Iowa Code § 161E.2: Federal aid.

A county may, in accordance with this chapter, accept federal funds for aid in a project for flood or soil erosion control, flood prevention, or the conservation, development, utilization, and disposal of water, and may cooperate with the federal government or a department or agency of the federal government, a soil and water conservation district, subdistrict of a soil and water conservation district, political subdivision of the state, or other local agency, and the county may assume a proportion of the cost of the project as deemed appropriate, and may assume the maintenance cost of the project on lands under the control or jurisdiction of the county which will not be discharged by federal aid or grant.