keeping your staked lot staked

[Fishboy]

So, John, when a lot is staked by a surveyor the stakes are placed in concrete? The corners of my lot in Discovery Harbour were staked with white PVC pushed over rebar when we bought it. In the six years we've owned the lot, three of the stakes have been removed and the exact location has become indistinct. I know the location of each stake to within a few feet, so is it 1) important that I locate them exactly or 2) likely I'd find something solid if I dug around? Keep in mind the ground in my lot is leveled, but pretty solid, lava.

Aloha pumehana,
Brian and Mary
Lynnwood, WA\Discovery Harbour