The chain of lakes and ponds running through the Bois de Boulogne leads to a grand finale at the picturesque Grande Cascade. Cedar, pine and birch trees crown the small rocky hillside above the cascade. A pathway cut into the hillside allows visitors to walk through a grotto of fantastic rock forms, behind the curtain of the waterfall. Lakes, ponds, waterfall and the streams that connect them are all completely artificial.
Water was key to the Second Empire development of the Bois de Boulogne, from an ancient royal hunting ground to a landscape for leisure and recreation in the style Anglais. Lakes and pools, decorated with islands, bridges and pavilions, offered focal points, reflections and picturesque views. Streams and canals alongside promenades led the visitor through the woods. Dams, rills and cascades emphasised changes of level to animate a predominantly flat landscape. In an age of imperial ambitions and cheap labour, the enormous undertaking of digging the lakes and engineering the water supply didn’t limit the vision of the designers.
Work began in 1853 with the excavation of the main lakes. Initially these were supplied with water raised by steam pump from the river Seine, but this proved exorbitantly expensive to maintain. A piped supply was laid on from the Canal de l’Ourc, capable of supplying 18,000 m3 per day and then an artesian well was sunk, offering a supply of around 10,000 m3 per day. Water was delivered to the upper lake, Lac Supérieur, from where it was fed by gravity through the rest of the network. A reservoir upstream of the final cascade accumulated water through the night, to give a more spectacular flow of water at lunchtime, when spectators would be seated on the terrace outside La Grande Cascade hotel.
This archive photo (above) shows the cascade in 1858, less than five years after its construction. Today some of the ‘rocks’ are looking the worse for wear and the view across the cascade pool is marred by lines of parked cars, but by and large this fanciful landscape has matured well. At a time when few people had the opportunity to travel, the Bois de Boulogne offered ordinary Parisians a glimpse of far away places. Todays well-travelled visitors may be less easily impressed by a ‘genuine’ Swiss chalet or a dripping grotto but the Bois still attracts thousands of visitors to row on the lake, to sunbathe on the island lawns and to stroll, run, skate or scoot through the woods.
Today the water supply for the lakes and streams of the Bois de Boulogne is managed as part of the city’s network of water not for drinking – Eau Non Potable or ENP. It’s an extraordinary system, inherited from the nineteenth century city planners, that delivers river water by surface canal and underground pipes to streets, parks and gardens across Paris, for irrigation and cleaning. As part of a 2013 review of the ENP systems, the city council commissioned a report on water in the Bois de Boulogne and the Bois de Vincennes; water in landscape, leisure and biodiversity. A glance at the maps and plans that illustrate the report gives a sense of the imagination and vision of the planners and engineers who established the nineteenth century infrastructure of the city, and the scale of the challenges facing their present day successors. ……..