How about starting again, perhaps a raised fountain so it's well off the grownd and
getting the cable buried deeper and in conduit will make things a lot safer.
Love the sound of water in the garden, would be a shame not find the right place for
it, you have all the eguipment and pumps etc are not cheap.
As tonybloke suggested, porous membrane under pavers or stones will keep grass away.
Have fun and enjoy,
floss xxx