Ground investigations have begun to find an underground river running beneath Greendale Fields, behind Dulwich Hamlet FC’s Champion Hill ground.
Southwark Council discovered the subterranean watercourse as part of a public consultation it carried out last year on plans to transform the area of metropolitan open land into a new public park.
Officers are currently trying to pinpoint the exact location of the stream so that it could be exposed and incorporated into the plans for the site.
The investigations involve the use of a radar and digging trial holes in various locations on the site.