The Union of City and Sea The Evolution of Venetian Environmental Adaptability Urban History, ARCH 4330 Gina Stovall, Spring 2014
THE URBAN ECOSYSTEM; A CLIMATE CONUNDRUM Those who cannot remember the past are condemned to repeat it. -George Santayana This largely over-employed aphorism from the early 20 th century Spanish philosopher is popular for good reason. Over half of the world s inhabitants call cities home. Urban development, or urbanization, involves transitions over many indicators, including demographic, economic, and land-use changes i and has a considerably long history with the earliest urban centers dating back to antiquity. The 21 st century is experiencing the mega trend of mass urbanization, with rural areas urbanizing at speeds never before witnessed. Although the rate of todays urbanization is unprecedented, the problems encountered during early history s dense development are fundamentally the same, maybe it is time to look back for clues toward solutions. In the face of climate change, cities have been assigned to the challenge of leading in mitigation and adaptation. Urban areas are both the largest emitters of greenhouse gases when viewed as a whole, but the most efficient when examined per capita. It is this fact that motivates our present environmental conundrum. Mankind s dominance over the environment is not novel phenomena. Throughout history humanity has triumphed through feats of innovation, engineering, and organization to build societies. We have become so good at it we moved past lives of sustenance, and into eras that can produce of great art, culture, and technology. Despite progress, humankind still must face the environment in which we live. The urban environment, in particular, has a unique sensitivity to environmental climate impacts engendered by a distinct physical, social, and political constitution, which creates an immediate need for adaptation planning strategy. The International Panel on Climate Change (IPCC) in its 2014 report entitled Impacts, Adaptation, and Vulnerability stated, hazard risks in urban settlements are enhanced by the concentration of populations, economic activities, cultural amenities and built environments... ii A consequence of urban density is the intensified impact of climate due to the volume vulnerable people and their demographic diversity, the existence of many cross-sectoral infrastructure systems, and the economic dominance of urban regions iii. Given all of this knowledge, the fact that densely populated areas are not a modern invention, nor are adverse environmental affects what can be learned? Granted the climate is changing at a magnitude greater than anything seen by the eyes of a modern man, but what can be said about the role development of a city plays in current resiliency strategies? Did our ancestors who built these metropolis from the dirt-, or at times water-, up have more insight as to what determines strength? VENICE, THE ADRIATIC S BRIDE Oh Venice! Oh Venice! When thy marble walls Are level with the waters, there shall be A cry of nations o er thy sunken halls A loud lament along the sweeping sea! -Lord Byron, Ode to Venice (1819) gds2124: 2
The city of Venice rises from the waters of the Adriatic Sea, proud and dynamic, an example of innovation throughout its history. Lord Byron s crying ode eloquently expresses the wide influence Venice has in Europe, and alludes to the natural crisis it was accustomed to. Made up of 118 islands connected by canals and bridges, Venice is married to the lagoon in which it sits. The marshy waters are littered with millions of wooden piles hidden beneath the artificial islands the city is built on. Even though the Doge would wed Venice to the sea on Ascension Day every year, this marriage is comparable to that of a shotgun wedding; a forcible and urgent union borne out of necessity, and not necessarily love. The isles lagoon, from which the city grew, served as a temporary refuge from invading Germanic Huns in the 5 th century AD, Yet Venice was not developed until the 9 th century AD as a permanent settlement. Venezia (as Venice is referred to in Italian) has an aqua-culture that was engendered by the lagoon and Adriatic. Canals, the main mode of transport, weave through the classical city as streets do most other cities. Seasonal flooding called Acqua Alta, or high waters, are a product of the natural climate variability in the region and historically exerted little harm to ancient Venetians. The relationship between man and water began benign, but has swollen in modernity to a relentless struggle. Studies reveal that the city sank approximately 10cm every one hundred years until 1900 AD. After 1900 that rate doubled and Venice sank 20cm in a single century. The floating city sinks due to geologic characteristics inherent to the lagoon and land-use traditions associated with modernization. Wooden stakes supporting foundational platforms were driven into the clays below and natural sinking of the soils was the original driver for the 10cm per century lowering. But as the city developed and industrialized groundwater extraction exacerbated the subsidence of Venice. The city is presently sinking at an accelerated rate due to withdrawal of water from aquifers beneath the city, which is to fast for precipitation to recharge them. This overextension of the subsurface water table leaves voids underground that enable further gradual collapse of the topography iv. More recently, the high waters have become a major concern for the city. As global atmospheric temperatures rise due to anthropogenic greenhouse gas emissions, the oceans warm and thermally expand (and therefore rise). To make matters worse, sea ice and ice sheets in the northern Polar Regions are Traditional Venetian foundation cross section; World Monuments Fund (iv) gds2124: 3
melting, adding water volume to the oceans. This sensation manifests as mean sea level rise across the worlds oceans. The seas of the Mediterranean, including the Adriatic are experiencing the effects of this sea level rise ii. Natural flooding, natural and artificial subsidence, and man-induced higher seas is causing Venice to become inundated ten times more frequently this century than last. In 1900 AD Saint Mark s Square (the lowest lying area in the city) would flood when water levels reach 120cm above mean sea level (msl), today it only requires 100cm. Likewise, the rest of the city would flood at 140cm above msl; now 120cm will produce the same flood conditions, and more portions are being affected by flooding above 120cm iv. Map of Venice inundation locations 1900 to present; World Monuments Fund (iv) gds2124: 4
The Italian Environmental Protection Agency has measured an increase of 10cm for Venice s summer sea levels higher and 20cm higher for winter sea levels in the three-year period from 2007-2010; longer analysis shoes since the 1870s sea levels have risen about 40cm. Some of this increase can be attributed to natural climate oscillations, but the trend is amplified and will continue to increase with climate change v. Global estimates for sea level rise by 2100 vary: the IPCC forecasts global average sea level can increase from approximately a quarter of a meter to about one meter by 2100 vi. Such increases would Venice, turning it into a year round city submerged in the swampy waters of it s lagoon. To address the impending problems of higher high waters, Venice has implemented early warning flood systems and will soon unveil large-scale flood barrier, MOdulo Sperimentale Elettromeccanico also known as MOSE ii. Yet even the massive infrastructure investments to isolate the lagoon from the rising Adriatic will limit impacts for just a few decades iv. It is important here to ask, how did Venetians of the past adapt to the climate variability of the Acqua Alta they likely did not anticipate when first seeking refuge from the barbarians? THE EMERGENCE OF A GENIUS CITY "There is no more magnificent absurdity than Venice. To build a city where it is impossible to build a city is madness in itself, but to build there one of the most elegant and grandest of cities is the madness of genius." -Alexander Herzen (ca. 1850) The city of Venice was founded in 421 AD on March 25 th according to legend. Although the date is dubious, the timeline for the city s establishment is generally agreed upon. Initially under the rule of the falling Roman Empire, Venice and its neighboring mainland Venetia were absorbed into the rising Byzantine (or Eastern Roman) Empire. Prior to the invasions of Attila the Hun in the 5 th century, and as early as Roman rule fisherman inhabited the lagoon. These fishermen were referred to as referred to as incolae lacunae or lagoon dwellers. It was not until the end of the 6 th century AD that pressure from invaders pushed wealthy from the mainland province to the marshy islands of the lagoon where they could remain under Byzantine Rule vii. Since Roman times, the lagoon was experiencing a rise in sea level due to a melt in the polar ice caps viii ; melt was induced by the warmer global temperatures of the Holocene interglacial period. Native Venetians were accustomed to lunar tides and the less predictable tides determined by weather conditions in the Adriatic Sea vii. In spite of the terrain, or lack thereof, the Venetians managed to conquer the landscape. Typical Venetian foundation consisted of wooden piles hammered into the muddy silt, clay, and bedrock below the lagoon surface. On top of that is a stone able to resist erosion. Above the footings brick and stone buildings were constructed. Venetians also maintained their canals and channels by dredging them, and the resultant silt was used to form more building land. The settlers adapted to their surroundings using the unfamiliar resources they had. They evolved into a maritime people, taking advantage of fishing and merchant trade; building an equitable society on the one advantage they had, the sea. gds2124: 5
The rise of the Venetian Republic was marked when the settlements were made a military unit in 697AD under the Doge (Dux). By 810 AD the Doge relocated from Ravenna and then Malamocco in retreat from the invading Lombards prior to landing on the present day Rialtovi. The Rialto, formerly Rivo Alto, gradually developed as the heart of the Republic gaining prominence as the Byzantine Empire declined; in 810 AD it became the capital of Venice. When Rialto was first established it was substantially above high tide, whereas now it is essentially at seal levelvii. Map of Venice Lagoon; Wikipedia Commons Prior to Venice establishing it s capital, Charlemagne, the leader of the Holy Roman Empire sought to conquer them. In 809 AD Charlemagne suggested his son Pepin of Italy, king of the Lombards, take Venice. The siege lasted six months. Pepin s army could not navigate the marshland and contracted diseases, weakening his forcesvi. Venice was protected by the waters, from which it blossomed. The lagoon that accommodated the earliest Venetians, acted as their saviors once again. Shortly after Pepin withdrew he succumbed to a disease he contracted during the siege and only months following his death did Charlemagne recognize Venice as a Byzantine state. After 811 AD, when the Pax Nicephori was signed granting Venice semi-independent provincial status, Venetian merchants began to gds2124: 6
capitalize on their access to the East. As a Byzantine territory, the agreement granted Venice commerce rights to the Adriatic coast. Roman classicism was overshadowed by the extravagance for Byzantium and Venice grew more independent. In 828 AD (or 829) two Venetian merchants accompanied by two monks are said to have stolen the body of Saint Mark the Evangelist from Alexandria, Egypt. The relics were smuggled back to Venice within shipments of pork to evade Muslim customs officers, and Saint Mark became the patron saint of the city. The Basillica of San Marco (Church of Saint Mark) is one example of ornate, monumental architecture stimulated by Byzantine influence. The Church honoring the city s new patron was built in a construction similar to that of the Twelve Apostles in Constantinople vii. Life and water were one in the pre-republic city. The water enabled the city s growth to eminence, wealth and culture, but successes gained by water would lead Venice to become discontent with it. Piazza San Marco, Venice. Canaletto ca. 1730-1735 gds2124: 7
A TUMULTOUS ROMANCE There are three enemies of the lagoon: the land, the sea, and man. (Old Venetian Proverb) The construction of Saint Mark s Basillica was not conducted in ignorance of the intermittent tides. Venetians recognized the necessity of city planning, and the method of driving piles into incidental landmasses ( building land ) made up of silt and debris was concocted. By 1224 a magistrate to maintain clear channels and canals was formed. By 1501 the Magistrato all Acqua (a hydrologic engineering magistrate) was formed. The Venetians became more audacious as the city matured, diverting rivers and determining physical chemistry with dykes of the lagoon; they manufactured a custom ecosystem was built viii. By regulating silt inflows and freshwater fluxes the Venetian administrative officials began to dominate its formerly humble relationship with the lagoon. The space in front of San Marco was cleared to create the grand Piazza, while a nearby moat was filled to build the Piazzatta. During the middle ages the Venetian prowess to alter the urban form exploded, and the natural topography of the lagoon had no defense. Venice understood that the culture and economic fortitude that had been created was in delicate equilibrium with the shifty lands below it, the temperamental seas surrounding it, and the men who inhabited it. The proverb of the three enemies signifies an important shift in perception that the waters, which repeatedly served as their protector prior, were now a threat. The Piazza and Piazzetta and San Marco. debarbari ca. 1500 gds2124: 8
Rotta della Cucca (the breach at Cucca) reported by Paolo Diacono in Historia Langobardorum (translated as Paul the Deacon s History of the Lombards ) is the earliest record of flooding in the region near Venice. His account details the all the rivers emptying to the lagoon of Venice in the year 596 AD, simultaneously flooding and forever changing the lagoon s morphology: In quel tempo ci fu un diluvio nei territori della Venezia, della Liguria e di altre regioni d'italia, quale, si crede, non ci fosse più stato dai tempi di Noé. Fattorie e terreni si trasformarono in lavine e ci fu gran strage sia d'uomini che di animali, furono disfatti i sentieri e cancellate le strade; il fiume Adige si gonfiò tanto, che le sue acque giunsero a toccare le finestre superiori della chiesa del beato martire Zenone, che è posta fuori di Verona 1. -Paolo Diacono (787 AD - 796 AD) ix Paul the Deacon speaks of loss of life and livelihood. Over 600 years later, in 1240 AD the water in the streets of Venice was higher than a man. And 1600 AD is recorded as a year of frequent flooding, breaking the shores of many nearby cities and towns, including those on the protecting Lido inlet x. The Republic of Venice had a lauded reputation for egalitarianism and liberty. The circumstances by which early settlers came to the lagoon, as refugees with no property and no resource but the sea, enabled Venice s democratic culture. And the freedoms granted by the Byzantines after Charlemagne s failed attempt to annex them during the city s infancy persisted in politics until the Republic s fall vii. Venice s ideal of equality and autonomy may have roused the desire to be free of its marriage to the sea; to control its own destiny and engineer its freedom, opposed to obliging the sea. IS DIVORCE IMMINENT? You own many and many a ship; your vessels fear not the stormy winds. They come home safely to port, nor do they ever founder, they who time after time set sail from shore. The famous Venetia, already rich in nobility, touches, to the south, Ravenna and the Pol to the east it enjoys the smiling shores of the Ionian Sea, where the alternate ebb and flow cover and uncover the face of land. There lie your houses, like water fowl, now on land, now on islands; and when the change comes, they are seen scattered like the Cyclades over the dace of the water- habitations not made by nature, but founded by the industry of man. For the land is made by solid wattled piles, nor do you dread to offer so fragile a bulwark to the waves of the sea when the low-lying islands fail to beat back the weight of water because they are not high enough. - Cassiodorus (ca. 523 AD) xi 1 English Translation: "At that time there was a flood in the territories of Venice, Liguria and in other regions of Italy, which, it is believed, there had been more since the days of Noah. Farms and land turned into avalanches and there was great slaughter both of men and animals, were defeated and the trails cleared the streets; the Adige river swelled so much, that its waters reached to touch the upper windows of the church of the Blessed Martyr Zenon, which is located outside of Verona." gds2124: 9
Cassiodorus, a Roman writer and statesman, aptly acknowledges Venetians mastery of the water: They come home safely to port, not do they ever founder. And yet he also recognizes their instability: For the land is made by solid wattled piles, nor do you dread to offer so fragile a bulwark to the waves of the sea when the low-lying islands fail to beat back the weight of water because they are not high enough. But with worsening and more frequent flooding, some Venetians are fearful of the flooding waters, or at least have grown tired of them vii. During the 17 th and 18 th centuries Venice experienced significant fluctuations in population; resident numbers ranged from 100,000 to 160,000 people. In 1969 population size was at 120,000 vii, but has been recorded to be below 60,000 as recently as 2012 viii. Some may attribute this to increases in touristic activity. But it seems more likely that foreboding climate change forecasts that are becoming apparent with increased flooding and rapidly degrading infrastructure would have more of an impact than increased daytime foot traffic. November 4th, 1966. Photograph of 194cm high Acqua Alta gds2124: 10
The Italian government, highly cognizant of the current and projected sea level rise impacts, has embarked on the Venice Lagoon Project. The most dramatic and controversial component of this plan is centered on the mobile barrier system MOSE, Modulo Sperimentale Elettromeccanico. The system is designed to create a gate that will join the Lido inlets to block waters from the Adriatic from entering the Venetian Lagoon during high tide events and storms iv. The apparent estrangement and love lost between Venice and its lagoon makes one wonder if the lust of the medieval development can be rekindled. Should Venice continue to resist the rising tide with gargantuan feats of engineering or is there a more cooperative way to work with the changing environment? It is possible that bending the waters to our will with massive adaptation engineering is not the way to make the relationship last. Yet if no compromise can be made between the city and the water, is a retreat in order? An effective divorce of the genius city and the lagoon that fostered it? A divorce of this type is exponentially more consequential than an ordinary divorce. The art, architecture, and culture born out of the love affair between a city and the sea is at risk at being lost. So maybe we have no choice but to continue on our path of manipulating the environment to our will in order to hold on to these invaluable treasures a little longer. i IPCC, 2014: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. ii IPCC, 2014: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. iii Rosenzweig, C., et al. (2011). Climate Change and Cities: First Assessment Report of the Urban Climate Change Research Network. Cambridge University Press, Cambridge, UK. iv Cocks, A. S. (2005). Science of Saving Venice. New York: World Monuments Fund. v Umgeisser G., et al. (2011). The Future of Venice and Its Lagoon in the Context of Global Change. Venice: United Nations Educational, Scientific and Cultural Organization (UNESCO). gds2124: 11
vi IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. vii Howard, D. (2002). The architectural history of. New Haven: Yale University Press,. viii Lane, F. C. (1973). Venice, a maritime republic. Baltimore: Johns Hopkins University Press. ix Paul. (1974). History of the Lombards. Philadelphia: University of Pennsylvania Press. x Giordani Soika, A. Supplemento al vol. XXVII del bollettino del Museo di Storia Naturale di Venezia xi Molmenti, P. (1906). Venice: Its Individual Growth from the Earliest Beginnings to the Fall of the Republic. John Murray. gds2124: 12