Pond Boss Forums POND CONSTRUCTION Selecting a site Pilings

I had a 3/4 acre oval pond installed two years ago that is now full. During construction they hit sand at 19ft center and stopped there and lined the bottom and sides with clay. The pond is located downhill with rather steep sloping sides. I have ordered a floating dock that I will install this spring, 24' long in a "L" shape with steps down to a ramp. My question is how to properly anchor it.

The leading edge of the "L" is over about 8' of water in an area of the clay lining, but not near the depth or area where sand was hit. My preference would be to install sleeves and 1-7/8" pilings for stability, but I am concerned about any chance of causing a leak. Is this something I should be concerned about? Obviously if this method is not recommended then I will have to look at submerged concrete anchors or shore based tethering.

The dock location photo shows the pond as it was filling, the yellow pipe is the overflow. The dock will be located straight out from the old deck platform I placed on the bank. If the photos cannot be viewed for some reason you should be able to cut and paste the http link to pull up. Thanks.

https://www.dropbox.com/s/qd4hpd66ktxqorb/DockLayout2.jpg?dl=0
https://www.dropbox.com/s/qjsdkm8q955suu6/DockLocation1%282%29.JPG?dl=0
https://www.dropbox.com/s/b0qfzqqb2o6mz4q/DockLocation.jpg?dl=0