WORLD METEOROLOGICAL ORGANIZATION
COMMISSION FOR HYDROLOGICAL METEOROLOGY
ABRIDGED FINAL REPORT OF THE FIRST SESSION
Washington, 12-25 April 1961
PRICE: Sw. 4.-
I WMO - No. 105. RP. 45 I
Secretariat of the World Meteorological Organization - Geneva • Switzerland 1961
CONTENTS
Page List of representatives attending the session v Agenda VIII General summary of the work of the session I. Resolutions adopted by the session 16 Resolutions' Final Session No. No. 1 3.1/2 Working Group on Hydrological Forecasting 16 2 3.2/1 Working Group on Network Design 17 3 3.3/1 Working Group on ~lbllcation and Exchange of Data for Hydrological Meteorology 17 4 3.3/2 Transmission of precipi tat,ion data 18 5 3.8/2 Working Group on Terminology 19 6 3.10/1 Accuracy of measurements as required for hydrological meteorology 19 Annex - Accuracy of measurements as required for hydrological meteorology 20 7 4.2.2/1 Working Group on Instruments and M~thods of Observation 21 8 5.2/1 Working Group on Hydrological Design 21 9 5.2/2 Working Group on Guide on Hydrological Meteorology 22
Recommendations adopted by the session 24 Reoommendations
~ Session ~. No. 1 3.1/1 Bibliography on Hydrological Forecast·ing 24 2 3.1/3 fl'ransla-c:!.on of valuable publications on hydrological forecasting 24 3 3.1/5 Rapid exchrulge of information required for hydrological forecastlng on internatJonal rivers 3.5/1 Climatic maps for hydrological purposes 25 An.'1ex _ Special climatic maps for hydrologists 26 5 3.'(/1 study of seic.hes 26 6 3.5/1 International Meteorological Vocabulary 27 7 3.9.1/1 Radar observatlons of precipitation 27 8 3.9.2/1 Influence of land use 28 IV CONTENTS
Recommendations (continued) Page Final Session No. No. 9 3.13/1 Organization of meteorological and hydrological ·services 28 10 4.1/1 Regional association activities in hydrological meteorology 29
Annexes I Annex to paragraph 3.8 of Qfmeral Summary Short list of hydrologic te"ms II Annex to paragraph 5.2 of General Summary Outline of Gui4e on Hydrological Meteorology
List of documents 36 W 0 R L D MET E 0 R 0 LOG I CAL ORGANIZATION
Supplement to mao Publication No. l6l.RP.59
Decisions of the Executive Committee on the Abridged Final Report of the Second Session of the Commission for Hydrometeorology
This document is a supplement to mm Publication No. l61.RP.59 - Abridged Final Report of the second session of the Commission for Hydrometeo rology - and should be considered as a guide to the status of the decisions adopted at the session.
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* - 3 -
A. DECISIONS RECORDED IN THE GE]\fERAL SUJ"Il'iIARY OF THE WORK OF EC-XVII
5.3.8
5.3.8.1 The Executive. Committee noted with approval the report of the president of CHy. It decided that the matters referred to in this report "QuId be disoussed in connexion with the oonsideration of the report of the second session of the Commission for Hydrometeorology and the report of the EC Panel of Experts for the International Hydrological Decade.
5.3.8.2 The Ccmmittee examined in detail the report of the second session of the commission. and the main conclusions of' the Committee are embodied in Resolution 12 (EC-XVII). With regard to Recommendation 1 (CHy-II) concerning the adoption of certain technical regulations in the field of hydrometeorology, several members of the Committee considered that- this question -was not of great urgency and could therefore be postponed until F'ifth Congre s's;' It was also pointed out that there was no unanimous agreement on the riecessity for IDIO .to include this material in the Tec'hnical Regulations at th~ present-tim'" .and. that the text pro posed by the commission would b,? more appropriate'for inclusion in the W/JIO Guide to IlYdrometeorological Practices. "On the other hand, other members drew attention to the great importance of standardization of procedures irihydrometeorology at the beginning of the International Hydrological Decade and that therefore urgentac tion was needed to have the proposed Technical .Regulations adopted by v/lilO. In conclu'sion the Committee decided that the annex to Recommendation I (CRy-II) should be circulated to, ~~embers of W/iIO for urgent study. The comments of Membe:rs 'should be examined by the CIlY Working Group on Guide and Technical Regulations with a view to submitting proposals on this subject to the eighteenth session of the Executive Committee.
5.3.8.3 With regard to Recommendation 4 (CRy-II) the Committee considered that, al though the co-ordination of meteorological and hydrological activities at the national level is essential, IDm should not advise lVlembers on how to organize these activities. The Committee, therefore, did not accept. RECOMMENDS (3) of Recom mendation 4 (CIlY-II). furthermore, theCommi ttee decided to change RECOMMENDS (2) of this recommendation and these conclusions are incorporated in Resolution 13 (EC-XVII}. The other recommendations of the commission were adopted without comment. ...: 5 -
:!:~E~~E~J!!::_~~.!§ In view.of the aotivities of··the UNESCO· Co-ordinating Counoil on the Ques~ion of Translation and Publication of Technical Papers on Hydro meteorology, the Committee deoided to· take no further action on this subject at the present time.
:!:~E~~::~E!;_~~.!2 'Phe Exeoutive Committee requested the Secretary-General to consider further the possibility of including training in hydrometeorology at meteoro logical training centres and to co-ordinate this action with the United Nations Regional Economic Commi",sions and wi th U1~ESCO.
~~E~~E~J!!::_~~.!!2 The Question of symposia and seminars was considered under agenda items 5.2 and 4.1.
:!:~E':':~E~l2!;_E.!:!:.:!:. The Committee requested the Secretary-General to examine wa;ys and means of bringing the relevant ,INO pu1l1icati(}n~to theattenti·on-of hydrologists.
!:~E~~E~E!::_!~.!!:t This Question was considered under item 4.
:!:~E~~E~12!::_E~!2 'Phe Committee requested the Secretary-"General to bring the. Question of the ·need for regional co-operation in hydrometeorology to the attention of the presidents of regional associations, - 7 ...
Recommendation 4 (CRy-II) - Organization .of hydrometeorological activities in ------~~------dIfferenr_coUntries--~~------~------~ Decides to adopt this recommendation in a modified form (see Resolution 5.3.8/2).
Recommendation 5 (CRy-II) - Collaboration with the United Nations and its ------~~-~~~-----~------T-~--~--~--~~~~------~-~-~--~-----~~-- . reg~onal___ ~_~ _____ economic ~ ____ ~_~ commissiohs ___ ~ _____ ~1~~_~ and __paragraph ~~ ______13· _ of. the General Summary -~------~-- (a) Approves this recommendation,
(b) Direots the Secretary-General to :
(i) bring it to the attention of the United Nations and the regional economic commiss_ions conce:rned, and (ii) take,as far as practicable, necessary measures for implement ation of this recommendation~
~~~~~~~~~~!iO~_~_i£~l:!!2_=_~!~~~!~~_~~R~_!z~_~r~~~~!~~~~~~~r (a) Notes this recommendation,
(b) ReqUGsts the presidents of regional associations to arrange for its implementation.
Recommendation 7 (CRy-II) - Re"Vision of resolutions of the Executive Committee ------~~~~~=~~=R~~~~~~s_~~~~~~~~~~~~~~~=~!=~~~=~~~~~~~~~~ !z~_~r~~~~!~~~~~~~l (a) Notes this recommendation,
(b) Incorporates the substance of this recommendation in the Executive Committee resolution on revision of past Executive Committee resolutions. V
LIST OF REPRESENTATIVES ATTENDING THE SESSION
1. Officer of the session M.A. Kohler president
2. Re(2resentatives of Members of WMO F.J. Lacaze delegate Argentina A.F. Rainbird principal delegate Australia D.N. Body delegate L.J. Tison delegate Belgium J.P. Bruce principal delegate Canada R.H. Clark delegate M.F. Ebert principal delegate Denmark H. Simojoki delegate Finland P. Fontaine principal delegate France A.R. Durget delegate Ph. Picq delegate G. Remenieras delegate J. Rodier delegate W. Friedrich principal delegate Germany, Federal Republic S. K.Ghose principal delegate India R.C. Shenoy delegate P .M.A. Bourke principal delegate Ireland M. Gilead principal delegate Israel M. Jacobs delegate U. Mane delegate Y. Taji-Farouki principal delegate Jordan Chin Myun Kim principal delegate Korea, Republic of Chung Sup Shin delegate W. Bleeker principal delegate Netherlands L.J.L. Deij delegate A. Volker adviser A. Jakhelln principal delegate Norway J. Lambor pd.ncipal delegate Poland R.M. Romaih principal delegate Saudi Arabia H" Da.l'deer delegate A. Seraj delegate A.A. Sallh prinCipal delegate Sudan G.!.. Nybrant principal delegate ·Sweden E. Walser principal delegate Switzerland S. Vesa-Raj anan principal delegate Thailand D. Chareonsook delegate A. Kurun principal delegate Turkey VI LIST OF REPRESENTATIVES
V.I. Korzun principal,pelegate Union of Soviet Socialist V.A. Uryvaev delegate Republics E.G. Popov delegate V.D. Moslov delegate S.A.M. Hassaneln principal delegate United Arab Republic S. Kadourah delegate R.H. Clements principal delegate ·United Kingdom of Great F.R. Allen delegate Bri tain and Northern Ireland A. aleasdale delegate R.P.W. Lewis delegate W.E. Hiatt principal delegate United Statas of America R.W. Carter delegate A.W~ Johnson delegate M~A. Kohler delegate W.B. Langbein delegate H.O. Ogrosky delegate F.-F. Snyder delegate W.W. Sohl delegate H.C. storey delegate A. Michelangeli principal delegate Venezuela R. Convit delegate
3. Observers a) InieE-QoyeEn~ent~I_OEq~nlz~t!ons_ E.S. de Breuvery United Nations R.C. Dawson Food and Agriculture Organization of the United Nations E. Erikson International Atomic energy agency H.R. Shipman World Health Organization A. Martinez Economic Commission for Latin America
b) QtheE Qr~'ni~aii~n~ E. Smith American Geophysical Union A.C. Orvedal International Society of So11 Science L.J. Tison International Union of Geodesy and Geophysics S. Vasa-Rajanan Pacific Science Association D. Chareonsook Pacific Science. Association J. Rodier Scientific Council For Africa South of the Sahara W.A. Liddell World Power Conference
4. ~. P,H. Kutschenreuter president, GSM
5,. Conference Secretariat
K. Langlo executive secretary WMO Secl'etariat LIST OF REPRESENTATIVES VII
Conference Secretariat (Cant.)
O.M. Ashford technical secretary WMO Secretariat P.I. Miljukov WMO Secretariat
6. Secretariat of the session
T. Maddock Jr. J.L.H. Paulhus C. Dunham M.J. Scanlon
/ VIII
AGENDA
Agenda Relevant item Documents No.
1. Organization of the session 1.1 Opening of the session 1.2 Consideration of the report on credentials Adoption of the agenda It Rev. 1, Add. 1; 2, Add. 1, 2, 3 1.4 Establishment of committees
Report by the president of the 15, Add. 1; 55 commission
Technical questions Hydrological forecasts 4·38 lB'' 31; 36; 1 1,2,3 3.2 Networks for hydrological 19; 24; 2B; 36; 2 meteorology 57 3.3 Publication and exchange of 20; 22; 35; "3,4 data 46, Rev>. 1 3.4 Analysis and pUblication of 25, Corr. 1, data on flood-producing storms Add. l', 32; 33; 47 Content of climatic atlases with 7·, 58 4 respect to water reSOUrce development 3.6 Avalanche warnings and forecasts 23, Add. 1, 2', 29; 48 study of seiches 26; 49 5 Standardization of terminology, 16; 59 5 6 codes -and units Recommendations adopted at the 7,8 Nairobi Joint Symposium on Tropical Meteorology in Africa Radar observing systems 9; 54 Influence of land use 8; 56 3.10 Accuracy of measurements as 10; 50 6 required for hydrological meteorology 3.11 Evaporation measurements and control AGE N D A IX
Agenda Relevant item DOGumentc. No.
3.12 Meteorological factors in 21; 41 hydrological design 3013 Organizational structure of the 27; 51 9 hydrometeorological work in different Gountrle" 3.14 Hecommendatlons adopted rlt the 30; 60 First Inter-African Conference on Hydrology
4. VLo.£kinq relations ',dth regional iUiG.od.ations ,. other techni-c.l.ll GQJUmis::d.ol1s J.nd other intern
International As~~ociation of 5; 45 Scientific Hydrology (IUGG)
5 General questions 5.1 Drafting of technical regulations 12; 52 for hydrological meteorology 5;02. Preparation of international guide 13; 63 8,9. on hydrological meteorology 5G3 International seminars and symposia 14; 64 5,,4 Establislunent of working groups 61 5~5 Election of officers 62 5a6 Date and place of the second session Clarification of the terms of 42 reference of the cormnission
GENERAL SUMMARY OF TIlE WORK OF DiE SESSION
1. ORGANIZATION OF DiE SESSION
At the invitation o.f the Government of the United States, the first session of the CQnunission for Hydrological Meteorology (CHM) was held in Washington. D. C., from 12 to 25 April 1961. The meeting took place in the International Conference Suite of the State Depart ·mentBuilding, where new and excellent conference facilities and experienced conference staff were at the disposal of the conunission. Simultaneous interpretation into English and French was provided both at plenary meetings and at the committee meetings. There Were 68 participants at the session. These included representatives from 27 countries and nine international organizations. TM representative of the Secretary-General, Mr. K. Langlo, was designated executive secretary; and the· WMO Secretariat was further repre sented by MT. O•. M. Ashford and Mr. P. I. Miljukov (permanent secretary of the CHM)~ A com plete list of participants is given at. the beginning of this report.
1.1 0Reningof the session (Agenda item 1.1) The president, Mr. Max A. Kohler (U:S.A.), opened the first session of the Commission fcir Hydrological.Meteorology at 11.00 a.m. on 12 April 1961. Theme~ting was addressed by !.!.r.Walter G. Whitman, Science Advisar to the Secretary Of State of thE> United States. In welcoming the delegates to the session ; MT. Whitman stresse.d the international nature of pure science and of many of its applications. By discus sing the technical questions before them as professionals and individuals, delegates could contribute to tM solution of difficult international problems of water resources before tM issues become emotional political disputes. Mr. F. W. Reichelderfer, Chief of the· United States Weather Bureau and Permanent rep resentative of the UnHed States to tM WMO, jOined in. the· welcome. expressed by Mr. W. Whitman. He ·rilferr"d to the growing emphasis throughout the world on geophysical sciences, stimulated by the International Geophysical Year. Hydrological meteorology was in the fore front of theSe developments and efforts were being directed to the solution of many import ant probleins,- such as the means of achieving better use- -of water i1;1 arid regions and of con'" trolling floods in other areas. It waS fitting that WMO had revitalized its hydrological activities by establishing CHM. One of the first tasks of the new commission was to clarify and (strengthen its aims and functions .. Addressing the session as representative of the Secretary~eneral of Wi'vIO, Mr. K.. - Langlo outlined the ,;81e of the technical Commissions, the work of which depended largely on the- voluntary- efforts of the experts nominated by Members t.o seTve thel'eon~ On behalf of WMO he thanked the authorities who had made it possible to hold the ses sion in Washington where such excellent facilities had been providad~ He stresed that the Secretariat of the session would give all possible as.btance to delegates. in fulfilling their important task, Finally, Mr, Max A. Kohler delivered his presidential address in which he outlined the developm·ents leading up to. the establishment of a WM) commission for Hydrological Mete orology. He stressed the important r8Ie which WilD and the new commission have been called upon to playas a contribution to the common eHort of the united Nations Organizations in terested in water reSOurce development., The president said that in ordex to ful-fil its task the activities of the commission must be vigorously pursued on a continuing basis by small groups of dedicated expertsll. He wa~ convinced that the session would be able to develop a programme for the commission which would contribute significantly to the overall problem of water resOUrce development~ 2 GENERAL SUMMARY
1.2 Consideration· of the report on credentials (Agenda item 1.2) At the second plenary meeting the representative of the Secretary-General presented a provisional ·list of participants which, with some comments, was accepted as the first re port on credentials. It was consequently decided not to set up any credentials committee.
1.3 Adoption of the agenda (Agenda item 1.3) The provisional agenda was adopted at the second plenary meeting without amendment. At its third plenary meeting the commission decided to add item 5.7, Clarification of the terms of reference of the commission. The final agenda is given in the beginning of this re port together with a list of relevant documents.
104 Establishment of committees (Agenda item 1.4)
1.40.1 Two working committees were set up to examine in detail various items on the agenda: ( a) Committee A to deal with questions of essentially technical character. Mr __ W. Bleeker-(j:jetherlands) served as chairman and Mr. P. I. Miljukov (WMO Secretariat) and Mr. J. L. Paulhus served as secretaries of this committee. (b) Committee B to deal with questions of essentially organizational character. Mr. R.H. Clen;ei1ts-\United Kingdom) served as chairman and Mr. O. M. Ashford (WMO Secretariat) as secretary of this committee.
Nomination Committee In accordance with General Regulation 22 a Nomination Committee was established con sisting of Messrs. Sayed A. Hassanin (UAR), Valentin I. Korzun (U.S.S.R.), Armando Ml.chelangeli (Venezuela), James P. Bruce (Canada), A. F. Rainbird (Australia) and P. Fontaine (France) •
Co-ordination Committee In accordance with General Regulation 26 a Co-ordination Committee consisting of the president, the chairmen .of the two working committees and representatives of the Secretariat was established.
1.4.4 Committee on Nomination of Experts for Working Groups ------It was decided to set up a committee to propose names of exnerts to be invited to serve on the various working groups. Ibis coromi ttee was composed as follows: p" M. Austin Bourke (Ireland), S. K. Ghose (India), Mordechai GilMd (Israel), Max A. Kohler (president of CHM), Valentin I. Korzun (U.S.S.R.) and L. J. Tison (Belgium).
2. REPOnT BY THE PRESIDENT OF THE COMMISSION (Agenda item 2)
2.1 The. commission noted with great satisfaction the work already carried out by the president of CIIM and wishes to place on record its appreciation of his excellent leadership.
2.2 The representative of the United Nations stated that the beginning made by CHM ap- peared to correspond to the hopes of the United Nations and the speciali~ed agencies when they had urged WMO to undertake greater responsibilities in hydrology.
2.3 A question was raised how C~l could contribute most effectively to the WMO technical assistance programmes, and it was agreed that the various types of guidance material planned to be prepared by the commission would be of great help to many countries in planning and de veloping their facilities and activities in the field of hydrological meteorology. The com mission wished to call attention to the many deficiencies in such facilities and activities in various regions of the world, and expressed the hope that the regional associations and Members concerned would take steps, possibly assisted by WMO Technical Assistance and the Vnited Nations Special Fund, to remedy such deficiencies. GENERAL SUMMARY 3
3. TECHNICAL QUESTIONS
3.1 Hydrological forecasts (Agenda item 3.1)
3.1.1 Bibliography on hydrological forecasting ------The commission discussed the possibility of the publication of a bibliography on hydrological Jo-recasting. It was realized that there exists already an International Biblio graphy.on Hydrology published by the International Association of Scientific Hydrology of the IUGG. The commission considered that this bibliography, which consists of a collection of national bibliographies and which is intended to be published annually, would be of in creas~d value if arrangements could be made .for an identific«tion of all papers relating to hydrological forecasting- The commission further agreed that Members of V.J1v1.0 that do not sub mit nationLlI bibliographies on hydrology to the International Association of Scientific Hy drology be urged to collaborate, identifying publications on hydrological forecasting. The main decisions reported above are incarpo.-rated in Recommendation 1 (CfIM-I) .. In Gonnexion with agenda item 4,,4 the commission also discussed the WMO subvention to rASH for the International Bibliography on Hydrology. It was agreed that this bibliography was of great value for the work of the commiss:Lon and the hope was expressed that this fact be taken duly intb account when a decision is taken on the continuation and the amount of this subvention for the Fourth Financial Period (1964-1997).
301 .. 2 TIle orgnnization of internatlonal symposia and seminars on hydrological forecasting ---~-~------~------The commission noted the great importance of international symposia and seminars to provide for the dissemination of theoretical and practicrll kno1Nledge in the field of hydro logical forecasting. The recommendations of the commission on this subject are reported un der item 5.3. During the discussion of training semio.ars, the commis!6"ion noted a suggestion that WMJ should give active consideration to the improvement of training facilities at existing scientific institutions by the following means: .
(a) By arranging 'syllabuses and course material relating to hydrological forecasts; and
(b) By traIning instructors at scientific institutions by arranging fOT their participa tion in the work (theoretical and practical) on hydrological forecasting at suitable institutions or organiZations where advanced practices are used and whe"'e demonstra tion facilities are availableo The commission noted further that the Executive Committee would consider the general questlon of meteorological training at its forthcoming session and agreed to request the president of CHM to invite the attention of the Executive COlllmittee to the inadequacy of training of personnel engaged in hydrolog]cnl meteorologyo
3 .. J.,,3 'yea:.:l.!i~a!i~n_o! b.y~r~l~g.!.c~l_f;:r.:.c~s!s The commission decided that verification of hydrological forecasts on an international basis was not warranted at this time.. It was agreed, however, that it would be useful to in clude some features on verification of such forecasts in the planned symposia on hydrological forectisting... Furthermore, the commission decided to request the Secretary-General to carry out all inquiry on national methods of verification of hydrological forecasts currently used,. and to make this information available to Members ..
3 .. 1 .. 4 FOl~uulation of hydrological forecasting requirements from meteorological services
------The comnIission noted that meteorological data, for example on precipitation~ water equivalent. of snow cover, evapotranspiration, air temperature, soil moisture, radit1tion, etc", are widely used in hydrological forecasting~ Hydrological forecasting a150 pliJces demands on meteorological forecasts of certain meteorological elements" The session agreed that the formulation of these requirements constituted one of the main tasks of the Commission for 4 GENERAL SUMMARY
Hydrologic-al Meteorology. However, in view of the complexity of the problem, the commission was not able at-this session to formulate in detail these requirements. The commission there fore established a working group with terms of reference as given in Resolution 1 (CHM-I). It also decided to refer CHM-I/Doc.18 (submitted by Switzerland) and CHM-I/Doc. 31 (submitted by Canada) to the working group for study.
3.1.5 Er~~r~tlon £f_a_t~chnic~1_n2t~ £n_hyd£o!o~i£al fo£e£a~ting ~ni £f_a_chaEt~r_orr ihis !!U£J.~.ci ioE. insl!!.sio!! in_the_G!!.i!!e_t£. !.!y!!r£12.9ic,,1_M~t§.0E.0lo9.Y_ The Working Group on Hydrological Forecasting (see Resolution 1 (CHM-I» was re quested to prepare a technical note which should include descriptions of the maIn methods o-f hydrological -forecasting, -surmnarles of meteorological information required, and a list of some important pUblications on hydrological forecasting. The working gr-oup was also requested to prepare a chapter on hydrological forecasting for inclusion in the Guide to Hydrological Meteorology.
3.1.6 The commission noted that res.earch workers in many countries are handicapped by not having at their disposal translations of valu·able publications in the field of hydrological forecasting. It decided to recommend the translation of some such publications for which there is a substantial demand into at least one of the official languages of the Organization. The commission adopted Recommendation 2 (CHM~I) on this supject.
3.1.7 Ra£i£ 2.x£h~n9.e_of !nfo£.m~t.!.o!2 £.egui.r~d_f.2.r_hyd£.olo9.i.£al iOEe£a~t.!.n9. !?n_i-!2t~r!!aii.2..n~l EiyeEs The commission recognized the need for making available to Members information on existing arrangements for rapid exchange of data required for hydrological forecasting on in ternational rivers. It was proposed in Recornmend·ation 3 (CHM-I) that the Secretary-General shOUld collect such information a-nd distribute it to Mernbers.- The question was raised as to whether it WOUld. be useful also to collect information on systems of internal transmission of data used by individual Members for purposes of hydrological forecasting. The commission agreed that a decision on such additional collection of information could be left to the dis cretion of the Secretary-General. The commission considered that it would be premature at this stage to set up a working group to make a comparative study of the existing sys-tems for exchange of data required for hydrological forecasting. It was agreed,however, to authorize the president of the commission to establish, if necessary, such a working group at a later stage.
3.2 Networks for hydrological meteorology (Agenda item 3.2) 3.2.1 One of the questions considered under this item was the division of responsibility for hydrological networks between the regional associations and the. Commission for Hydrolo gical Meteorology. The commission agreed that the division of responsibility for networks laid down in Resolution 4 (EC-III) should apply also to CHM. This would mean:.
(a) That the field of responsibility of CHM shall be to make recommendations of a general character on the desirabie spatial distribution of stations and the time interval between observations for various purposes; these recommendations should be based on general and scientific considerations and on practical considerations of the accuracy of the observations; (b) That the field of responsibility of regional associations shall be to promote the esb·blishment of networks of specified stations with due regard to the decisions ef Congress and the Executive Committee and to administrative and financial considera tions.
3.202 The commission considered that there was a need for the preparation of guidance material on network design and for evaluation of the adequacy of existing networks. By Resolution 2 (CHM-I) it decided to set up a working group to study these problems. GENERAL SUMMAI1Y 5
The commission considered that some freedom should be left to the working group on network design to decide how much information on present networks would need to be collected by the Secretariat in order to assist the working group to fulfil its task. During the session an effort was made by a sub-committee to establish recommendationtj on minimum density levels of network for measurements of certain par 3.2.4 The commission noted a statement by the representative of WHO that hydrological data over extended, continuous periods aTe indispensable to the work of sanitary engineers confront ed with problemf. of planning, design and operation of sanitiuy works, and to officials charged with the supervision of such facilities .. The commission was aware of the importance of the problems raised by the WHO representative and expresst':!d the hope that the· guioance ma~erial to be prepared by CHM on hydrological networks and forecasting would be of assistance to Vn-JO. The commission decided to ask the president of CHM to bring to the attention of the regional asSO ciations that sanitary engineers may hav-e special requirements with regard to the siting of hydrologicnl stations for the purposes of sewage disposal 3.2.5 The commission exomined Recommendotion 2 (III-fiA VI) and saw no objection to the ap proval of this recommendation. The hope was expressed that ~-Ilembers would collaborate fully in the collection of-information to be cnrried out by the Secretary-General. It was assumed that the report prepared by Regionol Association·VI on hydrological meteorology, as 0 result of the inquiry, would be made available in due course to the president of QiM. 3.3 Publicotion and exchange of data (Agenda item 3.3) 3.381 £UEllc~tion ~ni ~x£~n£e_o! ~a!a_f~r_h1d£o!o~i£a! ~e!e£r~l£9,l It was decided that the problem of publication and exchange of data used in hydro logical meteorology should be examined by a VJorking group estoblished by Resolution 3 (CHM- I) . The commission agreed that this working group should prepare guidance material on collection, processing and pUblication of data used in hydrological meteorology for inclusion in the Guide to Hydrological Meteorology. The commission stressed the need for determining which meteorological data, in pub lished form, are required by hydrologists and requested the working group to prepare a report on this question .. 3~3.2 lr~n~mis~i£n_oi Er~clpit~tio~ ~a1a_ The commission examined a proposal to lnclude in international exchanges in coded form information about the amount of precipitation during the last six hours at all main standard times for synoptic observations. There was general agreement that these data are of great im portance in hydrological forecasting in most countriesG The commission considered it advisable 6 GENERAL SUl,~,1ARY to arrange such exchanges on d regional basis, and decided to request the president of CHM to invite the Commission for Synoptic Meteorology to investigate the practicabilIty of intro ducing such exchanges .. It was also decided to suggest to CSM to substitute Hts (time at which precipitation given by nn began or ended, depth of snow) for jj in the code for those two reports each day that do not include maximum and minimum temperaturn. These- proposals are incorpoTuted in He solution 4 (CHM-I). 3.4 Analysis and publication of data on flood-producing storms (Agenda item 3.4) The commissIon studied the proposals submitted by the president of CHM, Canada, and the United States. It was agreed that guidance rna-texial for the analysis and publication of data on flood-producing storms should be Included in the Guide for Hydro-logical M.eteorology. The guidance IDateriill should cover: (a) The procedures for making supplement 3.5 Content of climatic atlase.s with resPect to w(Jter resource development (Agenda item 3.5) The commlsslon eXClmined the list of map!? contained in the annexes to Resolution 30 (EC-IX) and noted that many of the climatic maps needed by hydrologists are listed therein. The annex to necommendation 4 (CHM-I) contains a ti~it of climatic IT\aps which could usefully be added. In view of the importance of the role to be played by the regional associations in the preparation of regional climatic atlases, the commis~Jion considered that each association should have a working group to study inter alia climatic maps for hydrological purposes. It was also felt that the list given In Annex 3 to Resolution 30 (EC-IX) contained some maps which ought to be included in regional atia.ses ']nd this list should therefore be examined by the regional associations. The commission considered that it would be useful to have a representative serve on the CCI Working Group on Climatic Atlases. The above d~cisions Jre lncorporated in Recommendation 4 (CHM-I). 3.6 Avalanche warnings and forecasts (Agenda item 3.6) The commission noted the report submitted by the Secretary-General in accordance wi Hi the decision of Ee-XII. It also noted with appreciation the interesting document prepared for the session by Mr. M. R. de Quervain on existing methods of avalanche warnings and fore~ casts. It was the consensus of the commission that there was no need for WMO to assume re sponsibility for problems of avalanche warnings and forecasts at the present time. The com mission considered that the existing arrangements for exchange of information on avalanche research was adeq~ate and that collaboration between countries on information needed for ava lanche w~rnings and forecQsts could best be arranged on a bilateral basis. The commission agreeci, however, that seminars for training of personnel concerned with avalanche warnings would be very useful and suggestions to that effect are made under agenda item 5.3. Co operation with other interested organizations in organizing such seminars was considered advisable. 307 Study of seiches (Agenda item 307) The commission agreed that in addition to the' study of seiches on lakes and land locked seas, the study and predicti.on of water levels in estuaries is of concern to meteoro logists also, and that the Working Group on Hydrological Forecasting should pay attention to GENERAL SUMMARY 7 these subjects. The commission recommended that the Secretary-General conduct a survey of existing hydrological forecasting services to establish the status of current knowledge con cerning seiches; it adopted Recommendation 5 (cru.l-I) on this subject. 3.8 Standardization of terminologY. codes and units (Agenda item 3.8) The commission agreed that there was an urgent need for the standardization of termi nology used in hydrological meteorology and attention was given to efforts already made in this direction by WMO, UNESCO, IASH and other international bodies. TITe International Meteoro logical Vocabulary (Provisional Edition 1959) was examined and it was noted that a definition of "hYdrometeorologyU appeared on page 2 and that definitions of other terms of interest to the commission 'appeared under section 551.579. Neither the selection of terms nor the defi nitions given were considered satisfactory and it was therefore decided in Resolution 5 (CHM-I) to set up a working group to prepare a better list of terms and suitable definitions, taking into account the list of terms given in Annex I of the report. In the meantime, it was suggested in Recommendation 6 (CHM-I) that section 551.579 and the definition of "hydro meteorology" shoul-d. be omitted from the International Meteorological Vocabulary. In view of the work of UNESCO in the field of scientific terminology, it was decided that the working group should provide advice as required to UNESCO. The group was also requested -to consider the need for changing the content of section 551.579 of the Universal Decimal Classification~ On the question of codes-, the commission agreed that details of codes needed for use in the rapid exchange of information for hydrological forecasting in international river basins could best be left to regional associations and to individual countries. TITe commission noted that Resolution 30 (Cg-III) covered the standardization of units as regards the messages for the international exchange of data. The Working Group on Publi cation and Exchange of Data for Hydrological Meteorology (see Resolution 3 (CHM-I)) was asked to exrunine the que~tion of standardizing units for pUblication purposes and to bring forward any recommendations to the next session. 3 .. 9 Recommendations adopted at the Nairobi Joint Symposium on Tropical Met-eorology in Africa (Agenda item 3.9) 3.9.1 Radar observing systems (Agenda item 3.9.1) Under this item the commission discussed the recommendation on radar observing systems adopted by the Symposium on Tropical Meteorology in Africa held in Nairobi in December 1959, and Hecommendation VIII adopted by the first Inter-African Conference on Hydrology, Nairobi, January 1961~ The commission agreed that observations by radar systems should be fully devel oped for hydrological purposes. It was recommended that the Members of WJv10 should be urged to carry out investigations on the present use of radar observations for hydrological purposes .. The commiss-ion also recommended that an inquiry among Members on this subject should be car ried out. These decisions are incorporated in Recommendation 7 (CHM-I). The commission fur ther agreed that mai:erial on application of radar to hydrology should be included in the Guide to Hydrological Meteorology (see agenda item 5.2) and that the potentialities of radar observation of prec:lpi tation should be brought to the attention of the Working Group on Net- work Design.. . Influence of land use (Agenda item 3.9.2) The commissJ.on noted Recommendation 8, Influence of land use, adopted by the SymposiL!m on Tropical Meteorology, which was held in Nairobi in December 1959 under the joint auspices of WMO and the Muni ta1p Foundation. The commission agreed that investigations of the effect of forest and swamps and of changes in land use on the water balance and on river regime are of great importance for de velopment of the national economy of countries located not only in tropical but also in other climatic regio-ns 0 It was agreed that Wfl'lO should stimUlate studies of these problems. Further more, it was recommended that the Secretary-General should approach the various international organizations concerned, in particular FAO and UNESCO, with a view to co-ordinating the efforts 8 GENERAL SUMMARY of WMO in this field with those of other organizations concerned and, if appropriate, devel oping joint activities with these organizations. Recommendation 8 (CHM-I) was adopted on this subject. 3.10 Accuracy of measurements as required for hyd!o!ogical meteorology (Agenda item 3.10) The commission considered this item on the basis of the list of elements and accuracy requirements contained in Resolution 9 (CCl~III). It was felt that for the elements used in hydrological meteorology the accuracy stated by CCl would be adequate. For some applications a lower degree of accuracy would be acceptable, but as the future use of any given measurement cannot always be foreseen at the time it is made, the accuracy requested by eel should .be aimed at. The commission noted that there were several elements used in hydrological meteorology not listed by· eel and agreement was reached on the accuracy required for measurements of these elements. The decisions of the commission are contained in Resolution 6 (CHM-r). 3.11 Evaporation measurements "nd control (Agenda itom3.l1) The commission emphasized the. importance of the problem of evaporation measurements and control.- It agreed that inv.0stigations of different methods of measurement and control shOUld be continued. The commission decided to call the attention of ClMO to the need for guidance in protecting evaporation pans from, birds and other animals. It was further agreed that there was a need for continued studies of the relation be tween evaporation from pans and nearby lakes and that the Secretary-General should be re quested to collect i~formation on such studies from Members and to present a consolidated re port on this question to the next session of the. commission. The commission noted that lASH was also active in the field of evaporation measurements and control and that any future ac tivities of the commission in this field should be car:;ried out in close collaboration with that association. It was also agreeq that the item "Evaporation measurements and control'l should be taken up as a subject for a symposium, preferably to be arranged in collaboration with erMO and lASH. Finally, without making any specific proposals at the present time, the commission wished to stress the need for making available funds to undertake investigations on different aspects of evaporation measurements and. control. The commission invited the president of CHM to draw this matter to the attention of the Executive Committee, bearing in mind the possi bilities of obtaining support from other organizations such as UNESCO for this purpose. In this connexion attention waS also drawn to the WMO Operational and Technical Development Fund. 3.12 Meteorological factors in hydrological design (Agenda item 3.12) This item was discussed by the commission on the basis of a document submitted by Australia. The importance of making the best use of meteorological factors in hydrological design was generally recognized and in some countries this is probably the most f mpo.rtant as pect of the national activities 1n hydrological meteorology at this time. The commission felt that the action to be taken under this item was closely related to that und~r item 5.2 and the decisions of the session are accordingly recorded under item 5.2. 3.13 Or anizational structure of the h drometeorolo ical work in different countries Agenda item 3.13) The commission noted with great interest the information about national meteorological and hydrological services contained in document E/3070 of the Economic and Social Council of the United Nations. It was decided that it would be useful to have an addendum to this docu ment prepared before the next session of the comm~ssion and Recommendation 9 (CHM-I) was ac cordingly adopted to this effect. GENERAl. SUMMARY 3.14 Recommendations ado ted at the First ,Inter-African Conference on H drolo Agenda item 3.14 The commission examined a number of recomritendations adopted at the 'First Inter-African Conference on Hydrology, held in Nairobi, Kenya, from 12 to 26 January,l96l. The discussion was'based on a written report by the WMO observer at the conference, Mr. B. W. Thompson, and on information provided at the s.ssion by the representative of the CCrA, Mr. J. Rodier. The following coiuments on the recommendations were,agreed upon: Recommendation III - Standardization of rainqauges , ' It would be very difficult to ensure that all countries use the same pattern of rain_ gaug_and the commission felt that the purposes of this recommendation will largely be met by the act.ionbeing toikenunder Resolution 12 (EC-IX). At the same time, it was desirable that elMO should make recommendations designed to achieve uniform exposure of raingauge •• , ,Recommendation ry- Accuracy 1n spatial sampling of rainfall This subject will be dealt with by the Working Group on Network Desiqn (see Resolu~ tion 2 (CIIM~I)) and the Working Group on Hydrolo,gJ.,cal Forscastinl! {see ResolutIon 1 (CHM-I)). Recommendation v - Maintenance ~f networks of rainqauges This question is covered by Regulation 2.0.1.1 of the WMO Technical Regulations. Guidance material on the inspection of precipitation stations will also be included in the Guide to Hydrological Meteorology. Recommendation VI - Measurement of rainfall intensity The need for adequate networks of autographicraingauges will be discussed in the Guide to Hydrological Meteorology. ' Recommendation VII _ Rainfali intensity-duration-area-freguency relationships , The Guide to Hydrological Meteorology will include material on the study of this ques- tion. Recommendation VIII - Value of radar in studies of rainfall See the decisions taken 'under agenda item 3.9.1. Recommendation XLIV - Standardization and installation of .v"porimeters and evapotranspiro meters ,See the decisions taken under agenda item 3.11. Recommendation XLV- Measurements of and studies of evaporation and evapotranspiration Recommendation XIX - Need for caution 1n using experimental results from the temperate regions Re,commendation XXXII- Inter-African co-operation in the field of hydrology The implementation of these recommendations is an internal matter for cerA, and no action is required by the commission. They might be examined at the next session of Regional Association I with a view to determining if WMO can assist cerA in impiementing the recommen dations. The commission wished to place on record its view that there should be continued close collaboration' between WOO and cerA, and it wa. suggested that the Secretary-General should com municate the comments recorded 'above to CCrA and express appreciation for the assistance pro~ vided at the session by the cerA representative. 4. WORKING RELATIONS WITH REGIONAL ASSOCIATIONS, OTHER TECHNICAL COMMISSIONS AND OTHER INTERNATIONAL ORGANIZATIONS 4.1 Regional association activities in hydrological meteorology (Agenda item 4.1) The commission considered that the regional associations had a useful rille to play in hydrological meteorOlogy by assisting in the implementation at the regional level of the 10 GENERAL SUMMARY technical decisions arising from the work of CHM, this is in particular so because many practical problems in hydrological meteorology are of limited areal extent. The existence of four regional Working Groups on Hydrological Meteorology was noted with satisfaction and it was agreed that the commission should endeavour to stimulate further action in this field by the regional associations. A list of items which might usefully be studied by these asso ciations is contained in Recommendation 10 (CHM-I). The attention of the presidents of regional associations is drawn to the decisions of the commission under agenda item 5.7. 4.2 Commission for Instruments and Methods of Observation (Agenda item 4.2) 4.2.1 geii£a£ili1Y7oi ~ain1ainin~ £ Tse£a£a1e_c£m~iisiou io£ lnit£~euti ~n~ Me1h£di £f Qbie£v~tiou \Agenda item 4.2.1 The commission reviewed the actIon taken by other constituent bodies with regard to the desirability of maintaining a separate Commission for Instruments and Methods of Observa tion and decided to recommend that in view of the many instrumental problems still to be solved, CIM 4.2.2 Ex ansion of WMO Publication No. 8 TP. 3 to include h drolo ical meteorolo Agenda item 4.2.2 The commission noted with interest the proposed list of contents of Chapter 15 of the Guide to International Meteorological Instruments and Observing Practice prepared by the CIMO Working Group on Hydrometeorological Instruments. The commission agreed that all the elements proposed by the CIMO working group should be included. It was further recommended that the existing Chapter 7 on "Measurement of precipitation and evaporation" should be considerably expanded and should then be divided into three separate chapters on precipitation, evapora~ tion and snow. In the chapter on precipitation, guidance should be given on the Use of radar for estimating the amount of precipitation over an area. The president of CHM was requested to convey the above views to the president of ClMO. In view of the great interest of CHM in the methods of observation of the elements of the hydrologic cycle, it was felt that members of CHM should have an opportunity of commenting on any new material on these elements prior to its publication in the Guide and also of preparing new material. To meet these and similar needs, the president of CHM was requested to keep close contact on these matters with the president of CIMO and to inform the members of CHM of any development of importance to the commission. It was further decided to establish a Working Group on Instruments and·· Methods of Observation with the terms of refer" ence laid down in Resolution 7 (CHM'"I). 4.3 United Nations and specialized agencies (Agenda item 4.3) The commission reviewed the present arrangements whereby WMO is collaborating with the United Kations and with other specialized agencies in water resource development projects in accordance with the policy laid down in Resolution 19 (Cg-lII). The historical background to this work was described by the representatives of the United Nations ar~ the World Health Organization; the representative of the IUGG expressed regret that it had been found neces sary to divide the responsibilities for hydrology at the inter-governmental level between so many of the specialized agencies. The commission was of the opinion that the present status of the relations of WMO with the United Nations and with other specialized agencies sufficiently covered the intention of Resolution 19 (Cg-III) and that no specific action was necessary. GENERAL SUMMARY 11 4.4 International Association of Scientific Hydrology (ItKlG) (Agenda item 4.4) The commission noted with approval the existing collaboration between WMO and lASH itnd considered that this collaboration should continue in future On as close a basis as pos siblel this would be in accordance with Resolution 19 (eg-III); On research questions of common interest it Was reI t that lASH should have primary responsibility and that WMO should be represented on the relevant lASH committees. On practical questions of common interest which fall within the competence of CHM, and which involve discussions and action'at an inter governmental level, the commission felt that WMO should have the primary responsibility and that lASH should be invited to be represented on any relevant WMO working groups. It was further decided in principle that WMO and lASH could, with advantage, organize joint 'symposia, and the details of this possibility Were discussed under agenda item 5.3. Reference i. also made to the decision taken under agenda item 3.1 with regard to the Inter national Bibliography on,Hydrology. 5. GENERAL QUESTIONS 5.1 ' Drafting of technical regulations for hydrological meteorology (Agenda item 5.1) The eommission hated that in general the WMO Technical Regulations should not include any reference to standard or recommended practices and procedures which "have not' been 'suffi Ciently clearly established. Fo'r this reason, it was felt that it would ba premature to attempt to draft /lny technical regulations i11 hydr~lcigical meteorology during the present ses sion when the commission was still in the early developmental stages of its programme. It was beHeved that most of the technical procedures recommended by the commission should 'atpresent be in the nature of gUidance material. The WOrking Group on the Guide. on Hydrological'meteoro logy (see. Resolution ~ (CHM-I» was 'requested to consider whether any 0.£ the' items to be dealt with in the Guide ought to be included in the technical regulations and, if so, to sub mit drafts of these regulations to thEisecond session of the commission. 5.2 Preparation of internaHonal guide on hydrological meteorology (Agenda item 5.2) The commission considered that one of its most. important tasks was to prepare a guide On hydrological meteorology. A prOvisional list of corttents of the Guide is given in Annex II to this report. This list is intended {oprovide general directives to the Working Group on the Guide on Hydrological Meteorology established in Resolution 9 (CHM-l) and to the working groups charged with the drafting of individual chapters and sections- see Resolutions 7, 2, 3,.1, and 8 (OIM-I). The commission reallzed that modifications to the list of contents might become necessary as the work proceeded, and the president was authorized to approve such modi fications on behalf of the commission. It was decided that the Guide should be reasonably self-contained even if this meant reproducing materi~l already included in other WMOGuides. To facilitate the inclusion of amendments and 'additions to the Guide, the commission recommended that it shOUld be'published in loose-leaf form. The commission hoped that it would be possible to complete the Guide in time for con sideration at its. next session. For this reason the working groups charged with the prepara tion of IndIvidual sections and 'chapters were requested to complete this work by the end of 1963 and the president was requested to endeavour to arrange for a session of ·the Working aL'OUp on Hydrological Meteorology early iri 1964. It was agreed that the draft chapters should be circulated to members of the commission for comment as they become available. Under this item the commission' also discussed the need for work on hydrological design (see agenda item 3.12) and it was decided in Resolution 8 (CHM-I) that the Working Group on Hydrological Design should prepare a technical note on the general aspects of this question in addition to the section for the Guide on applications to water resource development. It was felt that further technical notes dealing with specific aspects of hydrological design would also be very valuable and the 'working group was requested to suggest subjects which might usefully be dealt with In these notes. 12 GENERAL SUMMARY 5.3 International seminars and symposia. (Agenda item 5.3) The commission noted that WMO had already organized several scientific symposia and training seminars of fnterest to hydrological meteorologYt and it was agreed that continued activities on these lines would help to further the aims of the commission. In this work, WMO should collaborate with other international organizations and especially with the lASH (see agenda item 4.1), the WMO programme of symposia in hydrological meteorology should be closely co-ordinated with the lASH programme. The commission recommended that WMO should organize symposia on the following sub- jects, listed in order of priority: Networks for hydrologIcal meteorology (see agenda item 3.2) Hydrological forecasting esee agenda item 3.1) Evaporation measurements and control (in collaboration with elMO: see agenda item 3.11) Quantitative prediction of precipitation The main reason for assigning the highest priority to the symposium on the design of networks for hydrological meteorology was that this was considered to be the most important subject from the point of view of the developing countries. It was thought to be of particu lar importance to bring hydrologists and meteorologists together. The result of the discus sion during this symposium could also be of great value to the Working Group on Network Design. The symposium on hydrological foreGasting should cover the following subjects: (a) Principles and theoretical factors: Antecedent condit10ns Relations of run-off to precipitation (b) Practical techniques: Correlation techniques Machine methods (c) Verification of hydrological forecasts (d) Design storms (e) Flood movement in rivers. It was hoped that it would be possible to organize one of these symposia jointly with the lASH during the week preceding the next General Assembly of the IU3G (Berkeley, 1963). The commission recommended that WMO training seminars should be organized on the following subjects, listed in order of priority: Hydrological forecasting (see agenda item 3.1) Avalanche forecasting (see agenda item 3.6) . At least one seminar should be held each year and should have a duration of approxi mately one month. Seminars on hydrological forecasting should deal mainly with river forecasting tech' niques and be held in various part of the world, each representative of different climatic conditions and operational problems. For example, separate seminars might relate to the fol lowing climatic regions: humid tropics, serni-ar-id and arid zones, temperate zone, sub-polar regions. The' commission noted that plans were being made for a. WMO symposium on tropical meteorology in 1962, and suggested that those responoible for selecting the topiCS to be discussed might consider the inclusion of one or more of the following: - Application of hydrOlogical meteorology to water resource development Measurement of evaporation. in arid regions Quantitative prediction of precipitation Instrumentation and exposure of instruments GENERAL SUMMAIW 13 5.4 Establishment of working groups (Agenda itein 5.4) The following working groups were establishe.d to carry out the programme of the commission between the first and second sessionl . Working Group on Hydrological Forecasting Working Group On Network Design working Group on Publication and Exchange of bata for Hydrological Meteorology Working Group on Terminology Working Group on Instruments and Methods of Observation Working Group on Guide on Hydroiogical Meteorology Working Group on Hydrological Design In each case the chairman of the working group was designated by the commission and as far as possible the individual members were also nominated. The commission realized the difficulties iriherent in the conduct of working group busines.s entirely by correspondence. If·was not at this time!n a DosiHon to identify exact priori Hes for sesslonsof all its working groups •. However, the oommissionwiShed to record lts desire that faciH ties be made available by the organization for at least two of its work iog groups to, meet prior to the second session of the commission. The president was requested to establish appropriate priorities for sessions depending upon the pr·ogress of the working groups arid to make arrangements with the Secretary-General as appropriate for the convening of sessions, taking into account the decision rl!cordecl in the lastparsgraph of Resolution 9 (CHM-r). . . 5.5 Election of officers (Agenda item 5.5) Mr; Max A. Kohler wasre-elected president, and Mr. L. J. Tison was elected vice president. 5·.6 Date and place of the second session (Agenda item 5.6) Since no invitations were presented at the session, the commission agreed that the date and place of its second session, whlch would normally take place in about four years' time, should be decided by the president aHerconsultatinn with the Secretary-General. 5.7 Clarification of the terms of reference of the commission (Agenda item 5;7) This item was placed on the agenda because opinions on the scope of the activities of the commission differed Widely, There was ·a group of delegates 'who took the view that questions related to river stage and flow, lake. level, lake and river ice, glaciers,sediment transportation, flow of springs, water temperature and waier quality, fell within the terms of reference of the commission. There was, on the ·other hand, a group of delegates which felt that such questiohswere beyond the scope of activity of the commission •. The commission agreed that the terms of reference laid down by Third Congress were not clear, but it d.ecided that it "Guld be unwise at this early stage to define all its long-term tasks too precisely. It was decided to concentrate its activities in the forthcoming period, until its next session, on problems of a meteorological nature, such as rainfall and evaporation (evapo transpiration) •. andon related hydrological problems of surface water and the water balance, in particular in connexion with short-term and long-term hydrological forecasting •. It was agreed that for the time being .studies of glaciers, sediment transportQtion. flow of springs and water quality should be excluded. . In so decIding, the commission was aware of the responsibilities which WMO had accep ted in the technical assistance programmes of the United Nations on water resources develop ment, and also of the fact that many countries needed advice on the setting up of networks for the measurement of those meteorological and hydrological elements wnlch are closely inter related. 14 GENERAL SUMMARY The Principal Delegate of the United .Arab Republic wished to· have recorded his objec tion to the de_cision of the commission under agenda i tern 5.7 ... 5.8 Action to be taken on decisions of the session The commission decided that the resolutions 'and recommendations adopted at the session should all be submitted direct to the Executive Committee for consideration at its thirteenth session, May 1961. The other main decisions of the commission recorded in the reports of the working committees and -in the minutes of plenary sessions have been reported in the preceding para graphs of this general summary. Where necessary, action on these decisions will be taken either directly by the president of the commission or by the Secretary-General, acting on his behalf. 5.9 Participation in meetings of the American Geophysical Union and the American Meteol'o", logical Society The American Geophysical Union held its 42nd annual meeting in Washington, D.C., from 18-21 April 1961. Participants at CHM-I were given an opportunity to attend some of the lec tures given in the hydrology and meteorology sections. The scientific_meetings in meteorology were held jointly between the American Geophysical Union and the American Meteorological Society. . 5.10 Exhibits An exhibit describing activities of U. S. agencies in the field of water resources was on display during the entire session of the commission. ·Also, selected instruments used in the collection of basic hydrological and meteorological data in the United States were dis played during a limited period of the meeting. The exhibit waS organized by and under the -direction of the Department of Commerce~ Weather Bureau, with the following agencies partici pating: Department of Agriculture Agricultural Research Service Forest Service Soil Conservation Service Depa~tment of the Army Corps of Engineers Department of Commerce Bureau of Public Roads Coast and Geodetic Survey Weather Bureau Department of Health, Education and Welfare Public Health Service Department of the Interior Bureau of Reclamation Geological Survey 5.11 Field trip A field trip was arranged for the participants during the week-end 15-16 April 1961. rhe tour included a visit of various installations of hydrological interest in the area of Harrisburg, Pennsylvania; such as Gettysburg, Weather Bureau Airport-Station in Harrisburg, U. S. Geological Survey Digital Gauge, Radio River Gauge on the Susquehanna, and Hydro Plant at Safe Harbour& GENERAL SUMMARY 15 Most of the delegates took part in the trip which waS a great succeSS. 5.12 Closure of the session Eight plenary meetings were held during the session. The minutes'of the first four plenaries were approved during the session and the president was authorized to approve the remaining minutes on behalf of the commission. He was also authorized to-make any necessary minor editorial changes to the text adopted during the session. In closing the session, the president expressed warm appreciation to all who had con tributed to the sUccess of the session, and in particular to the chairmen of the working com mittees, Mr. Bleeker and Mr. Clements. This was heartily endorsed by a number of delegates. The president also expressed the appreciation of the commission to Mr. K. Langlo, represen tative of the Secretary-General, and to Mr. O. M. Ashford and Mr. P. I. Miljukov of the WMO Secretariat for their enthusiastic and untiring assistance to the work of the session. The representative of the Secretary-General paid special tribute to the excellent services pro vided by the host country, and similar remarks were made by other speakers. 16 RESOLUTIONS ADOPTED BY THE SESSION Res. 1 (CHM.r) - WORKING GROUP ON HYDROLOGICAL FORECASTING THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING, The terms of reference of CHM; which include inter a11a" • ~ the study and formu lation of meteorological requirements for hydrology!!; CONSIDERING, (1) ·That the development of hydrological forecasting has great significance for various usersJ (2) That hydrological forecasting is still in a state of development, (3) That a thorough study of this subject is necessarYI DECIDES, (1) To establish a Working Group on Hydrological Forecasting with the following terms of reference, (a) To study and formulate the meteorological services needed for purposes of short and long-term hydrological forecasting; (b) To prepare a report in a form suitable for pUblication as a technical note on the following lines: (i) outlines of generally accepted procedures for hydrological forecasting, (ii) summaries of types of meteorological information required for short- and long-term hydrological forecasting, and (iIi) lists of basic references of common interest in hydrological forecasting, (c) To prepare recommendations on the development, improvement, and promotion of meteorological services to meet the needs of hydrological forecasting; (d) To prepare a chapter on hydrological forecasting for inclusion in the Guide to Hydrological Meteorology! (2) To invite the following individuals to serve on the working group: Eugeni G. Popov (chairman) D. N. Body W. Eschweiler Tor Nordenson An expert to be designated by lASH (3) To request the working group to submit the draft chapter of the Guide before the end of 1963 and its final report with recommendations to the president of CHM not later than six months before the next session of the commission. RESOLUTIONS 2, 3. 17 Res. 2 (CHM-I) - WORKING. GROUP ON NETWORK DESIGN THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING WMO Technical Notes Nos. 25 and 26, CONSIDERING, . (1) That although the need for continued investigation of network design is well established, practical guidance material could now be prepared, (2) That such material would assist in defining adequate and reasonable minimum networks, (3) That the issuance of such material by WMO would tend to promote improved net works where existing facilities are inadequate, DECIDES, (1) To set up a Working Group on Design of Network for Hydrological Meteorology with the following terms of reference, (a) To prepare guidance material on network design and on the evaluation of the ade quacy of existing networks, (b) To collect information on existing networks, necessary for the fulfilment of the above task, .. (c) To assume responsibility for drafting the chapter on network design for the Guide on Hydrological MeteorologYQ (2) To invite the following individuals to serve on the working group: J. Rodier (chairman) !kutin Jacobs Walter B. Langbein Valeryan Andreevlch Uryvaev An expert to be designated by the Netherlands An expert to be designated by lASH (3) To request the working group to submit the draft chapter of the Guide before the end of 1963 and its final report to the president of CHM not later than six months before the next session o_f the commission .. Res. 3 (CHM-I) - WORKING GROUP ON PUBLICATION AND EXCHANGE OF DATA FOR HYDROLOGICAL METEOROLOGY THE COMMISSION FOR HYDROLOGICAl. METEOROLOGY, CONSIDERING, (1) That a large ~~ount of potentially useful meteorological data is not pub lished and may not be readily available to hydrologists, (2) The desirability to determine which meteorological data in published form are required by hydrologistsl . 18 RESOLUTIONS 3, 4 (3) The need for guidance mate~ial on collection, processing and publication of data for hydrological meteorologYI DECIDES, (1) To establish a Working Group on Publication and Exchange of Data for Hydro·· logical Meteorology with the following terms of reference: (a) To study meteorological data for the purpose of determining which data in pub lished form are of interest to hydrologists I (b) To examine to what extent such data are included in meteorological publications, such as yearbooks, monthly bulletins, etc., (c) To prepare a chapter on "Collection, processing and publication of data" for inclusion in the Guide to Hydrological MeteorologYI (2) To invite the following individuals to serve on the working group' James P. Bruce (chairman) V. Figuera Z. Kajetanowicz An expert to be designated by the United Kingdom An expert to be designated'by lASH (3) To request. the workinq group to submit the draft chapter for the Guide before the end of 1963 and its final report of their findings, with recommendations, to the president of CHM not later than six months before the next.session of the commission. Res. 4 (CHM-I) - TRANSMISSION OF PRECIPITATION DATA THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING that Regional Association IV and some countries in other regions have arranged for transmission of precipitation data at six-hourly intervals from all synop tic land stations I CONSIDERING, .(1 ) That the exchange of six-hourly precipitation data for other parts of the world would be extremely useful for various hydrological purposesl (2) That other information for hydrological purposes could be included in synop tic reports which do not contain maximum and minimum temperature I DECIDES, To request the president of CHM to invite the Commission for Synoptic Meteorology to investigate the practicability of introducing, on a regional basis, (a) Exchanges of precipitation data, at six-hourly intervals, from synoptic land stations I (b) Substitution of Rts (time at which precipitation given by RR began or ended, depth of snow) for jj in the code for those two reports each day that do not include maximum and minim~m temperature~ RESOLUTIONS 5,6 19 Res. 5(CHM-I) - WORKING GROUP ON TERMINOLOGY. THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, . NOTING Recommendation 6 (CHM-I); and CONSIDERING that UNESCO has an overall responsibility in questions relating to scientifictermi no logy I DECIDES, (1) To set up a. Working Group on Terminology with the following terms of reference: (a) To prepare a revised section 551.579 for the International Meteorological Voca bulary; . (b) To consider whether any changes are desirable in the content of section 551.579 of the Universal Decimal Classificationl (2) To invite the following individuals to serve on the working group: Wilhelm Friedrich (chairman) Armando Michelangeli L. J. Tison An expert to be designated by the Union of Soviet Socialist Republics An expert to be designated by the United Kingdom An expert to be designated by lASH (3) - To request the working group to submit the following reports to the pre~i dent of the commission: (a) A list of the terms commonly used in hydrological meteorology. together with definitions and the equivalent terms in the four official languages of WMO, by 1 July 1962; (b) A complete revised section 551.579 of the International Meteorological Vocabulary by 31 December 1962; (c) Suggestions regarding the content of section 551.579 of the Universal Decimal Classification by 31 December 1962; (4) To invite the Secretary-General to consult the working group as required on any questions relating to terminology ion hydrological meteorOlogy which may arise from UNESCO, and AUTHORIZES the president of the commission to approve reports (a) and (b) on .behalf of the commission and to forward them to the Secretary-General for appropriate action .. Res. 6(CHM-I) - ACCURACY OF MEASUREMENTS AS REQUIRED FOR HYDROLCGICAL METEOROLOGY THE COMMISSION FOR HYDROLOGICAL METEOROLCGY, NOTING. (1) Paragraph 5.8.1.7 of the Abridged Report of Cg.III; 20 RESOLUTION 6 (2) Resolution 9 (CCI-III), and CONSIDERIN3, (1) That the accuracy required in measurements for hydrological meteorology varies according to the purpose for which the measurements will be used, (2) That it is not always possible to know in advance for what purpose any particular measurement will be used; DECIDES, (1) That the accuracies specified in the annex to Resolution 9 (CC1-III) for the elements used in hydrological meteorology should be aimed at, (2) That the accuracy of measurement of certain additional elements should be as set out in the annex to the present resolution, (3) That the above statement regarding accuracy requirements should have the status of gUidance material onlYI and REQUESTS the president of CHM to convey the contents of this resolution to the president of elMO for inclusion in the Guide to International Meteorological Instrument and Observing Practice. ANN E X ACClffiACY OF MEASUREMENTS AS REQUIRED FOR HYDROLOGICAL METEOROLOGY (Additional to the annex to Resolution 9 (CC1-III)) Element Desired accuracy Water temperature Nearest O~ 1 DC Depth of snovI Nearest 1 em Specific gravity of snow Nearest 0.01 water equivalent of snow As for precipitation Soil moisture 1 per cent of oven-dry weight River and lake level Nearest 3 nun stream discharge Nearest 2 per cent NOTES (a) For some purposes in hydrological meteorology a lower degree of accuracy would be adequate, but as measurements may be used for purposes not foreseen at the time they are made, the accuracies laid down ahove and in the annex to Resolution 9 (eCl-III) should be aimed at. (b) For studies of freezing of lakes and rivers, a higher accuracy of water tempe rature measurement may. be needed when the water temperature is near to freezing point. RESOLUTIONS 7.8 21 Res. 7(CHM~I) ~ \'laRKIN:> GROUP ON INS1RUMENTS, AND METIlODS OF OBSERVATION THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, CONSIDERIN:>, (1) The great importance for its worle on having adequate guidance material on intruments and methods of observation used in hydrological meteorology; (2)' The material which has already been published in the Guide to International Meteorological Instruments and Observing Practices and the plans of CIMO for improving this publication; DECIDES, (1) . To establish a Working Group on Instruments and Methods of Observation with the following terms of reference: (a) To review the Guide to International Meteorological Instruments and Observing Practices from the point of view of hydrological meteorology; (b) To consider the instruments and methods of observation required to meet the needs of hydrological meteorology and to draft -amendments and additional material for the Guide to International Meteorological Instruments and Observing Practices with a view to insuring that these needs are adequately met; (c) To assume responsibility for drafting the chapter on Instruments and Observing Practices for inclusion in the Guide on Hydrological Meteorology. (2) To invite the following individuals to serve on the working group: Rolland W. Carter (chairman) Jose M. Raffo del Campo A. K. Proskuryakov An expert to be designated by the United Kingdom An expert to be designated by lASH An expert to be designated by CIMO (3) To request the working group: (a) To submit its report to the president of CHM by 31 December 1963; (b) To report at an earlier date on any matters on which more urgent action is considered to be desirable. Res. 8(CHM~I) - WORKING GROUP ON HYDROLOGICAL DESIGN THE COMMISSION FOR HYDROLCGICAL METEOROLOGY, CONSIDERIN:>. (1) The importance of the application of hydrological meteorology to the design of hydraulic structuresi (2) The need for improving and developing the methods used in this type of application; 22 RESOLUTION 9 DECIDES, (1) To establish a Working Group on Hydrological Design with the following terms of reference: (a) To prepare a general report on the application of hydrological meteorology to the design of hydraulic structures - in a form suitable for publication as a WMO technical notel (b) To make suggestions on specific aspects of hydrological design which might be dealt with in more detail in separate WMO technical notes, (c) To draft the section O~ applications to water resource development for the Guide on Hydrological Meteoro]ogYJ (2) To invite the followjng individuals to serve on the working group: A. F. Rainbird (chairman) Robert H. Clark Julian Lambor G. Remenieras An expert to be designated by India An expert to be designated by lASH (3) To request the working group to submit the following reports to the pre sident of the commission: (a) The general report by 1 July 1963, (b) The section for the Guide on Hydrological Meteorology by 31 December 1963, (c) A final report six months before the next session of the commission. Res. 9 (CHM-I) - WORKI~~ GROUP ON GUIDE ON HYDROLOGICAL METEOROLOGY THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING Resolution 18 (Cg-II); and CONSIDERING the urgent need for the preparation of a Guide on Hydrological MeteorologYI DECIDES, (1) To establish a Working Group on the Guide on Hydrological Meteorology with the following terms of reference: . (a) To draft the section of the Guide dealing with methods of analysis, (b) With the assistance of the Secretariat, to co-ordinate and integrate into the draft Guide the material provided by the working groups charged with the res ponsibility for preparation of different parts of the Guidel (2) To invite the following individuals to serve on the working group: Max A. Kohler (chairman) James Po Bruce Rolland W. Carter Eugeni G. Popov A. F. Rainbird J. Rodier RESOLUTION 9 23 (3) To request the working gro.up to submit the draft of the Guide to the pre sident of the commission at least six months before the next session of the commissionl and REQUESTS the president of the commission to inform the Executive Committee of the importance attached by the commission to holding a session of the working group early in 1964, RECOMMENDA TIONS ADOPTED BY lHE SESSION Rec. l(CHM-I) - BIBLIOGRAPHY ON HYDROLOGICAL FORECASTING , lHE COMMISSION FOR HYDROLOGICAL METEOROLOGY j NOTING, (1) 'The existence of an international bibliography on hydrology, distributed by the International Association of Scientific Hydrology of IUGGI (2) That this bibliographY,does not contain all literature appearing 1n the field of hydrological meteorologYI and CONSIDERING the need for identifying in the' above bibliography all papers re ferring to hydroiogical forecastingl RECOMMENDS, (1) That Members of WMO who have not 'submitted national bibliographtes on sub jects relating to hydrological meteorology to the International ASSOCiation of Scien- tific Hydrology be urged to do so in the future I . (2) That the Secretary'-General of WMO be directed tocontacf the Secretary General of lASH to arrange for the identification of hydrological forecasting publi cations in the International Bibliography on Hydrology. Rec. 2(CHM-I) - TRANSLATION OF VALUABLE PUBLICATIONS ON HYDROLOGICAL FORECASTING THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, CONSIDERING the need for making Inore generally availaP1. to research workers the knowledge obtained by some countries in the field of hydrological forecastingl RECOMMENDS that the Secretalll-General be requested I (1) To select, in conSUltation with the president of the commission, Bome of the most important publications on hydl:ological forecasting, for which there is • sub stantial demand, for translation and publication in one of the official languages of the Organizationl (2) To endeavour to obtain funds from thE> Expanded Programme of Technical Assistance or other SOurces for this purpose. Ree. 3(CHM-I) - RAPID EXCHANGE OF INFORMATION REQUIRED FOR HYDROLOGICAL FORECASTING ON INTERNATIONAL RIVERS lHE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING, (1) Resolution 19 (Cg-III)I RECOMMENDATION 4 25 (2) The bilateral and multilateral arrangements which have been made for rapid exchange of hydrological information on an operational basis on river basins extending across the borders of several countries; CONSIDERI!K;, (1) The desirability for WMO to collaborate closely with existing international bodies. such as the Danube Commission, responsible for such arrangements, (2) The need for making available to interested Members information about exist ing arrangements for rapid exchange of data required for hydrological forecasting on international rivers3 RECOMMENDS that the Secretary-General be requested: (a) To establish close collaboration with international bodies, such as the Danube Commission, responsible for rapid exchange of hydrological information on inter national rivers; (b) To collect information on existing systems such as codes, times and frequency of observation for exchange of data required for short-term hydrological forecasting on international rivers) (c) To distribute this information,to Members and presidents of regional associations, in an appropriate forml (d) To present a report on this question to the next session of the commission. Rec. 4(CHM-I) - CLIMATIC MAPS FOR HYDROLOGICAL PURPOSES THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING, (1) Resolution 30 (EC-IX) I (2) Resolution 6 (CCl-III), and CONSIDERING that the list of maps given in Annex 3 to Resolution 30 (Ee-IX) is very useful but incomplete; RECOMMENDS, (1) That the maps listed in the annex to the present recommendation be added to Annex 3 to Resolution 30 (EC-IX), (2) That the complete list be studied by regional associations with a view to determining which of the maps ought to be included in regional climatic atlases I and CONSIDERING FURTHER that machinery for co-o,'dinating this work is provided by the Working G:roup Gh Climatic Atlases of the Commission for Climatology; RECOMIAENDS that arrangements be made for the Commission for Hydrological ~eteo l'ology to be represented on the Working Group on Climatic Atlases of the Commission for Climatology. 26 RECOMMENDATION 5 ANN E X SPECIAL ClIMATIC MAPS FOR HYDROLOGISTS PRECIPITATION 1. Mean annual precipitation for 30-year period (if definite seasonal variations exist, then maps should be provided showing this variation). Monthly distribution for selected stations by bar chart on annual map should be included. 2. Variability of annual rainfall from year to year. 3. Maps showing details of depth-duration-frequency for point precipitation and a means for extending these data to provide data on areal precipitation (duration 5 minutes to 72 hours, frequency 2 years to 50 years). 4. Maps of frequency and duration of droughts. 5. There may be need for maps sho~ing maximum snow accumulation and. water equivalent. HUMIDITY Mean monthly vapour-pressure or dew point (not relative humidity). EVAPORA nON 1. . Mean annual evaporation from free water surface. 2. Variability of annual evaporation from year to year. 3. Mean annual actual evapotranspiration (precipitation minus run-off). TEMPERA IURE Mean monthly water surface temperature. NOTE: The above list is not exhaustive. In some countries there are undoubtedly needs for additional climatic maps for hydrological purposes. Rec. 5 (CHM-I) - STUDY OF SEICHES THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, CONSIDERIU3, (1) That studies and forecasts of seiches on lakes and land-locked seas involve meteorological considerations I and (2) That it would be useful for many Members if information on this subject were made aval.lable; RECOMMENDS, (1) That Members be requested to submit to the Secretary-General information on studies and existing methods of forecasting selchesl RECOMMENDATIONS 6,7.8 27 (2) That the Secretary-General be directed to prepare a report summarizing the information submitted and to make this report avallable to Members. Rec. 6 (CHM-I) - INTERNATIONAL METEOROLOGICAl VOCAEULARY THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, HAVING EXAMINED the International Meteorological Vocabulary (Provisional Edition 1959), and . CONSIDERING, (1) That this publication does not meet the need' for standardizing the toL'mino logy used in hydrological meteorology in that neither the terms inclUded under sectlon 551.579 nor the deflnitions of these terms are satisfactorYI (2) That it would be impossible to prepare a satisfactory revised version of this section of the Vocabulary in time for inclusion in the next editionl RECOMMENDS that section 551.579 and the definition of the term "hydrometeorology" appearing in the Vocabulary be omitted from the International Meteorological Vocabulary for the time being. Rec. 7(CHM-I) - RADAR OBSERVATIONS OF PRECIPITATION THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING, . (1) Recon~endation 8 (STM) .on Radar Observing Systems adopted by Symposium on Tropical Meteorology in Nairobi, December, 1959; (2) Recommendation VIII - Value of radar in studies of rainfall - adopted by the First Inter-African Conference on Hydrology, January 19&1; CONSIDERING the need for further .investigatIon on the us. of radar observations of precipitatIon for purposes of hydrological forecasting; RECOMMENDS, (1) That Members be,urged to carry out investigations on the use of and pot en tiaU ties of radar observaHons of precipitation for the purpOSes of hydrological fore casting; (2) That the Secretary-General be directed to collect information from Members on applIcation of radar to hydrology and to make the result of the inquiry available to Me.nbers before the second session of the Commission for Hydrological Meteorology. Rec. 8 (CHM-I) - INFLUENCE OF I.AND USE THE COMMISSION FOR HYD,ROLOGICAL METEOROLOGY NOTING Recommendation 11 (STIA) - Influence of land use, adopted by the Symposium on Tropical Meteorology in Africa, December, 19591 28 RECOMMENDATIONS 9,10 CONSIDERING that the problem of, influence of land use on river regime and On water balance has great importance for development of the national economy of countriss located not only in tropical but also in other climatic regions, RECOMMENDS, (1) That Members be encoUraged to undertake and continue meteorological and hydrological investigations on: (a) The effect of forest and swamps On river regime and water balancel (b) The effect of changes in land use on river' regime and water balance, both for small and large catchments I (2) That the Secretary-General be requested to approach various international organizations concerned, in particular FAO and UNESCO. with a view to co-ordinating the effort of WMO in this field with those of other organizations concerned and, if appropriate, developing joint activities with these organizations. Rec. 9 (CHM-X) - ORGANIZATION OF 'METEOROLOGICAL AND HYDROLOGICAL SERVICES THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, NOTING ECOSOC document NO. E/30701 and CONSIDERING, (1" That this document contains much useful information for Members. (2) That developments with regard to the organization at the national level of meteorological and hydrological services have taken place in some countries and that many countries have become independent states since the document was prepared, RECOMMENDS, (1) That the Secretary-Genera1 be requested to 'propo~e at the next' Inter-Agency Meeting on Water Resource Development that arrangements be made for preparing an ad dendum to document No. E/3070, with special attention to countries not included in the original document; , (2) That copies of the addendum be distributed to Members well in advance of the second session of the commission. Rec.10(CHM-I) - REGIONAL ASSOCIATION ACTIVITIES IN HYDROLOGICAL METEOROLOGY THE COMMISSION FOR HYDROLOGICAL METEOROLOGY, CONSIDERING that the regional associations can assist in the implementation at the regional level of the programme of the World Meteorological Organization in hydro logical meteorology I and NOTING with satisfaction that four of the regional associations have already established working groups in hydrological met eoro logy I RECOMMENDATION 10 29 RECOMMENDS, (1) That regional associations be encouraged to pursue and intensify their ac tivities in hydrological meteorologYI (2) That special attention be given by the regional associations to the follow ing problems: (a) The promotion of the establishment of regional networks of stations for hydro- logical meteorological purposesl (b) The preparation of climatic maps for hydrological purposesl (c) The operational exchange of data for hydrological meteorological purposesl (d) The application on a regional basis of meteorology.to hydrological problems such as flood forecasting and computation of water balance, especially on international river basinsl (e) The topics which might be dealt with at seminars on hydrological meteorology and the preliminary studies which may be required in this connexlon. 30 ANNEX I Annex to paragraph 3.8 of General Summary SIl0Rt LIst OF HYDROLOGIC TERMS English French affluent affluent airline correction correction d'obliquite (partie aerienne du cruble de suspension) alluvium alluvion annual flood crUe annue 11 e . aquifer aquifere erea-depth'-curve ·courbe surface-hauteur area-discharge curve courbe surface debit artesian artesien backwater remou.s bank berge barrage barrage base flow dehl. t de bas. basin bassin bed load charriage de fond brook l'uisseau by-pas. canal de derivation canal canal catchment area bassin versant channel chenal chute chute citmatic year anne. climatique concentration time temps de concentration Cone of depression cBne de depression critical depth profondeur critique current courant current meter moulinet hydrometrique cut-off coupure dam barrage, digue degradation creusement delta delta depth gauge echelle limnimetrique design flood crUe servant aU calcul ANNEX I 31 design storm averse servant au calcul dike digue discharge debit ditch fosse drought secheresse duration curve courbe de debit classe echo-sounder sondeur par echo eddy tourbillon embankment berge energy gradient gradient d'energie erosion erosion estuary estuaire evaporation evaporation evapotranspiration evapotranspiration flood erue flood forecasting prevision des erues flood frequency frequencs des crues flood routing propagation des erues flow ecoulement flume canal (de mesure) freshet courant dfeau douce gauging station poste de jaugeage ground water eall souterraine head charge (hauteur) head waters hautes eaux hook gauge pointe limnimetr1.que hydraulic hydraulique hydrograph hydrogramme hydrologic cycle cycle hydrologique hydrology hydrologie hydrometeorology hydrometeorologie inclined gauge echelle inclinee infiltration infiltration inflow ecoulernent affluent interception interception isohyet isohyete lag time temps de reponse levee digue limnology limnologie 32 ANN E X ! lysimeter lysimetre mass -CUrve courbe cumule" meander me andre nappe nappe outflow effluent . percolation percolation perma.frost permafrost permeabUi ty permeabiHte . pler jetee, digue Pitot tube tUbe de Pitot plateau plateau pluviograph pluviom~tre enregistreur pOlder polder pond Hang pool mal'e porosity porosite potamology potamologie precipitation precipitations raingauge pluviometre rapids raplC:1es reservoir reservoir retardation retard river cours d'eau roughness coefficient coefficient de rugosite run-off ecoulement saturation saturation scour affouillement sedimentation sedimentation seepage :tnfU tration seiche seiche sUt silt (sable tres fin) snow gauge nivometre soil sol soU moisture humidlte du sol sounding sondage spillway deversoir spring source staff gauge echelle de crue stage niveau ANN E X I 33 st"age-discharge curve courbe de tarage storage emmagasinement storm averse stream cours d 'eau stream gauging jaugeage des cours dfeau . suspended load materiaux en suspension swamp marecage thalweg thalweg thaw degel Thiessen polygon polygone de Thiessen transpiration transpiration tributary tributaire, affluent time of travel temps de propagation unit hydrograph hydrogramme unitaire valley vallee valley storage stockage de vallee velocity of flow vitesse du courant water demand demande d t eau water-level recorder limnigraphe (limnimetre anregistreur) watershed bassin versant waterway cours d'.au (naturel ou artificiel) wave onde weir deversoir well puits 34 ANNEX II Annex to paragraph 5.2 of General Summary OUTI.INEOF GUIDE ON HYDROLOGICAL METEOROLOGY A. Introduction Scope and purpose of the Guide. B. Instruments· -and Observing Practices 1. Elements~to be.observed. (CHM-I/Doc. 42,giving the commission interpretation of the terms of reference, should be followed in selecting the elements.) 2. Instruments (radar measurements of precipitation should be included). 3. Methods of observation and related calculations. ("Related calculations'" are ihtend~d to include, for example, such matters as calculation of discharge from stage observations, and adJusting recording rain gauge data to agree with standard gauge observations.) 4. Siting of stations. Note: Elements 'should be treated separately and subsections 2-4 dealt with under each element. C. Network design 1. General principles. (This subsection should include guidance on the need for co-ordinated planning of precipitation, stream flow and evaporation networks.) 2. Density levels of networks. (Requirements for various degrees of accuracy - see action on agenda item 3.2.) Note: This main section should deal with network requirements for both basic data collection and operational forecasting. D. Collection, processing and publication of data 1. Collection. (a) Reporting procedures (report forms, frequency, etc.), (b) Quality cantrall (c) Storage and ,cataloguing (including use of punched cards and tape). 2. Processing. (a) Routine analyses (for example, plotting of monthly isohyetal maps, of hydrographs, means, standard deviations); (b) Preparation of maps of water balance elements (requirements, maps of pre cipitation, evaporation, run-off, etc.). ANNEX It 35 3. Publication - bulletins, yearbooks, etc. (Requirement, format, frequency, units - see pUblication and exchange of data - agenda item 3.3.) Note: This main section should be concerned with both planning and design, and with operational requirements. E. Methods of analysis This main section should include the empirical, statistical, and physical ana lyses required for such applications as are considered in sections F and G. It should include guidance on analyses of flood producing storms (agenda item 3.4), unit hydrograph derivation, rainfall-intensity-duration frequency studies and other matter suggested in CHM-I/Doc. 13, Appendix A, and CHM-I/Doc. 21. F. Hydrological forecasting 1. Objectives and general concepts (the value to various users should be included). 2. Classification of types of forecasts and warnings (annual', seasonal, short term, ice forecasting, etc.)_ 3. Forecasting methods. (Among the sub-headings should be included such questions as rainfall-run-off correlations, snowmelt-run-off computations, ice forecasting, unit hydrograph applications, flood routing, confidence limits of forecasts.) 4. Verification and evaluation of forecasts. (In addition to methods of verification of individual forecasts, this subsection should include an appraisal of the relative merits of various forecasting methods under different conditions.) 5. Hydrological forecasting services: (a) Organization; (b) Dissemination of forecasts and warnings. 0.... Applications to water resource development The purpose of this main section is to provide guidance on the uses of the ana lysis' methods outlined in section E in appraising the water resource potential of • region and in carrying out basic hydrological studies required in the design of projects for the development and control of water resources~ SOIDe examples of such application are spillway design flood determinations for reservoir design, and rain fall intensity frequency studies for small watershed and urban drainage design. 36 LIST OF DOCUMENTS Doc. No. Title. Agenda item Submi tted by 1 Revised provisional agenda 1.3 Rev. I, Add. 1 2 Explanatory memorandum to the provisional agenda Add. 1. 2. and 3 3 D~sirability of maintaining a Secretary~en.ra1 separate commission for Instruments and Methods of Observation 4 Hydrological forecasts Secretary-General 5 ·International Association of Secretary-General Scientific Hydrology 6 Regional association activities Secretary-General in hydrological meteorology 7 Content of climatic atlases with 3.5 Se.cretary-General respect to water resource development 8 Influence of land use sacretary-General 9 Radar observing systems Secretary-General 10 Accuracy of measurements as 3·10 Secretary;....Genera,l required for hydrological meteorology 11 Expansion of WMO Publication No.8. Secretary-General TP. 3 to include hydrological meteorology (CIMO Working Group on Hydrometeorological Instruments) Add. 1 12 Drafting of technical regulations S.ecretary-General for hydrological meteorology 13 PreparatIon of International Guide Se-cratary-General on Hydrological Meteorology 14 International seminars and symposia 5.3 Secretary'-General 15 Report by the president of the 2 President, CHM Commission for Hydrological Meteorology. Add. 1 LIST OF DOCUMENTS 37 Doc. No. Titl~ Agenda item Submitted by 16 Standardizati.on of terminology President, CHM codM and units 17 United Nations and other Secretary-General specialized agencies 18 Hydrological fOrecasts Switzerland 19 Hydrometeorologica1 networks Swi tzerland 20 Publication and exchange of data 3.3 Switzerland 21 Meteorological factors in Australia hydrological design 22 Publication and exchange of data Secretary-General 23 Avalanche warnings and forecasts Secretary~General Add. 1 and 2 24 Hydrometeorologic.al networks President, CHM 25 Analysis and publication of data President, CHM on flood-producing storms Carr. 1, Add. 1 26 Study of seiches President, c!U~ 27 Organi"ational structure of Federal Republic hydromete.orologicaJ. work in of Germany different countries 28 Hydrometeorological networks Secretary~G~neral 29 Avalanche warnings and forecasts Secretary-General 30 Recommendations adopted at the Secretary-General First Inter-.African Conference on Hydrology 31· Hydrological forecasts Canada 32 Analysis and publication of data Canada on f:'.ood-producing storms 33 Analysis and pUblication of data 3.4 United States on fh10d-producing stonos 34 Surface water survey United Kingdom 35 Publication and exchange of data Israel broadcast of precipitation amounts 38 LIST OF IXlCUMENTS Doc. Title Agenda item Submitted by No. 36 The significance of stream gauging, 301 Regional Office rUn-off dot.a. and hydrological and of the Ame:dcas forecasts to the planning, design 3.2 fOr WHO and operaHon of sanitary works 37 Ev~poration measurements and control India 38 Hydrological forecasts Chairman, Committee A 39 Desirability of maintaining a Chairman, Committee B separate Commission for Instruments and Methods of Observation 40 Expansion of IVMO Publication No.8. Chairman; Committee B TP.3 to include hydrological meteorology . 41 Meteorological factors in 3.12 Chairman, Committee B hydrological design 42 Report of sub-committee to plenary 43 Regional association activities in Chairman. Committee B hydrologi.cul meteorology 44 United Nations and other Chairmant Committee B specialized agencies 45 International Association of Chairman. Committee B Scientific Hydrology 46 Publication and exchange of data Chairman, Committee A Rev. 1 47 Analysis and publication of data Chairman, Committee A on flood-producing storms 48 Avalanche- warnings and forecasts Chairman. Committee A 49 study of seiches Chairman, Committee A 50 Accura.cy. of measurements· as required Chairman. Committee B for hydrological meteorology 51 Organizational Structure of the Chairman. Committee B hydrometeorologicol work In different countries 52 Drafting of technical regulations Chairman, Committee B for hydrological meteorology 53 Evaporation measurements and control Chairman, Committee A LIST OF DOCUMENTS 39 Doc. Agenda item Submitted by No. Title 54 Radar observing systems Chairman, Committee A 55 Report by the president of the 2 Chairman, Committee A commlssion 56 Influence of land use Chairman, Committee A 57 Hydrometeorological networks Chairman, Committee A 58 Content of climatic atlases with. Chairman, Committee B respect to water resOurce development 59 Standardization of terminology, codes 3.8 Chairman, Committee B and units 60 Recommendations adopted at the 3.14 Chairman, Committee B First Inter-African Conference on Hydrology 61 Report of committee on membership 54 Chairman of Committee of working groups 62 Election of ofUcers - Report of Chairman the Nominations Committee 63 Preparation of International Guide Chairman, Committee B On Hydrological Meteorology International seminars and symposia Chairman, Committee B