Iowa Code § 468.205: Supplemental reports.

Upon the filing of such report the board shall examine and consider the same together with the plan and the commitments involved in its adoption and may require supplemental reports of the engineer or of another disinterested engineer with such data as they may deem necessary or desirable including recommendations for any change or modification, negotiate with the federal agency involved and amend the plan in such manner as may be mutually agreed upon. The engineer shall make such supplemental reports as may be required by the board or necessitated by amendment of plan.