I don't get why you named it after the first 3 digits of pie... *confused*
The wording is a little awkward, and might need some work.
Elaborate on "upkeep" a little. How does it differ from the "absorb X per turn" as is found on flooding?
Lastly, I notice you drop both the cost and the upkeep for the upgraded version. This seems like a little too strong of an upgrade benefit.
Typically, upgrading can be weighted at roughly 2
worth of effective cost.
Absorbing 1
per turn is typically weighted at roughly that amount already, so the effective bonus of the upgrade seems roughly twice as powerful as it should be.