just drained my leaky pond & ordered an epdm liner & some underlayment. i've searched the liner sales sites for installation info, but haven't found much. somewhere i once read i should bury the edges. if that's the case, how deep should i bury them? are there any other important points i should know about installing the liner? pond is about 150'x75' & i bought enough liner to cover up to about 4' from the top of the pond.