Hi Nige
I'd play it safe and take up bird watching.....
Seriously though,river side land land is getting thin on the ground and as such attracts a premium but the system of dams and irrigaton channels in place along the Ebro should prevent serious flooding.The river levels do rise and fall slightly,more noticably up river but this is controlled.
Just to throw a dampener on things,have you thought about the mozzies,flies and all the other winged devils that frequent the river bank.......we've timed it and we get about 15 seconds of G & T time before the white flags go up and we bid a hasty retreat............