C.__Between May 15th and September 30th, the number of Escherichia coli bacteria of human origin in these waters may not exceed a geometric mean of 142 per 100 milliliters or an instantaneous level of 949 per 100 milliliters.

Sec. 3. 38 MRSA §466, sub-§8, as enacted by PL 1985, c. 698, §15, is repealed and the following enacted in its place;

8.__Indigenous.__"Indigenous" means historically or currently present naturally in the State's waters without having been brought directly or indirectly to the State's waters.

Sec. 4. 38 MRSA §466, sub-§10-A is enacted to read:

10-A.__Thermal stratification.__"Thermal stratification" means a change in temperature of at least one degree Celsius per meter of depth, causing waters below this temperature gradient to remain isolated and not to mix with waters above the temperature gradient.

Sec. 5. 38 MRSA §467, sub-§1, ķA, as affected by PL 1989, c. 890, Pt. A, §40 and amended by Pt. B, §68, is further amended to read:

A. Androscoggin River, main stem, including all impoundments.

(1) From the Maine-New Hampshire boundary to its confluence with the Ellis River - Class B.

(2) From its confluence with the Ellis River to a line formed by the extension of the Bath-Brunswick boundary across Merrymeeting Bay in a northwesterly direction Turner Bridge in Turner - Class C.

(3)__From the Turner Bridge in Turner to Gulf Island Pond Dam - Class RI.

(4)__From Gulf Island Pond Dam to a line formed by the extension of the Bath-Brunswick boundary across Merrymeeting Bay in a northwesterly direction - Class C.