Upon the receipt of any water sample sent under § 29.1-213, the State Water Control Board shall have a chemical analysis of the sample made by a chemist employed by the State Water Control Board or retained especially for that purpose. If the results of the analysis show that the sample of water was polluted, the State Water Control Board shall initiate further studies and analyses to determine the nature, extent and most effective measures of control of the pollution. The State Water Control Board shall then proceed as provided in Chapter 3.1 (§ 62.1-44.2 et seq.) of Title 62.1.