Sometimes in a brutal winter night you may hear the distant roar of the Adriatic, pounding against the foreshore: and as you huddle beneath your bedclothes it may strike you suddenly how lonely a city Venice remains, how isolated among her waters, how forbiddingly surrounded by mud-banks, shallows and unfrequented reedy places. She is no longer a true island, and the comfortable mainland is only a couple of miles from your back door: but she still stands alone among the seaweed, as she did when the first Byzantine envoys wondered at her gimcrack settlements, fourteen centuries ago. Time and again in Venice you will glance along some narrow slatternly canal, down a canyon of cramped houses, or through the pillars of a grey arcade, and see before you beneath a bridge a tossing green square of open water: it is the lagoon, which stands at the end of every Venetian thoroughfare like a slab of queer wet countryside.
Several sheltered spaces of water, part sea, part lake, part estuary, line the north-western shores of the Adriatic: in one Aquileia was built, in another Ravenna, in a third Comacchio, in a fourth Venice herself. They were known to the ancients as the Seven Seas, and they were created in the first place by the slow action of rivers. Into this cranny of the Mediterranean flows the River Po, most generous of rivers, which rises on the borders of France, marches across the breadth of Italy, and enters the sea in a web of rivulets and marshes. Other famous streams tumble down from the Alpine escarpment, losing pace and fury as they come, until at last they sprawl sluggishly towards the sea in wide stone beds: the Brenta, which rolls elegantly through Padua out of the Tyrol; the Piave, which rises on the borders of Austria, and meanders down through Cadore and the delectable Belluno country; the Sile, which is the river of Treviso; the Adige, which is the river of Verona; the Ticino, the Oglio, the Adda, the Mincio, the Livenza, the Isonzo and the Tagliamento. This congregation of waters, sliding towards the sea, has made the coastline a series of estuaries, interlinked or overlapping: and three rivers in particular, the Piave, the Brenta and the Sile, created the Venetian lagoon. If you look very hard to the north, to the high Alpine valleys in the far distance, lost among the ridges and snow peaks, then you will be looking towards the ultimate origins of Venice.
When a river pours out of a mountain, or crosses its own alluvial plain, it brings with it an unseen cargo of rubble: sand, mud, silt, stones and all the miscellaneous bric-à-brac of nature, from broken tree-trunks to the infinitesimal shells of water-creatures. If the geological conditions are right, when its water eventually meets the seas, some of this material, buffeted between fresh water flowing one way and salt water pushing the other, gives up the struggle and settles on the bottom, forming a bar. The river forces its way past these exhausted sediments, the sea swirls around them, more silt is added to them, and presently they become islands of the estuary, such as litter the delta of the Nile, and lie sun-baked and turtle-haunted around that other Venice, the southernmost village of the Mississippi.
Such barriers were erected, aeons ago, by the Brenta, the Piave and the Sile, when they met the currents of the Adriatic (which, as it happens, sweep in a circular motion around this northern gulf). They were long lonely strips of sand and gravel, which presently sprouted grass, sea-anemones and pine trees, and became proper islands. Behind them, over the centuries, a great pond settled, chequered with currents and counter-currents, a mixture of salt and fresh, an equilibrium of floods: and among the water other islands appeared, either high ground that had not been swamped, or accumulations of silt. This damp expanse, speckled with islets, clogged with mud-banks and half-drowned fields, protected from the sea by its narrow strands – this place of beautiful desolation is the Venetian lagoon. It is thirty-five miles long and never more than seven miles wide, and it covers an area, so the most confident experts decree, of 210 square miles. It is roughly crescent-shaped, and forms the rounded north-western corner of the Adriatic, where Italy swings eastward towards Trieste and Croatia. Its peers among the Seven Seas have long since lost their eminence – the lagoon of Ravenna silted up, the lagoon of Aquileia forgotten: but the lagoon of Venice grows livelier every year.
Very early in their history, soon after they had settled on their islands and established their infant State, the Venetians began to improve upon their bleak environment. It was a precarious refuge for them. The sea was always threatening to break in, especially when they had weakened the barrier islands by chopping down the pine forests. The silt was always threatening to clog the entire lagoon, turning it into a vulnerable stretch of land. The Venetians therefore buttressed their mud-banks, first with palisades of wood and rubble, later with tremendous stone walls: and more fundamentally, they deliberately altered the geography of the lagoon. Until historical times seven openings between the bars – now called lidi – connected it with the open sea, allowing the river water to leave, and the Adriatic tides to ebb and flow inside. The Venetians eliminated some of these gaps, leaving only three entrances or porti through which the various waters could leave or enter. This strengthened the line of the lidi, deepened the remaining breaches, and increased the scouring force of the tide.
They also, in a series of tremendous engineering works, diverted the Brenta, the Sile, the Piave and the most northerly stream of the Po, driving them through canals outside the confines of the lagoon, and allowing only a trickle of the Brenta to continue its normal flow. The lagoon became predominantly salt water, greatly reducing (so the contemporary savants thought) the ever-present menace of malaria. The entry of silt with the rivers was virtually stopped: and this was opportune, for already half the lagoon townships were congealed in mud, and some had been entirely obliterated.
Thus the lagoon is partly an artificial phenomenon; but although it often looks colourless and monotonous, a doleful mud-infested mere, it is rich in all kinds of marine life. Its infusions of salt and fresh water breed organisms luxuriantly, so that the bottoms of boats are quickly fouled with tiny weeds and limpets, and the underneaths of palaces sprout water-foliage. The lagoon is also remarkable for its biological variety. Each porto governs its own small junction of rivulets, with its own watershed: and wherever the tides meet, flowing through their respective entrances, there is a recognizable bump in the floor of the lagoon, dividing it into three distinct regions.
It is also split into two parts, traditionally called the Dead and the Live Lagoon, by the limit of the tides. In all these separate sections the fauna and flora vary, making this a kind of Kew Gardens among waters; it used to be said that even the colour of the currents varied, ranging from yellow in the north by way of azure, red and green to purple in the extreme south.
In the seaward part, where the tides run powerfully and the water is almost entirely salt, all the sea-things live and flourish, the mud-banks are bare and glutinous and the channels rich in Adriatic fish. Farther from the sea, or tucked away from its flow, other organisms thrive: beings of the marshes, sea-lavenders, grasses and tamarisks, swamp-creatures in semi-stagnant pools, duck and other birds of the reeds. There are innumerable oysters in these waters, and crustaceans of many and obscure varieties, from the sea-locust to the thumb-nail shrimp; and sometimes a poor flying-fish, leaping in exaltation across the surf, enters the lagoon in error and is trapped, like a spent sunbeam, in some muddy recess among the fens.
A special race of men, too, has been evolved to live in this place: descended partly from the pre-Venetian fishing communities, and partly from Venetians who lingered in the wastes when the centre of national momentum had moved to the Rialto. They are the fittest who have survived, for this has often been a sick lagoon, plagued with malaria, thick and unwholesome vapours, periodically swept by epidemics of cholera and eastern disease, like the rest of the fauna, the people vary greatly from part to part, according to their way of life, their past, their degree of sophistication, their parochial environment. Inshore they are marsh-people, who tend salt-pans, fish among grasses, and do some peripheral agriculture. Farther out they can still be farmers or horticulturists, if they live in the right kind of island; but they are more likely to be salt-water fishermen, either taking their big boats to sea, or hunting crabs, molluscs and sardines among the mud-banks of the outer lagoon.
Their dialect varies, from island to island. Their manners instantly reflect their background, harsh or gentle. They even look different, the men of Burano (for instance) tousled and knobbly, the men of Chioggia traditionally Giorgionesque. The lagoon islands were much more independent in the days before steam and motors, with their own thriving local governments, their own proud piazzas, their own marble columns and lions of St Mark: and each retains some of its old pride still, and is distinctly annoyed if you confuse it with any neighbouring islet. ‘Burano!’ the man from Murano will exclaim. ‘It’s an island of savages!’ – but only two miles of shallow water separates the one from the other.
The lagoon is never complacent. Not only do the tides scour it twice a day, the ships navigate it, the winds sweep it coldly and the speed-boats of the Venetian playboys scud across its surface in clouds of showy spray: it also needs incessant engineering, to keep its bulwarks from collapsing or its channels silting up. The Magistracy of the Waters is never idle in the lagoon. Its surveyors, engineers and watermen are always on the watch, perennially patching sea-walls and replacing palisades. Its dredgers clank the months away in the big shipping channels, looming through the morning mist like aged and arthritic elephants. The survival of Venice depends upon two contradictory precautions, forming themselves an allegory of the lagoon: one keeps the sea out; the other, the land. If the barrier of the outer islands were broken, Venice would be drowned. If the lagoon were silted up, her canals would be dammed with mud and ooze, her port would die, her drains would fester and stink from Trieste to Turin (it is no accident that the romantic fatalists, foreseeing a variety of dramatic ends for the Serenissima, have never had the heart to suggest this one).
So when you hear that beating of the surf, whipped up by the edges of a bora, go to sleep again by all means, but remember that Venice still lives like a diver in his suit, dependent upon the man with the pump above, and pressed all about, from goggles to lead-weighted boots, by the jealous swirl of the waters.