I have already written about the river Po and the natural trails that you can enjoy near Vercelli. You can also enjoy the river if you go towards Valenza from Casale Monferrato. We discovered this area because we were particularly interested to find a place where the children could dip their toes in the water without too many dangers.
We stopped at at the bridge over the Po, parking on the Valenza saide of it (be careful to park before the Natural Park sign because you may get a ticket - we did!, although it was only a warning). Here not only you can enjoy strolls along the banks, but you can reach the shore and enjoy the wide pebbly beaches and low water level.
This is a photo taken near the spot that we chose. We were there during a Spring weekly day, when Italian schools were still open so there was only another family on the other side of the river.
The weather was hot and the children enjoyed bouncing flat pebbles in the water. We dipped our toes in the chilly water, but I cannot say if it is safe to swim there as the currents can be quite strong. It was a lovely spot and very easy to find so we are planning anotehr visit at the first occasion.