Walking is permitted on the water authority property, but no swimming or messing with the water. Park outside the gate even if the gate is open.
This should be a short walk with some slight bushwacking. It is a field puzzle, so it could take a short or long time, depending on how unwrapped the mummy has become. There are two ways to solve it, one might be easier than the other.
Congratulations to carels for being the first to wrap up the mystery of the mummy!