KEYNOTES INTERNATIONAL SYMPOSIUM polders of theworl d Lelystad - The Netherlands - 1982 BIBLIOTHEEK DE HAAFF Droevendaalsesteeg3 a | 6708P BWageninge n r^^^rr^ \y\li(\ 'tv--' -•• ^.üURBBHEER POSTBüe a^ji 6800 HB ARNHEM-NEDERLAND 0623 6760 CONTENTS INTRODUCTION TOPOLDER S OFTH EWORL D 7 - W.A. Segeren. LANDAN DWATE RMANAGEMEN T 15 - E. Schultz. Fromnatura l toreclaime d land.Lan dan d watermanagemen t inth epolder s of theNetherland s 17 - K. Praniah. Land andwate rmanagemen t inpolder s 43 CONSTRUCTIONASPECT S 55 - P.C. Mazure. Thedevelopmen t of theDutc hpolde r dikes 57 - R. Segevs. Fromwindmil l towind-generator .Developmen t inpolde r construction 75 - M.A. Meyer. Construction aspectso fpolder s inth e world 91 AGRICULTURALASPECT S 119 - J.V.d. Veen. Agricultural aspects inpolde r areasi n theNetherland s 121 - H. Bvammer. Agriculture and food production inpolde r areas '37 SOCIO-ECONOMICAN D PHYSICALPLANNIN GASPECT S '63 - A.K. Constandse. From spontaneous settlement to integrated planning and development '65 - J.H.M. Kienhuis. Themanagemen t ofpolder s inth e Netherlands 175 - A. Sfeiv-Younis. Economic aspects of soil conservation programs inLDC' s 187 EiftLiOi i.•'.-.;' RIJKSINSTITUUT VOORNATUUFtBB-*F£* 2 - 3POSTBÜS9201 6800H 3 ARNHEM-NEDERLAND ENVIRONMENTAL ASPECTS 221 - J. de Jong and A.J. Wiggers.Poldersan dthei r environment inth eNetherland s 223 - M. Vannuaai. Ecological valueso fpotentia l polder areas 245 SPECIAL KEYNOTES 255 - A. Volker. Lessons fromth ehistor yo f impolderingi nth eworl d 257 - B. Verhoeven. Polderso fth efutur e 275 -4 INTRODUCTION TOPOLDER S OFTH EWORL D W.A. Segeren. 5- INTRODUCTION TOPOLDER SO FTH EWORL D Prof.ir.W.A .Segere n Professor inPolde r Development,Delf tUniversit y of Technology,Departmen to fCivi lEngineering ; Deputy-Director ofth eGovernmen t Service forLan d andWate r Use. Owingt ohe r situationHollan dha sacquire d alo to fexperienc ewit h polders throughoutth ecenturies .Th eare awher e theDutc h arelivin g hasbee nadapte db ythemselve s toth edemand smad eb ya populou san d prosperous country,suc h assafety ,spac e tolive ,t owor k andfo r recreation, facilities forth eproductio n of food andth epreservatio n ofnature .Th eexperience ,gaine db yth eDutc h inthi s fieldrejoice s ina larg e international interest.Thi sexperienc e isuse d indifferen t ways inman yothe rcountries .Considerin g thepossibilitie s andth e necessity toemplo y theDutc hexperienc ewit hdesign ,constructio n andmanagemen to fpolder selsewher e inth eworld ,i ti si n factself - evidenttha tth eintentio n toorganis e aninternationa l Symposiuman d Exhibition aboutpolder s inth eworl ddevelope d inth eNetherlands . 1982seeme d especially suitablebecaus e several interesting eventsan d anniversaries takeplac e inthi syear .Mos to fthe mar ealread y well-knownan dhav ebee ncommemorate d witha lo to fpublicit ybu t inthi sconnectio n somewil lye tb ementioned . OnMa y 28,fift yyear sago ,th eAfsluitdij k wasclose d and thisyea r interesting eventsar etakin gplac ewit hregar d toth eOosterschelde - damb yplacin g the6 6columns . Especiallywit hrespec tt oth eIJsselmeerpolder s the fortieth anni­ versaryo fth eNoordoostpolde r andth etwenty-fift h anniversaryo f Oostelijk Flevoland canb ementioned . Moreover,twenty-fiv eyear sag oth eInternationa l Institute for Hydraulic andEnvironmenta lEngineerin g has started international educationo nwate r control.Thi scours eha sbee nattende d byman y engineers fromal love r theworl d andgive splent yo fattentio n toth e lay-outan dmanagemen to f low-lying,fla tpolder-lan d withregar d to watermanagement. FinallyTN Oexist s fiftyyear si n 1982.Thi sorganisatio no npractica l andapplie d researchha salway sha dplent yo f interest inth eman y aspectso f livingan dworkin gi npolder-lan d inth eNetherlands . Aims Threeaim sar ebein gpursue dwit h theSymposiu m andExhibition : 1.Th eexchang eo fknowledg e andexperienc eo npolder so n international level,t opolicy-maker s andengineers ,scientists ,managers ,builder s andpolitician salike .Fo r thispurpos e circularswit ha "Callfo r papers"wer esen tal love r theworld .Th erespon swa soverwhelming ; after selectionb ya scientifi c committee,som e 150paper swit h subjects alli nth e fieldo fpolders ,hav ebee nprinted . Manypaper shav ebee nreceive do ncertai npolder-area s;a tth e sametim e therewa sa larg e interesti npaper so n landan dwate rmanagement .Man y papershav eals obee nreceive d forth eothe r themesb ywhic h itha st o benote dtha tth econtribution s on socio-economic aspects andphysica l planningan denvironmenta l aspects aremainl y ofDutc horigi ni n contrastwit h theothe r contributions fromal love rth eworld . Theexchang e ofknowledg e andexperienc ewil lhav e totak eplac e especially during the Symposium. Some 400participant s from6 0countrie shav eapplie d forth e Symposium. The fulfilmento fthi sai mwill ,a tan yrate ,no tdepen do nth enumbe r ofparticipant s andth ecountrie spresent . 2.T ooffe r thepossibilit y toth eDutc h tradean d industry tosho whe r knowledge toth eassemble dpolder-expert so fth eworl dbot hdurin g theSymposium ,b ymean so fth epaper s alreadymentioned ,an da tth e Exhibition,b ymean so fstand sshowin g informationo nthei rtrade . About 40firms ,institute s and serviceswil lus e thispossibility .A sa framework forth eactivitie so fth eExhibition-participant s the organisationha smad ea separat eexpositio n showingth evariou s aspects ofplannin gan d constructing apolde r indifferen t countries,eac hwit h theirow npeople' s nature,prosperity-level ,natur eo fth e soil,climat e and such-like.Thi sexpositio n isals odivide d inth eSymposiu m themes.I tha sbee nbuil t insuc h awa y thati tca nb euse d inwhol e or inpar ta sa framework fora nexpositio n abroadwher eDutc htrad e and industrywis h topresen t themselves.I nthi swa yth eai m- t o advertise theDutc h tradean d industryabroa d -ca nb e continued after theSymposium . 3.T osho wth eDutc hpeopl e inwhic hwa yothe r countrieshav ebee n dealingwit h the samecircumstances ,hopin gt ogai nmor e understanding forth ewa yw e livei nou row ncountry .Tha ti swh yman yactivities , interesting forth eDutc hpublic ,ar eorganise d allroun dth e Symposium andExhibition .Th eMinistr y ofTranspor tan dPubli cWork s hasissue da brochur e entitled "Polderso fth eWorld". 'I nthi s brochureman ydata ,collecte db y theSymposiu m organisation,hav ebee n reproduced easily accessible.Man yDutc han d foreign technical journals,paper san dothe rmedi apa y attention toth eSymposium . Spontaneously exhibitionso fpainting san dceramics ,it ssubject s inspiredb ypolders ,wil lb ehel d inLelysta d from4 til l 10October . Andmoreover ,a fe wday sth eexhibitio nwil lb eopene d forth epublic . TheExhibitio n aswel la sth eSymposiu mwil lb ehel di n the"Agora " inLelystad .Lelysta d actsalread y asa centr e forth eIJsselmeer - poldersan dwil lbecom e thecapita lo fth ene wpolder-province . Themeanin go fpolder s toth eworl d Thedescriptio n ofth emeanin go fpolder s toth eworl dha s tob e preceded firstb ya definitio no fwha ti smean tb y"polders" . Inparticula rprof.ir .A .Volke r givessom ethought s tothi si nth e serieso farticle s followinghereafter .Th e starting-point isth e followingdefinition : "Apolde r isa leve lare awhic hha soriginall y been subject,permanentl y orseasonally ,t oa hig hwate r level (groundwater or surfacewater )an d isseparate d fromth esurroundin ghydrologica lregime ,t ob eabl et o controlth ewate r levelsi nth epolde r (groundwater and surfacewater ) independently of thesurroundin g regime" . Theseparatio n fromth e surroundinghydrologica l regime andth e water levelcontro l inth eare aar eth emos timportan t characteristics ofa polder .The yar enecessar y tob eabl et ous eth eare a ina wa y thatwa sno tpossibl e inth eorigina lcondition .Othe r important characteristics ofa polde r areth e flatsurfac e andth e facttha t almostneve rbig ,fo ragricultur e troublesome stones,ar e found inth e soil.Th ereaso n forthi sca nb e found inth eorigi no fa polder , thedepositio no fparticle s eroded elsewhere,b yrunnin go r stagnant water.Th eabove-mentione d definition andexplanatio n ofa polde rma y leadt oman ydifferen tinterpretations . For instance inthi swa ya paddy-fiel d isa polde r justa sth e flood- plaino fa larg erive rprotecte d from floodsb y anupstrea m damwit h areservoir . Ingenera lneithe ro fthes earea sar e indicatedwit h thewor dpolder . Anyway,i nth eframewor k of "Polderso fth eWorld " apractica l approach hasbee n chosen forth edelimitatio no fth esubject . For theSymposiu m thosearea sar etake na ssubjec twher e development necessitates the samepractice san dtechnique s asth eone suse di n polders.Leve ltopograph y andhig horigina lwate r levelsar e characteristics ofthat . Inth e framework of theSymposiu m researchha sbee ndon eafte r areas where "polder know-how"i sessentia l for,especiall y agricultural, development.Th e International SoilMuseu m hasderived , fromth e FAO-UNESCOWorl d SoilMap ,th e fact that 1200millio nhectare s aret o be found in theworl d asa nabsolut emaximu mo f levelarea so fwhic h the soili sbein g influenced by groundwater or shows,b y itsprofile , regular flooding. These soilshav emainl y developed fromalluvia ldeposits .O f thisamoun t thepar twithou t growing season, 109millio nhectares ,ca nb e excluded atonce .Fro mth eremainin g 1100millio nhectare smor e thanhal f ist o be found inarea swhere ,a sfa ra sth e lengtho fth egrowin g season isconcerned , threecrop spe ryea r arepossible .Thes ear eth e tropical and subtropical regions.I tha sbee nassume d that enoughwate r for -1 0- forplan tgrowt h isavailabl e inth e formo frainfal ,soi lmoistur eo r irrigation.