Proceedings of the Madrid Symposium ,June 1973

of

resources projects

with inadequate data

Proceedings of the Madrid Symposium ,June 1973

Elaboration des projets

d'utilisation des ressources en eau

c dans données suffisantes

Volume I

Actes du colloque de Madrid Juin I973

Unesco - ^MIMO - ^1AHS

Unesco - O M M - ^AISH

_-

Studies and reports in hydrology/Études et rapports d’hydrologie

16

1. T h e use of analog and digital computers in hydrology: Proceedings of the Tucson Symposium.

June 1966 1 L'utilisation des calculatrices analogiques et des ordinateurs en hydrologie: Actes d u colloque de Tucson, juin 1966. Vol. I & 2. Co-edition IAHS-Unesco / Coédition AISH-Unesco.

Water in the unsaturated zone: Proceedings of the Wageningen Symposium, June 1967 1 L'eau dans la zone non saturée: Actes d u symposium de Wageningen, juin 1967. Edited by 1 edité par P. E.

Rijtema & H . Wassink. Vol. 1 & 2. Co-edition IAHS-Unesco 1 Coédition AISH-Unesco.

3. Floods and their computation: Proceedings of the Leningrad Symposium, August 1967 / Les crues et leur évaluation: Actes du colloque de Leningrad, août 1967. Vol. 1 & 2. Co-edition IAHS-Unesco- W M O 1 Coédition AISH-Unesco-OMM.

4. Representative and experimental basins: A n international guide for research and practice. Edited by C. Toebes and V. Ouryvaev. Ptrblished by Unesco.

4. Les bassins représentatifs et expérimentaux: Guide international des pratiques en matikre de re- cherche. Publié sous la direction de C. Toebes et V. Ouryvaey. Publié par l'Unesco.

5. 'Discharge of selected rivers of the world 1 Débit de certain cours d'eau d u monde. Published by Unesco 1 Publié par l'Unesco.

Vol. I : General and régime characteristics of stations selected / Caractéristiques générales et caractéristiques d u régime des stations choisies.

Vol. II: Monthly and annual discharges recorded at various selected stations (from start of obser.

vations up to 1964) / Débits mensuels et annuels enregistrés en diverses stations sélectionnées (de l'origine des observations à l'année 1964).

'Vol. III: M e a n monthly and extreme discharges (1965-1969) I Débits mensuels moyens et débits extrêmes (1965-1969).

6. List of International Hydrological Decade Stations of the world 1 Liste des stations de la Décennie h'ydrologique internationale existant dans le m o n d e . Published by Unesco 1 Publié par l'Unesco.

7. Ground-water studies: A n international guide for practice. Edited by R . Brown, J. Ineson, V. Ko- noplyantsev and V. Kovalevski. (Will also appear in French, Russian and Spanish 1 Paraitra également en espagnol, en français et en russe.)

8. Land subsidence: Proceedings of the To'kyo Symposium, September 1969 1 Affaisement d u sol:

Actes d u colloque de Tokyo, septembre 1969. 'Vol. 1 & 2. Co-edition IAHS-Unesco / Coédition AISH-Unesco.

9. Hydrology of deltas: Proceedings of the Bucharest Symposium, M a y 1969 1 Hydrologie des deltas:

Actes d u colloque de Bucarest, m a i 1969. Vol. 1 & 2. Co-edifion IAHS-Unesco I Coédition AISH- Unesco.

10. Status and trends of research in hydrology 1 Bilan et tendances de la recherche en hydrologie.

Published b y Unesco 1 Publié par l'Unesco.

11. World water balance: Proceedings of the Reading Symposium, July 1970 1 Bilan hydrique mondial:

Actes d u colloque de Reading, juillet 1970. Vol. 1-3. Co-edition I A H S - U n e s c o - W M O / Coédition AISH-Unesco-OMM.

12. Results OF research on representative and experimental basins: Proceedings of the Wellington Symposium, December 1970 1 Résultats de recherches sur les bassins représentatifs et expérimen- taux: Actes d u cowoque de Wellington, décembre 1970. 'Vol. 1 & 2. Coedition IAHS-Unesco 1 Coédition AISH-Unesco.

13. Hydrometry: Proceedings of the Koblenz Symposium, September 1970 1 Hydrométrie: Actes d u colloque de Coblence, septembre 1970. Co-edition I A H S - U n e s c o - W M O 1 Coédition AISH-Unesco- O M M .

14. Hydrologic information systems. Co-edition Unesco-WMO.

15. Mathematical models in hydrology: Proceedings of the W a r s a w Symposium, July 1971 1 Les mo- dèles mathématiques en hydrologie: Actes d u colloque de Varsovie, juillet 1971. Vol. 1-3. Co- edition I A H S - U n e s c o - W M O / Coédition AISH-Unesco-OMM.

16. Design of water resources projects with inadequate data: Proceedings of the Madrid symposium, June 1973 1 filaboration des projets d'utilisation des ressources en eau sans données suffisantes:

Actes d u colloque de Madrid, juin 1973. Vol. 1-3. Co-edition U n e s c o - W M O - I A H S / Coédition Unesco- O M M - A I S H .

2.

qesign of

water resources projects with inadequate data :

Proceeúings of the

Madrid

Symposium .lune 1973

Elaboration des projets

d’utilisation des ressources en eau

sans données suffisantes

Actes du colloque de Moúrid .luin 1973

A contribution to the Iniernaiional Hydrological Decade U n e contribution a la Décennie hydrologique internationale C o n resurnenes en espano1

Volume

I

Unesco - W M O - LAHS 1974

Unesco - ^{O M M} - AISH

7, Place de Fontenoy, 75700 Paris, World Meteorological Organization, 41 av. Giuseppe-Motta, Geneva, and

the International Association of Hydrological Sciences (President:

J.-A.

Rodier), 19, rue Eugène-Carrière, 75018 Paris

Publié conjointement par

l’Organisation des Nations Unies pour l’éducation, la science et la culture, 7, place de Fontenoy, 75700 Paris, l’organisation météorologique mondiale, 41, av. Giuseppe-Motta, Genève, et

l’Association internationale des sciences hydrologiques (président: J.-A. Rodier).

19, rue Eugène-Carrière, 75018 Paris

Impreso por el Centro de Estudios Hidrográficos, Madrid

The selection and presentation of material and the opinions expressed in this publication are the responsibility of the authors concerned and do not necessarily reflect the views of the publishers.

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

Le choix et la présentation du contenu de cet ouvrage et les opinions qui s’y expriment n’engagent que ia responsabilité des auteurs et ne correspondent pas nécessairement aux vues des éditeurs.

Les dénominations employées et la présentation des divers éléments n’impliquent de la part des éditeurs aucune prise de position à l’égard du statut juridique de l’un quelconque des pays et territoires en cause, de son régime politique ou du tracé de ses frontières.

ISBN 92-3401137-1 0 UnescuWMO-IAHS-1974 Printed in Spain

P k E F A C E

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 spe- cialists 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 1974 National Committees for the Decade had been formed in 108 of Unesco’s 131 Member States to carry out national activities within the programme of the Decade. The implementation of the programme is supervised by a Co-ordinating Council, composed of 30 Member States selected by the Ge- neral 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 techni- ques, 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 streng- then 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 re- search 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 contacts between research workers

in

this field. To this end Unesco initiated two series of publications: Studies and Reports in Hydrology and Technical Papers in Hydrology.

The Studies and Reports in Hydrology series, in which the present volume is published, is aimed at recording data collected and the main results of hydrwlogical studies undertaken within the framework of the Decade, as

well

as providing information on research techniques. Also included in the series are proceedings of symposia. Thus, the series com- prises the compilation of data, discussions of hydrological research techni- ques and findings, and guidance material for future scientific investigations.

It is hoped that the volumes w i l l furnish material of both practical and theoretical interest to hydrologists and governments participating in the I H D and respond

to

the needs of technicians and scientists concerned with problems of water in all countries.

A number of these volumes have been published jointly with the In-

ternational Association of Hydrological Sciences and the World Meteoro-

logical Organization which have co-operated with Unesco in the imple-

mentation of several important projects of the IHD.

La Conférence générale de l’Unesco, à sa treizième session, a décidé de lancer, pour la période s’étendant de 1965

à

1974, la Décennie hydrologique internationale (DHI), entreprise mondiale visant a faire progresser la con- naissance en matiere

ci’

vdrologie scientifique par un développement de la coopération inyrnati nale et par la formation de spécialistes

et

de techniciens.

A u

moment

oìi

l’expansion démographique et le développement industriel et agricole provoquent un accroissement constant des besoins en eau, la DHI permet

à

tous les pays de mieux évaluer leurs ressources hydrauliques

et

de les exploiter plus rationnellement.

I1 existe actuellement dans 108 des 131 Etats membres de l’Unesco un comité national qui, pour tout ce qui a tratit au programme de la Décen- nie, impulse

les

activités nationales et assure la participation de son pays aux entreprises régionales et internationales. L’exécution du programme de la DHI se fait sous la direction d’un Conseil de coordination composé de 30 Etats membres désignés par la Conférence générale de l’Unesco; ce conseil étudie

les

propositions concernant le programme, recommande l’adoption de projets intéressant l’ensemble des pays ou un grand nombre d’entre eux, aide

à

la mise sur pied de projets nationaux et régionaux, et coordonne la coopération à l’échelon international.

Le programme de la DHI, qui porte sur tous les aspects des études et des recherches hydrologiques, vise essentiellement

à

développer la col- laboration dans la mise au point des techniques de recherches, dans la diffusion des données hydrologiques, dans l’organisation des installations hydrologiques. I1 encourage les enquêtes nationales, régionales et interna- tionales tendant à accroître et

à

améliorer l‘utilisation des resources na- turelles, dans une perspective locale et générale. Il permet aux pays avancés en matière de recherches hydrologiques d’échanger des informations; aux pays en voie de développement, il offre la possibilité de profiter de ces échanges pour élaborer leurs projets de recherches et pour planifier leurs installations hydrologiques en tirant parti des acquisitions les plus récentes de l’hydrologie scientifique.

Pour permettre a l’Unesco de contribuer au succès de la DHI, la Con- férence générale a autorisé le Directeur générale

à

rassembler, à échanger et à diffuser des informations sur les recherches d’hydrologie scientifique et à faciliter les contacts entre les chercheurs dans ce domaine. A cette fin, l’Unesco fait paraître deux nouvelles collections de publications: «Etu- des et rapports d’hydrologie» et «Notes techniques d’hydrologie,.

La collection «Etudes et rapports d’hydrologie,, dans laquelle est publié le présent ouvrage, a pour objet de présenter les données recueillies et les principaux résultats des études effectuées dans le cadre de la Décennie et de fournir des informations sur

les

techniques de recherche. On y trouve aussi les Actes de colloques réunis sur ce sujet. Cette collection publie donc des données, des techniques et des résultats de recherches ainsi qu’une documentation pour les travaux scientifiques futurs.

O n espère que ces volumes apporteront aux hydrologues et aux gou- vernements qui participent à ,la DHI des matériaux d’un intérêt tant pra-

e

tique que théorique, et qu’elle répondra aux besoins des techniciens et des h o m m e s de science de tous pays qui s’occupent des problèmes de l’eau.

Certains de ces ouvrages sont publibs en coopération avec l’Association internationale des sciences hydrologiques ou l’organisation météorologique mondiale dans le cadre de projets réalisés conjointement par ces orga- nisations et l’Unesco.

The Symposium on the Development of Water Resources Projects

with

Inadequate Data was held in Madrid from

4

to

8

June 1973 for the purpose of focusing on the methodology for hydrologic studies for water resources projects with inadequate data and on current practices for the assessment of design parameters.

T h e Symposium w a s opened at the Palacio de Exposiciones o n the morning of

4

June by Miniester of Public Workes of Spain Addresses were then given by Dr. Dumitrescu o n behalf of the Director General of Unesco, Professor N e v m e c on behalf of the Secretary-General of

WMO,

Dr. Rodier as President of I A H S and by Dr. Briones, on behalf of the Spanish N a - tional Committee for the I H D .

T h e Symposium w a s attended by

480

participants from 77 countries.

The technical programme, detaimled in the Table of Contents, included consideration of 3 major areas:

1. Methodology for hydrological studies with inadequate data,

2.

Current practices in different countries,

3.

Relation between project economics and hydrological data.

Each area was further sub-divided into topics for each of which the individually contributed papers were abstracted into a general report, orally presented by an invited expert, and followed by discussion.

Since the individual papers were not presented at the Symposium orally by the authors, thery are reproduced here in the orden in which they were reported

in

each general report under each topic.

üesip d water reswrcee projects with inadequate dati: Pmeeedin.p d the Madrid 8ympoilUm.

June i973 / Blabontion de# projeu d‘utilhition des ressourcci en eau rans domdes nuttlrantei:

Acui du mlloque de Madrid, juin 1973.

Volume I Contents Table des matieres

Foreword/Avant-propos

TOPIC 1.1 . TRANSFER OF INFORMATION FROM OBSERVED POINTS TO POINTS OF INTEREST, ESPECIALLY FOR THE ASSESSMENT OF THE CHARACTERISTICS OF DISCHARGES.

POINT 1.1

-

EXTRAPOLATION DES INFORMATIONS RECUEILLIES AUX RET PARTICULIER, NOTAMMENT POUR L’EVALUATION DES DEBITS CARACTERISTIQUES.

POINTS OBSERVES A DES POINTS PRESENTANT UN INTE-

SOKOLOV, A.A. (U.S.S.R.) GENERAL REPORT

ALBINET, M., CASTANY, G., DELAROZIERE-BOUILLIN, O., JONAT, R., MARGAT, J. (FRANCE)

Evaluation et répartition des ressources en e a u d’une grande région par les paramétres hydroclimatiques et hydrog6ologiques ...

BALEK, J. (CZECHOSLOVAKIA)

Use of representative and experimental catchments for the assement of hydrological data of African tropical basins ...

CORMARY, Y

-

^{J.M. MASSON. (FRANCE)}

Diverses méthodes convergentes pour l’utihtion de l’information a I’écheUedgionale . . .

DUBREUIL, PIERRE. (FRANCE)

Le transfert d’infomtion hydrologique a des bassins versants non obser- vés . . .

GARCIA-AGREDA, R., RASULO, G., VIPARELLI, R. (ITALY)

Pluviometric zones and the criteria to define their boundaries for regions withscarcedata ...

OBERLIN, G.R., GALEA, G.C., TONI, J.T. (FRANCE)

Estimation des étiages de bassins non equipés . . .

1

15

27

47

61

89

103 TIERCELIN, J.R. (FRANCE)

ParamBtres régionaux relatifs aux ressources en eau. Utilisation. PdciPion

d’estimation ... 125 VAN HYLCKAMA, T.E.A. (U.S.A.)

Estimating evapotranspiration by homoclimates ... 74

reaowcea in the abuncl of oburvrtiona on the bu& of goographid interpoiation of runoff puameten ...

VUGLLNSKI, V.S., SEMENOV, V.A. (U.S.S.R.)

Evaiurtion of water IWOIUWW of mounîdn am11 in cani of r h n c e or inadequacy of datr on runoff ...

TOPIC 1.2

-

THE IMPROVEMENT OF OVERALL HYDR0UX;IC INFOR- MATION BY SHORT-TERM ADDITIONAL AND PARTICULAR OBSERVATIONS AND MEASUREMENTS. INCLUDING THE PAIGN USING HYDROLOGIC DATA SENSITIVITY ANALYSIS BASED ON PROJECT ECONOMICS.

PLANNING OF THE ADDITIONAL MEASUREMENT CAM-

POINT 1.2

-

AMELIORATION DE L'ENSEMBLE DE L'INFORMATION HYDROLOGIQUE AU MOYEN DE COURTES CAMPAGNES DE MESURES COMPLEMENTAIRES ET D'OBSERVATIONS PARTI- CULIERES, COMPRENANT LA MISE EN OEUVRE DE CAM- PAGNES DE MESURES ADDITIONNELLES UTILISANT UNE ANALYSE DE SENSIBILITE DES DONNEES BASEE SUR L'ECONOMIE DES PROJETS.

RODDA, JOHN (U.K.) GENERAL REPORT BEARD, LEO R. (U.S.A.)

Hydrological data fiii-in and network design . . .

DELHOMME, J.P., DELFINER, P. (FRANCE)

Application du Krigeage a l'optimisation d'une campagne pluviométrique enzonearide ...

HALASI-KUN, GEORGE, J. (U.S.A.)

Improvement of runoff records in smaller watersheds based on permeabi- lity of the geological subsurface ...

KOVACS, GEORGE. MOLNAR, GEORGE. (HUNGARY)

Determination of snow water equivalent and snowmelt water by thickness of snow cover data . . .

MEIJERINK, A.M.J. (NETHERLANDS)

Evaluation of local water resources in semiarid hard rock region by using photo.hydrological indices . . .

PANT,P.S.,GUPTA, M.G. (INDIA)

Application of satellite cloud pictures in snow hydrology of the Himala-

yas and in the estimation of rainfall over India during southwest monsoonseason . . .

137

145

153

161

17

191

205

217

233

I

TOPIC I.3A

-

THE USE OF SIMULATION TECHNIQUES ESPECIALLY DE- SIGNED FOR DATA-SCARCE AREAS. STATISTICAL

ME-

THODS AND DATA OPERATION.

POINT I.3A

-

UTILISATION DES TECHNIQUES DE SIMULATION SPE- CIALEMENT EWIBOREE POUR DES REGIONS OU LES DONNEES SONT RARES. METHODES STATISTIQUES ET TRAITEMENT DES DONNEES.

JAMES, IVAN CHARLES. (U.S.A.) GENERAL REPORT CORMARY, Y . GUILBOT, A. (FRANCE)

Etude des relations pluie-débit sur trois bassins versants d’investigation . . CHARANIA, S.H. (KENYA)

Extension of runoff records for small catchments in semi-arid regions . . .

DAVYDOVA,A.I., KALININ, G.P. (U.S.S.R.)

Simulation of hydrological samples by natural water flow characteristics

HAMLIN, M.J., KOTTEGODA, N.T. (U.K.)

The preparation of a data set for hydrologic system analysis . . .

LENTON, ROBERTO L., SCHAAKE JR., JOHN C., RODRIGUEZ-ITURBE, IG- NACIO. (U.S.A.)

Potential application of Bayesian techniques for parameter estimation withlimiteddata . . .

McMAHON, T.A., MEIN, R.G. (AUSTRALIA)

Storage-yield estimates with inadequate streamflow data ...

MARTIN JADRAQUE, VALENTIN. (SPAIN)

Estimation of G u m b e l law parameters in small samples ...

MOSS, M.E.. DAWDY, D.R. (U.S.A.)

Stochastic simulation for basins with short or n o records of streamflow

O’CONNELL, P.E., WALLIS, J.R. (U.S.A.)

Choice of generating mechanism in synthetic hydrology with inadequate data ...

PORRAS, PEDRO., FLORES, ALFREDO. (VENEZUELA)

Stochastic application in ungauged basins for planning purposes ...

ROCHE, MARCEL. (FRANCE)

Homogdnbisation et interpolation des donndes pour un modèle de simula- tion ...

SHARMA, H.D., BHATTACHARYA, A.P., JINDAL, S.R. (INDIA)

T h e use of simulation techniques for sequential generation of short-sized rainfall data and its application in the estimation of design flood ...

241

265

281

293 305

321

335

349

365

311 355

407

419

Libbanon

...

WALLIS, J.R., MATALAS,

N.C.

(U.S.A.)

Rehtivr importuice of decidon vuirbiem in fiood frequency uulydi ...

WEISS,

G.

(U.K.)

Shot nohe models for aynthetic generation of multimite M ymunflow data ...

WOOD, ERIC F. (U.S.A.)

Flood control ddgn with Limited data . A comparinon of the chsical andBayesianapproaches ...

TOPIC 1.3B . THE USE OF SIMULATION TECHNIQUES ESPECIALLY DE- SIGNED FOR DATA-SCARCE AREAS. THE USE OF MATHE- MATICAL MODELS.

POINT I.3B

-

UTILISATION DES TECHNIQUES DE SIMULATION SPE- DONNEES SONT RARES. UTILISATION DES MODELES MA- CIALEMENT ELABOFSE POUR DES REGIONS OU LES THEMATIQUES.

NASH, J.E. (IRELAND) GENERAL REPORT BERNIER, J. (FRANCE)

Données inadéquates et modeles mathématiques de la pollution en riviere COOK, SAMUEL P., MBURU, SAMUEL G. (KENYA)

Regional groundwater recharge estimates via meteorological data ...

DELLEUR, J.W., LEE, M.T. (U.S.A.)

A rainfall-runoff model based on the watershed stream network ...

HANN, C.T. (U.S.A.)

Monthly streamflow estimation from limited data ...

KOREN, V.I., KUTCHMENT, L.S. (U.S.S.R.)

Obtaining deficient information by solving inverse problems for mathe- maticalrunoffmodels ...

ROFAIL, NABIL. (EGYPT)

The mathematical model of water balance for data-scarce areas ...

VILARO, FRANCISCO., CUSTODIO, EMILIO. (SPAIN)

Data acquisition and methodology for a simulation model of the Llobre-

gat Delta (Barcelona, Spain) ...

435

449

457

469

485

513

525

53 1

545

5 5 1

569

581

Contents

Table

des matieres

Volume I

ForewordIAvant-propos

...

TOPIC 1.1 - TRANSFER OF INFORMATION FROM OBSERVED POINTS TO POINTS OF INTEREST, ESPECIALLY FOR THE ASSESSMENT OF THE CHARACTERISTICS OF DISCHARGES.

POINT I. 1 - EXTRAPOLATION DES INFORMATIONS RECUEILLIES AUX POINTS OBSERVES A DES POINTS PRESENTANT UN INTE- RET PARTICULIER, NOTAMMENT POUR L’EVALUATION DES DEBITS CARACTERISTIQUES.

SOKOLOV, A.A. (U.S.S.R.) GENERAL REPORT

ALBINET, M., CASTANY, G., DELAROZIERE-BOUILLIN, O., JONAT, R., MARGAT, J. (FRANCE)

Evaluation

et répartition des ressources en eaux

d’une

grande région par les paramètres hydroclimatiques et hydrogéologiques ...

BALEK, J. (CZECHOSLOVAKIA)

Use of

representative

and experimental

catchments

for the

assessment

of

hydrological

data of African

tropical basins ...

CORMARY, Y - J.M. MASSON. (FRANCE)

Diverses

méthodes convergentes pour l’utilisation

de l’information

à

l’échelle

régionale ...

DUBREUIL, PIERRE. (FRANCE)

Le

transfert d’information hydrologique à

des

bassins versants non

obcer-

vés ...

GARCIA-AGREDA, R., RASULO, G., VIPARELLI, R. (ITALY)

Pluviometric

zones

and the

criteria to

define their

boundaries for regions

with

scarce data ...

OBERLIN, G.R., GALEA, G.C., TONI, J.T. (FRANCE)

Estimation

des étiages

de

bassins

non

equipés ...

TIERCELIN, J. R. (FRANCE)

Parametres régionaux relatifs aux ressources en eau.

Utilisation. Précision d’estimation

...

VAN HYLCKAMA, T.E.A. (U.S.A.)

Estimating

evapotranspiration

by

homoclimates

...

VOSKRESENSKI, K.P. (U.S.S.R.)

Principles

for the computation of the main characteristics of river

water

resources in the absence of observations on the basis of geographical interpolation of runoff parameters ...

VUGLINSKI, V.S.,SEMENOV, V.A. (U.S.S.R.)

Evaluation

of

water

resources of mountain areas in casi of absence or inadequacyofdataonrunoff ...

TOPIC 1.2 - THE IMPROVEMENT OF OVERALL HYDROLOGIC INFOR- MATION BY SHORT-TERM ADDITIONAL A N D PARTICULAR OBSERVATIONS A N D MEASUREMENTS. INCLUDING THE PAIGN USING HYDROLOGIC DATA SENSITIVITY ANALYSIS BASED ON PROJECT ECONOMICS.

PLANNING OF THE ADDITIONAL MEASUREMENT CAM-

POINT 1.2 - AMELIORATION DE L’ENSEMBLE DE L’INFORMATION HYDROLOGIQUE A U MOYEN DE COURTES CAMPAGNES DE MESURES COMPLEMENTAIRES ET D’OBSERVATIONS PARTI- CULIERES, COMPRENANT LA MISE EN OEUVRE DE CAM- PAGNES DE MESURES ADDITIONNELLES UTILISANT UNE ANALYSE DE SENSIBILITE DES DONNEES BASEE SUR L’ECONOMIE DES PROJETS.

RODDA, JOHN (U.K.) GENERAL REPORT BEARD, LEO R. (U.S.A.)

Hydrological data fiil-in and

network

design ...

DELHOMME, J.P., DELFINER, P. (FRANCE)

Application

du

Krigeage

à

l’optimisation

d’une campagne pluviométrique enzonearide ...

HALASI-KUN, GEORGE, J. (U.S.A.)

Improvement

of runoff records in

smaller watersheds

based on

permeabi-

lity of the geological subsurface ...

III

KOVACS, GEORGE. MOLNAR, GEORGE. (HUNGARY)

Determination of snow water

equivalent and

snowmelt water

by thickness of snow cover data ...

MEIJERINK, A.M.J. (NETHERLANDS)

Evaluation

of

local water

resources in semiarid

hard rock region

by using photo-hydrological indices ...

PANT, P.S., GUPTA, M.G. (INDIA)

Application

of satellite

cloud

pictures in

snow

hydrology

of the Himala-

yas and in

the

estimation

of

rainfall

over

India during southwest monsoonseason ...

TOPIC I.3A - THE USE OF SIMULATION TECHNIQUES ESPECIALLY DE- SIGNED FOR DATA-SCARCE AREAS. STATISTICAL ME- THODS AND DATA OPERATION.

POINT I.3A - UTILISATION DES TECHNIQUES DE SIMULATION SPE- CIALEMENT ELABOREE POUR DES REGIONS OU LES DONNEES SONT RARES. METHODES STATISTIQUES ET TRAITEMENT DES DONNEES.

JAMES, IVAN CHARLES. (U.S.A.) GENERAL REPORT CORMARY, Y - GUILBOT, A. (FRANCE)

Etude des

relations pluie-débit sur trois bassins versants d'investigation . .

CHARANIA, S.H. (KENYA)

Extension of runoff

records

for small

catchments in semi-arid regions ...

DAVYDOVA,A.I.,KALININ,G.P. (U.S.S.R.)

Simulation of hydrological

samples by

natural water flow

characteristics

HAMLIN, M.J., KOTTEGODA, N.T. (U.K.)

The

preparation

of a

data set

for

hydrologic system analysis . . .

LENTON, ROBERTO L., SCHAAKE JR., JOHN C., RODRIGUEZ-ITURBE, IG- NACIO. (U.S.A.)

Potential

application

of

Bayesian techniques

for parameter estimation withlimiteddata

...

McMAHON, T.A., MEIN, R.G. (AUSTRALIA)

Storage-yield estimates with

inadequate

streamflow

data . . .

MARTIN JADRAQUE, VALENTIN. (SPAIN)

Estimation

of

Gumbel law parameters in

small samples ...

MOSS, M.E., DAWDY, D.R. (U.S.A.)

Stochastic

simulation for basins

with

short or no records of

streamflow O’CONNELL, P.E., WALLIS, J.R. (U.S.A.)

Choice

of generating

mechanism

in synthetic hydrology

with

inadequate data ...

PORRAS, PEDRO., FLORES, ALFREDO. (VENEZUELA)

Stochastic

application in ungauged basins for planning purposes ...

ROCHE, MARCEL. (FRANCE)

Homogénéisation

et interpolation

des

données pour un modèle de

simula-

tion ...

SHARMA, H.D., BHATTACHARYA, A.P., JINDAL, S.R. (INDIA)

T h e

use of

simulation

techniques for sequential generation of

short-sized

rainfall data and its application in

the estimation of

design flood ...

VISSER, J.H. (LEBANON)

The

use of stochastic models in a hydro-agricultural development project

inLebanon

...

WALLIS, J.R., MATALAS,N.C. (U.S.A.)

Relative importance

of decision variables

in

flood frequency analysis

WEISS, G. (U.K.)

Shot

noise

models

for synthetic generation of multisite daily

streamflow

data ...

WOOD, ERIC F. (U.S.A.)

Flood

control design

with

limited data

- A comparison

of the classical andBayesianapproaches ...

TOPIC I.3B - THE USE OF SIMULATION TECHNIQUES ESPECIALLY DE- SIGNED FOR DATA-SCARCE AREAS. THE USE OF MATHE- MATICAL MODELS.

POINT I.3B - UTILISATION DES TECHNIQUES DE SIMULATION SPE- CIALEMENT ELABOREE POUR DES REGIONS OU LES THEMATIQUES.

DONNEES SONT RARES. UTILISATION DES MODELES M A -

V

NASH, J.E. (IRELAND) GENERAL REPORT BERNIER, J. (FRANCE)

Données

inadéquates et

modèles mathématiques

de la pollution en riviere

COOK, SAMUEL P., MBURU, SAMUEL

G.

(KENYA)

Regional groundwater

recharge estimates via meteorological data ...

DELLEUR, J.W., LEE, M.T. (U.S.A.)

A

rainfall-runoff

model based

on the

watershed

stream

network

...

HANN, C.T. (U.S.A.)

Monthly streamflow

estimation from limited data ...

KOREN, V.I., KUTCHMENT, L.S. (U.S.S.R.)

Obtaining

deficient

information

by solving inverse

problems

for mathe-

matical

runoff models ...

ROFAIL, NABIL. (EGYPT)

The mathematical

model of

water

balance for data-scarce areas ...

VILARO, FRANCISCO., CUSTODIO, EMILIO. (SPAIN)

Data

acquisition and

methodology for

a simulation

model

of

the Llobre-

gat

Delta (Barcelona, Spain)

...

While the need for hydrological and meteorological data of many types for the design of water resources projects is obvious, it is often found, especially in many developing countries, that such data are either lacking or inadequate.

Recognizing the existence of this problem, the Co-ordinating Counci*l of the I H D appointed a group of experts (third session, Paris, June 1967) to study the problem of design of water resources projects with inadequate data.

Similarly, the Commission for Hydrology of WMlO (third session, Geneva, September 1968) established a Working Group on Hydrological Design Data for Water Resources Projects to prepare guidance material on this subject for the WMO Guide to Hydrological Practices and to maintain liaison with the IHD group of experts appointed by the Co-ordinating Council.

As a means of taking stock of the work carried out by the hydrological community in coping with project design with scarce data, Unesco and WMO jointly convened a symposium on this subject. The Symposium was organized with the co-operation of the IAHS and the Spanish National Committee for the IHD and was held in Madrid from 4 to 8 June 1973 at the invitation of the Government of Spain.

The Madrid Symposium concentrated on the methodology of hydro- logical studies for water resources projects with inadequate data and on current practices for the assessment of design parameters.

The Minister of Public Works of Spain opened the Symposium at the Palacio de Exposiciones on the morning of 4 June. Addresses were given by Dr. Dumitrescu on behalf of the Director-General of Une,sco, Professor Nemec on benalf of the Secretary-General of WMO, Dr. Rodier as President of IAHS and by Dr. Briones, on behalf of the Spanish National Committee for the IHD.

The Symposium was atteneded by 480 participants from 77 countries.

The technical programme, detailed in the Table of Contents, included consideration of 3 major areas:

1. Methodology for hydrological studies with inadequate data;

2. Current practices in different countries;

3. Relation between project economics and hydrological data.

Each area was further sub-divided into topics for each of which the

individually contributed papers were abstracted into a general report,

orally presented by an invited expert, and followed by discussion.

This volume of proceedings was compiled by the Spanish National

Com-

mittee for the

IHD;

it includes all the general reports and individual papers presented at the Symposium, as well as the discussions.

It

is issued as a joint U n e s c o / W M O / I A H S publication

in

the spirit in which the three Organizations have collaborated during the I H D .

Since the individual authors did not present their papers orally at the Symposium, the papers are reproduced here in the order

in

which they are discussed in the general report for each topic.

Unesco,

W M O

and I A H S wish to record their thanks

to

the Spanish National Committee for the

IHD

for the m a n y contributions of its m e m b e r s towards the organization of the Symposium, and for the Committee's as- sistance in the publication of these proceedings.

I1 est évident que, pour élaborer des projets d’utilisation des ressources en eau il est nécessaire de disposer de données hydrologiques et météoro- logiques de types très divers; or il apparaît que ces données sont souvent inexistantes ou insuffisantes, notamment dans beaucoup de pays en voie de développement.

Conscient de ce problème, le Conseil de coordination de la DHI a créé, lors de sa troisième session (Paris, juin 1967) un groupe d’experts chargé d’étudier

les

moyens d’elaborer des projets d’utilisation des ressources en eau sans disposer de données suffisantes.

D e son côté, la Commission d’hydrologie de l’OMM a constitué à sa troisième session (Genève, septembre 1968) un groupe de travail sur les données hydrologiques nécessaires à l’élaboration des projets d’aménage- ment des ressources hydrauliques; ce groupe de travail a été chargé de formuler des recommandations destinées

à

figurer dans le Guide OMM des pratiques hydrologiques, et d’assurer la liaison avec le groupe d’experts de la DHI créé par le Conseil de coordination.

Afin de faire le point des travaux accomplis par la communité hydro- logique en ce qui concerne l’élaboration de projets pour lesquels on ne dispose pas de données suffisantes, l’Unesco et l’OMM ont décidé de réunir conjointement un colloque consacré

à

cette question. Ce colloque, organisé avec la collaboration de 1’AISH

et

du Comité national espagnol pour la DHI, s’est tenu

à

Madrid en juin 1973,

à

l’invitation du gouvernement es- pagnol.

Le colloque de Madrid a traité en particulier de la méthodologie des études hydrologiques sans données suffisantes et des pratiques courantes utilisées pour l’évaluation des paramètres de calcul.

Le colloque a été ouvert par le ministre espagnol des travaux publics, le matin du 4 juin, dans le cadre du Palais des expositions. Des allocutions furent prononcées par M. Dumitriscu, au n o m du Directeur général de l’Unesco, par le professeur Nemec, au n o m du Secrétaire général de l’OMM, par M. Rodier, président de I’AISH, et par M. Briones, au n o m du Comité national espagnol pour la DHI.

480 participants, venant de 77 pays, participèrent au colloque.

Le programme technique, dont le contenu détaillé figure dans la table des matières, portait sur trois domaines principaux:

1. Méthodologie des études hydrologiques sans données suffisantes;

2. Les pratiques courantes utilisées dans différents pays;

3. Relation entre les données économiques du projet et les données

hydrologiques.

Chacun de ces domaines était subdivisé en thèmes, et sur chaque thème un rapport général synthétisant les communications individuellles était pré- senté par u n expert, puis suivi d’une discussion.

Les Actes du colloque, établis par le Comité national espagnol pour la

DHI,

comprennent l’ensemble des communications individuelles et des rapports généraux, ainsi que le compte rendu des débats auxquels ils ont donné lieu.

Ils

constituent une publication conjointe de l’Unesco, de

l’OMM

et de

I’AISH,

reflétant l’esprit dans lequel les trois organisations ont col- laboré pendant la

DHI.

C o m m e les communications individuelles n’ont pas été présentées ora- lement par leurs auteurs, elles sont reproduites dans l’ordre où elles sont apparues dans le rapport les concernant.

Unesco,

l’OMM

et 1’AISH tiennent à remercier le Comité national es- pagnol pour la

DHI

d u concours qu’il a apporté

à

l’organisation

du

colloque et à la publication de ses Actes.

UNEXPLORED B A S I N S

GENERAL REPORT

Prof. A . A . S o k o l o v

The netv~ork of !yyi;lr;rolugioaì 3bssrvations efist:Ag at present represents a discrete field of points ivhioh refleots only approximately the *:onstant variations of hydrologioai e l m e a t s in space and time.

A s quite truly notetl Fierre Dubreuil in his report ("the problemi

af

t r a a f e r of data from observations on

a

point to one or emother area and their dissenclnation on territories and subjeots where no observations wero onrried out, has always been. and is n q one of the central problems

of hydrologf.

This problem is erspecdally important for developing countries where the network of hydrologioal stations is still hadequate and the existing series of observationa too brief(ehort).

But wen in developed countries v:ith a well organieed and sufficiently dense network

of

statione and

is, and always will be/ a great number of water bodies (or regiodor! whose regime not enough light is thrown by obsemstion data, as a nwnbre of middle- sized, and espeoially small water bodies, considerhg their great qurntiQ, pnill always be examined only selectively.

posts, having operated Por a long time, there

In the Soviet Unior, f o r eYaqle,accordhg to data Prom detailed inventarication(2) are numbered about 150 O00 rivera with a length Of more than 10 h(and

if

ne inolude the shortest rivers with a l e n w b a l m 10 h, their total number will aminit to 2

960

O00

)

and about

40

300 l s k e ~ with an area erneeding

i

square h(?:iùif lakes with an area of less thsa

1

sq.km are

boluded,

their total number amounts to

2

850 o00

).The

permanently operathg referenoe network of hpirologioal stations inoludes

2

ebout 6200,and the meteomlogioal network more than 10.000 observation points.

The task of hydrology

- ^as

^{a soienoe}

-

^oonsiate

^h

establishing,

on

the basis of a selective stuty of water subjects, natural laws of the hyilfolcgioal regime and the distribution in spaoe of its ohaxeoteristios, nllowing with a suffioient reliability and preoiwneea neoessaay for praotioe, to spread hydrologioal data to subjeots or regions with

a

soarcity or

the absenoe of hydrologioal data.

Here

we would like to refer agaiii to the already mentioned report tnf Fierre Dubreuil whioh stresses that the most important in the problem of transfer of hydrological data to unexplored basins is the analysis

anä

atuày of the laws of the influenoe of natural and anthropogenous faotors on water regime aad water balanoe, in the establishment of qualitative and quan.t;it&e relations "Hydrology

-

environment". The author of the report notes that the applioation in the computation of the flcod flow and of other elements of

~ d r o l o g i o a l reg- Qf numerous empirio formulae, determined for certain natural oonditions in other regions with different conditions, often results in g o s e errors and misoalculations.

The transfer of hydrological data to unexplored basina(regiœna)

is

direotly or indirectly relnted to the methodology of mapping the oharaoterietioe of the 4drological regime applied in hydrology, since t h e praotioalwcyra and

man8 of such tranefer are generally baeed on the mapping of oharaoteristioe of the hydrological regime and ita parr reters.

"mo basic methods of dissemination(transfer) of hydrolngioal daea on mexplored basins(regions) are used with the aid of mapa:

1) Drwiilg

of

maps of isolinesi 2) Division of a territory into regions based on the

uniformity

of hydrologioal cha-e.oteriat$oa of the regime and

its parameters.

The prinoiple of the method of isolines is the assumption of the presenoe in ths nature of a smooth, colistant chenve of the oharaoteristiorr of the hydrological regime in space,froin one point to another. The division into regions, on the oontrary, proceeds from the assuqtion "IIomogeneity"

of larger or smaller territories end O€ 8 sudden, spcqmodio ohange of the characteristios of the regime between one region and another..

In

the publications on hyckology these h o methods of geographic generalization are often opposed to one another. The appearanoe OC.& critioal attitude ooncerning the method of isolines proceeds from the fact w th the development of t h e study of s m l l basins more and more faotors(data) are in contradiction with the m o t h e s i s on which this method is baaed. The smaller the river basin, more tho oharacteristics of its hydrologioal regime may differ from the meaning of the isolizes wì-ich suppose their smooth change throughout the territoryo

thaf

--

To this o m be given a greaf number 3f exnrnpleao In the USSR, or the territory ssturted on the left bank of the Volea, for instanoc, two small basins louated side by side (1OC-200 8q.h.) have a mean many-years spring flow of

27

and

97

mn, while on the map of isolines of the mean depth of the spring

flow,

at this place is shown

an

isoline of

6ûnnn.

"aturally, the question arises: w h t indioate isolineat what is their sigriificanoe and their m e m i n g

if

the runoff of actual basins deviates so much from them?

In our

piiblications

(3,u

are examined the reasons of the oontradictory opinions on the effioienoy of the utilization of the method of isolines and of the method

OP

division into regions. They are oauaed by

a

misunderetandhg and

an

oppesition

of

the z o n a l i w ( m o t h variations) and the eronali-&(sudden, looal deviafiole)

in

nature.

In

our opinion

sonai

and asonal 1-8, as well as the method8 of mapping based on them

-

methods of isolines and of division

by

regione, do

not

but mutually oomplete eaoh other. The first (isolines) shows the general,

zonal law#

00 distribution of the characteristios of hydrologioal regime through the territory of closed basins( ooinoidenoe or a small difference of $be aurfaoe and

the eubsurfaoe

nater divide), dieplqred in the

murse of &ir

averaging for large areas, for whioh

the

influence of azonal(looa1) factors

of the

environment o m be disregardedzThe seaond. permits to

reveel

the

kiternaï,

disorste

by

its essenoe, structure Of' these avoraged oharaoteristioa,

4

conditioned by the influence of local f w t o r s

-

geological struotures, slopes, vegetation, spi1 and grounds, which constitubo the surface of

tho

basin, a d . others a

i

ûno of the rundamental proTLsions of the theorj of hydrological m q p i n g and of the applioation of t h e method

of

extrapolation

of

data on unexplored basizs by means of maps of io3linesS cor.8ists in tha fact that the data uaed

in this chse, concern basins complying with the condition:

-

A ~ A ( A

ma^

(

1)

whsre

A -

^mean value of optimal areas OZ the catchment in which is telerated the interpolatcion :o hydrological characteristics by m a n s of isolineai A 6,

A max -

respecti/vely the lower and the upper limit of the catchment

area, whose d a t e are unsuitable for drawing m p a of isolines.

Only relation

o

those basins wiiich comply with the condition(I),the goographical Iritqrpolation is parrrlssible and, consequently, the hypoaesis O?

a s m o t h and omstant rwiation of tho oharnoteristics of the hydrological reLi-ie on tho terr%toFj is correcto

f

In

the oatoi-wnt w e a s r w g i n g from

O

to A nLio are found other laws. They ar+ l.aClected in larger or mallsr deflections of the characteristioe

of

the

ruioff of

small

rivers fro,^ zonal(ssa the abova exainple i>f

27,37

arid 6ûmi)inevitably everrrged and as if liberated from the influonoe of the local factorsíspecificities oí' the environment, according ti,

P.

hbreuil). Chinlg to the fa& that

in

small basins individual peculiaruios of the conditions of the runoff of

snow

melt and rainfall plow are

s h a m most

sharply(for example, the g m m d o," one basin ia made of ~and,oi' another

-

^of

^olay,

or one basin is

open,

another has a forest cover, etco) the data

on

the runaff of these basins generally are not suitable for

a

geographioal awmarizing with mags

of

isolines. With the decreaae of the size of the ce.%chment increases the probabili% of the defleotions, as well as their importanoeo

The above oan

be

illustrated by a scheme of defleotions o? the mean annul runoff(for m m y years) of karat rivers from Its zonal significapoe in relation to the area of the oatchment(fig.1) .These "fork-shaped" shhemes of deflections can be disclosed also in study%ng the iliflwnce of othar Pactors(for example, the dekreb of afforestation) on the runoef a d their relatione

to

the dimension of

of the o.ztohment.

Th oqiplltation of these dsfleotiona is owried out by

P mane

of g e m t i c rdlatiora of the charaoteristioa of the hy.itrologioal regime pli* the faotors

LieteriliQ tham by the lntroduotion of oorrection factors in t h ~ zonal oharaoteris- Lics sf the hydrologioal regime, obtained for the uriexplcred'bssina tlrougk- the

m q ~ S of isolines.

Y!ie principles of oomputation of the main oharcoterietios of water

resources in the absence or scarcity of )Ij-1romtrioal drrta, based on the above eox:al ari e.zo-ml geographioal laws of $he rtmDff, ar9 examhed with m r e tietails in the rop0t.t o f

R o f

K.P.Voekresendqr(5)

In the light

of

the atom, tht> oonolusion drawn in the report of I.Bdek(e;

euòmitted to t h 3 present Symposim, beco*:es olear end convincing, nariiely, that the defiliition of reference hy4rologiaal charaoteristios for mexplored sub jecte

(regions)only on the basia of data from r-jpreaentativa and experimental basins, c w n o t be ~ e o o m a d e d , i.e. it ie not possible to transfer direotly data

Prom

7bswvations on 8-1 catoinnents tr, unexplored large basine.

The author of the report, analysing the data on experimental and represat- ativu basins of fropioal

Mrioa,

where under

the THP

programe were created m r e than 100 represantativ

StUdy(8nalya~s)dfdata from experimental and representative basine

and

of those Prom the standard network

is neoesomy.

The differenoe between the charaoterietios of the runoff, obtained on small experimontai catchumts and aidlar characteristioa o? the b a s h of a standard netmork, should be carefully analysed.

d experimental basins, brawe the ooaoluiona that a joint

+

Considering

the

influace of fc-eats on the runoff on the basis of dooumente from experimental investigationa ia

X q a , ;r.Balak

d r w s the conoluaion that a bamboo or

a

high mountain forest reduoes the surface runoff a t h a t the replaobanent of forests by aEricultural

farm

inoreases the voliono

of

the runoff. Transevaporation from forest vegetation mas three times higher than that from aeac;onl;r subnierged fields.

With the increase

OP

tho 'egrje c? boggiilp;, accorahg to data from o b s e r vations in the basin of the river Ilafou, the annual runoff deoreases.

in

this oonna-

ctiori, 7.Balek underlines that m r a attertio- should bo drawn 'to h y ~ o l o y ; y of tropical mmps, as these wrsnps play an i:pcrtoil-t role in ti-9 foranation of the river r m o f f

6

At ths same time he notes that the methods of oomptation of the nuirf8 usad at present in the temperate climate should Se revised taking into aooount the specific oonditione of tropioal oatohrnents.

In the report of VbS. Vuglinsw and

V.A. se?mmv(fl are

atudied the specificities

of

formation and the methods oî .h.anefer of data from observa- tions to unexplored basins si' the runoff in mountain are-, including the conmody utilized method of d e t e d n i n g the standard of the annual runoff, based on the establishment of regional relations of

the

npdulua of

the

annual runoff to tho height of the uatchment, aooording

to

data from explored bas ias

The

authors note that,pthe computation of the runoff of small oatch- -.axts t h utilization of

the

relatlon

of

the nodulus of

ruroff

to tho height of tho catohment obtains not always satisfaatory resdtte, whio-h can be

explained by the kifluence of looal faotors in the mouutains~

In

this relation oatchments with the same altitude 0811 differ ccmsirlerably by the conditions of their formation, as well as by the volun.3 of the ennual runoff.

In suoh cases the auL,hors recomnend to determine the standards of i k i

annual runoff of mountain catcbments witi sufficient or exoessive misture, by m e a u

of' a

joint solution of

tho

equation of the sate- and heat-balanoe.

Tile runoff is oaloulated bj the differenoe between preoipitation and m p o - transpiration. The definition of the Etasdard annual preoipitation is oarried out with the applioation

of

graphs of the relation of preoipitationa with the altitude, taking into a m o u n t the crogaphio speoifioities of the m e a r

i.mre preoi

TT

e equation of

&

ï b h d y k o # nihioh takes into aooouut

the

turbulent heat exohange th3 baaio paramatera of mhioh are

:

radiation bCbhaOe, precipi- tation and turbulent heat-exohange.

oniputation of the etandexde

of aruiual

evaporation is made by

a

The above s o h e m of computation is used for catolnnents looated in the lower and middle

mmtein

bolts.

be used also, but

ki this o w

the number OP terma

of the

water bcilanoe For the higher

iiiomrtaine

this method oan equation i8 Fnoreased(it

i

ta oaïouïata the

volume

of glacier6 ablation, Qf anow pa& melt and a dietinot oeïoulation of evaporation from

lr

various underlying surfaces of the high m u u t a i n s ~ o

In this report are also studied the methoCs of oaloulation of the coeft'ioient of variability of t h e annual ruuof'f

-

^{Cv, ueed}

ⁱⁿ

^momtait~

ter ri to i- ies

In the report of the group of authors:

ML

Albitlet, G. Castany, Mpe

Delaroziere-Boulllin,

R.

Jonac et G. &-gat(B) is exposed the method of appraisal of the &mers1 water resoiiroos(equstsd by the authors to the mean m u a l r-uiorf) anci the renmable groundwater resources with inadequate data. used by th93 authors for the territory of Franca and Venezuela.

The authors recomiiend to determine the general water resourcss(Ptreamf1m) '51~ means of maps of isolines of preci;>itatkon &Td evapotranspiration, by the

?ifference precipitation minus evepotransporation calculated by ths method scpares. ìVhm there is a grmi.

t

W f e r e n c e of the factual evaporation,obtained

> y the differeroe precipitatior? minus runoff in a looked discharge seotion line mid evaporation, calculated by ti- method of Thornthwaite or Turc, a oorreotion coeri'icient is introduced C, by means of irhich the map O P the rateu evaporatào.on 13 cor reoted.

Thornthwalte or Turc. Th3 value f these differancea are dotarmined by conventional

yhe authore determina the na%iiral resources of groundwaters far the smis squares of the map as the volume of t h a goneral runoff by moans of

"Geological coefficients" de%i,eci as a portion o f the unclergound flair in the generai river ~ f f i

'fl.is approach to th?: cle.:iriitiov of the volurm of renewed resourods of groundwaters is also utili.eed in the ':SSt? in the publioations of B.I.Kudolin a n d o.v.Fopov(9)

The method o? computation of the total runoff by m e a m

,>P

the difference 3recipi :.ation minue evapotranapii.ution arid ths 3ef inition, ori tYAs basig oí' the so-. ..allad " C l h t i o rUnoff",recomnan<ied b;r the authors as in ths preoeden% report, h a s baen used ?or R lon; t h e , ( h p a r t i m l m it was applied by id.I.L'vovitch

in

1945

in his work"E1emnts o" w a L x regirno of the rivers of the Earth"(lo), but it has seriocs limitationso More or less acoeptableyare obtained r sults by this