HomeMy WebLinkAbout20180945.tiffArchitecture
Structural
Geotechnical
ROCKY MOUNTAIN GROUP
Job No. 155983
July 13, 2017
Gallacher Development, LLC
10465 Park Meadows, #107
Lone Tree, CO 80124
Attn: Kelly Gallacher
Attn: Kristen Jones
Re: OWTS Soil Evaluation and Design
Brighton Self Storage Phase 1
Brighton, Colorado
Dear Kelly,
Materials Testing
Forensic
Civil/Planning
Please find enclosed revised soil evaluation review and design for a proposed On -site
Wastewater Treatment System (OWTS) for the above referenced site. A representative of RMG
— Rocky Mountain Group performed soil evaluation of two soil profile test pit excavations on
June 12, 2017. The profile pits and soil evaluation were performed in accordance with Weld
County Department of Health and Environment On -site Wastewater Treatment System
Regulations (Regulations).
It is our understanding the vacant 35 -acre parcel of land is proposed to be developed for
commercial and retail uses. The proposed development will consist of self storage units, retail
businesses, a gas station and potentially a restaurant with a drive-thru. The preliminary plat map
indicated there was one area proposed to be the soil treatment area to serve all of the buildings
located in the northeastern portion of the site. A member from RMG completed test pits in this
area on March 8, 2017. Prior to the completion of that OWTS design, the client contacted RMG
and requested to relocate the OWTS to a new area located near the southwestern corner of the
proposed self storage units. Additionally, the new proposed OWTS will only serve the main
office of the self storage units. All other buildings constructed at this site will require separate
systems.
The soils evaluated in the profile pits are documented on the Test Boring Logs. The subsurface
materials generally consisted of six inches of clayey to sandy topsoil underlain by silty to clayey
sand. The silty to clayey sand extends to approximately three feet below existing grade where
sandy lean clay was encountered. The sandy lean clay extends to the final exploration depth of
TP-N at a depth of approximately eight feet below existing grade. In TP-S, the sandy lean clay is
underlain by clayey to silty sand at an approximate depth of five feet. The clayey to silty sand
Southern Office:
Colorado Springs, CO 80918
719.548.0600
Central Office:
Englewood, CO 80112
303.688.9475
Northern Office:
Evans, CO 80620
970.330.1071
www.rmgengineers,com
Monument: 719.48 8.2145
Woodland Park: 719.687.6077
Erbil/Kurdistan Iraq: 0750 192 99 44
Brighton Self Storage
Brighton, Colorado
that extends to the final depth explored of approximately eightfeetbelow existing grade. No
limiting zones were encountered to the depths explored.
The soil evaluation determined a soil type 3A in the zone of influence as described on Table 30-
10-1 of the Regulations. The OWTS should be designed using a Long Term Acceptance Rate
(LTAR) of 0.30 gallons per day per square foot for the soils in accordance with the above
mentioned table.
An engineer designed septic system will be required for this site due to it being used for a
commercial property. Additionally, the owner will have to meet the required distance criteria as
shown in Table 30-7-1 of the Regulations, enclosed. The location of the profile pits and
proposed Soil Treatment Area (STA) will be greater than all horizontal and vertical separation
distances as shown in Table 30-7-2.
it is our understanding the self storage units will have 1 employee per 8 hour shift. However for
design purposes, the anticipated daily flow was calculated for 5 employees per 8 hour shift.
Therefore, the system was designed in accordance with Table 30-6-2 of the Regulations with a
design flow of 75 gallons/day in accordance with Table 30-6-2, will consist of a minimum 500
gallon two compartment tank meeting the regulations outlined in Section 30-9-20. The system
was designed as an absorption bed usingeither chambers or rock and pipe as the distribution
media in an absorption bed. Both design options are provided below.
Absorption Bed with Chambers:
The adjusted required soil treatment area for a gravity bed using chambers is 210 square feet, see
enclosed calculations. The minimum number of chambers required is 18. The bottom of the
chambers should be placed between 24" and 36" below existing grade and will require
observation ports on each row of chambers.
Absorption Bed with Rock and Pipe:
The adjusted required soil treatment area for a gravity bed using rock and pipe is 300 square feet,
see enclosed calculations. The maximum width allowed for absorption beds is 12 feet.
Therefore, this system was designed as a 12 feet wide by 25 feet long absorption bed. The rock
material used must meet the specifications listed in Section 30-10-40 of the Regulations. As
such, the material used must be clean gravel ranging between 'A inch to 2 1/2 inch in size. The
gravel must completely fill the absorption bed and must extend a minimum of 6 inches below the
distribution pipe and a minimum of 2 inches above the pipe. The top of the placed gravel must
be covered with nonwoven, permeable geotextile meeting a maximum thickness rating of two
(2.0) ounces per square yard or equivalent pervious material. An impervious covering must not
be used. The bottom of the rock should be placed between 24" and 36" below existing grade.
We anticipate an approximate cover of 12" to 24" cover over the septic tank and a 12 to 18"
cover over the distribution box. Both the septic tank and distribution box must have access from
the surface.
RMG - Rocky Mountain Group
2 Job No. 155983
Brighton Self Storage
Brighton, Colorado
We arc not aware of installed systems on neighboring properties that may affect the placement of
the proposed OWTS. Furthermore, we are not aware of any existing easements or right-of-ways
that may conflict with the proposed OWTS. We found no location of any visible or known
unsuitable, disturbed, or compacted soils. With the location of the STA being across the drive
area from the building, the piping under the pavement will need to be protected from the traffic
loads. Some ways to protect the pipe would be to encase the pipe in a larger, stronger pipe,
encase the pipe in concrete, or a combination of both. Ultimately, it is the responsibility of the
installer to implement a system to protect the pipe. We anticipate this area to remain
commercial use for the foreseeable future. There were no difficulties encountered during the site
evaluation.
During system installation the subsurface conditions encountered in the soil treatment area
excavation may vary from those encountered in the profile test pits. Depth to bedrock and
groundwater may be different from depths reported in this report. If subsurface conditions
encountered in the construction of the system differ from those reported, RMG Engineers should
be retained to review the subsurface conditions.
The soil evaluation was conducted at the request of the client iii a location determined by the
owner of the dwelling. We hope this report will assist you with your needs. Pleasecontact us if
you have any questions concerning this matter.
Should you have questions, please do not hesitate to call.
Cordially,
RMG - Rocky Mountain Group
Lauren McIver, E I T
Geotechnical Staff Engineer
'Y f T?&
.
w •�
7/17/17
24995
Akcisis°4$ RP Duni its...
Thomas 1\4. Cope, P.E.
Sr. Geotechnical Engineer
a
RMG — Rocky Mountain Group
3 Job No. 155983
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VICINITY MAP
BRIGHTON SELF STORAGE
OWTS
CLIENT :
GALLAGHER DEVELOPMENT, LLC
10465 PARK MEADOWS, #I07
LONE TREE, CO. 80124
RICO PROJECT #155983
9tructurel • Geotechnical
RMG
ENGINEERS
ROCKY MOUNTAIN
GROUP
160137th STREET
EVANS, CO. 80620
PHONE: (970) 330-1071
FAX: (970) 330-1252
BRIGHTON, COLORADO
DATE: 7/6/17
N
\
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\` \� \
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WCR
0
60 120
SCALE: 1" = 1P0/
J�
BORE LOCATION
PLAN
BRIGHTON SELF STORAGE
BRIGHTON, COLORADO
CLIENT :
GALLAGHER DEVELOPMENT, LLC
10465 PARK MEADOWS, #107
LONE TREE, CO. 80124
RICO PROJECT #155983
DATE: 7/6/17
5tructurel • Geotechnical
ENGINEERS
ROCKY MOUNTAIN
GROUP
160137th STREET
EVANS, CO. 80620
PHONE: (970) 330-1071
FAX: (970) 330-1252
TEST BORING: TPN
DATE DRILLED:
6/12/17
REMARKS:
GROUNDWATER @ dry'
6/12/17
DEPTH (FT)
-'
0°
�
co
CO
a
Q
co
BLOWS PER FT.
WATER CONTENT %
TEST BORING: TPS
DATE DRILLED:
6/12/17
REMARKS:.
GROUNDWATER @ dry'
6/12/17
DEPTH (FT)
J
°°
�
co
w
a
co
BLOWS PER FT.
WATER CONTENT °/1
CLAY, sandy silty
dark brown, moist
CLAY, sandy silty
dark brown, moist
—
SAND, clayey silty
brown, fine, moist
�.'
;:
SAND, clayey silty
reddish brown, fine, moist
/
i'Y'•
CLAY, sandy silty
light brown, moist
CLAY, sandy silty
light brown, moist
5.0
5.0
7.5
�
SAND, clayey silty
brown, fine, moist
��
.
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.
7.5
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ROCKY MOUNTAIN GROUP
Architectural
Structural
Forensics
Colorado Swings: (CGrnorate Office",
2910 Ausit n Bluffs Parkway
Colorado Sp ngs, CO 80918
{7191, 548.0£00
SOUTHERN COLORADO, DENVER METRO. NORTHERN COLORADO
Geolechnical
Materials Testing
Give, Planning
TEST BORING
LOGS
JOB No. 155983
FIGURE No. 3
DATE 7/13/17
SOILS DESCRIPTION
\lfl.•.K
SANDY CLAY
SILTY, CLAYEY SAND
TOPSOIL
UNLESS NOTED OTHERWISE, ALL LABORATORY
TESTS PRESENTED HEREIN WERE PERFORMED BY:
RMG - ROCKY MOUNTAIN GROUP
1601 37TH ST.
EVANS, COLORADO
SYMBOLS AND NOTES
X
XX
STANDARD PENETRATION TEST - MADE BY DRIVING A SPLIT -BARREL SAMPLER INTO
THE SOIL BY DROPPING A 140 LB. HAMMER 30", IN GENERAL ACCORDANCE WITH ASTM
D-1586. NUMBER INDICATES NUMBER OF HAMMER BLOWS PER FOOT (UNLESS
OTHERWISE INDICATED).
UNDISTURBED CALIFORNIA SAMPLE - MADE BY DRIVING A RING -LINED SAMPLER INTO
THE SOIL BY DROPPING A 140 LB. HAMMER 30", IN GENERAL ACCORDANCE WITH ASTM
D-3550. NUMBER INDICATES NUMBER OF HAMMER BLOWS PER FOOT (UNLESS
OTHERWISE INDICATED).
FREE WATER TABLE
DEPTH AT WHICH BORING CAVED
BULK DISTURBED BULK SAMPLE
AUG AUGER "CUTTINGS"
4.5 WATER CONTENT (%)
Arc"- r ,ral
St;ctu•a
Fop"sirs
ROCKY MOUNTAIN GROUP ROCKY MOUNTAIN GROUP
Co,orado Springs: (Corporate Office)
2910 Ausain Burs Parkway
Colorado.Spings, CO 80918
(719) 548.0600
SOUTHERN COLORADO, DENVER METRO, NORTHERN COLORADO
Oeotcchnical
Materials Testing
Civil, Planning
Ner
EXPLANATION OF
TEST BORING LOGS
V
JOB No. 155983
FIGURE No. 4
DATE 7/13117
-A,
J
Structural .. Getttechnics1
ENGINEERS.
1601 37th ST. • EVANS, COLORADO 80620 • 970-330-1071 • FAX 970-330-1252
PROPOSED ESTIMATED CALCULATIONS
ON -SITE WASTEWATER TREATMENT SYSTEM
DESIGN FLOW
Office: 1: 8hr shift; 5 employees/shift
15 gpolemployee; 15 x 5
SEPTIC TANKS
48 hour detention
USE:
ABSORPTION BED
75 gpd Table 30-6-2
150 gallons
Minimum 500 Gallon Tank
Soil Treatment Area (STA) Required = Design Flow (gpd)
LIAR (gpd/sf)
75
0.30
Required Area = 250 sq. ft.
Gravity - Bed x 1.2
Chambers x 0.7
Adjusted Required Area Bed with Chambers
BED INFILTRATOR O CHAMBER EVALUATION
Allowable Area/Quick Four Infiltrator® Chamber = 12 per unit
Infiltrator® Chambers required: 210 sq. ft = 17.5 units
12 sq. ft/unit
Soil Type = 3A
LTAR=0.30
Table 30-10-1
Table 30-10-2
Table 30-10-3
Minimum Chambers = 18 units
210 sq. ft.
USE: 3 units wide x 6 Quick Four Infiltrator Units long
NOTE: INSTALL MIN. 18 H-10 QUICK -FOUR
INFILTRATOR UNITS IN ACCORDANCE TO
MANUFACTURER RECOMMENDATIONS.
OBSERVATION PORT (typ)
Riser Rings
Proposed
500 Gallon
Septic Tank
� � 1
Flow
distribution box
must extend _
to surface
2
Finished Grade
Inlet
Invert
Not lees
than 8.
ar MUG
than it
Sludge
20"
Monhde
•
te-
DISTRIBUTION
BOX
manhole risers
must extend
to surface
Plastic sweep "T"
!` or Baffle _ _ sum resat
Water Level
Cross
Over
O
A
5'
MIN.
(tyP)
4
zo"
Vent
fic
14"
Manhole
l
Tank
divider
Sludge
gr
0
a
SEPTIC TANK
NTS
Outlet
A
24'
MIN,
PLAN
NTS
A -A9
NTS
z
GD
155983-SEP
_______yll
ONS
T� WASTH THFAH I V \T SYSTI- M
BRIGHTON SELF STORAGE
WCP_2 &1NCRBRGON. COLOPADO
Structural • G el:techn ical
ENGINEERS
RM1G
ROCKY MOUNTAIN GROUP
1601 37TH STREET
EVANS, COLORADO 80620
(970) 330-1071
DATE:
PROW NO:
15598S
S
ALE:
1
DRAWN BY
CHECKED BY:
SHEET
OF 1,)
N
t
r
WCR
0
60 120
SCALE: 1" = 1P0/
\ \
• \ \
•
\ 5ti \\,N,
INC
St
.
J�
BORE LOCATION
PLAN
BRIGHTON SELF STORAGE
BRIGHTON, COLORADO
CLIENT :
GALLAGHER DEVELOPMENT, LLC
10465 PARK MEADOWS, #107
LONE TREE, CO. 80124
RICO PROJECT #155983
DATE: 7/17/17
5tructurel • Geotechnical
,
ENGINEERS
ROCKY MOUNTAIN
GROUP
160137th STREET
EVANS, CO. 80620
PHONE: (970) 330-1071
FAX: (970) 330-1252
Structural .. Getttechnics1
ENGINEERS.
1601 37th ST. • EVANS, COLORADO 80620 • 970-330-1071 • FAX 970-330-1252
PROPOSED ESTIMATED CALCULATIONS
ON -SITE WASTEWATER TREATMENT SYSTEM
DESIGN FLOW
Office: 1: 8hr shift; 5 employees/shift
15 gpolemployee; 15 x 5 = 75 gpd Table 30-6-2
SEPTIC TANKS
48 hour detention = 150 gallons
USE: 500 Gallon Tank or larger
ABSORPTION BED
Soil Treatment Area (STA) Required = Design Flow (gpd)
LIAR (gpd/sf)
75
0.30
Required Area 250 sq. ft.
Gravity - Bed x 1.2
Clean, Graded, '/2" to 2 1/�" Gravel x 1.0
Soil Type = 3A
LTAR=0.30
Table 30-10-1
Table 30-10-2
Table 30-10-3
Adjusted Required Area Bed with Rock and Pipe =
USE:
1 Absorption bed:
300 sq. ft.
12 feet wide (maximum width for beds per Regulations) x 25 feet long, minimum
6 inches of gravel meeting requirements listed in Section 30-10- 40 C. 1. a. of the
Regulations below distribution pipe and 2 inches of similar gravel above pipe.
OBSERVATION PORT (typ)
4" 0 PVC SOH 40
Flow
Proposed
500 Gallon
Septic Tank
Finished Grade
Riser Rings
4 .°'
20°
Manhole
distribution box
must extend
to surface
manhole risers
must extend
to surface
25'
20°
Manhole
Inlet
Invert
Plastic sweep "T"
or Baffle ,aqum at
Not less
than 6'
or more
than 17"
Sludge
Water Level
Cross
Over
t
Vent
mum mg-.
r,T �, ic
14° 1
Tank
divider
Sludge
Outlet
SEPTIC TANK
N TS
MIN,
PLAN
NTS
CLEAN GRADED AGGREGATE
1/2" TO 2-1/2" SIZE
MIN. 6" BELOW PIPE
MIN. 2" ABOVE PIPE
NON -WOVEN
PERMEABLE
GEOTEXTI LE
EXISTING SOIL
3' MAX
TRENCH
F
A -A
NTS
155983-SEP
_____)
ONSHE WASF HFAMH\ SYSHM
RHGHTO SELF ST RAGE
WCR7&WCR 19
I3HCHTOIL COLORADO
Structure) e Geotechnicel
RNIG
ENGINEERS
ROCKY MOUNTAIN
GROUP
1601 37TH STREET
EVANS, COLORADO 80620
(970) 330-1071
DATE:
PROW N
7/I'j17
155983
SCALE:
NJ�SS
DRAWN
Y°
°
T.M C.
CHECKED BY:
T. NI .
b
SHEET
OF
1
N
t
r
WCR
0
60 120
SCALE: 1" = 1P0/
\ \
• \ \
•
\ 5ti \\,N,
BORE LOCATION
PLAN
BRIGHTON SELF STORAGE
BRIGHTON, COLORADO
INC
St
.
J�
CLIENT :
GALLAGHER DEVELOPMENT, LLC
10465 PARK MEADOWS, #107
LONE TREE, CO. 80124
RICO PROJECT #155983
DATE: 7/17/17
9tructurel • Geotechnical
ENGINEERS
ROCKY MOUNTAIN
GROUP
160137th STREET
EVANS, CO. 80620
PHONE: (970) 330-1071
FAX: (970) 330-1252
Table 30-7-1
Minimum Horizontal Distances in Feet Between Components of an On -Site Wastewater TreatmentSystem
Installed After November 15, 1973 and Water, Physical and Health Impact Features
Spring,
Well,
Suction
Line
Potable
Water
Supply
Line
Potable
Water
Supply
Cistern
Dwelling
Occupied
Building
Property
Lines,
Piped
Lined
Irrigation
Ditch
or
Subsurface
Intermittent
Irrigation
Stormwater
Infiltration
Lateral,
Drywell,
Structure
Drain,
Course,
Irrigation
Stream,
Wetland
Lake,
Water
Ditch,
Dry
Cut
Fill
(from
Crest)
Gulch,
Bank,
Area
Septic
Tank
Septic
Tank,
Dosing
Higher
Level Treatment
Tank, Vault
Unit,
502
102
25
5
10
10
50
10
--
Building Sewer or Effluent
Lines
502
102
252
0
102
102
502
•
102
--
STA Trench, STA Bed, Unlined Sand Filter,
Sub -surface Dispersal System
100->
252
25
20
10
25
503
25
5
Lined Sand Filter
60
iO2
25
15
10
10
25
10
5
Lined Evapotranspiration
Berm of Lined Wastewater
Field
or Outside of
Pond
60
25
15
10
10
25
10
5
Unlined
Rate
or
Outside
or
Slower
Partially
System
Sand
than
Lined
of Berm
Not
Other
Filter
of
Relying
60
Evapotranspiration
in Soil
Minutes
Unlined
on
than Aerosol
With
Wastewater
STA
per
for
a Percolation
Inch,
Treatment
Unlined
System,
Pond,
100
25
25
15
10
25
25
15
10
Vault
Privy
50
102
25
15
10
10
25
10
--
System Not
Utilizing
Relying on STA for
Aerosol Methods
Treatment
and
1003
102
50
125
10
0
253
10
10
PAGE 49
2013-0173
ORD2013-13
Table 30-10-1
Soil Treatment Area Long-term Acceptance Rates by Soil Texture, Soil Structure, Percolation Rate and Treatment Level
Soil Type, Texture, Structure and Percolation Rate Range
Long Term Acceptance
(LTAR); Gallons per
square foot
Rate
day per
USDA Soil
USDA Soil
Percolation Rate
Soil Type
USDA Soil Texture
Structure
-Shape
Structure
-Grade
(MPI)
All Treatment Levels
Soil Type
1 with
more
than
Minimum 3 foot
deep unlined sand
0
35% Rock (>2mm);
Types -5 with
more than
Soil
--
Single Grain (0)
<5
filter
2
required ,
50% Rock (>2mm)
1.0 LTAR
1
Sand, Loamy Sand
--
Single Grain (0)
5-15
0.80
Sandy Loam,
Silt
PR (Prismatic)
BK
2 (Moderate)
Loam,
2
Loam
(Blocky)
GR (Granular)
3 (Strong)
16-25
0.60
2A
Sandy Loam, Loam, Silt
Loam
PR, BK, GR
0 (none)
1 (Weak)
Massive
26-40
0.50
3
Sandy Clay
Loam, Silty
Loam, Clay
Clay Loam
PR, BK, GR
2, 3
41-60
0.35
3A
Sandy Clay
Loam, Silty
Clay
Loam
PR, BK, GR
0
1
Massive
61-75
0.30
Loam,
Clay
.
4Sandy
Clay, Clay, Silty
Clay
PR, BK, GR
2, 3
76-90
0.20
Sandy Clay, Clay, Silty
Clay
PR,. BK, GR
0
14A
Massive
91-120
0.15
5
Soil Types 2-4A►
Platy
1,
2, 3
121+
0.10
Shaded areas require system design by a professional engineer.
1
Treatment levels are defined in Table 30-6-3.
2 Unlined sand filters in these soil types shall provide pathogen removal. Design shall conform to Section 30-11-30.B.3., Unlined Sand Filters.
PAGE 63
2013-**
ORD2013-13
GENFRAL NOTES
1. APPLICABLE CODES
A. These general notes apply to all septic drawings. This project is designed in
accordance with Weld County Environmental Health Department and the State of
Colorado most current codes and standards.
B. All materials and workmanship shall be in accordance with applicable provisions
of the codes specified above.
2. COORDINATION
A. DO NOT SCALE. The design is based on the OWTS Site Evaluation and Report
by RMG - Rocky Mountain Group for Gallacher Developments, LLC, Project No.
15593, last dated July 13, 2017. All changes to the design and layout are required
to be approved by the Engineer/Designer for inclusion into these plans. Any
discrepancies shall be brought to the attention of the Engineer/Designer
immediately.
B. Builders/owners shall review covenants to verify setback or land clearing
restrictions and requirements that may affect the system installation PRIOR to
construction.
C. RMG has provided this design in accordance v ith the standards of general
construction practices. However, as with all underground absorption fields,
guarantee against failure is impossible. With proper installation, as outlined for
this proposed construction, there remain many uncertainties and difficulties that
can still arise in the operation of the system in the future. Proper design,
construction and maintenance can assist in minimizing uncertainties but cannot
entirely eliminate. RMG provides no warranty of this design or installation.
3. INSPECTIONS
A. The Engineer/Designer inspections are separate from that which is required by the
County Health Department. The homeowner/contractor must ensure
all COUNTY and ENGINEER/DESIGNER inspections are completed.
B. Contact Engineer/Designer a minimum of 48 hours prior to schedule required
inspections.
C. The Engineer Inspections shall be as follows:
i. The Engineer/Designer shall inspect the installation of all components of
the septic system before backfill
ii. The Engineer/Designer shall inspect the components of the septic system,
after backfill to insure minimum cover, crowned top of field components
and proper drainage away from field.
4. SEPTIC SYSTEM
A. Maintain a minimum 1.0% and a maximum 5.0% grade on pipe feeding septic
tank and on pipe from field back to sump pit or pump station.
B. The homeowner/contactor is responsible for permit. The contractor must obtain
approval of the engineered/designed system from the County Health Department.
The homeowner/contractor must verify all setbacks and obtain utility clearances
prior to construction.
C. Vehicular and/or hooved animal traffic of any kind over any part of the system
may cause premature failure and is prohibited. The use of so called "septic
remedies" can result in severe damage to the system. We specifically recommend
against their use.
D. Provide a drainage sale or berm on the uphill slope of the absorption field or
treatment area.
E. DO NOT locate the absorption field or treatment area within 100 ft of well per
the County Health Department recommendations,
F. The field laterals may be curved to fit land contours. The minimum radius shall
be 100 ft.
G. Maintain all minimum setbacks and distances stated in this design and county
codes and standards.
H. Refer to all manufacture specifications prior to ordering and installation of
components.
I. Research indicates allowing the septic field to "rest" for several months may
increase its long term utility. RMG recommends resting each zone for three to six
months, systematically and sequentially cycling through each zone such that each
zone is idled for the recommended period every one to two years.
J. Irrigation is prohibited over the treatment area.
OPERATION AND MAINTH:NANCF,
INTRODUCTION
The individual septic system is not at all like a municipal sewer connection. A
connection to a public sewer virtually guarantees you will be able to send an almost unlimited
quantity of water, sewage and anything else down the drain with no particular problem,
However, with a septic system (more properly known as an On -site Wastewater Treatment
System, or OWTS, the amount of liquid we can send down the drain is distinctly limited. The
limiting factors are mostly the size of the system and the percolation rate of the soil in which the
absorption field is installed. Seemingly minor or even obscure factors such as how we wash our
clothes and the way we perform our daily routines can have significant effects on the functioning
of a septic system. In this paper, we will attempt to explain some of the more important aspects
of your septic system so you may have the best chance of attaining and maintaining a long-lived,
trouble free system.
INSTALLATION
Perhaps the most important element of a successful septic system is proper installation.
No amount of careful design and operation can overcome a poorly built system. Generally, a
licensed installer will be familiar with the various regulations relating to the installation. If you
perform your own installation, you absolutely must become familiar with certain specific
regulations. Check with your County Health Department well in advance of beginning your
installation to get the information and permits you will need to proceed. If you install an
engineered septicsystem, be aware the design is not a detailed, step-by-step guide. Many details
of the construction are omitted for the simplicity of the design, but are nevertheless required by
county regulations. Ask the engineer or Health Department for clarification if you are uncertain.
A good installer will additionally be a careful, conscientious craftsman who will go beyond the
minimums required by the county to provide a quality piece of work. Some of the big items you
should watch for in the installation of your system are: The soil under the septic tank should be
very well compacted to prevent the settling of the tank. The pipes should never go uphill unless
a pump is installed. The various lines of the distribution field should be level. If different levels
of the absorption field are used, there should be a device which will effectively distribute the
effluent between the various levels. The soil at the bottom of the field should never be
compacted; it should, after leveling, be roughed slightly to enhance the passage of water into it,
If a mound system is installed, the mound sand should be lightly compacted, usually by
sprinkling with water, to reduce settlement after the system is placed into operation.
GENERAL OPERATION
Practice water conservation as much as is practical. Repair leaking faucets and toilets
immediately; they can add hundreds of gallons of water per day of water usage. Avoid long
showers, run dishwashers only when full and run washing machines when full or at reduced
water settings.
Do not use the toilet as a trash can, Flushing a Kleenex or cigarette butt is wasteful of
water and serves to shorten the system life by adding unnecessary water to it. Do not, under any
circumstances, dump non -biodegradable materials, such as greases, plastics, etc., down your
toilet or drain. Absolutely never place harmful chemicals such as pesticides, paint thinner, oil,
antifreeze, etc. down the drains. These will kill beneficial bacteria that treat the wastewater.
Limit the use of bleaches, disinfectants and toilet bowl cleaners, as they will kill the bacteria as
well.
Divert surface water from driveways, hillsides and roof drains well away from the septic
system. Make sure outlets from sump pumps and foundation drains don't drain toward the
system.
CAUSES OF FAILURE
Most septic systems work well for many years; others both engineered and non -
engineered, fail relatively soon after installation. Many times the source of failure is difficult to
identify and it is generally recognized that certain number of systems will fail despite our best
intentions. This is because septic system stem design is not an exact science there are too many
variables and outside influences, which cannot be controlled or sometimes even predicted for us
to do much more than make educated guesses. System failure may result from too much water
being used, distribution field clogging may have occurred or the system may be operating at a
lower efficiency for a variety of complex reasons. The following discussion should acquaint you
with some of the more common sources of system failure. Knowledge of these sources should
help you avoid them.
Excess Water Use
The occupants of the house may be using too much water. The septic system sizing
formula was developed decades ago when water use habits resulted in generally much less water
use than is common today. Most county health regulations require the field to be upsized to
reflect usage of clothes washers and garbage disposals, but enforcement of the requirements is
generally based on whether the builder says these items will be installed or not. Installation of
clothes washers and garbage disposals after the fact can severely overload a system, if it is not
sized initially for that water use. Additionally the presence of teenagers in the house, with their
often two or more showers a day, is not reflected anywhere in any regulation. In an effort to
keep septic system prices down, installers often install the minimum system required by the
county. Builders and homeowners, under budgetary pressure, are generally very reluctant to
install any more than what is needed to meet code. Even engineered systems are usually not a
deal larger than required by code, as the price for larger systems escalates rapidly. Generally,
smaller systems have a shorter life span than larger systems.
Clogging
Clogging of the field by solid or greasy material washed out of the septic tank is another
source of failure. Solids (which are not always large, dense objects like sand, eggshells, coffee
grounds and the like but which are often more soupy, only -slightly -heavier -than -water
consistency) are meant to accumulate in the bottom of the tank, with greases floating to the top.
Septic tank performance is based on water slowly moving through the tank, allowing solids to
sink and greases to surface. If peak periods of water use occur where virtually the entire water
budget for the day is expended, such as washing two or three loads combined with all members
of the household bathing and flushing within a two hour period (a typical weekend morning in
many households), then turbulent conditions can exist which will wash out solids and greases out
of the tank. If these materials enter the distribution field, clogging will occur which will render
the entire system either less effective or completely worthless. The damage is generally
irreversible. There is no way to reliably determine whether this type of washout and subsequent
clogging has occurred, but it is safe to say it happens to some degree with almost all septic
systems at some point in their lifetimes. Regular tank pumping, at intervals not exceeding one to
two years, depending on the individual system, can help decrease the likelihood of this time of
trouble. Limiting periods of peak water use, by spacing out water use, will also help.
Profile Test Pit Limitations
The process to identify the soil type where the infiltration surface will be located is a
rudimentary practice and based solely on the soil technician's discretion. The soil technician is
trained to identify the various soil types in the field and must be qualified as a competent
technician according to country regulations; however, this does not increase the validity of the
soil interpretation beyond that of an educated opinion. The profile test pits are two small
excavations used to identify the soils within the soil treatment area and to locate groundwater
and/or bedrock. Due to the size differences between the profile test pit excavations and the soil
treatment area excavation, the soils encountered during the system installation may vary from
those identified in the profile test pits.
Furthermore, another item that is not quantifiable is the fact that the septic system is
essentially a biological machine. There are huge numbers of complex interactions between
various biodegradable and non -biodegradable constituents of the sewer water, the physical, and
chemical, organic and mineral makeups of the various soil components within the distribution
field and the incredible number of aerobic and anaerobic bacteria, which inhibit the entire septic
system. Certain laundry soaps or household chemicals may have no effect on one septic system,
but may cause poor performance in another, due to changes in the chemical and biological
makeup of the distribution field. The rate at which water moves between soil particles can
change over er months or years as soil reacts to the continuous influence of water and bacterial
action. There is no reliable way to predict these effects; the standard test pit excavation ation cannot
address the issue.
Compaction
Another cause of failure is compaction of the field after installation. Sometimes people
will view the green grass over the top of the septic field as a choice piece of pasture. Hoofed
animals exertgreat pressure with their feet and grazing over the top of a septic field will
generally result in compaction of the soil sufficient to render the system useless. Vehicle traffic
over the surface will cause similar problems with compaction; system crushing can also occur.
Vehicles (other than hand operated units) and hoofed animals are absolutely not compatible with
septic systems. Most counties health regulations specifically advice against vehicular and animal
traffic over the field.
SUMMARY
In conclusion, a septic system is not at all like a public sewer. Unlimited amounts of
sewage may not be placed into them impunity. Careful installation, with strict attention to detail
is essential to long-term success of the system. Even the best installation of a well -designed
system does not guarantee success. Surface drainage must be carefully maintained to avoid
inadvertent flooding of the septic system. Water conservation is essential, as is the avoidance of
placing poisons in to the system, individual septic systems are subject to a wide variety of system
failures that simply do not occur in normal, city sewers. The probable cause of most system
failures is a combination of factors. Most people use a lot of water; minimum systems are often
just not up to the task but upsized systems are generally not installed due to budgetary
constraints. Most families tend to peak load their septic systems. The septic tanks are not
designed to handle large quantities of water all at once; infrequent tank pumping increases
problems associated with large peak flows. Certain soaps, cleansers and other materials which
make their way down the drain may have adverse reactions with the bacteria in the septic system.
Many fields at one time or another are used as parking lots, pastures or worse. There often is
really no way to say for sure that any one particular thing causes failure. It is generally
recognized there are a certain number of systems that will fail for no good identifiable reason.
The best way to avoid failure is to treat your septic system as a valuable investment worthy of
protection. Minimize the liquid load, minimize the solid load and be careful about what goes
down the drain.
COLORADO
Department of Public
Health & Environment
Water Quality Control Division I Engineering Section
4300 Cherry Creek Drive S., Denver, CO 80246-1530
P 303.692.6298 I CDPHE.WQEngReviewstate.co.us
Accepted Septic Tanks for Use in Colorado On -Site Wastewater Treatment Systems
Company
Name
Tank Sizes
NPCA/IAPMO
Cert.
Notes
(Provided
specific
as an
acceptance
overview of Division acceptance.
letters for additional
Refer to
details)
ABC Concrete Mfg. Co., Inc.1508
1070, 1508, 1463
994,
No
Model
ABC
Gal.;
1-1000 = 1070
ABC 1500
Gal.;
= 1463
ABC
Gal.;
1000
All
= 994
Tanks
Gal.;
Double
ABC 1250
Comp.
=
Aguilar's
Concrete
750, 1000, 1250, 1500
NPCA
All
four tanks
are Double
Compartment
Anderson
Precast
1250, 1500
No
Both
Tanks
are Double
Compartment
Associated
Precast, Inc.
1000, 1250, 1500
No
All
three
tanks
are Double
Compartment
Beach
Concrete
1000, 1250, 1500
No
All
three
tanks
are Double
Compartment
Boughton's
Precast, Inc.NPCA2250,
1000, 1050LP
1250,
1250LP, 1500, 1500LP,
2250LP, 5000 HD
1000, 1250, 1500, 2250
1050, 1250, 1500, 1750 =
= Std.
low
double
profile,
P
double
-comp.
-comp.
tanks;
p
tanks
B.T.U. Block
a Concrete
1000, 1250
No
Both tanks are Double
Compartment
Chamberlain
Concrete
1500
No
Tank
is Double
Compartment
Copeland
Concrete
1000, 1250, 1500, 2000, 3000
No
All
tanks are Double
Compartment;
tanks
2000 and
3000 are mid
-seam
Copeland
Enterprises
1060, 1145, 1250, 1500, 2000, 2500, 3000
No
All
tanks
are Double
Compartment
Four Corners Precast
1000, 1250, 1500
NPCA
1000 D/C; 1000 D/C Low
lift station, 1500 3 -Comp.
D/C
Profile;
dosing
= Double
1250
siphon,
Compartment
D/C, 1500 D/C, 1500 3 -Comp.
2000 INC Traffic rated;
Front Range Pre -Cast Concrete, Inc.
400, 500,
1000, 1250, 1500, 2000, 2500,
3250
No
400, 500 = must
1000 = single
single,
and
be
used
double
double
along
comp.;
and
three
with
additional
All
compartment
other
tanks
tank
to
are accepted
tanks
meet
Reg.
43;
for
Green Brothers,
Inc.
1000, 1500
No
Both tanks
are Double
Compartment
Hi -Time Tanks
500, 1000, 1250, 1500
No
500 gal.
= must
43; 1000,
be used
1250,
along
and
with
1500
an additional
are all
Double
tank
Comp.
to
meet Reg.
Lindsay
Precast, Inc.
1000, 1250, 1500, 2250
NPCA
All
four tanks
are Double
Compartment
Gldcastle
Precast
1000, 1000LP, 1250, 1500, 2000
NPCA
All
tanks
are Double
Compartment,
LP = Low Profile
Precast Concepts
1000, 1250, 1500
No
All
three
tanks
are Double
Compartment
Ritchey's
Redi-Mix
Concrete
1000, 1500
No
Both tanks
are Double
Compartment
RMS Utilities
1250, 1500
No
Both
tanks
are Double
Compartment
Updated: 8/31/2016
1 of 3
COLORADO
Department of Public
Health & Environment
Water Quality Control Division I Engineering Section
4300 Cherry Creek Drive S., Denver, CO 80246-1530
P 303.692.6298 I CDPHEWUngReview@state.co.us
Accepted Septic Tanks for Use in Colorado On -Site Wastewater Treatment Systems
Company
Name
Tank Sizes
NPCA/IAPMO
Cert.
Notes (Provided
specific
as an
acceptance
overview of Division acceptance.
letters for additional
Refer to
detai Is)
San Luis Valley
Precast
500; 1000 LP, 1250 LP, 1500 LP, 2 and
3 lids
No
All
tanks
are Double
Compartment,
LP = Low Profile
500T, 500T-2CP, 1250M-2CP, 1250T-2CP, 1250T-1CP, 1250E-2CP;
1500M-2CP, 15OOT-2CP, 1500T-1 CP, 1500G-2CP, 1500G-1CP; 2000T -
Valley
Precast
500, 1000, 1250, 1500, 2000
No
vol.),
2CP, 2000T-1CP, 2000E-1CP,
1500G-3CP (2026 gal.
2000E-2CP; 1000T-3CP
vol.), 1500T-3CP (2026 gal.
(1500
vol.);
gal.
Note:
All
single
-comp. tanks must
be used
with an additional tank
to meet
Reg. 43. Note:
H-20 and
deep
-bury
tanks also
accepted.
Vaughn
Concrete Products,
Inc.
1000, 1250, 1500, 2000, 2500, 3000, 3500,
4000
NPCA
All
tanks
are Double
Compartment
p
POLY/PLASTIC TANKS
AK Industries
1000; 1000LP; 1300
IAPMG
All
1000
tanks
Gal.
are
LP
Double
=
Model
Compartment;
5-1050
Den Hartog Industries
Single
1000, 1250,
Et 2 -Comp.
1500;
for each
IAPMG
Single
and
Double
Compartment for each
p
tank
size
IM540 = Single
Comp.
w/1 Access; IM 1060 = Single
a Double
Comp.
Infiltrator
Water Technologies
1M-540, IM -1060, IM -1530
IAPMG
w/1 Et 2 Access Ports; IM1530 = Single
Et Double
Comp.
w/2 Et 3
Access Ports; Model
number
equals
working
volume
Norwesco
1000, 1250, 1500
IAPMG
All
tanks
are Double
Compartment; Br. = Bruiser Model
1000 -Br, 1250 -Br, 1500 -Br
Norwesco
- Snyder
:.
750, 1000, 1250, 1500; Low Profile Models
IAPMG
All
tanks
are Double
Compartment;
500 gal. and 750 gal.
(single
comp.),
750 (Double
comp.)
= must
be
Roth
Global
Plastics,
Inc. (Formerly
500, 750, 1000, 1060, 1250, 1500
I APMG
used
along
with
an additional
tank
to meet Reg. 43; 1000, 1060,
Fralo)
1250, 1500 = All
Double
Compartment
Snyder Industries,
Inc.
NuCon
Dom. 1000, 1250,
1050, 1250,
1500
1500
I APMG
All
tanks
are
low
Double
profile
Compartment;
tank;
NuCon is the
Dom.
standard
(Dominator
ribbed
Series)
tank
is a
Updated: 8/31/2016
2 of 3
COLORADO
Department of Public
Health & Environment
Water Quality Control Division I Engineering Section
4300 Cherry Creek Drive S., Denver, CO 80246-1530
P 303.692.6298 I CDPHEWUngReview@state.co.us
Accepted Septic Tanks for Use in Colorado On -Site Wastewater Treatment Systems
NPCA/IAPMO
Notes
(Provided as an overview of Division acceptance.
Refer to
Company
Name
Tank Sizes
Cert,
specific
acceptance
letters for additional
details)
Note: If a manufacturer is not NPCA or I APMO Certified, water -tightness testing data must be submitted to the Division by February 15 each year.
Updated: 8/31/2016
3 of 3
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