How can I find depression contour lines? I already have find depressions via Fill-method, but now I try to detect them by using the contour lines, anyone have an idea ?
This ESRI blog post describes a method for finding depressions using contours. On a topo map depressions look like this:
Note that the above approach is not desgined to be programmatic, but simply relies on symbolizing the contour lines using different colors so that you can visually find lines which do not fit the pattern of stepwise increases.
My opinion is the vector/contour lines are more appropriate for a visual inspection, whereas your original raster is more appropriate for programmatic inspection. Having said that, however...
You might try doing a definition query for the shortest contour lines. As this would designate smaller perimeter measurements, which should be a trait shared by depressions. Of course this will require a heuristic to establish the maximum acceptable length for contours that signal depressions.
If you have a few known depressions---on the ground---that you can measure corresponding contour lengths for in your GUI, you could establish a quick and dirty rule just for the sake of testing the concept.