A port district may acquire by purchase, for cash or on deferred payments for a period not exceeding twenty years, or by condemnation, or both, all lands, property, property rights, leases, or easements necessary for its purposes and may exercise the right of eminent domain in the acquirement or damaging of all such lands, property, and property rights, and may levy and collect assessments upon property for the payment of all damages and compensation in carrying out its purposes, and such right shall be exercised in the same manner and by the same procedure as provided for cities of the first class insofar as consistent with this title, and in connection therewith the county treasurer shall perform the duties of the treasurers of such cities.
RCW 53.08.010
Eminent domain: State Constitution Art. 1 s 16 (Amendment 9).
Eminent domain by cities: Chapter 8.12 RCW.