The Tideway Tunnel is a major sewer built under the River Thames in London over the past decade. It was constructed because the sewers built by Joseph Bazalgette, a Victorian engineer, for a city of 4m people could no longer cope with the waste generated by 9m people combined with storm-water runoff. For years, the solution was to discharge untreated sewage directly into the Thames, where it washed up and down with the tides.
When the Victorian sewers on the river banks are overwhelmed, foul water flows down colossal vertical shafts—up to 20 metres wide and 64 metres deep—to reach the tunnel. The liquid spins down in a vortex rather than pouring. At Blackfriars and six other places along the river, from Wapping in the east to Putney in the west, the city has bulged into the water to accommodate the tops of these shafts, creating new public spaces for people to wander and sit.
The new parks sit on top of the drop shafts. All have tall twisted vents to carry sewer gases away from people at ground level. The largest intrusion, at Blackfriars, is a rounded triangle containing a cluster of monoliths by the artist Nathan Coley. Tyburn Quay, opposite the London Eye, has bronze sandbags; Effra Quay, near the headquarters of the Secret Intelligence Service, has seats in the shape of toilets. Two of the new spaces, in Westminster and Chelsea, are washed by the river at high tide. Many are faced with granite to help them blend in with Bazalgette's Victorian river bank.
Better to be nouveau than never to have been riche at all.