Beaches’ Expulsion from Paradise: From a Natural to an Artificial Littoral in Tuscany (Italy)

Abstract

This study investigated the shoreline evolution of the Tuscany coast (Italy) from 1878–1883 to 2019. The 205 km sandy coastline, divided into 821 sectors, each one 250 m long, was analyzed to understand how human activities have altered this once-pristine coast. Sub-period analyses highlighted the impacts, both positive and negative, of various shore-protection projects. Initially, regional beaches were undeveloped and accreting, except for a few river deltas where alternating phases of erosion and accretion were observed. Coastal erosion began at deltas’ areas due to the reduction in sediment inputs and, at other areas, enhanced by the development of human settlements and tourism activities. This triggered the construction of protection structures that shifted erosion processes downdrift, a process that induced the downdrift extension of the structures (according to the “domino” effect), determining the transformation of a completely natural and resilient environment into a largely rigid one. Beach nourishment projects, mostly using inland quarries, added about 1 million cubic meters of sediment from the 1980s to 2019. Currently, 57.8% of beaches are larger than in the 1880s, 9.4% did not change and 32.8% are narrower. Overall, the Tuscan coast gained 6.5 km² of beach surface with an average shoreline advancement of 32 m. Recent trends (2005–2019) show that 37.7% of the coast is eroding, 21.1% is stable, and 41.2% is accreting, with a total surface area increase of about 200,000 m². The beach surface area is still increasing despite the existing reduced sediment input due to the limited sediment loss resulting from the presence of morphological cells enclosed by very prominent headlands and the absence of submarine canyons that would otherwise direct sediments to the continental shelf.

1. Introduction

The allure of the coastal environment long captivated humans due to its inherent benefits, including a mild climate, fertile lands for agriculture, a facility for marine commerce and abundant leisure opportunities [1]. This enduring attraction persists despite the challenges posed by beach erosion, land subsidence and floods from both the sea and rivers [2]. Throughout history, humans were drawn to coasts while maintaining a respectful distance from the water. Houses and shelters were rarely constructed directly on the beach, reflecting an awareness of the inherent risks. Despite offering opportunities for food availability and a facility for travel and commerce, the sea was often perceived as an unfriendly realm populated by mythical creatures. On early European maps, unknown lands and oceans were rich with these fantastic creatures, but they disappeared from the land as it was explored and colonized, while in the seas, they remained even after Europeans had crossed all of them, though they ended up forming only decorative elements [3].

The sea was frequently viewed as a place of the dead, with rites of passage celebrated on the beach. Some wooden walkways found in marshy areas of England were interpreted as points of contact with the afterlife, complete with votive objects found at their ends [3]. Another reason for avoiding proximity to the water was the fear of enemies and pirate attacks, a concern prevalent along coastlines worldwide that still lingers. “A furore Normannorum libera nos, Domine” (“From the fury of the Northmen deliver us, Lord”) is said to have closed prayers in monasteries along the British coasts during the High Middle Ages. In Italy and beyond, as early as the sixteenth century, government institutions and religious confraternities for the ransom of poor slaves developed with the aim of collecting the necessary sums to release Christians enslaved by Muslims [4].

In Tuscany (Italy, Figure 1), the population’s apprehension about living too close to the shoreline is evident in the names of many settlements developed over past centuries on hills facing the sea, carrying the epithet ‘Marittima’ (e.g., Castellina Marittima, Rosignano Marittimo, Monteverdi Marittimo, Massa Marittima). At that time, Tuscany effectively ended at the line of hills bordering the coastal plain that often hosted several wetlands favoring malaria endemicity.

This did not imply avoiding all contact with the sea, but such interactions were limited to places where it was necessary to dock boats or build military outposts to anticipate the arrival of enemies and avoid clandestine landings of people and goods associated with the risk of epidemic infections, primarily the plague [5]. Most of the Tuscan coast remained largely deserted and in a pristine state until the 18th century. This was an area considered as the kingdom of the devil but that, nowadays, would be considered as a paradise!

Historically, beach progradation was a predominant trend facilitated by human activities, primarily the felling of forests within hydrographic basins. Exceptions were recorded during periods of demographic declines such as the fall of the Western Roman Empire and the Black Death [6]. Erosion processes, mostly affecting river deltas, had no impacts on the population since affected areas were sparsely populated, not only due to their unsafe and unhealthy environment but also because of their very recent formation. Written documents and comparisons among ancient maps [7,8] revealed that, at least until the mid-1800s, almost the entire Tuscany coast was experiencing accretion. During that time, the Grand Duke of Tuscany liberalized the cutting of woods to facilitate agricultural expansion due to a rapidly growing population and the need for wood production for home heating (it still was the Little Ice Age). The resulting soil erosion provided the rivers with an enormous quantity of sediment to feed the coasts, even if some of it was deposited in the areas subject to land reclamation. At that time, the primary concern for coastal evolution was beach widening and not erosion.

The intense accretion led to the watchtowers moving away from the shore and the creation of dunes in front of them. This shift rendered the watchtowers ineffective, necessitating the construction of new ones close to the new shoreline. Notably, the first known coastal monitoring network consisted of three milestones placed on the northern side of the Arno River delta (at San Rossore, Figure 1), where the distance from the ‘retreating’ sea in the year 1829 was engraved [9].

In the second half of the 19th century, better environmental conditions resulting from marsh reclamation, relative military safety and, above all, the development of communication routes that needed to run over flat lands [10] provided the impetus for the populating of the coastal zone. Hill-top villages led to new settlements at the base of the hills along the railway, often named Scalo (station), while those located near the shoreline were called Marina (different from Marittima), especially when seaside tourism began to develop. Regrettably, those developments coincided, as we shall see, with a reversal of coastal dynamics from accretion to erosion, and the new settlements immediately had to resort to increasingly massive protection structures, transforming that paradise into a hell.

In an 1845–1846 French nautical map (scale 1:100,000), the only settlement present along the sandy coast of Tuscany was Viareggio, built in the mid-15th century at the mouth of a channel draining a wetland area. Two short jetties were constructed here in the 16th century and were further extended to prevent siltation at the channel mouth [11]. Similar rocky structures had existed since the 17th century at the mouth of the Bruna River, which receives an artificial channel draining coastal lagoons and marshes.

No other jetties or breakwaters were present on the sandy coast of Tuscany, and the only structures were watchtowers and fortresses, serving as military vanguards for small garrisons [5]. Most of those built on the beach in the 18th century are now separated from the sea by dunes formed later, at sites leveled after World War II to build houses (Figure 2).

Some piers are indicated on 19th century maps, specifically designed for loading marble (Marina di Carrara, Marina di Massa, Forte dei Marmi) or cast iron (Follonica). After World War II, some of these piers were reconstructed, restored and repurposed as tourist attractions. Additionally, two new piers were constructed in the first decade of the 21st century at Marina di Pietrasanta and Lido di Camaiore, solely for the enjoyment of visitors. It is intriguing to note the presence of beach clubs from that time, which were constructed on platforms supported by wooden poles (Figure 3). Similar structures existed at Viareggio and Marina di Pisa (just before the establishment of the two settlements), while they were absent on the central and southern Tuscany coast, where the Sun, Sea and Sand (3S) tourism arrived later.

Even with the necessary caution when working with the earliest small-scale geodetic maps, which must be interpreted in the context of contemporary written documents, it is possible to consider the Italian topographic map surveyed in 1878–1883 (scale 1:50,000) as a representation of Tuscany at a time when no erosion was evident along any coastal stretch. From that point, the emergence and evolution of the erosion processes can be traced; it was countered with a spatially and temporally limited perspective. Only a long-term historical analysis enables us to accurately contextualize current processes and formulate the most suitable coastal management strategies.

2. Study Area

The Tuscany region’s continental coast in NW Italy is 397 km in length and faces the Ligurian Sea in its northern and central parts and the Tyrrhenian Sea in its southern one (Figure 4). Coastal orientation broadly varies from NNW–SSE, from R. Magra mouth to Piombino, to NW-SE, from Piombino to the southern limit of the region. Local variations in coastal orientation are observed at Follonia, Punta Ala, Albegna and Feniglia cells.

Rocky sectors, for a total of 192 km, extend between Livorno and Rosignano, at the Piombino, Scarlino, Punta Ala, and Uccellina headlands and at Monte Argentario, which is connected by two tombolos with the mainland.

It is a microtidal environment with an astronomical tidal range of 35 cm. Beaches cover 205 km and are composed of medium to fine sand, with limited sectors of mixed sand and gravel near the mouths of the rivers, reaching the sea with a steep gradient or crossing narrow coastal plains (e.g., R. Magra and R. Cecina). Sediments, rich in quartz and carbonates but containing feldspars and heavy minerals, too [12], are mostly produced by the erosion of the Northern Apennine Mountains and carried to the sea by different rivers. It is important to note that river sediment supply was largely reduced in the past century due to reforestation within watersheds, river bed quarrying, and the construction of weirs and dams. This was the case of the River Arno, which is the most relevant with 241 km in length. Sediment input was approximately 9,300,000 t yr⁻¹ during the 1500–1800 AD period and was reduced to only 1,524,000 t yr⁻¹ in the 1980s [6,13].

The coast is exposed to high energy waves from W and SW that, considering a 50-year return period, can reach 7.5, 8.5 and 6.0 m in the northern, central and southern part of the Tuscany coast, respectively (Figure 4). The longshore transport direction and the extension of the littoral cells are a consequence of the way in which the coast is oriented with respect to approaching wave fronts.

There are also local inversions in longshore transport due to refraction and diffraction phenomena around islands, promontories and shoals. The depth of closure, calculated according to the formula of Hallermeier [14] for a period of 50 years, ranges from −14.0 m in the most exposed coastal stretches to −5.5 in the most sheltered [15].

Figure 4. Physiographic sketch of the continental Tuscany coast showing main littoral cells, longshore transport directions, long-term evolution and shore-protection structures. Extreme values of offshore waves, i.e., significant wave height (H_s), associated mean period (T_m) and approaching direction values for three European Centre for MediumRange Weather Forecasts points are also reported [15].

Figure 4. Physiographic sketch of the continental Tuscany coast showing main littoral cells, longshore transport directions, long-term evolution and shore-protection structures. Extreme values of offshore waves, i.e., significant wave height (H_s), associated mean period (T_m) and approaching direction values for three European Centre for MediumRange Weather Forecasts points are also reported [15].

3. Materials and Methods

An extensive collection of documents is available for studying the evolution of the coast over the last 140 years, encompassing both morphological aspects and anthropic settlements. These documents include topographic maps with updates, cadastral maps, aerial photos, landscape prints, single-building representations and vintage postcards, as well as technical and literary descriptions—all of which contribute to a comprehensive analysis of shoreline displacement. The 140-year period available for the Tuscany coast aligns with the timeframe recommended by Crowell et al. [16] as the most suitable for a comprehensive long-term study. A similar time interval was employed for analyzing the evolution of the Volturno River [17] and the Sele River [18] deltas in Italy, starting from the same late-19th century I.G.M. maps used in this paper.

The oldest maps from the Istituto Geografico Militare (I.G.M.), dating back to 1878–1883 (hereafter referred to as ca. 1881; specifically, Versilia 1878; Livorno 1881; remaining coast 1883), were digitally acquired using a flatbed scanner and georeferenced to further digitize the shoreline. The same process was applied to subsequent editions in areas of more focused research. Since only in some coastal sectors are there fixed reference points near the shore (e.g., rocks and towers) while they are absent in most of the coast, any statistical analysis of the error, such as that present in Mićunović et al. [19] on cadastral maps of 1834, is not applicable here. It is also for this reason that we consider our data as semi-quantitative. It would be a mistake to renounce this information, which is the only one, on a regional scale, that can give a picture of historical coastal evolution, albeit with limited accuracy, especially in the areas without settlements, of the state of the Tuscany coast immediately before the beginning of the erosion problems and urban developments.

In addition to the above-described documents, which were not specifically created for coastal monitoring aims, the Tuscany region commissioned to the University of Florence the development of a 1:5000 map with the location, on the basis of air photos, of the shoreline position in 1938, 1954, 1967, 1978 and 1984, with an assessed accuracy of 5 m [20]. This document was later updated by the same university with shorelines acquired, initially, through traditional topographic surveys and later with GPS in RTK mode until 2010. Since 2018, the Consortium LaMMA-Regione Toscana has been updating the regional shoreline databank with synchronous data produced via satellite image processing, validated and accessible for the years 2017 and 2019 at the time of writing. The 205 km of the sandy regional coastline were divided into 821 sectors, each about 250 m long, and shoreline position changes were quantified using the Area-Based System [21]. Considering only the graphic inaccuracy due to a 0.2 mm line thickness on the 1:50,000 scale of the 1881 map, a ±10 m shift in shoreline position cannot be considered substantial even if the comparison is performed with more accurate documents. Therefore, beaches that recorded changes within this variation were classified as ‘stable’ or in equilibrium. Considering maps obtained by photo restitution, a ‘stable’ beach was considered one with a shoreline shift between ±5 m; the range of this class is ±2 m for shorelines directly surveyed on the beach with topographic instruments and tide correction. The different accuracy of the data obtained does not allow us to normalize and report them as meters/year; therefore, they were reproduced in the pie charts of Figure 4 and grouped into classes: erosion, stability and accretion, with class ranges defined on the basis of the data accuracy. Obviously, in shorter periods, the probability that the various coastal sectors present minor variations and, therefore, appear in equilibrium, is higher; on the contrary, the frequency of this class can be reduced in the more recent periods in which its limits shift from ±10 m to ±5 and ±2 m.

This approach was used in this paper, even if not used by many authors, respectful of the different quality of data acquired in different times, during which acquisition techniques have changed significantly. However, as previously written, the used approach is semi-quantitative, in particular when ca. 1881 maps are used. Reconstructing the history of the first shore-protection structures poses challenges, as most original projects to contrast coastal erosion are not available. In the 19th to early 20th century, weak wooden or stone structures were used to combat erosion, and they were progressively strengthened without a defined project. As a result, establishing the date of construction and identifying various consolidation stages is nearly impossible. In many cases, an ante quem date can be determined based on their appearance on topographic maps, photographs and postcards.

After a macro-scale analysis of the evolution of the entire Tuscany beaches, most relevant littoral cells (or physiographic units, Figure 1 and Figure 4), namely, the Northern, the Central, Follonica and Ombrone littoral cells, will be analyzed, and the impact of anthropic structures that significantly influenced coastal evolution will be described. This involves zooming into specific sectors of the coast and analyzing periods when these processes were most impactful. Because of the large quantity of protection structures built and their modifications, we are forced to concentrate on the most important projects, going into detail only in some representative cases.

4. Results and Discussion

4.1. A Macro-Scale Temporal Overview

Comparing the oldest (ca. 1881) shoreline position with the most recent one (2019, Figure 1 and Figure 4), it is possible to state that 56.4% of the beaches are now wider than they were in ca. 1881; 10.9% experienced an insignificant change (±10 m); and 32.7% are narrower (Figure 5a). Overall, the Tuscan coast gained 6,143,121 m² (6.1 km²) with an average shoreline advancement of about 31 m during the considered period.

During the first sub-period (ca. 1881–1954, Figure 5b), the majority of the coast experienced beach accretion (64.1%). This can be attributed to the fact that in the late 19th and early 20th centuries, only the river mouths were experiencing erosion, and sectors eroding later (e.g., due to harbor construction) lost only a portion of what had accumulated in previous decades. Shore-protection structures began to be constructed, but only along short coastal sectors in front of houses or roads (e.g., at Marina di Pisa and Marina di Carrara). Although this period spans more than 70 years, beach width variations smaller than 10 m occurred in only 10.9% of cases, demonstrating a very dynamic environment. Additionally, some of these ‘stable’ beaches may have experienced a reversal of the evolutionary trend, shifting from accretion to erosion.

The condition of the Tuscan coast worsened in the following period (1954–1984, Figure 5c), with 39.2% of the beaches eroding, despite shore-protection structures expanded to larger coastal sectors (Marina di Massa, Marina di Pisa, Marina di Cecina and Follonica, Figure 1). The increase in coastal sectors experiencing erosion can also be linked to the post-war economic boom, which saw substantial building and infrastructural development in Italy, including significant riverbed dredging.

The expansion of beach protection and the cessation of riverbed dredging imposed by the Toscana region favored the reduction in erosion processes along the coast recorded for the period 1984–2005 (34.3%) and the increase in stable sectors (43.0%, Figure 5d). However, these data refer to a short period of twenty years and should be considered with caution. The change to a limit of ± 2 m for the stability class, used for the 2005–2019 period, is likely responsible for the reduction in stable sectors (21.6%) and the increase in eroding (37.4%) and accreting (40.9%) ones (Figure 5e). The total surface area grew by 201,307 m², with an average beach widening of 1 m. Over the last 140 years, approximately 55 km of the coast (27%) have been stabilized by seawalls, revetments and detached emerged or submerged breakwaters, groins and jetties intercepting sediments; two kilometers of coast, where harbors have been constructed, were not taken into count. Although not specifically addressed in this study, nearshore morphology underwent significant modifications as well. The two main deltas experienced a loss in thickness of more than 5 m from the present shoreline to the 15 m isobath [22]. Additionally, other minor deltas, such as those of the Magra River, Cecina River and Albegna River, were rectified and even lost their submerged fans. The retreat of the beach began at the mouths of major rivers and gradually expanded to lateral coastal sectors [23], a process that was allowed to freely evolve until the emplacement of shore-protection structures commenced. Interestingly, this erosion initially occurred where new settlements were established, e.g., at Marina di Pisa and Marina di Cecina, highlighting the inappropriateness of those urban planning projects.

4.2. The Northern Tuscany Littoral Cell

This 65 km long coast is primarily influenced by two rivers (Figure 1 and Figure 4): the Magra River, whose sediments flow southward, reaching Marina di Pietrasanta, and the Arno River, where sediments diverge southward to Livorno and northward to Marina di Pietrasanta, creating a drift convergence responsible for continuous beach accretion [24,25]. On the southern margin, wave reflection on the oblique Livorno harbor breakwater triggers north-directed longshore currents, creating a convergence point near Tirrenia (Figure 6a).

In the long-term analysis (ca. 1881–2019), the dominant processes are the erosion of the two deltas and the redistribution of their sediments following the longshore transport directions (Figure 6a). However, beach surface increases suggest not only sediment redistribution but also the relevance, albeit reduced, of river input. This assumption is based on the gross hypothesis that dry beach surface is proportional to beach volume. The above-described process is disrupted by the impact of several coastal structures built in the 20th century (Figure 6a), notably, two harbors:

• Marina di Carrara Harbor, whose breakwater extends to a depth of 10 m, triggered updrift expansion where erosion should have originated from the Magra River mouth and, simultaneously, it induced or exacerbated erosion to the south, i.e., at Marina di Massa.
• Viareggio Harbor is responsible for substantial accretion of the updrift beach (south) and limited expansion of the downdrift one, where sediments arrive, bypassing the breakwater tip, which is at a depth of 5 m, i.e., lower than the depth of closure, approximately 8 m in this area [15]. Immediately after the breakwater extension, the downdrift beach experienced erosion and an artificial bypass system became operative [26].

The asymmetry of erosion at the Arno River delta is attributed to the protection structures emplaced at Marina di Pisa, a process identical to that observed at the mouth of the Volturno River [17]. Minor effects are visible at Gombo, where strong erosion north of the Arno River is partially offset by the construction of five detached breakwaters in the early 1960s. The same occurs 1 km to the north due to the presence of a jetty of a channel draining part of the Pisa plain.

Protection works performed after 2005 resulted in the reversal of the evolutionary trend in some coastal sectors (highlighted in red in Figure 6b):

• Artificial nourishment of the northern beach with sand and gravel dredged from the Magra River terminal course.
• Groins and detached breakwaters at Marina di Massa.
• Sand bypassing at Viareggio.
• Emerged groins with submerged extensions north of the Arno River mouth.
• Gravel beaches protected by submerged breakwaters at Marina di Pisa.
• Oblique jetty near Livorno sequestering sediment via wave diffraction.

Two cases studies are emblematic in this littoral cell: Marina di Carrara harbor impact and Marina di Pisa coastal defense evolution.

4.2.1. Case Study: Marina di Carrara Harbor Impact

The northern 15 km of this coastal cell could be considered a “park” of shore-protection structures given the myriads of protection typologies realized and modified several times over the last 100 years. They include emerged and detached breakwaters, submerged and permeable groins, and artificial islands and were constructed utilizing materials such as rocks, sand-filled bags and tubes (geocontainers), concrete, prefabricated blocks and steel. In the following description, the discussion will be simplified and special attention will be focused only on the main works.

Starting from the north (the left side in Figure 7), it is possible to observe the erosion of beaches directly fed by the Magra River, with values reaching up to 400 m on the 250 m sector, but the delta tip retreated for more than half a kilometer. Most of such erosion occurred from 1881 to 1984 (Figure 7), before the emplacement and modification of various shore-protection structures such as emerged and submerged groins, detached breakwaters and artificial rocky islands. Sediment dredged from inside the terminal river course, mostly gravel, was recently bypassed to the beaches, explaining the beach accretion in sectors 1–6 during the period 2005–2019 (Figure 6b).

Beach erosion did not reach Marina di Carrara, as the harbor constructed in 1920 created strong updrift beach expansion that reached 450 m due to an estimated longshore transport of 70,000 m³/year [27]. However, this process is now interrupted because updrift sectors have been stabilized by various projects, and only limited quantities of sand are available. Consequently, a project to stabilize the northern beach (sectors 8–16) was carried out in two phases (2005–2006 and 2010–2012) with a submerged geotextile T-groin and artificial nourishment of approximately 110,000 m³ of sand quarried from an alluvial plain 160 km away. Just after the construction of the harbor, the downdrift beach began to experience severe erosion, leading shore-protection projects since the 1930s to safeguard the coastal road that, however, had to be abandoned in the late 1930s (Figure 8).

The limited erosion, or even accretion, observed until sector 50 when comparing the 1881 shoreline with that of 2019 (Figure 6a) is attributed to the initial 40-year period benefitting from sediment produced by updrift erosion and the construction of hard shore-protection structures. During this time, multiple projects overlapped, continually altering previously built protections. However, since that period, erosion shifted southward and beaches south of Marina di Massa, although now wider than in 1881, are experiencing severe erosion (Figure 6b; sectors 42–69). Consequently, shore-protection structures are migrating southward according to the “domino effect”, now stretching over 8 km downdrift of the harbor (Figure 9).

Many tourist structures, initially built on the beach just before World War I and flourishing after World War II, have been relocated several times. It was straightforward when they were simple wooden shacks, but it is impossible now since they are large and high brick and concrete structures. Additionally, in many places, the continuous coastal retreat brought tourist structures to be emplaced at the edge of the coastal road (Figure 10), preventing further relocation and necessitating the construction of hard protections, along with beach nourishment, to preserve this vital source of income for the area.

4.2.2. Case Study: Marina di Pisa Coastal Protection Evolution

Marina di Pisa is the result of one of the first interventions by a public administration to promote tourism development along the Italian coasts. The Municipality of Pisa purchased land on the left bank of the mouth of the Arno River in 1872 and divided it into lots, which were sometimes given away free of charge, with the aim of constructing ‘decent’ houses. The area developed on a regular grid, already including planned public spaces [28]. In 1878, only a watchtower was present where Marina di Pisa would later grow. However, development started immediately after, as evidenced by the 1907 map (only for the southern part of the Arno River, as a mapping of territorial transformation), where significant coastal erosion is also visible (Figure 10).

The first shore-protection structures were erected at the very end of the 19th century, contemporaneously with the initial construction of houses in the area (Figure 11). Initially, palisades were constructed, both parallel and perpendicular to the coast, sometimes incorporating stone on the landward side, reminiscent of structures found in the 18th century in Venice [29].

Better-engineered structures were built in the early 20th century, and their presence is documented in the 1928 topographic map (Figure 10). Afterwards, these structures proliferated southward, and construction began with a detached breakwater, which gradually extended to its current length of 2.3 km. Works carried out between 1935 and 1940, as well as from 1965 to 1975, transformed it into a series of ten detached rubble-mound breakwaters with 15–20 m wide gaps between them, which were further closed with submerged segments.

The shoreline was stabilized, but erosion persisted in the nearshore area, particularly in front of breakwaters initially constructed at a depth of 3 m that subsequently increased to 7 m. Since 2000, a structural modification project has been underway in front of the town, involving lowering the crest of the detached breakwaters to sea level and the construction of a gravel beach capable of absorbing wave energy (Figure 6, sectors 206–209). Importantly, this transformation was feasible because this coastal stretch had lost its sandy beach for over a century, rendering it unsuitable for tourist bathing facilities (Figure 12). Therefore, the pebble beach must be regarded primarily as coastal protection infrastructure and cannot be leased to concessionaires, despite its intensive use by bathers [30].

Similarly, a gravel beach was created south of the tenth detached breakwater, where the coastal road was protected only by a revetment [31]. This efficiently dissipates wave energy and allows the road to remain usable even during storm surges, although, after twenty years, it would require a replenishment of gravel. Downdrift of these structures, groins and detached breakwaters were constructed with minimal gaps, following the domino effect starting between 1978 and 1985, but without a comprehensive plan. These structures are not intended to protect housing but to support tourist amenities such as bathing facilities and sandy areas where beach umbrellas can be set up (Figure 13).

From 1881 to 2000, prior to the construction of groins with submerged extensions on the northern side of the delta [32], the shoreline retreated approximately 1300 m, causing the already mentioned asymmetry in the cusp. The southern lobe was the one that mostly suffered; it is a headland heavily impacted by waves that reach protection structures with much of their energy intact due to the seabed depth. Although the coastal road and the first line of houses were built on the dunes at approximately 4 m above m.s.l., the inner part of the settlement lies at a lower height and is susceptible to waves that are able to overtop the revetment. Protection strategies have managed to protect the settlement, but its original purpose as a seaside resort was lost and only partially regained with the creation of the gravel beach. Future sea level rise will necessitate stronger hard protections, which are incompatible with seaside tourism focused on Sun, Sand and Sea tourism.

Retreating inland is a difficult, if not impossible, solution because away from the sea, the settlement loses its value, and any relocation would necessitate moving houses and infrastructure far from the shoreline to areas less prone to flooding. In hindsight, locating a new town close to the shoreline in an area showing initial signs of beach instability, if not yet erosion, was unwise.

4.3. The Central Tuscany Littoral Cell

The coast stretching from Rosignano Solvay to Torraccia (approximately 46 km; Figure 1 and Figure 4) is primarily influenced by the Cecina River, which empties into the northern part of this coastal cell. However, the river’s sediments predominantly move southward due to a net longshore potential transport of 30,000 m³/year (33,000 south–3000 north at the river mouth) [27]. Smaller contributions come from the River Fine, which flows near the northern border and drains a basin, primarily composed of silt-clay sediments, confined landward by a dam. Additionally, there are other short creeks in the southern sector, whose sediment contribution currently lacks morphological evidence and has been identified only through petrographic analyses [33]. However, the 1881 map shows pronounced salients at their mouths, indicating that, at that time, their sediment input was more relevant than it is today. The modest or non-existent growth of the beach at those sectors (around sectors 80–90, Figure 6b) can be explained by their reaching from the adjacent beaches (Figure 14).

An anthropogenic source of sediments is linked to the chemical industry activity of Solvay & Cie, which discharges calcium carbonate sediments (90% finer than 0.625 mm) through an industrial channel. At its peak activity, approximately 200,000 m³/year of sediment were released, leading to a southward beach expansion of about 4.5 km (Sectors 1–22 in Figure 15a), [34,35]. However, this process was later constrained and, in some sections, reversed by the construction of two groins designed to prevent siltation at the Solvay pier in Vada. In all watersheds of the rivers that feed this coast, sediment production has decreased due to reforestation efforts but, in the case of the River Cecina, riverbed quarrying had a more significant impact, resulting in an average lowering of the talweg by 4 m along its 40 km course through the plain [36].

The straightness of this coastline is interrupted by a flat headland located between Vada and Marina di Cecina, which is formed and sustained by a Holocene beachrock platform [37]. Beachrock outcrops are also present in the nearshore of the southern part of this littoral cell, contributing to irregularities along the shoreline [38]. Longshore transport is bidirectional, with a predominant southward movement along most of the coast [27].

There are two tourist ports on this coast: one north of the mouth of the Cecina River and another at San Vincenzo. The first port, constructed between 2010 and 2020 to the right of the Cecina River’s mouth, has impacted both the southern (downdrift) and northern (updrift) beaches.

The San Vincenzo port, built between 2005 and 2010 in an area where a detached breakwater previously protected a few small fishing and recreational boats, has caused a moderate shoreline retreat. This effect was locally mitigated by the construction of a groin, which was later connected to the harbor’s downdrift dike with a submerged breakwater. The impact on the coastline south of this marina is moderate due to the presence of the above-mentioned beachrock. Furthermore, at the southern boundary of this littoral cell, longshore transport is reversed [27], creating a convergence point not far from the marina (Figure 15b).

Several shore-protection structures are present along the northern part of this littoral cell, extending from Rosignano Solvay to Marina di Cecina. These include linear, T- and gamma-groins, some with submerged extension and others oblique to the coast, and emerged and submerged detached breakwaters. It is difficult to estimate the total amount of sand nourished since the 1970s over various years; it is likely around half a million cubic meters was primarily concentrated between Vada and Marina di Cecina.

Case Study: Marina di Cecina

The settlement at the mouth of the Cecina River, initially intended as a landing for goods destined for the villages of the interior and the adjacent coast, did not result from political or administrative decisions but rather from a spontaneous response to the emerging trend of sea bathing. This trend was embraced both by citizens living far from the coast, who aspired to have ‘second home’ by the sea, and by small local entrepreneurs who saw an opportunity to profit by establishing small shops, restaurants, rental houses and, later, hotels. This urbanization process began in 1879 when a concession was granted to soldiers stationed at Villa Ginori for the use of the beach for bathing (Figure 16). In subsequent years, further authorizations were given to private individuals to construct shacks south of the Villa [39].

Starting from 1890, the village developed linearly along the shore, with the innermost strip being settled only when the sea view did not compensate for the inconvenience of the distance from the services that had developed near the first houses (Figure 17). This model of coastal-settlement expansion led to the occupation of the littoral, similar to what occurred in many coastal areas in Italy [40].

As mentioned earlier, erosion within this littoral cell initially began at the mouth of the River Cecina and gradually extended in both directions (Figure 15a). The first shore-protection structure, a short groin, appeared on the 1938 I.G.M. map, though it was likely constructed after 1920 since it is not present in an aerial photo from that period. It was very likely built following the 1935 storms that destroyed some houses on the beach. The groin’s effect is evident in the widening of the beach in front of the Villa (Figure 17), but it also had a negative impact on the downdrift sector where two more groins had to be constructed in front of the settlement between 1954 and 1976. These divided the original linear beach into sectors, each with a triangular shape, creating inequality among the managers of the beach concessions, with extremely wide surfaces updrift of the groins and very narrow surfaces downdrift of them.

At that time, the groins were 60, 100, and 80 m long and spaced 600 and 500 m apart, with an L/d ratio of approximately 1/6, which was insufficient to protect the coast [41]. In the following years, efforts were made to reduce these differences by inserting short intermediate groins. An overall beach expansion was achieved in the early 1990s by adding submerged extensions to the three main groins and carrying out a small beach nourishment (approximately 23,000 m³) using sediments quarried from the Cecina River alluvial plain. Beach monitoring showed that, thanks to the submerged extension, 300,000 m³ of sand accumulated on the nearshore [42].

When this result was achieved, a new project introduced a submerged breakwater in the first cell; a total of 150,000 m³ of sediments were lost due to piling-up processes [43], which triggered a rip current adjacent to the southern groin, where the crest is lower. The detached submerged breakwater was also extended in front of the Villa, where a similar piling-up induced a current that transports sediments to the north, at the river mouth, where the structure is not connected to the shore (Figure 18).

The final solution to the erosion problem, in response to beach concessionaires’ requests, was found by establishing five equally spaced groins and giving them a gamma configuration to limit wave reflection on the southern side (Figure 18). Sand quarried for the construction of the new harbor (approximately 100,000 m³) was used for artificial beach nourishment.

While the town beach was preserved and even expanded, the erosion process accelerated in the downdrift coastal sector; a shoreline retreat of approximately 300 m was registered since 1881 (Figure 15), resulting in the loss of several dune ridges that once supported a pine forest. The need to preserve this environment and the beach, which became more and more popular among those who could not afford or did not like the rental of deck chairs and sun umbrellas, led to the construction of the first groins, quickly followed by two more in a domino effect process. These groins are being transformed into offshore round shoals to reduce their sediment trapping effect. However, eight more shoals were later constructed downdrift to combat beach and dune erosion (Figure 19), thus reducing the sediment input to the southern coastal sector, where a tourist resort is located after 5 km of undeveloped coastline. Although gravel nourishment is carried out on their lee side to mitigate the downdrift effect of these structures, will shore-protection structures soon be necessary at the tourist resort?

On the northern side of the river mouth, a recreational harbor was constructed between 2010 and 2020, effectively acting as a groin and thus obstructing the sediment flow to the northern beach. Short groins were constructed there in the 1990s, and 100,000 m³ of sand, gravel and pebbles were artificially deposited. After the marina’s construction, they had to be soon extended and a gravel/pebble beach nourishment project implemented, resulting in significant beach expansion (sectors 30–40, Figure 15). However, sediments from the river will no longer reach this area, and continuous artificial nourishment will be necessary to maintain the beach, which is intensively used for tourism. The impact of the harbor will also be felt on the southern beach because the river mouth is now sheltered by a breakwater extending 400 m into the sea, preventing aggregates reaching the sea from being moved to the south.

4.4. Follonica Littoral Cell

The 23 km long beach bordering the Gulf of Follonica faces southwest and is protected from the west by Elba Island (Figure 1). According to Bartolini et al. [44], its erosion began in the 19th century when the two rivers feeding this coast (the Cornia River and the Pecora River) were diverted to reclaim coastal wetlands (Figure 20). However, the historical evolution of the river network in the plain is more complex, and these watercourses were emptying into the coastal lagoons before the 19th century, making the identification of the causes of coastal erosion more complex, as written by Mori in 1940 [45]. After World War II, when the rivers were directed straight to the sea, their bedload was reduced by the same processes affecting the other rivers in Tuscany. Additionally, in the early 1970s, a small port serving a power plant was constructed on the eastern side of the new mouth of the Cornia River.

Longshore transport is extremely limited since waves—diffracted by the two headlands delimiting the bay and/or refracted on the mild slope nearshore—always approach almost parallel to the shoreline; however, a prevailing westward potential transport has been identified in the central portion of the gulf [27].

The first erosive hotspots appeared on the western side of the gulf (Figure 20 and Figure 21), where a long breakwater parallel to, but rooted to, the coast attracted sand due to wave diffraction, forming a large salient at the expense of the beach further east. Although the erosion rate was very low along the whole coast, the reduction of the beach in front of the town (which was transitioning from industrial to tourism activities) and of two beach resorts built on the dune in the center of the gulf, led to the construction of hard structures. Initially, a few groins were built, but they had limited effect due to the previously mentioned low longshore sediment transport. Detached breakwaters were subsequently emplaced, which accumulated sediments in the sheltered areas (resulting in a beach wider than in 1976) but caused increased erosion in the adjacent sectors (Figure 21).

In 2000, a marina was built on the eastern extremity of the bay. Although located at the margin of the physiographic unit, it induces a significant sediment flux due to wave diffraction. This has resulted in the formation of a wide beach near its breakwater, while the harbor entrance is continuously silted (Figure 22).

The money spent on the construction and maintenance of hard protection structures until 2005 was calculated to be equivalent to the cost of beach nourishment using offshore sediments capable of maintaining the 1954 shoreline throughout the entire gulf [46]. However, alternative projects to mitigate erosion in a more sustainable way have never been proposed [47].

The effects of projects carried out in the 1980s and 1990s are evident in Figure 20, showing beach accretion in the recently protected sectors and erosion spread throughout the unprotected ones. In recent years (2006–2013), the detached breakwaters in front of Follonica were lowered below mean sea level (approximately −0.5 m) and connected to form a continuous reef [48]. This reduced their landscape impact and improved water quality but, more importantly, they proved to be more effective and promoted beach expansion. However, these works benefited beaches in areas where tourism is more developed at the expense of other sectors. This triggered requests to extend the artificial reef to the entire gulf, especially its eastern side, where tourism growth was favored by the decline of industrial activity. Several beach nourishments were carried out in the last ten years, including the use of gravel (approximately 50,000 m³), particularly in locations where submerged groins were built (Figure 23).

Similarly to Marina di Pisa, urban development began when beach erosion, although modest, had just started. The need to protect newly built houses and bathing facilities led to the construction of hard structures that, in turn, increased erosion rates in unprotected segments of the coast. Today, the coast features three ports (with Piombino’s expanding into the gulf), 8 km of detached submerged breakwaters, 7 submerged groins (each approximately 150 m long), and 9 jetties totaling approximately 1.3 km in length. This infrastructure covers more than 50% of the beach length, contrasting with its pristine state in 1883. The eastern part of the coastal plain is subsiding at a rate of up to 1 cm per year due to water extraction for industrial and agricultural use, contributing to beach erosion [49]. Eustatic sea level rise will exacerbate relative land lowering, potentially leading to the submergence of parts of the coast. Currently, there are no strategies in place by public administrations to address this issue. Instead, plans are underway to convert the power plant, which was decommissioned in 2015, into a shopping center.

4.5. Ombrone Littoral Cell

This 21 km long beach is mainly fed by the Ombrone River, which enters the sea in its southern part, with a minor contribution from the Bruna River, which empties at Castiglione della Pescaia (Figure 1). As mentioned earlier, the Ombrone delta has formed over the last 2500 years, and in 1883, its mouth was approximately 6.5 km offshore from the Etruscan shoreline. Since then, the river mouth has retreated by more than a kilometer, a process initially accelerated by land reclamation efforts in the Grosseto plain, which diverted the river’s floods [50]. Erosion has gradually affected the adjacent beaches, extending 2.0 km to the north and 1.5 km to the south, according to the 2019 shoreline (Figure 24). Further beaches have continued their historical progradation, with sand extending 700 m in front of a cliff at the southern end of the physiographic unit (Figure 25).

Considering a beach-surface expansion of 2.7 km² in the northern sectors and 1.1 km² in the southern ones, a total accretion of 3.8 km² is obtained, which is double the 1.9 km² lost by the Ombrone delta sectors. Therefore, the overall beach surface area of the Ombrone River littoral cell increased by 1.9 km² from 1883 to 2019, demonstrating that, despite reduced sediment input, the Ombrone River continues to play a crucial role in the sedimentary balance of this physiographic unit. The entire delta is part of the Parco Regionale della Maremma, and no buildings are present near the shore, except for a private house north of the river mouth. Part of the sediment input to the lateral beaches results from erosion at the delta apex, but this process is now countered by several shore-protection structures:

• On the north side, a 120 m long detached breakwater, connected to the coast at its northern tip with a groin (similar to a pocket breakwater), has protected the aforementioned house since 2019 and now is reached by the beach (Figure 26a).
• On the south side, a riprap (built in the early 2000s and flanked inland by a levee constructed in 2014) stabilizes the shoreline and prevents saltwater intrusion into a brackish water wetland.
• Further south, six submerged geotextile groins (each 130 to 260 m in length, built in 2016) stabilize a beach that is extensively used for free bathing (Figure 26b).

Considering that this is a regional park, the two rocky protection structures must be considered even more negative, as they have an adverse impact on the landscape and, as demonstrated in other places (e.g., [51]), pose an obstacle to the deposition of loggerhead sea turtle eggs. Along the Tuscan coast, sea turtle nesting occurs in only a few places, and this is one of them.

Approximately 6.3 km north of the river mouth, at Marina di Grosseto, a tourist port was created by transforming the outlet of an artificial channel that drains the coastal plain. Before World War II, the channel mouth was equipped with two short jetties to prevent siltation from sediments moving from south to north. These structures were gradually extended and converted into harbor breakwaters in 2003, although berths are located in a dock excavated on the beach and along the channel. The updrift beach (sections 71–73, Figure 24) expanded by approximately 20 m in one year, causing siltation at the marina entrance. Consequently, a bypass was activated, dredging sand from the southern beach and marina entrance and depositing it on the northern beach, which is now maintained after initial erosion.

Approximately 20,000 m³ of sand should be bypassed annually, but the actual volume moved depends on the necessity to keep the channel mouth open (Figure 27). The potential longshore transport is approximately 30,000 m³/year [27].

At Castiglione della Pescaia, the 17th century short jetties at the mouth of the R. Bruna were progressively extended with an opening to the north to prevent siltation of the outlet. Due to wave diffraction, the structures cause a local inversion of the sediment transport, resulting in the formation of a wide beach on the right side of the river mouth (Figure 28). A similar sediment transport inversion also occurred on the southern side due to wave reflection, but this has led to beach erosion.

On the 800 m long coastal segment south of the river, second houses were built on the dune systems in the 1960s and 1970s, when the erosion process was just active (Figure 28), and soon nine 70 m long low-crest detached breakwaters with gaps of 20–40 m were constructed. Given that a wide coastal strip was undeveloped at that time, a wiser location of the buildings might have eliminated the need for shore-protection structures.

The remaining 6 km of beach to the north (sectors 1–25), at places protected by a wide beachrock at low tide level, is larger than in 1883 but still experiences modest erosion. Shore-protection structures have been proposed under pressure from beach concessionaires and local stakeholders. If implemented, they could compromise one of the few remaining natural beaches in Tuscany. Unlike the delta area, which grew rapidly with low dunes and wide interdune areas following the Psuty model [52], making it susceptible to flooding with sea level rise, this area features tall, close dunes and higher elevations that are less vulnerable to flooding even under severe storms. Given that a significant source of sediment now comes from the erosion recorded at the Ombrone River delta where no human structures are present, a critical decision must be made about whether to permit (possibly managed) erosion of the delta as proposed in a published report for the benefit of urbanized beaches [53].

5. Conclusions

This paper presents an analysis of the evolution of Tuscany shoreline juxtaposed with the concurrent development of coastal settlements and various coastal-protection techniques. For the early stages of the period analyzed (1880s), the accuracy of the shoreline position may be affected by survey and georeferencing errors, particularly in areas that were completely uninhabited. However, this information remains highly valuable as it pertains to the period immediately preceding the onset of coastal erosion and urbanization. This study illustrates how the absence of comprehensive territorial planning that considers large-scale spatial and temporal factors has led to the degradation of the environmental assets that attracted and favored the initial developments. Almost all Tuscan beaches were expanding until at least the late 19th century when the coast was still largely undeveloped. Erosion began at river mouths due to reduced sediment input, coinciding with coastal development, often in areas already affected by recent erosion processes.

Hard shoreline protections were quickly implemented in some areas to preserve beaches, but these measures invariably induced downdrift erosion, triggering a chain reaction that transformed pristine coasts into armored ones. At the onset of beach retreat, coastal development was still in its early stages, with buildings mostly consisting of wooden shacks, cabins for bathers or small unauthorized houses. Despite this, the “do nothing” or “abandonment” option was never chosen; instead, shore-protection structures were put in place to counteract coastal retreat.

Even during more severe erosion phases, urbanization continued to expand linearly along the coast to maximize profits from prime coastal positions, which soon necessitated governmental investments for their protection. The total surface area of all Tuscan beaches today exceeds that of the 1880s, largely due to sand accumulation updrift of harbors and jetties and, at a few places, behind detached breakwaters. The sediment budget of the Northern Tuscany littoral cell remains positive, although erosion affects 37.4% of the sandy coast, with 27% artificially protected. Most projects were designed to safeguard beach economies, with recent transformations of some structures into submerged ones reflecting demands for improved landscape aesthetic and water quality. Coastal transformations, from settlement development to shore protection, have predominantly been driven by local and short-term demands, lacking a long-term strategic vision. Beach nourishment often utilized nearshore fine sediments to accommodate beach concessionaires installing sun umbrellas for immediate profit, with only a few projects using coarser aggregates (which are less preferred by beachgoers) for beach stabilization.

While the rise in sea level since the industrial era has thus far played a minor role in beach erosion, future scenarios—particularly extreme but plausible ones—suggests that sea level rise may become the dominant driver of coastal erosion, compounding current factors. Additionally, many coastal areas have been reclaimed over the past centuries, with land elevations often at or below current sea level position. This will significantly transform the coastal landscape, both its natural and human-made components. Yet, political decision-makers and territorial planners still lack a coherent strategy to address these emerging challenges.

The analysis of the evolution of Tuscan beaches, which until now has been studied in separate sectors or without a broad temporal perspective, allows us to highlight recurring mistakes in both urban planning (or lack thereof) and in the protection of individual coastal stretches.

The awareness of past mistakes places greater responsibility on those who today must decide the future of these coasts, where it is no longer possible to approach the issue with a local perspective and act only in response to emergency.

The knowledge of the history of Tuscan beaches can be valuable for those countries where seaside tourism is following a trajectory similar to that of the initial phase that characterized the Tuscan coast, helping them avoid repeating the same errors. To this end, comparative studies will be necessary, taking into account the environmental and socio-economic differences of each county.