From the Wikipedia page [1] A tributary of the River Wandle, Norbury Brook rises near Lower Addiscombe Road and flows north-west through Selhurst, Thornton Heath and Norbury to join the Wandle at south Wimbledon. The brook continues west, to form the boundary between Norbury and Streatham on London Road at Hermitage Bridge, where it is one of the few rivers remaining overground in the area. West of the bridge the brook becomes the River Graveney, where it flows on to join the Wandle, and ultimately the River Thames.