1 on New Strategy of Water Supply in Vojvodina Province , Yugoslavia

The great intensity of groundwater exploitation for water supply in Vojvodina Province in Yugoslavia has been provided from deep aquifers. More than 5.5 m/s comes from those aquifers, which belong to a subartesian and artesian type, and from depths varying from 60 m to more than 250 m. Due to intensive long-term groundwater production, the actual pumping levels at numerous deep wells, used for supplying cities, have declined more than 30 m. It is evident that problems of over-exploitation of deep aquifers in Vojvodina can not be efficiently resolved by continuing such groundwater stressful pumping regime. Therefore, it is necessary to initiate an approach to a new strategy for water supply by the powerful systems of free aquifers in the riparian zones of the Danube river and other rivers in the Province. Recently it was proved that there are great possibilities for using groundwater at Danube river riparian zone known as KovinDubovac sector. It’s renewable annual reserves of groundwater surpass the present exploitation capacities of all facilities for water supply in Vojvodina. The new strategy of water supply will be contributed by radical restriction of groundwater exploitation of deep aquifers and by saving the available reserves from further abuse. The new approach will be powered by intensive application of modern systems analysis and decision support techniques followed by systematic assessment of groundwater regime and dynamic balance with surface waters by advanced mathematical modeling and simulation. INTRODUCTION Based on a recent investigations of groundwater resources in Vojvodina Province locasted in northern Yugoslavia, the term ‘major aquifer complex’ has been introduced to denote systems of water-bearing layers important in determining groundwater balances. Those are primarily sandy-gravel and sandy layers extending over great areas of Province. Their water reserves are generally of good quality as far physical and chemical characteristics are considered and therefore were increasingly used for municipal supply and for different other purposes such as agricultural irrigation, industrial supply etc. Quaternary sediments are the primary aquifers: (1) Holocene and Alluvial sandy-gravel layers and recent Pleistocene terraces sand overlaying gravel, as well as eolian layers of sands and loess, (2) older Pleistocene sands and gravel with alevrites or clays, i.e. polycyclical fluvial sediments (3) Eopleistocene and Paludian layers of gravel sands and clays which make overlie Pontian sands and clays. The major part of water demand in Vojvodina has been supplied by exploitation of deep artesian and subartesian aquifers with discharge rate slightly over 5 m/s. Those aquifers are identified at depths varying from 60 m to over 250 m. Due to intensive long-term exploitation of groundwater, the actual dynamic levels at numerous deep wells used for supplying urban areas are in a permanent decline (10 to 30 m). Waters in those aquifers are significantly over-exploited (Mijatovic, 1998). Projected water utilization to 2020 indicates that dynamic levels in deep aquifers will reach critical levels. At this point there is a direct menace of pollution from shallow phreatic aquifers and from the intrusion of deep mineralized waters as well. The new strategy of water supply in Vojvodina is foreseen as the radical restriction of groundwater exploitation of deep aquifers. Instead, conjunctive use of surface waters and ground waters in alluvial basins extending along major streamflows in Vojvodina is identified as huge new water source to be efficiently exploited in the next century. This renewable source of drinking water has to be investigated by modern systems approaches and sophisticated software. This is due to a complexity of interconnections of alluvial aquifers, river-beds and channels, and multiple (more or less conflict) water needs and users – and particularly necessity of long-term evaluation of local and regional goals, priorities (interests), economical, environmental and other effects. MAJOR AQUIFERS IN VOJVODINA Hydrogeological investigations in the plain of Vojvodina for decades were traditionally undertaken and primarily focused on groundwater facilities for water supply. They did not provide sufficient information about basic hydrogeological parameters and boundary conditions of shallow and deep aquifers.