One of the experts will likely jump in soon. I'm guessing the dirt wasn't the right type (clay / other soil mix), or it wasn't properly compacted (moisture / weight / etc.), it was too great a slope, or something. All I can say is that I feel for you. My main pond dam done by professionals is also about six months old and nearly full. So far, so good.

The one mini-dam (sediment basin) that I personally completed before weather prevented more has also slipped a bit. It isn't big and the drawbar on the 4-wheel drive tractor pulling the scraper broke at start of weekend so we did it with dump truck and trackhoe. I'm sure my mini-dam wasn't packed as well as it should have been. It also had a pretty steep slope. Was going to improve it some, but rains and work... I still will improve it this summer...

Good luck with your pond and let us know how it goes.

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