The pool, on farmland close to the Harrowgate Village district of Darlington, may well be ephemeral - it was photographed following a spell of a number of days of heavy rain - it's not shown on OS maps at any scale. The gulls are probably black-headed.
Uploaded to Geograph by Trevor Littlewood on 19 November 2015
Photo © Trevor Littlewood, 19 November 2015. Licensed for reuse under this Creative Commons licence