Residents have been invited to comment on a range of ideas to strengthen sea defences along the Severn Estuary.
Environment Agency Wales warned unless steps were taken, flooding could put several areas along the south-east Wales coast at risk of flooding.
Plans include raising the sea wall at Penarth, Vale of Glamorgan, and improving embankments in areas around Cardiff, Newport and Chepstow.
The plans can be seen at Marshfield, near Newport, and Magor, Monmouthshire.
The public can also comment on the agency's website.
It has drawn up a series of short and long-term proposals and warned that with sea levels expected to rise and storms to become worse, just maintaining defences at their current levels would see flood risks rise.
In Cardiff, "phased improvements" between 2060 and 2110 to "keep pace with climate change" are planned, including increasing the height of embankments.
Work is also planned around Newport's Transporter Bridge and to safeguard the sea wall at Penarth.
Elsewhere, other improvements are proposed around Wentlooge between Cardiff and Newport; between Uskmouth and Redwick near Newport; between Redwick and Portskewett; and around Mathern near Chepstow.
The Severn has the second highest tidal range in the world.