Water Supply on Croatian Islands – the impact on tourism

1. Water Supply on Croatian Islands – the impact on tourism Ante Blaće, anblace@unizd.hr Branimir Vukosav, bvukosav@unizd.hr Robert Lončarić, rloncar@unizd.hr Department of Geography University of Zadar 14th European seminar on geography of water Cagliari, 26 June – 7 July 2011

2. 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

3. 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

4. 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

5. Natural features Geology • 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

6. Climatic settings • 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 Precipitation:700-1500 mm/a • karst relief – general lack of surface water… …but…

7. Vransko jezero Lakeon 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

8. 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

9. 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

10. 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

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

12. Population of the large Kvarner Islands from 1857 to 2001

13. Main problem – water shortage during the high touristic season e. g. Krk Island Population: Winter: ~17-20,000 domestics Summer: 20,000 domestics 50,000 weekend visitors 50,000 tourists 120,000 total e. g. Novalja on Pag Island ca. 3,500 permanent inhabitants > 50,000 people during the summer Water consumption during the year on Krk Island

14. 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: desalination wastewater treatment rainwater usage water from submarine springs (vrulje) • Most solutions are not cost-effective

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

16. Population of the small Kvarner Islands from 1857 to 2001

17. 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

18. Conclusions: • Relatively high precipitation (700 mm – 1500 mm) • Karst relief – water rapidlly infiltrates underground • Large 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

19. Thank you for your attention! Zlatni Rat beach – Brač Island