Stage 11: Eymet to Pau

The eleventh stage takes us from Eymet in Dordogne to Pau in the Pyrenees. Pau is a classic city for the Tour — it was the start of the stage that Chris Froome won last year into Bagnères-de-Luchon — but it is also home to the Stade d’eaux-vives Pau-Pyrénées, the Pau-Pyrénées Whitewater Stadium.


The city of Pau is sited on a ford across the Gave de Pau, and there are many rapids within the city. These natural rapids are used enough by whitewater enthusiasts to have its own slalom gates installed.

The whitewater arena is the brainchild of the Estanguet brothers Patrice, bronze medalist at the Atlanta Olympics, and Tony, gold medalist at the Sydney, Athens and London Olympics. The facility hosted Canoe Slalom World Cup races in 2009, 2012, 2015 and 2016, and the Canoe Slalom World Championships will be held in Pau this September.


Stage 10: Périgueux to Bergerac

The first stage after the rest day took us to the banks of the Dordogne in Bergerac. We nipped into the watershed of the Dordogne last year, but then we were more interested in the navigation on the upper reaches of the river. Today, we passed through the Vallées des Beunes which is a Natura 2000 site on the Beune, a system of rivers which is a tributary of the Vézère, itself a tributary of the Dordogne. We are once again on limestone bedrock. The resulting karst landscape around Les Eyzies includes many caves, including the caves of Lascaux home to the famous cave paintings.


The limestone also produces a set of alkaline environments in the Vallées des Beunes, including unique alkaline wet meadows that are called fenasses. The fenasses seem to be incredibly sensitive to water levels, so that conservation of these wetlands (the responsibility of the Syndicat Mixte du Bassin Versant de la Vézère en Dordogne) consists largely of making sure that the water level is not too high, in which case the fenasses turn into marshes, or too low, in which case they dry out and become grasslands or forests. They also, like many wetlands here in North America, have a problem with the invasion of Phragmites reeds.

Marcel Kittel easily pulls in front of the others to win his fourth stage out of ten this year. They get one more chance to take him on tomorrow before heading to the Pyrenees.

Stage 9: Nantua to Chambéry

We rode over the Grand Colombier last year on the way to Culoz where Jarlinson Pantano outsprinted Rafał Majka. Today, though, we end on the south end of the Lac du Bourget in Chambéry, so it’s a good a time as any to revisit one of the largest lakes entirely on French soil.


Bourget is a fairly deep lake, around 80 m on average, and as a result, it is meromictic, meaning that it doesn’t always mix vertically. Lakes develop thermal stratification as the summer sun warms the surface water, which, because it is less dense than cold water, sits on top of cooler water at the bottom of the lake. As the surface cools off during the fall, the water at the surface becomes more dense and falls to the bottom of the lake, overturning the water. This overturning is critical for biological productivity in lakes as it mixes the oxygen-rich surface waters with the nutrient-rich bottom water.


This is how stratification develops in a dimictic lake. In contrast, the Lac du Bourget doesn’t fully mix over the course of the fall and winter.

Vinçon-Leite et al. (1995) discovered that Lake Bourget doesn’t mix all the way from top to bottom in a normal winter because the lake is so deep. Only in very severe winters does it get cold enough to overturn the entire water body. This lack of mixing creates a semi-permanent hypolimnion, a region at the bottom of the lake with very low oxygen levels.

After a long breakaway yesterday and today, Warren Barguil very nearly pulled off a win with a sprint to the line in Chambéry, but Rigoberto Uran beat him out by a hair. A sad day for Richie Porte, though, and we hope that he recovers from that absolutely horrific crash down the Mont du Chat.

A rest day for the peloton and for Les Eaux tomorrow, but we’ll be back on Tuesday to see how well the sprinters can recover from these grueling mountains.

  • Vinçon-Leite et al. (1995). Contribution of mathematical modeling to lake ecosystem understanding: Lake Bourget (Savoy, France), Hydrobiologia

Stage 8: Dole to Station des Rousses

We enter the Jura for an exhilarating day of mountain climbing. Along the way, we rode through the Région des Lacs du Jura français.


The three lakes that we came closest to this afternoon are the Lac de Chalain, largest of the Jura lakes, and the Lacs de Chambly and du Val. All three of these lakes sit in glacial valleys carved out of the limestone bedrock. They are all surrounded by fairly sharp walls leading up to the plateau on which the other lakes sit. The peloton rode along this plateaus as they passed Chambly and Val.


Lac du Val is the first lake in the picture, Lac de Chambly is further behind. We’re looking northwest.

The shores of the Lac de Chalain have been inhabited for thousands of years, and the remains of a Bronze Age settlement can be found preserved in the muddy bottom of the lake. This village, built on stilts over the lake, is one of 111 pile dwellings around the Alps which form a UNESCO World Heritage Site.

We barely had time to admire the landscape as the gigantic breakaway drove towards Station des Rousses. A very solid performance from Serge Pauwels today (as I predicted!), but the young Albigensian Lilian Calmejane pulled off an impressive win.

Stage 7: Troyes to Nuits-Saint-Georges

As promised we went up the course of the Seine, passing close by its source in the appropriately named village of Source-Seine. We finished in Nuits-Saint-Georges on the banks of the Meuzin, itself a tributary of the Dheune, which flows into the Saône, which flows into the Rhône.


The 18th century historian Claude Courtépée wrote about the Meuzin in his Description générale et particulière du duché de Bourgogne. He says it better than I could (forgive my very rough translation).

This town is on the Meuzin, which takes its source at the bottom of Vergy in the village of Etang; It has on its course from west to east, to the city, a forge, three good paper mills, two fullers, a bark beater, and ten flour mills; It goes to Quincey, Antilly, Argilli, where it receives the fountain of Premeaux, Villy, Corberon, Corgengoux, joins the Bourgeoise and falls into the Dheune at the port of Paleau. The city and the suburbs were flooded by the torrent and exposed to an obvious peril in 1712, 1713, 1747, 1757. It is in this last misfortune that the late Claude Marey, former Mayor and secretary of the King, exercised he generosity by saving from famine half of the inhabitants who had retired to the top of their flooded houses by carrying on a boat the bread which he cooked each day. He had deserved the surname of Boulanger, as was given to an illustrious bourgeois of Paris on such occasions in the 15th century. Mr. Soucelier and other citizens also distinguished themselves by an active zeal in relieving their compatriots. The bed of the Meuzin, which is 32 feet wide, has been widened and deepened and is covered with good walls 12 feet high


This sculpture in Nuits-Saint-Georges records the height of the floods that it has experienced.

A quick ride into Nuits this afternoon. We fans of Dimension Data were robbed of a Boasson Hagen victory, but Marcel Kittel got there first by the width of a hair. We’ll get our wins from Cummings and Pauwels as we move into the real mountains tomorrow.

Stage 6: Vesoul to Troyes

When we started today’s very hot stage, any water the riders spilled that didn’t immediately evaporate would have eventually flowed into the Mediterranean. Vesoul lies on the Durgeon, a tributary of the Saône, itself a tributary of the Rhône. When we ended the stage at Troyes, water flows via the Seine past Paris and into the English Channel. When we leave Troyes tomorrow en route to Nuits-Saint-Georges, we’ll cross back into the Rhône basin and won’t be back in the Seine watershed until the final day as we head towards Paris. So I’ll take this opportunity to revisit the Seine, the disastrous floods which afflicted it in the early 20th century and some flood control measures that the peloton rode by this afternoon.


The Seine flooded Paris for some 45 days in 1910. This catastrophe caused some 400 million francs worth of damage (about $1.5 billion in 2017). To the Parisians of the early 20th century, something had to be done to prevent such floods from recurring, and that something was clearly a dam. The first dam was put on the Yonne River, forming the lac de Pannecière in 1949, followed by the lac d’Orient in the department of Aube 1966.


Le lac de Pannecière

To these two lakes were later added the lac du Der-Chantecoq on the Marne and the lacs du Temple et Amance which we passed by in the regional natural park of the Orient Forest. The lac du Temple is named after the Knights Templar who apparently owned land in the area.

These four (because the lacs du Temple et Amance are considered one lake) form “les grands lacs de Seine” and are managed by a regional watershed management body called EPTB Seine (EPTB stands for établissement public territorial de bassin).

A jump into the lakes looked nice on this hot day for the sprinters in Troyes. A solid win by Marcel Kittel, but he’s still got a big deficit on Demare to get into green.

Stage 5: Vittel to La Planche des Belles Filles

The fifth stage of the Tour takes us up into the Vosges Mountains passing on the way Le Plateau des Mille Étangs — the Plateau of a Thousand Ponds.


A pond near Ecromagny

We saw another land of many lakes last year when the sprinters raced into the Parc des Oiseaux in Villars-les-Dombes, but while those ponds were man-made fish ponds, the ponds of the Plateau were carved by glaciers as they retreated. I’ve seen this landscape referred to as a fjeld, a Scandinavian word for a high glacial plateau, and Matthew Keenan called it the Finland of France during the broadcast today.

Many of the small ponds are surrounded by wetlands, and it’s possible to find ponds in various stages of the hydrosere succession. The edges of the ponds are colonized by emergent marsh plants. As the marsh plants die, the dead plant matter is incorporated into the soil and forms peat. As the peat builds up, sedges move in. Eventually the pond fills up with peat, and forests can establish on top of the peat.


Now the existence of true hydroseres has been questioned in the ecological literature. Lee Klinger makes the argument that very rarely do we actually see a pond turn into a forest over time. More often, we make inferences from the spatial patterns of vegetation that we see on the ground now. Instead, you might have many different possible progressions of vegetation. You might end up with a bog that stays a bog and never turns into a forest.

My impression is that the consensus among ecologists is that succession is a lot more complicated than a linear progression from one state to another. So the hydrosere model may not be the most scientifically sound one to explain the diversity of landscapes we find on the Plateau. I think it is helpful to remember though, that when you see a bog on the Plateau, that could very well have been a pond in the past. And when you see a pond, it probably won’t stay a pond forever.

Up the mountain it was Fabio Aru leading the big names of the Tour. Starting to see the GC shake out, but we have a few more days of sprint finishes before we can see how much damage the Vosges did.

Stage 4: Mondorf-les-Bains to Vittel

Stage 4 takes us from Luxembourg into Vittel in the Vosges, home to some very good mineral water:



Vittel is another spa town like Chaudfontaine and Aachen and like Mondorf-les-Bains, the Luxembourgish starting location of this stage. Vittel, as most of these spa towns, was used by the Romans, but the modern baths were established in 1854 by lawyer and sometime political exile Louis Boulomie around what’s now called La Grande Source.


Of course, Vittel probably gets the award for the most often seen water in the Tour de France. It lends its name to the bottled water brand that sponsors, among other things, the giant spider that holds the flamme rouge at one kilometer before the finish. Vittel the brand appears to have worked out a cool payments for ecosystem services plan with the farmers in the region to help prevent nitrates from leaching into the groundwater that is later bottled.


Quite a bit of carnage inside la flamme rouge this afternoon. Let’s hope the race settles down after this drama.

Stage 3: Verviers to Longwy

The third stage of the race takes us from the Belgian town of Verviers through Luxembourg from north to south into Longwy in France. Verviers sits on the Vesdre river, one of the streams which drains the High Fens (French: Hautes Fagnes; German: Hohes Venn), a Ramsar wetland of international importance.

By L.1951a - Own work, CC BY-SA 3.0,

The High Fens occupy a plateau in southeastern Belgium — the highest point in Belgium is a signal tower in the High Fens. The Fens themselves are actually raised bogs which receive their water from the high rainfall on the plateau.

From the High Fens flow several streams, including the Rur, which we crossed yesterday at Jülich, and the Vesdre, which flows through Eupen, Verviers and Chaudfontaine (which we also passed through yesterday on the way into Liège) before flowing into the Ourthe and then into the Meuse, which later joins the Rhine to form the Rhine-Meuse-Scheldt delta.

Verviers was once a center of the Belgian wool industry, which grew because of the ability to wash wool in the water of the Vesdre. Wikipedia says that the Vesdre water has high acidity as it flows out of the acidic bogs of the High Fens. However, George Tanner, American consul at Verviers, seems to suggest that the waters of the Vesdre are naturally rather alkaline, which is not good for wool washing. Tanner claims that it was only after the construction of the dam on the Gileppe that Verviers could obtain appropriately acidic water for its wool.

By Paul Hermans - Own work, CC BY-SA 3.0,

Stage 2: Düsseldorf to Liège

The first road stage of the Tour takes us from Düsseldorf, up the valley of the Düssel before turning around and heading west into Belgium for a sprint finish at Liège on the Meuse river. Along the way, we passed through Aachen, home of Charlemagne’s thermal baths.

The name Aachen comes from the Latin Aquae Granni, the “waters of Grannus,” a Celtic god of healing, which indicates that the hot springs were used by the native Celtic people before the arrival of the Romans. The facilities at Aquae Granni were expanded by the Romans.


A sketch of the Roman baths at Bücheltherme

According to his biographer Einhard, Charlemagne loved the hot springs at Aachen so much he built his palace there:

He enjoyed the exhalations from natural warm springs, and often practised swimming, in which he was such an adept that none could surpass him; and hence it was that he built his palace at Aix-la-Chapelle, and lived there constantly during his latter years until his death. He used not only to invite his sons to his bath, but his nobles and friends, and now and then a troop of his retinue or body guard, so that a hundred or more persons sometimes bathed with him.


Charlemagne oversees the construction of Aachen

The hot springs of Aachen are found in two very straight lines running southwest to northeast through the center of the city and through the suburb of Burtscheid. These lines of springs fall along outcrops of Upper Devonian Limestone that are pushed up to the surface by a pair of thrust faults (the Aachen and Burtscheid thrusts). Hot groundwater rises through these limestone layers to spill out in the springs.

Screen Shot 2017-07-02 at 5.19.57 PM

A cross section of the rocks beneath Aachen. The blocky and spotted white layers are Upper Devonian limestone. From Herch 2000, Environmental Geology

A hot bath is probably just the ticket for Marcel Kittel and the other sprinters, not to mention the breakaway duo of Taylor Phinney and Yoann Offredo. Aachen is probably a bit too far away from Liège at this point, but nearby Chaudfontaine was called by Victor Hugo “la violette des stations thermales.”