Vodna bilancaSlovenije 1971–2000

Water Balanceof Slovenia 1971–2000

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^e kje na Zemlji obstaja ~arobnost, se skriva v vodi.

If there is magic on the planet, it is contained in the water.

Loren Eisley

naslovnica.qxd 18.3.2008 14:30 Page 1

Vodna bilancaSlovenije 1971–2000

Water Balance of Slovenia 1971–2000

Ljubljana 2008

^e kje na Zemlji obstaja ~arobnost, se skriva v vodi.

If there is magic on the planet, it is contained in the water.

Loren Eisley

VODNA BILANCA SLOVENIJE 1971–2000 / WATER BALANCE OF SLOVENIA 1971–2000

Vodna bilanca Slovenije 1971–2000 Water balance of Slovenia 1971–2000

© Ministrstvo za okolje in prostor – Agencija Republike Slovenije za okolje© Ministry for Environment and Spatial Planning – Environmental Agency of the Republic of Slovenia

Urednik / EditorPeter Frantar

Uredni{ki odbor / Editorial Boardmag. Marjan Bat, Peter Frantar, mag. Zlatko Mikuli~, mag. Jo`e Uhan, mag. Florjana Ulaga

Avtorji besedil / Text Authorsmag. Marjan Bat, Mojca Dolinar, Peter Frantar, Mauro Hrvatin, dr. Mira Kobold,Bla` Kurnik, Mateja Nadbath, Vesna O`ura, mag. Jo`e Uhan, mag. Florjana Ulaga

Kartografija / CartographyMojca Dolinar, Peter Frantar, mag. Jerneja Fridl

Kartografska podlaga / BasemapGeografski in{titut Antona Melika ZRC SAZUAnton Melik Geographical Institute SRC SASA

Lektoriranje / ProofreadingMiriam Stanonik / Prevajalska agencija Alkemist – Alkemist Translation Agency

Prevod / TranslationPrevajalska agencija Alkemist / Alkemist Translation Agency

Tehni~na urednika / Technical editorsPeter Frantar, mag. Florjana Ulaga

Drugi sodelavci / Other contributorsMartin Baj`elj, Renato Bertalani~, Ur{a Gale, Jure Jerov{ek, mag. Tadeja Ovsenik-Jegli~,Mojca Robi~, Vlado Savi}, Mojca Su{nik

Fotografije so prispevali / Photographies were contributed byPeter Frantar, Anja Jerin, Albert Kolar, Bla` Ko{ak, Toma` Kra{nja, Matej Lipar, Alenka Mihori~,Mojca No~-Razinger, Matej Ogrin, Milan Robi~, Iztok Sinjur, Florjana Ulaga

Fotografiji na zunanjih straneh / Cover photographiesZgornji Peri~nik / The Upper Peri~nik Waterfall – Peter FrantarKapljice jutranje rose / Morning Dew Dops – Albert Kolar – Sokol

Izdajatelj / PublisherMinistrstvo za okolje in prostor – Agencija Republike Slovenije za okoljeMinistry for Environment and Spatial Planning – Environmental Agency of the Republic of SloveniaVojkova 1b, p. p. 2608, 1001 Ljubljana, e-po{ta: stik@arso.gov.si

Oblikovanje in tisk / Design and PrintSYNCOMP d. o. o.

Naklada / Edition2000 izvodov

Internet:www.arso.gov.si

Ljubljana, marec 2008

CIP – Katalo`ni zapis o publikacijiNarodna in univerzitetna knji`nica, Ljubljana

556.532(497.4)"1971/2000"

VODNA bilanca Slovenije 1971–2000 = Water balance of Slovenia1971–2000 / [avtorji besedil Marjan Bat … [et al.] ; urednikPeter Frantar ; kartografija Mojca Dolinar, Peter Frantar, JernejaFridl ; prevod Prevajalska agencija Alkemist ; fotografije soprispevali Peter Frantar … et al.]. – Ljubljana : Ministrstvo zaokolje in prostor, Agencija Republike Slovenije za okolje, 2008

ISBN 978-961-6024-38-91. Vzp. stv. nasl. 2. Bat, Marjan 3. Frantar, Peter, 1975–237729536

AGENCIJA RS ZA OKOLJE

3

VsebinaContents

1 Uvod / Introduction (J. Uhan) ...................................................................................................................................................................................................................... 7

2 Vodna bilanca / Water Balance (M. Bat, P. Frantar) .................................................................................................................................................................... 9

3 Vplivni dejavniki na vodno bilanco / Water Balance Impact Factors (P. Frantar, M. Nadbath, F. Ulaga) ...................................... 15

3.1 Lega in relief / Location and Relief ...................................................................................................................................................................................... 15

3.2 Podnebje / The Climate ................................................................................................................................................................................................................ 18

3.3 Kamnine in prsti / Rocks and Soils ...................................................................................................................................................................................... 21

3.4 Rastlinstvo / Vegetation .................................................................................................................................................................................................................. 24

3.5 Antropogeni dejavniki / Anthropogenic Factors ........................................................................................................................................................ 26

4 ^leni vodne bilance / Water Balance Elements ...................................................................................................................................................................... 29

4.1 Padavine / Precipitation (M. Dolinar) .................................................................................................................................................................................... 294.1.1 Geografska razporeditev padavin / The Geographic Distribution of Precipitation .................................................... 334.1.2 ^asovna porazdelitev padavin / The Temporal Distribution of Precipitation .................................................................. 34

4.2 Izhlapevanje / Evaporation (P. Frantar, B. Kurnik, V. O`ura) .................................................................................................................................. 394.2.1 Geografska razporeditev izhlapevanja / The Geographical Distribution of Evaporation .................................... 41

4.3 Pretoki / Discharges .......................................................................................................................................................................................................................... 434.3.1 Preto~ni re`imi / Discharge Regimes (P. Frantar, M. Hrvatin) ............................................................................................................ 434.3.2 Trendi pretokov / Discharge Trends (P. Frantar, M. Kobold, F. Ulaga) ............................................................................................ 504.3.3 Specifi~ni odtoki 1971–2000 / Specific Runoff in the 1971–2000 Period (P. Frantar) .............................................. 604.3.4 Odto~ni koli~niki / Runoff Coefficients (P. Frantar) .................................................................................................................................. 66

5 Vodna bilanca obdobja 1971–2000 / The Water Balance for the 1971–2000 Period (P. Frantar) ................................................ 71

5.1 Pregled vodne bilance po pore~jih / Overview of the Water Balance by River Basins .......................................................... 745.1.1 Pomurje / Pomurje (The Mura River Basin) .............................................................................................................................................. 745.1.2 Podravje / Podravje (The Drava River Basin) ............................................................................................................................................ 755.1.3 Posavje / Posavje (The Sava River Basin) ...................................................................................................................................................... 755.1.4 Pokolpje / Pokolpje (The Kolpa River Basin) .............................................................................................................................................. 765.1.5 Poso~je / Poso~je (The So~a River Basin) ........................................................................................................................................................ 775.1.6 Povodje jadranskih rek brez Poso~ja / The Catchment Area of the Adriatic Rivers Without Poso~je ............ 785.1.7 Slovenija / Slovenia .......................................................................................................................................................................................................... 79

6 Sklep / Conclusion (M. Bat, P. Frantar) ................................................................................................................................................................................................ 81

7 Literatura / Literature .................................................................................................................................................................................................................................. 85

Priloge / Appendix ................................................................................................................................................................................................................................................ 89

Zadostne koli~ine voda in njihova dobra kako-vost sta klju~ni za vsakodnevno ̀ ivljenje ljudi inve~ino gospodarskih dejavnosti. Sta pomemb-na dejavnika kakovosti ̀ ivljenja in trajnostnegarazvoja.

Krovna direktiva o vodah zavezuje dr`avek doseganju okoljskih ciljev na podro~ju voda,poplavna direktiva in aktivnosti v zvezi z su{amipa so dopolnitev obstoje~ih instrumentov vodnepolitike z vidika koli~inskega stanja voda. Na~rtiupravljanja vodnih obmo~ij se dopolnjujejo z ana-lizami in re{itvami, ki bi omogo~ili vzpostavitevravnote`ja med razpolo`ljivostjo in rabo vodnihkoli~in na posameznem vodnem obmo~ju.Za na-~rtovanje trajnostnega upravljanja z vodnimi virije potrebno upo{tevati posebnosti posameznih,npr. kra{kih obmo~ij.

Pomanjkanje vode in su{e postajajo velik pro-blem, podnebne spremembe pa stanje {e poslab-{ujejo. Razmere vplivajo na naravne vire v oblikinegativnih u~inkov na biotsko raznovrstnost, ka-kovost voda, tveganja za gozdne po`are in {irje-nje su{nih predelov.V tak{nih okoli{~inah postajaprednostna naloga priprava u~inkovitih strategijza bla`enje posledic su{ in pomanjkanja vode terupravljanja tveganj s su{ami. Prvi korak pri spo-padanju z navedeno problematiko je trajnostnoupravljanje z vodnimi viri.To pomeni predvsemvar~nej{o in u~inkovitej{o rabo voda v vsakda-njem ̀ ivljenju, kot tudi v vseh od vode odvisnihgospodarskih dejavnostih.

Slovenija se uvr{~a med dr`ave, ki so z vidi-ka vodnatosti, sorazmerno bogate.V zadnjih tri-desetih letih pa je zelo o~itno upadanje re~negaodtoka. Ker ima ve~ina na{ih rek hudourni{kizna~aj, pretoki zelo hitro narastejo in tudi hitroupadejo. Intenzivne lokalne padavine povzro-~ijo lokalne poplave hudourni{kega zna~aja, kiprizadenejo manj{a pore~ja ali dele pore~ij.Vo-dotoki s hudourni{kim zna~ajem pa so {e pose-bej ranljivi v ~asu malih pretokov in hidrolo{kesu{e.

Obstoje~a vodna politika, katere klju~ni izzi-vi so zagotavljanje dobrega stanja voda, zahte-va uveljavitev u~inkovite cene vode po na~elu»porabnik pla~a«, opozarja na pomen ustrezne-

Sufficient quantities of good quality water areof key importance to people's everyday life andfor the majority of economic activities.They areimportant factors of both quality of life and sus-tainable development.

The Water Framework Directive binds coun-tries to achieving environmental objectives inthe area of water, while the Flood Directive andthe activities concerning droughts supplementthe existing instruments of the water policy inthe area of the quantitative status of water.Theplans for managing water areas are supplement-ed by analyses and solutions that will allow a bal-ance to be maintained between the availabilityand utilisation of water quantities per individ-ual water area. In order to plan the sustainablemanagement of water resources, it is necessaryto observe the characteristics of the individualareas, e. g. karstic areas.

Droughts and the lack of water are becom-ing a serious problem, and climate change is onlyaggravating the situation.These conditions affectnatural resources, having negative effects on bio-diversity, the quality of the water, the risk of for-est fires and the expansion of drought-prone areas.In these circumstances, the preparation of effec-tive strategies for mitigating the consequencesof droughts and the lack of water, as well as themanagement of drought risks, are becominga priority task.The first step in tackling this issueis the sustainable management of water resources.This primarily means the more economical andefficient use of water in everyday life as well asin all the branches of economy that depend onwater.

Slovenia ranks among the countries that arerelatively rich in terms of water abundance.Thedecline in river runoff is quite clearly visible overthe last thirty years.The majority of our rivers havea torrential character, with discharges increas-ing and decreasing very rapidly. Intensive localprecipitation causes local floods of a torrentialnature, affecting smaller river basins or parts ofriver basins.Watercourses with a torrential natureare especially vulnerable during the period of lowdischarges and hydrological drought.

4

VODNA BILANCA SLOVENIJE 1971–2000 / WATER BALANCE OF SLOVENIA 1971–2000

PredgovorForeword

ga prostorskega na~rtovanja in na gospodarnostrabe vode. Prisotna je skrb za vklju~evanje vodneproblematike v na~rtovanje drugih gospodarskihdejavnosti. Politi~ne odlo~itve pa morajo temelji-ti na visoki kakovosti znanj in informacij o zna-~ilnostih vodnega kroga in trendov.

Priprava vodne bilance Slovenije je predvi-dena v Nacionalnem programu varstva okolja.Zdru`uje podatke rednega spremljanja vseh dejav-nikov vodnega kroga, od padavin, izhlapevanja,zalog in odtoka. Z njeno pomo~jo lahko pridobi-mo prvo oceno o stanju vodnega okolja po posa-meznih povodjih in predstavljajo eno od podlagza ukrepanje. Zato nas veseli, da je pred namipublikacija, ki nam bo to omogo~ala.

dr. Mitja Briceljdr`avni sekretarMinistrstvo za okolje in prostor

The existing water policy, the challenges ofwhich are assuring the good ecological status ofwaters, requires the establishment of an effec-tive price for water according to the »user pays«principle, warning of the importance of suitablespatial planning and the economical use of water.It includes provisions for including the water pol-icy in the planning of other economic activities.Political decisions must be based on high qual-ity knowledge and information on the charac-teristics and trends of the water cycle.

The preparation of the Slovenian water bal-ance is envisaged as part of the National Envi-ronmental Protection Programme. It combinesthe data from regular monitoring of all the watercycle elements, ranging from precipitation, evap-oration and reserves through to the runoff.Thiswill help us obtain the first estimate of the sta-tus of the water environment in the individualcatchment areas and will represent one of thebases for taking measures. Therefore we aredelighted that we now have a publication thatwill enable us to do all this.

Mitja Bricelj, PhDState SecretaryMinistry of the Environment and Spatial Planning

5

PREDGOVOR / FOREWORD

Slika 1: Ob Tolminki / Figure 1: By the Tolminka River

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Voda je eden najpomembnej{ih `ivljenjskihnaravnih virov. Podatki o njenih koli~inah pred-stavljajo pomembno izhodi{~e na~rtovanja razvojadru`be in so podlaga globalni viziji prostorske-ga razvoja.Voda v prihodnje ne bo samoumevnorazko{je, zagotavljanje vode razli~nim uporab-nikom bo {e te`avnej{e.V vodni krog vse pogo-steje in vse mo~neje posega ~lovek z rabo in ure-janjem voda in prostora. Poznavanje prostorskein ~asovne razporeditve in ocene razpolo`ljivihkoli~in vode so klju~ne podlage upravljanju voda.Racionalnej{a raba in urejanje voda za zmanj{e-vanje posledic hidrolo{kih su{ in {kodljivega delo-vanja voda je pomemben cilj nacionalnega progra-ma upravljanja z vodami.Doseganje zastavljenegacilja je mo~no povezano z ugotovitvami obdobnenacionalne vodne bilance oz. zna~ilnostmi pro-storske in ~asovne razporeditve vode.

Vodna bilanca je ra~unska shema vhodnih inizhodnih koli~in vode v poenostavljenem modeluvodnega kroga,ki ga je za analizo vodnih virov za-snoval geograf C.W.Thornthwaite (1899–1963)in s tem postal pionir izra~unavanja vodnebilance. Uporabnost rezultatov vodne bilancetemelji na razpolo`ljivosti in zanesljivosti podat-kov iz dolgoro~nih programov meritev, opazo-vanj in analiz procesov v hidrosferi.V rezultatihnacionalne vodne bilance se zrcali tudi stabil-nost delovanja nacionalne hidrolo{ke in meteo-rolo{ke slu`be, ki izvajata dolgoro~ne programemeritev in analiz.

Za dr`avno na~rtovanje upravljanja voda jepomemben obdobni vodnobilan~ni izra~un, kilahko nakazuje regionalne spremembe v pro-storski in ~asovni razporeditvi vode. Svetovnameteorolo{ka organizacija priporo~a tridesetletnobilan~no analiti~no obdobje. Pri~ujo~a {tudijapredstavlja rezultate vodne bilance od leta 1971do leta 2000 ter ugotavlja razlike glede na pred-hodno obdobje 1961–1990.

V {tudiji vodne bilance Slovenije za obdob-je 1971–2000 so uvodoma predstavljeni meto-dolo{ki pristop, podatkovni nabor ter nekateri

Water is one of the most important natural reso-urces that supports life. Data on its quantity rep-resents an important starting point for planningthe development of society and is the founda-tion for the global vision of spatial development.In the future, water will no longer be a luxurythat we can take for granted and the provisionof water to various users will be even more dif-ficult. Man is increasingly and substantially en-croaching on the water cycle by utilising andarranging water bodies and space. Knowing thespatial and temporal distribution and the esti-mates of the water quantities available is the keyfoundation for managing the water resources.The rational use and organization of water inorder to alleviate the consequences of hydrolo-gical droughts and harmful effects of the waterare an important objective of the National WaterManagement Programme.Achieving this objec-tive is strongly linked to the findings of the multi-annual national water balance and the charac-teristics of the spatial and temporal distributionof water.

The water balance is a calculation schemebased on the input and output quantities of waterin a simplified model of the water cycle createdby geographer C.W.Thornthwaite (1899–1963)for analysis of water resources, making him a pio-neer in the calculation of the water balance.Theapplicability of the water balance results is basedon the availability and reliability of data fromlong-term programmes of measurement, obser-vation and analysis of the processes occurringin the hydrosphere.The national water balanceresults also reflect the stability of the operationof the national hydrological and meteorologicalservices that conduct these long-term meas-urement and analysis programmes.

The multi-annual water balance calculation,which can indicate regional changes in the spa-tial and temporal distribution of water, is impor-tant for the national planning of water mana-gement.The World Meteorological Organization

7

1 UVOD / INTRODUCTION

1UvodIntroduction

Jo`e Uhan

Slika 2: So~a

Figure 2: The So~aRiver

8

VODNA BILANCA SLOVENIJE 1971–2000 / WATER BALANCE OF SLOVENIA 1971–2000

najpomembnej{i vplivni dejavniki na posamez-ne elemente vodnega kroga. V jedru {tudije sopodani in pojasnjeni rezultati bilan~ne analizeter glavne zna~ilnosti posameznih elementovvodnega kroga od padavin in izhlapevanja doodtoka.

Vodna bilanca Slovenije za obdobje 1971–2000prina{a pomembne ugotovitve o spremembahpadavinskega re`ima, ko jesenski vi{ek padavinpostaja bolj izrazit, medtem ko se v ostalih mese-cih koli~ina padavin zmanj{uje. Spremembeugotavljamo tudi pri izhlapevanju, ki se je v pri-merjavi s predhodnim vodnobilan~nim obdob-jem pove~alo. Posledice so spremenjeni preto~nire`imi med katerimi se zmanj{ujejo regionalnerazlike.Trendi pretokov so v splo{nem v upada-nju. Primerjava elementov vodne bilance obdob-ja 1971–2000 z obdobjem 1961–1990 nakazujepove~anje izhlapevanja in zmanj{anje odtoka.Ugotovljene spremembe na regionalni ravni krat-koro~no {e niso povzro~ile pomanjkanja vode,lokalno pa se zaradi njih tveganje pri zagotavlja-nju vode pove~uje.Po podatkih Evropske okoljskeagencije ugotovljene vodnobilan~ne spremem-be uvr{~amo v velikostni red pri~akovanih spre-memb povpre~ne letne razpolo`ljivosti vode naobmo~ju Slovenije do leta 2030.

Vodna bilanca Slovenije 1971–2000 ponovnoprina{a pomembno sporo~ilo o potrebni podpo-ri razvoju nacionalne hidrolo{ke in meteorolo{keslu`be. Hkrati je zadostno opozorilo za nujneukrepe v nacionalni politiki upravljanja voda inprostorskega planiranja, katerim je vodnobilan~-na {tudija najprej namenjena.

recommends a thirty-year analytical period forthe water balance. The present study presentsthe water balance results from 1971 to 2000 andestablishes the differences with respect to theprevious period of 1961–1990.

The study of the water balance in Slovenia forthe 1971–2000 period first presents the method-ological approach, the data set and some of themost important and influential factors affectingthe individual elements of the water cycle.Thecore of the study provides and explains the resultsof the water balance analysis and the main char-acteristics of the individual water cycle elements,from precipitation and evaporation to runoff.

The water balance of Slovenia for the 1971–2000 period is providing important findings onchanges to the precipitation regime, with theautumn peak becoming increasingly pronouncedand the amount of precipitation in the othermonths is decreasing.We are also finding changesin evaporation, which has increased in com-parison with the previous water balance peri-od.The results are changing discharge regimes,during which the regional differences are dimin-ishing.The discharge trends are generally declin-ing.The comparison of the elements of the waterbalance in the 1971–2000 period with that inthe 1961–1990 period indicate an increase inevaporation and a reduction in the runoff. In theshort-term, the established changes on a region-al level have not yet caused water shortages,though locally these changes are increasing therisks to the provision of water.According to thedata of the European Environmental Agency, theestablished water balance changes are classifiedinto the size order of the expected changes inthe average annual availability of water in theterritory of Slovenia by the year 2030.

The water balance of Slovenia in the 1971–2000period is again delivering an important messageon the necessary support for the developmentof the national hydrological and meteorologicalservice. It is also a sufficient warning to requireurgent measures in the national policy of watermanagement and spatial planning, for which thewater balance study is primarily intended.

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