(a) All streams or other bodies of water which appear as lines to indicate natural waters on the reference maps herein, and which are not specifically designated in table I, shall be assigned the same classes and standards of quality and purity as the specifically designated waters to which they are directly tributary.

(b) All streams or other bodies of water which are not shown on the reference maps herein shall be assigned to class D, as set forth in Part 701 of this Title except that any continuous flowing natural stream which is not shown on the reference maps shall have the same class and assigned standards of quality and purity as the waters to which it is directly tributary.

(c) Notwithstanding the classifications in table I and the special conditions in subdivisions (a) and (b) of this section, waters contained within the boundaries of forest preserve lands and, therefore, controlled under the provisions of the State Constitution and the Environmental Conservation Law are hereby excluded from classification to the extent that any part of such waters may be located within the boundaries of forest preserve lands. All waters within 100 feet of a boundary of forest preserve lands but not located on forest preserve lands shall have a classification of A and be governed by the rules and regulations promulgated by the Department of Environmental Conservation, unless a higher classification has been assigned.