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14 2.4.2 Miocenic calcareous aquifer in the area of Ragusa It is divided in: a) limestones in the area of Syracuse, approximately 630,8 km 2 wide; b) limestones in the area of Ragusa, approximately 467,7 km 2 wide. They show an elevated permeability and they are situated in zones with precipitations between 800 and 1100 mm per year. They contain an almost continuous stratum (in the porous layers and/or in the fractured ones) drained by a karst net developed all along the fault lines. The aquifer’s thickness can vary between 100 and 300 m. 2.4.3 Volcanic aquifer in the area of Lentini It develops along the basin of Lentini and it also involves contiguous basins on a surface of 440 km 2 ; it shows moderate permeability. The area of recharge is compressed among the quotas 200 - 600 m and the precipitations are 550 - 800mm per year. The average thickness of the aquifer is approximately of 200 m; towards north the thickness of the vulcanites can sometimes go over 500 m. Permeability is limited to some parts of the vulcanites (lapilli, breccias, fissured lavas, intercalated calcareous layers). The aquifer is partially drained by the hydrografical net; the aquifer’s exploitation is now performed through numerous wells dislocated in the zone of Francofonte, Palagonia, Lentini. As a result, this aquifer appears in phase of overexploitation. 2.4.4 Plio-quaternary sandy-calcarenitic aquifer It essentially develops in the following areas: - area of Victoria-Caltagirone: outcrop of about 110 km 2 ; - area of Piazza Armerina-Mazzarino: outcrop of about 840 km 2 ; - coastal plain from Trapani to Sciacca: outcrop of about 800 km 2 ; - Agro of Palermo, from Castellamare del Golfo to Termini Imerese: outcrop of about 430 km 2 . The most important basin, for extension and resources, is that of Victoria. It must be quoted, for memory, even the small outcrop of Licata-Gela, Agira, and Regalbuto, Augusta, and Syracuse and Avola. From the point of view of the morphology, the zones of the calcarenitis constitute some plains and some plateaus relatively of low quota (inferior to 160 m) divided into plates by the hydrographical net. Formation is moderately permeable. Its thickness varies from 50-100 m in the basin of Victoria from 10 to 50 in the area of Palermo. It does not overcome 100 m in the coast plain from Trapani and Sciacca, instead it can reach 200- 250 m in Piazza Armerina and Leonforte. Rainfalls in these zones are on average low (from 500 mm to 700 mm per year) but some calcarenitic plates receive also a side supply by the limestones’ aquifers (areas of Syracuse, Victoria, Trapani, Palermo, Termini Imerese).
15 The aquifer is generally modestly deep and continuous; this explains the very numerous works of extraction that affect it, particularly in the zones of Vittoria, Palermo, Termini Imerese and Mazara del Vallo. It also occurs a certain drainage of the aquifer from the rivers and an outflow towards the sea in the coastal zones. However, the quantity of available water appears still reduced and further extractions do not seem to be possible. 2.4.5 Alluvial aquifer Alluvial water strata follow the course of the principal valleys. Floods are not significant in terms of aquifer recharge in the area of Trapani, along the Belice, along the Gela River because of their slimy nature and the consequent reduced permeability. Moreover, the waters’ salinity limits particularly the possibilities of use of the Platani alluvial stratum and the southern Hymera. On the contrary the alluvium of the northern slope of the island; the alluvium of the Simeto and the Plain of Catania; the alluvium of the river in the areas of Messina; the ancient alluvium of the Acate; the ancient alluvium of the Plain of Milazzo, provide low salinity water. 2.5 Groundwater resources in Sicily: Quality Aspects The heterogeneity of the underground water resources distribution and the variability of rainfalls coupled with recurrent dry years imply that Sicilian water resources may be insufficient to meet demand in several areas of the region and in several periods of the year. This has led to overexploitations of a number of sub-surface water resources, especially in the costal areas, where sea water intrusions are already in place (INEA, 2000). For these areas it is pointed out: a) general lowering of the piezometrics, to up to 10 m varying according to the zones; b) mineralised waters with values of conductibility progressively increasing; c) in certain zones (Plain of Colli, Cruillas, Bagheria and coastal area) elevated concentrations of chlorides, d) symptoms of sea water intrusion; concentrations of nitrates increasing in some wells; c) symptoms of a certain interference with fertilizers and pesticides or sewers unloading. According to Brucculeri et al. (2002) the qualitative situation of the aquifers inscribed in the study area can be summarized as follows:
Page 1 and 2: Ben-Gurion University of the Negev
Page 3 and 4: Abstract I The Sicilian water balan
Page 5 and 6: Tables of contents 1 INTRODUCTION 1
Page 7 and 8: Figures and tables V Figure 1 - Con
Page 9 and 10: 1 1 Introduction The Sicilian water
Page 11 and 12: 3 1.2 Water Balance Assessment One
Page 13 and 14: 5 In the initial process of any wat
Page 15 and 16: 7 almost exclusively with the use o
Page 17 and 18: Figure 2 - The study area 9 2.2 Cli
Page 19 and 20: 11 Figure 3 - Rainfall distribution
Page 21: Figure 6 - Qualitative features of
Page 25 and 26: 17 2.5.1 Potential vulnerability 5
Page 27 and 28: 3 Methodology 19 Two different mode
Page 29 and 30: 21 The objective function is subjec
Page 31 and 32: 23 to the output. This is not the c
Page 33 and 34: Ri = Runoff, rivers, lakes, reservo
Page 35 and 36: U j = s ∑ r = 1 u r 27 for r = 1,
Page 37 and 38: 29 C = smoothness of the internal p
Page 39 and 40: 31 The resulting polygons of every
Page 41 and 42: 33 c) The location of supply nodes
Page 43 and 44: 35 In the network made of 13 arcs t
Page 45 and 46: 37 and 600 mm per year. Springs and
Page 47 and 48: 39 Agricultural 13.4 4.4 - - Na 17.
Page 49 and 50: Basin: TELLARO Code: 19086 Area: 38
Page 51 and 52: 43 plant: and the Fiumara Grande an
Page 53 and 54: 45 total balance (table 14) of the
Page 55 and 56: 47 Table 15 - Arc length, and eleva
Page 57 and 58: 49 4.5 The Costs of Transshipment T
Page 59 and 60: 51 Figure 16 - Transhipment optimal
Page 61 and 62: 53 general equilibrium between the
Page 63 and 64: 55 6 References Agnew C. and Anders
Page 65 and 66: 57 Commissario Delegato per l'Emerg
Page 67 and 68: 59 Peel M. C., Finlayson B. L., and
Page 69 and 70: ANNEX A Transportation script MODEL
Page 71 and 72: ANNEX C Global optimal solution fou
Page 73 and 74:
65 Global optimal solution found. T
Page 75 and 76:
Page 77 and 78:
Page 79:
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