How can I fix semi-broken textures in Trials Evolution?

I've been having this problem for a while and I've never thought to ask until now. Since I have bought and played Trials Evolution, I've had issues with water textures, large masses of dots appear on bodies of water, it looks something like this;

It's quite a bit more prominent than that, it isn't represented as well in picture. I was wondering if this is a client side issue or not, and how I can fix it.