Concrete blocks

Walked Misty in Bitts Park, Carlisle this morning and  was very surprised to see these concrete blocks in the river.  Initially I thought they'd been washed up there but on closer inspection it looks as if they've been put there to protect the bridge.  Looks very odd and messy.  Further over there are huge rocks.  Hard to believe that in last December's flood the water was near the top of the arches!  Across the other side of the river is Rickerby Park where we often walk.  Had some drizzle today, first time for ages.