Sec. 63.160. DUTIES OF ENGINEER. The engineer shall: (1) make necessary surveys, examinations, investigations, maps, plans, and drawings relating to proposed improvements; (2) estimate the cost of improvements; (3) supervise the work of improvements; and (4) perform any duties which might be required by the commission. Acts 1971, 62nd Leg., p. 110, ch. 58, Sec. 1, eff. Aug. 30, 1971.