The activities or functions of the county shall, with the exceptions herein provided, be distributed among the following general divisions or departments:
The board may establish any of the following additional departments, and such other departments as it deems necessary to the proper conduct of the business of the county:
Any activity which is unassigned by this form of county organization and government shall, upon recommendation of the county executive, be assigned by the board to the appropriate department. The board may further, upon recommendation of the county executive, reassign, transfer, rename or combine any county functions, activities or departments.
Va. Code § 15.2-518