Opel

Not sure on this, but it sounds to me like

warm shallow waters sweeps shelves so the cockle's shy

shelves being ridges or levels of sand (?) where cockles live, the cockle being shy because it peaks as the edge of the sea try's to tempt it but refusing to come out for anything but the deep. A world of permanent retreat and meaningless but well meaning people.

And I'm sure it's crisp flax squeaks tall reeds

and definitely stood on ground

All about being beached, obviously