*soil borings*per site shall be conducted in accordance with Chapter 4 to determine the depth to seasonal or permanent soil saturation or bedrock. Identification of a replacement system area is not required.

TABLE 902.2

MINIMUM SOIL DEPTHS FOR MOUND SYSTEM INSTALLATION

RESTRICTING FACTOR | MINIMUM SOIL DEPTH TO RESTRICTION (inches) |

High ground water | 24 |

Impermeable rock strata | 60 |

Pervious rock | 24 |

Rock fragments (50-percent volume) | 24 |

TABLE 903.1(1)

DESIGN CRITERIA FOR A MOUND FOR A ONE-BEDROOM HOME ON A 0- TO 6-PERCENT SLOPE

WITH LOADING RATES OF 150 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL

DESIGN PARAMETER | SLOPE (percent) | ||||

0 | 2 | 4 | 6 | ||

A | Trench width, feet | 3 | 3 | 3 | 3 |

B | Trench length, feet Number of trenches | 42 1 | 42 1 | 42 1 | 42 1 |

D | Mound height, inches | 12 | 12 | 12 | 12 |

F | Mound height, inches | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 |

I | Mound width, feet^{a} | 15 | 15 | 15 | 15 |

J | Mound width, feet^{a} | 11 | 8 | 8 | 8 |

K | Mound length, feet | 10 | 10 | 10 | 10 |

L | Mound length, feet | 62 | 62 | 62 | 62 |

P | Distribution pipe length, feet | 20 | 20 | 20 | 20 |

Distribution pipe diameter, inches | 1 | 1 | 1 | 1 | |

Number of holes per distribution pipe^{b} | 9 | 9 | 9 | 9 | |

Hole spacing, inches^{b} | 30 | 30 | 30 | 30 | |

Hole diameter, inches^{b} | 0.25 | 0.25 | 0.25 | 0.25 | |

W | Mound width, feet | 25 | 26 | 26 | 26 |

TABLE 903.1 (2)

DESIGN CRITERIA FOR A TWO-BEDROOM HOME FOR A MOUND ON A 0- TO 6-PERCENT SLOPE

WITH LOADING RATES OF 300 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL

DESIGN PARAMETER | SLOPE (percent) | ||||

0 | 2 | 4 | 6 | ||

A | Trench width, feet | 3 | 3 | 3 | 3 |

B | Trench length, feet Number of trenches | 42 2 | 42 2 | 42 2 | 42 2 |

C | Trench spacing, feet | 15 | 15 | 15 | 15 |

D | Mound height, inches | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 17 | 25 | 25 |

F | Mound height, inches | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 |

I | Mound width, feet^{a } | 12 | 20 | 20 | 20 |

J | Mound width, feet | 12 | 8 | 8 | 8 |

K | Mound length, feet | 10 | 10 | 10 | 10 |

L | Mound length, feet | 62 | 62 | 62 | 62 |

P | Distribution pipe length, feet | 20 | 20 | 20 | 20 |

Distribution pipe diameter, inches | 1 | 1 | 1 | 1 | |

Number of holes per distribution pipes^{b} | 9 | 9 | 9 | 9 | |

Hole spacing, inches^{b} | 30 | 30 | 30 | 30 | |

Hole diameter, inches | 0.25 | 0.25 | 0.25 | 0.25 | |

R | Manifold length, feet Manifold diameter, inches ^{c} | 15 2 | 15 2 | 15 2 | 15 2 |

W | Mound width, feet | 42 | 46 | 46 | 46 |

TABLE 903.1(3)

DESIGN CRITERIA FOR A THREE-BEDROOM HOME FOR A MOUND ON A 0- TO 6-PERCENT SLOPE

WITH LOADING RATES OF 450 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL

DESIGN PARAMETER | SLOPE (percent) | ||||

0 | 2 | 4 | 6 | ||

A | Trench width, feet | 3 | 3 | 3 | 3 |

B | Trench length, feet Number of trenches | 63 2 | 63 2 | 63 2 | 63 2 |

C | Trench spacing, feet | 15 | 15 | 15 | 15 |

D | Mound height, inches | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 17 | 20 | 25 |

F | Mound height, inches | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 |

I | Mound width, feet^{a} | 12 | 20 | 20 | 20 |

J | Mound width, feet^{a} | 12 | 8 | 8 | 8 |

K | Mound length, feet | 10 | 10 | 10 | 10 |

L | Mound length, feet | 62 | 62 | 62 | 62 |

P | Distribution pipe length, feet Distribution pipe diameter, inches Number of holes per distribution pipe ^{b} Hole spacing ^{b}, inches Hole diameter, inches | 31 1 ^{1}/_{4} 13 30 0.25 | 31 1 ^{1}/_{4} 13 30 0.25 | 31 1 ^{1}/_{4 }13 30 0.25 | 31 1 ^{1}/_{4 }13 30 0.25 |

R | Manifold length, feet Manifold diameter, inches ^{c} | 15 2 | 15 2 | 15 2 | 15 2 |

W | Mound width, feet | 42 | 46 | 46 | 46 |

TABLE 903.1(4)

DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 6-PERCENT SLOPE WITH

LOADING RATES OF 600 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL

DESIGN PARAMETER | SLOPE (percent) | ||||

0 | 2 | 4 | 6 | ||

A | Trench width, feet | 3 | 3 | 3 | 3 |

B | Trench length, feet Number of trenches | 56 3 | 56 3 | 56 3 | 56 3 |

C | Trench spacing, feet | 15 | 15 | 15 | 15 |

D | Mound height, inches | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 20 | 28 | 36 |

F | Mound height, inches | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 |

H | Mound height, inches | 24 | 24 | 24 | 24 |

I | Mound width, feet^{a} | 12 | 20 | 20 | 20 |

J | Mound width, feet^{a } | 12 | 8 | 8 | 8 |

K | Mound length, feet | 12 | 12 | 12 | 14 |

L | Mound length, feet | 80 | 80 | 80 | 84 |

P | Distribution pipe length, feet Distribution pipe diameter, inches Number of holes per distribution pipe ^{b} Hole spacing, inches ^{b} Hole diameter, inches | 27.5 1 ^{1}/_{4} 12 30 0.25 | 27.5 1 ^{1}/_{4} 12 30 0.25 | 27.5 1 ^{1}/_{4} 12 30 0.25 | 27.5 1 ^{1}/_{4} 12 30 0.25 |

R | Manifold length, feet Manifold diameter, inches ^{c} | 30 2 | 30 2 | 30 2 | 30 2 |

W | Mound width, feet | 57 | 61 | 61 | 61 |

TABLE 903.1(5)

DESIGN CRITERIA FOR A ONE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 150 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

3 to 60 | 3 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10^{a} | 12^{a} | ||

A | Bed width, feet^{b} | 10 | 10 | 10 | 10 | 10 | 10 | 10 |

B | Bed length, feet | 13 | 13 | 13 | 13 | 13 | 13 | 13 |

D | Mound height, inches | 24 | 24 | 24 | 24 | 24 | 24 | 24 |

E | Mound height, inches | 24 | 26 | 29 | 31 | 34 | 36 | 38 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 12 | 13 | 14 | 17 | 18 | 21 | 26 |

J | Mound width, feet | 12 | 11 | 10 | 10 | 9 | 9 | 9 |

K | Mound length, feet | 12 | 12 | 12 | 13 | 13 | 13 | 15 |

L | Mound length, feet | 37 | 37 | 37 | 39 | 39 | 39 | 43 |

*(continued)*

TABLE 903.1(5)—continued

DESIGN CRITERIA FOR A ONE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 150 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK

PERCOLATION RATE (minutes per inch) SLOPE (percent) | ||||||||

DESIGN PARAMETER | 3 to 60 | 3 to less than 30 | ||||||

0 | 2 | 4 | 6 | 8 | 10^{a} | 12^{a} | ||

P | Distribution pipe length, feet^{c} Distribution pipe diameter, inches Number of distribution pipes | 12.5 1 6 | 12.5 1 6 | 12.5 1 6 | 12.5 1 6 | 12.5 1 6 | 12.5 1 6 | 12.5 1 6 |

R | Manifold length, feet Manifold diameter, inches ^{c} | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 |

S | Distribution pipe spacing, feet | 3 | 3 | 3 | 3 | 3 | 3 | 3 |

Number of holes per distribution pipe^{d} | 6 | 6 | 6 | 6 | 6 | 6 | 6 | |

Hole spacing, inches^{d} | 30 | 30 | 30 | 30 | 30 | 30 | 30 | |

Hole diameter, inches | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | |

W | Mound width, feet | 34 | 34 | 34 | 37 | 37 | 41 | 45 |

*D*) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease

*E*[downslope fill depth, feet (mm)].

TABLE 903.1(6)

DESIGN CRITERIA FOR A TWO-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 300 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

3 to 60 | 3 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 ^{a} | 12 ^{a} | ||

A | Bed width, feet^{b } | 10 | 10 | 10 | 10 | 10 | 10 | 10 |

B | Bed length, feet | 25 | 25 | 25 | 25 | 25 | 25 | 25 |

D | Mound height, inches | 24 | 24 | 24 | 24 | 24 | 24 | 24 |

E | Mound height, inches | 24 | 26 | 29 | 31 | 34 | 36 | 38 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 12 | 13 | 14 | 17 | 18 | 21 | 26 |

J | Mound width, feet | 12 | 11 | 10 | 10 | 9 | 9 | 9 |

K | Mound length, feet | 12 | 12 | 12 | 13 | 13 | 13 | 15 |

L | Mound length, feet | 49 | 49 | 49 | 51 | 51 | 51 | 55 |

P | Distribution pipe length, feet^{c} Distribution pipe diameter, inches Number of distribution pipes | 12 1 6 | 12 1 6 | 12 1 6 | 12 1 6 | 12 1 6 | 12 1 6 | 12 1 6 |

R | Manifold length, feet Manifold diameter, inches | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 |

S | Distribution pipe spacing, feet Number of holes per distribution pipe ^{d} Hole spacing, inches ^{d} Hole diameter, inches | 3 5 30 0.25 | 3 5 30 0.25 | 3 5 30 0.25 | 3 5 30 0.25 | 3 5 30 0.25 | 3 5 30 0.25 | 3 5 30 0.25 |

W | Mound width, feet | 34 | 34 | 34 | 37 | 37 | 41 | 45 |

*D*) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease

*E*[downslope fill depth, feet (mm)].

TABLE 903.1(7)

DESIGN CRITERIA FOR A THREE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE

WITH LOADING RATES OF 450 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

3 to 60 | 3 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10^{a} | 12^{a} | ||

A | Bed width, feet^{b} | 10 | 10 | 10 | 10 | 10 | 10 | 10 |

B | Bed length, feet | 38 | 38 | 38 | 38 | 38 | 38 | 38 |

D | Mound height, inches | 24 | 24 | 24 | 24 | 24 | 24 | 24 |

E | Mound height, inches | 24 | 26 | 29 | 31 | 34 | 36 | 38 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 12 | 13 | 14 | 17 | 18 | 21 | 26 |

J | Mound width, feet | 12 | 11 | 10 | 10 | 9 | 9 | 9 |

K | Mound length, feet | 12 | 12 | 12 | 13 | 13 | 13 | 15 |

L | Mound length, feet | 62 | 62 | 62 | 64 | 64 | 64 | 68 |

P | Distribution pipe length, feet^{c} Distribution pipe diameter, inches Number of distribution pipes | 18.5 1 6 | 18.5 1 6 | 18.5 1 6 | 18.5 1 6 | 18.5 1 6 | 18.5 1 6 | 18.5 1 6 |

R | Manifold length, feet Manifold diameter, inches | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 |

S | Distribution pipe spacing, feet Number of holes per distribution pipe ^{d} Hole spacing, inches ^{d} Hole diameter, inches | 3 8 30 0.25 | 3 8 30 0.25 | 3 8 30 0.25 | 3 8 30 0.25 | 3 8 30 0.25 | 3 8 30 0.25 | 3 8 30 0.25 |

W | Mound width, feet | 34 | 34 | 34 | 37 | 37 | 41 | 45 |

*D*) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease

*E*[downslope fill depth, feet (mm)].

TABLE 903.1(8)

DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 600 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

3 to 60 | 3 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10^{a} | 12^{a} | ||

A | Bed width, feet^{b} | 10 | 10 | 10 | 10 | 10 | 10 | 10 |

B | Bed length, feet | 50 | 50 | 50 | 50 | 50 | 50 | 50 |

D | Mound height, inches | 24 | 24 | 24 | 24 | 24 | 24 | 24 |

E | Mound height, inches | 24 | 26 | 29 | 31 | 34 | 36 | 38 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 12 | 13 | 14 | 17 | 18 | 21 | 26 |

J | Mound width, feet | 12 | 11 | 10 | 10 | 9 | 9 | 9 |

K | Mound length, feet | 12 | 12 | 12 | 13 | 13 | 13 | 15 |

L | Mound length, feet | 74 | 74 | 74 | 76 | 76 | 76 | 78 |

P | Distribution pipe length, feet^{c} Distribution pipe diameter, inches Number of distribution pipes | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 |

R | Manifold length, feet Manifold diameter, inches | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 |

S | Distribution pipe spacing, feet Number of holes per distribution pipe ^{d} Hole spacing, inches ^{d} Hole diameter, inches | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 |

W | Mound width, feet | 34 | 34 | 34 | 37 | 37 | 41 | 45 |

*D)*shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease

*E*[downslope fill depth, feet (mm)].

TABLE 903.1(9)

DESIGN CRITERIA FOR A ONE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 150 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

0 to 60 | 0 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 | 12 | ||

A | Bed width, feet | 4 | 4 | 4 | 4 | 4 | 4 | 4 |

B | Bed length, feet | 32 | 32 | 32 | 32 | 32 | 32 | 32 |

D | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 13 | 14 | 14 | 16 | 17 | 18 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 9 | 10 | 11 | 12 | 13 | 14 | 15 |

J | Mound width, feet | 9 | 9 | 8 | 8 | 7 | 7 | 6 |

*(continued)*

TABLE 903.1(9)—continued

DESIGN CRITERIA FOR A ONE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 150 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

0 to 60 | 0 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 | 12 | ||

K | Mound length, feet | 10 | 10 | 10 | 10 | 10 | 11 | 11 |

L | Mound length, feet | 52 | 52 | 52 | 52 | 52 | 53 | 53 |

P | Distribution pipe length | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 |

Distribution pipe diameter, inches | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |

Number of distribution pipes | 2 | 2 | 2 | 2 | 2 | 2 | 2 | |

Number of holes per distribution pipe^{a} | 7 | 7 | 7 | 7 | 7 | 7 | 7 | |

Hole spacing, inches^{a} | 30 | 30 | 30 | 30 | 30 | 30 | 30 | |

Hole diameter, inches | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | |

W | Mound width, feet | 22 | 23 | 23 | 24 | 24 | 25 | 25 |

TABLE 903.1(10)

DESIGN CRITERIA FOR A TWO-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 300 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

0 to 60 | 0 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 | 12 | ||

A | Bed width, feet | 6 | 6 | 6 | 6 | 6 | 6 | 6 |

B | Bed length, feet | 42 | 42 | 42 | 42 | 42 | 42 | 42 |

D | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 13 | 14 | 17 | 18 | 19 | 22 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 9 | 10 | 11 | 12 | 13 | 15 | 16 |

J | Mound width, feet | 9 | 9 | 8 | 8 | 7 | 7 | 6 |

K | Mound length, feet | 10 | 10 | 10 | 10 | 10 | 11 | 11 |

L | Mound length, feet | 62 | 62 | 62 | 62 | 62 | 64 | 64 |

P | Distribution pipe length, feet^{a} Distribution pipe diameter, inches Number of distribution pipes | 20 1 4 | 20 1 4 | 20 1 4 | 20 1 4 | 20 1 4 | 20 1 4 | 20 1 4 |

R | Manifold length, feet Manifold diameter, inches | 3 2 | 3 2 | 3 2 | 3 2 | 3 2 | 3 2 | 3 2 |

S | Distribution pipe spacing, feet Number of holes per distribution pipe ^{b} Hole spacing, inches ^{b} Hole diameter, inches | 3 9 30 0.25 | 3 9 30 0.25 | 3 9 30 0.25 | 3 9 30 0.25 | 3 9 30 0.25 | 3 9 30 0.25 | 3 9 30 0.25 |

W | Mound width, feet | 24 | 25 | 25 | 26 | 26 | 28 | 29 |

TABLE 903.1(11)

DESIGN CRITERIA FOR A THREE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 450 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

0 to 60 | 0 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 | 12 | ||

A | Bed width, feet | 8 | 8 | 8 | 8 | 8 | 8 | 8 |

B | Bed length, feet | 47 | 47 | 47 | 47 | 47 | 47 | 47 |

D | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 12 | 16 | 18 | 19 | 22 | 24 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 9 | 11 | 12 | 13 | 15 | 17 | 18 |

J | Mound width, feet | 9 | 9 | 8 | 8 | 7 | 7 | 6 |

K | Mound length, feet | 10 | 10 | 10 | 10 | 10 | 11 | 12 |

L | Mound length, feet | 67 | 67 | 67 | 67 | 69 | 69 | 71 |

P | Distribution pipe length, feet Distribution pipe diameter, inches Number of distribution pipes | 23 1 6 | 23 1 6 | 23 1 6 | 23 1 6 | 23 1 6 | 23 1 6 | 23 1 6 |

R | Manifold length, feet Manifold diameter, inches | 64 2 | 64 2 | 64 2 | 64 2 | 64 2 | 64 2 | 64 2 |

S | Distribution pipe spacing, feet Number of holes per distribution pipe ^{a} Hole spacing, inches ^{a} Hole diameter, inches | 32 10 30 0.25 | 32 10 30 0.25 | 32 10 30 0.25 | 32 10 30 0.25 | 32 10 30 0.25 | 32 10 30 0.25 | 32 10 30 0.25 |

W | Mound width, feet | 26 | 28 | 28 | 29 | 30 | 32 | 32 |

TABLE 903.1(12)

DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 600 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

0 to 60 | 0 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 | 12 | ||

A | Bed width, feet | 10 | 10 | 10 | 10 | 10 | 10 | 10 |

B | Bed length, feet | 50 | 50 | 50 | 50 | 50 | 50 | 50 |

D | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

E | Mound height, inches | 12 | 14 | 17 | 19 | 22 | 24 | 26 |

F | Mound height, inches | 9 | 9 | 9 | 9 | 9 | 9 | 9 |

G | Mound height, inches | 12 | 12 | 12 | 12 | 12 | 12 | 12 |

H | Mound height, inches | 18 | 18 | 18 | 18 | 18 | 18 | 18 |

I | Mound width, feet | 9 | 11 | 13 | 14 | 17 | 18 | 19 |

J | Mound width, feet | 9 | 9 | 8 | 8 | 7 | 7 | 6 |

K | Mound length, feet | 10 | 10 | 10 | 10 | 11 | 11 | 12 |

L | Mound length, feet | 70 | 70 | 70 | 70 | 72 | 72 | 74 |

*(continued)*

TABLE 903.1(12)—continued

DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH

LOADING RATES OF 600 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE

DESIGN PARAMETER | PERCOLATION RATE (minutes per inch) SLOPE (percent) | |||||||

0 to 60 | 0 to less than 30 | |||||||

0 | 2 | 4 | 6 | 8 | 10 | 12 | ||

P | Distribution pipe length, feet Distribution pipe diameter, inches Number of distribution pipes | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 | 24.5 1 6 |

R | Manifold length, feet Manifold diameter, inches | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 | 6 2 |

S | Distribution pipe spacing, feet Number of holes per distribution pipe ^{a} Hole spacing, inches ^{a} Hole diameter, inches | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 | 3 10 30 0.25 |

W | Mound width, feet | 28 | 29 | 31 | 32 | 34 | 35 | 36 |

A | = | Bed or trench width, feet (mm). |

A_{A} | = | Required absorption area, square feet (m^{2}). |

B | = | Bed or trench length, feet (mm). |

B_{A} | = | Basal area, square feet (m^{2}). |

C | = | Trench spacing, feet (mm). |

C_{I} | = | Infiltration capacity of natural soil, gallons per foot per day (L/mm/day). |

D | = | Fill depth, feet (mm). |

E | = | Downslope fill depth, feet (mm). |

F | = | Bed or trench depth, feet (mm). |

G | = | Minimum cap and topsoil depth, feet (mm). |

H | = | Cap and topsoil depth at center of mound, foot (mm). |

I | = | Downslope width, feet (mm). |

J | = | Upslope width, feet (mm). |

K | = | End slope length, feet (mm). |

L | = | Total mound length, feet (mm). |

N | = | Number of trenches. |

P | = | Distribution pipe length, feet (mm). |

R | = | Manifold length, feet (mm). |

S | = | Distribution pipe spacing, feet (mm). |

S_{D} | = | Downslope correction factor. |

S_{U} | = | Upslope correction factor. |

T_{W} | = | Total daily waste-water flow, gallons per day (L/day). |

W | = | Total mound width, feet (mm). |

X | = | Slope, percent. |

^{2}) per day. The required absorption area shall be determined by the following equation:

(Equation 9-1) |

^{2}, 1 gallon = 3.785 L.

*B*) shall be not more than 100 feet (2540 mm). Trenches shall be of equal length where more than one trench is required. A mound shall not have more than three trenches. Trench spacing (

*C*) shall be determined by the following equation:

(Equation 9-2) |

^{2}.

The calculated trench spacing (*C*) shall be measured from center to center of the trenches. Facilities with more than 1,500 gallons (56 775 L) per day shall be specifically engineered and approved for use with a trench system.

*D*) shall be not less than 1 foot (305 mm) for slowly permeable soils and permeable soils with high water tables and not less than 2 feet (610 mm) of fill shall be required for shallow permeable soils over bedrock. Additional fill shall be placed at the downslope end of the bed or trench where the site is not level so the bottom of the bed or trenches is level. The downslope fill depth for bed systems shall be determined by the following equation:

E = D + XA | (Equation 9-3) |

For SI: 1 foot = 304.8 mm.

The downslope fill depth for trench systems shall be determined by the following equation:

E = D + X (C + A) | (Equation 9-4) |

For SI: 1 foot = 304.8 mm.

*H*) at the center of the mound shall be not less than 18 inches (457 mm), which includes 1 foot (305 mm) of subsoil and 6 inches (152 mm) of topsoil. Outer edges of the mound,

*G*(the minimum cap and topsoil depth), shall be not less than 1 foot (305 mm), which includes 6 inches (152 mm) of subsoil and 6 inches (152 mm) of topsoil. The soil used for the cap shall be topsoil or finer textured subsoil.

*L*) shall be determined by the following equation:

L = B + 2K | (Equation 9-5) |

For SI: 1 foot = 304.8 mm.

where:

W = J + A + I | (Equation 9-6) |

For SI: 1 foot = 304.8 mm.

(Equation 9-7) |

For SI: 1 foot = 304.8 mm.

where:

*J *= 3(*D* + *F* + *G*)*S _{U }*

*I *= 3(*E* + *F* + *G*)*S _{D}*

*S*) and the downslope correction factor (

_{U}*S*) shall be determined based on the slope in accordance with Table 903.5.5.

_{D}TABLE 903.5.5

DOWNSLOPE AND UPSLOPE WIDTH CORRECTIONS

FOR MOUNDS ON SLOPING SITES

SLOPE (percent) | DOWNSLOPE CORRECTION FACTOR ( S)_{D} | UPSLOPE CORRECTION FACTOR ( S)_{U} |

0 | 1 | 1 |

1 | 1.03 | 0.97 |

2 | 1.06 | 0.94 |

3 | 1.10 | 0.915 |

4 | 1.14 | 0.89 |

5 | 1.18 | 0.875 |

6 | 1.22 | 0.86 |

7 | 1.27 | 0.83 |

8 | 1.32 | 0.80 |

9 | 1.38 | 0.785 |

10 | 1.44 | 0.77 |

11 | 1.51 | 0.75 |

12 | 1.57 | 0.73 |

(Equation 9-8) |

For SI: 1 square foot = 0.0929 m^{2}.

The infiltrative capacity of natural soil shall be determined on the percolation rate in accordance with Table 903.6.

TABLE 903.6

INFILTRATIVE CAPACITY OF NATURAL SOIL

PERCOLATION RATE (minutes per inch) | INFILTRATIVE CAPACITY (gallons per foot per day) |

Less than 30 | 1.2 |

30 to 60 | 0.74 |

More than 60 to 120 | 0.24 |

BB_{A} = ( A + I) for sloping sites | (Equation 9-9) |

B for level sites_{A }= BW | (Equation 9-10) |

^{2}.

for sloping sites | (Equation 9-11) |

for level sites | (Equation 9-12) |

^{2}.

*I*) on a sloping site shall be increased or the upslope width (

*J*) and downslope (

*I*) widths on a level site shall be increased until sufficient area is available if the basal area available is not equal to or greater than the basal area required.

^{1}/

_{2}inch to 2

^{1}/

_{2}inches (12.7 mm to 64 mm) and not less than 4 inches to 5 inches (102 mm to 127 mm) of uncompacted straw or marsh hay or approved synthetic fabric shall be placed over the aggregate. Cap and topsoil covers shall be in place and the mound shall be seeded immediately and protected from erosion.