(a) The executive and administrative powers, authority and duties in cities and towns adopting this form of government shall be distributed among three (3) departments, as follows:
(i) Department of public affairs and safety, to be administered by the mayor;
(ii) Department of accounts, finance, parks and public property, to be administered by the commissioner of finances and public property;
(iii) Department of streets and public improvements, to be administered by the commissioner of streets and public improvements.