Table Of ContentDISTRIBUTED HYDROLOGICAL MODELLING
Water Science and Technology Library
VOLUME 22
Editor-in-Chie!
V. P. Singh, Louisiana State University,
Baton Rouge, U.S.A.
Editorial Advisory Board
M. Anderson, Bristol, U.K.
L. Bengtsson, Lund, Sweden
A. G. Bobba, Burlington, Ontario, Canada
S. Chandra, New Delhi, India.
M. Fiorentino, Potenza, Italy
W. H. Hager, Zurich, Switzerland
N. Harmancioglu, Ivnir, Turkey
A. R. Rao, West La!ayette, Indiana, U.S.A.
M. M. Sherif, Giza, Egypt
Shan Xu Wang, Wuhan, Hubei, P.R. China
D. Stephenson, Johannesburg, South Africa
The titles published in this series are listed at the end of this volume.
DISTRIBUTED
HYDROLOGICAL
MODELLING
edited by
MICHAEL B. ABBOTT
International Institute/or InJrastructural,
Hydraulic and Environmental Engineering,
Delft, The Netherlands
and
JENS CHRISTIAN REFSGAARD
Danish Hydraulic Institute,
Hf/Jrsholm, Denmark
KLUWER ACADEMIC PUBLISHERS
DORDRECHT / BOSTON / LONDON
Library of Congress Cataloging-in-Publication Data
Distributed hydrological modelling I edited by Michael B. Abbott and
~ens Christian Refsgaard.
p. cm. -- (Water science and technology library; v. 22)
Inc 1u des index.
ISBN-13: 978-94-010-6599-3 (hb : ac i d-free paper)
1. Hydrology--Mathematical models. I. Abbott. Michael B.
II. Refsgaard. ~ens Christian. III. Series.
GB656.2.M33D57 1996
551.48·01·5118--dc20 96-14534
ISBN-13: 978-94-010-6599-3 e-ISBN-13: 978-94-009-0257-2
DOl: 10.1007/978-94-009-0257-2
Published by Kluwer Academic Publishers,
P.O. Box 17, 3300 AA Dordrecht, The Netherlands.
Kluwer Academic Publishers incorporates
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D. Reidel, Martinus Nijhoff, Dr W. Junk and MTP Press.
Sold and distributed in the U.S.A. and Canada
by Kluwer Academic Publishers,
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In all other countries, sold and distributed
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Printed on acid-free paper
All Rights Reserved
© 1996 Kluwer Academic Publishers
No part of the material protected by this copyright notice may be reproduced or
utilized in any form or by any means, electronic or mechanical,
including photocopying, recording or by any information storage and
retrieval system, without written permission from the copyright owner.
Softcover reprint of the hardcover 1st edition 1996
Table of Contents
Foreword vii
Chapter 1. The Role of Distributed Hydrological Modelling in Water Resources
Management / J.C. REFSGAARD and M.B. ABBOTI
Chapter 2. Terminology, Modelling Protocol and Classification of Hydrolog-ical
Model Codes / J.C. REFSGAARD 17
Chapter 3. Construction, Calibration and Validation of Hydrological Models/ J.e.
REFSGAARD and B. STORM 41
Chapter 4. Distributed Physically-based Modelling of the Entire Land Phase of
the Hydrological Cycle / B. STORM and A. REFSGAARD 55
Chapter 5. Multi-species Reactive Transport Modelling / PETER ENGES6AARD 71
Chapter 6. Soil Erosion Modelling / J.K. L0RUP and M. STYCZEN 93
Chapter 7. Agrochemical Modelling / M. THORSEN, 1. FEYEN and M. STYCZEN 121
Chapter 8. Weather Radar Precipitation Data and Their Use in Hydrological
Modelling / C.G. COLLIER 143
Chapter 9. Application of Remote Sensing for Hydrological Modelling / F.P. DE
TROCR, P.A. TROCR, Z. SU and D.S. LIN 165
Chapter 10. Geological Modelling / M. HANSEN and P. GRAVESEN 193
Chapter 11. Use of GIS and Database with Distributed Modelling / F. DECKERS
and e.B.M. TE STROET 215
Chapter 12. An Engineering Case Study - Modelling the Influences of Gab
cikovo Hydropower Plant on the Hydrology and Ecology in the Slovakian Part
of the River Branch System of Zitny Ostrov / R.R. S0RENSEN, J. KLUCOVSKA,
J. TOPOLSKA, T. CLAUSEN and J.e. REFSGAARD 233
Chapter 13a. A Discussion of Distributed Hydrological Modelling / K. J. BEVEN 255
Chapter 13b. Comment on 'A Discussion of Distributed Hydrological Modelling'
by K. Beven / J.C. REFSGAARD, B. STORM and M.B. ABBOTT 279
Chapter 13c. Response to Comments on 'A Discussion of Distributed Hydrolog-
ical Modelling' by J.e. Refsgaard et al. / K. J. BEVEN 289
Chapter 14. Hydrological Modelling in a Hydroinformatics Context! A.W. MINNS
and V. BABOVIC 297
Index 313
DISTRIBUTED HYDROLOGICAL MODELLING
Foreword
It is the task of the engineer, as of any other professional person, to do everything that
is reasonably possible to analyse the difficulties with which his or her client is
confronted, and on this basis to design solutions and implement these in practice. The
distributed hydrological model is, correspondingly, the means for doing everything that
is reasonably possible - of mobilising as much data and testing it with as much
knowledge as is economically feasible - for the purpose of analysing problems and of
designing and implementing remedial measures in the case of difficulties arising within
the hydrological cycle. Thus the aim of distributed hydrologic modelling is to make the
fullest use of cartographic data, of geological data, of satellite data, of stream discharge
measurements, of borehole data, of observations of crops and other vegetation, of
historical records of floods and droughts, and indeed of everything else that has ever
been recorded or remembered, and then to apply to this everything that is known about
meteorology, plant physiology, soil physics, hydrogeology, sediment transport and
everything else that is relevant within this context. Of course, no matter how much data
we have and no matter how much we know, it will never be enough to treat some
problems and some situations, but still we can aim in this way to do the best that we
possibly can.
Now why should we need a model for this purpose; why, in particular, should we need
a distributed model? The answer lies in our proviso of 'what we possibly can'. For we
experience our outer world as being itself distributed in space and proceeding in time
and we collect our data accordingly, while a large part of our knowledge is about how
the quantities which enter our data change in space and time, both of themselves and
in relation to one another. Thus, in order to comprehend this outer world we need a
representation that is distributed, if only conceptually, in space, and which proceeds in
time, with processes described correspondingly. Correspondingly again, our analyses,
designs and remedial measures must also be described in a spatially-distributed and
time-dependept way, and the need for economy of means and of thought then neces
sitate that this representation must be one that is expressed in terms of signs, and then,
in our present time, of signs that are acceptable to a digital machine. Since these sign
representations must then provide us with other, higher-order signs, which point the
way to our analyses, our designs and our remedial measures, these must constitute
vii
viii
models. Thus the spatially-distributed and time-dependent model becomes the conditio
sine qua non for investigations in this area.
Given this position of distributed hydrological models, the question naturally arises of
why they are so rarely applied to anything like their full potential to the multifarious
problems of the hydrologic environment. The number and depth of applications appears
to be quite out of proportion to the manifest needs for the results that these systems
alone can provide. Of course, any number of reasons are adduced by organisations and
individuals for this situation - 'insufficient data', 'insufficient knowledge of processes',
'unnecessary complication' , and any number of others -but these have long since been
exposed as being, for the most part, only surrogates for quite other kinds of difficulties.
Some two decades of experience in the application of such systems has shown that the
'scientific' and 'technical' reasons that are presented are in fact surrogates for
difficulties which have an institutional-political, administrative and, in a word, social
origin. Modelling, as all integral part of hydro informatics generally, is a sociotechnical
activity, and the difficulties that confront distributed hydrological modelling arise
primarily from the social (institutional and administrative) side. They are primarily
functions of institutional and administrative structures, organisations and modes of
collaboration.
An analysis of the many institutional setbacks experienced in the application of
distributed models has shown a clear pattern in this direction and has allowed us to
understand more clearly the origins of these reverses. Expressed in a nutshell: the
distributed model puts demands upon the availability of data and of knowledge in
hydrology that singularly few organisations alone are currently capable of supplying.
Alongside this, and compounding its negative influences, there are few institutional
arrangements in place for correcting this situation through a cooperation between
organisations for the supply of hydrological data and knowledge. Thus, when seen by
an individual or a group of persons situated within these organisations, it really does
appear as though 'there is not enough data' and 'there is insufficient knowledge of
processes'. Similarly, the application of a deterministic model must appear as an
'unnecessary inconvenience' when it appears to necessitate changes, both within the
organisation itself and in its collaborative arrangements. But, of course, in a world of
increasing commercial pressures on most organisations, few of these like to admit that
it is they that do not have enough data or it is their organisations that cannot mobilise
enough knowledge, so that they raise the spectre of insufficient data or insufficient
knowledge or whatever else of this kind as a scientific or technical problem in its own
right. The fact is then conveniently ignored that if anything is to be done at all - a
reservoir to be extended, soil to restored after a chemical spill, a waste dump to be
removed, a new water extraction policy to be introduced, etc, etc, - the distributed
ix
model will nearly always narrow down the range of uncertainty in the outcome of the
intervention, and that, whatever the data and knowledge that is available, this represents
the best that we can do for a given level of investment in data and knowledge. If we
add to this the common observation that such studies point towards the most cost
effective means to reduce the range of uncertainty for a given extra investment in data
and knowledge, the utility of such models is further emphasised.
Given this situation, the solution to the problem of encouraging the wider application
of distributed hydrologic models must be sought in the experience of sociotechilology.
This shows clearly that most problems that appear as 'social' can be overcome by the
proper production and social employment of technical means. Thus the question
concerning the future of this class of models devolves upon the question of elaborating
an appropriate strategy of technological development, proceeding both on the side of
the technology itself and on the si.de of its application in society. This, in its tum,
directs attention to the encapsulation of distributed hydrologic models into such
productions of hydro informatics as real-time control, diagnostic and other model-based
systems and decision-support environments. On one side (the 'input' side) this leads to
means to encapsulate other data and knowledge than the hydrological and to combine
and merge this in the (adaptive) objects of the systems and environments, and on the
other side (the 'output' side) it leads to the further integration of the associated models
with geographical information systems and other such standard tools of control and
management practice. As this technology has now been rather thoroughly researched
and applied in surrounding areas, such as for the real-time control of urban drainage
systems and for the management of coastal-aquatic environments, the task of carrying
it over to hydrologic applications is proving less onerous than would otherwise be the
case. As the first such systems come to maturity, it is expected that distributed
hydrologic modelling will emerge from the institutional-social impasse that has so long
constrained it, so that it will finally come to attain to its full stature.
M.B. Abbott
J.e. Refsgaard
CHAPTER 1
THE ROLE OF DISTRIBUTED HYDROLOGICAL MODELLING IN WATER
RESOURCES~AGEMENT
J.C. REFSGAARD1 AND M.B. ABBOTT2
Danish Hydraulic Institute, Hnrsholm, Denmark
1
International Institute for Injrastructural, Hydraulic and Environmental
2
Engineering, Delft, The Netherlands
1. Problems in Water Resources Management
"Scarcity and misuse of fresh water pose a serious and growing threat to sustainable development and
protection of the environment. Human health and welfare, food security, industrial development and the
ecosystems on which they depend, are all at risk, unless water and land resources are managed more
effectively in the present decade and beyond than they have been in the past". (lCWE, 1992)
The present status and the future challenges facing hydrologists and water resources
managers are summarized in this way in the introductory paragraph of the Dublin
Statement on Water and Sustainable Development (lCWE, 1992). The Dublin Statement
was adopted by government-designated experts from 114 countries and representatives
of 80 international, intergovernmental and non-governmental organizations at the
International Conference on Water and the Environment (a preparatory conference for
the UNCED conference held in Rio de Janeiro in June 1992).
Since the ancient civilizations of Persia, Egypt and Babylon some 4000 years ago,
water resources and water supply technology have played foundational roles in the
development and organisation of many societies.
However, rapid population growth and the industrial development during the past
few decades have caused an increasing pressure on land and water resources in almost
all regions of the world. Due to increasing demands for water for domestic,
agricultural, industrial, recreational and other uses and due to an increasing pollution
of surface and groundwater, water resources have become scarce natural resources.
The availability of good-quality water is critical for human survival, economic
development and the environment. Yet, water resources are not being managed in an
efficient and sustainable manner. At the ICWE and UNCED conferences focus was put
on past experiences of water resources management and new principles outlining
improved future approaches were agreed upon. The World Bank in a follow-up policy
paper (World Bank, 1993) emphasizes three problems which in particular need to be
addressed:
* Fragmented public investment programming and sector management, that have failed
to take account of the interdependencies among agencies, jurisdictions, and sectors
* Excessive reliance on overextended government agencies that have neglected the
M. B. Abbott and J. C. Refsgaard (eds.). Distributed Hydrological Modelling, 1-16.
© 1996 Kluwer Aeademic Publishers.
2 J. C. REFSGAARD AND M. B. ABBOTI
need for economic pricing, financial accountability, and user participation and have
not provided services effectively to the poor
* Public investments and regulations that have neglected water quality, health and
environmental concerns.
Central elements in the World Bank's new policy are adoption of a comprehensive
policy framework and the treatment of water as an economic good, combined with
decentralized management and delivery structures, greater reliance on pricing, and
fuller participation of stakeholders.
Such new approach to water resources management requires, first of all, combined
efforts of professionals from a large range of disciplines such as economists,
administrators, engineers, hydrologists and ecologists, as well as a cross-sectoral
integration in the planning and management process. As the traditions for cooperation
and integration among these various disciplines and sectors have generally not been very
strong, this challenge is very large and crucial.
Additionally, the increased water resources problems and the new managetp.ent
approach require improved water resources management tools based on sound scientific
principles and efficient technologies. Key characteristics of such improved technologies
are that they to a larger extent than the existing tools must facilitate a holistic view of
water resources as well as cooperation among different disciplines and sectors involved
in water resources management. This involves, amongst others, an integrated
description of the entire land phase of the hydrological cycle, an integrated description
of water quantity, quality and ecology, and integration of hydrological, ecological,
economical and administrative information in information systems specifically designed
for decisions makers at different levels.
The role of distributed hydrological models should be seen in this context. As will
be described later in this chapter and in other chapters of this book distributed
hydrological models are essential elements comprising some of these required
capabilities. Hence, distributed hydrological models are important and necessary, but
far from sufficient, tools in improving the future water resources management.
In Section 2 of this chapter a brief review is made of important present problems and
trends related to water resources. Section 3 provides a review of the state-of-the-art in
hydrological modelling aiming to assist in the analysis and management of these
problems.
Section 4 contains a discussion on which factors limit the practical use of distributed
hydrological modelling in water resources management.
2. Key Issues and Trends in Water Resources
2.1. EFFECTS OF EXPLOITATION OF WATER RESOURCES
In 1940 the total global water use was about 1,000 km3 per year. It had doubled by
1960 and doubled again by 1990 (Clarke, 1991). In most countries of the world there
is not enough readily available water of sufficient quality for another such doubling.
Developments in some countries, such as China and India, suggest that this may be
