Nature | Venice: I am not making this up

The power of the Po

August 27, 2009 9 Comments

“Every river is compelled to flow toward the sea, and it also carries tears with it.”

I don’t know who wrote that, but it is the perfect epigraph for the Po River. And nearly 60 years ago, there were many, many tears.

Those two words — Po River — are tremendously evocative to millions, especially those living near it, or in some way depending on it. It’s the longest river in Italy, and although it isn’t much compared to the Nile or the Congo, it is Italy’s mythic mass of water.

The Po valley comprises some of the richest and most heavily cultivated land in Europe.

The Po flows 405 miles [652 kilometers] from Monviso, a dazzling mountain in the Cottian Alps, to the Adriatic, through the core of the north Italian Padania Plain and drains an area of 28,946 square miles [74,970 square kilometers].

Some people think it’s monotonous and boring, but that’s when it’s just rolling along like Ol’ Man River. Then every once in a while it floods, and turns into something cataclysmic, and suddenly people are praying to God to make it boring again. You can read more in the article I wrote for National Geographic in the May, 2002 issue.

I’m talking about all this because of my chronic curiosity about a statue stuck off by itself amid a few trees near the Giardini vaporetto stop.

It’s dramatic yet curiously detached; nevertheless, you realize something serious is underway. A rescue, obviously, but it isn’t immediately clear what the danger is. It’s the Po.

Catastrophic floods have occurred many times, but in November of 1951 there was a confluence of factors which spelled doom for man, beast, buildings, crops, bridges, soil, and anything else that was in, on, or near the river. People seem to get all worked up about high tide in Venice, but that’s a Gilbert and Sullivan ditty compared to the Wagnerian devastation the Po visited on 200,000 people, nearly 1,000 of whom lost their lives.

I’m not going to try to describe it; the numbers can do it for me. But I do remember what a friend of mine in Cremona told me about the Po in the major flood of 2000: “The river under the bridge sounded like a waterfall.” In 1951, the volume of water was measured at Cremona at 399,055 cubic feet per second [11,300 cubic meters per second] — it must have sounded like the Last Judgment.

That autumn was especially rainy, not only in Italy but elsewhere in Europe and also in the United States. From November 7-13, two weather fronts — one from the Atlantic, the other from Africa — brought rain that wasn’t particularly intense, but it was continuous. In fact, due to the nature and extent of the catchment basin, it’s long rains, rather than intense ones, that create serious floods.

Before long, the ground was saturated, unable to absorb any more water. Then the rain intensified. A hot southeast wind hit the snow that was falling in the Alps, and melted it. More water.

In the five days between November 8-12, 600 billion cubic feet [17 billion cubic meters] of water fell on the Po Plain, the amount which would normally fall in six months.

The Po’s average discharge is 48,400 cubic feet per second [1,370 cubic meters]; at its flood peak in 1951, the Po’s discharge was estimated at almost ten times that, or 424,000 cubic feet [12,000 cubit meters] per second. That would be Niagara Falls doubled, thundering horizontally toward the sea.

The river was rising because many of its 141 tributaries were also rising, obviously. But when some of these smaller rivers tried to empty into the Po, the power of its flow actually forced them back, where they began to flood their own immediate surrounding territory. That southeast wind wasn’t merely melting snow, it was preventing the Po from emptying into the sea.

Nov. 13: During the night, the church bells in Casalmaggiore (Cremona) and Sabbioneta (Mantova) and all the bells in the surrounding towns and villages begin to ring, to summon the men to try to block the rising water. Urgent requests go out for sandbags.

Nov. 14: The Po exceeds 14 feet [4.30 meters]. At 7:00 pm the river bursts its embankments at Paviole di Canaro. An hour later, it breaks through at Bosco and Malcantone at the rate of 211,883 cubic feet [6,000 cubic meters] of water per second. In a few hours 156 square miles [404 square kilometers] are flooded.

When the flood crest reaches the Po Delta, the area also called Polesine, the level is higher at Rovigo — 15.7 feet [4.8 meters] — than any recorded flood ever.

Nov. 15: An emergency truck evacuating people is caught by the water at Frassinelle Polesine; 84 people, including women and children, die in what is remembered as the “death lorry.”

At 2:00 pm the river bursts the banks at Arqua’ Polesine and the water spreads toward Adria.

Nov. 18: Rovigo is evacuated.

Nov. 19: Adria, Cavarzere, Loreo are completely flooded. The cities are evacuated.

Nov. 20: The embankments at Ceserolo are cut to save Rovigo.

Nov. 25: The crest reaches the sea, and the water begins to recede. After three months, toward the end of February, only about one third of the flooded land is still submerged.

In all, some 425 square miles [1,100 square kilometers] were flooded.

The rescue efforts were massive: The Army, Navy, Air Force, firemen, police, Red Cross, Scouts, and volunteers descended on the stricken towns, working continuously with the help of some 2,000 boatmen. People spent days trapped on the roofs of their isolated houses, hoping someone would come by.

The damage in Polesine: 900 houses destroyed, 300 houses damaged, 38 communities flooded, 160,000 people forced to evacuate, 113,000 hectares of farmland flooded, and 300 hectares of land covered by a layer of sand 6 feet [2 meters] deep.

4500 cattle, 150 horses, 7800 pigs, 700 sheep and goats, and one million quintals [220 million pounds] of fodder, all lost.

37 miles [60 kilometers] of embankments and 52 bridges destroyed.

Of course no one had insurance. What was lost was gone forever. It was Biblical.

Contributions poured — excuse the expression — in, from 65 countries, including Uruguay, Tunisia, Haiti, Indonesia, Lebanon, Costa Rica, Somaliland (as it was known), and Albania, as well as NATO.

Lino remembers the effect it had on people in Venice who, like people for miles around, responded by bringing mattresses, clothes, shoes, blankets, and more to collection points around the city. My friend Roberto, from Milan, was just a tyke at the time, but he still remembers his mother telling him he had to donate one of his toys to the children in Polesine, and not just any toy. She decreed, “Your favorite toy.'”

“It was my favorite teddy bear,” he told me, “but I sent it away.”

"To the soldiers of land and sea TKTK" and below it, "To the memory of Alberto Vio, symbol of the generous impulse of Venice for the brothers of Polesine." — "To the soldiers of land and sea Venice salutes the Italians" and below it, "To the memory of Alberto Vio, symbol of the generous impulse of Venice for the brothers of Polesine." On the right side of the pedestal is incised MARZO MDCCCLXXXV and below it, NOVEMBRE MCMLI. The plot thickens.

Many improvements were attempted to prevent anything like this happening again. One of the measures taken was to build ever higher embankments, often (in the cities) walled with concrete. You know how water behaves when it’s forced into a tighter channel or tube? Think of turning on your faucet very hard. Yes. That’s what the Po does now when it floods.

Therefore, when the river floods in spring (melting snow) or autumn (rains), as it will do until snow and rain cease from the earth, it inevitably gains force as it races seaward.

So floods continue — not much anyone can do about that — but the effects are still, if not as catastrophic as in 1951, expensive and distressing. Because houses and fields and poplar forests planted for cellulose keep increasing, and always closer to the river’s edge.

Oh, and some 30 million cubic yards of sand and gravel are illegally dug out of the riverbed for construction every year. Not good if you were looking for ways to minimize flooding, which if you’re a gravel-robber you probably aren’t.

In 1994, the Po flood caused 70 deaths and 10,000 people lost their homes, due mainly to failures in the flood warning system. The human element — always the wild card.

In 2000, the Po flood caused 25 deaths and 40,000 were evacuated.

And so it goes. The Po. Majestic. Magnificent. But I’d never call it monotonous.

NOTE: About the statue with the double inscription: Everyone but me will already have figured it out — it was originally made to commemorate the heroic efforts of the Army to help the victims of the Po flood in the spring of 1882. (I know that the inscription reads 1885, but I am trusting my source, the immortal Giulio Lorenzetti, for this information.) After the inundation of 1951, the statue was recycled to commemorate the equally heroic rescue work (hence the noticeably non-1951 garb of the figures depicted).

Alberto Vio, Lino tells me, was “famous” for having provided boats for the rescue efforts. I don’t know any more than that just now, but it explains why he is mentioned on the plinth. I can tell you, though, that the statue was made by Augusto Benvenuti in 1885, and that it used to stand in Campo San Biagio, the small area in front of the Naval Museum and church of San Biagio. Lino remembers seeing it there when he was a lad. Then someone decided it should move out and they found this anonymous little spot for it by the Giardini. Kind of a modest end to a work that was entitled “Monument to the Italian Army.” But if everybody’s fine with this, so am I.

History, Nature, Problems, Venetian-ness, Water

Watermarks: The sign of “C”

August 13, 2009 3 Comments

It may be that your eye is not drawn wallward as you stroll along the canals of Venice when the tide is low.

Perhaps you don’t find the mats of squishy green clinging to the building foundations very appealing. Perhaps you don’t wish to notice how many small life forms are scurrying around, unhindered by that pesky water. Perhaps there is a general sort of sliminess that reminds you uncomfortably of just how biological the Venetian environment is, and how little the lagoon cares about posing for you and your romantic photographs.

But let’s say those things don’t bother you; let’s say you’re curious to find out what’s beneath the waterline, or almost. If you look carefully, you may very well see this:

This incised capital C with the line beneath it is called the “Comune Marino” (hence the “C”), which roughly means “average sea.” Or perhaps “sea average.” This one, as it happens, is in the canal just outside our little hovel.

Water level measurements were formalized in Venice in 1440 when the Water Authority (Magistrato alle Acque) began to measure the upper level of wet algae on canal embankments by carving the letter “C,” which indicated the normal high-tide level. Water fosters certain kinds of algae which flourish in an “intertidal zone”, which is alternately wet and dry, and the line of algae corresponds to the level of water. Obviously.

So “Comune Marino” refers to the line created by the algae, a line which clearly indicates the upper limit of the tide.

Good to know, but why? Because there are many situations in which an engineer would want to know where the average upper limit would be — if he was planning to build a bridge nearby, for example, or even an entire building.

So far, so general. Keep in mind, though, that in each place the “C” is a marker of the average sea level in that canal at that point. Its height only matters in relation to what’s next to it — the water level will be “high” (or low) compared to a building foundation or embankment. If the “C” appears to be going down (or the algae to be going up, like elevators in a French farce) it might indicate that the building is subsiding, or even that the canal is silting up and becoming shallower. Factors such as these all bear some influence on where the average sea level will be in that place and whether you find it innocuous or annoying.

A look at the mark when the tide is out. This illustrates the difficulty of answering the frequent question, "How deep are the canals?" As in, when the tide is high, or when it's low?

An analysis of the displacement of the “algal belt” also gives engineers some idea of the long-term trend of apparent rising of the sea level. This is a subject that is far too great for this little post, but I merely note that the algae is playing its part in informing the world about the state of Venice.

Don’t be too quick, though, to think that just because there’s some algae above the “C” that the city is sinking inexorably into the lagoon. The algae has its own growing period (late winter to early autumn) and if the average high-tide level should rise one year, for one or many of several reasons, the line of algae will also rise. If it should go down the next year, there will be less algae at the previous level. Exceptional peaks in the high-tide level may cause temporary new growth, but it won’t necessarily survive the sunshine and dryness that returns when the tide level goes down.

Algae growth is also influenced by whether its location is on a sunny or shady side of the building, or whether the stone or brick it’s inhabiting is particularly porous.

Field observations have shown that the fluctuation in the height of the “algal front” is no more than 2 cm (7/10ths of an inch).

So all is well? Not really. One factor the Venetian engineers of 1440 didn’t have to deal with was “motondoso” — that’s a polite way of saying “water constantly splattering from the waves caused by motorboats.”

I’ll be devoting plenty of attention to motondoso on a future page, but I recommend that you draw conclusions very carefully about water level based solely on the line of algae. It’s highly likely that whatever spot you’re looking at is getting drenched by waves day and night, encouraging algae in an extravagant way, something that wasn’t happening back when they were busy carving “C’s” all over town.

The constant and extreme "motondoso" in the Giudecca Canal has created the perfect environment for algae on what used to be considered dry land. Do not ever step on this kind of algae, it's more slippery than a slice of raw bacon. — The constant and extreme "motondoso" in the Giudecca Canal has created the perfect environment for algae on what used to be considered dry land, so its presence here doesn't tell you anything useful about average sea level. Do not ever step on this kind of algae, it's more slippery than a slice of raw bacon.

The Daily Trivia: Regular measurements with instruments began in the 1870s. In 2004, mean sea level was found to be 25 cm (9 inches) higher than it was in 1897. Yet all water-level measurements continue to be based on the mean sea level in 1897.

We like to cling to the old ways here. Or something.

Food, Nature, Venetian-ness

The voyage of the seppia

May 19, 2009 3 Comments

This morning we were walking along the fondamenta across the canal from our hovel, and my eye fell upon one of the boats tied up alongside.

It takes no time at all to reconstruct the scene: A seagull nabbed a seppia, or cuttlefish, and a battle ensued, which the seppia lost. You can tell by the splashings of desperate black ink. Another clue is the cuttlebone, which if I had a parakeet or Andean condor I would immediately have taken.

Your cuttlefish are no match for a seagull’s beak, as you see, but don’t underestimate them. If you were a small marine creature you’d want to do everything possible to avoid any passing seppia (plural: seppie; in Venetian sepa/sepe). Soft and squidgy they may be (although technically a mollusc), but they too have a sort of beak, and it’s tiny and hooked and sharp. They look so innocuous, sort of like Mister Magoo, as they drift fecklessly along, but just remember that they have that mouth. Not much use in land combat, though. I could tell you some stories about that sharp little beak, and I probably will, at some point, but I don’t want to ruin your enjoyment at thinking of how delectable they are, so I’ll stop. The little ones are wonderful grilled. They are a classic Venetian snack, or cicheto (chih-KEH-to). The bigger ones are chopped up and simmered in water and tomato paste, and their ink. Some people omit the ink, which is heathen.

While we’re talking about their being eaten, by whatever sort of life form, make a note that seppie (on spaghetti or in risotto) are the only fish on which you are allowed to put grated parmesan cheese. To see someone put cheese on any other fish dish makes Venetians shudder. But it is, in fact, required on seppia. If you don’t try this, you won’t know what I mean. Trust me. If your waiter tells you not to do it, ask him where he’s from. Or just smile and go ahead anyway. Or skip the smile.

Another seppia clue: If you walk along the fondamentas edging major channels — say, along the Riva dei Sette Martiri in Castello, or the Zattere in Dorsoduro, or the opposite side of the Giudecca Canal, on the Giudecca — you will certainly see stains like these on the stones. Now you know they’re not paint. Many of them indicate epic battles, all futile.

There are two seppia seasons: Spring, which is when they come into the lagoon from winter quarters somewhere in the Adriatic in order to spawn, and anytime after the festa del Redentore (third Sunday in July), when the fraima (fra-EE-ma) begins, the general ichthyous exodus from the lagoon out to sea. This second period is, obviously, the time when you are aiming for the little ones — I hate calling them babies, but that’s what they are. In both of these periods the deepest lagoon channels are strewn with temporarily anchored boats from which men, and often their wives, too, are fishing for seppie. These boats refuse to move for any passing craft, from the vaporettos to the cruise ships. It drives the captains to the verge of crazy.

And speaking of decoding cuttlefish, I saw my first seppia this year on March 6. It wasn’t the little cephalopod itself, but its remains, floating in with the tide in the canal outside our hovel. It made me so happy I took a picture of it — it was like seeing the first [crocus, sandhill crane, or add your favorite seasonal thing here].

Then the fondamentas begin to fill up, lined with amateur fishermen, some of whom take their catch home, and some who sell it. They often go out at night, too, depending on the tides, rigging up a strong light to attract the animals. Or they use a fish-like lure. Lino once slew a vast number of them by hooking a medium-length remnant of a white plastic bag to his line and pulling it slowly through the water; despite the fact that seppie have some of the most developed eyes in the animal kingdom, it somehow looked irresistibly like another seppia. They don’t eat only crabs, shrimp, worms, or whatever — they snack on each other, as well. Too much information?

But we’ve caught seppie without even trying, when we’ve been out rowing, minding our own business. There one will be, just floating along; if it’s close enough to the surface you can pick it up with your hands. It’s better, though, to have a volega (VOH-ehga), the net on the long pole, because you can go deeper. If you can see it, you can probably catch it. I used to feel sorry for them; Lino’d be all excited and I’d be shouting, “Dive, little seppia, dive!” He thought I’d lost my mind. Now that I know how good they are, I’ve quit that. There will always be more. It’s not like they have names.

Last tidbit for the day: In the fish market, they used to use seppia ink to write the prices on pieces of paper. (Hence the color tone called “sepia,” which is more brown than black, really, but which came from the cuttlefish’s ink.) There must have been generations of fishmongers with permanently black hands. Just as soon as the Sharpie and Magic Marker were born, and tourists began to pay good money to eat spaghetti with cuttlefish ink, you can believe that stopped.

One more thing: It may not be very likely that you’ll be buying seppie in the fishmarket, but if you are looking at them for whatever reason, you should know that the whiter they are (it’s more like a ghastly gray mortuary pallor), and the more smeared with sticky black ink, the older they are. Lots of ink is a Bad Sign.

The super-fresh ones, as shown here, have very little ink on them, are a lovely brown with faint pale stripes, and display the most amazing iridescent stripe along their bodies, which is another guaranteed way to confirm their freshness. This stripe is made up of iridophores, which reflect the color of the seppia’s immediate surroundings and hence are part of its system of camouflage. I did not make that up.

Boatworld, Nature

May Day in Venice: What we did

May 5, 2009 No Comments

We ran away. We ran far, far away, out into the lagoon in a little three-oar sandolo called “Granchio” (crab) with our best friend Anzhelika.

By “running,” I mean rowing, naturally. We left the Lido about 8:00 and rowed all the way to Quarto d’Altino, on the mainland shore out beyond the airport. We got back around 6:00; it’s about 45 miles roundtrip, and we were going against the tide. Both ways. And there were also waves, in the sense that after a typhoon you might say there had been wind. I woke up the next morning feeling as if a battalion of small people with big hammers had been pounding me all night.

We’ve done this before, with various people on various types of boat, and it’s always wonderful. The reason is simply because we go out into a distant, seemingly wild part of the lagoon which is so different from the area we’re used to, near the city. We wend our way through the barene, or marshy islets, and along reed-lined channels that seem luxuriously remote (if you can ignore the sound of airplanes taking off from Marco Polo airport just a mile or two away).

This is something like what the lagoon looked like, in a broad sense, to the earliest Venetians who took refuge here from the passage of Attila and his Huns. (I say “broad sense” because most of the barene that formed much of the lagoon landscape even 50 years ago have been washed away by the motondoso, or waves from motorboats.) We had to face our share of motorboats, but what mattered was the haunting loveliness of the waterways.

As we rowed easily along (in the stretches without motorboats), listening to the musical soft sound of our oars and the answering music of the water sliding under the boat, we could also hear the crooning of turtledoves, and a few nightingales, and a distant cuckoo, which sings only in May. There were gleaming white egrets, and one stately heron that flew heavily away. The hawthorn trees were lush with clusters of creamy blossoms, and I could see some tangly bushes of pink wild roses. The surface of the water was streaked with the faint but clear wake of scattering fish, usually grey mullet, and once or twice one sprang into the air, attempting something resembling the long jump. When the breeze shifted, or the clouds let more sunshine through, the wetlands would give off a faint muddy smell which seemed oddly clean. There was a hawk wandering around overhead. And a pair of swans, not far from the fish-farms.

All of this, and much more which I haven’t yet seen, or didn’t know when I saw it, is — of course — under phenomenal pressure from all sorts of human activities. The most dangerous and, for us, the most maddening, and even painful, were the motorboats. Big honking mothers full of trippers from somewhere back in the countryside, or smaller boats roaring past with teenage boys, or even cruddy little old boats with cruddy motors carrying some sort of decrepit men with old fishing tackle.

We stopped for half an hour at the trattoria “Ai Cacciatori” at Mazzorbo, just before Burano, for the usual sopressa sandwich and plenty of water. Lino, naturally, had an ombra, a glass of white wine. Venetians call this morning refresher (or afternoon, or evening…) a “shadow.” The story goes that back in the very olden days, when the Piazza San Marco was something between a Levantine souk and the Roman Forum, there was a man who sold wine from a small stand in the shadow of the belltower. As the sun moved, he would shift with it to stay in the shadow, and so people went from saying “Let’s go have some wine in the shadow” to just suggesting, “Let’s go have a shadow.” That’s the story, which I have no plans to research further.

We got to Altino past noon, and somewhat past the time when I had begun to wish we were already there. For all the breeze, you could still feel the sun, beginning to shine back up from the water onto your face, and it was hot.

We tied up the boat in the reedy little canal that ends at the very old pumping station; there are still fields stretching out here that need to be irrigated, or drained. Altino was an important Roman town on the main road heading northeast, and farmers still turn up assorted Roman relics of metal or marble. We had lunch at the trattoria “Antica Altino”and started the row home around 3:00.

It was about the time we were passing Sant’ Erasmo that I began to feel really tired. Being tired doesn’t impress me, but I wasn’t happy because I knew what was coming up, and it would have been so much better if I hadn’t been tired: Traversing the lagoon between the island of the Certosa and the vaporetto stop on the Lido at Santa Maria Elisabetta. If I were to say “Recreating Lawrence of Arabia’s life-threatening trek across the Sun’s Anvil,” or “Sailing around Cape Horn with only a torn jib and a busted rudder,” I’d be saying about the same thing.

Of course I knew there’d be waves, but they were worse than I had anticipated, caused by the ferries, and the big motonave to and from Punta Sabbioni, and tourist launches, and taxis, and vaporettos, and all sorts of private motorboats. As far as the quantity of boats is concerned, this was one-quarter or less of what it will be on a Sunday afternoon in July. But it was enough for me. Big, heaving, confused waves came from all directions; small, invisible waves tried to suck the boat back out from under our feet; tall, curling waves surged toward the bow, threatening to send sheets of water into the boat; clustering waves just pounded the boat from all sides, with no design, no rhythm, no pauses. And did I mention we were also rowing against the tide? I believe I did. By the time we reached the tranquil home stretch of water, halfway along the Lido, my left knee was stabbing, my right shoulder felt like a hot anvil had been dropped on it, each palm had a stinging red blister, and I was pretty much at the blind staggers stage.

Of course we swore we’d never do this again. We may have sworn this last year as well. If we do this next year, I will undoubtedly swear it was for the last time. Does that mean it wasn’t punishing? Of course not. Next year it will be even worse. But by the next morning — about the time I became conscious of having been bludgeoned with crowbars — the black, fermenting rage that darkened the return had already faded to pale grey in my mind, and now all I really remember are the birds calling and the boatsong, and the scent of the watery land, and what a great thing it was that the old Venetians had diverted a couple of rivers, because otherwise by now we’d only have had fields and parking lots to row across.

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