Tell us about yourself!
I built a rink following this insructable and found my yard was more uneven than I thought (one corner was low that I didn't measure). I added some water, let it freeze and then lifted the pipes in that corner and put bricks under the pipes. That's the best I could think of in a pinch. Better would be to somehow level out the low spots along the perimeter ahead of time. Another thing to note is that thin wall pipe needs to be used for the clips that go over the frame (frame can be thicker pipe) so that it can flex enough to go over the pipes and hold the liner. Also, it is very easy to tear the liner when putting the top pipe clips in place. E6000 w/ Tyvek tape works pretty well to seal tears. Next time will sand the top pipe edges more.