Iowa Code § 468.240
The board of a county with a population of two hundred thousand persons or more that has established a drainage district located partly within the corporate limits of a city may expend federal grants or revenue sharing money or other funds not derived from local tax levies in amounts as the board deems proper to pay any part of the cost of improvements authorized in this subchapter, parts 1 through 5. The board may issue general obligation bonds to pay any part of the cost of improvements authorized in this subchapter, parts 1 through 5. The bonds shall be issued according to the provisions of chapter 384, subchapter III, relating to general obligation bonds for essential corporate purposes.
Iowa Code § 468.240
89 Acts, ch 126, §2 2018 Acts, ch 1041, §127