69. The vulnerability of surface water used for category 1 water withdrawals must be rated as high, medium or low by the person responsible for withdrawals, for each of the following indicators, defined in Schedule IV:(1) physical integrity of the withdrawal site;
(2) vulnerability to microorganisms;
(3) vulnerability to fertilizers;
(4) vulnerability to turbidity;
(5) vulnerability to inorganic substances;
(6) vulnerability to organic substances.