Iowa Code § 468.519: Levee and pumping station districts.

In levee and drainage districts having pumping stations trustees shall hold office until the fourth Saturday in January three years after election. On the third Saturday in January of each year a trustee shall be elected for a term of three years to succeed the member of the board whose term will expire on the following Saturday. At the election there shall also be elected, if necessary, a trustee to fill any vacancy which occurred before the election.