This blog appears in the In-Depth Report Science at the Sochi Olympics

So, Sochi! The Olympics are about to start, you're going to see all sorts of shiny new buildings and ski slopes, and you'll be so excited by the events you may not pause to consider how they got there. You may have spent a minute or two wondering why the Winter Olympics are being held at a summer resort. I got you an answer to that, and lots more to questions you probably never thought to ask. Curiosity aroused? Let's go Sochi!

(Just don't proceed if you want your Olympics mellow harshed, because I've got some disturbing stuff along with the fascinating. M'kay?)

Right, well. Let's first find about about this summer resort business. Sochi, on the Black Sea, is a pretty mild spot, one of the few places in Russia where you can bask in a lovely subtropical climate. It's got wonderful hot summers, beautiful warm autumns, and cool but not freezing springs. In fact, it's a lot like Seattle, and lemme tell ya, we're not skiing right now. Like us, the people of Sochi have to have some good wet-weather gear this time of year. Winters are rainy! All that moisture from the Black Sea goes bang up against the Caucasus Mountains and thoroughly waters Sochi's lush vegetation and pebbly, sandy beaches. If it snows, it won't stick around long. There's basically no winter ice. And, oh, dear, this is the time of year when nature's band starts playing "Stormy Weather" along the coast there.

So: no snow, no ice, rain, and sometimes vicious storms. What were people thinking when they chose this for the 2014 Winter Olympics?

Well, they were thinking one of Russia's nicest resort towns would be fantastic to throw such a shindig in, is what. I mean, for the indoor winter sports stuff, all you need is to build really big buildings and keep 'em cold inside. Like Seattle, Sochi's winter climate isn't totally horrible - there's plenty of days where you can go happily wandering around enjoying some of the winter chill without freezing to death, which makes strolling around an Olympic Village a treat. And as for those alpine sports you can't stuff in a building,* I did mention Sochi's bang against the Caucasus mountains, right? Only 25 miles (40 km) from some of the greatest slopes ever, with the kind of lovely snow that makes skiers weep with joy. You can zip right over for the slalom, and nip back to the city for the figure skating, without losing a bunch of time in transit. Perfect! Makes me think Seattle isn't such a bad place for a Winter Olympics - we're practically twins.

But we're twins in more than just the gorgeous mild winter (with, granted lotsa rain) combined with the glorious ski possibilities less than an hour away. Both cities are low-elevation, on water-logged sediments and wetlands. Both cities are subject to flooding and landslides. Both cities are where and what they are because of the immense mountains rising behind them - mountains that are there due to the force of colliding plates, and subject to all of the seismic dangers that entails.

Building an Olympic Village from scratch in an area like this is a gargantuan task. And it starts with an assessment of the particular challenges and risks the site poses. I've read a paper that does just that: Engineering Geological Conditions and Protection of Olympic Park Territory in Sochi. And lemme tell ya: that paper doesn't make for particular happy reading. The authors were optimistic, but pulled no punches. This wasn't going to be easy.

The site chosen for the future Olympic Village was the middle bit of a place called Imerekinskaya Depression, a long, thin terrace right down by the water. This location, in the Adler District of Great Sochi, was "wild and boggy," the authors said. No kidding. These were wetlands, sparsely populated except by migratory birds and other denizens of wetland areas, with few humans and aging infrastructure. The land here was mostly deltaic, a hodgepodge of river sediments dumped when the Mzymta and Psou rivers on the west and east finished their journey from the mountains and discharged into the sea. As you head from coast toward the mountains, those river sands and pebbles, intermingled with marine deposits left by the Black Sea's occasional inundations, are overlain by landslide debris, glacial sediments, and more crumbly river deposits.

For ten million years, rivers, sea and ice have been leaving land here, but it's not the kind that will make a builder scream with joy. Especially not one who knows his seismic stuff: this is the kind of waterlogged, mostly unconsolidated sediment that loves to experience liquifaction in an earthquake. When these soils get a strong enough shake, they start behaving like liquid rather than solid stuff.

That's no bueno for buildings. Add that to the fact that Sochi is located in a prime location for really big earthquakes, and you've got a recipe for alluvial soup with structures stuck in.

As if that's not headache enough, planners and builders had to contend with the fact that the rivers like to flood in all seasons, but especially adore bursting their banks in winter. And with an average elevation of around 1-1.5 meters (3-4 feet) above sea level, those winter storms could drive waves right up the beaches and into the Village. Before humans started serious mucking about, the sea liked to go between 20-200 meters (66-656 feet) inland. Whee.

And it was in this wet, wild, dangerous area that the Russians were tasked to build 100 facilities for the Olympics. You had to put in housing for the athletes, their support staff, and other official folks who make the Olympics happen. You needed the arenas and stadiums where the events would be held - 8 facilities meant to accommodate between 3,000-40,000 people at a time. You needed hotels for the tens of thousands of Olympics-watchers, facilities for the media, shops, restaurants, and all of the incidental extra buildings required for putting on a major event. You had to factor in transportation, scenic viewpoints, seaport and shore protection structures, fire stations, pumping stations, sewage treatment plants... you're basically building an entire city. On ground that likes to flood, and basically turn to liquid when the earth shakes. Fantastic.

Existing drainage was a joke. So the catch-water drains had to be cleared out, leaving the Russians with at least 5000 cubic meters (176,573 cubic feet) of sludge that couldn't be used to infill the low areas - it had to be properly disposed of. (Unfortunately, construction hasn't proved as clean as the Russian government had planned.)

The plans called for turning the above-ground drainage to underground systems. Existing canals and ditches would be filled, and in their place, a network of pipes, connection pits, and pumping stations would be constructed. The current groundwater level would be held steady, excess water channeled to treatment facilities, and then fed to the sea through a deep sea outlet. Ponds on the surface would not only make the grounds lovely, but help control water levels. Artificial fill, carefully packed down, would take the surface up in elevation by an additional 2.5-3.5 meters (8-11 feet). That's 4.8 million cubic meters (over 6 million cubic yards) of material trucked in and packed down.

And all of this had to be done with earthquakes in mind. I hope the architects were genius, because while I hate to see wetlands go under and a lot of people crowded onto dangerous ground, I can't deny the results were lovely:

Next episode: we'll take that half-hour trip to the mountains and have a gander at the alpine village. From sea-shore to slope before you can ask, "Are we there yet?!"


*Well, not Olympic-caliber ski slopes, anyway - you can actually do a decent ski resort indoors, though!


Koff, Gregory and Chesnokova, Irina (2008): Geological hazards assessment Sochi territory in the context of preparation for the 2014 Winter Olympics. International Geological Congress, Oslo [abstract].

Osipov, V.I. et al (2011): Engineering Geological Conditions and Protection of Olympic Park Territory in Sochi. Water Resources Volume 38, Issue 7, pp 859-867.

"Sochi 2014: Why Summer Resort Makes Perfect Winter Olympics Venue." The Voice of Russia 16 Aug. 2013. Last accessed: 2/3/2014.