Table Of ContentHYDROCLIMATE
The Influence of Water Movement on
Freshwater Ecology
HYDROCLIMATE
The Influence of Water
Movement on
Freshwater Ecology
IAN R. SMITH
Edinburgh, Scotland, UK
ELSEVIER APPLIED SCIENCE
LONDON and NEW YORK
ELSEVIER SCIENCE PUBLISHERS LTD
Crown House, Linton Road, Barking, Essex IGll 8JU, England
Sole distributor in the USA and Canada
ELSEVIER SCIENCE PUBLISHING CO., INC.
655 Avenue of the Americas, New York, NY 10010, USA
WITH 17 TABLES AND 135 ILLUSTRATIONS
© 1992 ELSEVIER SCIENCE PUBLISHERS LTD
British Library Cataloguing in Publication Data
Smith, Ian R.
Hydroclimate: the influence of water movement on freshwater ecology.
I. Title
574.52632
ISBN 1-85166-724-5
Library of Congress Cataloging-in-Publication Data
Smith, Ian R.
Hydroclimate: the influence of water movement on freshwater
ecology/Ian R. Smith.
p. cm.
Includes bibliographical reference and index.
ISBN 1-85166-724-5
1. Freshwater ecology. 2. Hydrometeorology. I. Title.
QH541.5.F7S65 1992 91-31565
574.5'2632--dc20 CIP
No responsibility is assumed by the Publisher for any injury and/or damage to persons
or property as a matter of products liability, negligence or otherwise, or from any use or
operation of any methods, products, instructions or ideas contained in the material
herein.
Special regulations for readers in the USA
This publication has been registered with the Copyright Clearance Centre Inc. (Ccq,
Salem, Massachusetts. Information can be obtained from the CCC about conditions
under which photocopies of parts of this publication may be made in the USA. All other
copyright questions, including photocopying outside the USA, should be referred to the
publisher.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, electronic, mechanical, photo
copying, recording, or otherwise, without the prior written permission of the publisher.
Preface
Sun, wind and water draining from the land interact with the
morphological features of a water body to create the environment
experienced by freshwater plants and animals. The result of this
interaction can be considered as the freshwater hydro climate and this
plays the same role as that of conventional climate in terrestrial
ecology. Agriculture, for example, has long been supported by
specialist meteorological services which not only provide farmers with
a sound interpretation of weather and climate without excessive
technicality but which also consider relations between climate and the
growth of crops and stock. There is a need for a similar service in
freshwater ecology and applied biology. This book is the result of a
number of years devoted to developing part of that service. It
concentrates on the influence of all forms of water movement on the
ecology of fresh waters.
Water movement implies interest in both the quantity of water
moving through river basins which reflects the climate of the catch
ment as well as the nature of the fluid motion within the rivers and
lakes of the basin. The book is not so much a review of recent research
as an attempt to establish a logic-how knowledge of water movement
can contribute to understanding the ecology of fresh waters. Two
points follow directly. One is the need for the book to be comprehen
sible to non-specialists and I hope this is achieved by emphasising
simple physical arguments despite the rather formidable list of
symbols. There is also the difficulty that, once you start discussing
freshwater ecology, when do you stop? The chapter on freshwater
ecosystems is, inevitably, over-simplified and the intention is simply to
provide a basis for assessing the influence of physical conditions. The
general theme, however, is that of stimulating ecologists to consider
v
vi Preface
the implications of the environmental features described than to
suggest that these are fully understood already. I am very conscious
that there is a gap between this account of some of the physical
features of rivers and lakes and the interests and activities of practising
ecologists. I hope this book will help to bridge that gap.
I hope the book will appeal to all with an interest in rivers and
lakes-undergraduates, graduate students and practising professionals
in both management and research. I also like to think that the book
will be of interest to naturalists. Understanding processes is always
satisfying and, to me, the motion of eddies in a river is just as
delightful as the flight of a dipper. Engineers and hydrologists may find
the account of the freshwater environment presents their own interests
in a new light and give them an insight into the ecological conse
quences of their activities.
I would like to thank Peter Maitland, Chris Gibson and Alan Steel.
All read parts of the book and made a number of helpful suggestions.
Above all, I would like to thank Alec Lyle who read the whole draft,
supplied most of the photographs and who, over the years, made
working with rivers and lakes such a pleasure. The responsibility for
the errors is, obviously, mine. I am also grateful to Ken Morris and
David Jones for allowing me to use their photographs.
IAN R. SMITH
18 Tarpin Road, Edinburgh, EH13 OHW, UK
Contents
Preface ..
v
Chapter 1 Hydroclimate . . . . . . . . . . . . . . . . . 1
Chapter 2 The structure and dynamics of river basins . 4
2.1 River basin structure . . . . . 4
2.1.1 Introduction . . . . . . . 4
2.1.2 Longitudinal river sections . 6
2.1.3 Catchment form . 8
2.1.4 River networks. . 12
2.2 Climate and streamflow 16
2.2.1 Runoff generation. 16
2.2.2 Climate classification 19
2.2.3 Average flow. . . . 22
2.2.4 Seasonal variation in flow 25
2.2.5 Discharge frequency. 26
2.2.6 Floods and low flows . . 31
Chapter 3 Outline of fluid dynamics . . 39
3.1 Basic features of fluid motion .. 40
3.1.1 Characteristics of fluid motion 40
3.1.2 Methods of analysis. 42
3.2 The nature of turbulence 43
3.2.1 Basic features . . . 43
3.2.2 Boundary layer flow. 48
3.2.3 Turbulent structure . 51
3.2.4 Advection-diffusion equation. 54
3.2.5 Free turbulence. . . . . . . 56
3.3 Hydrodynamic properties of particulate matter. 58
3.3.1 Introduction .. 58
3.3.2 Static properties . . 60
vii
viii Contents
3.3.3 Bed deposits . . . . . . . 62
3.3.4 Particles in suspension. . . 62
3.4 The dynamics of particulate matter. 64
3.4.1 Introduction . . . . . . . 64
3.4.2 The onset of bed movement 66
3.4.3 Particles in suspension. 67
3.4.4 Shields' diagram . 70
3.4.5 Cohesive sediments. . 72
Chapter 4 The dynamics of hydraulic systems 74
4.1 Linear systems theory. . . . . 74
4.1.1 Introduction . . . . . . . . 74
4.1.2 Response to standard inputs . 77
4.1.3 Mass balance of a mixed basin 79
4.2 Incomplete mixing . . . . . . 82
4.2.1 Mixing processes . . . . . 82
4.2.2 Residence time distributions 83
4.2.3 Reaction efficiency 87
4.3 Compartment models . 88
4.3.1 Introduction . . 88
4.3.2 Parallel systems. . 89
4.3.3 Series systems . . 91
4.3.4 Systems with backflow . 93
4.3.5 Seasonal stratification 95
4.4 Final remarks . . . . . . 97
Chapter 5 Hydraulic characteristics of rivers . 98
5.1 River morphology . . . . . . . . . 98
5.1.1 Introduction . . . . . . . . . . 98
5.1.2 Classification of river morphology. 98
5.1.3 Relations between channel dimensions and flow 101
5.1.4 Particle size variation along a river 108
5.1.5 Micro-topography of river beds. 111
5.2 River mechanics . . . . . . . . 113
5.2.1 River as a boundary layer flow. 113
5.2.2 Stage discharge curves. . . . . 123
5.2.3 Dissolved and suspended loads. 124
5.2.4 Numerical example . . . . . . 126
5.3 Hydrodynamic features of river habitats. 131
5.3.1 Introduction . . . . . . . . . . . 131
Contents ix
5.3.2 River stability 132
5.3.3 Micro-hydraulics 136
5.3.4 Dispersion and mixing in rivers . 139
Chapter 6 Hydraulic characteristics of lakes . 142
6.1 Lake morphology. 142
6.1.1 Introduction 142
6.1.2 Standard measures 142
6.1.3 Hydrodynamic measures. 146
6.2 Wind characteristics. 148
6.2.1 Introduction 148
6.2.2 Features of land station data . 150
6.2.3 Wind over water 151
6.3 The hydraulic structure of lakes 155
6.4 Wind-water interactions. 157
6.4.1 Basic processes . 157
6.4.2 Empirical observations. 158
6.4.3 Langmuir circulations . 159
6.4.4 Hydrostatic balance . 161
6.4.5 Vertical current structure 162
6.5 Motion in isothermal lakes. 163
6.5.1 Introduction 163
6.5.2 Two dimensional steady circulation 165
6.5.3 Circulation in irregularly shaped lakes . 167
6.5.4 Surface seiches . 169
6.6 Motion in stratified lakes 173
6.6.1 The occurrence of stratification . 173
6.6.2 Properties of a stratified profile . 176
6.6.3 Thermocline tilt and internal seiches 178
6.6.4 Regimes of stratified motion . 179
6.6.5 Steady state circulation in stratified lakes 183
6.7 Surface waves 183
6.7.1 Wave characteristics. 183
6.7.2 Deep water waves. 186
6.7.3 Shore zone waves . 189
6.8 Other features of lake motion 191
6.8.1 Inflow and outflow dynamics . 191
6.8.2 Turbulence in lakes . 195
6.8.3 Exchanges between sediment and water 199
6.9 Final remarks 202
x Contents
Chapter 7 River basin modification. . 204
7.1 Reservoirs and flow regulation . 204
7.1.1 Types of reservoir . 204
7.1.2 Storage theory . . . . . 206
7.1.3 Reservoir features. . . . 208
7.2 Modifications to river habitats 209
7.2.1 Introduction . . . . . . 209
7.2.2 Effects of flow changes . 210
7.2.3 Changes in river structure 211
Chapter 8 Freshwater Ecosystems . 215
8.1 Idealised ecosystems . . . . 215
8.1.1 Ecosystems and ecosystem models 215
8.1.2 Idealised river ecosystems 219
8.1.3 Idealised lake ecosystems 222
8.2 Rate controlled growth 224
8.2.1 Introduction 224
8.2.2 Resources . . 224
8.2.3 Regulators. . 226
8.2.4 Physical losses 228
8.2.5 General remarks 229
8.3 Event controlled growth. 229
8.3.1 The nature of events 230
8.3.2 Species response to events . 231
8.3.3 Hydrodynamic stress and population loss 234
8.3.4 Population loss due to a sudden discharge of toxin 235
8.4 Space controlled growth. . . . . . . . 237
8.4.1 Spatial variation in plankton growth. 237
8.4.2 Habitat availability 239
8.5 Final remarks 240
Chapter 9 Synthesis 242
9.1 Background . 242
9.1.1 Interests involved in river basins 242
9.1. 2 The logic of hydro dim ate investigations 244
9.1.3 Modelling aquatic systems 246
9.2 River models. . . . . . . 246
9.2.1 River description . . . 247
9.2.2 Transport and storage. 249
9.2.3 River ecology. . . . . 253
Contents xi
9.3 Lake models. . . . . . . . . 256
9.3.1 Introduction ...... . 256
9.3.2 Basic features of lake hydroclimate 256
9.3.3 Lake ecology. 259
References . 261
Appendix 1: The properties of water . 271
A.l Viscosity-temperature relationship. 271
A.2 Density-temperature relationship 271
Appendix 2: Notation 273
Index ... 279
