Wash. Rev. Code § 53.34.180
Any public agency, including without limitation the department of transportation, may contract with a port district that is constructing a project or projects under this chapter for the contribution of moneys or real or personal property in aid of the construction of the projects, or for the furnishing of engineering, legal, police, and fire protection, and all other services necessary or convenient to the acquisition, construction, reconstruction, operation, maintenance, renewal, replacement, improvement, additions to, or extension of the project or projects. The contracts shall run for such period of years and contain such terms and conditions as the parties thereto mutually agree upon. Any public agency, by resolution, may authorize the execution of the contracts with a port district and no other authorization on the part of the public agency is necessary, regardless of any provision of laws or of a city charter to the contrary. Obligations assumed by a public agency under the contracts entered into under this chapter shall be included and provided for in each annual budget of the public agency made thereafter until all the obligations have been fully discharged.
RCW 53.34.180