Pantaleone DE VITA 3. Editorial director: Rodolfo ..... ted by the karst sinkholes and swallow holes buried under alluvial deposits, which are still hydraulically ...
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ENVIRONMENTAL PROTECTION AND TECHNICAL SERVICES AGENCY
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DEPARTMENT OF GEOPHYSICS AND VOLCANOLOGY
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Scientific directors:
Pietro CELICO3, Pantaleone DE VITA3, Giuseppina MONACELLIs, Anna Ros,q SCALISES, Giuseppe TRANFACLIA5 Authors of regional hlzdrogeological descriptions and of cartographic interpretations:
Vincenzo ALLOCCAl, Fulvio CELICO2, Pietro CELICO3, Pantaleone DE VITA3, Silvia FABBROCINO3, Cesaria MATTIAT, Giuseppina MONACELLIS, Ilaria MUSILLII, Vincenzo PISCOPOI, Anna Rosa SCALISEs, Gianpietro SUMMAT, Giuseppe TRANFAGLIAS Scientific editor: Pantaleone DE VITA
3
Editorial director: Rodolfo LAMA
s
r)Doctorate of Engineering and Environmental Geology University of Naples "Federico :)Deparlment of Environmental Sciences and Technologies University of Molise r'Deparlment of Geophysics and Volcanology University ol Naples "Federico II"
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-
r)Department of Environmental Sciences University of Viterbo "La Tuscia" 5)Environmental Protection and Technical Services Agency (A.PA.T.)
1. PREFACE
The European Commission with the decree n. 2231 of July 3l"t 1997 approved the implementation of the programme INTERREG IIC, Section "Ter:ritorial regulation and contrast to drought", to be carried out in those Italian regions belonging to Objective I (Molise, Campania, Puglia, Basilicata and Calabria), delegating the coordination of the program to the Department of National Technical Services (D.S.T.N.). The D.S.T.N., in the function of the executive responsible of subprogram 1, "Hydrological cycle analysis in the regions of objective 1", specified the pu{poses, proposing the project: "Assessment of the Southem ltaly's groundwater resources and the improvement of the monitoring piezometric network belonging to the Hydrographical and Tidal National Service (department of Naples)". The D.S.T.N. assigned this study, through a convention, to the Department of Geophysics and Volcanology of the University of Naples "Federico II". Since October 6th 2002 the jurisdiction and activities of D.S.T.N. were assigned to the Environmental Protection and Technical Services Agency (A.P.A.T.), (D.P.R. n. 207 of August 8th 2002).
The study program was subdivided into different objectives, in accordance with the different scales of analyses, with the scope of deepening the hydrogeological knowledge in the continental part of Southern Italy, up to deflning specif,rc features fundamental for the setting up and the management of a regional monitoring network. Specifically, first among the objectives was the "definition of a summary of the scientific knowledge concerning the groundwater resources and their use in Southern ltaly", based on the bibliographic hydrogeological data gathered from the regions of Objective I. The most important interpretative products to which this phase of the analysis was finalised include: . A hydrogeological map, 1:250.000 scale, showing all hydrostratigraphic units,
which due to their extension, typology and mapping possibility have some importance in the regional hydrogeological context. In this map all the hydrogeological structures for which hydrogeological studies are known in the literature have also been mapped.
' Illustrative
notes, accompanying the map, which summarise the evolution and the state of knowledge for each hydrogeological structure.
2. THE
ACQUISITION AND ORGANISATION OF BIBLIOGRAPHIC DATA
The reconshuction of a homogeneous and complete groundwater resource framework of the continental part of Southern Italy was achieved through the acquisition of most scientific papers dealing with hydrogeological studies in Objective I regions. Moreover, published and unpublished hydrogeological studies commissioned by various institutions, which manage the territory were also analysed (Municipalities, Provinces, Drainage and Irrigation OfIices, etc.). The bibliographic research, in addition to the aforementioned sources, was also supported by unpublished results of hydrogeological researches, carried out in universities and research institutions, such as doctorate theses, degree theses and intemal reports of research institutions. The bibliographic research resulted in the gathering of 572 papers on the studied regions. On the basis of the main themes analysed, the context of such studies extends into the various fields of hydrogeology and of groundwater management, ranging from the reconstruction of sketches of groundwater flow to the estimation of the groundwater yield of hydrogeological structures, from studies concerning physical and chemical characteristics of groundwater to the problems related to exploitation design, to the estimation of the intrinsic wlnerability of aquifers, and so forth. ln order to homogenise and to make the bibliographic data rapidly accessible, the filing operations were standardised using a relational database, specifically designed with a high number of informative hydrogeological levels. Such procedure permitted the filing of diflerent typologies of data, derived from the papers analysed, into the following 12 tables: a) identification of study; b) administrative location; c) physiographic setting; d) geological and hydrogeological characterisation; e) contents and results; f) springs; g) groundwater bodies; h) wells and instrumented boreholes; i) rivers; l) hydrogeochemical analyses; m) rainfall data; n) air temperature data. The information levels were distributed in the aforementioned tables in 123 data fields, according to the typology of information they represent. The structure of relations between tables was elaborated in a bondless way, resulting in biunique bonds between each single table and all others, aiming to permit free access to all data (Fig. 1). A particular approach was adopted for the gathering of information on springs, which are often named in different ways in difflerent bibliographic sources. In fact, in many cases, the identification of a particular spring is not unique, because different
names have often been attributed to the same spring in neighbouring localities. Moreover, the collection of spring data was arranged in order to not only show the principal springs, with a discharge superior to 0,050 m3/s, but also to evidence those of less relevance, i.e. with a discharge superior to 0,001 m3/s, which give important information on groundwater flow sketches in hydrogeological structures of minor regional relevance. Therefore the information collected for each spring were validated by means of a crosscheck among the sources. This control was carried out, including the map position, referring to the Military Geographic Institute's (I.G.M.) official cartography, 1:25.000 scale. From the analysis of the spring discharge information there appeared temporary gaps in the data, which unfortunately indicate unsystematic discharge measurements. In fact the discharges of most of the main springs are known only by two measurements approximatively corresponding to the minimum and maximum values, during a single hydrologic year. Instead, for springs with less relevant discharge there only exists data collected during the 30s by the Hydrographical Service. The schematic analysis of the state of exploitation of groundwater resources was completed both through the mapping of the tapped springs and with the survey of the principal well fields utilised by the regional aqueduct systems.
3. RE GIONAL HYDROGE OLOGICAL CHARACTERISATION
The geological and structural complexity of the regions object of this study results in a high hydrogeological heterogeneity of the territory consequently making its hydrogeological characterization somewhat problematic, including a cartographic representation through the establishment of basic hydrogeological units. As well known, in contrast to geological units (lithostratigraphic, biostratigraphic and chronostratigraphic) for which unique nomenclature criteria exist (ISSC, l9l6), the stratigraphic units utilised in hydrogeology, defined aquifers by Mpruzsn (1923) and subsequently hydrostratigraphic units by Maxev (1964) and LoHvaN (1912), are examples of units for which currently there is a lack of unique criteria of nomenclature, which would permit formal classifications. Specifically, because of the lack of international rules concerning the institution of hydrostratigraphic units, the fundamental hydrogeological units have been instituted by the assumption of the concept of the hydrogeological complex (CrvIra, l9l3; 197 5), defined as a "series of lithotypes with a prevalent type of permeability, a grade of hydraulic conductivity variable in a restrict range, and a proved spatial and structural unity", subsequently improved incorporating those guidelines indicated by UNESCO and WMO (1977).In particular, the establishment of the hydrogeological complex concept was conditioned by the need of having to map at a 1:250.000 scale, which would have prevented the use of more specific criteria (OwrN, 1987; JoncENSEN and RosrNSHEIN, 1987; LeNsv and DevmsoN, 1986). Therefore, the subdivision of the territory examined into hydrogeological complexes was carried out respecting the following three fundamental criteria, which permitted to obtain a homogeneous representation, at the same time incorporating a high hydrogeological detail, in keeping with the scale, and the respect of geometric relationships among the lithostratigraphic and hydrogeological units (UNESCO and WMO, 1917). a) Reference to a common regional geological scheme, sufficiently detailed for the scale requested (1:250.000). For this purpose, use was made of the geological scheme reported in the "Geological Map of SouthernAppennines", presented at the 74th Congress of the Italian Geological Society held in Sorrento in 1988 (BoNenor et a1., 1988). In this scheme all the geological data from the Southern Apennines
and the modern interpretations dealing with the regional settings were condensed and homogenised. This geological map, even if it is not updated with recent geo-
logical studies that have modified the chronostratigraphic position of some lithostratigraphic and tectonic units, at the moment represents the more consistent geological framework of the Southern Apennines. The map in question, even if it does not cover the entire area studied, has in any case prepared a guideline with which the data of the geological map, 1:100.000 scale, of the Molise, the Puglia and part of the Calabria regions (Geological Map of Italy sheets no.'. 202, 203, 204, 213, 214,2I5,220 and 221), and the geological map, 1:25.000 scale, of Calabria (Geological Map of Calabria - 167 sheets) have been uniformed. b) Institution of hydrogeological complexes, aimed at maintaining as high a detail as possible, in accordance with the knowledge of the hydrogeological characteristics of the various lithostratigraphic and tectonic units, which constitute the Southern Apennine and as required by the mapping scale. c) Institution of hydrogeological complexes according to the regional geometric relationships between coffesponding lithostratigraphic and tectonic units. This criterion has permitted the distinction, for example, of the Mesozoic carbonate series in different hydrogeological complexes, related to corresponding stratigraphic-structural units. Likewise the complexes related to the paleogeographic units of different basins have been distinguished. Every hydrogeological complex was assigned with its basic hydrogeological features, including the type of permeability and the relative permeability grade and
the Potential Infiltration Coefficient (C.I.P.). As understood from the literature available, the C.I.P. was attributed to the hydrogeological complexes, which form the most important aquifers (limestone, dolomitic, alluvial etc. aquifers), from the experimental results based on the hydrological budgets referred to well defined hydrogeological structures (BoNr et alii,1982; Crrtco, 1988). The hydrogeological map, 1:250.000 scale, in which all the relevant complexes in the regional geological framework have been mapped, represents the most important interpretative product of this study. Therefore a methodology for classification of aquifers, which permits to distinguish the lower grade of permeability units as well, was adopted. The hydrogeological interpretation of the lithostratigraphic and tectonic units known from the literature for the Southern Apennine regions, allowed the distinction of 39 hydrogeological complexes for which the basic hydrogeological features have been described in detail (type of permeability, relative permeability grade and the potential infiltration coefficient): a) Quatemary complexes; b) Pliocene-Quaternary volcanic complexes; c) Pliocene-Quatemary marine complexes; d) Lateorogenic molasses complexes; e) Synorogenic turbidite series complexes; f) Paleogene carbonate series complexes; g) Mesozoic carbonate platform series complexes; h) Outer Basin Units complexes; i) Inner Basin Units complexes; l) Hercynian Calabrian Units complexes. The data of the outcropping areas of the hydrogeological complexes have been digitised in a vector format and transferred to a Geographic Information System (G.I.S.), georeferenced to the U.T.M. international system (Projection in the 33 zone). Moreover, through the association between hydrogeological database and graphical elements, in addition to the hydrogeological map, derivative maps of the type of permeability and the relative grade of permeability were also obtained (Fig. 2), as well as that of the potential infiltration coefficient.
B) ADN{.\IISTRATIVE LOCATION
G) GROLTND\\AIER BODIES
tD.
ID
Region Province
Groundwater body identifi cation
\lunicipality
N{aximum piezometric head (m.a.s.l.) Minimm piezometric head (m.a.s.l.) Ilydraulic gradient (o;) Location or the oulflow
BOREHOLES ID,
Location
Hydrogeological Unit 1 Structue Hydrogeological complex Measùrement pcriod Estimallon ol mean groundwater discha.ge (10' mrtyear) Dye expeiments (summary of results) Geophysical surueys (summary of resùlts)
C) PHYSIOGRAPHIC SETTI}iG 1D,
N{ounr or
Hi WELLS AND lNSTRUIENTED
Rieliel
Hydrographic basin
Notes
\\iell identification Location Spring identification Groundwaler body identilìcation Altifu te of measurements Depth (m) Number ofmeaswemeDts Maxjmum piezometilc head (m-a.s.l.) N{ean piszometric head (m.a.s.1.) Minimum piezometic head (m.a.s.1.) Transmissivity (m'/s) Specific capacity (mi,'s) Dye experiments (summary of results) Geophysical suneys (summary of resuÌts) Use
Withdrarval discharge (m',rs) Notes DJ GEOLOGICAL AND
lD. Unit i fomation Geological Summary Hydrogeological Unit / Structure
1)
Total area (kmr) Average C.l.P. (9,o) Hydrogeologìcal sunmary
E) CONTENTS
RIVERS
tD. Name
Hydrogmphìc basin lnvolved Hydrogeological structures Location of stream discharge measurements Number ofmeasurements Period or date of measurements Mdimum discharge (m'/s)
AND RESULTS
1D.
A) IDENTIFlCAIION OF STUDY
Contents and results sùmmary Hydrogeological Unit / Structure
ID,
Hydrogeological description Area (km')
Operator
Tlpe
Average C.l.P. ('lo) Growdeater recharge ftom surficial freshwater (m',/s) Mem neì rainfall (mm/yed) Mean actual infiltration (mn'year) Springs discharge (mì/s) Rivers discharge (ù'rs)
Autors
Mean discharge (m',rs) Minimum discharge (m'is) Dye experiments (summary of results) Use User Exploitated discharge (mr,/s) Notes
Year
Title Joumal or commifting institution Enclosed maps and relative scale
Groundsater outflows (mr1s) L) HYDROGEOCHEMICAL ANALYSES
Groundwster bodies exploitation grade (9;) Notes
ID. Idenrification of spring Identification of welì ldentilìcation of river
1D.
Date Temperatwe ("C) PH
Name
IDS (mgl/l)
Localion Altiture (m.a.s.l.) Hydrogeological Unil r Structure Hydrogeological complex Number ofmeasurements Measurenents period Maximum discharge (mr,ts)
Electrical Conductivity (ÈSlcm) Hùdness ('F) Na* (mg/l) K* (mg/l)
F) SPRINGS
Ca" (rrgll) Mg*- (ng1l) Cl' (mg/i) HCOr (mg/l) SO. (mgil) COr (mg/l) NO,' (ms/l)
Mean discharge (m'r's) Minimum discharge (mr,'s) Meiuer index (9'o) D"ve experiments (smmary of results) Ceophysical surve.vs (summary of results)
òrrO
Use User
(r)
0,.)
^D Anomalous
hydrogeochemical parameters (DPR 236i88): DLgs 152,'99
Iapped discharge (mr,/s) Notes
N) AIR TEMPER,{TURE DATA ID, Temperature gauge identifi cation Hydrographic basin
Altitute (m.a.s.1.) Functioning dùration (years) Mem yearfy air temperafure Notes
M) R{INFALL DATA ID, Raingauge identifi cation llydrogmphic basìn Altitute (m.a.s.l.)
Functioning peiod Functioning duration (years) Mean rainfall (m,/year) Notes
Fig. 1: Organisation o:f the relational database in thematic tables in which the hydrogeological data derivedfrom bibliographic sources have beenfiled.
4. APPLICATIONS AND PERSPECTIVES OF THE REGION,A,L HYDRO-
GEOLOGICAL CARTOGRAPHY The homogenisation and implementation of data in the Hydrogeological Map of Southem Italy permitted the creation of a basic instrument, which is fundamental for the interregional analysis of water supply. In fact, a correct management of water resources is possible only at the interregional scale, allowing the management of groundwater and surficial freshwater resources though the coordination between public and private institutions, in order to minimise possible reciprocal conflicts. In this view, the water resources available for exploitation could be organised in a river ecosystem compatible program (Art. 1, Law n, 36 January 5th 1994), especially in the great hydrographic basins characterised by high hydrogeological complexity. Specifically, in the framework ofthe growing current need for water, more detailed territorial hydrogeological analyses could permit the identification, by means of hydrologic budgets, of integrative groundwater resources for regional aqueduct
systems. In particulaq because of the almost whole utilisation of the principal springs fed by high permeabilisz grade aquifers, limestone and dolomitic limestone, possible integrative groundwater resources could be looked for in medium permeability grade hydrogeological complexes chiefly represented by porous quatemary aquifers, especially where they receive hydraulic feedings from adjacent hydrogeological strucfures ofa carbonate nature. This kind of research could be carried out applying, first, hydrologic budgets and, subsequently, specific hydrogeological studies. In fact, as one can see from outcropping areas, hydrogeological complexes with medium permeability grade occupy a very consistent part of the territory reaching 28.000 km2, which corresponds to the 45yo ofthe total area (Figs. 2 and3).
Legend
@ lllrl f-.a Xcdun Lor I mporvtar I
Fig.2: Map ofrelative peflneability glade.
The hydrogeological map of Southem Italy represents moreover a useful mana-
gement instrument for the possible updating of groundwatff resources database, also making use of hydrologic budgets applied to hydrogeological sffuctures or to hydrographic basins. Such possibility seems to be very important in order to manage the effects ofglobal climatic changes on the annual amount of atmospheric precipitations and their distribution during the hydrologic year, as recognised by the Scientific Community. For this purpose, the scale of the hydrogeological map (1:250.000), and the strucflre of the G.I.S., are sufliciently detailed for the implementation of the information conceming rain-gauges, temperature-gauges and river discharge-gauges, which are present in the territory.
200 0
f.ij1ffi--oMffi-= Fig. 3: Distributio of hydrcgeological re ced.for the d aused.fìte regions.
complexes in relalionship
l trith the relatùe permeability grade, dilJe-
5. SUMMARY OF THE HYDROGEOLOGY OF SOUTHERN ITALY
The hydrogeological comprehension of Southem Italy's teritory developed over the last years is the result of studies carried out primarily by the "Cassa per il Mezzogiomo" with Special Projects 26 ar,d 29, and by activities carried out by regional research centres and Universities. The wide teritory belonging to the five region of Objective I, Molise, Campania, Puglia, Basilicata and Calabria, includes most of the Southem Apennines, and as such is characterised by very heterogeneous and complex hydrogeological features, related to the variety of lithotypes of stratigraphic-structural units. As known, these units can be correlated by means of a paleogeographic reconstruction to a scheme represented by carbonate platform domains and by interposed basin domains which remained undisturbed until the begiruring of the Cenozoic (D'ARGENIo, 1988). Subsequently, Miocene tectonic phases involved these paleogeographic units in the orogeny, deforming them, now constituting thrust nappe structures. The great variability of the lithotypes, which form these units, as a result of the very different characteristics of their own sedimentary environments and to their
tectonic deformations, strongly condition the hydrogeological features of such terrains. However, as far as the analysis of hydrogeological characteristics are concerned, these units can be arranged in five great hydrogeological groups. In order of importance in the regional water supply, these hydrogeological groups are: a) Mesozoic carbonate series which constitute the main mountain groups of the area studied; b) Pliocene-Quaternary alluvial and epiclastic deposits, which fill the valleys making up the alluvial and coastal plains; c) volcanic products belonging to Pliocene-Quatemary eruptive centres; d) Paleozoic Calabrian igneous and metamorphic rocks which form the main mountains of the CalabrianArc; e) CretaceousCenozoic marine basin series, which make up the minor mountains and hills of the Southern Apennines. For each of these groups their general hydrogeological characteristics have been summarised in the following paragraphs. For further information concerning hydrogeological structures, a consultation of the illustrative notes to the hydrogeological map is recommended. 5.1 CansoNATE
sERTES AeUTFERS
The carbonate massifs form the highest mountains and the most important aqueduct water supplies of the whole of Southern ltaly. The features of the groundwater flow are sufficiently known in these aquifers, in fact the relationship with the lithostratigraphic characteristic of Mesozoic and Cenozoic series, the influence of the Miocene and Pliocene-Quatemary structural settings and the karst phenomena have been studied. The development of such knowledge increased with the acquisition of data following the construction of major tunnels and aqueducts in Southem Italy, providing hydrogeological information both on regional (Crrrco 1978; 1983; BoNr et al., 1987; CorEccHta & Macnr, 1966; Gn-rssr, 1914) and local scales. Carbonate Mesozoic rocks are the main components of these aquifers, highly
fractured due to their brittle mechanical behaviour and tectonic stresses. Furthermore, due to their chemical composition, these rocks are subject to karst phenomena, through which percolating water enlarges the original fracture network. This network of discontinuities gives these mountains a very high infiltration capacity, permitting groundwater flow and the runoff respectively to constitute the main part (85% + 95oÀ) and the minor part of the effective precipitations. These carbonate mountains can be considered to be very large reservoirs in which the general basal groundwater flow is controlled by the geometric relationships with adjacent geological units, in addition to the main inner structural discontinuities. The carbonate aquifers of the Molise, Campania, Basilicata and Northem Calabria represent the main drinking water sources of Southem Italy, giving a mean water yield of about 4.100 x 106 m3/year. These aquifers derive from the dismemberment of the original paleogeographic units of the carbonate platform, which existed during the Miocene period. Outcrops of the Apulian carbonate aquifers, paft of the Cretaceous-Cenozoic series of the Apulian foreland, predominate in comparison to other aquifers (Figs. 2 and 3). Nevertheless, the Apulian groundwater resources do not provide sufficient regional supplies for the aqueduct systems because the basal groundwater outflows along the very extended coastline in a very diffused way, and because of the fragile equilibrium with seawater, caused by widespread and intense groundwater exploitation for irrigation purposes. According to hydrogeological characteristics observable on a large scale, the carbonate aquifers can be subdivided into three groups: i) limestone aquifers (whose average yield can be estimated to be about 3.700 x 106 m3lyear; the hydrogeological structures suggesting a mean groundwater yield ranging from 0,016 to 0,035 m3/s per k*,);
ii)
iii)
carbonate aquifers consisting of altemating limestone, limestone with chert, marly limestone and subordinately marls (whose average yield can be esti-
mated to be about 100 x 106 m3/year; the hydrogeological structures show a mean groundwater yield ranging from 0,009 to 0,015 m3/s per k*'); mainly dolomitic aquifers (whose average yield can be estimated to be about 300 x 106 m3/year; the hydrogeological structures show a mean groundwater yield ranging from 0,013 to 0,021 m3ls per k*').
The main springs of carbonate aquifers are characteristically located along the basal permeability boundaries, in contact with relatively impermeable aquifers such as those of the Miocene terrigenous lithotypes or the volcanic products or Pliocene-Quaternary marine and continental deposits. Where the PioceneQuaternary deposits have a very high permeability, these aquifers are fed by the groundwater flow coming from adjacent carbonate aquifers. The basal groundwater of coastal carbonate aquifers outflows towards the coastline. 5.2 PlrocpNe-QuernnNARy coNTINENTAL AND PoRous MARINE AQUIFERS Porous Pliocene-Quatemary aquifers, due to their importance to groundwater exploitation, were prime objectives for research, and underwent extensive studies and development during the implementation of Special Projects 26 and 29 carned out by the Cassa per il Mezzogiorno; these were supplemented by several other hydrogeological studies at a local scale, involving alluvial, coastal and intramontane plains deposits. The high importance of these aquifers is due primarily to the intensive land use of these flat areas, which always implies a strong demand of groundwater resources, especially favoured by the shallow depth of the water table. Experience gathered on these aquifers was also supported by the need to protect the groundwater resources, which are locally very vulnerable to pollution, because the protection of the thin vadose zone is generally weak. Pliocene and Quaternary aquifers consisting of terrains deposited in continental environments or which emerged after the elevation of the Apennine chain, have different, but at same time common, hydrogeological features and analogous types of groundwater flow schemes. Deposits related to very different sedimentation environments make up these aquifers: talus deposits, alluvial deposits and coastal marine deposits. These deposits give rise to continuous but heterogeneous and anisotropic aquifers, whose permeability is due primarily to porosity and rarely to permeability related to fracturing. The aforementioned hydrogeological characteristics are the result of the clastic nature of the deposits, which only rarely exhibit any grade of cementation. However, where cementation exists, it has never had a role equivalent to that of diagenesis, inducing a rock-like behaviour; hence the main form of permeability is related to porosity and only subordinately to fractures. The permeability of these aquifers is very variable and is controlled by the grain sizes distribution. Debris cones and talus slopes can generally be classified as slope deposits, which give rise to heterogeneous and anisotropic aquifers with high a grade of permeability, as is especially the case for debris cone deposits made up of uncemented pebbles and gravel. These deposits form aquifers characterised by a moderate lateral variability of their hydrogeological characteristics as a result of a less selective sedimentation process. A groundwater flow can develop in these deposits when a relatively impervious lower boundary exists, which allows percolating waters to form a saturation zone. Moreover, groundwater flow can also occur when groundwater feeding from adjacent hydrogeological structures takes place.
Alluvial and coastal deposits outcrop more diffusely in Southem Italy as compared to the other deposits belonging to this category. These deposits can be differentiated into many sedimentation environments characterised by different hydraulic energy, which are distributed over the territory by means of a decreasing energy path, starting from alluvial fans and ending with coastal plains, crossing through mountain torrents, braided rivers (occurring in piedmont sectors of rivers), and alluvial plains with meanders. All previous sedimentation environments, related to the great category of alluvial environments, are characterised by the variable energy of the hydraulic transport medium, related to the temporal variability of atmospheric precipitations, during single or consecutive hydrologic years. This implies the sedimentation of different grain sizes, ranging from cobbles to clays, with different permeability characteristics, which lie in lateral juxtaposition owing to the lateral movements of river channel. As a result of this feature, which characterises all alluvial environments, the aquifers formed by these deposits are heterogeneous and anisotropic, especially in alluvial and coastal plains, where hydrogeological properties are strongly differentiated owing to the presence of silty clayey grain sizes, ranging in relative grade of permeability from low to impervious. In these hydrogeological settings, depending on the existence of low permeability levels interbedded with aquifer deposits, the groundwater flow on a local scale is often made up of a multilayered aquifer system within which both confined and unconfined aquifers can exist. These aquifers can have differentiated piezometric heads, causing groundwater interchanges, which are oriented upward or downwards, depending on the sense of the hydraulic gradient. In many cases this groundwater flow scheme can be simplified over a large scale, because of the scarce lateral continuity of low permeability levels, which prevents an effective hydraulic isolation in multilayered aquifer systems. Indeed, on a large scale, the behaviour of these groundwater bodies can be simulated as being unitary with a common outflow. It is clear that alluvial plains groundwater, in addition to recharge from the effective rainfall, can also be recharged directly by groundwater feeding from adjacent hydrogeological structures. This situation can occur if the following conditions exist: a) the groundwater flow in the hydrogeological structures outflows toward the alluvial plain; b) the piezometric and alluvial sediment depths coffespond to the boundary between the alluvial plain and the hydrogeological structure; c) the alluvial deposits directly in contact with the hydrogeological structure are not impervious. A surf,rcial freshwater body, such as a river, or a lake, or the sea, generally represents the groundwater outflow in the alluvial aquifers. The relationships between the groundwater and the surficial freshwater bodies can be reversed, or change during the hydrologic year according to the relative change in hydraulic heads. When particular boundary conditions occur, the groundwater flow in the alluvial aquifers can outflow towards the adjacent hydrogeological structures, particularly when the latter has a groundwater outflow positioned at an altitude lower than the piezometric heads of the former. These situations can happen in Southern Italy especially when alluvial aquifers and hydrogeological carbonate aquifers are in juxtaposition. A particular case of these hydrogeological relationships is represented by the karst sinkholes and swallow holes buried under alluvial deposits, which are still hydraulically active (e.g. Solofrana river valley). Further interest in alluvial aquifers derives from the importance of their own groundwater yields, especially in the case when there exists a groundwater feeding
10
from carbonate hydrogeological structures or from surficial freshwater bodies. The latter can be artificially provoked by means of groundwater withdrawal. In a territory like that of Southern Italy, where the principal springs are tapped, hydrogeological research on alluvial aquifers could permit the identification of integrative resources in the component of the groundwater, coming from carbonate hydrogeological structures, which flow seaward through alluvial aquifers. Obviously, the use of the above mentioned groundwater resources needs the identification and the respect of the natural hydrogeological equilibrium, which controls the minimum discharge of rivers necessary for the ecosystems and the relationships between groundwater and seawater in the coastal plains (Art. 1, Law n. 36 January sth 1994). It is well known that this equilibrium can also be evaluated by means of accurate hydrologic budgets. 5.
3 Pr-rocrNr-QuarenNARy voLCANIC
AQUIFERS
Volcanic aquifers represent some of the most complex hydrogeological systems of the Southern Apennines, as a result of the variable and often contrasting hydraulic properties of volcanic terrains and to the complex geometry ofjuxtaposition contacts, as well as with other confining aquifers. In Southern Italy these aquifers result from the activity of the eruptive centres which began at the end of the Pliocene and which developed during the Pleistocene along the Tyrrhenian side of the Apennine chain (Roccamonfina, Phlegrean Fields and Somma-Vesuvius), but external to, and with different geodynamic signif,tcance (Vulture). Therefore in Southern ltaly, volcanic aquifers are synchronous with the ancient alluvial deposits, which were formed after the build-up of the Apennine chain, and interbedded or in lateral juxtaposition with the latter. Notwithstanding the hydrogeological complexity, which makes groundwater exploitation difficult, the importance of these aquifers is represented by the high economic value of the groundwater, often characterised by valuable organoleptic properties, such as CO, concentrations, among others. The limited extension of volcanic aquifers on a continental scale and their variablo properties have not favoured a great development of studies of their hydrogeological features, as had occurred for the aforementioned hydrogeological contexts. However on the basis of the work of some researchers (Devrs and DE WtESt, 1966; Menzzx,1923; StraRNS, L942; CnLtco, 1983; CusroDro, 1978) at the moment it is possible to outline the principal hydrogeological characteristics of these volcanic rocks. Owing to the alkali-potassic volcanism of Southem Italy, characterised mainly by explosive and subordinately by effusive activity, pyroclastic products predominate on the lavas. In particular, because of the relatively great volume of ignimbrite deposits, these are more hydrogeologically relevant than other pyroclastic aquifers. The Campanian Ignimbrite and Neapolitan Yellow tuff represent the principal ignimbrite deposits. Pyroclastic deposits have more uniform hydrogeological characteristics than the effusive rocks, though great variations can occur within single deposits. As a result, the groundwater flow varies significantly from zone to zone in these volcanic rocks and even though generalisations are useful, the hydrogeological variability can be locally very high. Pyroclastic products consist ofvery different grain sizes, cohesion, and fracturing and therefore different hydrogeological properties. The larger pyroclasts, represented by volcanic bombs and blocks and by scoriae and pumice fragments, usually fall within a relatively short distance from the crater rim, giving rise to high permeability agglomerates and pyroclastic breccias. The smaller dimensions pyroclasts, including lapilli, coarse and fine ash deposit further away from the crater. It
11
is known that pyroclasts are ejected by eruptive energy andlor transpofted by atmospheric currents, which induce a grain size sorting, giving rise to ash fall deposits. Altematively, when the pyroclasts result from nuées ardentes caused by the collapse of eruption clouds, ash flow deposits are formed. Lithification processes affect the ash flow deposits by welding and/or recrystallization phenomena, which can occur in different grades, resulting in the formation of tuff deposits whose
cohesion can range from completely loose to well lithified. The primary porosity of such pyroclastic deposits is inversely proportional to the lithification because the latter is the result of the partial occlusion of interclast pore space. Fracturing during cooling represents an important part of the secondary porosity, which can exist only in lithified parts of those pyroclastic deposits with a brittle behaviour. Cooling fractures generally extend vertically, perpendicular to the cooling surface, thereby assuming a typtcal columnar structure. These discontinuities are summed to the tectonic and volcanic-tectonic ones. The total porosity is generally high, up to 40oÀ + 600À, especially in cohesionless deposits. A fraction of the total porosity is not hydraulically relevant because it consists of unconnected intraclast pore space produced by magma outgassing. In volcanic rocks the capacity of the primary and secondary porosities to transfer groundwater depends on several factors. The larger the pore spaces, the higher is the interconnection grade; therefore the higher the permeability of the deposit. In ash flow deposits an increase in the lithification grade can usually be detected in the central part of the lithosomes, reflecting slower cooling conditions. Paradoxically even though in the central part of the lithosome the primary porosity is lower than in the upper and lower parts because of welding, a relatively higher grade of fracturing exists in the middle zone owing to its brittle behaviour. Consequently in the central parts of ash flow deposits the hydraulic conductivity is generally higher. The transmissivity in ash flow aquifers is variable, ranging from 6,0 x 10-5 m2ls to 2,0 x l0-7 m2is, with a mean value of 9,0 x 10-6 m2is according to results from field experiments carried out in the USA (Wruocnao and TttoRoaRsoN, 1975). Instead higher specific capacity values have been measured in tuffaceous aquifers of the Phlegrean Fields, ranging from 10-3 to 10-5 m2ls magnitude orders (Crr-rco et al., 1991; Cruco et a1.,2001), reflecting the high grade of fracturing of tuffs related to the intense volcano-tectonic activity of the Phlegrean caldera. Hydraulic characteristics of aquifers in lava flows depend on the chemical composition of the magma, on dissolved gas content and on the thickness of the deposit. Except for massive basalts, the upper part of lava flows is characterised by very high permeability; this layer can be formed by breccias, open cooling cracks and outgassing pores (particularly with acid composition magma and with high dissolved gas content). The central part of a lava flows is generally characterised by a relatively lower permeability, mainly related to cooling fractures and subordinately to outgassing porosity. Fracturing tends to increase toward the base of the flow and approximately divides the lava flow into columnar prismoids. When lava flows are in lateral contact, the interflow sector provides the higher permeability zone. According to the existence and the intensity of those factors which determine primary and secondary porosity, the hydraulic conductivity in lavas can range over a very wide interval, up to 11 orders of magnitude, ranging from 10-10 cm/s to 101 cm/s. The high permeability grade which can be attributed to lava aquifers of Southern Italy is the result of high outgassing phenomena and, as is found in stratovolcanoes, because of the isolation of lava flows by interbedding among pyroclastic deposits, favouring fracturing by cooling.
12
5.4 CeLesnrAN rGNEous AND METAMoRpI{lc
AQUIFERS
Aquifers within the igneous-metamorphic rocks of the Calabrian-Peloritan may included amongst those which make up hydrogeological sttuctures of lesser be importance to the regional aqueduct supply of Southern Italy. These kinds of aquifers are known to form complex hydrogeological systems in which a surficial porous aquifer, represented by the weathered zone, coexists and interacts with the intermediate aquifer formed by the deeper fractured rock-mass. Both the cited aquifers are limited downwards through an undefined permeability boundary by a zone of the deep rock-mass in which the fractures are closed by lithostatic pressure. Thus, the deeper part of the rock-mass acts as a relatively impervious aquifer compared to the surficial one. Regarding their importance in the regional aqueduct water supply, these igneous and metamorphic aquifers can be considered equivalent to some of the more permeable aquifers among the lithostratigraphic units of the Miocene basin and the foredeep sedimentary series. These aquifers, due to their scarce regional hydrogeological relevance have never been object of detailed studies regarding groundwater flow schemes. The studies carried out have permitted the definition of the general characteristics of the groundwater flow and the survey of the numerous springs, often with discharges of less than 0,010 m3/s. These igneous and metamorphic hydrogeological complexes form various hydrogeological structures in the Calabrian Arc, with an overall extension of about 5.900 km2. The resources of these aquifers, less important than those of the carbonate aquifers, can be considered of only local imporlance. The groundwater flow and the recharge of these aquifers is influenced primarily by the weathering grade of the rock-mass, which is known to change with depth and with the development of fracturing. The weathering profile of the Calabrian igneous and metamorphic hydrogeological complexes can be summarised as consisting of a strongly weathered surficial horizon of silty and sandy residual deposits. The weathering grade decreases progressively downwards until bedrock is reached. This typical weathering profile, recognised in other regions of the world (Acwonru, 1987), can be hydrogeologically defined as being a surficial porous aquifer overlaying a fractured aquifer which is bounded downwards by a relatively impermeable bedrock. The hydrogeological characteristics of the surficial aquifer, made up of residual deposits, depend on the grade of weathering and on the prevalent grain size class. The eluvial deposits act both as temporary groundwater reservoirs for the effective infiltration water, which subsequently percolates downward in the fractured aquifer, and as an independent surficial aquifer. Where the thickness of the cohesionless surficial deposits is only a few meters, the modulation role prevails, allowing the downward percolation of the groundwater to the fractured aquifer. Instead, where schistose rocks are dominant or the eluvial mantle is very thick (up to some tens of meters) the groundwater flow in the surficial aquifer is more important. Moreover, owing to the heterogeneity of the loose deposits, and particularly because of the presence of clayey levels, some perched water tables can exist in the surficial aquifer. This kind of groundwater circulation is well demonstrated by the numerous springs in the middle-upper part of slopes (with a discharge often less than 0,001 m3/s), emerging from the eluvial mantle; boreholes also provide evidence for the presence of perched water tables. In the fractured aquifer, below the eluvial mantle, there occurs the principal groundwater flow of the igneous-metamorphic aquifers. This transitional horizon is often some tens of meters thick and is characterised by a fracturing network related to tectonic stresses, generally with openings of less than 1 mm. The spacing and
13
the attitude of the discontinuities vary in relationship with tectonic loading and unloading to which the rock-mass has been subjected. In any case it is possible to verify that there is a higher degree of fracturing in granite rock-masses than in schists, following different rheologic behaviours. In particular, in correspondence to those faults related to the more recent tectonic phases, such as the PliocenePleistocene ones, the rock-mass shows a very thick intensely fractured zone. As observed in many zones of the world (Ln GneNo, 1954; Davrs and Ds Wmsr, 1996; SuvtvtERS, 1972), the fractures tend to close downward because of the lithostatic pressure, such that the rock-mass permeability generally decreases with depth. The consequence of the foregoing concepts is a hydrogeological model characterised by a transitional fractured aquifer bounded downwards by a relatively less permeable rock-mass. The transmissivity of the igneous and metamorphic aquifers ranges from 10-a m2ls to 10-6 m2ls. The water tables in this aquifers are generally unconfined and with high piezometric gradients (ranging from 1% to l5o ), for which outflow directions are directly or indirectly controlled by topographic conditions. In fact, the main groundwater outflows occur as springs, rarely with discharges more than 0,050 m3/s, where a favourable geomorphologic condition, often represented by an increasing downward slope angle, permits the approach of the water table to the topographic surface. The linear springs along the stream channel, evidenced by an increasing discharge along the channel (up to 0,500 m3ls), is more important evidence of groundwater outflow, particularly where the river channels cross a fault zone. Where Quaternary alluvial deposits bound the igneous-metamorphic mountains, groundwater feeding from the fractured aquifer to the porous one can occur. Evidence for this hydrogeological behaviour of the igneous-metamorphic rock-mass derive from the analysis of data related to springs and river discharges and piezometric levels collected by the Cassa per ilMezzogiorno during Special Project 26 (Calabria). The springs are mainly characterised by a small discharge (less than 0.001 m3is); only 150 springs among the 2.662 surveyed in Calabria have a discharge which ranges between 0,010 m3ls and 0,050 m3/s. These springs are located in valley bottoms or at the base of mountains. The hydrological regime of these springs, which shows a moderate excursion during the hydrologic year, implies groundwater feeding from low transmissivity aquifers and with the modulation effect induced by aquifers formed by porous eluvial mantles. In the drainage network a significant perennial flow generally exists, which can be related to groundwater feeding. The increase in stream discharge has been surveyed particularly in relation to schistose rocks outcroppings. Instead, where granites outcrop, an increase in the stream discharge occurs mainly in correspondence to the deeper valleys. These different results can be correlated respectively to the different roles performed by surficial porous aquifers in metamorphic rock-masses, and to the predominance of the groundwater flow in transitional fractured aquifers of granitic rock-masses. As already demonstrated by LB GneN» (1954) for other outcropping areas in the world, the specific capacity is controlled by the topographic position of wells. Generally, more productive wells, up to 0,010 m3/s, are located in the lower zones, often in correspondence to faults. Instead, wells dug in fractured aquifers, even though sited along the slopes or on the flat summit areas of igneous-metamorphic mountains, will have yields ranging from about 0,001 to 0,003 m3/s. In accordance with the aforementioned characteristics, the maximum values of aquifer transmissivities were found in the bottom of valleys or at the base of hills (up to 10 a m2ls).
t4
On the basis of large-scale assessments, for the Calabrian crystalline and metamorphic aquifers about the 90oÀ of the groundwater flows feed stream flows, whereas the remaining l0oÀ feeds springs and alluvial deposits which surround the crystalline-metamorphic mountains (BrsoN et al., 1995). Detailed evaluations of the Serre massif yield, where both granites and schistose rocks outcrop, have evidenced an average yield ranging from 0,004 to 0,007 m3/s per km2 and a mean annual recharge ranging from about l0oÀ to 20% of the amount precipitated. The latter values could be higher than those reported in the hydrogeological literature for the same lithologies (SurHIle and Rao, 1983; AruAvaLr, 1985; MuRauonARAN et al., 1988; ArrpN and Davt»soN, 1982; TurrRv, 1988; HousroN, 1988; Issln and Grrao,1982). The reason for such a difference can be attributed to the arid and semiarid climate of the areas of principal outcrops of the crystalline-metamorphic rocks, which are subjected to a high evapotranspiration rate. In contrast, in Calabria there exist favourable conditions for aquifer recharge due to the latitude and to the particular morphology of the territory. Moreover, among other favourable factors, one can take into consideration the high annual amount of atmospheric precipitations (up to about 2.000 mm/year on average), the relatively low temperatures (with a mean value ranging from 8 oC to 15 oC), the presence of flat summit areas and the almost continuous eluvial mantle. 5.5 Men.TNE BASIN SEDIMENTARY
SERIES AQUIFERS
In Southern Italy, in addition to the principal aquifers described in previous paragraphs, there also exist other aquifers of minor hydrogeological relevance, made up by lithostratigraphic units formed by the sedimentary series of marine basins and by the Miocene foredeep terrigenous series. Such lithostratigraphic units give rise to hydrogeological complexes with a common type of prevalent permeability, usually due both to fracturing and to porosity, resulting in up to a medium relative permeability grade where the pelitic component, normally diffused in these sedimentary series, is scarce. These hydrogeological complexes give rise to the smaller mountains and hills of the Southern Apennines, forming hydrogeological structures satisfactory only for the local water supply of rural towns. The structures which are made up of these hydrogeological complexes, because of their scarce groundwater yield resulting from the moderate permeability of the rock-mass, generate scattered springs, with discharges rarely more than few tens of litres per second. The sedimentary series of the marine basin outcropping in Southern Italy can be related to, pre-existing the Miocene orogenic phases, paleogeographic units of Sicilide, Liguride, Lagonegro, Molisan and East Gargano basins and of Irpine and Cilento Miocene foredeep basins (BoNanot et a1., 1988). The lithostratigraphic units related to this sedimentary series contain aquifers with a generally negligible relevance to regional aqueduct systems. Therefore few studies have been carried out on these aquifers, by which it is only possible to delineate the general groundwater flow scheme. The typical lithologic heterogeneity, characterised by the coexistence of pelitic and massive units of calcareous andior siliciclastic arenites, results in a relative permeability grade, generally variable from low to impervious, and a mixed type of permeability, due both to the fracturing and to the porosity of pelitic units. The complex structural setting (Esu, 1977), variable because of the rhythmic interbedding of the aforementioned lithologic units, with their diffuse occuffence of impervious argillitic units in the rock-mass, contributes to a scarce permeability. t5
Because of the peculiar hydrogeological characteristics, the general permeabi-
lity of the rock-mass is relatively higher in surficial zones, where the grades of weathering and fracturing are higher. Moreover, the presence of eluvial and colluvial deposits, often with a moderately higher permeability, permits the establishment of a shallow groundwater flow in the surficial zone. Such groundwater circulation occurs often with discontinuous water tables, whose piezometric profiles agree well with the topographic morphology. This approximate coincidence induces, as in the Calabrian crystalline mountains, a similarity between morphological and groundwater divides, with a groundwater outflow generally oriented towards valley bottoms and springs positioned on the slopes. The springs are numerous and mostly characterised by low discharges, which rarely exceed a few litres per second. The global flow, due to the effective precipitation, or to the amount in excess of evapotranspiration, occurs mostly as runoff and subordinately as actual infiltration. Studies on the hydrogeological characterisation ofthese aquifer are scarce and generally based on the analysis of the base flow, separated from the fluvial hydrograms (BanNrs, 1939), recorded by discharge gauges located at the outlets of some sample basins (Crr-rco et al. 1992; Consr et al., 1999). From these studies it was possible to make an evaluation of a potential infiltration coefficient (C.I.P.) lower than 20oA for the lithostratigraphic units formed by arenaceous-pelitic and calcarenite-pelitic terrains. However, this value could be lower for argillitic rockMASSES.
In the sedimentary basin series, the arenaceous-conglomeratic units, related to the younger units of the Cilento Group (BoNanor et al., 1988) and to some members of the Irpine units, differ from the previously described hydrogeological behaviour. In these parts of the sedimentary basin series, the presence of rocks with thick strata and the negligible presence of pelitic interbeddings generally induce a medium relative permeability grade in the rock-mass. Therefore in these aquifers the actual infiltration is higher and the groundwater flow is deeper; moreover it has an outflow less influenced by the external morphology but more conditioned by the stratigraphic and the structural settings (Cascmllo et al., 1995; Cruco et al., 1993). In the marine basin sedimentary series, the Formation of Limestone with Chert, belonging to the Lagonegro Units, can be also distinguished, in which, the prevalence of calcareous units on the argillitic ones, results in a medium grade of relative permeability to the rock-mass by fracturing, and allows an active groundwater flow.
6. SELECTED BIBLIOGRAPHY Acwotrs R. I. (1987) - The developement of oystalline basement aquifers in a tropical environntent. Quaterly Joumal of Engineering Geology, 20, p. 265-272. ArrpN A. D. and D,qvrosoN V/. A. (1982) - Review of groundwater resources in fractured rocks in Western Australia. Proc. of the conference "Groundwater in fractured rock", Camberra, Aug. 3lSep. 3. AWRC Conf. Ser. 5: p. 1-12. Ar-r-sn L., Br,NNer T., LrnrR J.H., Pprry R.J. and Hacrsrr G. (1987) - DRASTIC: I Stardadized System for Evaluating Ground Water Pollution Potential Using Hydrogeological Settings. EPN 60012-85/0 1 8, Washington D.C.
Arnavam R. N. (1985) - l{uclear tracer techniques for measurement of natural recharge in hard rock terrains. In: Proc. International workshop on rural hydrogeology & hydraulics in fissured basement zones. Dept. Earth Sciences, Univ. of Roorkee, India: p. 71-80. BanNr,s B.S. (1939) - Structure of disharge recession cun)es. Trans. Amer. Geophys. Union, vol. 20.
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Crrrco F. (2000) - Analysis of karstic phenomena and deJìnition of management criteria of the Biferno springs hydrogeological basin. Reporl W08, Karst Water research program. Crr-rco F., Esposrro L. and MaNcuso M. (2001) - Complessità idrodinamica e idrochimica dell'area urbana di Napoli; scenari interpretativi. Geologia Tecnica e Ambientale 2, p. 35-54. CBrrco P. (1978) - Schema idrogeologico dell'Appennino carbonatico centro-meridionale. Mem. e Note Ist. Geol. Appl. Napoli, 14. Ctr-rco P. (1983) - Idrogeologia dei massicci carbonatici, delle piane quaternarie e delle aree vulcaniche dell'Italia centro-meridionale (Marche Campania). Quademi CASMEZ, 412, p. 225.
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(1988) - Prospezioni idrogeologiche. 2, p.528, Liguori Editore, Naples. CEr-rco P., De INNocENrrs M., DE Vrra P. and Var-r-anro A. (1992) - Caratteristiche idrogeologiche del bacino del fiume Alento (Campania) - Geologica Romana vo1. 30, p. 699-707.
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Crr-rco P., Dn, Vrra and Arom A. (1993) - Caratterizzazione idrogeologica della Formazione di Monte Sacro (Cilento - Campania meridionale). GeologiaApplicata e ldrogeologia, vol. XXVIII, pp.243-252.
Cruco P., Dp Vna P., Nxz,q.o F., SreNzroNp D. and VeLLaRto A. (1991) - Schema idrogeologico e idrogeochimico dei Campi Flegrei (l'lA). Proceedings of I't National Congress of Young Researcher in Engineering Geology and Hydrogeology. Gargnano (BS) 22d ard 23'd October 1991. University of Milan. Suppl. 93, p.281-296. Crvrra M. (1912) - Schematizzazione idrogeologica delle sorgenti normali e delle relative opere di captazione. Mem. e Note Ist. Geol. Appl. Napoli,12, p l-34. CIvtre M. (1973) - Proposte operative per la legenda delle carte idrogeologiche. Boll. Soc. Natur., Napoli, 82. Ctvtre M. (1975) - Idrogeologia. In: Geologia Tecnica, ISEDI, p.179-231. CoRu I., Dr Vrra P. and VarleRlo A. (2000) - Caratterizzazione idrogeologica per I'analisi morfoevolutiva delle formazioni strutturalmente complesse della media e bassa valle del fiume Biferno (Molise) - Atti V Convegno Nazionale dei Giovani Ricercatori in Geologia Applicata, 8-11 ottobre 1996, Cagliari - Facoltà di Ingegneria, p. 231-239.
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D'ARcsNro B. (1988) - L'Appennino campano-lucano. Vecchi e nuovi modelli geologici tra gli anni sessanta e gli inizi degli anni ottanta. Relations to the 74th Congress of the Italian Geological Society, Sorrento I 3- 1 7 September. Devrs S. N. and Dr Wmsr R. J. M. (1966) - Hydrogeologt. John Wiley & Sons, New York, 463.
Esu F. (1977) - Behaviour oJ'slopes in structurally complex formations. Geothecnics of Structurally Complex Formations, Capri 2, A.G.I. Roma.
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Gruq.sst D. (1974) - Il carsismo della Murgia (Puglia) e sua influenza sull'idrogeologia della regione. Geologia Applicata e ldrogeologia, 9, Bari.
HousroN J. (1988) - Rainfall-runolf-recharge relationships in the basement rocks of Zimbabwe. 81 1990, p. 27 I -283.
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INrEtNarroNaL SUBCoMMISSIoN oN Stnetrcn-A.pHrc CLASSrFrcArroN (ISSC) (1976).In: Hedberg, H. D., ed., Intemational Stratigraphic Guide, New York, John Wiley and Sons, p. 200. IssanA. and Gtlen D. (1982) - Groundwaterflow systems in the arid crystalline province of southern Sinai. Hydrological Sciences Joumal, 27, p. 309-325. Jacosaccl A. and PenNo U. (1970) - Geological map of ltaly l:100.000. Sheet no 220. Verbicaro. Istituto Poligrafico e Zecca dello Stato. JoRcpNssN D. G. and RoseNsnrrN J. S. (1987) - Naming aquifers. EOS Transaction of the American Geophisical Union, 68, no. 15, p.210-211. LRNsv R.L. and DevnsoN C.R. (1986) - Aquifer-nomenclature guideline. U.S. Geological Survey Open-File Report 86-534, p. 46.
Ls GnaNo H. E. (1954) - Geology and ground water in the Statesville area, North Carolina. North Carolina Dept. Conservation Developement, Div. Mineral Resources Bull. 68. LEoNamt P. (1968) - Geologic map of ltaly 1:100.000. Sheet no 213. Maruggio. Istituto Poligrafico e Zecca dello Stato. LsoNanot P. (1968) - Geologic map of ltaly 1:100.000. Sheet no 215. Otranto. Istituto Poligrafico e Zecca dello Stato. LEoNanni P. and Rossr D. (1968) - Geologic map of ltaly 1:100.000. Sheet no 204. Lecce. Istituto Poligrafico e Zecca dello Stato. LeoNe.Ror P. and Rossr D. (1968) - Geologic map of ltaly 1:100.000. Sheet no 214. Gallipoli. Istituto Poligrafico eZecca dello Stato. LroNe«or P. and Rossr D. (1970) - Geologic map of ltaly 1:100.000, Sheet no 203 Brindisi. Istituto Poligrafico e Zecca dello Stato. LoHlreN S.W. (1972) - DeJinitions of selected ground-water terms. Revisions and conceptual
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Geologic map of haly. Sheet no 202. Taranto.Istituto Poligrafico
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dello Stato. Mexpy G.B. (1964) - Hydrostratigraphic Units. Journal of Hydrology, 2, p. 124-129. MErNzsR O.E. (1923) - The occunence of groundwater in the United States, with a discussion of principles. U.S. Geological Survey Water-Supply Paper 489, p. 321. MuRar-roHanaN D., Atuevels R.N. and Munu C. S. (1988) - Comparison of recharge estimafrom injected tritium technique and regional hydrological modelling in the case of a granitic basin in semi-arid India. In: Estimation of Natural Groundwater Recharge (NAIO Advance Science Institute Series, C; Mathematics and Physical Science, 222)1. Simmers (ed.): pp. 195-220. Owr,N D. E. (1987) - Commentary; Usage of stratigraphic terminologlt in papers, illustrations, and talks. Journal of Sedimentary Petrology, 7,2, p. 363-372. tes
SrsaRNs H.T. (1942) - Hydrology of volcanic terrain. In: Meinzer O. E., ed., Physics of the earth; Part 9, Hydrology. McGraw-Hill, New York.
Surnlre B. S. and Rao A. A. (1983) - Envinromental tritium and radiocarbon studies in the India. Jounal ofHydrology, 60, p. 185-196. Surrllrr,ns W. K. (1972) - Specific capacities of wells in oystalline rocÀs. Groundwater,6, p.37-47. Vedavati River basin, Karnataka and Andra Pradesh,
Tnrenv D. (1988) - Analysis of long duration piezometric records from Burkina Faso used to determine aquifer recharge. In: Estimation of Natural Groundwater Recharge (NATO Advance Science Institute Series, C: Mathematics and Physical science, 222)I. Simmers (ed.): p. 477-489.
18
UNrre» NauoNs EoucerroNa.r, ScrrNrIrIc aN» Culruner- ORcaNzArtoN (LINESCO), Wozu-o
Mpre,onoroctcar OnclNIZArIoN (WMO) (1977) - Preparation of ground-water maps, in Hydrological maps. Louvain, International Association of Hydrological Sciences, Studies and Reports in Hydrology 20, p. 135-192. V.V.A.A. (Various years) - Geological map of Calabria (167 sheets 1:25.000 scale)
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Cassa per
il Mezzogiomo, Coordination of the National Geological Service. 'WrNocnq.o I. J. and TuoRoansoN V/. (1975) - Hydrogeologic and hydrochemical framework, south- central Nevada-California, *-ith the special reference to the Nevada Test ,S,/e. U.S. Geological Suwey Professional Paper 7l2C, p. 126.
19
Clipping
lron the "Hydrogeologico/ Mop of Southern ltoly" (Mop l, Souifiern Apennine - Gorsoao)
