HomeMy WebLinkAboutEngineer's OWTS Design PlanSpgnnv ReSIDENCE
OWTS Rrponr
Spennv RestDENcE
GnnnELD Coururv, CotoRADo
June 2025
Prepared by
SSGM
118 West Sixth Street, Suite 200
Glenwood Spring+ CO 81601
970.945.1004
970.945.5948 tax
Sperry Residence June 2025
SpennY RESTDENCE
OWTS RTPORT
Spennv RTSIDENCE
GnnnELD CouNrY, CoLoRADo
"l hereby affirm that this Onsite Wastewater Treatment System (OWTS) report for Sperry Residence
Garfield County, Colorado was prepared by me, or under my direct supervision, for the Owners
thereof in accordance with the provisions of Garfield County's OWTS Regulations and approved
variances and exceptions listed thereto. I understand the County does not and will not assume
liability for OWTS facilities designed by others."
Jevon A. Poston, P.E License No.
Licensed Professional Engineer, State of Colorado (Affix Seal)
PRCPRRCO BV:
ZAcH WOLKEru, EIT
UnoTn THE SUPERVISION OF:
JEVON POSTON, PE
SGM Project # 2025-101 .001
ii
Sperry Residence June 2025
TnaLE OF CONTENTS
1.0 lntroduction
2.0 Preliminary lnvestigation
Property lnformation
Topography
Soil Data
Location of Physical Features
Additional Information
Landscape Position
Current and Historic Land Use
3.0 Summary of Detailed Soil lnvestigation
4.0 Recommendations
5.0 lnstallation Observations
6.0 Operation and Preventative Maintenance Schedule
7.0 Limitations
Appendix
Site Plan Sheet 1
OWTS Plan Sheet 2
OWTS Details Sheet 3
NRCS Soils Report
NRCS TexturalTriangle
OWTS Design Spreadsheet
Pump Gurve
Floodplain Map
CTLITHOMPSON Soils RePort
1
1
1
1
1
2
2
2
3
3
4
6
6
7
ilt
Sperry Residence June 2025
l.0lntroduction
This report has been developed for the subject property which:
. ls classified as Agricultural/Residential.
e ls comprised of 9.92 acres
. ls located at County Road 320 in Garfield County, Colorado'
It is proposed by the current owner for the construction of the property to include a 6-bedroom Elog
house with associated site work, drainage improvements, and utility services.
The purpose of this report is to present the preliminary investigation, reconnaissance information and
design for the onsite wastewater treatment system (OWTS) that will treat wastewater generated from
the proposed development, as required by Garfield County's Regulation 43 (Reg 43).
2.0 Preliminary lnvesti gation
Property lnformation
Phvsical Address: 5811 320 County Road, Rifle, Colorado 81650
Leqat Description: Section: 27 Township: 6 Range: 94 TR in the SENE 9.92 acres. The parcel
number is 217 527 1 00128.
Existino Structures: There currently exists a shed and trailer.
Domestic Water: Served by onsite well.
Topography
Topography in the vicinity where the new OWTS is proposed to be placed slopes from the
southeast to the northwest at an approximate slope of 3.3%.
$oil Data
According to the Web Soil Survey developed by the Natural Resources Conservation Service
(NRCS), ioils associated with the subject property are classified as map unit 50. NRCS soil unit
50 is Olney loam, which has grades of between 3 and 6 percent. NRCS soil data indicates soil
unit 50 is somewhat limited for septic tank absorption fields.
Plotting the percentages of clay, sand and silt published by the NRCS for soil unit 50 on the USDA
TexturalTriangle indicates the soilwould classify as a sandy clay loam and generally agrees with
test pit evaluation. Sandy clay loam soils have a classification of type 3. The test pit evaluation
provided by the geotechnical engineer indicates that soil classifies as a sandy loam with gravel.
Geotechnical engineer classification of soils was determined as a rocky R-1 type 2A soil. The
long-term application rates (LTAR) for type 2 and 24 soils are 0.60 and 0.50 gallons per dayper
squlre foot of area (gpd/ft2), respectively for treatment level (TL) 1. The maximum LTAR for R-1
soil is 0.8 gallons per day per square foot of area (gpd/ft2) and require pressure distribution with
a minimum 2-foot deep Unlined Sand Filter for TL 1.
1
Sperry Residence June 2025
Location of Physical Features
Physical features on the subject property that will require minimum horizontal setbacks are shown
in the following table. All distances are in feet.
Well
502
502 t
1 003
100
Potable Water
Supply Line
Structure with
Basement, Crawl :
Space, or Footing ,
Drains
Property Lines,
Piped or
Lined
lnigation
Ditch
Lake,
Water
Course,
lrrigation
Ditch,
Stream,
WetlandT
50
Septic; Tank
5
10
Septic Tank
Effluent
Line
STA
Unlined
Sand Filter
102
So
252
252 15
10
102
10
10
5
0 502
503
25
20
2Crossings or encroachments may be permitted at the points as noted above provided that the water or wastewater
conveyance pipe is encased for the minimum setback distance on each side of the crossing. A length of pipe with a minimum
schedute 40 iating (ASTM Standard D 3034-16 (2016 version)) of sufficient diameter to easily slide ovel 1!q completely
encase the conveyance must be used. Rigid end caps of at least schedule 40 rating (ASTM Standard D 3034-1 6 (201 6
version)) must be glued or secured in a watertight fashion to the ends of the encasement pipe. A hole of sufficient size to
accommodate the-pipe must be drilled in the lowest section of the rigid cap so that the conveyance pipe rests on the bottom of
the encasement pijle. The area in which the pipe passes through the end caps must be sealed with an approved underground
sealant compatible with the piping used. Other methods of encasement that provide equal protection are allowed but must be
approved by the local public health agency.
3Add eight feet additional distance for each 100 gallons per day of design flows between 1,000 and 2,000 gallons per day,
unless it can be demonstrated by a professional engineer or geologist by a hydrologic analysis or the use of a barrier,
consisting of a minimum 30 mil PVC liner or equivalent, that contamination will be minimized. lf effluent meets Treatment Level
3N and p-CPH has a maintenance oversight program in accordance with section 16.D. of this regulation, the distance addition
is not required. Flows greater than 2,000 gallons per day must be hydrologically analyzed for flow, velocity, hy-draulic head, and
other pertinent characteristics as means of estimating distances required to minimize contamination as part of the Division site
application and permitting process.
68uilding sewer installations shall meet the design requirements of the Colorado Plumbing Code.
Additional lnformation
a. Easements: Existing easements on site have been located and added to the survey, and
installation of this OWTS will not interfere with the operation or maintenance requirements
associated with any easement's purpose.
b. Floodptain Maps: According to FEMA (Federal Emergency Management Agency), FlRMette
08020513508, dated 1211511977, was not mapped. CWCB (Colorado Water Conservation
Board) data was observed in lieu of FEMA, and shows the project is not located within a flood
zone (Zone A).
Landscape Position
The landscape position for the STA is considered generally flat and the slope shape is planar (LL)
towards the northwest.
2
Sperry Residence June 2025
Current and Historic Land Use
The subject property has been historically used for agricultural and rural-residential and is
expected to remain so in the future.
3.0 Summary of Detailed Soil lnvestigation
A detailed soil investigation to determine the depth to the limiting layer, if any, and properly classify
the soil type was conducted on February 26th,2024, Visual evaluation of the two soil profile test pits
(p-1 and'P-2) was conducted in the field and samples collected from each test pit. Grain-size analysis
was utilized to classify the soil type that will receive wastewater effluent.
Test pits were excavated adjacent to the proposed location for the STA, see sheet 2 for locations.
Visual evaluations of both test pits were conducted under adequate light conditions with soil being in
an unfrozen state.
3.1 Visual Evaluation
The CTLITHOMPSON professional engineer, Ryan R. Barbone, excavated two test pits, P-1, and P-
2 with a trackhoe and pits were backfilled immediately after excavation operations were completed.
Test pit P-1 exhibited topsoilforthe first 0 to 8 inches. No horizon layers from the bottom of the topsoil
zone to the bottom of the pit were observed. A bulk sample was collected at a depth of 3-4 feet. The
pit was excavated to a depth of 8 feet, which was determined to be a sandy loam and loamy sand
with gravel.
Test pit P-2 exhibited topsoil for the first 0 to 8 inches. No horizon layers from the bottom of the topsoil
zone to the bottom of the pit were observed. Two bulk samples were collected at a depth of 3-4 feet
and 7-8 feet. The pit was excavated to a depth of I feet, which was determined to be a sandy loam
and loamy sand with gravel.
No test pit showed signs of:
r A limiting layero Presence of ground water. Soil observation logs and photos can be found in the appendix.
All measurements are from the ground surface'
3.2 Grain-Size Evaluation
On 212612Q24, CTLITHOMPSON conducted grain-size analysis on the soil samples collected during
the visualevaluation of the test pits.
Results of the soil gradation revealed:
1. Sandy Loam (Soil TYPe 24)
2. Loamy Sand with Gravel (Soil Type R-1)
3. Percent Rock in sample = 19o/o for P-1 and 40-5o/o for P-2
The soil inP-2was classified as type R1 due to the total percentage of rock being greater than 35%.
3
Sperry Residence June 2025
To determine the proper soil type, the USDA soil structure type and grade were used. The
following table shows the soil's USDA structure type and grade determine for the sample.
SAMPLE
P-1
USDA Soil
Structure Type
Massive
USDA Soil
Structure Grade
Weak
P-2 Massive Weak
According to Table 10-1, section 43.10 of Reg43, soil type 2A is the only type that can have
a massive structure type and a weak soil structure grade. As such, the soil to receive the
effluent waste is classified as soil type 2A based on the fines. Soil type 2A has a LTAR of 0.50
gpd/ft2 for the application of effluent treated to treatment level (TL1).
According to Table 10-1A, section 43.10 of Reg43, the overlying soil classification must be
classified as an R-1 soil due to P-2 having a rock content above 35%.
4.0 Recommendations
An OWTS as a wastewater treatment system is suitable for this site. The combined bedroom count
of the proposed and existing structures using the sanitary sewer system is 6 bedrooms. As such,
recommendations for the OWTS design for a G-bedroom system is made.
At a minimum, depending on the distribution media decided on for the STA, the OWTS shall have:
Gomponent 6-Bedroom
Septic Tank
Trenches with lt
2,000 Gallon
768ft2
Method of Effluent Aoolication Pressure Dosed
Distribution Laterals/Transfer Lines 1-112'Schedule 40 PVC
lnfluent Lines 4'SDR-35
Wastewater from the residence will be conveyed through 4-inch SDR 35 PVC line, by gravity, to a
new septic tank (Valley Precast 2,000 Gallon Top Seam - 2 Component with High Head Pump)
containing an Orenco PF500552 effluent pump. From the septic tank the wastewater will be pumped
through i-112" schedule 40 PVC transfer lines up to a Valley Precast 6402A automatic distribution
valve where it will then be evenly distributed into a soil treatment area with chambers (16 chambers
per trench).
The proposed development being considered is for a O-bedroom residence. Per Table 6-1 of Reg 43,
single family residence shall be designed for a daily flow rate of 75 gallons per occupant.
# Bedroom Occupancy (# of
Persons)
Wastewater Flow per
Person Design Flow (gpd)
t)I 75 675
The OWTS STA site elevation is approximately 5241feet above sea level (NAVD 88), and it will be
located as shown on sheet 2. The septic tank will be installed at a location that will meet setback
requirements in Table 7-1, Reg 43 and allow gravity flow from the proposed house to the tank, in
addition to having access for maintenance.
4
Sperry Residence June 2025
Sewer Pipe: lnfluent pipe from the proposed house to the septic tank shall be 4-inch solid wall SDR-
SS PVC installed at a minimum grade of 2 percent, maximum of 10 percent. Joints shall be solvent
welded. Cleanouts are required:
1) Within 5 feet of the proposed residence.
2) At spacing not to exceed 100 feet.
3) Upslope of two or more bends closer than 10 feet.
Transfer lines and distribution lines shall be sized per the requirements shown on the design
drawings, schedule 40 PVC pipe, and have orifices drilled per the spacing requirements shown on
the design drawings.
All g0 degree bends shall be constructed using two 45 degree fittings. The pipe shall be properly
bedded per the typical trench detail presented on sheet 3.
Septic Tank One new 2,000-gallon septic tank with a high head pump for a 6-bedroom count will be
useO; tne tank must have two bays. The tank must be on the Colorado Department of Public Health
and Environment's accepted septic tank list, and/or meet Reg 43 requirements. The tanks and lids
shall conform to current County OWTS regulations and be traffic rated. The tanks shall be installed
with insulated, watertight access risers having lids that can be secured. Risers shall meet the tank
manufacturer's requirements for type and installation. There shall be an effluent filter at the outlet of
the tank and its handle shallextend to within twelve inches of the lid.
The septic tank shall:
1) Be located down gradient of the house.
2) Have a covering of no more than 4-feet in depth, no less than 2-foot, measured from the top
of the tank lid to finished grade surface. A septic tank having a cover thickness less than 2.0-
foot or greater than 4.0- feet will not be allowed.
3) Be at a location accessible for pumping and maintenance-
Prior to installation of the tank, the installer must ensure tank placement will allow connection of the
tank's inlet invert to the piping from the house, without exceeding the minimum or maximum cover
depths over the tank.
Soi! Treatment Area: Using the criteria found in section 43J0 of Reg 43 the following table
summarizes sizing of the STA.
*Nu is based on a floor area ol 12 The number of infiltrators increase with a lesser floor area and
decrease with a greater floor area.
The STA shall be excavated as field conditions and bedroom count design require, using the following
guidelines:
5
Distribution
Media
Adjustment
Factor
STA
Size
(s0
No. Chambers
(12sflchamber)LTAR
Method of
Application
Adjustment
Factor
No.
Occupants
Daily
Design
Flow
(qpd)
No.
Bedrooms
Trench Treatment Area Usinq Chambers
0.7 756 63 Chambers6750.50 0.86I
Sperry Residence June 2025
1. Trenches shall be no wider than 3-feet.
2. Trench lengths shall be no longer than 1S0-feet.
3. A minimum of 4-feet, measured sidewall to sidewall, shall separate trenches.
4. The infiltrative surface shall be no greater than 4-feet from the surface.
S. Trench floors shall be level and set no deeper than the infiltrative surface.
6. Chambers shall be placed per the manufacturer's directions.
7. Distribution laterals used in a trench must be as close to the center of the trench as possible.
8. Distribution lines shall meet the requirements shown on the design drawings.
g. There must be a minimum of 24" of sand media below the distribution system.
10. A gradation of the sand media used must be provided where the gradation must be dated no
more than one month prior to the installation date-
11. The preferred sand media requirements are as follows; effective size: 0.25-0.60mm,
uniformity coefficient: < 4.0, percent fines passing #200 sieve: < 3.0.
j2.The maximum hydraulic loading rate shall be 1.0gal/sq.ft./day, or the long-term acceptance
rate of the receiving soil, whichever results in the larger area.
The STA shall have a final soil cover of 12" with soil that is suitable for vegetation, the top 2" being
topsoil, at a minimum per section 43.11.9.1. The surface of the STA shall be graded to divert
stormwater runoff from the soil treatment area and protected against erosion. No automatic sprinkler
system shall be installed over the STA. Vehicular traffic and livestock shall be kept off of the STA.
No landscaping, impervious surfaces or plastic sheeting can be installed over the STA, which will
reduce performance of the STA.
5.0 lnstallation Observations
lnstallation of the OWTS tank, pump, influenVeffluent lines, ADV and infiltrators shall be observed by
the design engineer. Our office shall be notified by calling 970-384-9058 at least three days in
advance-io schedule personnel for the observation inspection of these features. lnstallation of these
features should be substantially complete and ready to be backfilled prior to requesting individual or
simultaneous observation inspections for these features.
6.0 operation and Preventative Maintenance schedule
The goal of an operation and maintenance schedule is to observe the operation of and perform minor
mainienance to the onsite wastewater treatment system to allow for proper long-term functioning of
the system.
Septic tanks: The scum and sludge accumulation in the septic tanks shall be monitored yearly. Once
the cumglative scum or sludge thickness reaches 25% of the tank depth, the entire tank shall be
pumped. A pumping frequenCy of 1 to 3 years is expected at design flows. An alternative is a regular
pumping frequency of every 2 Years.
Efftuent Filten The effluent filter at the septic tank discharge shall be cleaned (hosed off) at the time
of pumping, or as needed.
Ftushinq Assemblies: Flushing assemblies, as shown on sheet 3, must be installed at the far end of
each lateral and must be accessible from the finished grade'
General: System users must realize that an on-site wastewater treatment system is different from
puOtic sewer service. There are daily considerations, such as not putting plastic or other non-
biodegradable material into the system. Water use shall be monitored so that toilets are not allowed
6
Sperry Residence June 2025
to leak when seals malfunction. Allowing fixtures to flow continuously to prevent water lines from
freezing is not acceptable. Although the proposed system can accommodate variable flows,
spreadi-ng water use over several hours and eliminating peak flows is recommended. To illustrate
the pointJa malfunctioning toilet can discharge in excess of 1,000 GPD. Excessive daily loading could
flood and irreparably harm the STA.
SGM recommends against installation of a water softener. The chemical and hydraulic loading from
the backwash of a water softener would be damaging to the STA, so if a softener is installed, a
separate drywell shall be constructed for the backwash waste. No landscaping or plastic can be used
over the STA, which would reduce the performance of the STA. The design of the OWTS is based
on the treatment of domestic sewage only. Swimming pool or spa water is not to be discharged into
the OWTS. The proposed OWTS design is based on the regulatory flows noted in the attached
calculations. lncreased flows may hydraulically or organically overload the OWTS, causing premature
failure.
7.0 Limitations
Our investigation, layout, design, and recommendations are based on site visits and the best
information ivailable at the time. The contents of this letter shall not serve as the basis for any third-
party engineering design. lf conditions that are considerably different from those described in this
l.eport ar6 encountered, SGM shall be called to evaluate the conditions. lf the proposed construction
is changed, SGM shall be notified to evaluate the effect of the changes on the OWTS prior to the
changei being made. All construction shall be in accordance with the Garfield County OWTS
Regr.ilations. Fipe type and size, burial requirements, septic tank construction, and other
spjcifications, which iie not depicted in our report, shall conform to the requirements of the County's
CjWfS Regulations. The installer of the system shall be acceptable by the County's Environmental
Health Department.
7
June 2025Sperry Residence
Appendix
"';+'3i::t3il::l
I
OWTS Details Sheet 3
NRCS Soils Report
NRCS Textural Triangle
OWTS Design Spreadsheet
Pump Gurve
Floodplain Map
CTLITHOMPSON Soils Report
8
wffiRa*wYMuffiffid
Sperry Residence
OWTS Plans
ESGM
1r8 W6t Si.th Stsl, Sune 200
ctsnv@d springe, Co 91601
w.sgclrc.M
---st+-
o
d
6
F
6
q
E\tq
'r/
lt
'i
l
\
i)
"l,f
\r
\
\
I
l
l
irg
F;
,6
).X\
t-
J?.-t
I('
.'i
I
a
a
I
4
q,
%
41
ai
5?2J
s4.s4
524
v2'Vu
tu4
52$
5231
a82
52$
52t
5235
52!a
t37
52S
3?J!
t''. .i;
.tz
J",P
{- t-t-. r,r, { 1_-r-..,!_/.
$'o
5?Q.
525r
525a
52U
52S
5256
5251
52$
gs
t(,
((
dlOIolu
e{
.s
i3
@KRHM,lRrcIffiffilI]]R
5
!N 9SGM
'1 18 West Sixlh Si@l, Suile 200
Glenwood Springs, CO 81601
970.9r5-1004
ww.sgm-inc.(m
Sperry Residence
OWTS Plans
--_@'t+-
o
a
d
d
8r2-
ags
22
e8,
-efl
3' r-
E9
;s
-P
F
I
ulll\
tcIo
qt
o
tiEise;H*a:l iE
"E3l;g
9F. !.
giq Ei
saE Es
it9 Fl-1d 2t16
iffi
sii
o
g
5
I
f
EI
o B3d
iHifid i6a
fiHatl:8;
Es! j
dEEF
ie{a
d5E6
eiiE
'l_ g*i!
iF;
83-
nE!
9{:qTt
dIi
$
Ht
l
0
f
I
gE
9;sf
:b
;E
qE
Eq
fll
iE
Eii
!Eti
EI
64
9"
I
F
sEEEE!i
i:!;E;E
g$!!!E:
9;saIel
'EFe;gg
EEEilg
azilcz
Ec;5;za46ci
nHF"s
rtPg
ulAguB{-
4Egi$
AEIHE
t!:B
nP=
3f;iFF! ig
cE:;
-ffagAEE
BEIs
E:45
Edl€
::EE
A^4-
r:He
r*i5
Eic
'.)
!clI:rt4
i:
tI
EE
a8
t
3
g-
F
EE
EE
1E
it*-
frn
13
161fgr
ze
x
T
5EE 6qr' dd.$
ren itE i*l
ffiiirleEi3l* !a: ::
ffE'iE ig
,16 B! :E
E!5 €D dd
lEa 6! E;
i:EEEt;
!E; i5 If
a3 33 cr
gE Ei i;
t
It
I
Ia
i
t
iFr
rg
I
ts
i
:.
a
;d3*i
seEIF
Fiig.xtcF:S +
ig;c
ddtr
:;iI
EB6it.5!
;Eed
irii
EE:E
E;8,
sd:E
bp;i
sli
rri$
- ^cti-tg
2
62
T-
e9
:
F
I
E
5
6
*
*
EI
2a
F9
A'
E
1
E
a
*
4
iiiE;ii;friti33_lr';iFa { I ? t-i il I g i!- i. t; t'; E eC $iiE'i
''tl
5232
E-
$,
b
n
isqed9
Fi'
Eig
9e3
;AE
alE
FrE
Esit
gsfr
S6-4.fr
;;
6
q3t
i:i
o
52U
t.
526
{
I
52f,6
q
s
I
I
I
I
Ea
Ee
t
0o
.66
E
l
3
q
"$"
l
I
!
,
a
I
I
I
I
I
I
I
F
,46
94
69
R?1<
P;
;T
"'F"
I
E
P
IEEgHroE
ef"
I
l9
sirB
$*
%
oEB
T;E
elnqFe
re
r-|'
$a
>EE
oiE
Oase
O{Es
E
.c
E
;I
ooc6ocs.gpfi
FIg.o
@
OffiS tuuils
3
r flML $tr trR rUS E Sre & @^M N ar ff 12' N *ffi,
MtrflIOE I'lM M Oi M?, &qtD uffir uY * M *ENDfrE]Mftffi, ASUTO$]ilIFfffiOFMK^N[NF&6 mfibE
A" INVERT
END CAP
P/N: Q4STDE
Plm d @& laDf, ile Meu6 r emr n ws fldE tux sme m rFe m*
MY ND IE&V M N A 6M ruI S RWIT Vffi *MfrE& mffi tgvr&.2 Sm]M MsSdTHt SSm*ilfitrS MS &lHMawEB&EsEmrM ue.
.. tr'#lfii.iffi\*8,
EAEIAEUEBIEEICtr-ISS:5ECIEtr
FLUSHING ASSEMBLY
rsMD mx r ffi Ar fiE $6& r.i nmu KE u,frrwffiMe6eEfcnfrffi,
OUICK4 STANDARD
lNSPECTION PORT
TYP1CAL INSTALLATION
DETAIL
(Nd b *dd
Option Ai CHAMBER RISER TO GRADE
rNFrLtilTOi WAF ]&&LOOTA
QUICK4STANDARD
MULTIPORT END CAPopiion Br INSTALUTIONWTHVALVEEOX
i!Eug[pB-.ut!Eq!ETD-UNE M-OUT Df,AL
I
\/
hnlffiEAW
hda
2O@ Galba Top Seam-2GP
H.rdwlllrhtffi
,8i$rFrm .d,aNtu
S.&r vltw
t l-rdlFtu
. dfi&dddft'd-
KMEffi
Effi,WdrUlffi.$-r.ts
TqW TAkW TehWffi# ffiffitr€f- \ nsdts:n\\m'/ \
rctuhrmd 6oq)Ssd6
ffiuffi \ l.trlnlat&oJlHdfrw ls-toogprnnovn#*s,; il
ffi"H.-Tf,i -Tu* *F-tuE-.-g+.:#_ q
mh .tsw
=9F-'
2-WAY SEWER CLEAN-OUT
USDA
=-
United States
Department of
Agriculture
A product of the National
Cooperative Soil SurveY,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Rifle Area, Golorado,
Parts of Garfield and
Mesa Gounties
NRCS
Natural
Resources
Conservation
Service
April2,2O25
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about tne properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soilsurveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifuing and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/n rcs/mai n/soils/health/) and certain conservation and engi neering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www. nrcs. usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcsl 42p2-053951 ).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
lnformation about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, maritalstatus, familialstatus, parentalstatus, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDAs TARGET Center al (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 lndependence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202)720-6382 (TDD). USDA is an equalopportunity
provider and employer.
3
Contents
Preface......
How Soil Surveys Arc Made...
SoilMap.....
SoilMap.....
Legend.......
Map Unit Legend........
Map Unit Descriptions
Rifle Area, Colorado, Parts of Garfield and Mesa Counties....
4$-Olney loam, 1 to 3 percent slopes'.-...'..
50-Olney loam, 3 to 6 percent slopes.'...'."
65-Torrifl uvents, nearly |eve|........'...
73-Water..
Soil lnformation for All Uses.........
Suitabilities and Limitations for Use...
Sanitary Facilities......
Septic Tank AbsorPtion Fields...
Soil Properties and Qualities.....
Soil Physical Properties.
Percent C|ay............
Percent Sand...........
Percent Si|t..............
Water Features.....
Depth to Water Table.......
References
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soilscientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soilsurvey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identiff soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
Custom Soil Resource RePort
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. lf intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to veriff the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
\A/hile a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. lnterpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soiiscientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
o
Custom Soil Resource RePort
identified each as a specific map unit. Aerial photographs show trees, buildings'
fields, roads, and rivers, allof which help in locating boundaries accurately.
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8
3
t
390 30?N
Custom Soil Resource Report
SoilMap
;
il
I
Q
Rp 390 30?N
3p 2953N
I
F
I
Eq
o
E
Ev
fi
e
39 2953N
N
A
3
il
M @ 2m M w
ltlap Scale: 1:2,100 f prinbd on A bndsope (11' x &5) sheet
lv€Els0s@1?o1&
FE€t01@2m,m6@
lvhp UoFdin: \ Eb Nlercabr Coner odinates: W@ Edge tics: UTM Zorc 13N WGS84
25m
=
il
t
9
2S4S 253S0 253S0 25ffi M
Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Please rely on the bar scale on each map sheet fcr map
measurements.
Source of Map: Natural Resources Conservation Service
\A/eb Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857i
Maps from the Web Soil Survey are based on theWeb Mercator
projection, which preserves direcfion and shape but distorts
distance and area. A projedion that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are requ;red.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
Survey Area Data: Version 17, Aug 29,2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25, 2021-Sep
5,2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably difiers ftom the background
Area ot hterest (AOl)
Solls
Area of lnterest (AOl)
Soil Map Unit Polygons
E SPoilArea
4 Stonyspot
ffi VeryStonyspot
S Wetspot
A Other
.- Special Une Features
Water Features
Streams and Canals
Transportauon
1a1 Rails
-
lnterstate Highways
ef US Routes
Major Roads
Local Roads
Background
I Aerial Photography
tv Soil Map Unit Lines
I Soil Map Unit Points
Speclal Point Featureg
Ql Blowout
El Bonow Pit
H Clay Spot
S Closed Depression
X Gravel Pit
; Gravelly Spot
& Landfill
I Lava Flow
db Marsh orswamp
# MineorQuarry
{B Miscellaneous \ hter
€ Perennial V\bter
csr Rock Outcrop
+ Saline Spot
:.: sandy spot
€ Severely Eroded Spot
$ Sinkhole
F Slide or Slip
@ Sodicspot
\A/aming: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
10
MAP LEGEND
Custom Soil Resource Report
MAP INFORMATION
imagery displayed on these maps. As a rcsult, sone minor
of unit boundaries be evident.
11
Custom Soil Resource Report
Map Unit Legend
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit^
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Wthin a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if evel can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties simihr to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. lf included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
Map Unit $ymbol Map Unit Namo Acres in AOI Percent of AOI
49 Olney loam, 1 to 3 percent
slopes
1.4 14.4o/o
50 Olney loam, 3 to 6 percent
slopes
6.7 67.0o/o
65 Tonifl uvenls, nearly level 0.6 6.0olo
73 Water 1.3 12.7%
Totals for Area of lnterest 10.0 100.0%
12
Custom Soil Resource RePort
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. lf intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol preCedes the map unit name in the map unit descriptions'
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soi/ sen'es. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement'
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use' On the
basis of such difierences, a soil series is divided into sorT phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps'
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An assocrafibn is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
13
Custom Soil Resource RePort
Rifle Area, Colorado, Parts of Garfield and Mesa Gounties
49-Olney loam, 1 to 3 Percent sloPes
Map Unit Setting
National maP unit sYmbol: inYi
Elevation: 5,000 to 6,500 feet
Farmtand ctassification; Prime farmland if irrigated
Map Unit Gomposition
Olney and similar soi/s: 85 Percent
Estimates are based on obseruations, desciptions, and fransecfs of the mapunit.
Description of Olney
Setting
Landform: Alluvial fans, valley sides
Down-slope shaPe: Linear, convex
Across-s/op e shaPe: Linear, convex
Parent materiat: Alluvium derived from sandstone and shale
Typical profile
Hl - 0 to 12 inches: loam
H2 - 12 to 33 inches: sandY claY loam
H3 - 33 to 43 inches: gravelly sandy clay loam
H4 - 43 to 60 inches.' very gravelly sandy loam
Properties and qualities
S/ope;lto3Percent
Depth to restrictive feature: More than 80 inches
D rai n age c/ass; Well drained
Runoff class; Low
Capacity of the most timiting layer to transmit water (Ksat); Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
FrcquencY of flooding: None
Frequency of Ponding: None
Calcium carbonate, maximum content: 15 percent
Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Avaitabte water supply, 0 to 60 inches: Moderate (about 7.6 inches)
Interpretive grouPs
Lan d cap abil ity classification (i nig ated) : 3e
Land cap abil ity cl assification (non i nig ated) : 3c
Hydrologic Soil GrouP: B
Ecotogicatsife: R048AY306UT - Upland Loam (\Afoming Big sagebrush)
Hydricsolrafing; No
14
Custom Soil Resource RePort
5O-Olney loam, 3 to 6 Percent slopes
Map Unit Setting
National map unit sYmbol: inYl
Elevation: 5,000 to 6,500 feet
Farmtand ctassification; Prime farmland if irrigated
Map Unit Composition
Olney and similar soi/s: 85 Percent
Estimates are based on obseruations, descriptions, and transects of the mapunit.
Description of OlneY
Setting
Landform: Alluvial fans, valley sides
Down-sloPe shaPe: Linear, convex
Across-s/op e shaPe: Linear, convex
Parent mateial: Alluvium derived from sandstone and shale
Typical profile
H1 - 0 to 12 inches: loam
H2 - 12 to 33 inches; sandY claY loam
H3 - 33 to 43 inches; gravelly sandy clay loam
H4 - 43 to 60 inches.' very gravelly sandy loam
Properties and qualities
S/ope:3to6Percent
Depth to restictive feature: More than 80 inches
D rain ag e c/ass: Well drained
Runoff class: Medium
Capacity of the most limiting tayer to transmit water (Ksat): Moderately high to high
(0.60 to 2.00 in/hr)
Depth to watertable: More than 80 inches
F req u ency of flooding: None
Frequency of Ponding: None
Catcium cahonate, maximum content:15 percent
Maximum salintty: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Avaitabte water supply, 0 to 60 inches: Moderate (about 7'6 inches)
lnterpretive groups
La nd capability cl a ssification (i nig ated) : 3e
Land capability classification (noninig ated) : 3c
Hydrologic Soil GrouP: B
Ecotogicalsife: R048AY306UT - Upland Loam (\Afroming Big sagebrush)
Hydic so/ rattng: No
15
Custom Soil Resource RePort
65-Torrifluvents, nearly level
Map Unit Sefting
National maP unit sYmbol: inz3
Etevation: 5,000 to 7,000 feet
Mean annual precipitation: 12lo 15 inches
Mean annual airtempenture: 46 to 48 degrees F
Frost-free peiod: 90 to 120 daYs
Farmtand ctassificatiou Not prime farmland
Map Unit Composition
Torrifluvents and similar sotTs; 85 percent
Minor components: 15 Percent
Estimates are based on obseruations, descriptions, and transects of the mapunit.
Description of Torrifluvents
Setting
Landform : Flood plains, rivers, distributaries
Down-slope shaPe: Convex, linear
Across-s/op e sh aPe: Convex, linear
P are nt m ate ri al : All uvium
Typicalprofile
H1 - 0 to 36 inches.' loam
H2 - 36 to 60 inches; sand
Properties and qualities
S/ope:0 to 6 Percent
Depth to restrictive feature: More than 80 inches
Drainage c/ass: Moderately well drained
Runoff class: Low
Capacity of the most timiting tayer to transmit water (Ksat); Moderately high to high
(0.60 to 2.00 in/hr)
Depth to watertable; About 12 to 36 inches
Frequency of flooding: Occasional
Frequency of Ponding: None
Calcium carbonate, maximum content:5 percent
Gypsum, maximum content:1 Percent
niaximum satinity: Very slightly saline to moderately saline (2.0 to 8.0 mmhos/cm)
Sodium adsorption ratio, maximum: 2.0
Avaitable water supply, 0 to 60 inches: Moderate (about 7.6 inches)
lnterpretive grouPs
Land cap abil ity cl assification (irig ated); None specified
La nd capabil ity cl assification (non i nig ated) : 7w
Hydrologic Soil GrouP: C
Hydric soil rating: No
16
Custom Soil Resource Report
Minor Components
Wann
Percent of map unit: 10 Percent
Landform: Terraces
HYdric soilrating: Yes
Fluvaquents
Percent of map unit: 5 Percent
Landform: Marshes
Hydric soilrating: Yes
73-Water
Map Unit Composition
Water:100 Percent
Estimates are based on obseruations, descriptions, and fransecfs of the mapunit.
17
Soil lnformation for All Uses
Suitabilities and Limitations for Use
The Suitabilities and Limitations for Use section includes various soil interpretations
displayed as thematic maps with a summary table for the soil map units in the
selected area of interest. A single value or rating for each map unit is generated by
aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each interpretation.
Sanitary Facilities
Sanitary Facilities interpretations are tools designed to guide the user in site
selection for the safe disposal of sewage and solid waste. Example interpretations
include septic tank absorption fields, sewage lagoons, and sanitary landfills.
Septic Tank Absorption Fields
ENG - Engineering
Septic tank absorption fields are areas in which effluent from a septic tank is
dishibuted into the soil through subsurface tiles or perforated pipe. Only that part of
the soil between depths of 24 and 60 inches is evaluated. The ratings are based on
the soil properties that affect absorption of the effluent, construction and
maintenance of the system, and public health. Saturated hydraulic conductivity
(Ksat), depth to a water table, ponding, depth to bedrock or a cemented pan, and
flooding affect absorption of the effluent. Stones and boulders, ice, and bedrock or a
cemented pan interfere with installation. Subsidence interferes with installation and
maintenance. Excessive slope may cause lateral seepage and surfacing of the
effluent in downslope areas.
Some soils are underlain by loose sand and gravel or fractured bedrock at a depth
of less than 4 feet below the distribution lines. ln these soils the absorption field may
not adequately filter the effluent, particularly when the system is new. As a result,
the ground water may become contaminated.
The ratings are both verbal and numerical. Rating class terms indicate the extent to
which the soils are limited by all of the soil features that affect the specified use.
18
Custom Soil Resource RePort
"Not limited" indicates that the soil has features that are very favorable for the
specified use. Good performance and very low maintenance can be expected.
"somewhat limited" indicates that the soil has features that are moderately
favorable for the specified use. The limitations can be overcome or minimized by
special planning, design, or installation. Fair performance and moderate
maintenance can be expected. "Very limited" indicates that the soil has one or more
features that are unfavorable for the specified use. The limitations generally cannot
be overcome without major soil reclamation, special design, or expensive
installation procedures. Poor performance and high maintenance can be expected'
Numerical ratings indicate the severity of individual limitations. The ratings are
shown as decimal fractions ranging from 0.01 to 1.00. They indicate gradations
between the point at which a soil feature has the greatest negative impact on the
use (1.00) and the point at which the soil feature is not a limitation (0.00).
The map unit components listed for each map unit in the accompanying Summary
by Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer
are determined by the aggregation method chosen. An aggregated rating class is
shown for each map unit. The components listed for each map unit are only those
that have the same rating class as listed for the map unit. The percent composition
of each component in a particular map unit is presented to help the user better
understand the percentage of each map unit that has the rating presented.
Other components with different ratings may be present in each map unit. The
ratings for all components, regardless of the map unit aggregated rating, can be
viewed by generating the equivalent report from the Soil Reports tab in Web Soil
Survey or from the Soil Data Mart site. Onsite investigation may be needed to
validate these interpretations and to confirm the identity of the soil on a given site.
19
=3 Custom Soil Resource Report
Map-Septic Tank Absorption Fields
39. 30 2'N
R
R 390 30'Z'N
390 29 53" N
E
I6
I6
$
o
P
g
e
F
e
B
e
2!;44
"ri;**--
xw 253@ 2s360 253/m gfi
Map Scale: 1:2,100 if printed on A lardscape (11" x 8.5") sheet.
0 30 60 1n 180
Feet
0 1@ 200 4m 6@
MapprojedionlWebMer@tor Comercoordinates:WGS84 Edgetics:UTMZonel3NWG$4
25m
B
fl
=
N
A
39. 29 53" N
20
253480 ?535n 253560 253600 w
Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
The soil suryeys that comprise your AOI were mapped at
1'.24,000.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projedion that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
SurveyArea Data: Version 17, Aug 29,2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25, 2021-Sep
5,2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
Area of lnterest (AOl)
I Area of lflterest (AOl)
Soils
Soil Rating Polygons
E Verylimited
I Somewhat limited
E Notlimited
n Notratedornotavailable
Soil Rating Lines
# Verylimited
, t Sornewhat limited
* Notlimited
t t Not rated or not available
Soil Rating Points
I Verylimited
tr Some\rhat limited
I Notlimited
tr Not rated or not available
Water Features
Streams and Canals
Transportatlon
Rails
Background
I AerialPhotography
t-H
4
-lj
lnterstate Highways
US Routes
Major Roads
Local Roads
\A/bming: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
21
MAP LEGEND
Custom Soil Resource Report
MAP INFORMATION
imagery displayed on these maps. As a r€sult, some minor
of unit boundarbs be
22
Custom Soil Resource RePort
Tables-septic Tank Absorption Fields
Rating Options-Septic Tank Absorption Fields
Agg regation Method : Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Map unit
symbol
lllap unit name Rating Component
name (percent)
Ratang reasons
(numeric
valuea)
Acres in AOI Percent ofAOl
49 Olney loam, 1 to
3 percent
slopes
Somewhat
limited
Olney (85%)Slowwaler
movement
(0.47)
1.4 14.4%
50 Olney loam, 3 to
6 percent
slopes
Somewhat
limited
Olney (85%)Slowwater
movement
(0.47)
6.7 67.0o/o
65 Tonifluvents,
nearly level
Very limited Tonifluvents
(85%)
Flooding (1.00)0.6 6.Oo/o
Depth to
saturated zone
(1.00)
Slowwater
movement
(0.47)
73 Water Not rated Water (100%)1.3 12.7o/o
Totals for Area of lnterest 10.0 r00.0%
Rating Acres in AOI Percent ofAOl
Somewhat limited 8.1 81.3%
Very limited 0.6 6.Oo/o
Null or Not Rated 1.3 12.7olo
Totals for Area of Interest 10.0 100.0%
23
Custom Soil Resource RePort
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and
qualities displayed as thematic maps with a summary talrle for the soil map ttnits in
the selected area of interest. A single value or rating for each map unit is generated
by aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each property or quality.
Soil Physical Properties
Soil Physical Properties are measured or inferred from direct observations in the
field or laboratory. Examples of soil physical properties include percent clay, organic
matter, saturated hydraulic conductivity, available water capacity, and bulk density.
Percent Clay
Clay as a soil separate consists of mineral soil particles that are less than 0.002
millimeter in diameter. The estimated clay content of each soil layer is given as a
percentage, by weight, of the soil material that is less than 2 millimeters in diameter.
The amount and kind of clay affect the fertility and physical condition of the soil and
the ability of the soil to adsorb cations and to retain moisture. They influence shrink-
swell potential, saturated hydraulic conductivity (Ksat), plasticity, the ease of soil
dispersion, and other soil properties. The amount and kind of clay in a soil also
affect tillage and earth-moving operations.
Most of the material is in one of three groups of clay minerals or a mixture of these
clay minerals. The groups are kaolinite, smectite, and hydrous mica, the best known
member of which is illite.
For each soil layer, this attribute is actually recorded as three separate values in the
database. A low value and a high value indicate the range of this attribute for the
soil component. A "representative" value indicates the expected value of this
attribute for the component. For this soil property, only the representative value is
used.
24
3I!
t
R
=
to
8.
M 25@0 53@ M 6W
Map Scale: 1:2,100 if prinEd on A landsape (1f x 8.f,) *teet
lvHets030601n1&
Fbet01@m4@60
lihp projedion: \ /bb l,lercabr C-orner coordhabs: WGS84 Edge tics: I,JIM zone 13N WGS84
Custom Soil Resource Report
MapPercent Clay
390 30?N 39.30?N
3!)o 2E 53. N
Iq
I
Es
I
Eq
oE
$
E
$
Ee
390 29 53 N
3
R
3
il
N
A
25@
25
M 253620 u38]25m M
MAP LEGEND
Area of lnterest {AOl)
Area of lnterest (AOl)
Solls
Soil Rating Polygons
n <=78
! > 7.8 and <= 20.5
tf Not rat€d or not available
Soil Rating Lines
X, <= 7.8
=
>7.8and<=20.5
. t Not rated or not available
Soil Rating Points
I <=7'E
I > 7.8 and <= 20.5
tr Not rated or not available
Water Features
Streams and Canals
Transportation
H-+ Rails
e lnterstate Highways
d* UsRoutes
- Major Roads
Local Roads
Background
I AerialPhotograPhy
Custom Soil Resource Report
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Please rely on the bar scale on each map sheet ftr map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857i
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves diredion and shape but distorts
distance and area. A projec{ion that preserves area, such as the
Albers equal-area conic projection, should be used ff more
accurate calculations of distance or area are requied.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
SurveyArea Data: Version 17, Aug 29,2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25, 2021-Sep
5,2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
\ /arning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
26
MAP LEGEND
Custom Soil Resource Report
MAP INFORMATION
imagery displayed on these maps. As a result, some minor
of unit boundaries be evident.
27
Custom Soil Resource RePort
Table-Percent Clay
Ratin g Options-Percent G laY
Units of Measure.' percent
Agg regation Method : Dominant Component
Component Percent Cutoff: None Specified
Tie-break Rule; Higher
lnterpret Nul/s as Zero: No
Layer options (Hoizon Aggregation Method): Depth Range (weighted Average)
Top Depth:24
Bottom Depth:60
Units of Measure.' lnches
Percent Sand
Sand as a soil separate consists of mineral soil particles that are 0.05 millimeter to 2
millimeters in diameter, ln the database, the estimated sand content of each soil
layer is given as a percentage, by weight, of the soil material that is less than 2
mittimeters in diameter. The content of sand, silt, and clay affects the physical
behavior of a soil. Particle size is important for engineering and agronomic
interpretations, for determination of soil hydrologic qualities, and for soil
classification.
For each soil layer, this attribute is actually recorded as three separate values in the
database. A low value and a high value indicate the range of this attribute for the
soil component. A "representative" value indicates the expected value of this
attribute for the component. For this soil property, only the representative value is
used.
Percent ofAOlAcres in AOIRating (porcent)Map unit nameMap unit symbol
14.4o/o'1.420.5Olney loam, 1 to 3
percent slopes
49
67.0o/o20.5 6.7Olney loam, 3 to 6
percent slopes
50
0.6 6.Oo/o7.8Tonifl uvents, nearly level65
1.3 '12.7o/oWater73
1OO.Oo/o{0.0Totals for Area of lnterest
28
3
\
=
Custom Soil Resource Report
Map-Percent Sand
V
@
3So 30 2" N p 390 30'2" N
3f 29 53'N
F
.*;
Ip
e
I
F
e
o
RF_s
.*$[ih
I
)
.: \;
25ffi 25eO w 253/10
Map Scale: 1:2,100 if printed on A landscape (11" x 8.5") sheet.
0 30 60 1n 180
,Feet0 lm 200 4m 6m
l4ap projection: Web Mercator Comer @odinates: WGS84 Edge tjcs: UTM Zone 13N WGS84
pI
aap*
'ni
/H't
t
I
I,
rd; b--tl 1
390 29'53" N
E=
B\lt
A
25ffi2536@
29
2534&)253520 253560 253640
MAP LEGEND
Area of lnterest (AOl)
t] Area of lnterest (AOl)
Solls
Soll Rding Polygons
t <=62'8
I > 62.8 and <= 78.9
n Not rated or not available
Soil Rating Lines
=
<=62.8
# > 62.8 and <= 78.9
. t Not rated or not available
Soll Rating Points
I <=62'8
t > 62.8 and <= 78.9
tr Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
lnterstate Highways
US Routes
Major Roads
Local Roads
Custom Soil Resource Report
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857i
Maps from the Web Soil Survey are based on the Web Mercator
projec{ion, whicfi preserves direction and shape but distorts
distance and area. A projec{ion that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or arca are requhed.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
Survey Area Data: Version 17, Aug 29,2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25, 2021-Sep
5,2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably difiers from the background
l'#
tryt
Background
I AerialPhotography
\A/aming: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a rnore detailed
scale.
30
MAP LEGEND
Custom Soil Resource Report
MAP INFORMATION
imaEery displayed on these maps. As a result, some minor
of unit boundaries be evident.
31
Custom Soil Resource RePort
Table-Percent Sand
Rati ng Options-Percent Sand
Units of Measure: percent
Aggregation Method: Dominant Component
Component Percent Cutoff: None Specified
Tie-break Ru/e: Higher
lnterpret Nu//s as Zero: No
Layer Options (Horizon Aggregation Method): Depth Range (Weighted Average)
Top Depth:24
Bottom Depth:60
Units of Measure.' lnches
Percent Silt
Silt as a soil separate consists of mineral soil particles that are 0.002 to 0.05
millimeter in diameter. ln the database, the estimated silt content of each soil layer
is given as a percentage, by weight, of the soil material that is less than 2
millimeters in diameter.
The content of sand, silt, and clay affects the physical behavior of a soil. Particle
size is important for engineering and agronomic interpretations, for determination of
soil hydrologic qualities, and for soil classification
For each soil layet this attribute is actually recorded as three separate values in the
database. A low value and a high value indicate the range of this attribute for the
soil component. A "representative" value indicates the expected value of this
attribute for the component. For this soil property, only the representative value is
used.
Map unit symbol Map unit name Rating (percent)Acres in AOI Percent ofAOl
49 Olney loam, 'l to 3
percent slopes
62.8 '1.4 14.4%
50 Olney loam, 3 to 6
percent slopes
62.8 6.7 67.0o/o
65 Tonifluvehts, nearly level 78.9 0.6 6.00/o
73 Water 1.3 12.7o/o
Totals for Area of lnterest 10.0 ,t00.0%
32
=
A
M 4s320 ffim M M
Plap Scale: 1:2,100 if prined on A lards@pe (11" x 8.5') *'eet.
MeErs0s@1n180
Feet0102@,m6m
lvhpproi:ction:\Ebltiercabr Corn€r@ordrEbs:WGS&+ Edgefs:UTMZonel3t{WGS84
Custom Soil Resource Report
Map-Percent Silt
390 3dZN 390 302'N
g
I
E€
I
€
o
R
E
$q
39p 2958N
N
A
=
il
25m
=
I
N
3
tu
I
33
M 4520 53$0 2m M
v 2959N
MAP LEGEND
Area of lnterest (AOl)
t] Area of lnterest (AOl)
Soils
Soll Rating Polygons
f <=13'4
I > 13.4 and <= 16.7
Not rated or not available
Soil Rating Lines
=
<=13.4
# >13.4and<=16.7
. t Not rated or not available
Soll Rating Points
I <= 13'4
I > 13.4 and <= 16.7
E Not rated or not available
W*er Featurec
Streams and Canals
Transportation
t+r Rails
lryt lnterstate Highways
*tt US Routes
Major Roads
Local Roads
Background
I Aerial Photography
Custom Soil Resource Report
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on theWeb Mercator
projedion, which preserves direc{ion and shape but distorts
distance and area. A projecfion that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are requ;red.
This produci is generated from the USDA-NRCS certified data as
of the version date(s) listed below
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
SurveyArea Data: Version 17, Aug 29,2024
Soil map units are labeled (as space allows) for n ap scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25,2021-Sep
5,2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably difers from the background
Waming: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
34
MAP LEGEND
Custom Soil Resource Report
MAP INFORMATION
imagery displayed on these maps. As a resuh, some minor
of unit boundaries be evident.
35
Custom Soil Resource Report
Table-Percent Silt
Rating Options-Percent Silt
Units of Measure.' percent
Aggregation Method: Dominant Component
Component Percent Cutoff: None Specified
Tie-break Ru/e: Higher
lnterpret Nu//s as Zero: No
Layer Options (Hoizon Aggregation Method): Depth Range (Weighted Average)
Top Depth:24
Bottom Depth:60
Units of Measure.' lnches
Water Features
Water Features include ponding frequency, flooding frequency, and depth to water
table.
Depth to Water Table
"Water table" refers to a saturated zone in the soil. lt occurs during specified
months. Estimates of the upper limit are based mainly on observations of the water
table at selected sites and on evidence of a saturated zone, namely grayish colors
(redoximorphic features) in the soil. A saturated zone that lasts for less than a
month is not considered a water table.
This attribute is actually recorded as three separate values in the database. A low
value and a high value indicate the range of this attribute for the soil component. A
"representative" value indicates the expected value of this attribute for the
component. For this soil property, only the representative value is used.
Map unit symbol Map unit name Rating (percent)Acres in AOI Percent ofAOl
49 Olney loam, 1 to 3
percent slopes
16.7 1.4 14.4o/"
50 Olney loam, 3 to 6
percent slopes
16.7 6.7 67.0o/o
65 Torrifl uvents, nearly level 13.4 0.6 6.0o/o
73 Water 1.3 12.7o/o
Totals for Area of lnterest 10.0 r00.0%
36
3
ilI
&.
E
il
M 25@0 re M bM
t\4ap Scale: 1:2,100 if prinbd on A brdscpe (11' x 8.y) sheet
lvtebls030@1n180
Fed01@n,mm
libp projectlxr: WEb lbrcabr Corneroordinabs: Wffi4 Hge ttcs: ttna Zone 13N W684
Custom Soil Resource Report
Map-Depth to Water Table
39c 30?N
ep*390 30 2'N
I
I
g
I
Ee
o
E
g
g
e
3f 29 53" N
N
A
25@
3
=F{
37
M 253520 5@ 2m 2S{0
v 29S'N
Custom Soil Resource Report
Area of lnterest (AOl)
Area of lnterest (AOl)
Soils
Soil Ratlng Polygong
o -25
25-50
50 - 100
100 - 150
150 - 200
> 200
Not rated or not availeble
tr Not rated or not available
Water Features
Streams and Canals
Transportation
{+t Rails
d lnterstate Highways
# USRouteS
,-- Major Roads
Local Roads
Background
I AerialPhotography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
'l:24,000.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857i
Maps from the Web Soil Survey are based on the Web Mercator
projeciion, which preserves direction and shape but distorts
distance and area. A projection thal preserues area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are requied.
This product is generated from the USDA-NRCS certified data as
of the vercion date(s) listed below
Soil Survey Area: Rifle Area, Colorado, Pails of Garfield and
Mesa Counties
Survey Area Data: Version 17, Aug 29,2024
Soil map units are labeled (as space allows) for nnp scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25, 2021-Sep
5,2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably difiers from the background
MAP LEGEND
T
E
f1
E
ffi
I
tl
Soil Ratlng Lineg
#
tg
*,
Soil Ratlng Points
o -25
25-50
50 - 100
100 - 1s0
150-200
> 200
Not rated or not available
I
tr
tr
T
Ir
o-25
25-50
50 - 100
100 - 150
150 - 200
> 200
\A/bming: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small aeas of
contrasting soils that could have been shown at a more detailed
scale.
38
MAP LEGEND
Custom Soil Resource Report
MAP INFORMATION
imagery displayed on these maps. As a resuh, some minor
of unit boundaries be evident.
39
Table-Depth to Water Table
Custom Soil Resource RePort
Percent ofAOlAcres in AOIRating (centimetera)Map unit nameMap unltsymbol
14.4'Yo1.4>200Olney loam, 1 to 3
percent slopes
49
67.0%6.7Olney loam, 3 to 6
percent slopes
>20050
6.0%61 0.6Torrifl uvents, nearly level65
1.3 12.7%>200Water73
10.0 100.0%Totals for Aroa of lnterest
40
Custom Soil Resource Report
Rating Options-Depth to Water Table
UniE of Measure.' centimeters
Aggregation Method: Dominant Component
Component Percent Cutoff: None Specified
Tie-break Rule; Lower
lnteryret Nu/ls as Zero; No
Beginning Month: January
Ending Month: December
41
References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and \Mldlife
Service FWS/OBS-79/31 .
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18,2002. Hydric soils of the United States'
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soilsurvey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U. S. Department of Agricu ltu re Handbook 1 8. http://www. n rcs. usda. gov/wps/porta l/
n rcs/detail/national/soils/?cid=nrcs1 42p2-054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soiltaxonomy. 11th edition. U.S. Department of
Agricultu re, Natu ra I Resou rces Conservation Service. http ://
www nrcs. usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and \Mldlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
h o me/?c id = n r cs1 42p2 _05337 4
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb 1 043084
42
ffi CTL ITHOMPSON
March 20,2025
(revised May 6, 2025)
Brian L. Sperry
2877 Loma Place
Boulder, CO 80301
Attention: Brian L. Sperry
Subject: Revised Site and Soil Evaluation
Sperry Residence
5811 County Road 320
Garfield CountY, Colorado
Project No. GS06951.000-1 32-11 R
CTllThompson, lnc. (CTLIT) was retained to perform a site and soil evaluation for
design of an on-site wastewater treatment system (OWTS) for the Sperry Residence proposed
at 5811 County Road 320 in Garfield County, Colorado. Design of the OWTS will be done by
other consultants. Our site and soil evaluation was conducted in accordance with the Garfield
County Onsite Wastewater Treatment System Regulations published by the Garfield County
Public Health Department.
The subject site is an approximately 9.92-acre parcel accessed by County Road 320 to
the east. A vicinity map with the location of the site is included on Figure 1. A shed and trailer
are present on the site. A new residence is planned on the west side of the lot on a terrace
about 15 feet above the Colorado River. An aerial photograph of the site is shown on Figure 2.
Trees and hydrophilic vegetation are present on the lot near the river with dryland shrubs and
grass at the central and eastern portions of the lot. An existing water well is located east of the
planneO residence. The proposed soiltreatment area (STA) is located in the south-central part
of the property to the south of the proposed residence location. A preliminary site plan with
proposed location of the STA is shown on Figure 3'
Ryan R, Barbone, P.E., of CTLIT visited the property on February 26,2025, to perform a
site and soil evaluation. The ground surface in the proposed STA area is generally flat and
slopes down to the west at grades less than 5 percent. The "slope shape" variable for the STA
classifies as "LL", pursuant to the EPA's Onsite Wastewater Treatmenf Sysfems Manual.
CTLIT investigated subsurface conditions in the proposed STA areas by observing two
profile pits (P-1 and P-2) that were excavated with a trackhoe at the approximate locations
shown.on Figures 2 and 3. Subsoils exposed in our profile pits consisted of approximately 8-
inches of topsoil over sandy loam with gavel and loamy sand to the total excavated depth of I
feet. Graphic logs of subsurface bonditions found in our profile pits are shown on Figure 4.
We did not find limiting layers in the subsoils, Groundwater was not encountered in our
profile pits at the time of excavation. No redoximorphic features were observed in the pits. We
observed that the soil had weak to no structure per the USDA Soil Structure - Shape and was
considered "massive" per USDA Soil Structure - Grade'
son. lnc.
Denver, Fort Collins, Colorado Sprinqs, Glenwood Sprinqs, fu.b]c, Summit Countv - Colorado
Chevenne, Wyoming and Bozeman, Montana
ffi
We performed grain-size analysis on two samples of soils obtained from our profile pits.
The soils encountered in our profile pits classified as sandy loam with gravel (Soil Type R-1,
Matrix Soils Type 24) and loamy sand (SoilType 1). We found a maximum gravel (>2mm)
content of 42 and 26 percent in P-1 and P-2, respectively. Descriptions of these soil types are
summarized on Table 10-1 and Table 10-1A of the OWTS design regulations published by
Garfield County. Gradation test results are included as Figure 5.
We are available to discuss the contents of this letter. lf you have questions or need
additional information, please call.
CTLITHOMPSON, I Reviewed by
L..tu
Kimberly Talbert
Staff Geologist
kta I bert@ctlt hom ps o n. co m
Attachments: Figure 1 - Vicinity Map
Figure 2 - Aerial PhotograPh
Figure3-ProPosedOWTS
Figure 4 - Summary Logs of Profile Pits
Figure 5 - Gradation Test Results
Via email: brianlsperrv@omail.com
BRIAN SPERRY
SPERRY RESIDENCE
CTLIT PROJECT NO. GS06951.000-132-L1 R
tu a.
Division Manag
Page 2 of 2
ffi
o 500 1000 NOTE:
SC,ALE: 1' - 1O0O'
BRIAT{ SPEBRY
SPERRYFESIDENCE
SATELLITE IMAGE FROM MAXAR
(coPYRrcHT 2025)
rt
Vicinity
MapoTUT PROJECT NO. GSO6951 .OOO-132-L1 Flg. 1
LEGEND:
P_1 APPROXIMATE LOCATION OF
I PROFILE PIT
ffi
o 50 100 NOTE:
SCALE: 1'- 100'
BRIAN SPERRY
SPEBBY FESIDENCE
oTUT PROJECT NO. GSO6951.000-1 s2-L1
SATELLITE IMAGE FROM GOOGLE EARTH
(DATED JUNE 25, 2023)
Aerial
Photograph Flg. 2
LEGEND:
P-1 APPROXIMATE LOCATION OF
I PROFILE PIT
NOTE:
ffi
o 50 100
SCALET 1'- 100'
BASE PI-ANS PROVIDED BY SGM
(DATED FEBRUARY 07, 2025)
-or';lF'.10-
nl
'6'
52r7.O'
6/:0291
6r
P-1
I
/
\ slr'rX
Proposed Residence
!0' t!$i (*tut
''/,-
P-2
Proposed STA
IJ,
7'
Gtltn tfit
ffor0
10ll€n ur
F!r0
EtnfrfF. fi05ER
BBLAN SPEBRY
SPERRY BESIDENCE
oTUT PROJECT NO. GSO6951 .OOO-1 3,2-L1
Proposed
owrs
nt'^:l'
l-.lt :.tu' i
;'
I
,r..j,u.
i
r:dr
.$
Flg. 3
F
lr.Jt!lr
zo
l--
LuJ
UJ
F
LU
UJlr
zIF
UJJ
I.IJ
5245
5240
5235
5230
P-1
EL.5242
P-2
EL.5241
LEGEND:
NOTES
5245
5240
5235
5230
h
TOPSOIL, CLAY, SANDY, ORGANICS, MOISTTO
VERY MOIST, SOFT, DARK BROWN,
SANDY LOAM AND LOAMY SAND WITH GMVEL,
WEAK TO STRUCTURELESS GRADE, LOOSE
coNgtsTENCY, MO|ST, TAN. (SOILTYPE R-1,
SoTLTYPE 1)
INDICATES A BULK SAMPLE FROM EXCAVATED
sorLs.
ffi
Summary Logs of
Profile Pits
PROFILE PITS WERE EXCAVATEO WITH A
TRACKHOE ON FEBRUARY 26,2025. THE PITS
WERE BACKFILLED IMMEDIATELY AFTER
EXCAVATION OPERATIONS WERE
COMPLETED.
2. SOIL EVALUATION CONDUCTED BY RYAN
BARBONE, P.E. (CPOW SOILS CERTIFIED)
3. GROUNDWATER WAS NOT ENCOUNTERED IN
PROFILE PITS AT THE TIME OF EXCAVATION.
REDOXIMORPHIC FEATURES WERE NOT
OBSERVED IN PROFILE PITS.
4. ELEVATIONS WERE ESTIMATED FROM
GROUND SURFACE ELEVATION CONTOURS ON
FIGURE 3.
5. THESE LOGS ARE SUBJECT TO THE
EXPLANATIONS, LIMITATIONS, AND
CONCLUSIONS IN THIS LETTER.
''r2
')2
BRIAN SPERRY
SPERRY RESIDENCEcTllr PROJECT NO. GS06951.000-132-Ll FIG.4
ffi
GRAVELSANDS
COARS FINE COARSE COBSLESCLAY (PljSTIC) TO SrLT (NON-PLASTTC)
FINE MEDIUM
ANALYSIS SIEVE ANALYSIS
2rooo
se0
Fz
u50
e.
UJ0-40
30
20
10
0
'4
90
80
100
70
80
90
'100
.001 0.002 .005 .009 .019 .o37 9-52 19.1 36.1 74.2 127'-200
152
TIME READINGS
60 MtN. 19 MrN. 4 MlN. 1 MlN. '200
U,S, STANDARD SERIES
'100 '50 '40 '30 '16 '',10'8
CLEAR SQUARE OPENINGS
3t8" 3t4" 1%', 3" 5"8" 8"
0
10
20
o30 uJz
340tut
F
50fro
&,U60 o-
.074 .'t49 .297 .590 1.19 2.0 2.38 4.76
o.42
DIAMETER OF PARTICLE IN MILLIMETERS
25 HR. 7 HR.
45 MrN. t5 MtN.
Somp|e of SANDY LoAM WITH GRAVEL - SOIL TYPE R-1
From P.1 AT 34 FEET
GRAVEL
stLr a cLnY
PLASTICITY INDEX
cRAVEL 20 o/o
slLT & CLAY 16 o/o
PLASTICITY INDEX
SAND 42
lrouro Ltrr,tn
To
%o
%
35 o/o
Zg o/o
Somple of
From
LOAMY SAND WITH GRAVEL - SOIL TYPE 1
P.2 AT 3-4 FEET
SAND
LIOUID LIMIT
64 o/o
o/o
%
BRIAN SPERRY
SPERRY RESIDENCE
PROJECT NO. GS06951.000-1 32-Ll
Gradation
Test Results
GMVELSANDS
COBBLESclAy (pl-AsTlc) To srLT (NoN-PLAsTlc)
FINE MEDIUM COARS FINE COARSE
10
20
30
40
50
00
70
80
90
100
--1
--1
-----t--
'F
(Jto
z
@
$oFz
850tru,o'ao
127 200
152
'4
90
80
100
.001 0.002 .005 .009 .019 .037 9.52 19_1 36_t 76.2
TIME CLEAR SOUARE OPENINGS
3t8" 3t4" 14', 3' 5'6"
U,S. STANDARD SERIES
'50'40 '30 '16 '10 '8
30
20
'10
0 .o74 .149 .297 .590 1.19 2.0 2.38 4.74
0.42
DIAM€TER OF PARTICLE IN MILLIMETERS
60 MtN. 19 MtN. 4 MtN. 1 MtN. '200 '100
25 HR. 7 HR.
45MtN. t5MtN.
FIG, 5