If WSDOT bought the land from you on which the wells were previously drilled, normally WSDOT would be purchasing not just the land, but all claims of inverse condemnation and trespass. If those claims were not included in the purchase transaction with WSDOT, you would still technically own those claims under Hoover v. Pierce County.
Every lawsuit involves at least three elements - liability, damage and the ability to pay.
The question I would have is: what are your damages?
What are your out of pocket expenses related to the drilling of monitoring wells on your property?
Absent any serious out of pocket expenses, you would be entitled to "nominal damages" for the trespass - but that might not be worth the money expended trying to fight the state.
I am not a WA attorney, laws vary from state to state, therefore you should always consult a local attorney.
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