rjzimmerman:

Excerpt:

Yet unbeknownst to many — presumably including a decent number of Britons — there are dozens of smaller rivers and canals flowing through the heart of the British capital city aside from the Thames: the Effra, the Tyburn, the Walbrook, the Westbourne and the once-mighty Fleet to name a few.

So why then do these waterways go largely unmentioned and unnoticed?

The answer is a straightforward one. It’s because you can’t actually see many of them as they were buried deep beneath the city streets eons ago.

Thanks to environmental nonprofit 10:10 Climate Action, the so-called “lost rivers” of London are back in the news. While it might come as a surprise that these mysterious sunken waterways are being touted by the group as a promising green heat source, it’s likely an even bigger surprise — or at least to those who aren’t familiar with London’s vast, complicated and filth-riddled history — that they even exist at all.

London isn’t the only city to be built atop subterranean watercourses that have gradually been paved over and buried, some in their entirety, to make way for new development. Toronto, Brussels, Vienna, Moscow, Sydney, New York City and Philadelphia all are home to rivers, creeks, brooks and streams that have been forced underground. It is however, the first major city where there’s a movement underway to tap into its lost waterways on a city-wide basis as a means of curbing greenhouse gas emissions.

Steamy underground sewer systems, whether they were once natural watercourses or not, are primo places to extract natural heat using water-source heat pumps, which the Guardian describes as working like “reverse refrigerators.” Once extracted, this captured heat can be transported to neighboring office buildings and residential complexes, negating the need for burning fossil fuels for heat, which is the norm in London. In turn, a significant amount of air-polluting carbon emissions are avoided.

How London’s ‘lost’ underground rivers could help curb carbon emissions