HomeMy WebLinkAbout03932f • GARFIELD COUNTY BUILDING AND SANITAflON DEPARTMENT
109 8th Street Suite 303
Glenwood Springs, Colorado 81601
Phone (303) 945-8212
INDIVIDUAL SEWAGE DISPOSAL PERMIT
PROPERTY
Permit N~ 3932
Assessor's Parcel No.
This does not constitute
a building or use permit.
Owner'• Nameb1c I/.... Q ~(1oe,r~esent AddressQl1SJ5 l-\wy (ot\--921..\-~Q\.}i;'one 4, 015" -I%'±
System Location 'da IV-& L Q_ 8'5 rJ :) {-ftµ j le f 0. 'f
Legal Description of Assessor's Parcel No. ________ _,,Q""'~/_,,2'---'2~-_,__/.L/...J/L---_,OO=~:Q_,,._C\-"CJ""'-----------
SYSTEM DESIGN
______ Septic Tank Capacity (gallon) ______ Other
_____ Percolation Rate (minutes/inch)
Required Absorption Area -See Attached
Special Setback Requirements:
Date _____________ Inspector ___________________________ _
FINAL SYSTEM INSPECTION AND APPROVAL (as installed)
Call for Inspection (24 hours notice) Before Covering Installation
System Installer ________________________________________ _
Septic Tank Capacity ______________________________________ _
Septic Tank Manufacturer or Trade Name--------------------------------
Septic Tank Access within 8" of surface --------------------------------
Absorption Area----------------------------------------
Absorption Area Type and/or Manufacturer or Trade Name --------------------------
Adequate compliance with County and State regulations/requirements _____________________ _
Other----------------------------~---------------
Date //_ 2 -D t{ Inspector ;t ~aeeJ £f'Jlt!(/JJ'. &/e-. ?£, ~ RETAIN WITH RECEIPT l:coA: AT CONSTRUCTION SITE •
•CONDITIONS:
1. All installation must comply with all requirements of the Colorado State Board of Health Individual Sewage Disposal Systems Chapter
25, Article 10 C.R.S. 1973, Revised 1984.
2. This permit is valid only for connection to structures which have fully complied with County zoning and building requirements. Con-
nection to or use with any dwelling or structures not approved by the Building and Zoning office shall automatically be a violation or a
requirement of the permit and cause for both legal action and revocation of the permit.
3. Any person who constructs, alters, or installs an individual sewage disposal system 1n a manner which involves a knowing and material
variation from the terms or specifications contained in the application of permit commits a Class I, Petty Offense ($500.00 fine -6
months in Jail or both).
Whtte. APPLICANT Yellow -DEPARTMENT
INDIVIDUAL SEWAGE DISPOSAL SYSTEM APPLICATION
OWNER Dick Casey Concrete Co
PHONE 970/625-1464 ADDRESS 27858 Rwy 6 & 24. Rifle. co 81650
CONTRACTOR'-----::'"1111<'---------~~~~~~~~~~
ADDRESS _______________ _ PHONE -----
PERMIT REQUEST FOR (x) NEW INSTALLATION ( ) ALTERATION ( ) REPAIR
Attach separate sheets or report showing entire area with respect to surrounding areas, topography of area, habitable
building, location of potable water wells, soil percolation test holes, soil profiles in test holes (See page 4).
LOCATION OF PROPOSED FACILITY:
Near what City ofTown~_R1_· f_l_e ____________ Size of Lot 9. 93 acres
Lega!DescriptionorAddress 28575 Hw.y 6 & 24, Rifle, co 81650
WASTES TYPE: ( ) DWELLING ( ) TRANSIENT USE
( iQ COMMERCIAL OR INDUSTRIAL ( ) NON-DOMESTIC WASTES
( ) OTHER-DESCRIBE _______________ _
BUILDING OR SERVICE TYPE: __ of_f_i_ce ____________________ _
Number of Bedrooms -----Dl'./-A.------~Number of Persons_~4 __ _
( ) Garbage Grinder ( ) Automatic Washer
SOURCEANDTYPEOFWATERSUPPLY: (x)WELL
If supplied by Community Water, give name of supplier:
( ) Dishwasher
( ) SPRING ( ) STREAM OR CREEK
DISTANCE TO NEAREST COMMUNITY SEWER SYSTEM: Approx 2 miles -~-----------
Was an effort made to connect to the Community System? --"N=o _____________ _
A site plan is required to be submitted that indicates the followini: MINIMUM distances:
Leach Field to Well: lOOfeet
Septic Tank to Well: 50 feet
Leach Field to Irrigation Ditches, Stream or Water Course: 50 feet
Septic System (septic tank & disposal field) to Property Lines: 10 feet
YOUR INDIVIDUAL SEWAGE DISPOSAL SYSTEM PERMIT WILL NOT BE ISSUED WITHOUT
ASITE PLAN.
GROUND CONDITIONS:
Depth to first Ground Water Table_~2_• ..-6~"---------------------
PercentGround Slope _____ _,,_ _____________________ _
TYPE OF INDIVIDUAL SEWAGE DISPOSAL SYSTEM PROPOSED:
( x) SEPTIC TANK ( ) AERATION PLANT ( ) VAULT
( ) VAULT PRIVY ( ) COMPOSTING TOILET ( ) RECYCLING, POTABLE USE
( ) PITPRIVY ( ) INCINERATION TOILET ( ) RECYCLING, OTHER USE
( ) CHEMICAL TOILET( ) OTHER-DESCRIBE
FINAL DISPOSAL BY:
( x) ABSORPTION TRENCH, BED OR PIT ( ) EV APOTRANSPIRA TION
( ) UNDERGROUND DISPERSAL ( ) SAND FILTER
( ) ABOVE GROUND DISPERSAL ( ) WASTEWATER POND
( ) OTHER-DESCRIBE
WILL EFFLUENT BE DISCHARGED DIRECTLY INTO WATERS OF THE STATE?_:N:..::.o __ _
PERCOLATION TEST RES UL TS: (To be completed by Registered Professional Engineer, if the Engineer does the
Percolation Test)
Minutes_~6=0 _ _,per inch in hole No. 1 Minutes __ 40.:::8..::.0 __ _,per inch in hole No. 3
Minutes 480 per inch in hole No. 2 Minutes er inch in hole No.
Name, address and telephone ofRPE who made soil absorption tests: Ronald .L !Ihle. P .E.
PO Box 1887, Silverthorne, CO 80498 970/468-1989
Name, address and telephone ofRPE responsible for design of the system: _ __,,s"'arn=e,,__ _____ _
Applicant acknowledges that the completeness of the application is conditional upon such further mandatory and
additional tests and reports as may be required by the local health departmentto be made and furnished by the applicant
or by the local health department for purposed of the evaluation of the application; and the issuance of the permit is
subject to such terms and conditions as deemed necessary to insure compliance with rules and regulations made,
information and reports submitted herewith and required to be submitted by the applicant are or will be represented to
be true and correct to the best of my knowledge and belief and are designed to be relied on by the local department of
health in evaluating the same for purposes of issuing the permit applied for herein. I further understand that any
falsification or misrepresentation may result in the denial of the application or revocation of any permit granted based
upon said application and in legal action for as provided by law.
Date ft. Od?-0 L. /
TO YOUR PROPERTY_!_,,! --='---=--7~---
HEPWORTH -PAWLAK GEOTECHNICAL
March 25, 2004
Casey Concrete
Attn: Rob Willits
P.O. Box 1815
Rifle, Colorado 81650
Hepworth-Pawlak CJentechn1cal, Inc.
P. 0. Drawer 1887
Stlverthorne, Cok1rado 80498
Phone 970-468-1989
Fax· 970-468-5891
email: hpgen4@hpl!e11tech.n1n1
Job No. 404 119
Subject: Percolation Testing and Individual Sewage Disposal System Design,
Proposed Office Building, Rifle Commercial Center, 28575 Highways 6 and
24, Garfield County, Colorado.
Dear Mr. Willits:
As requested, Hepworth-Pawlak Geotechnical, Inc. (H-P Geotech) has performed
percolation testing and designed an Individual Sewage Disposal System (ISDS) for the
proposed office building at the Rifle Commercial Center, located at 28575 Highways 6
and 24, Garfield County, Colorado. The study was conducted in accordance with our
agreement for engineering services to you dated January 21, 2004. The data obtained
and our recommendations based on the proposed construction and subsurface conditions
encountered are presented in this report.
Percolation Testing: Percolation tests were conducted on March 4, 2004 to evaluate
the percolation rate of the natural soils. One Profile Pit and three percolation test holes
were excavated at the locations shown on Figure 1. The test holes (nominal 10 inches
in diameter) were hand dug at the bottom of shallow backhoe pits and soaked a
minimum of 8 hours prior to testing. The soils exposed in the Profile Pit are shown on
the Log of Profile Pit, Figure 2. The subsoils encountered consist of approximately 1.5
feet of topsoil overlying a clayey, sandy to very sandy silt to the depth explored of
about 8.5 feet. No free water was encountered in the Profile Pit at the time of
excavation. Free water was observed at a depth of about 2.5 feet below ground surface
Glenwood Springs 970-945-7988 • Parker 303-841-7119 • Colorado Springs 719-633-5562
• ..
Casey Concrete
, March 25, 2004
Page2
during previous exploration at the site, A PVC pipe piez.ometer was installed in the
profile pit so that ground water levels can be monitored when irrigation begins in the
area, The soils exposed in the percolation test holes were similar to those exposed in
the Profile Pit The percolation tests were performed at depths of about 32 inches
below the adjacent ground surface, The percolation test results are presented on Figure
3, The percolation rates varied from about (J() to 480 minutes per inch (mpi),
Therefore, a percolation rate of 480 minutes per inch was used for sizing of the
mounded absorption area.
ISDS Analysis: Based on the low permeability of the subsoils and the shallow
groundwater previously encountered at the site, the area is suitable for an ISDS utilizing
a mounded absorption area for treatment and dispersal of effluent The mounded
absorption area consists of two equal siz.ed z.ones which will be alternately dosed via an
Orenco V 4402 automatic distributing valve. The two z.ones are located across gradient
from one another and the alternate dosing will provide a better hydraulic resting time
between effluent doses. The absorption area was siz.ed based on a percolation rate of
480 minutes per inch and an average daily flow rate of 18.2 gallons per employee. The
system is designed to accommodate five full time employees. It is our understanding
that the office building will be a converted modular residence with two full bathrooms.
The ISDS is not designed to accommodate additional flows from shower stalls and/or
bath tubs. We recommend cutting and capping the water supply plumbing to the
showers and tubs. Water is supplied to the existing garage and proposed office building
via a water well located west of the site on Lot 1. ISDS calculations are shown on
Figure 4. A site plan showing the proposed ISDS, existing garage, proposed office,
property Jines and the minimum horiz.ontal distances of these features relative to the
ISDS is shown on Figure l,
404 119
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Casey Concrete
, March 25, 2004
Page 3
Septic and Dosing Tanks: A concrete 750 gallon, two chamber, Valley Precast septic
tank, or equivalent, will be used for primary treatment of sewage from the residence.
Sewage will gravity feed to a single chamber, concrete, 500 gallon dosing tank. A high
head submersible effluent pump will be used to dose the two z.ones of the mound
absorption area. The submersible effluent pump should be installed inside a screen
vault within the dosing tank or an approved effluent filter should be installed on the
outlet of the second chamber of the septic tank. Approved risers should be installed on
septic tank and dosing tank access ports to allow easy access for maintenance. Septic
tank riser lids should be insulated to provide frost protection if installed at grade.
We have determined that a minimum of 2 feet of backfill soil needs to be placed above
the concrete septic tank and the dosing tank lids to counteract the buoyant force of
groundwater on the tanks. If less than 2 feet of backfill soil is placed over the tanks,
uplift of the tanks could occur when the tanks are empty, such as after pumping the
tanks empty for maintenance. We have assumed that the concrete lids of the septic tank
and dosing tank are about 2 feet below existing grade. If the tanks are placed deeper,
then the soil cover thickness may need to be increased and we should be notified to re-
evaluate the soil cover thickness. Septic tank and dosing tank risers and lids must be
watertight to prevent ground and surface water from entering the tanks. We
recommend that the riser lids be installed slightly above existing grade to prevent
surface water infiltration.
Dosing Pmnp: An Orenco P3005, three stage, 115 volt effluent pump, or equivalent
high head effluent pump capable of providing at least 21.6 gallons per minute (gpm) at
33.1 feet of total dynamic head (tdh) is suitable for this application. For design
purposes, it was assumed that the elevation difference from the dosing pump intake to
the distribution manifold in the mound absorption area is not more than 12 feet and that
the transport pipe length is not more than 40 feet. The pump performance curve for the
4-04 119
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Casey Concrete
. March 25, 2004
Page4
Orenco P3005, three stage effluent pump is shown on Figure 7. If a pump other than
the specified Orenco P3005 will be used, we should be provided with a pump
perfonnance curve to ensure it is suitable for the design.
The effluent pump will be controlled by a timer control panel and a combination of
high-water and low-water float switches. The high water (pump on timer over-ride)
and low water (pump off timer over-ride) floats will override the timer control of the
pump when effluent levels in the tank are at maximum and minimum levels. The low
water (pump off timer over-ride) float should be set at a level above the effluent pump
water inlet to prevent the pump from running dry. A high water alarm switch should
be installed in the dosing tank 3 to 6 inches above the high float position. The high
water alarm will provide audio and visual warning of a high water condition and should
be placed inside or on the office where it will be readily seen and heard. The
highwater alarm must be wired on a circuit that is separate from the pump circuit.
This system will provide a uniform dosing frequency and duration while improving the
performance of the sand filter. The timer should be set to provide a 75 gallon dose
every 12 hours. The timed dosing frequency is based on dosing each z.one only once
per day. Each z.one will receive about 68 gallons of effuent per dose (approximately
half the design flow of 136.5 gallons per day), assuming a drainback volume of about 7
gallons per dose from within the transport pipe. It is likely that a timed pump control
system is more expensive than a float control system. However, a timed pump control
system will help ensure that the sand filter is not hydraulically over loaded during peak
flow periods thus lengthening the service life of the absorption area.
Sewer and Effluent Piping: The sewer line from the residence to the septic tank
should not be less than the diameter of the building drain and not less than 4 inches in
diameter. The portion of the sewer line extending from 5 feet outside the foundation
404 119
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Casey Concrete
. March 25, 2004
Page5
should have a slope of at least 2 % except for the 10 feet of pipe immediately preceding
the septic tank which must be sloped between 0.5% and 2%. Clean-out pipe should be
installed in the sewer line adjacent to the foundation, adjacent to the inlet of the septic
tank, where the line bends at 90 degrees or more and at least every 100 linear feet of
pipe throughout the length of the line.
The transport pipe should be schedule 40 PVC and must be sloped to allow effluent to
drain back to the dosing chamber when the pump switches off. The transport pipe must
be bedded properly and placed with no low spots where effluent can freere in the pipe.
This should prevent effluent from freezing in the pipe. The Orenco V4402 distribution
valve must be installed at the high point and must be used in conjunction with a high
head pump for the switch to operate properly. The transport pipe must slope downward
from the distributing valve towards the dosing pump and the manifold supply lines to
each mne of the absorption area must slope downward away from the valve. The valve
should be installed inside a PVC riser vault lying between the two mnes of the
absorption area. The riser vault lid should be insulated to protect the valve from frost.
The absorption area manifold piping, and distribution piping layout are shown on
Figure 5.
The waterline should be encased in concrete or sealed inside scheduled 40 PVC for a
distance of at least 10 feet on either side of where it crosses the sewer pipe.
Absorption Area: The mound absorption area aggregate bed is designed to be 600
square feet and will be divided into two equal mnes dosed by a low pressure
distribution system. The aggregate bed containing the distribution laterals has
dimensions of 15 feet wide by 40 feet long and will be constructed over a sand filter 4
feet thick. The basal surface area of the mound where the sand filter meets the natural
soil is about 1, 736 square feet in sire. Therefore the application rate of effluent at the
404119
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Casey Concrete
. March 25, 2004
Page6
base of the mound could be as low as 0. 08 gallons per square foot per day, given
wetting of the whole filer. Absorption area calculations are shown on Figure 4.
The mound absorption area should be installed on a relatively flat excavated surface.
Excavation cuts at the uphill side of the excavation should not exceed about 2 feet.
Care must be taken during installation to ensure that the soils exposed in the absorption
area are not compacted. The excavation, once completed, should be scarified and left
open to allow the soils to air dry before the sand, aggregate and distribution piping are
placed. The sand should be placed in a loose lifts about 6 inches thick and compacted
by tracking or wheel rolling prior to placement of the next lift. A Mirafi 140N or
equivalent geotextile should be placed over the aggregate containing the distribution
pipe to help prevent clogging of the aggregate by fine soil particles. The total thickness
of the soil cap over the mound, including topsoil, should be a minimum of 1 foot with
the side slopes graded at a slope of 3H: 1 V or flatter. A minimum of 0.5 feet of
topsoil, suitable to support vegetation, should be placed over the entire soil cap. The
topsoil should be free of clay, which could prevent evaporation from the mound
surface. It is important not to plant large vegetation in and around the absorption area
and manifold piping as the roots may damage the distribution piping. We recommend
that the topsoil cap be re-vegetated as soon as possible with a drought tolerant grass mix
or other suitable grass seed mix.
Combination air vent/inspection ports should be installed at each corner of the mound
aggregate bed. The vent/inspection ports should be constructed of 4 inch diameter PVC
pipe installed to the bottom of the aggregate bed. The bottom 9 inches of pipe within
the aggregate bed should be perforated. The vent/inspection ports should extend a
minimum of 8 inches above the top surface of the mound and have ventilated removable
caps to allow ventilation and inspection. A plan view of the mound absorption area is
shown on Figure 5 and a mound cross-section is shown on Figure 6.
404119
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Casey Concrete
. March 25, 2004
Page?
The area surrounding the mounded absorption area should be graded to prevent any
standing water from ponding near the absorption area. All materials and installation
should meet the requirements of the Colorado State Board of Health• s Guidelines on
Individual Sewage Disposal Systems, Revised 2000.
ISDS Maintenance; The on-site ISDS will require maintenance. The level of
maintenance will vary with the complexity of the system and water use habits of the
users. We recommend that fats, oils, greases, paint, solids, water softener backwash
solution, water from hot tubs, and other constituents that can clog and foul collection
and disposal equipment are not disposed of in the residence drains. The mound
absorption area and any areas directly up gradient of it should not be watered
excessively by lawn irrigation systems or other means as the soils may become
hydraulically overloaded. Given the very low permeability of the snhsoils beneath
the mound ah!iorption area, it is critical that no water fixtures in the office leak.
U>akiog fixtures c:an easily bydnmliraDy over-load the subsoils below the
absorption area. The septic tank should be pumped whenever the sludge and scum
occupy one-third of the tank's liquid capacity and we recommend that the dosing tank
also be pumped at this time. The septage should be disposed of at an approved location.
The high water alarm float switch should be checked at least once per year to ensure
that it is working properly. In addition, the screen vault surrounding the dosing pump
or the effluent filter should be checked for any clogging and cleaned as necessary. We
recommend that an operation and maintenance manual be developed for the ISDS. The
ISDS should be operated and maintained as stipulated in the manual. If you desire our
services, we can prepare the operation and maintenance manual for the on-site ISDS.
l.ioritations: This design has been conducted in accordance with generally accepted
engineering principles and practices in this area at this time. We make no warranty
either express or implied. The conclusions and recommendations submitted in this
404119
Casey Concrete
. March 25, 2004
Page8
report are based upon the data obtained from the Profile Pit and percolation test holes
excavated at the locations indicated on Figure 1 and to the depths shown on Figure 2,
the proposed type of construction, and our experience in the area. Our findings include
interpolation and extrapolation of the subsurface conditions identified at the Profile Pit
and percolation test holes and variations in the subsurface conditions may not become
evident until excavation is performed. If conditions encountered during construction
appear different from those described in this report we should be notified at once so re-
evaluation of the recommendations may be made.
Based on site reconnaissance, it is our opinion that the designed location of the ISDS
does not violate any setback requirements established by the Colorado State Board of
Health, Guidelines on Individual Sewage Disposal Systems, Revised 2000. We
recommend that the position of the ISDS components, proposed office and setback
requirements be verified in the field by a Professional Land Surveyor licensed in the
state of Colorado.
This report has been prepared for the exclusive use by our client for the ISDS design
submittal process. We are not responsible for technical interpretations by others of our
information. As the project evolves, we should provide continued consultation and
field services during ISDS construction to review and monitor the implementation of
our recommendations, and to verify that the recommendations have been appropriately
interpreted. We recommend on-site observation of excavations, gravel and sand
placement, pipe and tank installation, and soil backfill placement by a representative of
the geotechnical engineer. Any field observations of the ISDS installation or other out
of scope work will be provided at additional cost.
404 119
Casey Concrete
March 25, 2004
Page 9
Please contact us for any necessary revisions or discussion after review of this report by
your local health department. If you have any questions or if we may be of further
assistance, please let us know.
Sincerely,
HEPWm-P~OTECHNICAL, INC.
Andy~
Reviewed By:
Ronald J. Uhle, P.E.
Associate
Attachments: Figures I through 7
404119
-'\;--'\,
I
I
-'\,
I
I I ACTT\IE DITCH ---..j I 5,J75'
PROPOSED 50D GAL,
IXlllCRElE DOSING TANK
ll1H ORENCO P~ 3-
STAGE EFfl.UENT PUllP,
CR EQUIVALENT
WAlER WElL
LOT 1
5,:J7D'
,--1-~
I I I
I I
I I
PROPOSED MOUND
!UlGREGAlEBED,
'511. x '40 ft.
ORENCO V44Cl2
AUlllllAllC lllSllilllUTTN~
VAL\IE INSTAU.ED IN
PYC VAULT
APPPROXllAlE TCE OF
OF TOPSOIL CAP I I ~ I ~--1-__,
........ ......,._ --... ._ ...... .......... .... --lllDI --
EXISTING
GARAGE
, ..
r
"' .,.
fllt • •• ,.., .
fllt. .,.
r-,
I
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T-11>
~
•1Ell UEI
111FMl:a1D1 .......... ..... .....,LIB __ ,..
•mr UEI ...,._ 41 WIT. Cllt' HEl9fT llllS
404 119 HEPWORTH -PAWLAK
GEOTECHNICAL, INC.
PROPOSED omcE, RIFLE COMMERCIAL CENTER
SITE PLAN
r ...
fllt ...
fllt . ..
...
"'
I
I
I
I
I
•ADD an. Rll
f.Mll 100 UL. I
DAY Dlml fLOI -·-CM.. I DAY.
FIGURE 1
' •
PROFILE PIT
0
5
10
LEGEND:
TOPSOIL; slightly anty, slightly sandy cloy, containing organics and roots, medium stiff,
moist, brown.
0
5
10
SILT (ML): clayey, sandy to very sandy, loose, moist, llght brawn. Contains pockets of sflty sand.
1.5 Inch diameter PVC pipe plezometer Installed to depth Indicated for groundwater lewl
monitoring.
NOTES:
1. The Profile Pit was excavated on March 3, 2004 with a mini-backhoe.
2. Location of the Profile Pit was measured approximately by taping from features on the site.
3. Elevation of the Profile Pit was not measured and log of the pit la drawn to depth.
4. The Profile Pit location and elevation should be considered accurate only to the degree
Implied by the method used.
5. The llnes between materials shown on the Profile Pit log represent the approximate
boundaries between material t)'Pes and transitions may be gradual.
6. No free water was encountered In the Profne Pit at the time of excavating.
Fluctuations in water 1111191 may occur with time.
404 119 HEPWORTH -PAWLAK
GEOTECHNICAL, INC.
PROPOSED OFFICE, RIFLE COMMERCIAL CENTER
LOG OF PROFILE PIT FIGURE 2
.
• PRE-SOAK
FROM TO
DATE 313/04 314/04
HOLE N0.1 TIME 1:30 12:15
TIME FALL RATE
(min) Cinl Cmin/inl
15 1/2 30 DIAMETER (in): 8
15 1/4 60 TOTAL DEPTH (in): 32
15 1/4 60 WATER DEPTH AT START (in): 8
15 1/8 120
15 318 40
15 1/4 60 TYPE OF SOIL: SLIGHTLY CLAYEY, SIL TY SAND
15 1/4 60
AVERAGE RATE Cmin/inl = ~
HOLE N0.2
TIME FALL RATE
(min) (in) (min/in)
15 1/32 480 DIAMETER (in): 8
15 1/32 480 TOTAL DEPTH (in): 32
15 1/32 480 WATER DEPTH AT START (in): 6
15 1/32 480
15 0
15 0 TYPE OF SOIL: SLIGHTLY SANDY, CLAYEY SILT
15 0
AVERAGE RATE <min/in)= >480
HOLEN0.3
TIME FALL RATE
Cm in) (in) Cmin/inl
15 1/4 60 DIAMETER (in): 8
15 1/8 120 TOTAL DEPTH (in): 32
15 1/8 120 WATER DEPTH AT START (m): 6
15 1/32 480
15 1/32 480
15 1/32 480 TYPE OF SOIL: SLIGHTLY SANDY, CLAYEY SILT
15 1/32 480
AVERAGE RATE (min/in}= 480
I SOIL PERCOLATION RA TE (min/in)= Approx. 4801
REMARKS: AVERAGE MPI BASED ON TEST HOLES 2 AND 3.
LOCATION OF TEST HOLES: SEE FIGURE 1
404 119 HEPWORTH -PAWLAK PROPOSED DFFlCE, RIFLE COMMERCIAL CENlER FIGURE 3 GEOTECHNICAL, INC. PERCOLA llON TEST RESULTS
ISDS AB!DRPI'ION AREA CALCULATIONS
In acoordance with Colorado State Board of Health, Guiddines on Individual Sewage Disposal
Systeim, Revised 2000, the absorption area was calculated using the lbllowing equation:
A =Q<e}
5
Where,
A = ab&>rption area in s1p1re feet
Q = estimited design flow e~ to 150% of average
daily sewage flow in gallom per day
t = &iii percolation rate in mirutes per incb
An estimated average How of 18.2 gallom/person/day for an office building was used fur the proposed
offux: building with five full titre ~oyees. Because the proposed office is a tmdular building with
a full kitchen, the average daily sewage flow was calculated as lbllows.
15 gallons/pennn' day
+ l.4 gallons/person/day for Garbage Disposal
+ I 8 pllm!IJlmnnlday for Didi Washer
Average lllily How = 18.2 gallons/person/day
It is assum:d that there are five office e~oyees. The caJmlattd design How is 150% of the average
daily flow which is calculated as follows:
Q = (18.2)(5)(1.5) = 136.5 gallom per day
The mmnded absorption area was calculated using a peroolation rate of 480 mimtes per inch and a
design How of 136. 5 gallons per day as 1i>Ilows:
A= 136.5 <480>"'-= 598.1 square feet
5
Tbe ISDS design includes a dosing device; however, no reduction in the absolption area sile will be
allowed because of the very low pemr:ability of the subsoils. Therefore, a IDOUllded absorption area
with an aggregate bed sile of 15 feet wide and 40 feet long, uuling (JOO square feet will be required.
The IDJUlldcd absolption area will be divided into twO 20nes dosed by a !llbm:rsible eftluett Jlllll1l.
Effluent flow to the twO 20DCS will be alta'nated by an CXeu:o V 4402 automatic distributing valve to
provide a hydraulic resting period between doses.
The septic tank ibr the office building sbookl have a minimun efli:ctive liquid tank capacity of 750
pllons, because increased retfDion titre in the septic tank increases eflluent quality. Tbe septic tank
will gravity reed to a 500 gallon dosing tank. Tbe subnnsible eftlumt purq> tim:r should be set to
provide about 75 g;illons per dose evtsy 12 hours. Therefore, eadl zone of the absolption area will be
dosed no IDOre than 1 titre per day. Each zone will receive about 68 gallons of effluent per dose
assuming an effluent draid>ack volume of about 7 gallom per dose. The absorption area aggreg;ite bed
is designed to be 600 SCJl8l'I! rett.
404 119 HEPWORTH -PAWLAK
GEOTECHNICAL, INC.
PROPOSED OFFICE, RIFLE COMMERCIAL CENTER
ISDS ABSORPTION AREA CALCULA llONS FIGURE 4
404 119
SOLID PVC CAPS
ON ENDS OF ALL
DISlRIBUTION
LATERALS
TOE OF SAND -----..f""<::::------------,---FIL TER SLOPE
EDGE OF AGGREGATE
BED
1• DIA. MANIFOLD PIPE
SLOPED DOWN AWAY
FROM ORENCO V4402
DISlRIBUTING VALVE
1" DIA. SOLID
SCHEDULE 40 PVC
MANIFOLD PIPE
INSTALLED LEVEL
1" DIA. PVC PIPE
WITH 3/16" DIA
PERFORATIONS ON
BOTIDM OF PIPE
0
SPACED AT 18 INCHES ----1----1-..i-
ON CENTER WITH FIRST
PERFORATION LOCA TIED
3 " FROM MANIFOLD
4" DIA.
PVC AIR VENT
INSTALLED VERTICALLY
TO BOTIOM OF
AGGREGA TIE BED.
BOTIOM g• OF PIPE
WITHIN AGGREGATE
I
I
I
I I
l-3!..l
40'
BED TO BE
PERFORATED. TOP
OF PIPE TO BE
COVERED WITH
REMOVEABLE VENTILATED
li...--------31'---------i
TOP CAPS. INSTALL
TOP CAPS A MINIMUM
OF 8" ABOVE
GROUND SURFACE.
56'
NOTES: 1. ALL PIPING AND INSTALLATION METHODS SHALL MEET COLORADO STATE BOARD OF
HEALTH, GUIDELINES ON INDIVIDUAL SEWAGE DISPOSAL SYSTIEMS, REVISED 2000.
2. DISlRIBUTION PIPES SHALL BE INSTALLED LEVEL AND IN LOCATIONS
SHOWN ABOVE.
HEPWORTH -PAWLAK
GEOTECHNICAL, INC.
PROPOSED OFFlCE, RIFLE COMMERCIAL CENTER
PLAN VIEW MOUND ABSORPTION SYSTEM
FIGURE 5
•
9 INCH 1HICK AGGREGATE SUCH 1HAT
6 INCHES OF AGGREGATE ARE BELOW
DISTRIBUTION PIPE AND 2 INCHES ARE
ABOVE PIPE. AGGREGATE GRADATION
AS SPECIFlED BELOW.
12 INCHES MINIMUM TOTAL SOIL
CAP OVER FlLTER SAND AND
GEOTEXTILE, GRADED AT 3H:1V
OR FLATTER. TOP 6 INCHES OF
SOIL CAP SHOULD BE TOPSOIL
SEEDED WITH A DROUGHT
TOL£RANT OR SUITABLE
GRASS MIX. MIR/\fl 1~ GEOTEXTILE
OR EQUIVALENT
4 FEET OF FlL TER
SAND WllH GRADATION
AS SPECIFlED BELOW.
FlLTER SAND SLOPE GRADED
AT 2H:1V OR FLATTER ->------15• ____ .., .. .,,
EXISTING
GROUND
SURFACE
~-------~ 31' -----------<--'
NOTES
APPROXIMATE 2 FOOT
CUT BELOW EXISTING
GROUND SURFACE TO
BOTIOM OF MOUND
NOTE: SCARIFY BOTIOM
OF MOUND
EXCAVATION AND
AU.OW TO AIR
DRY PRIOR TO
PLACEMENT OF
SAND.
1. AGGREGATE SPECIFlCATIONS
STANDARD SIEVE SIZE
2-1/2"
% PASSING BY WEIGHT
100%
404 119
1/2" 0%
2. FlL TER SAND SPECIFlCATIONS
STANDARD SIEVE SIZE % PASSING BY WEIGHT
3/4"
No.4
No.50
No.100
No.200
100%
60-100%
10-30%
0-1DX
0-3:1
EFFECTIVE SIZE = 0.25 -0.6mm
UNIFORMITY COEFFlCIENT 4.0 OR LESS
3. REFER TO COLORADO STATE BOARD OF HEALlH
GUIDELINES ON INDIVIDUAL SEWAGE DISPOSAL SYSTEMS,
REVISED 2000 FOR 01HER APPLICABLE SPECIFlCA TIONS.
HEPWORTH -PAWLAK
GEOTECHNICAL, INC.
PROPOSED OFFlCE, RIFLE COMMERCIAL CENTER FIGURE 6
MOUND ABSORPTION SYSTEM X-SECTION
~
.jo.
~
~
IO
G) :r:
fTl fTI
0 "ll
rrl ~ () ;v
I~ z
() I
> "ll r>
-~ z>
!'.">;.;:
0 "1l ;o :;o
fTlO z "1l
(") 0
0 f(l c
"llo ~:H Oo
.f11 f'1
VI <!!
J,~
:;;! 0
G)O
fTl ;i::
I:
"ll !:a
CQ ~j!!!
(") 0 c ,,,
;v z rii~ --,,
C5 c ;o
fTI
......
Pump Selection for a Pressurized System
Input Pilrwnet•r•
Orltlce Size 3111 lnche&
Rasidoat Hod at Last Orifice 5.00 feet
Orifice Spacing 1.1 feet
Number of Literals per Cel •
Laid length 11.1 feet
Lateral Line Size 1.00 Inches
Lateral ~ Cl88e/Schedule ••
C*tftbullng VM Model ....
Manifold Looglh 10.1 ,_.
Manifold Line Size 1.00 Nhea
Manifold Pipe Ctaaa/Schedule ..
Lift lD Manifold 12.D feel
T-Longlh .. o.a reet J
Tranapofl lN Size 2.00 lnct1M ~ Transport Pipe ClaaalSchedlP •• g Olechllrge Aaeernbti Stze 1.211 lnche8
flow Meter None Inches I 'Add-on' Friction losses 1.0 feel :c
-~ CelculMlons " MlnlmUm Flow Rate per Ofince 0.17 gpm ! Number of Orifices per Zone 22 li Total Adual Flow Rate 21.1 gpm ~ Number of Lines P8f Zone 2
"-'i Flow mtferanllal 181. and Lut Orifice 3.2 "
Lift lo Manifold 12.0 feet
Residual Head Ill lat Orifice 1.00 feel
Had Lou In Lat .... 0..4 feet
Head Lon Through Dl&trlbulS\g VaNe 7.3 feet
Head loaa In Manifold 0.7 feet
Head Loss In Transpoft Pipe 0.3 feet
Head Losa Tivough Discharge 2.3 feet
Head Loss Ttvough Flow Meter 0.0 feel:
'Add-on' Friction losses fi.O feet
Total Flow Rate 21.6 gpm
TOH 33.1 feet
PROPOSED OFFICE, RIFLE COMMERCIAL CENTER
2411 i 1------·I 1--1---I ....... A~·"·· --' ...... --~
0 I
0 10 20 JO 40
Net Discharge, gpm
~
~ .. .., ca
Orenco System
lncorporared
114 AIRWAY AVfNUE
SUTHERUN. DREGON
'""
TOllFREE
lmJI 3411-9843
TELEPHONE·
15411459-4449
FACSIMILE.
15411459-2884
wwworen.co.com
,,
'
HEPWORTH-PAWLAK GEOTECHNICAL
November 2, 2004
Casey Concrete
. Attn: Rob Willits
P.O. Box 1815
Rifle, Colorado 81650
11epworth~Pawlak Geotechnical, Inc.
P. 0. Drawer 1887
Silverthorne, Colorado 80498
Phone: 970-468-1989
Fax: 970-468-5891
email: hpgeo4@hpgeo[ech.c<nn
Job No. 404 119
Subject: A.a-Built Evllluation of Individual Sewage Disposal System, Existing Office Building,
Rifle Commercial Center, 28575 Highways 6 and 24, Garfield County, Colorado.
Dear Mr. Willits:
Hepworth-Pawlak Geoteclmical, Inc. bas observed the instidlation of the Individual Disposal
System (ISDS) for the Casey Concrete Office Building at 28575 Highways 6 and 24, Rifle
Commercial Center, as required by Garfield County. The ISDS components observed included:
absorption area excavation depth, 3 inch base course filter soil and thickness, septic tank, dose
tank, absorption bed aggregate, eftluent transport pipe and grades, sewer pipe and grades,
distnlrution laterals. dosing pump installation and Biotube screen vault, cleanouts, manifold pipes,
inspection ports, Orenco V4402 Automatic Distnlmting Valve, and the locations of all
components.
The septic tank was observed to be a 1,000 gallon two chamber concrete tank from Copeland
Concrete and the dose tank installed at the site is a 1,000 gallon single chamber concrete tank
which was also manufactured by Copeland Concrete. The transport pipe installed from the
Orenco P3005 dose pump to the Orenco V4402 Automatic DistributiDg Valve was observed to be
1.25 inch diameter schedule 40 PVC. Two inch diameter transport pipe was specified in the ISDS
design report, dated March 25, 2004; however, the 1.25 inch diameter transport pipe will peiform
equally well.
Clear sections of pipe are provided on the manifold outlets from the Orenco V4402 Automatic
Distributing Valve adjacent to the valve. These "windows" should be observed during dosing at
least once per year to ensure that the valve is alternating doses properly.
Glenwood Springs 970-945-7988 • Parker 303-841-7119 • Colorado Springs 719-633-5562
Casey Concrete
November 2, 2004
Page2
Based on our observations made during the site visits it is our professional opinion that the ISDS
was constructed in general accordance with the ISDS design report.
If you have any questions or if we may be of further assistance., please let us know. Please
forward one copy of this report to the Garfield County Environmental Health Department.
404119