HomeMy WebLinkAbout1987 Septic system design and test reportSYSTEM DESIGN
FOR EIOEN CONSTRUCTION
OF LOT 9, BLOCK I, ABINGDON GLEN
ORONO, MINNESOTA
11-5-87
1. Percolation Rate, Type of System.
30.8 minutes per inch. Shallow Trench System with an interceptor draintile.
2. Proposed Flow Rate.
4 bedrooms @ 150 G.P.D. = 600 G.P.D.
3. Soil Treatment Area Needed.
Use 2.20 factor x 600 G.P.D. = 1320 Sq. Ft.
4. Size and Number of Trenches.
4 trenches 3 feet wide and 110 feet long = 1320 Sq. Ft. These trenches would
be spaced 7.5 feet apart center to center and be 0.5 ta 1.0 feet deep in the
natural soil. If 1.0 feet deep, the interceptor draintile would need to be
at least 3 feet lower than the bottom of the trench.
5. Drainfield Rock Needed.
44.4 cubic yards of rock is needed to have 6 inches under and 2 inches over
a 4 inch distribution pipe.
6. Septic Tanks.
Two tanks of at least 1000 gallons are needed. Depending on the final hous^
elevation, it may be necessary to have a third pumping tank of at least
gallons.
7. All construction and materials must adhere to the provisions of the City of
Orono. All grading and construction traffic must be kept from both the pri
mary and the alternate drainfield sites. The interceptor draintile must be
at least 10 feet upslope from the highest trench. If any other information
is needed, please contact me.
Sincerely,
PERCOR, INC.
Mark S. Gronberg, ^
PCA certified
ESS
WILLOW PROPERTIES
LOT 2, BLOCK 2
Percolation Results
Hole No.Material Percolation Rate
P-1 Brown Loam 30.0 Min./Inch
P-2 Brown Loam 21^.0
P-3 .Brown Loam 30.0 ”
P-4 Brown Clay Loam O•oP-5 Brown Loam 34.3
P-6 Brown Loam 26.7 ”
The average percolation i*ate is 30*^ minutes per inch.
Soil Borings
S.B. tf 1
Depth(ft.)
0.0-1.0
1.0-1.5
1.5-6.0
Material
Black Loaifi
Dk. Brown Clay Loam
Brown Loam
Mottled soil at 3.5 feet and water
'table at 3.6 feet after 21). hours.
S.B. # 2
Depth(ft.)
0.0-0.8
O.e-1.5
1.5-6.0
Material
Black Loam
Dk. Brown Clay Loam
Brown Loam
Mottled soil at 3.5 feet and water
table at 3.7 feet after 21). hours.
S.B. // 3
Depth(ft.)
0.0-0.8
0.8-1.6
1.6-6.0
Material
Black Loom
Dk. Brown Clay Loam
Brown Loam
Mottled soil at 3.0 feet and water table at 3.2
feet after 24 hours.
V
X
DIVERSION FOR
SURFACE WATER
GRASS COVER
1 ----
6-| 12-
>
•AT LEAST 10-
^ —
ORAINFIELO
TRENCHES
^iaCZSJW"..REMOVE EXCESS -
SOIL WATER
3 ’
1 ___
ORIGINAL
GROUND
SURFACE
SOIL TREATMENT UNIT USING SHALLOW
TRENCHES AND INTERCEPTOR DRAIN
f
Ul
SEPTIC SYSTEM INFORMATION
STREET ADDRESS --- - - - - -
LOT 9 BTitrK / SUBDIVISION
MONTH AND YEAR TESTING DONE-- - - - -/?^3- - - - - - ---
ITEMS ALREADY COMPLETED.
NEED TO COMPLETE BEFORE ISSuXiNG BUILDING PERMIT;
BORINGS_ _ _ _ _ ___ _ _ _ _ _ _ _ _ _ _ ___ _ _ _ _
o
0
O
PERC TESTS
SYSTEM DESIGN
SITE PLAN
OTHER
DATE THIS SHEET PILED /- ^
SUBDIVISION FILE NO.
TO: Jeanne A. Mabusth, Zoning Administrator
FROM; Michael P. Gaffron, On Site Manager
DATE: June 15, 1983
SUBJECT: Proposed Subdivision for Willow Properties,
Gary Peterson - Soils and Site Investigation
Review
have reviewed the ten proposed lots and wish to make the
following comments:
Based on the Hennepin County Soil Survey, soils on
this property include Lester loams and clay loams,
Hayden loams, Hamel loeuns and LeSeur loams, as
well as a good deal of marsh. Tested sites are
located on the higher, better-drained soils. Some
areas of sandy soil were reported on the most
easterly lots. Based on the soils and water table
data submitted, shallow trench or standard trench
systems appear suitable for all lots. Following is
a summary of the soils data for each site:
Lot 1 Block 1 - Percolation Rate Average 22 MPI both
sites
- Primary site - slope 5% - mottling at 3.5' - water
table at 3.5' - modified shallow trench system*
Maximum Trench Depth 6" into original soil
- Alternate site - slope 8% - mottling at 4.0'
Water table at 4.9' - shallow trench system - maximum
trench depth 12" into original soil
Lot 2 Block 1 - Percolation Rate Average 18 MPI both sites
- Primary site - slope 7% - mottling at 4.2', 5.0' - water
table at 4.5', 5-5' - shallow trenches - Maximum Trench
Depth 14" into original soil.
- Alternate site - slope 8% - mottling at 3.3' - water
table at 3.3' - modified shallow trenches* - maximum
trench depth 4" into original soil
Lot 3 Block 1 - Percolation Rate Average 23 MPI both
sites
- Primary site - slope 10% - mottling at 4.0', 4.5' -
water table at 4.0', 5.5' - shallow trenches -
maximum trench depth 12" into original soil
- Alternate site - slope 8% - mottling at 3.5' - water
table at 3.6' - modified shallow trenches*- Maximum
Jeanne A. Mabusth
June 15, 1983
page 2
W
Trench Depth 6" into natural soil
Lot 4 Block 1 - Percolation Rate Average 19 MPI both
sites
- Primary site ~ slope 12% - mottling at 5.0*, 5.8*
water table at 7.7*, 7.2* - standard trenches - maximum
trench depth 24" into original soil
- Alternate site - slope 14% - mottling at 5.0* - water
table not encountered - standard trenches maximum trench
depth 24" into original soil
Lot 5 Block 1 - Percolation Rate Average 8 MPI ^primary
site) 28 MPI (alternate site)
- Primary site - slope 7% - sandy soils, mottling not en
countered, water table at 5.3', 6.0* - standard trenches
- maximum trench depth 28" into original soil
- Alternate site - slope 7% - mottling at 5.0* - water
table at 5.2* - standard trenches - maximum trench depth
24" into original soil
Lot 6 Block 1 - Percolation rate average 13 MPI (primary
site) 19 MPI (alternate site)
- Primary site - slope 9% - mottling not encountered - water
table at 7.5*, 7.8* - standard trenches
- Alternate site - slope 10-12% - mottling at 4.3*, water
table at 6.8* - shallow trenches - maximtim trench depth 16"
into original soil
Lot 1 Block 2 - Percolation Rate Average 26.3 MPI both sites
- Primary site - slope 8% - mottling at 5.5*, 5.9*, water
table at 5.6*, 5.9* - standard trenches - maximum trench
depth 30" into original soil
- Alternate site - slope 7% - mottling at 3.5*, water table
at 4.3* - modified shallow trenches* - maximum trench
depth 6" into original soil
/ Lot 2 Block 2 - Percolation rate Average 31 MPI both sites
/ - Primary site — slope 5% — mottling at 3.5* - water table
/ at 3.6*, 3.7* - modified shallow trenches*
I - Alternate site - slope 5% - mottling at 3.0* - water table
I at 3.2* - or Mound - maximum
I trench depth - at soil surface (see not<
I trenches)
(see note below re modified
Lot 3 Block 2 - Percolation Rate Average 10 MPI both sites
- Primary site - slope 8% - mottled at 4.5*, 5.0* - water
Jeanne A. Mabusth
June 15, 1983
page 3
table at 4.5', 5.3* - shallow trenches - maximum trench
depth 18” into original soil
- Alternate site - slope 6% - mottled at 3.8’, water
table at 3.8* - modified shallow trenches* - maximum
trench depth 10" into original soil
Lot 4 Block 2 Percolation Rate Average 14 MPI both sites
- Primary site - slope 7% - mottling at 4.4', 5.5* -
water table at 4.4*, 5.6* - shallow trenches - maximum
trench depth 17" into original soil
- Alternate site - slope 5% - mottling at 4.0* - water
table at 6.4* • shallow trenches > maximum trench depth 12*
into original soil.
•Modified Shallow Trenches - where water table or mottling
is bet%feen 3.0* and 4.0* below the surface, a standard
12" rock depth (6" under pipe, 2" over) must be used in
conjunction with an appropriate depth of fill material
to retain a 3.0* separation between the bottom of trenches
and the water table or mottling. Fill should consist of
material classified as loamy sand (USDA classification).
The original soil must be dryer than the plastic limit
before placing fill. The original surface roust be scarified
or disced to break up the surface vegetation mat. The
loamy sand fill must be placed over the entire area so that
no trench will be located less than 10 * from the edge of
the fill. The depth of fill required will depend on the
allowable depth of excavation into original soil based on
the water table or mottling.
I recommend that the subdivision be approved as proposed. The
developer should be warned to keep all traffic, fill excavation,
etc. away from the tested drainfield sites. In some cases
where road construction will be near the tested sites, extra
caution must be taken.
MPG:jl
sxn EVAUimoii kbpoiit
FOR vxxxou Momrxts
( OART PETERSOK )
OROKCf KXmSOTA
5-30.63
m
On Kaj U-30* 1963 six psreolstion holts wsro tsstsd on
«seh of 10 lets and 3 soil borlnfs token on eoeh lot ss well
in oeeordsnee with the provisions of Xndividusl Sewage Sys-
ten Trestnent Standards (VFC.U0) adopted in 1976 by the Finn*
esota Pollution Control Ageney* Xn addition* other soil bor*
ings were taken in lower areas to detemine the possibility
of obtaining more than 10 lots but water tables were found
to be very high and the soils were found to be very slowly
pemeable.
According to the soils maps and the information we
found in the field* the higher areas had very good soils for
drainfields while the lower areas and swales had extremely
poor soils for drainfields. Thus* we tended to stick to the
higher areas while still leaving room for ample building
sites. However* cnee houses are proposed to be constructed
it might be desired to shift some of the drainfield areas.
Then n w testing would be required and it would be advise-
able to keep ls high up 0:1 the kntb? as was previously tes
ted.
Each site tested '.c.Tuld be acceptable for either a stcn*
dard or shallow trench drainfield system and is noted on the
attached drawing. It also night be necessary to use inter*
ceptor drains to divert runoff water but this would be men-'
ticned in the system design for the Individual houses once
they ere ready for construction. If any additional informa
tion is needed* please contact me.
Sincerely*
PERCOR* IKC.
“^Mark S. Gronberg*
vxuoH rtomrxBs
^LCT 2, BtCCK
P«reol*tien Wfulf
Hole Be.Katerial Percolation Bate
P*1 Brown Loan 30.0 mn./Xnch
7-2 Brown Lean 24.0 •
P-3 Brown Loan 30.0 •
P-4 Brown Clay Loan .40.0 •
P-5 Brown Loan 34.3 •
P-6 Brown Loan 26.7 •
Th« av«rss« ptreolation rat« Is 30.6 nlnutss psr inch.
Sell Borings
S.g. * 1
asrthCft.^
0. e-i.o
1. c-1.5
1.5-6.0
Mottled soil
table itt 3*6
8.B. » 1
Decth(ft.^
0.0-0.6
0.6-1.6
1.6*6.0
Kfcter^s^
Blsek loan
Dk. Brown Clay Loan
Brown I|^ an
^ ^eet. and water
after 24 hours.
S.B. ^ 2
Depth! ft.)
0.0-0.6
o.e-1.5
1.5-6.C
feetaft
Meter|a^
Black Uaa
Dk. Brown Clay Lear.
Brown Loan
Mottled soil kt' l.g fe^ and water
table at 3*7 feet after 24 hours.
Material
Black Loan
Ok. Brown Clay Loan
Brown Loan
Mottled soil, at 3.0. feet and water table at 3.2
feet after 24 hours.