The aim of this research is the study of the shock wave interaction with a relatively small quantity of water in a semi-confined environment. The semi-confined environment was almost a cube whose side faces are open and having a volume of about 7 m3. The deformation of target plates bolted onto the enclosed face was assessed. These were either unprotected or protected by plastic bags filled with water. Three quantities of water were tested: 4, 10 and 15 kg. The residual deformation of the test plate was assessed and also the maximum dynamic deformation. This latter was obtained by the squeezing of a hexagonal aluminum tube and by digital image correlation. The results have shown that both deformations, residual and dynamic, of a 5 mm thick steel plate were decreased when it was protected by water. All things considered, this method seems to be of interest for blast protection purposes in semi-confined volume but some further works are still required.