Water render glitch?

Hello everyone! just a small question:
when i add water for my terrain, the texture spazzes out like this:
17714-waterglitch.png

It looks like it’s trying to display both textures at the same time, even though the water has no alpha value, and is a few metres above the terrain. the terrain under the water is flat, except for the landmass on the bottom left.
how can i fix this render glitch?
P.S. It happens with a normal stretched out cube too, as well as a small piece of water.
Rsising the water doesn’t help, aside from the fact that that it will flood the terrain on places it shouldn’t this glitch happens pretty low too, and changing the near clipping plane makes it look like i can see trough things when i walk into them…
Thanks in advance
-bolibob2

Sometimes you either just need to change the Y position, or just zoom closer.

Move the water just a bit lower than the terrain.