Ill. Admin. Code tit. 77, pt. 905, app A, ILLUSTRATION M, exh. B

Current through Register Vol. 49, No. 2, January 10, 2025

Exhibit B - Key for Determining Sewage Loading Rates (Gallons/Square Foot/Day)

Structure and Parent Material

Single grain; Weak ; Platy2

Granular, Angular and Subangular Blocky; Prismatic

Structureless or Massive

Loess: Outwash; Alluvium; Lacustrine8

Till3

Week

Moderate; Strong

Strong

Moderate; Strong

Loess; Outwash; Alluvium; Lacustrine8

Till3

Moist Consistence

lo vfr fr

vfr fr

fi

vfr

fi

vfr fr

fi

fr

fi

vfi

vfr

fr

fi

vfr fr

fi vfi

Texture

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

1. Fragmental; Ext. or Very gravelly sand

> 1.004

N/A5

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

2. Sand; Loamy course sand; Loamy sand; Gravelly sand; Coarse sand; Gravelly loamy sand

1.00

1.00

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

1.00

N/A

N/A

N/A

N/A

3. Fine sand; Loamy fine sand; Coarse sandy loam

0.84

0.91

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

0.91

0.84

N/A

N/A

N/A

4. Sandy loam; Fine sandy loam; Gravelly sandy loam; Gravelly loam; Gravelly silt loam

0.75

0.75

N.A

0.84

N/A

0.69

N/A

N/A

0.75

N/A

0.84

0.75

0.69

0.62

0.52

5. Loam; Silt loam; Very fine sandy loam; Sandy clay loam; Silt; Very fine sand; Loamy very fine sand; Gravelly clay loam

0.62

0.69

0.62

0.75

0.52

0.456

0.406

0.62

0.52

N/A

0.62

0.52

0.456

0.276

N/R7

6. Silty clay loam (<35% c); Clay loam (< 35% c)

.052

0.52

0.456

0.62

0.52

0.408

0.276

0.52

0.406

0.276

0.52

0.456

0.276

N/R

N/R

7. Silty clay loam (>35% c); Clay loam (>35% c)

N/A

N/A

0.406

0.456

0.406

0.276

0.206

0.406

0.276

0.206

N/A

0.206

N/R

N/R

N/R

8. Sandy clay; Clay

N/A

N/A

N/A

N/A

0.206,9

N/A

N/A

N/A

0.206,9

N/R

N/A

N/A

N/R

N/A

N/R

9. Organics; Fragic; Lithic; Paralithic

---SOIL PROPERTIES HAVE VERY SEVERE LIMITATIONS; SUBSURFACE DISPOSAL NOT RECOMMENDED-----

FOOTNOTES:

¹ Disturbed soils are highly variable and require special on-site investigations.

² Moderate or strong platy structure for the soil textures in Groups 4, 5 and 6 have a loading rate of 0.40 g/sq.ft/d. Platy structure having firm or very firm consistency or caused by mechanical compaction has a loading rate of 0.0 g/sq.ft/d.

³ Basal glacial tills structured by geogenic processes have the same loading rates as structureless glacial till.

⁴ This soil group is estimated to have very rapid permeability and exceeds the maximum established rate in Illustration H, Exhibit A.

⁵ N/A means not applicable.

⁶ These soil groups are estimated to have moderately slow to very slow permeability and are less than the minimum established rate in Illustration H, Exhibit A.

⁷ N/R means not recommended. These soils have loading rates considered too low for conventional subsurface disposal.

⁸ In some areas, lacustrine material may have physical properties similar to glacial till and should be placed in the glacial till columns.

⁹ Non-swelling (1:1 lattice) clays formed in bedrock residuum have a loading rate of 0.27 g/sq.ft/d. Swelling (2:1 lattice) clays are not recommended for subsurface disposal.

Ill. Admin. Code tit. 77, pt. 905, app A, ILLUSTRATION M, exh. B

Amended at 37 Ill. Reg. 14994, effective August 28, 2013