How can I make my entity ignore the slowing effect of water and move as fast in water as on land?

Hi! I'm creating a mod, and I'm going to create a rather interesting concept for an entity that, when you hit him, chases you very quickly. I've already done that. The problem is that this entity is very slow in water, and I wanted him to move just as fast on water as on land. What can I do to make this entity "ignore" the slowing effect of water? I haven't seen anyone yet who had a similar question to me, and I find this feature very useful for my mod.