Any wave of any kind will change direction when it encounters an obstacle. This bending is called

Diffraction

Explanation:

When any wave change its direction after encountering with any obstacle the bending is called diffraction. And it is mainly observed in the case of longer wavelengths. When wavelength of wave is smaller or comparable than the aperture of the obstacle the diffraction is non noticeable but if wavelength is larger than aperture, diffraction is extreme.

It sounds like you are describing refraction. Water is not exactly an obstacle, but when light encounters it, it does bend going through it.