Remote Sensing for Science, Education, Rainer Reuter (Editor) and Natural and Cultural Heritage EARSeL, 2010 Cultural Heritage Between the Mountains and the Sea in the Eastern Adriatic Vlasta BEGOVICa, and Ivančica SCHRUNKb a Institut za arheologiju, Ul. Grada Vukovara 68, Zagreb, Croatia b University of St. Thomas, 2115 Summit Avenue, St Paul, Minnesota 55105, USA Abstract: Tectonic movements and climate change endanger historical and archaeological sites located in the coastal areas of the eastern Adriatic. Steep mountain slopes and narrow coastal lines with many bays and promontories dominate the topography of the region. These were advanta- geous for human habitation and construction in the past, but today represent a dangerous location between the mountains and the sea. Only within the last few months there have been several very dangerous flash floods and inundations in this region. In November 2009, flash flood and high winds damaged the historic urban cores of Dubrovnik and Pula. In December 2009 sea flood af- fected the central Dalmatian coast and the islands. Later in December, torrential rain (110 litres per m2) caused flash flood and tidal waves up to one metre high, which flooded Rijeka (ancient Tar- satica). A waterspout brought destruction to central Dalmatia. In January 2010, the river Neretva and its tributary Norin flooded and endangered the ancient site of Narona (Vid near Metković) in the delta. The cause was the melting of snow in the Dinaric mountain range, an unusual event in January. The same cause triggered floods of the rivers Krka, Vrlika and Lika in the northern Dal- matia, where the water level rose 0,5-1 m per day. The ancient settlement of Scardona on the river Krka was threatened. At the beginning of March high north wind reached the speed of up to 120 km/hour In the middle of May it was another big storm with 50 litres on square metre and very strong wind. The sea level in the eastern Adriatic has risen about 2 m since antiquity due to the movement of the tectonic plates – the Eurasian plate and the European micro-plate, which meet in the middle of the Adriatic. The rising of the sea level could be measured on the sites of Roman maritime villas, whose structures (porticoes with exedras, harbours, fish ponds) built on the an- cient shore are today submerged. At the site of the maritime villa by Medulin near Pula a tall and long wall has been built along the sea to protect fine mosaics. These natural events are threatening cultural heritage. Remote sensing techniques, such as aerial and satellite imagery are necessary to keep systematic control and detection of changes and damage in order to protect cultural sites and landscapes. Keywords: Cultural heritage, tectonic movements, soil erosion, flooding, Adriatic coast, Adria microplate, remote sensing Introduction The earliest topographic accounts of the Adriatic coast and the islands are found in the ancient Greek sources. One of them is a nautical guide of the so-called Pseudo-Skylax (Periplous, 21-24, 4th c. BC), because it is believed that his guide is based on the text of Skylax of Carianda from the 6th c. BC. The other is a travelogue of Pseudo-Skymnos (Periegesis, 413-428, late 2nd c. BC). The original was attributed to Skymnos from Chios of the early 2nd c. BC. The earliest maps are from the Roman times. The oldest is Tabula Peutingeriana (Segments IV-VI, A-C), a medieval edition of a 3rd- 4th c. AD map, probably based on still earlier maps. Descriptions of the Eastern Adriatic have been made in 6th century by Ravennatis Anonymi in his Cosmographia. The later maps are Venetian maps from the 16th and 17th century: the map of Giacomo Gastaldi from 1546 in the Vatican library, and the map of Simon Pinargenti from 1573. Pinargenti’s topographic V. Begovic & I Schrunk: Cultural Heritage Between the Mountains and the Sea in the Eastern Adriatic descriptions are contained in his book „Isole che sono da Venetia sulla Dalmatia e per tutto l'Arcipelago fino a Costantinopoli“, and the map of the Dalmatian coast from 1689 Cantelli da Vignola. We notice that the coastline in ancient sources can be slightly different from the present one. Is this a mistake or have there been changes in the coastline? Can we believe ancient geographers and maps or are their de- scriptions of the Adriatic regions the fruit of their imagination? Is it possible that the configuration of the coast has changed since antiquity? What did they really want to say about their experiences or about the shared knowledge of the ancient seafarers? Which of the data can we consider truthful and which are mere indicators of the importance of certain regions? Figure 1. The Peutinger map (Tabula Peutingeriana) from the 4th century The fact is that the configuration of the eastern Adriatic coast is undergoing millennia-long changes. Since the beginning of our era and until the present time the coast has sunk for about 2 m and the proc- ess is continuing with increasing speed. The measurements that were taken within the last 100 years at the measuring point at Trieste have amounted to a 20 cm increase. This means that the estimated annual increase of 1 mm since antiquity has doubled in the past 100 years. We wonder how soon we should correct our geographic maps. How soon should we make plans for emergency protection of the coastal regions and structures – quays, moles, harbours, breakwaters, and built shoreline? On the eastern Adriatic coast is located some of the most valuable cultural heritage of Croatia. Seven of those sites are World Heritage Sites and six of them are on the Adriatic coast - Poreč (Episco- pal complex of the Euphrasian Basilica), Šibenik (The Catedral of St. James), Split (Diocletian’s palace), Trogir (historic city), Dubrovnik (old city), Starigradsko polje on the island of Hvar (system of Greek land division). Beside these six major sites there are many ancient urban centres: Pola, Tarsatica, Vol- cera, Senia, Iader, Salona, Pharos, Narona, Epidaurum. Others are maritime Roman villas: Katoro near Umag; Sorna and Loron by Poreč; Barbariga, Brijuni, Val Bandon, Banjole and Vižula in the area of Pula; Diklo and Petrčani near Zadar; Sreser Bay on the peninsula of Pelješac; Polače on the island of Mljet; Tiha Bay by Cavtat, and many others. Many of the coastal cities are also valuable medieval cen- tres: Poreč, Pula, Rijeka, Senj, Zadar, Biograd, Split, and Dubrovnik. The coastal heritage structures are threatened by the rising sea level, but also by unpredictable torrential rains and flash floods, and by high winds and sea floods of large areas. We shall soon see what happened on the eastern Adriatic coast in the short period from the time of the submission of 20 V. Begovic & I Schrunk: Cultural Heritage Between the Mountains and the Sea in the Eastern Adriatic this paper in the fall of 2009 until this spring of 2010. But first, we should provide a short geo- graphic overview of the region. 1. Short description of the Eastern Adriatic coast of Croatia The eastern Adriatic coast, which is for the most part within Croatia, extends in the northwester to southeastern direction. It covers 510 nautical miles of the sea, 1,777.7 km of the coast and 4,012.4 km of the islands’ coast. The entire country of Croatia extends over 56,538 sq. km of land and 33,200 sq. km of internal and territorial sea. The total length of the Adriatic seaboard is 5,790.1 km. The number of islands and islets in the eastern Adriatic is 1246. Starting in the north, at the Bay of Savudrija on the border with Slovenia, the coastal lowlands of the Istrian peninsula extend north-to-south to the southernmost promontory of Premantura. The sea depth in the northern Adriatic is less than 50 m. The western coast of Istria is low and flat. Two sig- nificant ancient cities, Parentium and Pola (today Poreč and Pula) and the medieval cities of Umag, Rovinj and Vrsar are located here. The rivers Dragonja, Mirna and Raša flow from the central moun- tain ranges into the Adriatic. The southeastern coast of Istria is mountainous and the coastal settle- ments are situated on the steep slopes: Rasa, Labin, Mošćenice, Lovran and Opatija. The highest top is Učka at 1,394 m above sea level. The river Raša was the Roman border between the land of the Histri and that of the Liburni. Sometime between the year 18 and 12 BC, Augustus extended the terri- tory of Italy proper to this border. The mostly mountainous coast continues from the city of Rijeka (ancient Tarsatica) southward. Cit- ies and villages are located on steep slopes or at the base of the mountain ranges of Velika and Mala Kapela. Others are on hilly peninsulas: Bakar (ancient Volcera), Crikvenica (ancient Ad Turres), Novi Vinodolski near Senj (ancient Senia). The highest peak is Risnjak at 1,528 m. From Senj to Starigrad Paklenica (ancient Argyruntum), the coast is very steep under the mountain of Velebit, whose peaks of Mali Ranjac and Vaganski Vrh are at 1,699 m and 1,757 m respectively. The coastal plain called Ravni Kotari, starts at the town of Obrovac. The most significant ancient city of this region was Iader (today Zadar, still the regional centre). The coast is hilly and steeper again from the city of Šibenik southward to the ancient city of Salona (Solin today) and the nearby medieval city of Split, built inside and around Diocletian’s palace. The highest peak is Klis at 1339 m.