Policy WSM12-Birnbeck Pier and environs Birnbeck island/pier is located some distance away from the mainland and is not located within Weston Bay so it is more vulnerable from a combined risk of high tides/surges and large waves being sourced within the Severn Estuary. WSM has experienced extensive tidal flooding in the past, most notably in1981 when a significant tidal storm overtopped and damaged large sections of the tidal defences. Joint tide and wave flood risk is a significant constraint