OSS RULES TRAINING CONTROLLED FILL MOUNDS – JAN 2006 : OSS RULES TRAINING CONTROLLED FILL MOUNDS – JAN 2006 Chapter 420-3-1-.67
MOUND COMPONENTS : MOUND COMPONENTS Treatment Tank
Pump Chamber w/ Effluent Pump, Controls and Alarms
Mound [ bed ] of Fill Material [ s, ls, sl ] w/gravel for effluent distribution lines
Low Pressure, Small Diameter Distribution Piping [ edf ]
Cap of Proper Material
Prepared Layer of Original Soil
MOUND SYSTEMS Slope/Surface Requirements [ Site ] : MOUND SYSTEMS Slope/Surface Requirements [ Site ] Wisconsin Design: Dependent on Installer Accessibility [ Ala. Rules : =/< 40% ]
UNC Design: =/< 10%
Both Designs:
avoid depression/drainage area
divert/intercept surface/subsurface water
locate edf at elevation higher than pump chamber
MOUND SYSTEMS Construction : MOUND SYSTEMS Construction Protect Site Integrity
Prohibit:
site compaction
topsoil removal
working during wet conditions Prepare the Site
cut trees
clear brush
cover boulders
cut vegetation
.67(1)(b)10
MOUND SYSTEMS Construction : MOUND SYSTEMS Construction Scarify [break up] Original Soil
6 – 8 inch depth
moisture range satisfactory
soil crumbles rather than beads
use proper equipment
chisel teeth attached to backhoe
chisel plow
bucket with short teeth
** rototillers are not recommended
.67(1)(b)10
MOUND SYSTEMS Construction : MOUND SYSTEMS Construction Placement of Fill Material – Basal Area
protect scarified area
fill placed on scarified area ASAP
fill placed in lifts
fill placed from “up slope” side
fill applied [off mound] w/backhoe
work on the mound by use of crawler tractor/tracked equipment
create a gradual boundary between the fill and original soil
CONTROLLED FILL REQUIREMENTS FOR NEW RULES : CONTROLLED FILL REQUIREMENTS FOR NEW RULES Design Calculations Established/Defined
Terms defined
Perc table expanded for sizing EDFs with 4”pipe/gravel
Loading rates and correction factors established use with LPP designs [soil loading rates, linear loading rates for site conditions, slope correction factors]
Minimum standards for side/end slopes, separation distances from sidewalls to side/end slopes, etc.
Minimum standards for high certain high shrink/swell soils
Fill Placement / Bed Construction Standards
Allowable Reductions Established
Five Basic Design Modes for Approval by LHD
3 DESIGN “AREAS” of CF : 3 DESIGN “AREAS” of CF
Distribution Area (DA), Absorption Area (AA), and Basal Area (BA) – End View : Distribution Area (DA), Absorption Area (AA), and Basal Area (BA) – End View DA -The area formed by the EDF footprint
AA – The area formed by the DA plus the required setbacks from the side and end slopes
5’ for large diameter pipe
2’ for small diameter pipe
BA – The entire “footprint” of the Controlled Fill bed over the natural ground surface
For small diameter pipe and drip, it is calculated on the original ground soil loading rate
For other pipe, it is calculated on the soil test results and the amount of pipe required, with no reductions given for the type of pipe used
Distribution Area (DA), Absorption Area (AA), and Basal Area (BA) – Side View : Distribution Area (DA), Absorption Area (AA), and Basal Area (BA) – Side View DA -The area formed by the EDF footprint
AA – The area formed by the DA plus the required setbacks from the side and end slopes
5’ for large diameter pipe
2’ for small diameter pipe
BA – The entire “footprint” of the Controlled Fill bed over the natural ground surface
For small diameter pipe and drip, it is calculated on the original ground soil loading rate
For other pipe, it is calculated on the soil test results and the amount of pipe required, with no reductions given for the type of pipe used
CF Designs for LHD Approval : CF Designs for LHD Approval Five Basic Design Concepts
4 inch pipe [other large diameter], in trenches, with 12” gravel; primary treatment
4 inch pipe [other large diameter], in trenches, with 12” gravel; secondary treatment
Small diameter pipe [LPP system], in a bed, with 9” gravel; primary treatment
Small diameter pipe [LPP system], in a bed, with 9” gravel; secondary treatment
Drip tube, 6” into fill; secondary treatment
CONTROLLED FILL CALCULATIONS FOR DESIGNS USING LARGE DIAMETER PIPE : CONTROLLED FILL CALCULATIONS FOR DESIGNS USING LARGE DIAMETER PIPE Determine Height of Fill Material
Bottom of trench located as required above restrictive layer
Minimum of 12” from b.o.t. to top of gravel
Minimum of 12” of cover over pipe
Determine Perc Rate of Original Soil at 12”
Determine Amount of EDF Required
Table 3 or 3a
Determine Layout of EDF [Rectangular] - DA
3’ wide trenches
5’ between trench sidewalls
Allow for Setbacks from Side/End Slopes – AA
5’ for large diameter pipe
2’ for small diameter pipe
Determine Side/End Slopes Length
Maximum 3:1 ratio
DA for CF Using Large Diameter Pipe : DA for CF Using Large Diameter Pipe
Perc Tables : Perc Tables Review of Current Tables
Rules: 1 – 60 min/inch
Mound Manuals: up to 120 min/inch
Alternating Field Formula: up to 120 min/inch
Drip Charts: >120 min/inch
New Rules
Table 3: up to 120 min/inch
Conventional OSS
Table 3a: 121 – 240 min/inch
High Shrink-Swell Soils and Poorly Structured Soils
Minimum Design Rate of 180 min/inch in Vertisols & vertic soils
CONTROLLED FILL CALCULATIONS Large Diameter Pipe : CONTROLLED FILL CALCULATIONS Large Diameter Pipe Determine Height of Fill
Depth of trench bottom above restrictive layer
12”, 18”, 24”
Minimum of 12” from B.O.T. to top of gravel
Minimum of 12” of cover over pipe
Determine Side/End Slopes Length
Maximum 3:1 Slope
Determine Perc Rate of Original Soil at 12”
Determine Amount of EDF Required
Table 3 or 3a
Determine Layout of EDF [Rectangular]
This is the CF Bed Distribution Area [DA]
3’ wide trenches are standard
5’ minimum between trench sidewalls
Allow for Setbacks from Side/End Slopes
This, added to the DA is Absorption Area [AA]
2’ for small diameter pipe
5’ for all others
Basal Area = Total Length x Total Width
CONTROLLED FILL CALCULATIONS Large Diameter Pipe : CONTROLLED FILL CALCULATIONS Large Diameter Pipe Determine Height of Fill
Depth of trench bottom above restrictive layer
Minimum of 12” from B.O.T. to top of gravel
Minimum of 12” of cover over pipe
Determine Perc Rate of Original Soil at 12”
Determine Amount of EDF Required
Table 3 or 3a
Determine Layout of EDF [Rectangular]
This is the CF Bed Distribution Area [DA]
3’ wide trenches are standard
5’ minimum between trench sidewalls
Allow for Setbacks from Side/End Slopes
This, added to the DA is Absorption Area [AA]
Determine Side/End Slopes Length
Maximum 3:1 Slope
Basal Area = Total Length x Total Width
Layout Configurations Using 4 inch Pipe with Gravel 3 bdrm dwelling; flat lot; ASHES @ 12”; perc of 90 @ 12” 450 LF of EDF : Layout Configurations Using 4 inch Pipe with Gravel 3 bdrm dwelling; flat lot; ASHES @ 12”; perc of 90 @ 12” 450 LF of EDF Boxed Ends as part of EDF
DA = 2807 ft2; AA = 4059 ft2; BA = 6312 ft2
Header as part of EDF
DA = 2978.5ft2; AA = 4279.5ft2; BA = 6606 ft2
Center manifold as part of EDF
DA = 3010 ft2; AA = 4320 ft2; BA = 6660 ft2
Center manifold; not part of EDF
DA = 3150 ft2; AA = 4500 ft2; BA = 6900 ft2
Header; not part of EDF
DA =3202.5 ft2; AA = 4567.5 ft2; BA = 6990 ft2
Example of “Connector” Trench at End of Lines : Example of “Connector” Trench at End of Lines
LARGE DIAMETER PIPE IN CONTROLLED FILL : LARGE DIAMETER PIPE IN CONTROLLED FILL Points to Remember
BA reductions not given for type of pipe used
Large diameter pipe to be used in trenches
Designs utilizing large diameter pipe in gravel bed must be reviewed at State level
Reductions in required separation from limiting zone may by BE GIVEN FOR ALL PIPES if effluent is pre-treated to secondary levels
CF Designs on Other Restrictive Sites : CF Designs on Other Restrictive Sites Minimum Above Ground Height of Trench Bottom
6”; trench bottoms not located at <6” [.67(1)(d)]
Pre-Treatment (Secondary Standards) Required:
Sites with <6 inches to ASHES [.67(1)(e)] (Average Seasonal High Extended Saturation)
Sites with <6 inches to ASHES [.67(1)(e)] (Average Seasonal High Extended Saturation)
Sites with <12 inches to Rock [.67(1)(f)]
DESIGN EXAMPLE #1 3 bdrm. dwelling; flat lot; ASHES @12”; perc @ 12” = 90 min / inch : DESIGN EXAMPLE #1 3 bdrm. dwelling; flat lot; ASHES @12”; perc @ 12” = 90 min / inch CALCULATE HEIGHT OF FILL
B.O.T [ Table 15 ]
B.O.T. + 12” [pipe/gravel] + 12”cover
DETERMINE SIDE/END SLOPES
33.3% maximum slope [3:1]
CALCULATE EDF AMOUNT
Table 3
DETERMINE EDF LAYOUT
Rectangular
DETERMINE DA
DETERMINE AA
5’ setback on all sides
DETERMINE BASAL AREA
L = AA(L) + ES
W = AA(W) + SS
HEIGHT = 30” above NGS
[BOT] 6” + 12” + 12” = 30” above ngs
90” / 12” = 7.5’ per side / end
3 x 30” = 90“
150’ / 3’ per bedroom
450 LF of 3’ trench
5 x 77. 2’ lines + ends [ 2 x 32’]
386’ + 64’ = 450 LF
DA = 80.2’ x 35’ = 2807 ft2
Includes 1.5’ on each end
AA = 90.2’ x 45’ = 4059 ft2
[80.2’+10’] x [35’ + 10’]
BA = 105.2’ x 60’ = 6312 ft2
[90.2’+15”] x [35’ + 15’]
Examples: Five CF Designs with Minimum Standards for LHD Approval (Design Examples based on: 3 bdrm. dwelling; level lot; 450 gpd; restrictive layer at 12”; perc at 12” equal to 90 min/inch) : Examples: Five CF Designs with Minimum Standards for LHD Approval (Design Examples based on: 3 bdrm. dwelling; level lot; 450 gpd; restrictive layer at 12”; perc at 12” equal to 90 min/inch) 4 inch pipe, in trenches, with 12” gravel; primary treatment [all figures are minimum]
EDF Pipe: 450 lin.ft. in 3’ trenches
5 lines: each 77.2’ long
connection trenches on each end; each 32’ long
DA Size: 2,807 ft2 (Appr. 80.2’ x 35’)
AA Size: 4,059 ft2 (Appr. 90.2’ x 45’) – 5’ setbacks
BA Size: 6,312 ft2 (Appr. 105.2’ x 60’)
B.O.T.= 6”above natural ground, + 12” w/pipe and gravel; + 12” cover = 30” above NGS
3:1 slope @ 30” (2.5’) height = Appr. 7.5’ length on each side/end
DESIGN EXERCISE #1a 3 bdrm. dwelling; flat lot; ASHES @12”; perc @ 12” = 90 min / inch; Pre-treatment of effluent to Secondary Standards : DESIGN EXERCISE #1a 3 bdrm. dwelling; flat lot; ASHES @12”; perc @ 12” = 90 min / inch; Pre-treatment of effluent to Secondary Standards CALCULATE HEIGHT OF FILL
B.O.T [ Table 13a & .67 (1) (d) ]
B.O.T. + 12” [pipe/gravel] + 12”cover
DETERMINE SIDE/END SLOPES
33.3% [3:1] maximum slope
CALCULATE EDF AMOUNT
Table 3
Apply allowed reduction
DETERMINE EDF LAYOUT
Rectangular
DETERMINE DA
DETERMINE AA
5’ setback on all sides
DETERMINE BASAL AREA
L = AA(L) + ES
W = AA(W) + SS
B.O.T. = 6” above NGS [.67(1)(d)]
6” + 12” + 12” = 30” above ngs
90” / 12” = 7.5’ per side slope
150’ / 3’ per bedroom
450 LF of 3’ trench
450 - 20% reduction = 360 LF
4 x 78’ lines + ends [ 2 x 24’]
312’ + 48’ = 360 LF
DA = 81’ x 27’ = 2187 ft2
Includes 1.5’ on each end/side
AA = 91’ x 37’ = 3367 ft2
[81’+10’] x [27’ + 10’]
BA = 106’ x 52’ = 5512 ft2 NO
Primary treatment = 6312 ft2[105.2x60]
6312 / 106 = 59.55’; - 37’=22.55’
22.55’ / 2 = 11.275’ [135”] per side
135” / 30” = 4.5 Slope = 1:4.5 [<25%]
BA = 106 x 59.55 = 6312.3 ft2 YES
Examples: Five CF Designs with Minimum Standards for LHD Approval (Design Examples based on: 3 bdrm. dwelling; level lot; 450 gpd; restrictive layer at 12”; perc at 12” equal to 90 min/inch) : Examples: Five CF Designs with Minimum Standards for LHD Approval (Design Examples based on: 3 bdrm. dwelling; level lot; 450 gpd; restrictive layer at 12”; perc at 12” equal to 90 min/inch) 4 inch pipe, in trenches, with 12” gravel; secondary treatment [all figures are minimum] – Appr. 20% reduction in EDF
EDF Pipe: 360 lin.ft. in 3’ trenches [minimum of 360’ req’d]
4 lines: each 78’ long
connection lines on each end; each 24’ long
DA Size: 2,187 ft2 (Appr. 81’x 27’)
AA Size: 3,367 ft2 (Appr. 91’x 37’) – 5’ setbacks
BA Size: 6,312 ft2 (Appr. 106’x 59.55’)
B.O.T.= 6”above natural ground, + 12” w/pipe and gravel; + 12” cover = 30” above NGS
3:1 slope @ 30” (2.50’) height = Appr. 7.5’ length on each end
4.5:1 slope @ 30’ height = Appr. 11.275’ length on each side
CF Designs for LHD Approval : CF Designs for LHD Approval Five Basic Designs
4 inch pipe [other large diameter], in trenches, with 12” gravel; primary treatment
4 inch pipe [other large diameter], in trenches, with 12” gravel; secondary treatment
Small diameter pipe [LPP system], in a bed, with 9” gravel; primary treatment
Small diameter pipe [LPP system], in a bed, with 9” gravel; secondary treatment
Drip tube, 6” into fill; secondary treatment
Design Standards for CF Utilizing Low Pressure Pipe [LPP] : Design Standards for CF Utilizing Low Pressure Pipe [LPP] Linear Loading Rate [LLR]
An estimation of the amount of effluent (gpd) that will be dispersed along each linear foot of LPP. Dependent on:
direction of flow away from CF bed
underlying soils
surface slope
amount of flow away from CF bed
Slope Correction Factor
Applied when CF installed on non-level sites
LINEAR LOADING RATE CONCEPT OF LPP IN CONTROLLED FILL [Subjective in Nature] : LINEAR LOADING RATE CONCEPT OF LPP IN CONTROLLED FILL [Subjective in Nature] Loading rate will be high [ 8-10 gpd per LF of pipe ] when site has Slight Limitations
Loading rate will be lower [ 6-8 gpd per LF of pipe ] when site has Moderate Limitations
Loading rate will be very low [ 3-4 gpd per LF of pipe ] when site has Severe Limitations [slope, shallow depth to limiting factor (rock, water, restrictive soils), etc.], resulting in a long, narrow bed
SLOPE CORRECTION TABLE : SLOPE CORRECTION TABLE For Controlled Fill bed using small diameter LPP only
Incorporates correction factors for up slope and down slope sizing
Design Standards for CF Utilizing Low Pressure Pipe [LPP] : Design Standards for CF Utilizing Low Pressure Pipe [LPP] Fill Material Loading Rate
Tables 11 and 13
Loading Rate by Fill Type
Basal Area Loading Rate
Table 12
Loading Rate of Uppers Horizons of Original Ground under the CF Bed
OTHER DESIGN LOADING RATES FOR LPP [Low Pressure Pipe] in CONTROLLED FILL : OTHER DESIGN LOADING RATES FOR LPP [Low Pressure Pipe] in CONTROLLED FILL Fill Material Loading Rates – Tables 11&13
Sand: 1.0 gpd / ft2 [primary effluent]; 2.0 [secondary effluent]
perc <20 min/inch
Loamy Sand: 0.8 gpd / ft2 [primary effluent]; 1.5 [secondary effluent]
perc =/>20 min/inch
Sandy Loam: 0.6 gpd / ft2 [primary effluent]; 1.0 [secondary effluent]
perc = 20-40 min/inch
Sandy Clay Loam: 0.4 gpd / ft2 [primary effluent]; 0.6 [secondary effluent]
perc = 40-60 min/inch
Perc Rates [if required]
30 min/inch, maximum, except for high shrink/swell soils
45 min/inch in high shrink/swell soils
BASAL AREA [Natural Ground Surface] Loading [Infiltration] Rates for Controlled Fill with LPP Pipe – Table 12 : BASAL AREA [Natural Ground Surface] Loading [Infiltration] Rates for Controlled Fill with LPP Pipe – Table 12 Group 1 Soils
Perc rates: 5-20 min/inch
Group 2 Soils
Perc rates: 21-40 min/inch
Group 3 Soils
Perc rates: 41-60 min/inch
Group 4 Soils – 2 divisions
Perc rates: 61-90 min/inch
Perc rates: 91-120 min/inch
Group 5 Soils – 2 divisions
Perc rates: 121-180 min/inch
Perc rates: >180 min/inch Group 1 Primary loading rates
1.0 - 0.8 gpd / ft2
Group 1 Secondary loading rates
2.0 - 1.6 gpd / ft2
Group 2 Primary loading rates
0.8 – 0.6 gpd / ft2
Group 2 Secondary loading rates
1.6 – 1.2 gpd / ft2
Group 3 Primary loading rates
0.6 – 0.4 gpd / ft2
Group 3 Secondary loading rates
1.2 – 0.8 gpd / ft2
Group 4 Primary loading rates
0.4 – 0.2 gpd / ft2
0.2 – 0.1 gpd / ft2
Group 4 Secondary loading rates
0.6 – 0.3 gpd / ft2
0.3 – 0.15 gpd / ft2
Group 5 Primary loading rates
0.075 gpd / ft2
0.050 gpd / ft2
Group 5 Secondary loading rates
0.125 – 0.1 gpd / ft2
0.075 gpd / ft2
DESIGN EXERCISE #2 3 bdrm. dwelling; flat lot; ASHES @12”; perc @ 12” = 120 min / inch Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; ES = End Slope; SS = Side Slope : DESIGN EXERCISE #2 3 bdrm. dwelling; flat lot; ASHES @12”; perc @ 12” = 120 min / inch Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; ES = End Slope; SS = Side Slope CALCULATE HEIGHT OF FILL
B.O.T. + 9” [pipe/gravel] + 12”cover
B.O.T [ Table 15 ]
CALCULATE SIDE & END SLOPES
3:1 Slope
CALCULATE DISTRIBUTION AREA [DA]
W = LLR 3.0 divided by FMLR [sand] 1.0
L = FR divided by LLR
Minimum DA (W): 420-3-1-.67(1) (b) 6 (ii) (IV)
DETERMINE EDF AMOUNT
AA (L) minus 1’ at each end
1 line for every 3’ of DA(W)
CALCULATE ABSORPTION AREA [AA]
[DA (L) + setbacks] x [DA (W) + setbacks]
420-3-1-.67(1)(b)7
DETERMINE BASAL AREA
Loading Rate Method
FR divided by BALR [Table 12]
Geometry Method
[ AA (L) +(2x ES] x [AA(W) + (2xSS) ]
LARGER OF THE TWO APPLIES
HEIGHT = 27” above NGS
[BOT] 6” + 9” + 12” = 27” above ngs
SIDE & END SLOPES =
27” x 3 = 81” / 12 = 6.75’
DA = 450 ft2 [ 3’ x 150’ ]
W = 3 / 1.0 = 3’
L = 450 / 3 = 150’
EDF = 148’ [ 1 line ]
150’ – 2’
AA = 1078 ft2
154 x 7
BA = 4500 ft2 [Appr 180’ X 25’]
SLOPES: Ends = 1:5.8 Sides = 1:4
Loading Rate Method = 4500 ft2
450 / .1 = 4500 ft2
Geometry Method = 3434 ft2
[154 + 13.5’] X [7’ + 13.5’] =
167.5’ x 20.5’ = 3433.75 ft2
DESIGN EXERCISE #2a 3 bdrm. dwelling; flat lot; ASHES @ 12”; perc @ 12” = 120 min / inch; Pre-treatment of effluent to Secondary Standards Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; ES = End Slope; SS = Side Slope : DESIGN EXERCISE #2a 3 bdrm. dwelling; flat lot; ASHES @ 12”; perc @ 12” = 120 min / inch; Pre-treatment of effluent to Secondary Standards Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; ES = End Slope; SS = Side Slope CALCULATE HEIGHT OF FILL
B.O.T. + 9” [pipe/gravel] + 12”cover
B.O.T [ Tables 15,13 & .67(1) (d) ]
CALCULATE SIDE & END SLOPES
3:1 Slope
CALCULATE DISTRIBUTION AREA [DA]
W = LLR 3.0 divided by FMLR [sand] 2.0
Table 13
L = FR divided by LLR
Minimum DA (W): 420-3-1-.67(1) (b) 6 (ii) (IV)
DETERMINE EDF AMOUNT
AA (L) minus 1’ at each end
1 line for every 3’ of DA(W)
CALCULATE ABSORPTION AREA [AA]
[DA (L) + setbacks] x [DA (W) + setbacks]
420-3-1-.67(1)(b)7
DETERMINE BASAL AREA
Loading Rate Method
FR divided by BALR [Table 12]
Geometry Method
[ AA (L) +(2x ES] x [AA(W) + (2xSS) ]
LARGER OF THE TWO APPLIES
HEIGHT = 27” above NGS
[BOT] 6” + 9” + 12” = 27” above ngs
SIDE & END SLOPES =
27” x 3 = 81” / 12 = 6.75’
DA = 450 ft2 [ 3’ x 150’ ]
W = 3 / 2.0 = 1.5’ [3’minimum]
L = 450 / 3 = 150’
EDF = 148’ [ 1 line ]
150’ – 2’
AA = 1078 ft2
154 x 7
BA = 3434 ft2 [Appr 167.5’ X 20.5’]
SLOPES: Ends = 3:1 Sides = 3:1
Loading Rate Method = 3000 ft2
450 / .15 = 3000 ft2
Geometry Method = 3434 ft2
[154 + 13.5’] X [7’ + 13.5’] =
167.5’ x 20.5’ = 3433.75 ft2
Fill Material and Construction of Bed Five Cs of Controlled Fill : Fill Material and Construction of Bed Five Cs of Controlled Fill Consistency of Fill
Uniform; free of trash and debris; consist with respect to texture and compaction
Compatibility of Fill
Compatible (if possible) with in-situ soil
Compaction of Fill
Stabilized; approximating “in-situ” condition
Construction of Fill Bed
Natural ground surface preparation
scarification, removal of vegetative cover, trees cut flat with ground surface
Placement of Fill
dry conditions (ground and fill)
in 6 – 12 inch lifts; working from upside, on placed fill
track type equipment
Certification of CF Bed and Installation
By design engineer
Fill material and bed construction inspected prior to EDF installation [.67(c)]
Tables 11 and 14; .67(b)10
SUMMARY OF DESIGN FACTORS CONTROLLED FILL USING SMALL DIAMETER LPP : SUMMARY OF DESIGN FACTORS CONTROLLED FILL USING SMALL DIAMETER LPP Small Diameter, Low Pressure Pipe [LPP]
Design Factors:
Fill Material Loading Rate [FMLR]
1.0, 0.8, 0.6, 0.4 gpd / ft2
sand, loamy sand, sandy loam, sandy clay loam
Linear Loading Rate [LLR]
3 to 10 gpd / L.F. of LPP
Use 3 gpd / linear foot of LPP in HShSw soils
Basal Area Loading Rate [BALR]
Ranges: 0.1 to 0.05 for primary effluent; 0.2 to 0.75 for secondary effluent
Use 0.05 gpd / ft2 for LPP discharging primary effluent into vertic clay
Slope Correction Factor
DESIGN EXERCISE #3 - LPP 3 bdrm. dwelling; 10% sloped lot; ASHES @12”; perc @ 12” = 50 min / inch Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; ES = End Slope; SS = Side Slope; NGS = Natural Ground Surface : DESIGN EXERCISE #3 - LPP 3 bdrm. dwelling; 10% sloped lot; ASHES @12”; perc @ 12” = 50 min / inch Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; ES = End Slope; SS = Side Slope; NGS = Natural Ground Surface CALCULATE DISTRIBUTION AREA [DA]
W = LLR 6 Divided by FMLR 1.0
L = FR divided by LLR
DETERMINE B.O.T. HEIGHTS
Upslope [Us BOT] height = Required Distance above ASHES
BOT [ Table 15 ]
Downslope [Ds BOT] height =
[Us BOT] + [slope% x DA(W)]
CALCULATE FILL HEIGHTS
Upslope= UsBOT + gravel/pipe + cover
Downslope= DsBOT + gravel/pipe + cover
DA = 450 ft2 [ 6’ x 75’ ]
W = 6 / 1.0 = 6’
L = 450 / 6 = 75’
UPSLOPE [Us BOT] HT. = 12” over NGS
24” above ASHES = 12” over NGS
12” below NGS + 24” = 12” over NGS
DOWNSLOPE [Ds BOT] HT. = 19” over NGS
12” + [.10 X 72”] = 12” + 7” = 19” over NGS
FILL HEIGHTS = 33” & 40”
U.s. Ht. = 12” + 9” + 12” = 33”
D.s. Ht. = 19” + 9” + 12” = 40”
DESIGN EXERCISE #3 – LPP page 2 3 bdrm. dwelling; 10% sloped lot; ASHES @12”; perc @ 12” = 50 min / inch Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; SCF = Slope Correction Factor; NGS = Natural Ground Surface : DESIGN EXERCISE #3 – LPP page 2 3 bdrm. dwelling; 10% sloped lot; ASHES @12”; perc @ 12” = 50 min / inch Abbreviations: LLR = Linear Loading Rate; FMLR = Fill Material Loading Rate; FR = Flow Rate; BALR = Basal Area Loading Rate; SCF = Slope Correction Factor; NGS = Natural Ground Surface CALCULATE END SLOPES LENGTH
Avg. of fill height x 3
3:1 ratio
CALCULATE SIDE SLOPES LENGTH
Upslope [Us]= 3 x [Us Ht] x SCF
Downslope [Ds] = 3 x [Ds Ht] x SCF
CALCULATE EDF AMOUNT
DA(L) minus 1’ at each end
1 line for every 3’ of DA(W)
CALCULATE ABSORPTION AREA [AA]
[DA (L) + setbacks] x [DA (W) + setbacks]
DETERMINE BASAL AREA [BA]
Loading Rate Method =
FR / BALR [Table 12]
Geometry Method =
[AA(L) + 2(ES)] x [AA(W) + (Us+DS)]
LARGER OF THE TWO APPLIES
END SLOPES LENGTH = 9.25’ per end
Fill avg. = [33” + 40”] / 2 = 73 / 2 = 37”
37” x 3 = 111” / 12 = 9.25’ per end
SIDE SLOPES LENGTH = 6’ and 14’
Us = [3 x 33”] x.77 = 99” x .77 = 76”; 6.33’
Ds = [3 x 40”] x1.44= 120” x 1.44 =173”; 14.4’
EDF = 146 LF; 2 x 73’ lines
L = 75’ – 2’ = 73’
# lines = 6’ / 3 = 2 lines
AA = 790 ft2 [79 x 10]
[75’ + 4’] x [ 6’ + 4’] = 79’ x 10’ = 790 ft2
BA = 2340 ft2
LRM = 450 / 0.5 = 900 ft2
GM = [79’ + (2x9.25’) x [10’ + 14’]
[79’ + 18.5’] x [10’ + 14’]
97.5’ x 24’ = 2340 ft2
CF Designs on Other Restrictive Sites : CF Designs on Other Restrictive Sites Minimum Above Ground Height of Trench Bottom
6”; trench bottoms not located at <6” [.67(1)(d)]
Pre-Treatment (Secondary Standards) Required:
Sites with <6 inches to ASHES [.67(1)(e)] (Average Seasonal High Extended Saturation) natural surface
Sites with <12 inches to Rock [.67(1)(f)]
Minimum OSS Requirements for CF Systems in Very High Shrink-Swell Soils : Minimum OSS Requirements for CF Systems in Very High Shrink-Swell Soils Minimum Size OSS Required
180 min/inch or greater [design rate for LDP]
BA loading rate of 0.75 gpd/ft2 of LPP
Regardless of perc test results
Can be approved at LHD level
If Another OSS Designed
Perc rate must be supported by PSC
rate is indicative of saturated condition
Design will be submitted to State thru LHD
Minimum OSS Sizing for CF in High and Very High Shrink-Swell Soils : Minimum OSS Sizing for CF in High and Very High Shrink-Swell Soils Design Factors to Note
Minimum Basal Area required
No “breaks” given for pipe types
“Breaks” given based on treatment only
Minimum Distribution Area required
Reduction can be given for type of pipe
Minimum Absorption Area required
Minimum EDF Amounts required
Reduction can be given for type of pipe
Concern: High and Very High Shrink-Swell Soils : Concern: High and Very High Shrink-Swell Soils Vertisols
High Clay Content [ 50 to 70 percent ]
Soil Periodically Opens [forms cracks], Closes
Shrinks When Soils Become Dry
Cracks = or >.2” form thru layer 10+” thick, and within 19+” of the mineral soil surface
Cracks remain open for a period of 60+ consecutive days between Jun 21st & Sept 21st
Expands When Soils Become Wet [saturated]
Cracks normally closed for period of 60+ consecutive days between Dec 21st & Mar 21st
Occurs in the Black Belt and Southern Coastal Plain
Other Soils
Vertic [Shrink-Swell] Characteristics
Occur Black Belt and the Upland Ridge and Valley Areas
Soil Series Examples : Soil Series Examples Vertisols: Uderts (Black Belt & Southern Coastal Plain)
Faunsdale: slightly poor drainage; slow permeability; occurs in B.Belt on concave side slopes, toeslopes; grayish brown, olive brown [ mottles: yellow, gray; black concretions ]
Hannon: moderately well drained; very slow permeability; occurs in B.Belt & S. Coastal Plain on side slopes; brown, olive brown, yellowish red [ mottles: red, gray; mica ]
Hollywood: moderately well drained; very slow permeability; occurs along footslopes and upland depressions of B.Belt; dark gray, olive brown, black; [ brown, gray & black mottles ]
Houston: moderately well drained; slow permeability; occurs in B.Belt; olive gray; [dark gray]
Maytag: well drained; slow permeability; occurs along slopes in B.Belt; olive brown, olive yellow; [ mottles: yellowish brown, olive yellow; soft calcium carbonate deposits ]
Oktibbeha: moderately well drained; very slow permeability; occurs in B.Belt on convex ridges & S. Coastal Plain along ridges; yellowish red, yellowish brown [ mottles: red, gray, brown; calcium carbonate deposits @ 3’ depth or greater]
Suggsville: well drained; very slow permeability; occurs along convex ridges and side slopes of B.Belt and S. Coastal Plain; brown, red, reddish gray, yellowish red; [ yellowish red, black concretions]
Vaiden: poorly drained; very slow permeability; occurs along upper slopes and stream terraces in B.Belt & S. coastal Plain; grayish and yellowish brown, olive brown [ mottles: brown, gray, brownish gray, red; black concretions; calcium carbonate deposits 4’ to 5’ ]
Watsonia: well drained; very slow permeability; occurs along convex ridgetops and side slopes of B.Belt; yellowish & olive brown, yellowish red, gray [mottles: yellowish red/brown; chalk @ 2’ or <]
Wilcox: slightly poor drainage; very slow permeability; occurs along uplands of S. Coastal Plain; dark brown, yellowish brown, yellowish red, red, brownish gray [brown, red, yellow & gray mottles]
Soil Series Examples : Soil Series Examples Vertisols: Aquerts (Black Belt and Southern Coastal Plain)
Consul: poorly drained; very slow permeability; occurs in uplands of B.Belt and S. Coastal Plain; grayish brown and brownish gray; [mottles of gray, yellowish brown and olive brown; black concretions around 4’]
Sucarnoochee: slightly poor drainage; very slow permeability; flood plain area of B.Belt; gray, dark gray and brownish gray; [mottles: brown and yellowish brown; black concretions @ 3’ ]
Eutaw: poorly drained; very slow permeability; occurs B.Belt and S. Coastal Plain, mainly in flat/level areas; dark gray, gray; [ yellowish brown, brownish yellow mottles ]
Other Soils: Vertic (Shrink-Swell Tendencies; B. Belt & Upland Ridge/Valleys)
Chisca: well drained; very slow permeability; occurs along the Upland Ridge and Valley areas, along hillsides; gray, yellowish brown, yellowish red, red [heavily mottled reds, grays and browns; shale increasing at 40” ]
Colbert: moderately well drained; very slow permeability; occurs along Upland Ridges and Valleys, hillsides; mostly brown; [ gray, yellowish brown, yellowish red ]
Iredell: moderately well drained; slow permeability; occurs along Piedmont Uplands; brown, grayish brown, olive; [black brown, grayish brown and greenish gray mottles with black concretions]
Leeper: slightly poor drainage; very slow permeability; occurs along flood plains and streams of B.Belt; brown and grayish brown; [gray, black and yellowish brown mottles; brown and black concretions ]
Tuscumbia: poorly drained; very slow permeability; along flood plains and terraces of B.Belt; gray; [brown and yellowish brown mottles; black concretions ]
DESIGN EXERCISE #4 3 bdrm. dwelling; flat lot located in a Vertisol soil; ASHES @10”; reported perc @ 12” = 90 min / inch : DESIGN EXERCISE #4 3 bdrm. dwelling; flat lot located in a Vertisol soil; ASHES @10”; reported perc @ 12” = 90 min / inch CALCULATE HEIGHT OF FILL
B.O.T. + 12” [pipe/gravel] + 12?”cover
B.O.T [ Table 15 ]
CALCULATE EDF AMOUNT
Table 3a
DETERMINE EDF LAYOUT
Rectangular
DETERMINE DA
DETERMINE AA
5’ setback on all sides
DETERMINE SIDE/END SLOPES
3:1 maximum slope
DETERMINE BASAL AREA
L = AA(L) + ES
W = AA(W) + SS
HEIGHT = 30” above NGS
[BOT] 8” + 12” + 12” = 32” above ngs
MINIMUM EDF = 1010 LF of 3’ trench
Basis: 180 min/in per =1010 ft2 / bedroom
DESIGN LAYOUT AMT. : 1010 LF
9 x 98’ lines + ends [ 2 x 64’]
882’ + 128’ = 1010 LF
DA = 101’ x 67’ = 6767 ft2
Includes 1.5’ on each end
AA = 111’ x 77’ = 8547 ft2
[101’+10’] x [67’ + 10’]
SIDE & END SLOPES = 8’
3 x 32” = 96“ /12 = 8’ per side/end
BA = 11,811 ft2 [127’ x 93’]
[111’+16”] x [77’ + 16’]
System Comparisons – 3 bdrm dwelling; flat lot; ASHES @ 12”; perc = 120 min/inch; primary treatment : System Comparisons – 3 bdrm dwelling; flat lot; ASHES @ 12”; perc = 120 min/inch; primary treatment
LOT MODIFICATIONS 420-3-1-.67(2) : LOT MODIFICATIONS 420-3-1-.67(2) Flow Charts
Non-wetland, Non-hydric, No ASHES <6”
Wetland, Hydric Soils, ASHES <6”
Cuts within 25’ of EDF (c)
Cuts with fill below NGS (d)
Cuts with fill above new GS (e)
Bench Cuts (f)
Fill on Non-Wet Sites OR Fill on Wetland, Hydric , Wet Sites : Fill on Non-Wet Sites OR Fill on Wetland, Hydric , Wet Sites Amount of time fill in place
Corp Approval [if applicable]
Monitored weekly thru 1 wet season
Site evaluated by PSC
If fill in place <3 yrs on non-hydric site
<5 years on hydric, wetland site or
A site with <6” to ASHES
Cuts Near EDF : Cuts Near EDF Depth of Cut
Proximity to EDF
Discretionary Actions for LHD
Geologist Report
Soils Classifier Report
Cut With Fill Below NGS : Cut With Fill Below NGS Use Conventional OSS if possible
No High Shrink/Swell Soils
Underlyiing Soil Characteristics
Soil Thickness Requirements & Depth to ASHES in Soil Layer
Certain Provision Included in Design
Cut With Fill Above New GS : Cut With Fill Above New GS No High Shrink/Swell Soils
LHD Options
Geologist Report
PSC High Intensity Map
Bench Cuts : Bench Cuts Type of Rock
Hard Rock? Prohibited
Other Rock? Design Stipulations
Required Reports
Geologist
PSC