After the 1.13 update, player can't use resource packs to change the water tint anymore, so it's impossible for them to pretty much modify the colors of the water textures!
I felt like this was a bug because it is possible to modify the foliage and the grass in the resource pack colormap folder, but it's not possible to modify the water tint!
A possible fix would be adding a new gradient in the colormap folder called water.png