HomeMy WebLinkAboutEngineer's OWTS Design Plan
Geo Quest Project No. 25-143
Date: 9/9/25
Jaime Covarrubio
578 Canyon Creek Drive
Glenwood Springs, CO
(909) 538-4399
jaime_0910@hotmail.com
RE: Onsite Wastewater Treatment System (OWTS) Soil EvaluaƟon
Dear Mr. Covarrubio,
Geo Quest was asked to perform a soil evaluaƟon for a new OWTS at the property described as:
Garfield County Parcel 217711102002
86 NaƟve Springs Drive, Rifle, Colorado
This memo presents the evaluaƟon details and USDA soil type encountered at the property on
Monday, September 1, 2025. This informaƟon may be used in OWTS design.
Soil EvaluaƟon
Two soil profile test pits, idenƟfied as Test Pit 1 (TP-1) and TP-2, were excavated near the north
east corner of the property, near the proposed OWTS site. The excavaƟons were completed
with a Bobcat mini excavator to maximum depths of 8 feet below ground surface and approxi-
mate locaƟons are shown on the aƩached Test Pit LocaƟon Map.
RepresentaƟve soil samples were collected from the material layers encountered in the test
pits. These samples were evaluated and classified using the USDA Soil Texture and Structure
methods. The USDA classificaƟons were applied to the guidance document from Colorado De-
partment of Public Health & Environment, RegulaƟon No. 43, Table 10-1 as presented below.
The soil was very moist below 5 feet with saturated soil and ground water encountered in the
test pits at a depth of 7 feet.
Table 10-1 - Soil Treatment Area Long-Term Acceptance Rates
Soil
Type
Soil Tex-
ture
Soil Struc-
ture-Type
Soil Struc-
ture-Grade
PercolaƟon
Rate
(MPI)
Treatment
Level 1
2A Sandy
Loam Granular Structureless 26-40 0.50
Respecƞully submiƩed,
Geo Quest, LLC
Kevin E. Dye, P.E.
Figures: Boring LocaƟon Map, Logs
Approximate Test Pit LocaƟon map
9/9/25
TP-1
TP-2
Proposed OWTS Site
PROPOSED
BARN/SHOP
PROPERTY LINE PROPERTY LINE
PR
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EX. SHED
W
1
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0
'
S
B
1
0
0
'
S
B
100
'
S
B
10
0
'
S
B
10
0
'
S
B
1
0
0
'
S
B
1
0
0
'
S
B
10
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'
S
B
100'SB
100'SB
100
'
S
B
10
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'
S
B
10
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'
S
B
100' WELL SETBACK
WELL
OP
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N
D
I
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INSTALL 1000-GALLON
TWO-COMPARTMENT SEPTIC
TANK WITH AN EFFLUENT
FILTER IN THE OUTLET RISER
(SEE SETBACK NOTES)
C/O
TP
TP
APPROX. TEST PIT
LOCATION, TYP.
APPROX. TEST PIT
LOCATION, TYP.
INSTALL A TWO-WAY
CLEANOUT OUTSIDE
THE BUILDING
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20' MIN.
FROM
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≥50' FROM DITCH
5' MIN. FROM
FOUNDATION
5' MIN. FROM
FOUNDATION
>10' FROM
PROPERTY LINE
INSPECTION PORT AT EACH
END OF EACH LATERAL, TYP.
NOTES:
PROPERTY LINES ARE BEYOND THE
MAPPED AREA.
LOCATIONS OF ALL COMPONENTS MAY
BE VARIED AS NECESSARY AS LONG AS
ALL MINIMUM DISTANCES AND SLOPES
MEET THOSE REQUIRED.
GEOTECHNICAL ENGINEER TO CONFIRM
SOIL PROFILE AT THE CONSTRUCTED
LOCATION PRIOR TO INSTALLING THE
CHAMBER UNITS.EX. BARNEX. HORSE
RIDING
SHELTER
EX. GRAVEL DRIVE
EX
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EX. COVERED STORAGE
(NO FOUNDATION)
37110DERIC J O N WA
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COL O R A D O LICE
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SSIONA L E N G INEER
9/22/25
00 30'60'
Scale: 1" = 30'
NORTH
923 Cooper Avenue, Ste. 201
Glenwood Springs, CO 81601
tele: 970.945.5252
www.bu-inc.com
Engineer or Surveyor Seal
Sheet
Client Information:
Project No.:
Filename:
Designer:
Drafter:
Date:
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Subsurface Utility Engineering (SUE)
Required Project:
If "Yes", SUE Certification by:
Firm:
Job #:
Date:
Agency Approval
Agency:
Dept:
By:
Date:
Comments:
RevisionDate
9/22/25
RTC
DJW
25031-v-topo.dwg
25031
909.538.4399
GLENWOOD SPRINGS, CO 81601
578 CANYON CREEK DR.
JAIME COVARRUBIO
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SURFACE
12"
8'
±
5'
±
MAINTENANCE NOTES
1.TO ENCOURAGE THE HEALTH AND LONGEVITY OF THE OWTS SYSTEM, THE OWNER SHALL CONSIDER THE
FOLLOWING:
1.A.MINIMIZE THE AMOUNT OF WATER THAT GOES DOWN THE DRAIN, THE BETTER YOUR SYSTEM WILL
WORK.
1.B.MINIMIZE SOLIDS GOING DOWN THE DRAIN.
1.C.ELIMINATE GARBAGE DISPOSALS OR KEEP THE USE OF GARBAGE DISPOSALS TO A MINIMUM.
1.D.MINIMIZE GREASE AND OILS THAT GO DOWN THE DRAIN.
1.E.USE LINT FILTERS ON LAUNDRY MACHINE DRAINS.
1.F.KEEP SAND AND DIRT OUT OF THE BUILDING DRAIN.
1.G.AVOID FLUSHING SANITARY NAPKINS OR PAPER PRODUCTS OTHER THAN TOILET PAPER.
1.H.DO NOT USE LYE-BASED DRAIN UNCLOGGER CHEMICALS SUCH AS DRAINO, OVEN-OFF, OR OTHER
STRONG CLEANING AGENTS.
1.I.DO NOT PUT ANY “ROOT DETERRENTS” DOWN THE DRAIN.
1.J.DO NOT POUR PAINT THINNER, PESTICIDES, PAINTS OR PHOTO LAB CHEMICALS DOWN THE DRAIN
1.K.MINIMIZE USE OF CHLORINE BLEACH AND TOILET ADDITIVES.
2.THE OWNER SHALL CONTRACT WITH A SEPTIC TANK INSPECTOR TO INSPECT THE TANK ANNUALLY FOR
GREASE AND SEDIMENT ACCUMULATION. THE INSPECTOR SHALL REMOVED AND PROPERLY DISPOSED OF
ACCUMULATED GREASE AND SEDIMENT AS NEEDED TO ENSURE PROPER FUNCTION OF THE SYSTEM.
86 Native Springs
County of Garfield,
State of Colorado
Parcel No: 2177-111-02-002
I-70
Vicinity Map
Rifle
SITE
ATTACH REMOVABLE CAP OR
THREADED CLEANOUT ASSEMBLY.
INSTALL MARKER IF CAP IS TO
BE BURIED.
FINISH GRADE
4"Ø PVC RISER
4"Ø PVC TWO-WAY
CLEANOUT TEE
4"Ø SEWER LINE
12" SQ. NYLOPLAST H-20
SOLID COVER ASSEMBLY
REMOVABLE PVC CAP
FLUSH WITH SURFACE
24"x24"x6" CONCRETE
IN LANSCAPE
IN HARDSCAPE
To Silt
TOPSOIL
SANDY LOAM
(SAND, SILT, CLAY, BROWN, MOIST)
INCREASING MOISTURE BELOW 5'
NOTES:
THIS PLAN SET IS INTENDED TO BE PLOTTED IN
COLOR. FAILURE TO DO SO MAY RESULT IN MISSING
DATA & INFORMATION CRITICAL TO THE PROJECT.
SITE EVALUATION
1.SITE AND SOIL EVALUATIONS WERE PERFORMED BY:
DERIC J. WALTER, PE KEVIN DYE, PE
BOUNDARIES UNLIMITED INC.GEO QUEST
923 COOPER AVE., STE. 201 PO BOX 1372
GLENWOOD SPRINGS, CO 81601 RIFLE, COLORADO 81650
970.945.5252 970.318.6784
2.EVALUATION DATE(S): SEPTEMBER 1, 2025.
3.SOIL WAS CLASSIFIED BY THE GEOTECHNICAL ENGINEER (GEO QUEST (PROJECT
#25-143, SEPTEMBER 9, 2025) AS USDA SANDY LOAM; TYPE 2-A; WITH AN
LTAR OF 0.50 GPD/SF.
4.SETBACK REQUIREMENTS FOR A TREATMENT LEVEL 1 STA TRENCH/BED,
UNLINED SAND FILTER OR SEEPAGE PIT (PER TABLE 7-1) AND AN ADWF=560
GPD:
4.A.SPRING, WELL OR POTABLE CISTERN=100'
4.B.POTABLE WATER SUPPLY LINE=25'
4.C.STRUCTURE W/ BASEMENT/CRAWL SPACE=20'
4.D.STRUCTURE W/O BASEMENT/CRAWL SPACE=10'
4.E.PROPERTY LINE, PIPE OR LINED IRRIGATION DITCH=10'
4.F.INTERMITTENT IRRIGATION LATERAL, INFILTRATION STRUCTURE=25'
4.G.LAKE, WATER COURSE, IRRIGATION DITCH, STREAM OR WETLAND=50'
4.H.DRY GULCH, CUT BANK OR FILL AREA=25'
4.I.SEPTIC TANK=5'
4.J.RESTRICTIVE LAYER OR GROUNDWATER (VERTICAL): 4' (TREATMENT LEVEL
1, GRAVITY FEED)
3.SETBACK REQUIREMENTS FOR THE SEPTIC TANK SHALL BE (PER TABLE 7-1):
3.A.SPRING, WELL OR POTABLE CISTERN=50'
3.B.POTABLE WATER SUPPLY LINE=10'
3.C.STRUCTURE W/ BASEMENT/CRAWL SPACE=5'
3.D.STRUCTURE W/O BASEMENT/CRAWL SPACE=5'
3.E.PROPERTY LINE, PIPE OR LINED IRRIGATION DITCH=10'
3.F.INTERMITTENT IRRIGATION LATERAL, INFILTRATION STRUCTURE=10'
3.G.LAKE WATER COURSE, IRRIGATION DITCH, STREAM OR WETLAND=50'
3.H.DRY GULCH, CUT BANK OR FILL AREA=10'
3.I.STA TRENCH/BED, UNLINED SAND FILTER OR SEEPAGE PIT=5'
FLOW
Scale: N.T.S.
SITE & SOILS EVALUATION
SYSTEM DESIGN & CONSTRUCTION NOTES:
1.ALL CONSTRUCTION SHALL BE IN ACCORDANCE WITH CDPHE REGULATION 43 ONSITE WASTEWATER TREATMENT SYSTEM (OWTS) REGULATION, MOST CURRENT
EDITION AND LOCAL AGENCY REQUIREMENTS WHICH MAY OR MAY NOT SPECIFICALLY BE NOTED ON THE DRAWINGS. THE CONTRACTOR SHALL BE RESPONSIBLE
FOR KNOWING AND CONFORMING TO SUCH SPECIFIC DETAILS AS ARE REFERRED TO IN THE ABOVE MENTIONED REGULATIONS. THIS DRAWING DOES NOT
CONSTITUTE AN OWTS PERMIT. A PERMIT MUST BE OBTAINED FROM APPROPRIATE LOCAL AGENCY. THE CONTRACTOR MUST CONTACT THE LOCAL AGENCY
HEALTH DEPARTMENT AND THE PROJECT ENGINEER FOR INSPECTIONS OF THE CONSTRUCTED SYSTEM BEFORE BACKFILL. A REQUEST FOR INSPECTION BY THE
PROJECT ENGINEER AND THE COUNTY ENVIRONMENTAL HEALTH OFFICER MUST BE MADE AT LEAST 72-HOURS PRIOR TO THE DESIRED TIME OF BACKFILLING.
2.DEMAND CALCULATIONS (SEC.43.6.A.2.h)
2.A.ONE (1) BARN/SHOP USING TREATMENT LEVEL 1 (TL1).
2.B.AVERAGE DAILY WASTEWATER FLOW (ADWF) AND ORGANIC LOAD RATE (BOD5):
2.B.1.ADWF:
2.B.1.1.BARN/SHOP BATHROOM = 35 gpd * 3 EMPLOYEES (FACT./PLATS EXCL. OF IND. WW PER EMPLOYEE-SHOWER PROV.) = 105 gpd
2.B.1.2.PERSONAL TRAVEL TRAILER DUMP = 50 gpd * 1 TRAILER = 50 gpd
2.B.1.3.HORSE WASH = 30 gpd * 7 HORSES = 210 gpd
2.B.1.4.TOTAL: 365 gpd
2.B.2.BOD5:
2.B.2.1.BARN/SHOP BATHROOM = 0.08 lbs/day * 3 EMPLOYEES = 0.24 lbs/day
2.B.2.2.PERSONAL TRAVEL TRAILER DUMP= 0.12lbs/day * 1 TRAILER = 0.12 lbs/day
2.B.2.3.HORSE WASH = 0.30lbs/day * 7 HORSES = 2.10 lbs/day
2.B.2.4.TOTAL: 2.46 lbs/day
BOD5 mg/L = BOD5*1,000,000 = 2.46 lbs/day*1,000,000 = 808.1 mg/L
ADWF*8.34 365 gpd*8.34
2.B.3.CBOD5 = BOD5 * 0.85 = 686.88 mg/L
3.SEPTIC TANK (SEC.43.9.B.2.a):
3.A.48-HOURS OF MINIMUM DETENTION TIME: ADWF * 48 hrs/24 hrs = 365 * 48 hrs/ 24 hrs = 730 GALLONS.
3.B.INSTALL A 1000 GALLON TWO-COMPARTMENT SEPTIC TANK WITH EFFLUENT FILTER IN THE OUTLET RISER.
3.C.THE TANK MAY BE SUBJECT TO BUOYANCY (SEE DETAIL).
4.ABSORPTION AREA CALCULATIONS:
4.A.THE ABSORPTION AREA SLOPES GENTLY.
4.B.LONG TERM ACCEPTANCE RATE (LTAR) FOR TREATMENT LEVEL 1 (TL1) OF 0.50 gpd/SF (SEE SITE & SOILS EVALUATION NOTES/DETAIL).
4.C.MINIMUM SOIL TREATMENT AREA, A:
A = ADWF = 365 = 730 S.F.
LTAR 0.50 gpd/S.F.
4.D.SIZE ADJUSTMENT FACTORS: GRAVITY BED = 1.2; CHAMBERS = 0.7 (TABLE 10-2 AND 10-3).
4.D.1.A,adj = 730 SF * 1.2* 0.7 = 614 SF
4.E.GRAVELLESS CHAMBER TRENCH SYSTEM:
4.E.1.INFILTRATOR QUICK4: 614 SF / 12 SF/UNIT = 52 UNITS. INSTALL 52 UNITS IN A 4x13 UNIT BED CONFIGURATION.
4.E.2.ADS ARC 36: 614 SF / 15 SF/UNIT = 41 UNITS. INSTALL 44 UNITS IN A 4x11 UNIT BED CONFIGURATION.
5.THIS SYSTEM IS SIZED FOR TYPICAL HOUSEHOLD WASTES ONLY. BACKWASH OR FLUSHING FLOWS FOR REVERSE OSMOSIS UNITS OR WATER SOFTENERS AND/OR
FILTERS SHOULD NOT BE INTRODUCED INTO THIS SYSTEM. BACKWASH AND FLUSHING FLOWS SHALL BE DISPOSED OF WITHIN A SEPARATE INFILTRATIVE SYSTEM
(SEE BELOW).
6.CLEAN OUTS ARE REQUIRED AT THE HOUSE AND AT ALL BENDS GREATER THAN 45° AND AT LEAST EVERY 100-FEET BETWEEN THE HOUSE AND THE SEPTIC TANK.
7.THE CONTRACTOR SHALL BE RESPONSIBLE FOR INSTALLING ALL WATER TIGHT COMPONENTS THROUGHOUT THE SYSTEM TO PREVENT INFILTRATION.
8.INSTALL RISERS AS NECESSARY TO BRING ALL ACCESS PORTS TO FINAL GRADE. PORTS SHALL BE MARKED IF CAPS ARE TO BE BURIED.
9.INSTALL 3-INCHES OF BLUEBOARD INSULATION, 3-FEET WIDE, OVER SEWER AND EFFLUENT PIPE WHEREVER DEPTH IS LESS THAN 3-FEET. UNDER NO
CIRCUMSTANCES SHALL COVER BE LESS THAN 2-FEET.
10.SITE PLAN INFORMATION FROM OTHERS. LOCATIONS OF ALL COMPONENTS MAY BE VARIED AS NECESSARY AS LONG AS ALL MINIMUM DISTANCES AND SLOPES
MEET THOSE REQUIRED.
Scale: N.T.S.
TWO-WAY CLEANOUT
Scale: N.T.S.
GRAVESLLESS CHAMBER ABSORPTION BED
BOTTOM TO BE LEVEL AND FLAT OVER ENTIRE AREA TO WITHIN
0.1'±. (TYP.). IF NECESSARY TO ACHIEVE THIS SURFACE, IMPORT
CONCRETE SAND TO USE AS LEVELING MATERIAL. REMOVE ANY
ENCOUNTERED BOULDERS AND BACKFILL WITH LOAMY SAND OR
SANDY GRAVELS. DO NOT USE COMPACTED MATERIALS.
4"Ø PERFORATED PVC PIPE.
EXTEND PIPE TO REST ON
BOTTOM OF THE BED
COVER WITH 6" OF TOPSOIL
AND REVEGETATE
12
"
M
I
N
.
,
24
"
M
A
X
.
GRAVELLESS CHAMBER SYSTEM:
INFILTRATOR QUICK 4, ADVANCED DRAINAGE
SYSTEMS BIODIFFUSER (STANDARD), OR
ENGINEER APPROVED EQUAL.
FILL OVER THE CHAMBERS
WITH UNCOMPACTED WELL
GRADED LOCAL SOILS.
4"Ø COUPLING (UNION). USE A
HOLE SAW TO CUT OUT CIRCLE
OFF THE CENTER OF THE UNIT
STANDARD INSPECTION PORT, TYP. (4"Ø PVC
SOLID PIPE CUT TO FIT. LOCATE PER PLAN
VIEW. ATTACH REMOVABLE CAP OR
THREADED CLEANOUT ASSEMBLY.CIRCULAR IRRIGATION-STYLE VALVE
BOX & COVER - LID COLOR PURPLE
OR GREEN - LABEL "SEWER"
GENERAL ABSORPTION AREA NOTES
1.INSTALL CHAMBER UNITS IN ACCORDANCE WITH
MANUFACTURER'S RECOMMENDATIONS.
2.ABSORPTION BEDS SHALL NOT EXCEED 12' WIDE BY
100-FEET IN LENGTH, SHALL PARALLEL THE
TOPOGRAPHY AND SHALL BE INSTALLED IN A
RECTANGULAR PATTERN WHENEVER POSSIBLE.
3.THE BOTTOM OF THE ABSORPTION BED SHALL BE
LEVEL AND THE BOTTOM AND SIDEWALLS MUST BE
RAKED TO REMOVE ANY SOIL SMEARS INCURRED
DURING THE EXCAVATION. FAILURE TO DO SO MAY
REQUIRE THE CONTRACTOR TO REPLACE THE
ABSORPTION FIELD AT HIS/HER OWN EXPENSE.
4.DRAINAGE SWALES ARE TO BE PROVIDED ABOVE
AND AROUND THE FIELD, AS NECESSARY, TO
PREVENT SURFACE RUNOFF FROM ENTERING
ABSORPTION AREA.
5.NO EXCAVATION OF THE ABSORPTION FIELD IS TO
BE DONE DURING WET WEATHER AND USE OF
RUBBER TIRE VEHICLES OVER THE ABSORPTION
AREA IS STRICTLY PROHIBITED.
6.UNSUITABLE MATERIAL EXISTING WITHIN THE FIELD
SHALL BE EXCAVATED AND BACKFILL SHALL
CONSIST OF IMPORTED LOAMY SAND OR SANDY
GRAVEL. THE ENGINEER SHALL BE CONTACTED IF
BEDROCK OR GROUNDWATER IS ENCOUNTERED IN
THE EXCAVATION.
7.TOPSOIL COVER MAY BE VARIED (1-FOOT MINIMUM,
2-FOOT MAXIMUM) TO ALLOW FOR LANDSCAPING.
8.WHEN MULTIPLE BEDS ARE USED, BEDS SHALL BE
SEPARATED BY 6-FEET MIN. OF UNDISTURBED
SOILS.
2.
7
'
BUOYANT FORCE:
FB= (LxWxH)x(62.4 pcf)
FB=(9.25x5x2.7)x(62.4 pcf)
FB=7793 lbs
STRUCTURE WEIGHT = 11535 lbs
11535 > 7793
THEREFORE NO ADDITION
CONCRETE BLOCKS ARE REQUIRED.
SOIL CALVING/
POTENTIAL SEASONAL GROUNDWATER
Highway
6