Once the Department has, in accordance with paragraph 3 of Part I of this Schedule, assigned to a river or part thereof a Type specified in column 1 of Table 4 below, it shall apply, as applicable, the “high”, “good”, “moderate”, “poor” or “bad” reactive phosphorus standard specified in columns 2, 3, 4, 5 and 6 respectively of that Table to that river or part thereof.