I think in order to drain surface water around a level area, a contour of a lower elevation must essentially surround the entire area (contour 110). Not sure if you found these on the are forum site...some helpful hints:
Also be careful when modifying contours near trees, consider their drip line.
In case you haven't found them, here are some alternate vignettes:
http://www.areforum.org/forums/showthre ... Alternateshope this is helpful.
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