(1) This chapter shall be deemed to provide an additional and alternative method for the doing of the things authorized hereby and shall be regarded as supplemental and additional to the powers conferred upon the commission by other laws, and shall not be regarded as in derogation of any powers now existing. This chapter being necessary for the welfare of the inhabitants of the several counties of the state shall be liberally construed to effect the purposes thereof.
(2) This chapter shall not repeal any local or special act or law conferring upon any of the several counties or county commissions the powers and duties or any of them imposed hereby, but it shall be deemed to be an alternative or additional method for such counties or county commissions to effect the purposes of this chapter.