
Political decisions on land use: Groundwater is often considered as a secondary issue in decisions
regarding land use in highly populated and industrialised countries.
However, the issue of groundwater protection has to establish its
value among the conflicting interests of infrastructure, industry
and agriculture.
Risk and uncertainty analysis in the decision-making
process for sustainable development: The risk of groundwater
pollution is ubiquitous, and it is often characterised by extremely
long remediation and recovery times. Improved assessment of the
vulnerability of groundwater resources is critically important.
Underground space use: Caused by
an increased demand for the use of underground space for construction,
the development of suitable geotechnical techniques that ensure
both quantity and quality of the adjacent groundwater is needed.
Unsaturated Zone: The zone of groundwater
table fluctuations is characterised by frequent changes between
saturated and unsaturated conditions. Of particular significance
are areas such as flood plains or wetlands. Within the unsaturated
zone, air is present as a third phase, leading to aerobic processes.
It can form an important barrier that prevents pollutants from entering
the groundwater. Although models of transport and reaction in the
upper soil layer have been developed, they are not sophisticated
enough to be able to predict with confidence the impact of new agricultural
practices on the watershed. Improper irrigation can cause salination
problems. Direct effects of changes in groundwater tables upon vegetation
and the terrestrial ecosystem can be observed and should be better
understood.
Exchange with surface water: Groundwater
is related to the surface terrestrial and aquatic ecosystems in
many ways. The directions of the fluxes of water and pollutants
vary with the levels of surface water and groundwater, depending
on hydrological conditions. These fluxes are controlled by the state
of the river bed or lake bottom, which can be clogged by filtering,
biological growth or previous chemical reactions. Alternatively
these areas can be cleared by a flood with the consequence that
pollutants stored in the sediment are released. This interface is
a crucial zone where processes like absorption and decay of pollutants
need further study.
Coupled flow, transport and bio-geo-chemical
processes: In order to model non-conservative contaminant
transport, it is essential to couple chemical and biochemical phenomena
with flow and transport models. The approach taken by chemists and
biologists is to understand the microscopic reactions (redox reaction,
sorption, precipitation, biodegradation). The kinetics of the reactions
can be controlled either by the actual thermodynamic reaction or
by the transport mechanism in the porous media which bring the reactants
into contact with one another. It is therefore essential to understand
the exact coupling of flow and transport and of bio-geo-chemistry.
Aquifers as bacterial ecosystems are poorly described. More effort
is needed to understand the dependence of the nature and abundance
of bacteria upon factors like temperature, water movement, distribution
of organic matter, chemical composition and physical properties
of the aquifer. The interaction of these micro-organisms with the
chemistry of the groundwater has to be further studied.
Upscaling: The rules and laws that
can be used to upscale flow and pollutant transport still need to
be further developed, both in terms of the constituent equations
and the relevant parameters which have to be measured in the field.
Spatial variability of flow and transport parameters and bio-geochemical
properties in natural media can be very large. Major multidisciplinary
field experiments have to be carried out to study this upscaling.
Mathematical modelling: The purpose
of mathematical models is not only to provide instruments to forecast
or estimate processes in a real system, but also to relate sub-processes
and concepts, e.g., found in laboratory, and to transfer concepts
from one system to another. Stochastic approaches are needed to
describe the heterogeneity of the aquifers and to develop parameter
estimation methods which allow the models to be calibrated against
field observations. These issues are addressed by estimating the
variance of the predictions or by conditioning based on measured
values. Therefore, adequate models should be formulated.
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Committee Officers
Leadership Team
Chair
 |
Prof. Xavi Sanchez-Vila
Department of Geotechnical Engineering and Geosciences
Universitat Politecnica de Catalunya, Barcelona, Spain
Email: xavier.sanchez-vila@upc.edu |
Vice Chair
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Prof. Alberto Guadagnini
Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento (D.I.I.A.R.)
Politecnico di Milano, Italy
E-mail: alberto.guadagnini@polimi.it |
Past Chair
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Prof. Nadim Copty
Institute of Environmental Sciences
Bogazici University
34342 Bebek
Istanbul, TURKEY
phone: +90 212 359 1540
fax: +90 212 257 50 33
e-mail: ncopty@boun.edu.tr |
Members
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Prof. Yoram Rubin
Department of Civil Engineering
University of California
Berkeley, CA 94720, USA
e-mail: rubin@ce.berkeley.edu |
 |
Prof. Philippe Renard
Centre of Hydrogeology and Geothermics (CHYN)
Institute of Geology and Hydrogeology
University of Neuchâtel
CH - 2009 Neuchâtel, Switzerland
E-mail: philippe.renard@unine.ch |
 |
Prof. Sabine Attinger
Department Computational Hydrosystems,
Helmholtz Center for Environmental Research, Leipzig, Germany
Institute of Geosciences, Friedrich Schiller University Jena , Germany
E-mail: sabine.attinger@ufz.de |
 |
Prof. Yangwen Jia
Department of Water Resources
China Institute of Water Resources & Hydropower Research (IWHR)
Beijing 100038, China
E-mail: jiayw@iwhr.com
|
Co-opted members
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Prof. Jaime Gomez
Universidad Politécnica de Valencia
Departamento de Ingeniería Hidráulica y Medio Ambiente
Grupo de Hidrogeología
46022 Valencia, Spain
Email: jgomez@upv.es |
 |
Prof. Rachid Ababou
Institut de Mécanique des Fluides de Toulouse
Alleé du Professeur Camille Soula
F-31400 Toulouse, France
E-mail: ababou@imft.fr |
 |
Prof. Lakshmi Narasimharao
Dept. of Geology
S.V. University
Tirupati – 517 502, India
E-mail: doctor_rao@hotmail.com |
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Publications
- Journal of Hydraulic Research, Vol 42(extra issue), 2004, Groundwater: ”Bridging the gap between measurements and modelling”, Special issue with selected papers from the IAHR International Groundwater Symposium held at Lawrence Livermore Laboratory, Berkeley, USA March 2002
- Proceedings of the International Groundwater Symposium: “Bridging the gap between measurements and modeling”, held at Lawrence Livermore Laboratory, Berkeley, CA USA, Co-sponsored by IAHR, IAHS, EWRI and AGU, Published by IAHR, ISBN: 90-805649-4-X, March 2002,
- Journal of Hydraulic Research Vol 36, Issue 6 (Special Issue), 1998
- Int. Symposium on Interaction between Groundwater
and Surface Water, Ystad, Sweden, May 30-June 3, 1988. Ed. P.
Dahlblom and G. Lindh. 550 pages, 3 volumes. From Dept. of Water
Resources
Engineering, Lund University, Box 118, S-22100 Lund, Sweden.
- Int. Symposium on Contaminant Transport in Groundwater,
Stuttgart, Germany, April 4-6, 1989. Members: NLG 184,-; Non-members:
NLG 225,-. From A.A. Balkema Publishers
- Int. Symposium on Transport and Reactive Processes
in Aquifers, Zurich, April 11-15, 1994, Th. Dracos and F. Stauffer.
Members NLG 156,-; non-members NLG 195,-. From A.A. Balkema Publishers.
- Int. Conference on Analytic Based Modelling of
Groundwater Flow, Nunspeet, The Netherlands, April 7-11, 1997.
From Conference Secr., Analytic Based Modelling of Groundwater
Flow, Buerweg 51, 1861 CH Bergen, The Netherlands
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Reports
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