Ill. Admin. Code tit. 35 § 368.230

Current through Register Vol. 48, No. 49, December 6, 2024

Section 368.230 - A2 Factor (Water Quality Potential)

a) A2 is a factor that evaluates inland lakes based on their Water Quality Potential (WQP). The potential quality of a lake is determined by the quality of the incoming water, water residence time, and lake basin characteristics. Four factors are used to rank inland lakes for water quality potential:

1) ratio of watershed area to lake surface area (WA:SA);

2) mean lake depth;

3) lake water retention time; and

4) lake size.

b) Priority points for the A2 factor are allocated as follows (0-100 points possible):

1) Watershed Area/Lake Surface Area Ratio

A) Less than or equal to 20

B) Greater than 20 but less than or equal to 50

C) Greater than 50 but less than or equal to 100

D) Greater than 100

2) Mean Depth (feet)

A) Greater than 15

B) Greater than 10 but less than or equal to 15

C) Greater than 5 but less than or equal to 10

D) Less than or equal to 5

3) Water Retention Time (years)

A) Greater than 1.00

B) Greater than 0.50 but less than or equal to 1.00

C) Greater than 0.25 but less than or equal to 0.50

D) Less than or equal to 0.25

4) Lake Size (acres)

A) Greater than 100 but less than or equal to 500

B) Greater than six but less than or equal to 100; or greater than 500 but less than or equal to 1000

C) Less than or equal to 6 or greater than 1000

Ill. Admin. Code tit. 35, § 368.230