The secretary of agriculture is hereby authorized to employ a chief engineer of the division of water resources and such expert assistants, clerical and other help as may be necessary to properly carry out the provisions of this act, and to fix their compensation. The chief engineer shall be under the classified service of the Kansas civil service act, but any vacant position of such expert assistants, clerical and other help necessary to carry out the provisions of this act may be converted by the secretary of agriculture to an unclassified position.