Unesco Representative and experimental basins.

Representative

and

experimental basins.

An international guide fou research and practice

Edited by C. Toebes and V. Ouryvaev

‘I

A contribution to the International Hydrological Decade

Unesco

Studies and reports in hydrology 4

TITLES IN THIS SERIES

Co-edit ion Unesco/IASH

The use of analog and digital computers in hydrology. Proceedings of the Tucson Symposium, vol. 2.

I

Water in the unsaturated zone. Proceedings of the Wageningen Symposium, vol. 1. / L’eau dans la zone non saturée. Actes du symposium de Wageningen, vol. 1.

Floods and their computation. Proceedings of the Leningrad Symposiurn, August 1967, vol. 2. J

Les crues et leur évaluation. Actes du symposiiim de Leningrad, aJût 1967, vol. 2.

i.

2.

3.

Published by Unesco

Representative and experimental basins

-

Discharge of selected rivers of the world, vol. 1. / Débit de certains cours d’eau du monde, vol. 1.

4.

5.

Published in 1970 by the United Nations Educational, Scientific and Cultural Organization Place de Fontenoy, 75 Parìs-P

Printed by Henkes-Holland, Haarlem

0 Unesco 1570 Prinled in îhe Neiherlands SC NS.68/XX-l/A

Preface

The International Hydrological Decade (IHD) 1965-74 was launched by the General Conference of Unesco at its thirteenth session to promote international co-operation in research and studies and the training of specialists and technicians in scientific hydrology. Its purpose is to enable all countries to make a fuller assessment of their water resources and a more rational use of them as man’s demands for water constantly increase in face of developments in population, industry and agriculture. In 1968, national committees for the Decade had been formed in iW- of Unesco’s 122 Member States to carry out national activities and to contribute to regional and international activities within the programme of the Decade. The implementation of the programme is supervised by a Co-ordinating Council, composed of twenty-one Member States selected by the General Conference of Unesco, which studies proposals for developments of the programme, recommends projects of interest to all or a large number of countries, assists in the development of national and regional projects and co-ordinates international co-operation.

Promotion of collaboration in developing hydrological research techniques, diffusing hydrological data and planning hydrological installations is a major feature of the programme of the IHD which encompasses all aspects of hydrological studies and research. Hydrological investigations are encouraged at the national, regional and international level to strengthen and to improve the use of natural resources from a local and a global perspective. The programme provides a means for countries well advanced in hydrological research to exchange scientific views and for developing countries to benefit from this exchange of information in elaborating research projects and in implementing recent developments in the planning of hydrological installations.

As part of Unesco’s contribution to the achievement of the objectives of the IHD the General Conference authorized the Director-General to collect, exchange and disseminate information concerning research on scientific hydrology and to facilitate

Preface

contacts between research workers in this field. To this end Unesco has initiated two collections of publications : Studies and Reports in Hydrology, and Technical Papers in Hydrology.

The collection Studies and Reports in Hydrology is aimed at recording data collected and the main results of hydrological studies undertaken within the framework of the Decade as well as providing information on research techniques. Also included in the collection will be proceedings of symposia. Thus, the collection will comprise the compilatibn of data, discussions of hydrological research techniques and findings, and guidance material for future scientific investigations. It is hoped that the volume will furnish material of both practical and theoretical interest to hydrologists and governments participating in the IHD and respond to the needs of technicians and scientists concerned with problems of water in all countries.

The responsibility for the choice and presentation of facts and for opinions and views expressed lies with the organizations and authors cited in the foreword to each publication in the collection.

The designations employed and the presentation of the material do not imply the expression of any opinion whatsoever on the part of Unesco concerning the legal status of any country or territory, or of its authorities, or concerning the delimitations of the frontiers of any country or territory.

Contents

Foreword

List of contributors

1 Introduction

1.1 1.2 1.2.1 1.2.2 1.3 1.3.1 1.3.2 1.4 1.4.1 1.4.2 1.4.3 1.4.4 I .5 1.6

Scope and purpose

Definition of representative and experimental basins Representative basins

Experimental basins Representative basins Experimental basins Survey of research needs

Staffing for basins

Basic recommendations on standardization of methods of observation, instrumentation and data processing

Data-reporting methods

Research co-operation and research observation programmes Purposes of representative and experimental basins

Terminology

Measurement units and symbols References

2 Selection and organization of basin networks

2.0 General

2.1 Use of maps

2.2 Selection of hydrological regions 2.2.1

2.2.1.1 Example in Brazil 2.2.1.2 Example in N e w Zealand 2.2.2

Selection of hydrological regions in arcas where no detailed hydrological data are available

Selection of hydrological regions in areas where detailed hydrological data 17 19

21 22 22 23 23 23 24 24 25 25 21 21 30 36 41

43 43 44 45 46 41

Contents

2.2.2. I 2.2.3 2.3 2.4 2.4.1 2.5

Example in the U.S.S.R.

Selection of representative basins Selection of experimental basins Analysis of a basin’s representativeness References

Delineation of soil-vegetation complexes

Selection of run-off plots

3 Planning of observations according to the research objectives

3.1 3.1.1 3.1.1.1 3.1.1.2

3.1.1.3 3.1.1.4 3.1.2 3.2 3.2.1 3.2.2 3.2.3 3.2.3.1 3.2.3.2 3.2.4 3.2.5 3.2.5.1 3.2.5.2 3.2.5.3 3.2.6 3.2.7 3.2.7.1 3.2.7.2 3.2.7.2. I 3.2.8 3.2.9 3.2.10 3.2.1 1 3.2.12 3.2.13 3.2.13.1 3.2.13.2 3.3 3.3.1 3.3.1.1 3.3.1.2

General

Observational programme for representative basins

Observational programme for representative basins used for fundamental research

Observational programme for representative basins used for the study of the effect, on the hydrological regimen, of natural changes (benchmark and vigil basins)

Observational programme for representative basins used for hydrological prediction

Observational programme for representative basins used for extension of records

Observational programme for experimental basins Precipitation

Interception Snow cover

Snow survey Snowmelt Condensation Evaporation

Observational asprcts of principal hydrological elements

Evaporation from the water surface Evapotranspiration

Evaporation from snow Surface water

Subsurface water

Water in the unsaturated zone Water in the saturated zone

Determination of principal characteristics of aquifers Infiltration

Glaciers

Erosion and sedimentation Quality of water

Ice phenomena in streams

Climatological data and energy balance Climatological observations

Measurement of energy-balance components

Planning observations for the study of the effect, on the hydrological regimen, of a natural and/or cultural change

The study of the influence of forest on the hydrological regimen Selection of basins

Programme of observations References

48 51 51 53 54 55 56

51 58 58

58 59 59 59 60 60 61 61 62 62 63 63 63 64 64 65 67 67 67 68 68 69 69 70 70 71 71 71 72 73 74 74 75

Contents

I ^{4 Methods of} observation and instrumentation

~ 4.1.1 4.' 4. I .1.1 4.1.1.2 4.2 4 2.1 4.2.1.1 4.2.1.2 4.2.1.2.1 4.2.1.3 4.2.1.3.1 4.2.1.3.2 4.2.1.3.3 4.2.1.3.4 4.2.1.3.5 4.2.1.3.6 4.2.2 4.2.2.1 4.2.3 4.2.3.1 4.2.3.1.1 4.2.3.1.1.1 4.2.3.1.1.2 4.2.3.1 .I .3

I I

4.2.3.1.2 4.2.3.1.2.1 4.2.3.1.2.2 4.2.3.1.2.4 4.2.3.2 4.2.3.3 4.2.3.4 4.2.4 4.2.4. I 4.2.4.2 4.2.4.2.1 4.2.4.2.1.1 4.2.4.2.1.2 4.2.4 2.1.4 4.2.4.2.1.5 4.2.4.2.1.6 4.2.4.2.1.7 4.2.4.2.1.8 4.2.4.2.1.9 4.2.4.2. I. 10 4.2.4.2.1.11 4.2.4.2.1.12 4.2.4.2.1.13 4.2.4.2.2 4.2.4.2.2.1 4.2.4.2.2.2 , 4.2.3.1.2.3

I

General requirements Sampling techniques

Sampling in time Sampling in space Climate

Precipitation General Networks

Precipitation gauges Network reappraisal Recording raingauges

Non-recording precipitation gauges Errors in precipitation gauges Installation methods

Selection of precipitation gauges Measurement of dew and fog Snow cover

Snowmelt

Interception of precipitation by vegetation Interception of rain

Forest vegetation General Variables

Methods and instrumentation

4.2.3.1.1.3.1 Gross rainfall, 91; 4.2.3.1.1.3.2 Throughfall, 91;

4.2.3.1.1.3.3 Stem flow, 91; 4.2.3.1.1.3.4 Litter interception, 91;

4.2.3.1.1.3.5 Sampling intensity, 91 Herbaceous vegetation

General

Sampling methods Gross interception loss Net interception loss Interception of snow Interception of dew and fog Future research

Evaporation pans

Evaporimeters and lysimeters Evaporimeters

Evaporation

General

Soil evaporimeter GGI-500-100 Soil evaporimeter GGI-500-50

The small-type hydraulic soil evaporimeter The big hydraulic evaporimeter (BGI) Forest hydraulic evaporimeter (large type) Soil-weighing evaporimeter

Soil-weighing evaporimeter (large) Evaporimeter for swamps GGI-B-1000 Lysimeter-compensating evaporimeter Soil raingauge

Methods of observation of evaporation from the soil surface Evaporation from snow

Lysimeters Purpose

Principle of construction

76 77 77 78 79 79 79 79 82 82 82 82 83 84 84 84 84 89 89 89 69 89 90 91

92 92 92 93 93 93 94 95 95 95 98 98 98 99 99 99 99 101 102 103 103 103 103 104 104 105 105 105

~~

Contents

4.2.4.2.2.4 4.2.4.2.2.5 4.2.4.2.2.6 4.2.5 4.2.5.1 4.2.5.2 4.2.5.2.1 4.2.5.2.1.1 4.2.5.2.1.2 4.2.5.2.2 4.2.5.3 4.3 4.3.1 4.3.2 4.3.2.1 4.3.2.2 4.3.3 4.3.4 4.3.4.1 4.3.4.2 4.3.4.3 4.3.4.4 4.3.4.5 4.3.4.5.1 4.3.5 4.3.5.1 4.3.5.2 4.3.5.2.1 4.3.5.2.2 4.3.5.2.2.1 4.3.5.2.3 4.3.5.2.3.1 4.3.5.3 4.3.5.3.1 4.3.5.3.2 4.3.5.3.3 4.3.5.3.4 4.3.5.3.5 4.3.5.3.6 4.3.5.3.1 4.3.6 4.3.6.1 4.3.6.2 4.3.6.3 4.3.6.4 4.3.6.5 4.3.6.6 4.3.7 4.3.1.1 4.3.1.2 4.3.1.3 4.3.7.4 4.3.1.5 4.3.7.6 4.3.1.1 4.3.1.8 4.3.1.9 4.3.7.9.1 4.3.7.9.2

The non-weighable lysimeter

Lysimeters of the U.S.S.R. Hydrometeorological Service Major disadvantage of the lysimeter

Other climatic observations, including energy balance Climate stations

Climate station requirements Instrumentation

Fully equipped base station Auxiliary climate station Location

Instrumentation and observational techniques Surface water

Objectives

Streams and gauging-site selection The stage-measurement cross-section The flow-measurement cross-section Natural controls (high flow-low flow)

Precalibrated devices-weirs, flumes and orifices Experimental basins

Representative basins

Desiderata for measuring structures Permanency of rating

Stage inaccuracies

Precalibrated artificial structures

Flow measurement-current meter, chemical, miscellaneous Current-meter limitations

Chemical-gauging methods Salt-velocity method Salt-dilution method Integration or ‘gulp’ method

Fluorescent dye-dilution method Use of dyes

Miscellaneous methods Head-rod method Slope-area method Volumetric gauging

Optical current-meter gauging Measurement of îlow through culverts

Measurement of flow through contracted openings Float measurements

Stage measurement Staff gauges

Automatic stage recording Float-recorder stations Punched-tape recorders Pressure-bulb recorders Servo-manometer Winter operation

Effect of ice on the stage discharge relation Freezing of stilling well

Summer or tropical operation Blockage of control

Float-recorder structures Intake pipes

Flushing

Accuracy requirements

Operation, maintenance and accuracy requirements of gauging stations

Accuracy of calibrated structures Accuracy of field-rated controls

~

108 108 109 1 o9 109 110 110 110 110 110 1 1 1 112 112 112 112 112 113 113 113 113 i 14 114 114 115 127 130 130 130 130 130 130 130 131 131 131 131 131 131 131 131 132 132 132 132 132 134 134 135 135 135 135 136 136 136 136 136 131 131 137

Contenis

4.3.8 4.4 4.4.1 4.4.1.1 4.4.1.1.1 4.4.1.1.2 4.4.1.1.2.1 4.4.1.1.2.2

4.4.1.1.3 4.4.1.1.4 4.4.2 4.4.2.1 4.4.2.2 4.4.2.2.1

~ 4.4.2.2.2 4.4.2.3 4.4.2.3.1 4.4.2.3.2 4.5 4.5.1 4.5.1.1 4.5.1.2 4.5.1.3 4.5.1.4 4.5.1.5 4.5.1.6 4.6 4.6.1 4.6.2 4.6.2.1 4.6.2.2 4.6.2.3 4.6.3 4.6.4 4.7 4.7.1 4.7.2 4.7.2.1 4.7.2.2 4.7.3 4.7.4 4.8 4.8.1 4.8.2 4.8.3 4.9 4.9.1 4.9.2 4.9.2.1 4.9.2.1.1 4.9.2.1.2 4.9.2.1.3 4.9.2.2 4.9.2.2.1 4.9.2.2.1.1 4.9.2.2.1.2

Run-off plots 137

Subsurface water 140

Water in the unsaturated zone 140

Soil moisture 140

Networks 141

Measurement methods and equipment 142

Electrical resistance units 142

Neutron-scattering technique 143

4.4.1.1.2.2.1 Access tubing, 143; 4.4.1.1.2.2.2 Measurement site, 143;

4.4.1.1.2.2.3 Calibration, 143 Frequency of measurement Laboratory methods Water in the saturated zone

Hydrogeological assessment of a basin Instrumentation

Geological subsurface techniques Geophysical subsurface techniques Accuracy

Additional requirements Distribution of measuring points

Infiltration Infiltrometers

Flood-type infiltrometers Ring infiltrometers

Cylinder or tube infiltrometers Rainfall-simulator infiltrometers Portable rainfall-simulator infiltrometers Operating sprinkler infiitrometers

Measurement of phytomorphological characteristics General

Measurement methods of surface vegetation Aerial photographs and field-sample plots Sampling herbaceous species and low shrubs Sampling trees and large shrubs

Special observations for evaporimeters and lysimeters Root depth and root density

Soil physical measurements Texture and structure Water relations

Moisture retention

Moisture-retention capacity and saturation-moisture capacity Water movement

Vapour versus liquid movement Measurement of soil frost and thaw

General

Measurement of soil frost and thaw Effect of exposure on freeze-thaw cycles Scope and purpose

Erosion studies Erosion and sedimentation

Erosional processes

Hillslope erosional processes Erosion studies on run-off plots Stream-channel erosional processes Measurement techniques

Measurement of erosion Hillslope erosion Stream-channel erosion

143 144 144 144 145 145 145 147 148 148 148 i 48 149 149 149 150 153 154 156 156 156 156 157 158 159 160 160 161 i 62 162 163 163 164 164 164 165 166 166 166 167 167 167 169 169 169 169 169 170

Contents

4.9.3.1 4.9.3.1.1 4.9.3.1 .I. 1 4.9.3.1.1.2 4.9.3.1.2 4.9.3.1.2.1 4.9.3.1.2.2 4.9.3.1.2.3 4.9.3.1.3 4.9.3.1.3. I 4.9.3.1.3.2 4.9.3.1.4 4.10 4.10.1 4.10.2 4.10.3 4.10.4 4.10.5 4.11 4.11.1 4.1 1.1.1 4.11.1.2 4.1 1.1.3 4.1 1.1.4 4.11.2 4.11.3 4.11.4 4.1 I .4.1 4.11.4.2 4.11.5 4.1 1.5.1 4.1 1.5.2 4.11.5.3 4.12 4.13

Techniques of sediment measurement

Measurement of suspended-sediment discharge Sampling equipment

Sampling procedure Measurement of bed load

Samplers Gauging methods Bed-material observations Filtration method

Methods for determining particle-size distribution Determination of concentration and particle size

Sedimentation surveys in small reservoirs Measurement of water quality

Purpose of water-quality measurements Frequency of measurements

Location of sampling Sampling methods

Chemical and physical analysis Sediment-transport measurements Use of radioactive tracers

Space-integration method Time-integration method Equipment required

Suspended-sediment measurements

Measurement of the water content of the snow pack Soil-moisture and density measurements

Ground-water tracing, velocity and direction measurements, determination of the effective porosity

Simple point-to-point tracing experiments for the determination of the hydraulic continuity and direction and velocity of ground water Determination of the effective porosity and dilution techniques for the determination of the direction and velocity of ground water

Deuterium and oxygen-I8 Tritium and carbon-14 General

Environmental isotope techniques

Minimum equipment

Location of instruments and equipment in a basin References

5 Data processing and publication

5.0 5. I 5.1.1 5.1.1.1 5.1.1.2 5.1.1.2. I 5.1.1.2.2 5.1.1.2.3 5.1.1.3 5.1.1.3.1 5.1.1.3.2 5.1.2 5.1.2.1 5.1.2.1.1

General

Mapping of representative and experimental basins Topographical mapping

Techniques Features

Contours Basin divide

Drainage net and cultural features Base maps

Size of maps Construction of maps

Geological and hydrogeological mapping Mapping of surface geology

Techniques

-

172 172 1 72 172 172 172 173 174 174 174 174 174 175 175 175 175 176 176 176 177 177 177 117 177 177 I 78 178 179 179 179 180 181 183 i 83 186 186

196 196 197 197 197 197 197 197 198 198 198 I 98 200 200

Contents

5.1.2.1.2 5.1.2.1.3 5.1.2.2 5.1.2.2.1 5.1.2.2.1.1 5.1.2.2.1.2 5.1.2.2.2 5.1.2.2.3 5.1.3 5.1.3.1 5.1.3.2 5.1.4 5.1.4.1 5.1.5 5.1.6 5.1.6.1 5.1.6.2 5.1.6.3 5.1.7 5.1.7.1 5.1.7.2 5.1.8 5.1.9 5.2 5.3 5.3.1 5.3.1.1 5.3.1.2 5.3.1.3 5.3.1.4 5.3.1.5 5.3.2 5.3.2.1 5.3.2.2 5.3.3 5.3.4 5.3.4.1 5.3.4.2 5.3.4.3 5.3.4.4 5.3.4.5 5.3.4.6 5.3.4.7 5.3.5 5.3.5.1 5.3.5.2 5.3.5.3 5.3.5.4 5.3.5.5 5.4 5.4.1 5.4.2 5.4.3 5.4.4 5.4.5 5.4.6 5.4.7

Features Cartography Techniques Subsurface mapping

Hydrogeological mapping Geological engineering mapping Features

Cartography Pedological mapping

Techniques

Features of a soil map Vegetation maps

Vegetation surveys Geomorphological mapping Land-inventory mapping

Techniques Features Cartography

Terrestrial photography Aerial photography

Aerial and terrestrial photography

Cartographical description of physiographical characteristics Inventory of observations and research made on representative perimental basins

Recommendations on routine data-processing methods Climatic data

Precipitation

Consistency of records Point rainfall record

Routine methods of determining mean basin rainfall Other methods of determining mean basin rainfall Other methods of processing precipitation data Errors in snow data

Tests for consistency Snow cover

Interception of precipitation by vegetation Evaporation

Water-balance method Pan evaporation Energy-balance method Aerodynamic method Empirical equations

Evaporation from soil and snow cover Actual evapotranspiration

Wind Temperature Humidity Radiation Energy balance Surface water

General Charts and tapes

Tabulation of time and stage heights

Stage-discharge relations and ponding corrections Mean discharge

Run-off calculations

Approximate checks on validity of streamflow Other climatic observations, including energy balance

200 200 202 202 202 203 203 203 204 204 204 207 207 209 209 209 209 209 210 210 21 I 21 1 212 212 213 213 283 214 214 216 216 216 217 218 218 218 218 219 219 220 220 22 L 222 222 223 223 223 223 223 225 225 225 225 226 227 227 229 and ex-

6.1 6.1.1 6.1.1.1 6.1.1.2 6.1.1.2.1 6.1.1.2.2 6.1.1.2.3 6.1.1.2.4 6.1.1.2.5 6.1.1.2.6 6.1.1.2.7 6.1.1.2.8 6.1.1.3 6.1.1.4 6.1.2 6.1.2.1 6.1.2.2

General

Basin characteristics Vegetation characteristics Geomorphological characteristics

Area elevation curve- median elevation Maximum and minimum elevations Aspect

Maximum valley side slope Mean slope curve Hypsometric curve Slope index

Drainage characteristics Pedological characteristics Hydrogeological characteristics

Definition of the climatic characteristics of a basin

Study of variations of climatic characteristics in relation to hydrological characteristics or processes

Analysis of climatic characteristics and energy balance

264 264 265 266 266 266 266 266 266 267 268 269 270 27 1 272 272 272 Contents

5.5 5.5.1 5.5.1.1 5.5.2 5.5.2.1 5.5.2.2 5.5.2.3 5.5.2.3.1 5.5.2.3.2 5.5.2.3.3 5.6 5.6.1 5.6.2 5.6.3 5.6.4 5.7 5.8 5.8.1 5.8.1.1 5.8.1.2 5.8.1.3 5.8.1.4 5.8.1.4.1 5.8.1.4.2 5.8.2 5.9 5.9.1 5.9.2 5.10 5.10.1 5.10.2 5.10.3 5.10.4 5.10.5

Subsurface water

Water in the unsaturated zone Soil moisture

Water in the saturated zone General considerations Errors of measurement Methods of presentation of data

Ground-water levels Fluctuation diagrams Ground-water contour maps Erosion and sedimentation

Sediment-rating curves Calculation of sediment yield Relation to deposits in reservoirs Interpretation of results

Water quality

Automated processing of data Automated processes

Digital recorder Pencil follower Punchcard system Computer programmes

Digital recorder programme Examples of programmes available Some considerations regarding data automation Data storage and retrieval

General considerations Microfilm aperture punchcards Publication of summaries

Purpose of publishing Publication requirements Frequency of publication Contents and format Publication of summaries References

229 229 229 230 230 230 23 1 23 1 23 1 232 233 233 233 235 235 235 236 236 236 236 236 238 238 239 240 240 240 241 24 1 24 1 243 260 260 260 260

6 Analysis techniques and interpretation of research results

6.1.2.2.1 6.1.2.2.2 6.1.2.2.3 6.1.2.2.4 6.1.2.2.5 6.1.2.2.6

1

6.1.3. I 6.1.3.2 6.1.3.2.1 6.1.3.2.2 6.1.3.2.3 6.1.3.3 6.1.3.3.1 6.1.3.3.2 6.1.3.4 6.1.3.5 6.1.3.5.1 6.1.3.5.2 6.1.3.5.3 6.1.3.5.4 6.1.3.5.5 6.1.3.5.6 6.1.3.5.7 6.1.3.5.8 6.1.4 6.1.4.1 6.1.4.2 6.1.4.3 6.1.4.3.1 6.1.4.3.2 6.1.4.3.3 6.1.4.3.4 6.1.4.4 6.1.4.4.1 6.1.4.4.2 6.1.4.4.3 6.1.5 6.1.5.1 6.1.5.2 6.1.5.3 6.1.5.4 6.1.5.5 6.1.6 6.2

I

6.2.1 6.2.2 6.2.3 6.2.4 6.2.5 6.2.5.1 6.2.5.2 6.2.5.3

~ 6.2.5.3.1 6.2.5.3.2 6.2.5.3.3

Precipitation Snowmelt Temperature Solar radiation Humidity Evaporation Energy balance

Standard hydrological characteristics Various forms of flow, recession studies Surface water

Master recession curves Recession equations Storage relations Hydrograph analysis

Flow separation

Miscellaneous characteristics defining the hydrograph Volume of flow (surface or direct run-off)

Infiltration analysis General methodology Sprinkling-plot analysis Run-off plot analysis Natural basin analysis

Natural basin analysis using a flow-limit curve

Natural basin analysis by the time-condensation method Infiltration equations

Storage-flow relationships Subsurface water

General

Principles of subsurface flow Unsaturated-flow analysis

Types of infiltration

Infiltration at a constant rate, capillary rise Ponded rainfall infiltration

Ponding infiltration Saturated-flow analysis

Flow analyses from ground-water contour maps

Contents

273 274 274 274 274 274 274 274 275 275 276 277 277 277 277 280 28 1 28 1 282 282 284 284 285 287 287 289 29 1 29 1 29 1 293 293 293 296 298 301 301 Flow analyses based on piezometric heads near free water surfaces Flow analyses in drained areas

Erosion and sedimentation Analysis of study data

Relation of basin area to sediment yield Relation of relief and length to sediment yield Relation of drainage density to sediment yield Other basin characteristics affecting sediment yield Water quality

Relation between elements of the hydrological cycle and between these and basin characteristics in approximately stationary condition

General

Time variability of basins

Uncertainty as regards system inputs and outputs Non-linearity of hydrological processes

Types of model Linear normal models Graphical analysis

Models with a central linear element (unit hydrograph) General

Concept of unit hydrograph Determination of unit hydrograph

303 307 309 309 309 310 310 311 312 312 312 313 313 313 313 315 315 317 317 317 318

Contents

6.2.5.4 6.2.5.5 6.2.5.5.1 6.3 6.3.1 6.3.1. I 6.3.1.2 6.3.1.3 6.3.2 6.3.2.1 6.3.3 6.4 6.5 6.5.1 6.5.2 6.5.3 6.5.4

Non-linear functional models (general non-linear analysis) Conceptual models (general synthesis)

Automatic parameter adjustment Natural and cultural changes

Graphical analysis and linear normal models Test of representativeness of period of study Single-basin technique

Comparative-basin technique Hydrological characteristics

Example of working hypothesis Other mathematical models Water-balance studies

Translation of results to other basins Flood prediction

Long-range prediction of streamflows Short-term prediction of streamflows S u m m a r y of prediction techniques References

Bibliography

320 321 323 324 324 325 325 321 331 332 332 335 336 336 338 338 338 34 I

341

Foreword

Since the inception of the IHD programme, it has been apparent that the development of hydrological research should include the perfecting of research methodology on specially chosen and equipped basins. Such basins, designated ‘representative’ or

‘experimental’ basins, are of great value for hydrological research and for the training of research workers when the standards of organization and functioning comply with clearly defined research aims.

A Symposium on Representative and Experimental Basins was organized by Unesco in collaboration with the Hungarian Government with the participation of the Inter- national Association of Scientific Hydrology (IASH) in Budapest in September 1965 in order to study a wide range of experiments and the results obtained, so that general guidelines could be formulated for these basins. These guidelines are intended mainly for countries wishing to establish such research basins, but are useful also for improving the effectiveness of research already in progress.

The Co-ordinating Council of the I H D formed an ad hoc Working Group to draw up, from the conclusions of the symposium, the principles for organizing representative and experimental basins. This Working Group was asked to analyse the results of an investigation undertaken on the current state of hydrological research being conducted or contemplated in such basins in various countries. The growth of projects related to the creation of representative and experimental basins in the countries participating in the Decade, and the importance of independent experiments performed in several countries, led the Working Group to propose to the Co-ordinating Council the preparation of a guide for international research and practice in representative and experimental basins, based on existing documentation.

This technical guidance material outlines the methodological principles for the organization and functioning of representative and experimental basins according to the specific aim of the research undertaken. In order that it could be used for the setting up of IHD national programmes, it was necessary to prepare the guide as soon as possible.

With this aim in view, the Co-ordinating Council, at its second session in April 1966, established a permanent Working Group, which had as its main task the preparation of this guide, and asked it to nominate from its members a Panel of Experts to complete this task.

The Panel thus formed met for the first time in October 1966. T w o draft guides were prepared, including contributions and material received from national committees for the IHD. One was edited by Mr. Toebes, with Messrs. Hadley and Jacquet as sub-editors, and the other was edited by Dr. Ouryvaev, and prepared in the U.S.S.R. The two guides were combined at successive meetings of the chief editors, of the Panel and of the

Foreword

Working Group. The publication of the project was endorsed by the Co-ordinating Council at its third session in M a y 1967.

The guide comprises six chapters:

The Introduction describes the aims of the publication and the purpose of representative and experimental basins within the larger framework of hydrological research;

Chapter 2 gives the criteria for selecting sites and for organizing a network of basins;

Chapter 3 deals with the organization and planning of observations according to the Chapter 4 contains descriptions of methods of observation and types of instruments Chapter 5 gives a wide range of methods for data processing, synthesis, and preparation Chapter 6 deals with analysis techniques and interpretation of the results obtained.

The present publication, thus prepared in a very short period of time, obviously presents imperfections and gaps. Nevertheless, it is hoped that it will serve as a valuable source of guidance material, especially for countries in which this type of investigation is just beginning, and will at the same time offer a framework for the international exchange of experience in this field of hydrological research.

The Working Group which prepared this first version of the guide has also been entrusted with the responsibility of collecting additional data and formulating various improvements to the present text; particularly with reference to Chapters 3 and 6, both of which are important prerequisites of successful research on representative and experimental basins.

All IHD national committees are invited to send comments on the contents and to forward complementary scientific material with a view to perfecting the guide. Such contributions would be especially welcomed from countries where interesting new results have been obtained from investigations. This information will be collected by the Secretariat and passed on to the Working Group.

aims of the research being carried out on the basins;

to be used for the study of the various parameters of the hydrological cycle;

for publication;

18

List ^of contributors

ALLEN Jr., W. H., United States Department of Agriculture, Agricultural Research Service, AMOROCHO, J., University of California, Davis, U.S.A.

BERNIER, J., Electricité de France, CREC, France.

BLAKE, G. J., Ministry of Works, Water and Soil Division, N e w Zealand.

BLOEMEN, G., Institute for Land and Water Management, The Netherlands.

BLOK, T., Provinciale Waterstaat, Gelderland, The Netherlands.

BOCHKOV, A. P., State Hydrological Institute, U.S.S.R.

BRANSON, F. A., United States Department of Interior, United States Geological Survey, U.S.A.

COLENBRANDER, H. J., Rijkswaterstaat, The Netherlands.

DAGG, M., East African Agriculture and Forest Research Organization, Kenya.

DAVIS, G. H., International Atomic Energy Agency.

DINÇER, T., International Atomic Energy Agency.

DOOGE, J., University College, Cork, Ireland.

ENGLAND, C. B., United States Department of Agriculture, Agricultural Research Service, FOURNIER, F., Office de la Recherche Scientifique et Technique Outre Mer, France.

HADLEY, R. F., United States Department of Interior, United States Geological Survey, U.S.A.

HARROLD, L. L., United States Department of Agriculture, Agricultural Research Service, HELVEY, J. D., United States Department of Agriculture, United States Forest Service, U.S.A.

HERAS, R., Instituto de Hidrología, Madrid, Spain.

HOLTAN, H . M., United States Department of Agriculture, Agricultural Research Service, U.S.A.

JACKSON, R. J., Department of Scientific and Industrial Research, N e w Zealand Soil Bureau, N e w Zealand.

JACQUET, J., Electricité de France, CREC, France.

JOHNSON, A. I., United States Department of Interior, United States Geological Survey, U.S.A.

KELLY, L. L., United States Department of Agriculture, Agricultural Research Service, U.S.A.

KOVZEL, A. G., State Hydrological Institute, U.S.S.R.

KRAYENHOFF V A N DE LEUR, D. A., University of Wageningen, The Netherlands.

KRESTOVSKY, O. I., State Hydrological Institute, U.S.S.R.

KUPRIANOV, V. V., State Hydrological Institute, U.S.S.R.

KUZIN, P. S., State Hydrological Institute, U.S.S.R.

KUZMIN, P. P., State Hydrological Institute, U.S.S.R.

MCQUEEN, I. S., United States Department of Interior, United States Geological Survey, U.S.A.

MILLER, R. F., United States Department of Interior, United States Geological Survey, U.S.A.

MORRISSEY, W . B., Ministry of Works, Water and Soil Division, N e w Zealand.

NASH, J. E., University College, Galway, Ireland.

O'DONNELL, T., Imperial College of Science and Technology, London, United Kingdom.

U.S.A.

U.S.A.

U.S.A.

List of contributors

OURYVAEV, V. A., State Hydrological Institute, U.S.S.R.

PACKER, P., United States Department of Agriculture, United States Forest Service, U.S.A.

POPOV, O. V., State Hydrological Institute, U.S.S.R.

PUSHKAROV, V. F., State Hydrological Institute, U.S.S.R.

ROCHE, M., Office de la Recherche Scientifique et Technique Outre Mer, France.

RODDA, J., Natural Environment Research Council, Hydrological Research Unit, United

RODIER, J., Office de la Recherche Scientifique et Technique Outre Mer, France.

SHOWN, L. M., United States Department of Interior, United States Geological Survey, U.S.A.

SPENGLER, O. A., State Hydrological Institute, U.S.S.R.

SUBBOTIN, A. I., U.S.S.R. Hydrometeorological Centre, U.S.S.R.

TAKENOUCHI, T., Water Resources Development Public Corporation, Japan.

TISON, L. J., International Association of Scientific Hydrology.

TOEBES, C., Ministry of Works, Water and Soil Division, N e w Zealand.

UBELL, K., Institute for Water Resources, Hungary.

VISSER, W. C., Institute for Land and Water Management, The Netherlands.

VOLFTSUN, I. B., State Hydrological Institute, U.S.S.R.

WESSELING, J., Institute for Land and Water Management, The Netherlands.

Kingdom.

In addition, material was provided by the Secretariat of the Canadian National Committee in the form of proceedings of the National Workshop Seminar on Research Basin Studies held in Ottawa, 1966.

20

Introduction

1.1

Scope and purpose

This guide deals with the establishment and operation of representative and experimental basins and aims at suggesting desirable methods and possible avenues of research.

Hydrological research on representative and experimental basins has suffered not only from a lack of basic data and a lack of standardization of observation and processing techniques, but also from research methods giving only a limited understanding of the physical processes occurring in basins. Research in representative and experimental basins has frequently been treated as a statistical experiment but, apart from the fact that classical statistical methods are not always applicable to hydrological data, the results are of limited value since no methodology has been evolved to translate the research findings to other basins. Moreover, the aim of hydrological research is not only the collection of data, but rather an interpretation of these data for use in the solution of management problems.

All basin studies, regardless of the classification evolved, should be planned so as to further understanding of the mathematical and physical relationships between the various components of the hydrological cycle. Principal objectives of hydrological research on representative and experimental basins are the prediction and quantitative estimation of these components. For these purposes it is necessary to organize special experiments and to carry out complex hydrological research on individual aspects of the hydrological regimen in experimental basins (which are under the influence of man) as well as studies in representative basins (which are in their natural state). It is evident that the scope of experimental investigations should be based on the practical needs, taking into account physiographical conditions, of a given country.

It is very difficult to conduct such investigations. In every case an individual approach is required, and these investigations should therefore be considered only when objectives are clear and funds and trained personnel are available.

The primary aim of this guide is, therefore, to foster more detailed research into physical processes occurring in natural basins and at the same time to attack the elements of uncertainty in hydrology. Since this type of research is both time-consuming and expensive, the basin studies should be planned in detail and should allow for accurate standardized data observation and data processing. Immediate analysis of the data is necessary to establish needs for additional observations or for indicating those observations which may be discontinued. Concurrent research in mathematical and statistical techniques may be utilized to test hypotheses and to develop models for part of or for the whole of the hydrological cycle.