Groves and water

Hi!
I recently finished my Herobrine structures data package, but I always ran into problems that I couldn't resolve.
The main problem is that trees that are near water will spawn directly above the water, while the other half of the grove will simply spawn on the surface.
I need to do something to stop them from spawning underwater (I think there is a solution to make them stop spawning very close to water)
Hope you can help me with the code
Thank you :)