I created a water particles but they seems to hang over the surface, why is this happening?
Still the water hangs over the ground even with Collision Surface Thickness zero:
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In other words, try dropping your collision thickness to '0' and particle radius to < 1.0.
Your domain is too big, scale it down as much as possible to just cover expected simulation range in a scene. Something like this ...
You use a lot of colliders with very chaotic topology. I would suggest to use one simple that would be faster in simulation and it prevent from leaking water. Bake simulation and for rendering disable this simple collider in Outliner.
In this example I used a subdivided Plane with Shrink Wrap modifier > Projection > Z to quickly recreate your colliders.
Increase value for "Resolution Divisions" that is too low. 64 is not enough to generate a grid dense enough to bring water closer to collision objects. One division is represented as a cube in domain corner. Amount of divisions is always a longest side of domain divided by this number.
So as you can see each time the Resolution Division is increased, simulation is closer to collider thanks to detailed grid (division) of domain.