Ante Blaće, anblace@unizd.hr Branimir Vukosav, bvukosav@unizd.hr

Robert Lončarić, rloncar@unizd.hrDepartment of Geography

University of Zadar14th European seminar on geography of water

Cagliari, 26 June – 7 July 2011

Croatia:

Central European and Mediterranean country Area: 56.538 sq km Territorial Sea: 31.479 sq km Population: 4.49 million (2009 estimated) Capital: Zagreb (population 800.000) Independent: since 1991

Croatian archipelago:

• 1246 islands and islets• 3,259 sq km (5.8% of Croatian territory)• Population: 121,606 (2001 census; • 2.74% of the total Croatian population)• Only 79 islands > 1 sq km• 47 inhabited islands

Traditional islands’ economy: vine and olive growing, fishery

Rapidly increasing population in the late 19th and early 20th century

Onset of mass emigration due to the crisis of the traditional economy → depopulation of the islands; process still present

Inadequate water supply systems – main obstacle for islands’ economical development

Natural featuresGeology Dinaric karst on Adriatic Carbonate Platform (AdCP) Karst procesess during numerous emersions Last emersion – LGM (-135 m) Mesosoic and Paleogene limestones and dolomites Eocene flysch and marl Quaternary sediments (Pleistocene loess)

Importance of less permeable sediments for surface hydrography

Mediterranean climatic influence

(Köppen’s classification)

Csa climate temperate humid Mediterranean

climate with hot summer

Cfa climate temperate humid climate with hot and relatively humid summer

Cfb climate temperate humid climate with warm and relatively humid summer

Csb climate Mediterranean climate with warm summer

• karst relief – general lack of surface water… …but…

PrecipitationPrecipitation:: 700-1500 700-1500 mm/amm/a

Vransko jezero Lake on the Cres Island

- the largest lake on Croatian islands- the largest accumulation of potable water in Croatia

- formed in karst depression- bottom of the lake about 61 m below the mean sea level- maximum depth is 74.5 m - surface of the lake is 5.75 km2

- contains roughly 220 million m3 of water

Lake near Njivice – Krk Island

- surface 0.6 km2

- bottom of the lake about 7 m below the mean sea level - catchment area 12 km2

- water level varies 1 - 2 m - used for the water-supply from 1963 - max. pumping capacity 5 l/s

Ponikve – Krk Island

- karst depresion (2200 × 50-300 m)- bottom of the valley – Quaternary sediments 44 m thick- surface 0.87 km2

- contains 2.65 mil. m3

- depth of the lake 6 m- pumping capacity up to 84 l/s

Large islands:

Few islands have adequate local water sources (e. g. Islands of Krk, Cres, Lošinj, Vis)

Others depend on water from the mainland

Islands with substantial water resources developed modern economy based on mass tourism

Positive impact of tourism on demographic processes

0

100000

200000

300000

400000

500000

600000

700000

1999. 2000. 2001. 2002. 2003. 2004. 2005. 2006. 2007. 2008.Godine

Bro

j tu

rist

a Krk

Cres

Rab

Lošinj

Number of tourists on the large Kvarner Islands from 1999 to 2008

1857. 1869. 1880. 1890. 1900. 1910. 1921. 1931. 1948. 1953. 1961. 1971. 1981. 1991. 20010

5000

10000

15000

20000

25000

Godine

Bro

j sta

no

vnik

a

Krk

Lošinj

Cres

Rab

Population of the large Kvarner Islands from 1857 to 2001

Main problem – water shortage during the high touristic season

e. g. Novalja on Pag Island

ca. 3,500 permanent inhabitants> 50,000 people during the summer

e. g. Krk Island

Population:

Winter: ~17-20,000 domestics

Summer: 20,000 domestics 50,000 weekend visitors 50,000 tourists

120,000 total

Water consumption during the year on Krk Island

Small inhabited islands:

Water supply from local sources, questionable water quality, salt-water intrusion during the summer

Lack of link with the waterworks on the larger neighbouring islands or on the mainland

Many small islands depend on water-supplying ships

Water shortage – the main obstacle for touristic development; negative impact on demographic trends

Possible alternative solutions: desalinationwastewater treatmentrainwater usagewater from submarine springs (vrulje)

Most solutions are not cost-effective

0

200

400

600

800

1000

1200

1400

1600

1999. 2000. 2001. 2002. 2003. 2004. 2005. 2006. 2007. 2008.

Godine

Bro

j tu

rist

a

Unije

Susak

Ilovik

Number of tourists on the small Kvarner Islands from 1999 to 2008

1857. 1869. 1880. 1890. 1900. 1910. 1921. 1931. 1948. 1953.1961. 1971. 1981. 1991. 2001.0

200

400

600

800

1000

1200

1400

1600

1800

Godine

Bro

j sta

no

vnik

a Ilovik

Unije

Susak

Vele Srakane

Male Srakane

Population of the small Kvarner Islands from 1857 to 2001

Threats:

Sea-level rise →

Consequences

• changes in surface water quality and groundwater characteristics• increased coastal erosion and coastal habitats• increased flood risk and potential loss of life and property• impacts on agriculture and aquaculture through decline in soil and water quality• loss of nonmonetary cultural resources and values• loss of tourism, recreation, and transportation functions

Demographic and economical pressure →

Consequences

• increased water consumption• water shortages during summer • decreased water quality• high risk of pollution• heavy impact on overall economical and social development

Conclusions:Relatively high precipitation (700 mm – 1500 mm)Karst relief – water rapidlly infiltrates undergroundLarge islands

- significant water resources - development of modern tourism-based economy- positive demographic trends- seasonality of water consumption- possible water shortages during summer months

Small islands - inadequate local water resources - low quality of water- underdeveloped tourism- negative demographic trends

Potential threats: sea-level rise; demographic and economical pressure

Thank you for your attention!

Zlatni Rat beach – Brač Island