Document Actions

ijege-15_01-tarragoni-et-alii.pdf

background image
5
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
DOI: 10.4408/IJEGE.2015-01.O-01
C
LAUDIA
TARRAGONI
(*)
, P
IERO
BELLOTTI
(**)
& L
INA
DAVOLI
(**,***)
(*)
Geologist and AIGEO Member - Viale Eritrea 91, 00199 Rome, Italy - Email: claudia.tarragoni@libero.it
(**)
AIGEO Member - Via Mare Glaciale Artico 51 - 00122 Rome, Italy
(***)
Sapienza University of Rome, Department of Earth Science - P.le A. Moro 5, 00185 Rome, Italy - Email: lina.davoli@uniroma1.it
NATURAL AND ANTHROPOGENIC FORCING DURING THE LAST TWO CENTURIES
IN THE OMBRONE DELTA (SOUTHERN TUSCANY - CENTRAL ITALY)
EXTENTED ABSTRACT
Il bacino del Mar Mediterraneo presenta numerosi delta che si differenziano per forma e dimensione, ma che hanno in comune
un’evoluzione in ambiente microtidale. I grandi fi umi, come il Nilo, il Rodano, l’Ebro o il Po sono caratterizzati da foci deltizie che sono
il risultato di una complessa interazione tra la dinamica fl uviale e l’azione del moto ondoso; i fi umi minori (come il Tevere, l’Ombrone
ecc.) hanno, invece, un tipico delta a dominio ondoso.
In Italia, l’assetto morfologico e topografi co del territorio e la conformazione costiera favoriscono la presenza di numerosi delta a do-
minio ondoso che, proprio per la loro morfologia subpianeggiante, sono stati fortemente antropizzati tanto nel passato quanto nel presente.
L’intensa urbanizzazione di queste aree va considerata sotto un duplice aspetto: da un lato le strutture insediative hanno nascosto
l’assetto morfologico originario e, quindi, ne impediscono la ricostruzione morfoevolutiva di dettaglio. Altro aspetto riguarda la
ricostruzione morfoevolutiva di queste aree: essa costituisce uno strumento fondamentale per l’individuazione delle zone a più ele-
vata vulnerabilità da erosione costiera, fenomeno quest’ultimo estremamente diffuso e cospicuo. In quest’ottica lo studio dei sistemi
deltizi minori, come quello dell’Ombrone, riveste un’importanza non solo locale, ma anche esportabile a livello più regionale del
bacino del Mediterraneo.
Questo lavoro costituisce non solo un aggiornamento, ma anche un ampliamento di precedenti studi a carattere geomorfologico ed
evolutivo condotti sul delta del F. Ombrone (Italia centrale - Toscana meridionale).
L’area di studio, sita nella piana di Grosseto, è compresa tra la propaggine settentrionale dei Monti dell’Uccellina a Sud e il
canale San Rocco a Nord. Le ali del delta presentano morfotipi diversi, in particolare l’assetto dei cordoni dunari è sensibilmente
differente nelle due ali del delta: l’ala settentrionale ha cordoni dunari ben delineati (con quote che raggiungono mediamente i 4-5
metri) e presenta due piccoli bacini lacustri (la cui profondità media è di circa 4 m) disposti uno in una depressione interdunare
(Chiaro Grande) e l’altro trasversale alla linea di riva (Chiari del Porciatti); l’ala meridionale presenta una morfologia più pianeg-
giante con cordoni dunari decisamente meno rilevati, depressioni interdunari mal defi nite e poco profonde e una mancanza di specchi
d’acqua signifi cativi.
Gli studi hanno riguardato diversi aspetti: variazioni delle linee di rive, confronto tra morfologie emerse e sommerse, comparazione di
cartografi a storica, analisi del moto ondoso.
Le variazioni della linea di riva dal MedioEvo, con un maggiore dettaglio per gli ultimi 200 anni, ciò per defi nire le principali fasi
di progradazione ed erosione del delta; con un’analisi di dettaglio delle ultime decadi sono stati calcolati e comparati i tassi di erosione/
accrescimento della parte apicale del delta. In ultima analisi sono state quindi ipotizzate le forzanti naturali e/o antropiche responsabili
dell’assetto attuale dell’area.
Il confronto della morfologia dei fondali del Chiaro Grande, già ricostruita in un precedente lavoro, con la morfologia dei fondali
antistanti l’apice deltizio (1977, dati dell’IIM; 2010, nuovi dati) e del DEM del delta sommerso con le fotoaeree dell’apice deltizio (volo
ALISUD, 1995), ha permesso di evidenziare analogie che confermerebbero l’ipotesi secondo cui il Chiaro Grande si sarebbe formato
a seguito della chiusura di un braccio di mare; tale ipotesi troverebbe ulteriore conferma nelle forme che di producono stagionalmente
e che sono state osservate più volte: spit, barre sommerse e piccoli specchi d’acqua nella spiaggia emersa.
La comparazione della cartografi a storica (1823, 1832, 1851, 1871, 1883 - Archivio di Stato) con le immagini da satellite, unitamente
a dati morfobatimetrici, ha permesso di defi nire con certezza che i chiari non possono essere considerati forme relitte del lago costiero
riportato nella cartografi a storica, in quanto questo lago occupava una posizione più interna.
L’analisi del moto ondoso ha permesso di defi nire la direzione dell’ondazione prevalente e di come questa contribuisca all’erosione
asimmetrica del delta.
background image
C. TARRAGONI, P. BELLOTTI & L. DAVOLI
6
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
ABSTRACT
This study describes advances in understanding of the re-
cent evolution of the Ombrone River delta. Several aspects have
been studied and updated: the stages of progradation and retreat
of the shoreline from the Middle Ages, with particular reference
to the last 200 years, have been reconstructed and the natural
and/or human forcing responsible for the area’s evolution have
been hypothesized.
The processes that led to the formation and evolution of
some small coastal lakes and the more recent evolution of the
shoreline are defi ned. Monitoring of shoreline variations in the
Ombrone Delta apex has been achieved by comparing aerial
photos acquired in 1995, 1998, 2004, 2006 and 2010. The pro-
gressive landward migration of the shoreline has resulted in a
realignment of the coast. Comparison with older erosion and
progradation rates shows decreasing erosion rates along the
delta apex with time: the erosion rate of the northern wing has
reached peaks of around 14 m/yr (2004-2006), and then fallen
to 4.5 m/yr in the latest period (2006-2010).
The Ombrone River delta is characterized by the presence
of beach ridges, ponds and, in the past, of a coastal lake. Mor-
pho-bathymetric analysis and comparison with historical maps
shows that during the XIX century, the historical lake preserved
its geometry; only in the 1883 map seaward side presents an
irregular geometry, while in the 1929 map the ponds have been
represented for the fi rst time and are located seaward with re-
spect to the XIX century beach ridge.
Comparing morpho-bathymetric data of Chiaro Grande pond
and submerged apical mouth, this study confi rmed the hypoth-
esis about Chiaro Grande pond genesis in which its formation
is based on the closure of a narrow sea stretch consequent to the
emergence of a bar. The independence between the genesis of
ponds and lake evolution, highlighting the importance of mouth
bar growth as a recurrent mechanism for confi ning narrow sea
stretches.
The orientation of morphological features and the prevailing
wave climate suggest a sediment transport from south to north.
K
EY
WORD
s: Ombrone River Delta, shoreline evolution, ponds, historical
maps, Grosseto plain; Central Italy (UTM 32T wgs84 top left 662237E,
4730755N; bottom right 669373E, 4722606N)
INTRODUCTION
The Mediterranean coasts present several deltas character-
ized by different shapes and sizes but all evolved in a typical
microtidal regime. The largest Mediterranean rivers (e.g. Nile,
Rhone, Ebro and Po) develop deltas with a complex fl uvial-wave
interaction (S
TANLEY
et alii, 2008; S
TANLEY
& W
ARNE
, 1993;
G
ENSOUS
, 1993; A
RNAUD
-F
ASSETTA
et alii, 2005; S
OMOZA
et alii,
1998; D
IAZ
et alii, 1990; B
ONDESAN
et alii, 1995; C
ORREGGIARI
et
alii, 2005), while minor and abundant Mediterranean deltas (e.g.
Tiber, Ombrone, etc.) show the typical shape of a wave domi-
nated delta (G
ALLOWAY
, 1975). Small fl uvial-dominated deltas
develop only in locally well protected areas, as for instance, the
Isonzo River in Trieste Gulf (Italy), and the Thyamis River in
Sayada Bay (Greece).
The Holocene evolution of the main Italian deltas is widely
discussed by M
ARINELLI
(1926), D
ELLA
R
OCCA
et alii (1987), F
IRPO
et alii (1992), B
ELLOTTI
et alii (1994, 2003 and 2004), R
OMANO
et alii (1994), B
ELLOTTI
(2000), K
UKAVICIC
& P
RANZINI
(2003),
C
ORREGGIARI
et alii (2005), B
RAMBATI
(2011), B
ELLOTTI
et alii
(2012), F
ERRARI
et alii (2013), D
I
B
ELLA
et alii (2014) and S
AC
-
CHI
et alii (2014). Due to the Italian orographic setting, several
wave dominated deltas present cuspidate or arched confi guration.
The development of these deltas started after the 6 ka high-stand
culmination (A
MOROSI
et alii, 2012; B
ELLOTTI
2000; L
AMBECK
et
alii, 2004, 2011; M
ILLI
et alii, 2013; S
ACCHI
et alii, 2014), and has
signifi cantly progressed in the last 3 ka, during which prograda-
tional and erosional phases have alternated under the control of
climate, geological and anthropogenic processes. In many delta
areas the intense urbanization (as, for instance, Arno, Centa, Ti-
ber and Volturno deltas) has overprinted the primary morphologi-
cal features, thereby hampering the detailed identifi cation of the
morpho-sedimentary processes driving their evolution.
The Ombrone Delta is a wave-dominated delta located with-
in the Grosseto plain in Southern Tuscany (Fig. 1). It is one of the
main deltas on the Tyrrhenian Sea coast, which include the Arno
River Delta (130 km to NW) and the Tiber River Delta (140 km
to SE), altogether termed the “Tuscany-Latium delta system
(A
LESSANDRO
et alii, 1990). In the past, the Ombrone Delta was
one of the most cuspate deltas of Italy (B
ELLOTTI
, 2000; C
HIOCCI
et alii, 2001; B
ELLOTTI
et alii, 2012); nowadays it has a gentle
planform due to strong erosion of the apex. Several dune/beach
ridges characterize the delta plain whereas, in the northern apex,
small internal water bodies, i.e. ponds locally named “chiari”,
are present: the ponds, intra-ridge and inter-ridge, interrupt the
transverse continuity of beach ridges.
Nevertheless, it is one of the few deltas conserving natural
features (as part of it falls within a protected area), thereby pro-
viding an exceptional opportunity to study the morphological
evolution of a Mediterranean wave dominated delta.
The Ombrone Delta shows marked morphological differ-
ences between the southern and northern wings, especially as re-
garding beach ridges. Continuous beach ridges, smoothly bended
toward the river mouth, are present in the northern wing, as well
as sand ridges that are separated by the chiari (Fig. 2). The latter
sometimes show a branched geometry and cut across the beach
ridges (A in Fig. 2); in other cases they are elongated, with mi-
nor branches, and slightly transverse to sub-parallel to the beach
ridges (B and C in Fig. 2).
background image
NATURAL AND ANTHROPOGENIC FORCING DURING THE LAST TWO CENTURIES
IN THE OMBRONE DELTA (SOUTHERN TUSCANY - CENTRAL ITALY)
7
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
The southern wing is characterized by beach ridges abruptly
bending to WSW and, near the mouth, sand ridges separated by
smaller and narrow depressions.
The aim in this paper is to investigate the evolution of the
Ombrone Delta apex during the last 2 centuries, focusing on the
morpho-sedimentary processes and driving factors, with particu-
lar attention to those controlling the development of submerged
sand bars, chiari, shorelines and beach ridges. Based on historical
maps, aerial photos of the area and bathymetric data, we defi ne
also investigate short-term variations, including the disappear-
ance of a coastal lake reported in historical maps until 1883 and
hereafter termed “historical lake”.
METHODS AND MATERIALS
Morphological analysis of the inner delta front and plain has
been carried out using the following bathymetric data: single
beam echo-sounding maps from IIM (I
STITUTO
I
DROGRAFICO
DELLA
M
ARINA
, 1977), bathymetric and topographic profi les perpendicu-
lar to the shoreline (P
RANZINI
, personal comunication) and newly
acquired profi les (J
UNE
, 2010).
Comparing the evolution of the historical lake, the existence
of which is documented up to 1883, and the genesis of the ponds,
fi rst recorded in a 1929 topographical map, is based on the analy-
sis of historical maps of 1823, 1832, 1851, 1871, 1883 (A
RCHIVIO
DI
S
TATO
) and topographic maps of 1929 and 1985 (IGM - I
STI
-
TUTO
G
EOGRAFICO
M
ILITARE
). Three historical maps (1823, 1832
Fig. 1 - Location of the study area (A)
and close-up of the Grosseto
plain and Ombrone delta (B)
Fig. 2 - View of the study area in 1998.
A: Chiaro del Porciatti ponds;
B: Chiaro Grande pond; C:
most recent pond; D: spit and
submerged part of a bar extend-
ing northward from the delta
apex; E: smaller spit on the
southern wing of the delta apex
(
http://www.bing.com/maps/.
June, 1998. October, 2010)
background image
C. TARRAGONI, P. BELLOTTI & L. DAVOLI
8
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
and 1883) of the Ombrone delta were reduced to the same scale,
softly distorted, made partially transparent and superimposed on
a modern image from Google Earth of the same area for com-
parison using fi xed control points. The stretching mean errors
value (less than 5 m) has been assumed acceptable. These maps
have been imported in Google Earth for digitization of the shore-
line, the historical lake and the chiari. The evolution of ancient
shorelines has been defi ned based on the geometric relationship
between beach ridges, some of which could be dated by means of
archaeological data, ancient maps and chronicles.
The reconstruction of the recent shoreline change has been
obtained by the comparison of images from different years; we
have used air photographs (ALISUD fl ight, 1995) and available
satellite images (http://maps.live.it, 1998; Google Earth, 2004
and http://www.visual.paginegialle.it, 2006; http://it.bing.com,
2010). Images from different websites (23 images from http://
www.visual.paginegialle.it
; 14 images from http://maps.live.it
and 41 images from http://it.bing.com) and air photographs (AL-
ISUD fl ight, 1995) have been geo-referenced with the software
Global Mapper, which was also used for digitizing the shorelines.
Also previous shoreline reconstructions (B
ELLOTTI
et alii,
1999a,b) have been taken into account for comparison aimed at
detecting signifi cant changes in shoreline dynamics (Fig. 5).
RESULTS
LAKE - PONDS
The historical maps (1823, 1832, 1851 and 1871) show a
more cuspate shape of the delta and the presence of a lake in the
northern wing that presents, always, a regular. Linear seaward
side; only in the 1883 map is the seaward side of the lake shown
as irregular (Fig. 3C). From the comparison of these maps, the
position of the lake is always landward of the ponds (which are
fi rst represented in the 1929 map) and the XIX century beach
ridge (I
NNOCENTI
& P
RANZINI
, 1993).
The single beam echo-sounding survey was carried out in
the Chiaro Grande pond and the adjoining landward depressed
and submerged area (hereafter called “depression”) in May 2009.
The data acquired was used to produce a DEM (3x3 m) of the
morphobathymetry of the Chiaro Grande pond (T
ARRAGONI
et alii,
2009, 2011; AA.VV., 2010), whereas for the rear lake no DEM
has been created. These two areas, connected by a narrow breach
in the XIX century beach ridge, have the same orientation (N-
Fig. 3 - A, B, C: Close-up of the 1823 (left), 1832 (centre) and 1883 (right) Maps; in the former, the lake has a straight seaward bank, while in the latter,
the seaward side of the lake is strongly irregular. D: location of depression in the Ombrone River mouth. E: relative position of Chiaro Grande
pond and depression (1823). F: Location of bathymetric profi les acquired in 2010
background image
NATURAL AND ANTHROPOGENIC FORCING DURING THE LAST TWO CENTURIES
IN THE OMBRONE DELTA (SOUTHERN TUSCANY - CENTRAL ITALY)
9
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
S) but show marked differences. The pond, characterized by a
branched geometry (Fig. 4), has a mean depth of 3.5 m, with
two main axially elongated depressions of 4 and 4.5 m depth.
The pond occupies an inter-ridge position separating an exter-
nal ridge, located close to the present shoreline, from an internal,
landward-sited, ridge. The seaward side of the pond is at the toe
of the external ridge lee face which shows a higher slope than the
landward side. This grades laterally into the stoss side of the in-
ternal ridge (Fig. 4). Sandy sediments characterize the fl oor of the
pond. The landward depression is characterized by an extremely
regular bathymetry and was found to be submerged under a thin
water table of about 30-40 cm during the wet season; its fl at fl oor
is characterized by silty-clay sediments.
A second survey was carried out in the two Chiaro del Por-
ciatti ponds in June 2009. The presence of copious vegetation
(up to water surface) hampered the acquisition of high resolu-
tion data, therefore no DEM has been created, but some observa-
tions have been done: the bathymetry is similar to that of Chiaro
Grande pond (mean depth about 4 m) but the general morphology
is different (there is no asymmetry in shape and there are several
branches); no samples were taken because of vegetation.
SHORELINE VARIATIONS
LONG TERM SHORELINE VARIATIONS
The trend of the ancient shorelines is revealed by the presence
of the beach ridges and analysis of their geometrical relation-
ships, allows the identifi cation of former prograding and erosive
phases. From this point of view, some authors (B
ELLOTTI
, 2000;
K
UKAVICIC
& P
RANZINI
, 2003) describe different patterns related
to river input and longshore transport at the river mouth. On the
basis of the beach ridge geometric patterns proposed (K
UKAVICIC
& P
RANZINI
, 2003) the following evolutionary phases (from 1283,
date of construction of Torre Trappola) have been recognized
(Fig. 5):
Phase 1. Progradation stage (post Upper Middle age - “Dark
Ages”) characterized by beach ridges organized according
to converging geometric pattern (type B and C, in northern
wing, and C and D in southern one).
Phase 2. Erosion stage characterized by the truncation of pro-
truding ridges and the emplacement of straighter ones (type
G and H).
Phase 3. Progradation stage with complex beach ridge pattern.
Both wings show converging geometric patterns (type C and
D in northern and D in southern) but also local truncation of
beach ridges (type H).
Phase 4. Erosion stage with truncation of beach ridges in nor-
thern wing while in southern the truncation is less clear (type
G). Probably, this phase is related to the construction of the
“La Steccaia” dam (1875-1879; http://www.wadi.unifi .it/
grosseto_plain_ital.pdf
) and the great drainage works that
occurred between 1830 and the beginning of the XX century.
Phase 5. Progradation stage in which the northern wing shows a
converging geometric pattern (type C and D) while the sou-
thern one presents sub parallel beach ridges (type D). Modern
ponds (Chiaro Grande and Chiaro del Porciatti), located in
the beach ridges of the northern wing, are represented for the
Fig. 4 - DEM of the Chiaro Grande pond (left) showing the elongated shape, the deeper depression and the shallower branching (maximum depth of 70
cm). The bathymetric map (right, above) shows the distribution and shape of the deepest depressions. Two examples (A-A’ and B-B’) of profi les
that show transversally the asymmetric shape of Chiaro Grande; seaward bank to the left)
background image
C. TARRAGONI, P. BELLOTTI & L. DAVOLI
10
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
fi rst time in the 1929 map: this suggests that the progradation
phase started around the end of XIX century when the main
drainage works were fi nished.
Phase 6. Erosion stage with truncation of beach ridges (type G),
probably started around the second half of the XX century.
RECENT SHORELINE VARIATIONS
Five shoreline positions have been compared so as to investi-
gate the most recent evolution trend of the apex of the Ombrone
mouth (between 1995 and 2010): alternating periods of coastal
erosion and progradation have been identifi ed (Fig.6 and Table
1). The study area has been divided in 4 sectors from North to
South (Fig. 1B; a - From S. Rocco Canal to Chiaro del Porciatti
ponds; b - From Chiaro del Porciatti ponds to Ombrone River
mouth; c - From Ombrone River mouth to Marina di Alberese; d
- From Marina di Alberese to Colle LungoTower). For each sector
erosion/progradation rates have been calculated.
From 1973 to 1995 (B
ELLOTTI
et alii, 1999a, b), both wings
Fig. 5 - Ombrone River delta: main beach ridges and shoreline positions in different erosion phases
Fig. 6 - View of the delta apex in 2010. The 1995 (white lines), 1998 (dash light grey lines) and 2006 (dark grey lines) shorelines are represented. The
shoreline of 2004, being very similar to that one of 1998, has not been represented in order to make the fi gure clearer. Along the line A the retreat
is about 85 m and along B it is about 125 m. On the right, the hard structures have been indicated by white arrows
background image
NATURAL AND ANTHROPOGENIC FORCING DURING THE LAST TWO CENTURIES
IN THE OMBRONE DELTA (SOUTHERN TUSCANY - CENTRAL ITALY)
11
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
show an erosional trend (sectors B and C) but in the northern
wing the erosion rate is more marked (Table 1); along A and D
sectors a very low progradation rate is evident. In the next time-
interval there is strong erosion in the C sector (-8 m/yr), while
the northern wing is strongly prograding (5 m/yr). The high pro-
gradation rates are concomitant with marked erosion of the apex,
likely cannibalizing the sediment there eroded. From 1998 to
2004, the northern wing (B) experienced erosion and the sector
A showed a lower progradation rate, while in the southern wing
the erosion rate of sector C was high (-4 m/yr) and in the last area
no signifi cant changes were observed. Comparing shorelines of
2004 and 2006, the entire northern wing experienced erosion
particularly in B (-14 m/yr); the southern wing shows variations
comparable with the expected seasonal variations; therefore the
shoreline may be assumed as stable. This is supported by the
presence of a stable barrier at the apex (C). In the last time inter-
val (2006-2010), the northern wing continues to be eroded but at
a lower rate near the apex (B), while the northernmost sector (A)
and the southern wing appear unchanged.
From the images (1995 and 1998) it is possible to view the
presence of emerged and submerged bars from south to north.
These bars can be quite elongated, extending from the south-
ern wing to the northern (Fig. 2, 5, 6, and 8). At the apex, the
coast north of the mouth has retreated some 230 meters in the
last 15 years (Fig. 6).
The data acquired from the IIM (1977) allowed production of a
DEM (T
ARRAGONI
et alii, 2011) of the submerged inner delta front
(Fig. 7A). From the observation of DEM (Fig. 7A), bathymetric
- topographic profi les (unpublished data, courtesy of P
RANZINI
E.,
2006) and new acquired profi les (Fig. 8) a bar similar to that ob-
served in the satellite images (2010) has been identifi ed. These
three bars have different size and distance from the shoreline but
the characters (i.e. depth, orientation and slope) are comparable.
DISCUSSION
LAKE EVOLUTION AND POND GENESIS
Tab 1 - Variation of the erosion/accretion rates (m/
yr) in four reference sectors of the study
area (Fig.1B): A- From S. Rocco Canal to
Chiaro del Porciatti ponds; B - From Chi-
aro del Porciatti ponds to Ombrone mouth;
C - From Ombrone mouth to Marina di
Alberese; D - From Marina di Alberese to
Colle Lungo Tower. Values from the southern
wing (reported in C and D) are affected by
the presence of a relict road acting as a bar-
rier that hampers erosion of the shoreline.
The dash indicates no signifi cant variation
Fig. 7 - DEM of the submerged delta (left) derived from IIM data (1977). The submerged bar extending from south to north around the Ombrone River
mouth partially isolates a back-bar depression, interpreted as an embryonic stage of pond formation (see further in the text). Close-up of air
photograph of the mouth (A
LISUD
, 1995) showing an elongated spit but at different scale
background image
C. TARRAGONI, P. BELLOTTI & L. DAVOLI
12
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
The analysis of historical maps (1823, 1832, 1851, 1871 and
1883) has provided evidence of a lake located landward of the
Chiaro Grande pond and XIX century beach ridge (T
ARRAGONI
et alii, 2011). This evidence is further supported by the current
morphology of the area that hosted the lake, which is markedly
fl at and is still periodically (wet season) drowned under a water
table up to 30-40 cm high (Fig. 8).
According to B
ELLOTTI
et alii, (2004), who identifi ed rem-
nants of the lake on historical maps, the historical lake under-
went progressive shrinking during the 20
th
century as shown in
the 1883 map (Fig. 3). During the XIX century, the lake preserved
its geometry, characterized by an elongated shape and with two
branches on the landward side (1823 and 1832); of which the
northernmost was divided into two sub-branches oriented NW-
SE (the longest) and S-N (the shortest).
In the 1832 maps it is possible to observe the seaward edge
becoming more undulated; only at the end of the century (1883)
the seaward side presents an irregular geometry likely related to
the effects of washover events (B
ELLOTTI
et alii, 1999). This evi-
dence suggests that no other beach ridge existed in front of beach
ridge confi ning the lake in 1883 and suggests an erosional regime
existed along this coastal sector (phase 4).
The fi rst map reporting the ponds is that of 1929, therefore
their genesis occurred between 1883 and 1929; the ponds cut three
beach ridges. This suggests a strong progradation occurred in this
time interval: indeed, at the end of the fi rst stage of reclamation, at
the end of XIX century, the last historical progradation phase oc-
curred (phase 5). Moreover, the presence of ponds marks the end
of interaction between the lake and the sea. Therefore, by this time,
the fi lling of the lake had changed the sediment deposition regime.
The rate of infi lling has depended on local sedimentation. Accord-
ing to A
DLAM
(2014), the volume of accommodation space (intend-
ed as total subaqueous volume) is considered including effective
accommodation space; this latter could be assumed exhausted but
total accommodation space remains due to water table excursions.
As noted above, the single beam eco-sounding surveys (May
and June 2009) characterize the different submerged morphology
of ponds: the pond-fl oor, narrow and deep (mean depth 3.5 m), and
the depression (markedly fl at, periodically drowned under a water
table up to 30-40 cm high and coinciding with the lake reported
in historical maps). The wide diversity of shape and bathymetry
values and the evidence from the analysis of historical and recent
maps, indicate that the genesis of ponds is independent from the
lake and different between the ponds (T
ARRAGONI
et alii, 2011).
Both ponds present a depth of about 3.5/4 m but their origins
are different.
CHIARO GRANDE POND
The location of the Chiaro Grande pond is between two ridges
and parallel to the shoreline of historical maps (e.g. 1832): a pond
would form if a bar emerged isolating the stretch of sea behind it.
Some examples of the stages during which such a bar emerg-
es and transforms into a spit are shown in fi gure 2 where it is
possible to observe submerged bar (on the left), incipient spit (D
and E) and a new ephemeral chiaro (C) (1998).
The fi gure 6 shows the status of 1995: the spit extends along-
strike to the Ombrone River mouth, from the southern wing apex
to the northern one. Concomitant with the isolation of the stretch
of sea behind it, the river mouth is forced to move ca. 500 m
northward, resulting in a 90° bend in the fi nal course of the river.
On the northern wing, it is possible to recognize the strong dyna-
mism of the beach during the time interval 1995-2010: several
ponds, characterized by different position and size, have been
formed according to the mechanism just described.
The geometry of Chiaro Grande pond (B in Fig. 2) is somewhat
similar to that recognized analysing the submerged mouth’s DEM
(Fig. 6) where a narrow and elongated (SE-NW) depression has
been observed in front of the northern wing. By analysing several
Fig. 8 - View of the fl at area: A) Map of 1823; B) Google Earth view whit the location of the lake (1823); C) Photo of depression (May 2012 ): observing
fl amingo’s leg it is possible to obtain an estimation of water depth
background image
NATURAL AND ANTHROPOGENIC FORCING DURING THE LAST TWO CENTURIES
IN THE OMBRONE DELTA (SOUTHERN TUSCANY - CENTRAL ITALY)
13
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
cross sections (drawn through the Chiaro Grande’s DEM and sub-
merged mouth’s DEM), has been possible to recognize the similar
morphology (Fig. 9): 1) same depth (about -4 m); 2) same asym-
metric profi le with the SW side of Chiaro Grande pond and of sub-
merged depression having higher slope than their NE counter-side.
The SW side coincides with the leeward side of the beach ridge in
the Chiaro Grande pond and with the downdrift side of the bar in the
submerged depression; the NE side coincides with the windward
side of the next beach ridge in the Chiaro Grande pond and with
the overwash side of the seafl oor in the submerged depression (Fig.
8). This consideration supports the suggestion of T
ARRAGONI
et alii
(2011) regarding the mechanism of Chiaro Grande pond genesis.
CHIARO DEL PORCIATTI PONDS
The Chiaro del Porciatti ponds have an orientation transverse
to the coast, cutting the ridges, and present a branched structure,
in marked contrast to Chiaro Grande pond. On the other hand, the
presence of two anthropic structures suggest an anthropic genesis
for these ponds. In this area, there were several drainage works
and this suggests it is remains of an ancient drainage canal.
SHORELINE VARIATIONS
The evolution of this coastal area has been confi rmed by fi eld
work carried out during 2007, 2008, 2009 and 2010. Coastal
ponds observed during the 2007, 2008 and 2010 surveys ap-
peared of different size, the latter being signifi cantly smaller;
in 2010 three new little ponds were observed (Fig. 6). Similar
changes have also been observed during shorter (seasonal) time
intervals: the current erosive regime acting along the coast does
not allow the conservation of these forms.
Several authors recognize climate change as a forcing of a
river’s solid transport (E
LY
et alii, 1993; K
NOX
, 1993; M
ILLY
et
alii, 2002; M
ACHLIN
& L
EWIN
, 2003; P
IVA
et alii, 2008) due to the
increase of precipitation combined with intense forest clearance;
other authors consider human activity as a forcing (i.e. A
LESSAN
-
DRO
et alii, 1990; I
NNOCENTI
& P
RANZINI
, 1993).
Based on the review of existing data and integration with
newly acquired bathymetric data we propose a re-interpretation
of the coastal evolution (B
ELLOTTI
et alii, 1999a) along the area of
the Ombrone delta during the past two centuries.
Most of the major Italian deltas (Po, Tiber and Arno), entered a
progradational phase during the Medieval cooling which culminat-
ed in the Little Ice Age (LIA) and deltaic plains went through sig-
nifi cant expansion although hampered by local human activities.
Probably, the 1823 shoreline (Fig. 3 and 8) limited the plain
at the end of phase 3. The delta plain expansion occurred in a cold
and rainy interval between the Late Middle Ages and throughout
the phase 3. Increased rainfall allowed frequent fl oods with higher
fl ow rates, which have been historically documented (Arno River:
1333, 1557, 1680, 1758; Ombrone River: 1318, 1333, 1557, 1758;
Fig. 9 - Each pair of profi les has the same (horizontal and vertical) scale. The seafl oor cross-sections (acquired in 2010) are oriented from SW to NE while
that ones of Chiaro Grande pond are oriented from SSW to NNE; both are represented with the seaward side on the left and the landward side on
the right. The position of cross-section are shown in fi gure 3 (seafl oor profi les) and fi gure 4 (Chiaro Grande profi les)
background image
C. TARRAGONI, P. BELLOTTI & L. DAVOLI
14
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
Tiber River: 1422, 1476, 1495, 1530, 1557, 1598, 1606 e 1637). In
the same areas, the Late Middle Ages and Renaissance were times
of agricultural expansion and consequent deforestation (S
ERENI
,
1987) except for the second half of XIV century, during which
the population decreased signifi cantly after the Black Death: K
U
-
KAVICIC
& P
RANZINI
(2003) relate the erosion stage of phase 2 to
reduced sediment input during the Black Death.
The next erosion stage (phase 4) is probably due to the con-
struction of “La Steccaia” dam and the great drainage works, be-
tween 1830 and the end of the XIX century. The new prograda-
tion stage (phase 5) starts around the end of XIX century when
the main drainage network was completed. The control of fast
fl owing rivers and the warming climatic conditions have trig-
gered the current erosion stage (phase 6).
Focusing on recent data, fi ve shoreline positions (1995, 1998,
2004, 2006 and 2010) have been analyzed (Fig. 5): the com-
parison allows identifi cation of beach erosion and progradation
periods and associated rates. Comparison of the rates shown in
table 1 indicates that the sediment eroded from the apex is largely
dispersed toward the north (A
IELLO
et alii, 1975). Indeed the spit
and bar shapes are elongated toward the north and the sector “A”
(between Chiaro del Porciatti ponds and Emissario S. Rocco Ca-
nal) has an accretion rate bigger than the erosion rates of the same
wing. For the last interval (2006-2010), the reduction in erosion
rate is probably due to the combination of some factors such as:
- The orientation of the delta with respect to the direction of the
wave front (southern quadrants, Fig. 10);
- The presence of a rigid structure in the southern wing that
prevents its retreat and cuts the supply of sediment from long-
shore drift;
- The northward river sediment dispersion.
The southern wing, in this setting, plays a protective role with
respect to the northern one which is in a sheltered position.
CONCLUSIONS
We present new data to update the Ombrone delta apex mor-
phological evolution.
Comparing historical maps and analysing the morpho-bathym-
etry of submerged delta and ponds, we suggest that the genesis of
ponds and lake evolution are independent and in particular:
- during the XIX century, the historical lake preserved its geo-
metry; only in the 1883 map seaward side presents an irregu-
lar geometry, probably due to washover events that suggests
no other beach ridge existed in front of beach ridge confi ning
the lake. In the 1929 map the ponds have been represented for
the fi rst time and are located seaward with respect to the XIX
century beach ridge.
- the morpho-bathymetrical study of Chiaro Grande pond and
submerged apical mouth confi rmed the hypothesis about
Chiaro Grande pond genesis in which its formation is based
on the closure of a narrow sea stretch consequent to the emer-
gence of a bar.
The orientation of morphological features such as spit, bar
and pond together with the spatial distribution of erosion/progra-
dation rates and the prevailing wave climate point top sediment
transport from south to north. The progressive landward migra-
tion of the shoreline has resulted in a realignment of the coast,
reducing drastically the cuspate shape of the Ombrone delta. Re-
cently, the erosion rate of the northern wing has reached peaks of
around 14 m/yr (2004-2006), and then fallen to 4.5 m/yr in the
latest period (2006-2010). This lower rate is probably due to the
orientation of the delta with respect to the direction of the wave
front (that is responsible for the northward sediment dispersion)
and presence of a rigid structure in the southern wing that cuts
sediment supply and stabilizes the shoreline.
ACKNOWLEDGEMENTS
The authors would like to thank Andrew Cooper for his valu-
able guidance and suggestions, Marco Mancini for his help and
Federico Falcini for his collaboration during the boat surveys in
the Chiaro Grande and Chiaro del Porciatti ponds.
Fig. 10 - View of Ombrone mouth and wave climate of Capo Linaro
wave metric station (the nearest one to the study area)
REFERENCES
AA.VV. (2010) - Final report of VECTOR Project. V.E.C.T.O.R. Project. Unpublished report.
A
DLAM
K. (2014) - Coastal lagoon: geologic evolution in two phases. Marine Geology, 355: 291-296.
background image
NATURAL AND ANTHROPOGENIC FORCING DURING THE LAST TWO CENTURIES
IN THE OMBRONE DELTA (SOUTHERN TUSCANY - CENTRAL ITALY)
15
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
A
IELLO
E., B
ARTOLINI
C., C
APUTO
C., D’A
LESSANDRO
L., F
ANUCCI
F., F
IERRO
G., G
NACCOLINI
M., L
A
M
ONICA
G.B., L
UPIA
P
ALMIERI
E., P
ICCAZZO
M. & P
RANZINI
E. (1975) - Il trasporto litoraneo lungo la costa toscana fra la foce del Fiume Magra ed i Monti dell’Uccellina. Boll. Soc. Geol. It., 94: 1519-1571.
A
LESSANDRO
V., B
ARTOLINI
C., C
APUTO
C. & P
RANZINI
E. (1990) - Land use impact on Arno, Ombrone and Tiber deltas during historical times. In: Quélennec,
R.E., E
RCOLANI
, E., M
ICHON
, G., (Eds.), Littoral 1990, Eurocoast, pp. 261-265.
A
MOROSI
A., P
ACIFICO
A., R
OSSI
V. & R
UBERTI
D. (2012) - Late Quaternary incision and deposition in an active volcanic setting: the Volturno Valley Fill,
southern Italy. Sedimentary Geology 242: 307-320.
A
RNAUD
-F
ASSETTA
G., B
RUNETON
H., B
ERGER
J., B
EAUDOUIN
C., B
OES
X. & P
ROVANSAL
M. (2005) - A ~8,000-yr record of palaeohydrology and environmental
change in fl uvialinfl uenced sediments from Arles-Piton core, upper Rhône Delta, France. Z. Geomorph. N.F. 49: 455-484.
B
ELLOTTI
P. (2000) - Il modello morfo-sedimentario dei maggiori delta tirrenici italiani. Boll. Soc. Geol. It., 119: 777-792.
B
ELLOTTI
P., C
APUTO
C., D
AVOLI
L., E
VANGELISTA
S., G
ARZANTI
E., M
ORETTI
F
OGGIA
F. & V
ALERI
P. (1999a) - La piana deltizia del Fiume Ombrone (Toscana
meridionale): morfologia - tessitura e composizione dei sedimenti - architettura del sottosuolo. Atti del convegno “Le pianure, conoscenza e salvaguardia.
Il contributo delle scienze della terra”. University of Ferrara, 8 -11 November 1999.
B
ELLOTTI
P., C
APUTO
C., D
AVOLI
L., E
VANGELISTA
S. & V
ALERI
P. (1999b) - Lineamenti morfologici e sedimentologici della piana deltizia del Fiume Ombrone
(Toscana meridionale). Boll. Soc. Geol. It., 118: 141-147.
B
ELLOTTI
P., C
APUTO
C., D
AVOLI
L., E
VANGELISTA
S., G
ARZANTI
E., P
UGLIESE
F. & V
ALERI
P. (2004) - Morpho-sedimentary characteristics and Holocene
evolution of the emergent part of the Ombrone river delta (southern Tuscany). Geomorphology, 61: 71-90.
B
ELLOTTI
P., C
APUTO
C., D
AVOLI
L., E
VANGELISTA
S. & P
UGLIESE
F. (2003) - Evolutionary dynamics of the Crati River Delta (Italy). Proceeding of the Sixth
International Conference on the Mediterranean Coastal Environment, MEDCOST 03, E. Ozhan (Editor), 7-11 October 2003, Ravenna, Italy, 1805-1816.
B
ELLOTTI
P., C
APUTO
C. & V
ALERI
P. (2012) - Tipologie deltizie lungo le coste della penisola italiana. Considerazione sui fattori evolutivi. Act of 4°
International Symposium “Il monitoraggio costiero mediterraneo: problematiche e tecniche di misura”. Livorno, 12-14 June 2012, 99-100.
B
ELLOTTI
P., C
HIOCCI
F.L., M
ILLI
S., T
ORTORA
P. & V
ALERI
P. (1994) - Sequence stratigraphy and depositional setting of the Tiber Delta: integration of high-
resolution seismics, well-logs and archaeological data. Journ. Sedim. Res., 64 (B): 416-432.
B
ONDESAN
M., B
AVERO
V. & V
IÑALS
M.J. (1995) - New evidence on the evolution of the Po delta coastal plain during the Holocene. Quatern. Internat. 29/30:
105-110.
B
RAMBATI
A
NTONIO
(2011) - La Costa del Friuli Venezia Giulia. In: La costa d’Italia (2011), Delfi no, Sassari.
B
RAVETTI
L. & P
RANZINI
G. (1987) - L’evoluzione quaternaria della pianura di Grosseto (Toscana): prima interpretazione dei dati del sottosuolo. Geografi a
fi sica e Dinamica Quaternaria, 10: 85-92.
C
HIOCCI
F.L., T
OMMASI
P., M
ELIS
F. & O
RTOLANI
U. (2011) - Morfologia, sismostratigrafi a ed elementi di instabilità gravitativa nella conoide sommersa dei F.
Ombrone. In: “Bilancio sedimentario dei sistemi costieri italiani. Processi naturali e infl uenze antropiche”. Riassunti delle comunicazioni orali, Ischia,
15-17 maggio 2001.
C
ORREGGIARI
A., C
ATTANEO
A. & T
RINCARDI
F. (2005) - The modern Po Delta system: lobe switching and asymmetric prodelta growth. Marine Geology, 222-
223: 49-74.
D
ELLA
R
OCCA
B., M
AZZANTI
R. & P
RANZINI
E. (1987) - Studio geo-morfologico della Pianura di Pisa. Geografi a Fisica e Dinamica Quaternaria, 10: 56-84.
D
I
B
ELLA
L., F
REZZA
V., B
ERGAMIN
L., C
ARBONI
M.G., F
ALESE
F., M
ARTORELLI
E., T
ARRAGONI
C. & C
HIOCCI
F.L. (2014) - Foraminiferal record and high
resolution seismic stratigraphy of the Late Holocene succession of the submerged Ombrone River Deltas (Northern Tyrrhenian Sea, Italy). Quaternary
International, 328-329: 287-300.
D
IAZ
J.I., N
ELSON
C.H., B
ARBER
J
R
. J.H. & G
IRO
S. (1990) - Late Pleistocene and Holocene sedimentary facies on the Ebro continental shelf. In: N
ELSON
, C.
H. & M
ALDONADO
, A. (eds.), The Ebro Continental Margin, Northwesthern Mediterranean, Spec. Issue. Marine Geol. 95: 333-352.
E
LY
L.L., E
NZEL
Y., B
AKER
V.R. & C
AYAN
D.R. (1993) - A 5000-year record of estreme fl oods and climate change in the southwestern United States. Science,
262: 410-412.
F
ERRARI
K., D
ALL
’A
GLIO
P.L., B
ELLOTTI
P., D
AVOLI
L., D
I
B
ELLA
L., E
SU
D., T
ORRI
P. & B
ANDINI
M
AZZANTI
M. (2013) - Holocene landscape evolution at the
Garigliano Rover Mouth. Annali di Botanica, 3: 191-198.
F
IRPO
M., P
ICCAZZO
M., B
ONCI
M.C., I
VALDI
R. & P
OGGI
F. (1992) - Il delta sommerso del fi ume Centa (Albegna): caratteristiche morfologiche e stratigrafi che.
Proceeding of X A.I.O.L. Conference, Alassio, 4-6 November 1992, 587-602.
G
ALLOWAY
W
ILLIAM
E. (1975) - Process frame work for describing in the morphologic and stratigraphic evolution of deltaic depositional system. In:
B
ROUSSARD
M.L. E
D
. Deltas, Model for Exploration. Houtson Geol. Soc., 87-98.
G
ENSOUS
B., W
ILLIAMSON
D. & T
ESSON
M. (1993) - Late Quaternary transgressive and highstand deposits of a deltaic shelf (Rhône delta, France). I.A.S.
Special Issue, 18: 197-211.
I
NNOCENTI
L. & P
RANZINI
E. (1993) - Geomorphological evolution and sedimentology of the Ombrone river delta, Italy. Journal of Coastal Research, 9/2:
481-493.
background image
C. TARRAGONI, P. BELLOTTI & L. DAVOLI
16
Italian Journal of Engineering Geology and Environment, 1 (2015)
© Sapienza Università Editrice
www.ijege.uniroma1.it
K
NOX
J
AMES
C. (1993) - Large increases in fl ood magnitude in response to modest changes in climate. Nature, 361: 430-432.
K
UKAVICIC
M. & P
RANZINI
E. (2003) - Beach ridges and dunes of the Arno River delta. Proceeding of the Sixth International Conference on the Mediterranean
Coastal Environment, MEDCOST 03, E. Ozhan (Editor), 7-11 October 2003, Ravenna, Italy, 1413-1424.
L
AMBECK
K., A
NTONIOLI
F., P
URCELL
A. & S
ILENZI
S. ( 2004) - Sea-level change along the Italian coast for the past 10,000 ky. Quaternary Science Reviews,
23, Issues 14-15: 1567-1598.
L
AMBECK
K., A
NTONIOLI
F., A
NZIDEI
M., F
ERRANTI
L
., L
EONI
G., S
CICCHITANO
G. & S
ILENZI
S. (2011) - Sea level change along the Italian coast during the
Holocene and projections for the future. Quaternary International, 232, Issues 1-2: 250-257.
M
ACKLIN
M.G. & L
EWIN
J. (2003) - River sediments, great fl oods and centennial-scale Holocene climate change. Journal of Quaternary Science, 18: 101-105.
M
ARINELLI
O
LINTO
(1926) - Sull’età dei delta italiani. La Geografi a, 14: 21-29.
M
ILLI
S., D’A
MBROGI
C., B
ELLOTTI
P., C
ALDERONI
G., C
ARBONI
M.G., C
ELANT
A., D
I
B
ELLA
L., D
I
R
ITA
F., F
REZZA
V., M
AGRI
D., P
ICHEZZI
R.M. & R
ICCI
V.
(2013) - The transition from wave-dominated estuary to wave-dominated delta: the Late Quaternary stratigraphic architecture of Tiber River deltaic
succession (Italy).
Sedimentary. Geology 284-285: 159-180.
M
ILLY
P.C.D., W
ETHERALD
R.T. D
UNNE
K.A. & D
ELWORTH
T.L. (2002) - Increasing risk of great fl oods in a changing climate. Nature, 415: 514-517.
P
IVA
A., A
SIOLI
A., T
RINCARDI
F., S
CHNEIDER
R.R.. & V
IGLIOTTI
L. (2008) - Late-Holocene climate variability in the Adriatic Sea (Central Mediterranean).
The Holocene 18: 153-167.
P
RANZINI
E. (1994a) - The erosion of the Ombrone river delta (Italy). Littoral 94, Lisbona, Portogallo, 26-29 September 1994.
P
RANZINI
E. (1994b) - Bilancio sedimentario ed evoluzione storica delle spiagge. Il Quaternario, 7: 197-204.
P
RANZINI
E. (2001) - Updrift river mouth migration on cuspate deltas: two examples from the coast of Tuscany (Italy). Geomorphology, 38: 125-132.
R
OMANO
P., S
ANTO
A. & V
OLTAGGIO
M. (1994) - L’evoluzione geo-morfologica della Pianura del Fiume Volturno (Campania) durante il tardo Quaternario
(Pleistocene medio superiore-Olocene). Il Quaternario, 7 (1): 41-56.
S
ACCHI
M., M
OLISSO
F., P
ACIFICA
A., V
IGLIOTTI
M., S
ABBARESE
C. & R
UBERTI
D. (2014) - Late-Holocene to recent evolution of Lake Patria, South Italy: an
example of a coastal lagoon within a Mediterranean delta system. Global and Planetary Change, 117: 9-27.
S
ERENI
E
MILIO
(1961) - Storia del paesaggio agrario italiano. Laterza Editore, Bari 1999.
S
OMOZA
L., B
ARNOLAS
A., A
RASA
A., M
AESTRO
A., R
EES
J.G. & H
ERNANDEZ
-M
OLINA
F.J. (1998) - Architectural stacking pattern of the Ebro delta controlled by
Holocene high-frequency eustatic fl uctuation, delta-lobe switching and subsidence precesses. Sedimentary Geology, 117: 11-32.
S
TANLEY
J.D., B
ERNASCONI
M.P.E. & J
ORSTAD
T.F. (2008) - Pelusium, an ancient port fortress on Egypt’s Nile Delta coast: its evolving environmental setting
from foundation to demise. Journal of Coastal Research, 24/2: 451-462.
S
TANLEY
J.D. & W
ARNE
A.G. (1993) - Nile Delta: recent geological evolution and human impact. Science, 260: 628-634.
T
ARRAGONI
C, B
ELLOTTI
P., D
AVOLI
L. & C
HIOCCI
F. L. (2009) - Recent evolution of the apical area of Ombrone River Delta (Southern Tuscany). Epitome
Geoitalia 2009, FIST Journal, 3: 417-418. Rimini, 9-11 September 2009.
T
ARRAGONI
C, B
ELLOTTI
P., D
AVOLI
L., P
ETRONIO
B.M. & P
IETROLETTI
M. (2011) - Historical and recent environmental changes of the Ombrone Delta (Central
Italy). JCR, Special Issue 61: 344-352.
Web sites
http://it.bing.com, 2010
http://maps.live.it, 1998
http://www.visual.paginegialle.it, 2006
http://www.wadi.unifi .it/grosseto_plain_ital.pdf, 2010
Received September 2014 - Accepted May 2015
Statistics