Pond Boss Forums POND CONSTRUCTION Soil questions Pond Leak - any thoughts appreciated...

The plastic liner is useless and should be removed some ponds in NY take 4to5 fillings before they bind the blue clay is bluestone that has broken down . If you are going to use this clay in existing soil it has to be knitted into the existing soil a min. of 10" it is hard to work with and should have little moisture.Follow Ottos advice and see if the water penetrates the sphere and falls apart and the perk.
If there is a lateral cracking in the shale against the layers then you will have drainage problems if not and he covered the shale it could take up to two years to form a seal. If you want to know if it is leaking out the bottom I would drain it and you will be able to identify the area. If it appears to be fully sealed with clay that has drained from the sides then look upwards.

good luck