Whenever the board of county commissioners of any such county shall have adjudged as provided in RCW 88.32.010, said board shall thereupon apply to the person, who, for the time being, shall be judge of the United States district court, for the district within which the county shall be situated, to name eleven reputable citizens and freeholders of such county and file a list thereof with said board of county commissioners. The persons so named, or a majority of them, shall act as a commission, and be known as the "river and harbor improvement commission of . . . . . . county", and shall receive no compensation, except their actual necessary expenses, including necessary clerical assistance, to be audited by the board of county commissioners; and they shall be deemed the agents of the county in the performance of the duties imposed upon them by RCW 88.32.010 through 88.32.220. Each member of such commission shall, before entering upon his or her duties, take and subscribe an oath, substantially as follows:

I, the undersigned, a member of the river and harbor improvement commission of . . . . . . county, to define and establish the assessment district and assess the costs of the following improvement (here give the general description of the improvement), do solemnly swear (or affirm, as the case may be), that I will well and truly discharge my duties as a member of said commission." In case the person who is United States judge shall be unable or decline to act, the board of county commissioners shall name the eleven persons to act as such commission.