Over five years ago, the artist Chloe Dewe Mathews traveled to rural Gloucestershire, to the source of the River Thames. It was the beginning of a project that saw her slowly moving east with the water, taking photographs of the people she encountered along the way. Dewe Mathews came upon traditional, modern, and makeshift ceremonies, boat burnings, baptisms, and teenage rites of passage. She observed ship-spotters and mudlarkers (people searching the sludge for Roman and Saxon antiquities). Her 229-mile journey ended at the river’s mouth in Southend-on-Sea, where the Thames meets the North Sea. In this exhibition, snapshots from the project are on display, logging the flow of life. —E.C.