Page 6 - Barrocu_2003

ITALIA
yield of 6.8 m3/s has been estimated for the car-
bonate aquifers of the Madonie mountains, whose
springs partly supply the aqueduct of Palermo,
and the Hyblean mountains, partly discharging
into the Recent coastal aquifers of Priolo-Augus-
ta, Lentini and Syracuse on their south-eastern
borders.
On the coast of Syracuse, to the east of the
Hyblean mountains, the springs of Ciane yield
600 l/s, Fons Aretusa, 250 l/s and S. Calogero,
200 l/s. Altogether 163 springs have been inven-
toried on the southern slope, with a tota1 yield of
3.3 m3/s, and 168 on the eastern slope, with a total occa-Corr’e Pruna. Other aquifers of local impor-
yield of 1.7 m3/s. A feature of local, but consider- tance, up to 50 metres thick, are hosted in small
able, interest is the presence of Quaternary sand
and small ca1careous rocks spread over various
area of the islands on the Pleistocene argi1laceous
covers. They are found in the Marsala-Mazzara
del Vallo area, where the piezometric gradient is
1-1.5 %, and in the zone of Piazza Armerina, on
the Vittoria plateau, where 1286 logged wells are
situated with an estimated transmissivity of 3x10-3
to 10-3 m2/s.
Many of the small islands off the coasts of
Sicily (Eolie, Ustica, Pantalleria, Linosa) are also ous rocks of the Nurra, in the north-western tip of
of volcanic origin but the fresh-water lenses
occurring on top of the saltwater are fairly shal-
low and only constitute a minor groundwater
resource or are not exploitable at all.
The Campidano plain in the province of
Cagliari, the most depressed part of the main
Graben of Sardinia, filled with early Tertiary-
Quaternary sediments and interbedded volcanites,
hosts an important aquifer system, for the most
part supplied laterally through the composite tec-
tonic blocks delimiting the tectonic trough. The
Pleistocene and Recent areas consist largely of
shingle, sand and mud up to 200 metres thick. The
resultant aquifer, extensively tapped by more than
1600 wells, is of considerable importance for
local agriculture and municipal uses. The piezo-
metric surface has gradients in the order of 0.2%.
A major part of the groundwater flows towards
the Bay of Oristano and the remainder towards
the Bay of Cagliari. The total yield of the aquifer
system of the area of Oristano and Arborea-Santa
212
Giusta is estimated at 400-600 l/s, tapped through
hundreds of wells. In the Capoterra aquifer sys-
tem on the south-eastern edge of the Campidano
plain, an average yield Q=0.360 m3/s with a K=
1x10-2 to 4.5x10-1 cm/s and gradient of 0.3% have
been calculated. An estimated yield of a few hun-
dred l/s is tapped also from the aquifer system of
the western edge of the plain. In the delta plain of
the river Flumendosa, up to 200 m thick in its
middle part, an average fresh groundwater flow of
3.3 Mm3/year has been calculated, and a flow of
1.5 Mm3/year was evaluated for the aquifer sys-
tem of the contiguous delta plain of the River Pic-
delta plains along the island’s coasts.
Sardinia's calcareous rocks constitute major
aquifers. In the Portotorres area, near Sassari,
Miocene calcareous rocks contain a significant
aquifer, partly drained by the streams that dis-
charge into the sea, in the Anglona region. There
are more than 500 small springs with a collective
average yield of 0.45 m3/s, and a large number of
wells situated at the margin of the hilly areas. The
groundwater occurring in the Mesozoic calcare-
the island, is extensively exploited due to the
presence of numerous wells, the result being that
many of the springs have dried up, and part of the
groundwater discharges into the sea. There are 43
springs with an average overall yield of 200 l/s. In
the East of Sardinia there are numerous outcrops
of calcareous rocks, the largest being the karstic
massif of Dorgali, facing the Bay of Orosei.
These aquifers represent the only important
ground-water resource in the area. Some springs
have flow rates of 20-120 1/s. There are 155
springs with an overall average yield of 1100 l/s.
Between 400 and 750 1/s of groundwater are
discharged directly into the sea. A total yield of
25 Mm3/year and reserves of 144 Mm3 have been
estimated. In the Iglesias region, to the west of
Cagliari, there are about 100 logged springs with
a total average discharge of about 500 l/s from the
karstic aquifer in the Cambrian metalliferous
limestones, representing the most important lead