Hey guys, I've been having a problem defining and shaping a pond using Autodesk land Development Desktop/Civil Design, and I've been looking for some help. This forum seems to have some knowledgable people and I was hoping to get some advice. Let me describe my problem:

I have a wetpond on a sloping site, the wetpond is kidney shaped and will have a permanent water surface @ elev=92.5 The top berm of the pond is 98.0, and the bottom is 87.0

The pond is huge, mostly to provide fill for the sitework, but anyway, the side slopes are 5:1 with benches every 4' of depth. the benches are 6' wide and are sloped 0.01666667

The side slopes run from elev 98.0 to elev 94.1 @ 5:1 then a 6' bench to 94.0 then 5:1 to elev 90.1 then a 6' bench to 90.0 and then 5:1 to the bottom of the pond @ elev 87.0

I've used the Grading/Pond commands in Civil Design to define a pond perimeter, set the side slopes and benches, the top elev and bottom elev. When I run the pond design, all works out perfect until the bottom bench. After the bottom bench, for some unknown reason, it changes my side slope from a 5:1 to the bottom at 87.0 to a 2:1 to the bottom at 87.0 - SO: I am ending up with a pond that drops 4' in elevation after the bottom bench at too great of a slope. I've rerun the pond several times and each time I end up with the weirdness at the bottom. It's driving me crazy,and I'd really appreciate any help... I've been through the help files a dozen times and I can't find a solution. Thanks.