It shall be the duty of the county engineer, in conformity with the regulations and requirements of the secretary of transportation to:

(1) Prepare plans and specifications and estimates for roads, bridges and culverts to be built by the county;

(2) act for the county in all matters relating to the supervision of the construction, repairing, surfacing, resurfacing and maintenance of any roads, bridges or culverts, or anything pertaining to rivers, streams or watercourses, for which the county pays any part of the cost thereof;

(3) visit and inspect the highways and culverts in each township of the county or district which have been reported as unsafe or in need of repair, and advise and direct the township board and the road overseer of each township as to the best methods of construction, repair, maintenance and improvement of such highways and culverts;

(4) prepare plans, specifications and general regulations governing the construction and maintenance of township roads and culverts, and upon request furnish copies of the same to the township board and to the road overseer of the several townships of the county or district;

(5) keep a record of all contracts and of all purchases of material, machinery or apparatus to be used in road construction, in excess of $10,000, approved by the county engineer in any township;

(6) study the soil conditions and collect information concerning the various deposits of gravel, stone, sand, clay and other road and bridge building materials, and to investigate and determine the most approved methods of using the same;

(7) make maps of the roads in the different townships of the county or district, and where there are no other records, or the records are incomplete, and when ordered by the county commissioners, the county engineer shall make maps of plats and file them in the offices of the county clerk and township clerk, which when passed upon and adopted by the board of county commissioners shall be the records of such roads where there are no other records, and shall be additional and supplemental records when the former records are incomplete or imperfect;

(8) answer inquiries and to hold at least one public meeting annually to advise with highway officials in road, bridge and culvert improvement, and to perform all other duties required by law.