The county engineer shall have the following duties:
(1) Prepare plans, specifications and estimates of all engineering work undertaken by the county.
(2) As necessary, furnish the county commissioners with reports, information or estimates on work.
(3) In general, perform all duties with reference to any county engineering work as the county commissioners may prescribe.
(4) Perform all duties relating to surveying as may be assigned by the county commissioners or by law.