EI Problems of Water-Supply in the Coast-Insular Area of the Zadar Region Zeljka iiljkoaiC, Martin Glamuzina, Nikola Glamuzina Fdcult.:l of Arts in Zadar, Depttnent of Geogfttphll, Obala kralja Petra Kreimira IV, No.2, Zadqr, Croatia Abstract The sifuation in economic development, especiallyin toudsm and agrrculture, as well as de- mographic changes in the Zadar region are closely connected to inJras tructure development, particularly with water-supply. The intention of this arhcle ls to warn abouL the ursustainable condition in water supply of the insular area. Applyingthe statistical data, analyzing the existing condition and using the method ofcom- padson, very contradictory condition in economizjng the drinking water in coastal and in sular parl of the region has been established The coastal part has been connected to the water-supply system of the Zrmanja drainageba- sin i.e to the regional water-supply system of the Northern Dalmatia, and uses local spdngs, whrch enables economic and demographic development of the coastal seLtlements On the other hand, the islands of the Zadar archipelago belong to the group of the least developed and socially most neglected parts of the country. The quahly water supply is a very importantprecondition for the revival of the insular area Because of this reasons, the authors think that the quahty and constant supply of the islands is the basis for the development of touism alrd other economic acrivities, particularly agri- culture lntroduction Researches and Resu lts Quality and constant water supply of a certain area lnsular Part of the Region is a precondition for demographic and economic de- velopmenl The area of the Zadar archipelago belongs to Csa Present condition of the Zadar region is marked type of climate with precipitations ranging from 800 to with discordance between coastal and insular atea. 1000 mm. The main raining period is in the colder parL ofthe year, from September to December. According to While the regional water-supply system enables the accessible data (Table 1), observir.rg monthly and constant and quality supply as well as the revival ofthe annual values within the observed area, there are sig- economic activities, the insular area still stagnates in its nificant differences in dispositlon and quantity development. of the precipitations. The average amual values rise from The lack of regular water supply is a crucial prob- outer, open-sea part of the region towards the coastal lem that provoked depopulation and stopped the de- sequence of islands. velopment of the economy. At the meteorological stahon in Sali (Dugi otok) There are no surface flows ilr the insular area, and the annual quaniity of precipitation in the period be- brackish water springs are very rare. The presenL way tween 1961 alld 1990 was 824 mm, while on the island of water supplying by cistems, raillwater and watet of Vir, which is a coasial jsland, the quantity ofprecipi- carders does not meet the local people's needs, let tation in the same period reached the value of 985 mm. alone the needs of the tourists in the summer. The quantity of precipitations decreases from the is- lands in the northernpart ofthe archipelago (the island Period biol, Vol 102, Supplement 1,2000 379 'LgUXorKd* LITTORAL 2000 - Responsible Coastal Zone Management 1 1 month and annual quantities of precipitations in the insular part of the Zadar region in the period 1961-1990 Table - Average '*ts* SILBA 93 15 70 6J 64 s7 19 69 94 86 133 92 938 58 OLIB a7 a2 71 65 60 56 36 67 97 86 132 96 934 59 t5T 86 77 70 66 56 49 37 66 95 77 118 93 889 59 MOLAT 79 71 6A 61 47 53 30 66 93 70 119 91 848 59 92 a3 80 71 64 51 38 67 9a 110 133 97 985 60 ZADAR 77 12 74 60 61 52 35 63 98 112 118 94 915 60 UGUAN a4 76 75 66 58 56 42 59 97 110 120 94 938 60 s4't ls BRBINJ 86 74 J2 65 55 51 39 53 92 106 120 93 906 61 r. titrd vEU rZ 7s 66 67 s8 50 42 35 58 86 98 114 88 837 61 Ib 77 90 108 90 424 62 SAL| 83 68 69 5s 48 49 30 57 nrE fF Table 2 - The conditron of water supply on Zadar islands &r d t-.a b-. SILBA YES YES 4 WELLS Water supply network local cisterns id OLIB YES YE5 4 WELLS 5prin9 of brackish water b finl€d PREMUDA LOCAL YES YES 3 WELLS construction oJ supply system Th iKARDA 3 WELLS dd tsT LOCAL YE5 YES 3 WELLS construction of supply network IG MOLAT LOCAL YE5 YE5 12 WELLS Construction of new water reseNoir &E' ZVERINAC YES YES 2 WELLS YE5 YES 11 WELLS l SPRING tz E-1 WELLS YE5 YES 2 nDEd SESTRUNJ YES l WELL *tt RIVANJ SESTRICA V YE5 oSUAK YE5 BABAC l WELL VRGADA 4 WELLS r.f of Silba 938 mm) towards the southem insular series habitants are left to self managing. This analysis in- - and (Sali - 824 mm). cludes the northem islands (Silba, O1ib, Prernuda, Mo- (Dugi dis The islands in whose geological structure prevail lat), the area of the outer series of islands otok) (Ugljan, Vir). Cretaceous Limestone and dolomites (OIib, Silba, and the coastal series of islands Premuda, Zverinac, Sestrunj, Rivanj, Skrada,Molat) to- The island of OIib is made ofCretaceous limestone gether with local appearances oI Eolic limestone (the and dolomites with smaller zones of Eocene limestone island oI Olib) and Eolic marl (Silba), don't have sur- in the northeast, while the narrow dolomite zone faceflows. Theporous surface enables a direct draining stretches ftom northwest to southeast. Such structure off of water into the undergrould The consequence of oI the ground causes the absence of surface flows and this situation is the absence of the springs with drink- enables the appearance of smaller puddles in the dolo- ing water, and the appearances of the brackish water mite zone. There are a few springs ofbrackishwater on are very rare. Such salty water has been spotted on the the island among which the one found in the Sibenska islands: Silba, Olib, Molat, IZ, Premuda, Skarda, Ist, Bay is the largest. As a result of this situation the sup- Rava, Sestrunj, Zverinac, Vrgada and Babac (Table 2). ply exclusively depends on the transport ofwaterby a Although a certain quantity of these waters could water carrier and individual ci'terns. be used as technological water or in the households, The majorpart of Silba is made ofCretaceous lime- the main problem is [hat there are no machines for pu- stone, except in the southern part where there are dfying or for desalinization of these watels. Eocene marls. ln wintertime, when the quantity ofpre- A detailed analysis of the condition of the maller cipitations is 58% of the total annual quantity, the in- islands of the Zadar archipelago indicates very ne- habitants supply themselves mainly by rainwaler. On glected condition of the water supply and the local in- the other hand, in the summer time the water carier 380 Penod biol, vol 102,supplement l, 2000 i i -(ovrc et at.: Water-5upply in Coast-lnsu ar Area of Zadar Region ]e period 1961-t 990 ] 23 -- - - .q .a strLrcture causes + on ihe slands prevails + the sLrpply is limited to rain- + the condition do€s not me€t -:::.< oi surface flows brack sh w.ter water and/or water carrier th€ ne€ds of ihe loca inhabitants ]n,.,"r % tI11.9;t =-__.\ '58 59 59 HE UNsOLVING OF THE PROELEMS OF WATER SLJPPLY CAUsES DEMOGRAPH C EMPT|NG 59 oF THE SLANDs AND THE STAGNATION OF THF FCONOMIa DFVFIOPMFNT Graph 1 Based on the a ready estabLished, it Ir possible to paft t'(l-^ - dlfferent ate several cruc al characteristics of ihe coastal of the regloni 60 60 -r:rorts the supply. The island has a water supply net- the only mean of water supply is also the waier stored 6l . -.1( that is connected to the local cisierns in the cisterns either as the rainwater or water trans- ported by ships. (Graph 1) 62 The island of Premuda has a similar strucLure; .:r.el\; it is made of Cretaceous linestone, and on the As ithasbeen stated earlier, depopulation of the is- r--iiheastern and souLhwestern side of the island the lar-rds additionally conlributes to the problem of water :r. .oYes end with slrall overflowed bays In the bay supply, especially on those, traffic isolated islands with :: Lazi there are springs of brackish water Premuda almost none or very weak cconomrc activities. There cistelns .:s a local water supply system that includes two local fore, ri is no surprise that the most neglected islancis are ::i several private cisLerns. The supply in the summer both those affected by depopulation and those h,iih a - . 'ipd to ihc re8u la r : r.rr r I of rn arcr i.r rrier negative population growth, with a domination of the old people and/or singles (Table 3). Only Ugljan and The island of Molat rs made of l-ower Creiaceous Dugi otok can be treated as potential development ar- rrk :... Eocene limestone, which indicates the lack of sur, eas - the island of Ugljan because of its nearness Lo the -:ie floils and the springs of drinking rl'ater. The three regional center (i.e. Zadar) and because of the potential ::E rtells have a capacity ihat is insufficient for a safer ndustrialization (ship repairing yard Lamjana) and .el:-supply (less than 0,1 l/sec).