Problem animation shallow lakeside

I’m trying to make a model of lake Ohrid (Macadonie).

The lake has a length of 30 km and a width of 12 km.
The scale I use is 1 unit in Blender is 100 m.

In de middle the depth is 280 m, at the shore the depth is between 1 and 5 m. The model is far from finished, but when I made a first animation something strange is happening I can’t solve.
See http://www.dailymotion.com/hzhenk/video/x6y2lt_00011600

The problem occurs at the border of the lake where the lake is shallow.

So does anybody has a solution

You need to describe to us what you are doing … broken English is okay … and what it is that you think is wrong.

It obviously looks to me like the problem has something to do with the surface that represents “the bottom of the lake,” which appears to be a fairly coarse polygon mesh that seems to be “showing through” when it is not supposed to.

For instance, what characteristic of the lake-surface are you animating, and with what? Is it a normal-map or a displacement-map? And so on.

I have added the blendfile.
First layer is the terrain mesh, second layer is the water surface (face mesh)
Even when zooming the overlap between water and terrain is changing.

The terrain mesh exits of the lake-ground and the mountains surrounding the lake.
At the border of the lake the level goes from z=-0.04 to z=+0.06, the mountains are all higher then 0.06.
The water surface is on a z level of 0.000
The water mesh is a rectangle and bigger than the actual lake.
The parts of the water mesh layer below/under the terrain mesh is not shown, this works properly.

When the z-distance between water surface and the ground of the lake is big enough there is no problem.

Problems occur when the distance between the lake surface and lake ground/bottom is small. In this area it looks like terrain and water surface are switching.

I also have problems with zooming in, at some point zooming in just stops, it is not possible to zoom in further.

I’m using blender 2.47

Attachments

ohrid3.blend (399 KB)