The Talking Heads’ David Byrne sings: “under the rocks and stones, there is water underground...water flowing underground”, and at the start of director Caroline Bacle’s Lost Rivers, that’s just what we see.

Andrew and Danielle, a couple of outlaw “drainers” in Montreal, are sneaking into that city’s sewer/buried-river system by way of a golf course’s daylighted stream.

Like people who share a similar passion for belowground waterways in cities worldwide (for this film’s purposes, London, Toronto, Yonkers [New York], Seoul, and Brescia in Italy), this pair is exploring, mapping, and experiencing the routes of tributaries that used to flow into the St. Lawrence before Montreal’s urban enormity pushed its rivers away and out of sight.

Canadian Bacle documents efforts in other cities to bring old rivers—culverted and roofed over but still in their original courses, more or less—aboveground once again. A pair of Toronto architects’ ingenious, and natural, solution to rainfall-triggered overflowing sewage pipes got defeated years ago by a shortsighted city council, but activists persist. Seoul, South Korea, and Yonkers daylighted kilometres’ worth of old streams and revitalized paved-over inner-city wasteland.

And a group of erstwhile outlaw Brescia drainers got civic approval to form an association and today they take thousands of tourists underground to marvel at the ancient Roman bridges and medieval structures previously hidden from view.

Impressive--at times almost poetic--photography and interviews with some dedicated drainers, visionary urban planners, and long-time activists and volunteers give viewers a sense of why some of these sewer enthusiasts got started with their cause in the first place.

And the results with some of the reclaimed watercourses are remarkable, to say the least.

The key in most of the projects shown here is to get citizens involved in most areas of the work outside of heavy construction. As one New York planner puts it about Yonkers’ Sawmill Creek daylighting proposal: “When people own things, they take care of them. We want people to own this river.”

A Korean environmentalist mentions at the end of the film how people need to be reminded that in burying rivers, humans screwed up, but given a final chance to address that wrong, they can see the result and never make that mistake again.

“Once in a lifetime…”