HomeMy WebLinkAbout1991 - Septic System approval 11
Q Al � _" CITY OF ORONO
go ;ti, �.,
,� ✓� �. � SEPTIC SYSTEiVi APPROVAL
(----
0 , ,
^� . v 44C of ORONO
l� -.1`. 1". y Municipal Offices
l,, (. r1 d 2r it ° 0,...•0 d Past Office Box 66
V. Crystal Bay,Minnesota 55323.0066
`9kESBO
- LOCATION: 315 Woodhill Rd.
OWNER: John Prudden
GENERAL CONTRACTOR: SEPTIC CONTRACTOR:
SITE EVALUATOR: Percor, Inc. REPORT DATE: September 3, 1991
The City of Orono has Approved your on-site system design as of .
(approved-disapproved) (date) ,
with the following comments: � 4---- �'
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PA i
I.
THIS IS NOT A PERMIT. This is a design approval form which must accompany the site plan. A permit must
be issued to a licensed septic contractor prior to installation. A list of currently licensed septic contractors is
enclosed.
NOTICE TO INSTALLERS: Any changes to the approved plans and specs must have prior approval of the
Inspector (473-7357). Call for inspections 24 hours in advance.
ALL DRAINFIELD AREAS MUST BE FENCED OFF prior to building site excavation and fencing must remain
in place until final site grading. Approval to pour footings will not be granted until the Inspections Department
has verified that primary and alternate sites are adequately protected.
NO VEHICULAR TRAFFIC OF ANY KIND (cars, trucks, earth moving equipment, etc.) is allowed within 20'
of tested drainfield sites either before or after system construction. Compaction of these areas could render them
unusable prohibiting the timely completion and or limiting the long term use of the property.
A site copy will be available at the City Offices for the septic contractor.
CITY OF ORONO
/.
?
By 4/ /
Stephen W,• an, On-site Systems Manager
TELEPHONE-473-7357•FAX-473-0510
t I
SYSTEM DESIGN •
FOR JOHN PRUDDEN
315 WOODHILL ROAD
Enclosed are results of soil borings and percolation tests
taken on the Prudden property and system design material for the
pressure mound system needed. The flatter area tested by the
guest house looks to have enough room to treat 5 bedrooms or
750 gallons of wastewater per day, while hopefully saving the 30"
oak tree. An additional 12 . 5 feet of length could be added if
the oak tree were removed, thus allowing for 6 bedrooms or 900
gallons per day.
Two additional soil borings ( 3 & 4 ) were taken in a flat
open area to the south-southeast of the main', house and soils
encountered there indicated this would be a very good' area for
another future mound system.
In addition to the system design information enclosed, two
septic tanks of at least 1250 gallons and a pumping tank of 1000
gallons would be needed. All construction and materials ' must ad-
here to the provisions of the City of Orono, and drainage should
be diverted from the mound area.
If any other information is needed, please, .contact me . -- •
-
•
Sincerely,
PERCOR,
INC.
Mark S . Gronherg
.
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CITY or ORONG
ellILDING '; - - , 1 PL RENfle: ,,
4•45;PECTOR
. .. . _
DATE
PERMIT NO. ._
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APPRM LD AS SLIFM;TTED
APPROVED 'I1'H r '''. .:Lc.7 iors:.is AS NOTED
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NO APPRO‘,ED -- ' "'t-( -;:::CT & PESUBMiT -----ir .. ,PAI p 001 I.1(.0
44-ese comp .7,,, a F' :', , t.,-' I .' 'nation. All work ,-.hall he dor.6 /4r ,1 s
In I.11. ,'Imoci ::- ' bolilina & zoning corie v•
Vilr•sint•r•ts :11,..,0.-c, !err, not sPtcrficalli no!'f'd n trus ,e 0 N'''4 (?,.$) : Loce7
KEEP TH:S 1-',_.,\N SET ,..)i'•i SHE AI ALL TME..V .. •-
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/ S 6 E-19
MOUND DESIGN PROCEDURE
(For Flows up to 1200 gpd)
•
A. Sewage Flow Rate F. Pre'ssu`re Distribution System
See D-7 or I-3, 4, or 5, or use
metered value; Flow Rate = 1. Select number of perforated '
75a gpd laterals
2. Select perforation spacing
B. Septic Tank Liquid Volume L. 3 ft
(see C-3 or C-5) /23-0 gallons
I COp „ 3. Select perforated lateral
C. Soil Characteristics length; Note if manifold is
at end of rock layer, lateral
1. Depth to restricting layer leng hi .rock layer length
such as seasonally saturated less half a- perforation
soil, bedrock, coarse soil, spacing. .If manifold is in
etc. ; 7 ff inches center of rock layer, lateral
2. Depth of percolation tests; length is one-i�alf rock layer
/5 inches length less half a perforation •
spacing. Perforated lateral.
3. Number of percolation test length = 29. 7 ft.
holes; ,3 holes
4. Divide lateral length by perfor-
4. Ave. percolation rate; ation spacing to get number of
53- S mpi perforations per lateral
5. Landslope = / % 91,2 feet = 3 feet = /0 perfs
Note: last perforation must be
D. Rock Layer Dimensions ' in end cap, (see page E-14)
1. Multiply gpd by 0.83 to 5. Multiply perforations per
lateral.. by number of laterals
obtain required area of
rock layer; to get total number• of
. 750 gpd x 0.83 =(21.S sq ft perforations;
/0 perfs/lat x lats = (0
2. Select width of rock layer
(10 feet or less) _ /0 feet 6. Determine required flow rate
by multiplying number of
3. Length of rock layer = Area perforations by flow per
Widtha2,5sq ft /p fterforation
P (see page E-17)
0. 3 ft GO..p .r.f.s. •x0.7ygpm/perf = 5eV.Ygpm
•
E. Rock Volume 7. Select minimum required lateral
diameter from table on Page .E-17;
1. Multiply rock area by rock depth enter table with perforation
to get cubic feet of rock; spacing, perforation diameter,
(22.5 sq ft xO. 75ft = W7 cu ft and number of perforations per
2. Divide cu ft by 27 cu ft/cu yd lateral. Select minimum
• diameter for perforated lateral
t- get cubic yards; /13 =
3. .Multiply cubic yards by 1.4 to ///,,, inches uta. ��
Z
get weight of rock in tons; G. Basal Width
/7.3 cu yds x 1.4 7 .24/.. 2 tons 1. Percolation rate in top 12
inches of soil is SY $ mpi •
•
2. Select allowable soil loading
rate from table on page E-16;
• C�. VSgpd/ft2
/ ,�DiVit.-1 Aft./di,Ei✓
.
/ .•J BR E-20
MOUND DESIGN PROCEDURE (Continued) .
(For Flows up to 1200 gpd) ._. . . - ... •
G.3. Calculate basal width ratio H.2.f. Multiply dike multiplier by
by dividing rock layer 2 downslope mound height to get
loading rate of 1. 20 gpd/ft downslope dike width;
by allowable soil loading y 76 x..3, 9 = /2, 6 f t
rate;
1. 20 gpd/f t2 -0,`1$gpd/f t2 =2. 67 g. Compare the values of step H. 1
Check this value on page E-16. and step 11. 2•f. Select the
greater of the two values as
4. Multiply basal width ratio by the downslope dike width;
rock layer width to get ler- 6 feet
required basal width;
2, 67 x /G ft Z6, 7ft h. Calculate upslope dike width 3:
using upslope' mound height
H. Downslope Dike Widthand upslope diko_,multiplier
from page E-18•
1 . If landslope is 3% or more, Z. 6.' x 3.,� = ' 9, Y_f t
i. Total mound width is the sum
subtract rock layer width
from basal width to obtain of upslope dike width plus rock
minimum downslope dike toe width layer width" plus` �3ownslope dike
26. 7 ft - /p ft =./6"..-7ft width;
Y ft +" /o ft -F/l 6ft =.3p Oft nii:1
2. Calculate mound height at edge 3. If landslope is 2.9 percent or
of rock layer on downslope side; less, basal width includes both ' •
a . Determine depth of clean sand
4-114‘-6: 1"/6" ' fill at upslope edge of rock the upslope and downslope dike
'4l.F, s6'- s layer: ,/ 5 feet widths.
"771...147
b. Multiply rock layer width by a. Calculate downslope dike width
landslope to determine drop using steps }1.2.a . through
in elevation; 11.2.f; feet
/0x y % - 100 = 0. 7f t b. Calculate upslope dike width
c. Add drop in elevation to depth using upslope mound height and •
dike multiplier from Page E-18;
of clean sand at upslope edge
of rock layer to get depth of x ft = ft
clean sand at downslope edge , c. Add downslope—dike width. to
•
of rock layer. upslope dike width to rock
0, y f t + /. 5 f t = I. 9 f t layer width to get total mound
d. Add depth of clean sand at down- width;
slope edge to depth of rock ft + . ft + ft = ft
layer to depth of soil backfill --- ---
to get mound height at downslope d. Compare total mound width to
required basal widthfrom step
edge of rock layer;
/ G,..4 .9 f t +0.75 f t +425'f t =.3 9 f t If total mound width is
f
greater than' required basal
e. Enter table on page E-18 with width, use calculated dike
landslope and downsldpe dike ' widths. If required basal
ratio. Select dike multiplier width is greater than total
of y 7.6 • y:/ rea,,e mound width, increase downslope
dike width.
• 5 e.e
•
F-15
PUMP SELECTION PROCEDURE
A. Determine• pump capacity:
J . Minimum suggested is 600 gallons per hour (10 gpm) -
to stay ahead of 'water use rate
2. Maximum suggested for delivery to a drop box of a home
system is. 2700 gallons per hour (45 gpm) to prevent
buildup of pressure in drop box
3. Use value from design of pressure distribution system
SELECTED PUMP CAPACITY yy , y •
gpm
B. Determine head requirements:
1 . Elevation difference between pump and point of discharge y '_'� feet
2. If pumping to a pressure distribution system, add 5 feet
for pressure required at manifold
5 feet ..
3. Friction loss .., ----
a. Enter friction loss table, with gpm and pipe diameter.
Read friction loss in feet per 100 feet from page F-18.
F. L. _. 2. 64/ ft/100 ft
' b. Determine total pipe length from pump to discharge
point. Add 25 percent to pipe length for fitting
loss, or use a fitting loss chart. Equivalent pipe
length = 1.. 25 times pipe length = 1.25 x SO = 4%Z. S *feet
c. Calculate total friction loss by multiplying
friction loss in ft/:L00 It by equivalent pine
length . Z . cv
Total friction loss = D x (2. S = /, (5 feet
4. Total head required is the sum of elevation difference,
special head• requirements, and total friction loss. •
+ s + /. (S
TOTAL HEAD 110 6-5 -feet
•
C. Pump selection
•
1 . A pump must be selected to deliver at least SAO, 3 gpm
with at least /0, 65 feet of total head.
D. To maximize pump life select sump size for 4 to 5 pump ,
operations per day.
•
F. Calculate drainback •
1 . Determine total pipe length, So feet .-
2. Determine liquid volume of pipe, /7, '/j gallons per
100 feet. (See 'page E-18)
3. Multiply length by volume: Drainback quantity = •
5d feet x /7.'f3, gallons/100- ft = 7. 7 gallons
4. Suggested drainback quantity is 10 percent ofpumped quantity.
A•larger drainback percentage will decrease pump station
efficiency. slightly but pumping energy costs are usually a
• relatively small part Of the total household• -energy-costs.•
•
B-39
PERCOLATION TEST DATA SHEET
Test hole location JO)) N P " iiDj9ij Hole number
Date test hole was prepared 7- Z - , Depth of hole bottom, /,S'- inches.
Diameter of hole, inches. •
Soil data from test hole:
Depth, inches Soiitexture'
O -/Z 8tA A C0.1"
/2.-/5 QitGli-.v Cfr 4a,l,
•
Method of scratching sidewall ,c( 4' b"C /! Ft . .
Depth of pea-sized gravel in bottom of hole, 2 inches.
Date and hour of initial water filling '7 --24:/ __ Cy) L
Depth of initial water filling, $ inches above hole bottom.
Method used tomaintainat least 12 inches of water depth in hole for at least
^
4 hours e e !- 1`L L
Percolation test readings made by () OA/ 6-h'n ti 6 L:R G.. on
7-30-- qI starting at /b, -a.mm. . Maximum water depth above hole bottom
(date) p.m.
during test, i/Q `a inches.
J
Time Percolation
Time Interval, Measurement, Drop in water rate, Remarks
Minutes inches level, inches minutes per
inch
• L am/ 1
•
O II • •
•
O/1 . 1
It I 1l1111=111111111111 o
1111111111.1111111111111111111
Percolation rate = 4 0minutes per inch.
B-39
PERCOLATION TEST DATA SHEET
Test hole location U O 4 n) PL) DOEA1 Hole number
Date test hole was prepared 7— 27-9) , Depth of hole bottom, ,i,�' inches.
Diameter of hole, 4 inches.
Soil data from test hole:
Depth, inches Soil texture
- 8 • Dt4rk ea„c>i
(-/5 B.(o w,✓ C c I7 [o.r n�
•
Method of scratching sidewall ` g;',4T4. 4 ER
Depth of pea-sized gravel in bottom of hole,
inches.
Date and hour of initial water filling 7-27— ? ) t1/ .�' P frI
Depth of initial water filling, /j-- inches above hole bottom.
Method used to maintain at least 12 inches of water depth in hole for at least
4 hours ti7
Percolation test readings made by �� 6-420.444--R6_ on
7 - 3!)— I / starting at /61. S.�' a'nl . Maximum water depth above hole bottom
(date) � �
during test, /1 inches.
Time Percolation
Time Interval, Measurement, Drop in water rate, Remarks
Minutes inches level, inches minutes per
inch
ysf 1/, L
9,30 e. GL jr;L
Ia,,5SSAG
//, 2 9 .3 a 1j1N 4 ler / 'rb
/!, i , ii ;'s'Y
sf, 124' _
Percolation rate = 53,. 3 minutes per. inch.
B-39
• PERCOLATION TEST DATA SHEET
Test hole location .7,0) N �.) D/1::,4J Hole number 3
`.--- Date test hole was prepared 7— p9 -- ' j , Depth of hole bottom, /S- inches.
Diameter of hole, ' 4 inches.
Soil data from test hole:
Depth, inches Soil texture
0 -i? /f z ire e o4Th . .
1-15 n',.fGwx., c r L O A/h
Method of scratching sidewall ( ,i47e, lick
Depth of pea-sized gravel in bottom of hole,. ,2 inches.
Date and hour of initial water filling .
Depth of initial water filling, d,• inches above hole bottom.
Method used to maintain at least 12 inches of water depth' idliole for at least
4 hours a G r 1 L. L
Percolation test readings made by Poi j -ipp21 biz n'fr on
7—340 '1/ starting at // 0a.m. Maximum water depth above hole bottom
(date) p.m.
during test, / b 1/f, inches.
Time ' Percolation
Time Interval, Measurement, Drop in water rate, Remarks
Minutes inches level, inches minutes per
inch
• v
•
ail., INIIIM11111111111111111111.10111111•11
•
•
•
Percolation rate L/k minutes per inch.
Lops of Soil Borings
•
B-18•
Location .or Project .761AN fet.41)1P
•
•
Borings made by 115WX,51- )90p (c/aPA)44:rie6. Date
• Classification System: AASHO ; USDA-SCS Unified ; other
.'Auger used (check two) : Hand or Power ; Flight , or Bucket X : other
Depth, • Boring number ' Dcpth, Boring number
in • in
Surface elevation 77. 3 feet Sueft:Ce *apvation 98. 2
feet
•
OftAek codni (A-,40
CLAY ( Al (P/4 )
• • BLACK COAivl
— ezAcie ea,oa-k
cRAY ifACIG41 eZ4)-- (pAttn
9 —•
Ctir zdAm
3 — 844-1 el..4'Y Z444-t
3•
•
4 — 4 --
• •
, .
5 — 5 ---
6 — 6 ---
. .
• . .
• , 7 —
• •
•
•
. 8 —
8 —
_:_LEnd of boring at 0 feet. End of- b6ring at feet.
Standing water table: Standing water table :
. .
•P9- .esent at feet of depth, Present at — feet 'of. depth,
hours after boring. hours after boring.
Not present in boring hole X Not present in boring hole X
--------'
s• •
Mottled soil : Mottled soil:
Observed at /. 5 feet of depth. • Observed at ' /, of depth.
Not present in boring hole Not present in boring hole
Observationsand comments:
Obsurvations and comments:,
•
•
•
• Logs of Soil Borings B-lB
' � 1
Location .or Pro f ect 1)/N_420...EA/
--- ---•
- -- --- -----
• Borings made by Al,L42/ &e a A/A ,Z••• Date — L- -
• Classification System: AASHO ; USDA-SCS '_;''Unified ; other _
Auger used (check two) : Hand /, or Power ; Flight , or Bucket ✓1 : other
i
Depth, • Boring number '. 3 _ Depth, Boring number ___ y
in •Surface elevation , in --
feet feet Surface elevation _.
Bow« ( An1 •
—
9L.4Ck`'ZoA�
l •
— i
—.
A 61 Bit GG✓,v e040.1
/P 6D ex6e44-, CL.r y C✓i!M
3 — 3 --
•
4 -- 4 — •--..
•
•
•
• 5 —
6 — 6•
•
•
•
• . 7 -- 7 —
•
• 8 — 8 —
•
•
End of boring at 440 feet. End of boring% .0A1.- --4! O feet.
Standing water table : Standing. water table:
l4esent at feet of depth, Present at feet of depth ,
hours after boring. hours after borins<.
trot present in boring hole Not present in borin hole
Mottled soil : Mottled soil:
. Observed at 0 feet of depth. observed ,at.. 3•. feet of depth. .
Not present in boring hole _ Not present in boring hole _T I
Observations and comments; Observations,and cow=t.s: