He warned people diving or swimming around Wanganui to always check the water they were heading into.
"While jumping off the bridges isn't illegal in Wanganui, we do discourage it for that very reason, because logs and all kinds of things could be present just under the water.
"The floods have obviously changed the riverbed, but also with the floods has come a heck of a lot of driftwood and wood down on the bridges. You just don't know what you could be jumping on.
"You just have to look on YouTube for hundreds of examples of incidents where people have jumped off bridges into murky water, only for it to end with some serious injuries."
He warned the beaches would also be changed, and said to "listen to the lifeguards" as summer approaches.