HomeMy WebLinkAboutOWTS Design-Submitted 02.16.2024GnnTIELD COUNTY OWTS RrpoRr
306 CouNrY Rono 340
PnnncHUTE, CoLoRADo
rT:'
September 2021
Prepared by
SsGM
11"8 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1,004
970.945.5948 fax
306 County Road 340 September 2021
306 CouNrY Rono 340
PnnncHUTE, Colonnoo
"l hereby affirm that this report for the Onsite Wastewater Treatment System (OWTS) for 306
County Road 340, 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 Land Use and 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"'
,Y.*^*,(' rt**a
License Nu
Licensed Professional Engineer, State of Colorado (Affix Seal)
PnrpRnro BY:
TeRnY BeNorrtt, P.E.
SGM Prole ct # 2018-27 1 .002
2
0
09t08t2021
OWTS Engineering Report
306 County Road 340
TnaLT OF CONTENTS
1.0 lntroduction
2.0 Preliminary lnvestigation
2.1 Property lnformation
2.2 Public Health Agency Records
2.3 Topography
2.4 Soil Data
2.5 Location of Physical Features
2.6 Additionallnformation
2.7 Landscape Position
2.8 Natural and Gultural Features
2.9 Current and Historic Land Use
3.0 Detailed Soil lnvestigation
3.1 Visual Evaluation
3.2 Tactile Evaluation
4.0 Recommendations
September 2021
5
5
5
5
6
6
6
6
6
6
6
7
7
7
8
3OWTS Engineering Report
306 County Road 340
Appendix
Drawing 1
Drawing 2
NRCS Soils Map
NRCS Absorption Field Soils Data
TP-1 Trench Photo
TP-1 Trench Photo
TP-2 Trench Photo
TP-2 Trench Photo
SGM Soil Observation Logs
SGM SoilTexture by Feel
September 2021
4OWTS Engineering Report
306 County Road 340 September 2021
l.0lntroduction
A new 3-bedroom residential structure is being proposed for construction on the subject property. To
treat wastewater from the residence, an onsite wastewater treatment system (OWTS) will be installed.
This report describes the results of a preliminary investigation, reconnaissance, and detailed soil
evaluation to support design of the OWTS for the subject property, in addition to presenting design
of the system to be compliant with Garfield County's "On Site Wastewater Treatment System
Regulations", hereinafter referred to as Reg43.
SGM personnel contributing to this report are:
Terry Bendetti - PE/CPOW Certified Competent Technician/NAwT Certified Designera
2.0 Preliminary lnvestigation
2.1 Property lnformation
Phvsical Address: 306 County Road 340, Parachute, Colorado
Leqal Description: Section 3 Township:7 Range: 95; Subdivision Morrisania Ranch. Account No.
R27 0100, Parcel 2407 0340001 0.
Existinq Structures: An existing residential structure, shop and outbuilding are presently located
on the subject property. According to County documents the following information for the home
was obtained.
o Building permit issued in April of 1980.
o The home has 1,370 square feet of floor areao The home has two bedrooms.. The home has one story.. A sunroom was added in July of 1982.
Domestic Water: Provided by a well in the southeast portion of the subject property. The well is
located greater than the minimum setback requirement of 100 feet, Table 7-1 of Reg43.
2.2 Public Health Agency Records
Search of Garfield County's Public Records found there is an existing ISDS permit for this
residence. The permit indicates the size of the septic tank is 1,000 gallons and the absorption
area has 330 square feet.
The existing system is functioning. No issues of concern have been expressed by the Owner of
the subject property.
Since the subject property has multiple OWTSS, it needs to be established whether the systems
are considered as one or as separate systems. According to WQSA-6 (Water Quality Site
Application Policy), multiple systems are considered separate if the horizontal influence area
(HlA) of each system does not overlap and each system has a daily capacity less than or equal
to 2,000 gpd.
The HIA associated with the existing system is 56 feet, for the proposed system 74 teet. There is
no overlap of the HIA calculated for each system. ln addition, each system has a daily wastewater
5OWTS Engineering Report
306 County Road 340 September 2021
capacity less than 2,000 gpd; 300 gpd for the existing system and 450 gpd for the proposed
system. Therefore, these systems are separate systems. The HIA for each system is shown on
sheet 1.
2.3 Topography
Topography in the vicinity of the OWTS slopes from south to the north at grades of between 4.5
to 8.0 percent. Grades in the easVwest direction are flat and continuous, not broken by
irregularities in the ground surface.
2.4 Soil Data
According to the Web Soil Survey for the Natural Resources Conservation Service (NRCS), soils
associated with this subject property are classified as map unit 56, Potts loam. Potts loam has
grades of between 6 lo 12 percent, which agrees with field observation.
Pots loam also has a very limited rating for septic tank absorption fields due to the slow movement
of water. However, plotting of percentages of clay, sand and silt given for this soil unit on the
USDA Textural Triangle indicates the soils would classify as soil type 2 or 2A. Soils having a
classification type of 2 or 2A are very suitable for absorption fields, having long term application
rates (LTAR) of 0.6 and 0.5 gallons per day per square foot of area (gpd/ft2), respectively.
2.5 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.
Potable
Water
Structure with
Basement, Crawl
Space, Footing Drains
Property Lines, Piped
lrrigation
Septic
Tank
Septic Tank 50 5 10
Effluent Line 50 N/A 10
STA 100 20 10 5
2.6 Additional lnformation
a. Easements: There is a 12.0' easement at the west side of the property for Garfield County
Road 340.
b. Floodplain Maps: According to FEMA (Federal Emergency Management Agency), there is
no flood mapping for the area where the OWTS will be located.
2.7 Landscape Position
The landscape position for the STA is considered summit and will not be impacted by stormwater
drainage. The slope shape is linear - linear (LL) towards the northwest property corner.
2.8 Natural and Cultural Features
No natural or cultural features were identified in the site reconnaissance.
2.9 Gurrent and Historic Land Use
6OWTS Engineering Report
306 County Road 340 September 2021
The subject property is in Garfield County's Rural zone district, which is for Agricultural and other
uses. Current and historic land use has been agricultural, its future use is expected to also be
agricultural.
3.0 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 May 18,2021. Visual evaluation of two soil profile test pits were
conducted in the field and samples collected from each test pit. The samples were taken to SGM's
Office to classify the soil type that will receive the effiuent waste using the soil texture by feel method.
Test pits were excavated adjacent to the proposed location for the STA, see sheet 1 for locations.
Visual evaluation of both test pits was conducted under adequate light conditions, with the soil being
in an unfrozen state.
3.1 Visual Evaluation
The Client excavated two soil profile test pits, TP-1 and TP-2, with SGM personnel being on site.
Both test pits were excavated to an approximate depth of 6 feet, with no groundwater nor bedrock
being encountered.
Both test pits exhibited topsoil with a root zone for the first 8 to 10 inches. One layer horizon from
the bottom of the topsoil zone to the bottom of each pit was observed. Rocks were not
encountered in either test pit.
Excavation was terminated at a depth of 6 feet for the following reasons:
o A limiting layer was not encountered.r The in-situ soils to treat effluent will begin at 2 feet from the surface, which with the 4 feet
of required vertical separation between the infiltrative surface and a limiting layer can be
met.
Soil observation logs and photos can be found in the Appendix.
All measurements are from ground surface.
3.2 Tactile Evaluation
SGM conducted a Soil Texture by Feel test on the soil samples collected from each test pit per
CPOW's methodology.
Gravels were not present in either sample, therefore Table 10-1, Section 43.10 of Reg43 was
used to determine soiltype and applicable LTAR.
7OWTS Engineering Report
306 County Road 340 September 2021
Results of the soil texture by feel tests are shown in the following table.
*Weak < 1 inch; Moderate 1-2 inches; Strong > 2 inches
Results shown in the above table indicate a USDA soil classification of Silty Clay, soil type 4 or
4A'.
To determine the proper soil type, 4 or 4A, the USDA soil structure type and grade were used
The following Table shows the soil's USDA structure type and grade determined for each sample
SAMPLE
USDA Soil
Structure
Tvpe
USDA Soil
Structure
Grade
TP-1 Blocky Moderate
TP-2 Blockv Moderate
According to Table 10-1, section43.10 of Reg43, both soil types 4 and 4,A can have a blocky
structure type, but only soil type 4 can have a moderate soil structure grade. As such, the soil
to receive the effluent waste is classified as soil type 4, having a LTAR of 0.20 gpd/ft2 for
treatment level 1 (TL1).
The USDA soil classification based on NRCS data for clay, sand and silt percentages in
subsection 2.4 above does not support this conclusion. However, the NRCS data for absorption
fields does agree with the soil test by feel results.
SGM's worksheets for the Soil Observation Logs, Soil Texture by Feel and STA LTAR by Soil
Texture, Soil Structure and Treatment Level can be found in the Appendix.
4.0 Recommendations
An OWTS as a wastewater treatment system is suitable for this site. At a minimum The OWTS shall
have:
. A septic tank.o A trench type STA.. Category 3 distribution media in the STA.. A distribution box.. 4" diameter distribution laterals.o 4" diameter service lines.
Effluent from the residence will be conveyed through service lines, by gravity, to a new septic tank.
From the septic tank the effluent will be conveyed through service lines to a distribution box, effluent
flow will be by gravity. The distribution box will divide the effluent flow into equal volumes for each
distribution lateral. Each lateral will convey its volume of effluent to its associated STA trench, effluent
flow will be by gravity.
8
SAMPLE
Depth from
Ground
Surface (ft)
Does Soil
Form a Ball
(yes/no)
Does Soil
Form a
Ribbon
(ves/no)
*Type of Ribbon
Formed (Weak,
Moderate,
Stronq)
How Does the Soil Feel
(G ritty/Smooth/Neither)
TP-1 4.0 Yes Yes Stronq Verv Smooth
TP-2 4.0 Yes Yes Strono Verv Smooth
OWTS Engineering Report
306 County Road 340 September 2021
The proposed residence will be a 3-bedroom single family residence. Per Table 6-1 of the County's
owTS Regulations the design flow rate will be 450 gpd (gallons per day).
# Bedrooms Occupancy (# of
Persons)
Wastewater Flow per
Person Design Flow (gpd)
3 6 75 450
The site of the proposed STA for the OWTS will be north of the proposed residence. The septic tank
will be installed in ine vicinity shown on sheet 1. The proposed residence is expected to have a crawl
space, basement, a foundation drain or a combination thereof. To comply with setback requirements
siated in Table 7-1 of Reg43, the Owner will need to construct the proposed residence at least 20
feet from where the STA is located. The OWTS STA site elevation is approximately 5,941 feet above
sea level (NAVD 88).
Sewer Pipe: Sewer service pipe shall be 4-inch SDR-35 PVC pipe installed with a minimum grade
of lo/o, maximum grade of 8o/o. Joints shall be solvent welded. Cleanouts are required:
1) Within 5 feet of the existing building'
2) At spacing not to exceed 50 feet'
3) Upstope of two or more bends closer than 10 feet'
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 2.
Septic Tanks: One new 1,500 gallon septic tank with two bays is recommended for the possibility for
futgre e-pansion. The tank must be on the Colorado Department of Public Health and Environment's
accepted'septic tank list. 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.
The effluent filter handle shall extend to within twelve inches of the lid'
The septic tank shall:
1) Be located down gradient of the home.
2) Have a covering of no more than 4-feet in depth.
3) Be at a location accessible for pumping and maintenance.
The installer must coordinate with the Owner as to the elevation of the tank's inlet invert stub out for
connection to the service line from the residence. A septic tank having a thicker cover than 4-feet will
not be allowed.
Distribution Box: The distribution box shall be centered as shown on sheet 1 in a manner to distribute
ef1,rent equally to the trenches. The Engineer should be contacted if alignments or locations change
in order to verify regulation requirements are maintained. The box, as shown, should be capable of
one inlet pipe traving an insertion point a minimum of 1-inch above outlet openings and 6 outlet
openings.
Soil Treatment Area: The soil treatment area is sized using criteria found in section 43.10 of Reg43
tor a g+eOroom reiidential home, using trenches for the soil treatment area, effluent application by
gravity and chambers for the distribution media. The following table summarizes sizing of the STA.
9OWTS Engineering RePort
No.
Bedrooms
Daily
Design
Flow (spd)
LTAR
Method of
Application
Adiustment Factor
Distribution Media
Adjustment
Factor
STA
Size
(sf)
No, Chambers
(12sflchamber)
3 450 0.2 1.0 0.7 1,575 131
306 County Road 340 September 2021
The STA shall be excavated as field conditions require using the following guidelines
1. Six trenches, 5 having 22infiltrators and t having 21 infiltrators.
2. Trenches shall be no wider than 3-feet.
3. Trench lengths shall be no greater than 88-feet.
4. A minimum of 4-feet, measured sidewall to sidewall, shall separate trenches.
5. The infiltrative surface shall be no greater than 3-feet from the surface.
6. Trench floors shall be level.
7. Chambers shall be placed per the manufacturer's directions.
Chambers shall have a minimum of 10.8 square footage area per regulation requirement 43.13
The STA configuration shown on sheet 1 may be modified or changed in the field as long as guidelines
2, 4, 5,6 and 7 are maintained and setbacks in section 2.5 can be met. Other setbacks per Table 7-
1 of Reg43 may be required, so review of Table 7-1 should be completed prior to relocating the STA.
ln addition, the Engineer should be consulted prior to relocating the STA.
The STA shall have a final soil cover as described on sheet 2. This may mean that the STA cover
will need to be 16-inches +/- when initially placed to allow for settlement over the freeze-thaw of a
winter season. The surface of the STA shall be seeded after installation of the system. A native,
upland seed mix should be used. These mixes do not require irrigation and develop a growth 10 to
15 inches high. 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 its performance.
OWTS Engineering Report 10
306 County Road 340 September 2021
Appendix
Sheet 1
Sheet 2
NRGS Soils Map
NRCS Absorption Field Soils Data
TP-l Trench Photo
TP-1 Trench Photo
TP-z Trench Photo
TP-2 Trench Photo
SGM Soil Observation Logs
SGM Soil Texture bY Feel
OWTS Engineering RePort 11
:
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Jablonsky OWTS
306 County Road 340,
Parachute, Colorado
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NRCS Soils Map
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Soil Matr-Rifle Area, Colorado, Parts of Garfield and Mesa Counties
(309 CountY Road 340)
2437cn
24l6m 2€m 241800
2/41m
390 27 5l N
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lYap flojection: Web Mercator Comercoordinates: WGS84 Edge tics: UTM Zone 13N
1m
WGS84
USDA
-
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil SurveY
7t1212021
Page '1 of 3
390 27 23' N
243900 2441m
390 27'23'N
USDA
-
Natural Resources
Conservation Service
Soil Map-Rifle Area, Colorado, P. of Garfield and Mesa Counties
(309 County Road 340)
Web Soil Survey
National Cooperative Soil Survey
7t12t2021
Page 2 of 3
MAP LEGEND MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24.0O0.
Warning: 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.
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 projection 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
Survey Area Data: Version 13, Jun 5, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Dec 31, 2009-Oct
12,2017
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Area of lnterest (AOl)g1 Spoil Area
$ Stony Spot
|s VeryStonySpot
W Wetspot
& Other
*- Special Line Features
Water Features
Streams and Canals
Transportation
Rails
d lnterstate Highways
* UsRoutes
. .)t:: Major Roads
Local Roads
Background
I Aerial Photography
Area of lnterest (AOl)
Soils
E Soil Map Unit Polygons
t j Soil Map Unit Lines
I Soil Map Unit Points
Special Point Features
(gt Blowout
Hl Borrow Pit
X Clay Spot
* Closed Depression
K Gravel Pit
".. cravelly Spot
(} Landfill
S, Lava Flow
* Marsh or swamp
# Mine or Quarry
S Miscellaneous Water
g Perennial Water
Ed Rock Outcrop
+ Saline Spot
:{ SandySpot
€F Severely Eroded Spot
S Sinkhole
h Slide or Slip
@ sodic spot
Soil Map-Rifle Area, Colorado, Parts of Garfield and Mesa Counties 309 County Road 340
Map Unit Legend
Percent of AOIAcree in AOIMap Unlt NameMap Unit Symbol
21 .5o/o17.2lldefonso stony loam, 25lo 45
percent slopes
34
78.5o/o62.7Potts loam, 6 to 12 Percent
slopes
56
100.0%79.9Totals for Area of lnterest
USDA
=
Natural Resources
Conservation Service
Web Soil SurveY
National Cooperative Soil SurveY
711212021
Page 3 of 3
NRCS Absorption Field Soils Data
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Septic Tank Absorption Fields-Rifle Area, Colorado, Parts of Garfield and Mesa Counties
(309 County Road 340)
243800 24/m
24.3fm 2437rfi 243800
390 27 52" N
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7t12t2021
Page 1 of 5
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Natural Resources
Conservation Service
8@
Web Soil Survey
National Cooperative Soil Survey
Map Scale: 1 :4,250 if printed on A portrait (8.5" x 1 1") shed.
MeErs
0501m200m
=L
i8
N
A m 400
Map projection: Web Mercator Comercoodinates: WGS84 Edgetics: UTM Zone 13N WGS84
1m
USDA
-
390 2723'N
243m 2M
390 27 23'N
USDA
-
Natural Resources
Conservation Service
Septic Tank Absorption Fields-Rifle Area, C. . ado, Parts of Garfield and Mesa Counties
(309 County Road 340)
Web Soil Survey
National Cooperative Soil Survey
7t12t2021
Page 2 of 5
MAP LEGEND MAP INFORMATION
Area of lnterest (AOl)Background
I Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.Area of lnterest (AOl)
Soils
Soil Rating Polygons
I Verylimited
n Somewhat limited
t Notlimited
f| Not rated or not available
Soil Rating Lines
t+ Very limited
) u Somewhat limited
N Notlimited
) t Not rated or not available
Soil Rating Points
I Very limited
tr Somewhat limited
I Not limited
tr Not rated or not available
Water Features
N Streams and Canals
Transportation
ffi Rails
te lnterstate Highways
* USRoutes
::-i.- Major Roads
: Local Roads
Warning: 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.
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 projection 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
Survey Area Data: Version 13, Jun 5, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Dec 31, 2009-Oct
12,2017
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Septic Tank Absorption Fields-Rifle Area, Colorado, Parts of Garfield and Mesa Counties 309 County Road 340
Septic Tank AbsorPtion Fields
Percent of AOIRating reasons
(numeric
values)
Acres in AOIComponent
name (percent)
RatingMap unit
symbol
Map unit name
Slope (1.00)21 .SYo
Large stones
(1.00)
17.2lldefonso (90%)Very limitedlldefonso stony
loam, 25 to 45
percent slopes
34
Slow water
movement
(1.00)
78.5o/o
Slope (0.04)
62.7Pons (85%)Very limited56Potts loam, 6 to
12 percent
slopes
100.0olo79.9Totals for Area of lnterest
Percent of AOIAcres in AOIRating
100.0%79.9Very limited
100.0o/o79.9Totals for Area of Interest
Natural Resources
Conservation Service
Web Soil SurveY
National Cooperative Soil SurveY
711212021
Page 3 of 5USDA
=
Septic Tank Absorption Fields-Rifle Area, Colorado, Parts of Garfield and Mesa Counties 309 County Road 340
Description
Septic tank absorption fields are areas in which effluent from a septic tank is
distributed 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. "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.
USDA
-
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7t12t2021
Page 4 of 5
Septic Tank Absorption Fields-Rifle Area, Colorado, Parts of Garfield and Mesa Counties 309 County Road 340
Rating Options
Aggregation Method: Dominant Condition
Aggregation is the process by which a set of component attribute values is
reduced to a single value that represents the map unit as a whole.
A map unit is typically composed of one or more "components"' A component is
either some type of soil or some nonsoil entity, e.9., rock outcrop. For the
attribute being aggregated, the first step of the aggregation process is to derive
one attribute value for each of a map unit's components. From this set of
component attributes, the next step of the aggregation process derives a single
value that represents the map unit as a whole. Once a single value for each map
unit is derived, a thematic map for soil map units can be rendered. Aggregation
must be done because, on any soil map, map units are delineated but
components are not.
For each of a map unit's components, a corresponding percent composition is
recorded. A percent composition of 60 indicates that the corresponding
component typically makes up approximately 60% of the map unit. Percent
composition is a critical factor in some, but not all, aggregation methods.
The aggregation method "Dominant Condition" first groups like attribute values
for the components in a map unit. For each group, percent composition is set to
the sum of the percent composition of all components participating in that group.
These groups now represent "conditions" rather than components. The attribute
value alsociated with the group with the highest cumulative percent composition
is returned. lf more than one group shares the highest cumulative percent
composition, the corresponding "tie-break" rule determines which value should
be returned. The "tie-break" rule indicates whether the lower or higher group
value should be returned in the case of a percent composition tie. The result
returned by this aggregation method represents the dominant condition
throughout the map unit only when no tie has occurred.
Component Percent Cutoff: None Specified
Components whose percent composition is below the cutoff value will not be
considered. lf no cutoff value is specified, all components in the database will be
considered. The data for some contrasting soils of minor extent may not be in the
database, and therefore are not considered'
Tie-break Rule; Higher
The tie-break rule indicates which value should be selected from a set of multiple
candidate values, or which value should be selected in the event of a percent
composition tie.
Natural Resources
Conservation Service
Web Soil SurveY
National Cooperative Soil SurveY
7t1212021
Page 5 of 5USDA
-
TP-1 Trench Photos
TP-2 Trench Photos
SGM Soil Observation Logs
SSGM Soll Prollle To$t Plt Graphic Log Number::t:- r
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Comments:
{Sknrruc}lucancrf) lDalcl
Certitled Ststenrenu I hereby cenity thEt I h.rre completed thig
work ln accordance with all applirable ordintnca, ruler and laws.
SGM Soil Texture by Feel
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Soil Texture by Feel Does the soil remain in a ballwhen squeezed?
Place soil in palm of hand. Add water drop'wise
and knead the soilinto a smooth and plastic
No
consistency, like moist
putty.
Add dry soil
Yes
the soiltoo wet?
No
Place ballof soil between thumb and forefinger,
gently pushing the soil between with the thumb,
squeezing it upward into a ribbon. Form a ribbon
of uniform thickness and width. Allow
ribbon to emerge and extend
over the forefinger,
breaking from
its own
weight.
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c
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3
2
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nk veriafion crcaled by D Harison, M 8rowr, W Brown, R lawr.
Add water
ls the soil too dry?
Yes
No
the soil form a ribbon?
No
Does soil feel very gritty? Yes
No
Does soilfeelvery smooth? Yes
Nc
Nelther gritty nor smooth? Yes
Forms a1-2"
ribbon before
breaking
ffi
a
2" of
longer
brea
Forms a weak
ribbon less
than l"before
breaking
loam
Soil Type 2 ot 2A
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loam
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pStux: fc3 Bijll$rlt i .800,*8$-61::'
SALTDA I DURANGO I GUNNISON | 6RAND JUNCTION I M:EKER
Place soil in palm of hand, Add water drop-wise
and knead the soil into a smooth and plastic
Eased on U50A l{R(S Gulde t0Terture by fe€l - 5, J. lhien, 1979, modif€d.
lhii varlalhr oeated by D llanison, M 8rom, W 3rown, R lawi,
TP.2
Soil Texture by Feel Does the soil remain in a ballwhen squeezed?
No
consistency, like moist
putty.
Add dry soil
Yes
s the soil too wet?
No
Place ballof soil between thumb and foreftnger,
gently pushing the soil between with the thumb
squeezing it upward into a ribbon. Form a ribbon
of uniform thickness and width. Allow
ribbon to emerge and extend
over the forefinger,
breaking fiom
its own
weight.
c
.s
G
3
2
Add water
ls the soil too dry?
Yes
No
the soilform a ribbon?
Does soil feel very gritty? Yes
No
Does soilfeelvery smooth? Yes
No
Nelther gritty nor smooth? Yes
Forms a weak
ribbon less
than 1"before
breaking
Loam
Soil Type 2 ot 2A
Srn yloam
Silt lorn
lorm
Forms a1-2"
ribbon before
breaking
sm
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longer
b
a
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0
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6LENWOOD SPRINGS I ASPEN I
DftUXl FOll 8{JSlrr-655 I -800"488-63?7
sALTDA I DURANGO I GUNNISON I GRAND JUNCTION I MEEKER
r.:. .-.,: ji:..r,:,tr:j
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GTLITHOMPSON
YEARS
FOUNDED IN 1971
CTL I THOMPSON
@
GEOTECHNICAL ENGINEERING INVESTIGATION
JABLONSKY RESIDENCE
306 COUNTY ROAD 340
GARFIELD COUNTY, COLORADO
Prepared For:
SGM, INC.
1 18 W. Sixth Street, Suite #200
Glenwood Springs, CO 81601
Attention : Jeff Simonson
Project No. GS06603.000-1 20
September 23,2021
(revised Septembe r 29, 2021)
J lrrrnJrrrrnIrrlrIIIIITI
ffi
TABLE OF CONTENTS
SCOPE
SUMMARY OF CONCLUSIONS ....
SITE CONDITIONS
PROPOSED CONSTRUCTION ...
GEOLOGY AND GEOLOGIC HAZARDS..
suBsuRFACE coND|T|oNS.........,.........
EARTHWORK.
Excavations
Subexcavation and Structural Fill....
Foundation Wall Backfi11..................
FOUNDATTON ................
SLAB.ON-GRADE CONSTRUCTION
CRAWL SPACE CONSTRUCTION..,.
FOUNDATION WALLS
SUBSURFACE DRAINAGE................
SURFACE DRAINAGE
CONCRETE
CONSTRUCTION OBSERVATIONS .
GEOTECHNICAL RISK
LIMITATIONS
FIGUREl-VICINITYMAP
FIGURE 2 - AERIAL PHOTOGRAPH
FIGURE 3 - SUMMARY LOGS OF EXPLORATORY PITS
FIGURES 4 AND 5 - FOUNDATION WALL DRAIN CONCEPTS
TABLE I - SUMMARY OF LABORATORY TESTING
sGM, rNC.
JABLONSKY RESIDENCE
PROJECT NO. GS06003.000-120 REVISED
1
1
2
3
3
3
5
5
5
6
6
I
I
0
0
1
2
3
3
4
....1
....1
,..' 1
....1
,...1
...,1
.,.. 1
ffi
SCOPE
CTL lThompson, lnc. (CTL) has completed a geotechnical engineering in-
vestigation for the Jablonsky Residence proposed at 306 County Road 340 in
Garfield County, Colorado. We conducted this investigation to evaluate subsur-
face conditions at the site and provide geotechnical engineering recommenda-
tions for the proposed construction. The scope of our investigation was set forth
in our Proposal No. GS 21-A218. Our report was prepared from data developed
from our field exploration, laboratory testing, engineering analysis, and our expe-
rience with similar conditions. This report includes a description of the subsurlace
conditions observed in our exploratory pits and provides geotechnical engineer-
ing recommendations for design and construction of the foundation, floor system,
below-grade walls, subsurface drainage, and details influenced by the subsoils. A
summary of our conclusions is below.
SUMMARY OF CONCLUSIONS
Subsoils encountered in our exploratory pits consisted of about 1
foot of sandy clay "topsoil" underlain by sandy clay and sandy silt
with scattered gravel and cobbles to the total excavated depth of
8.5 feet. Groundwater was not found in our exploratory pits at the
time of our subsurface investigation.
Geologic mapping and our engineering experience indicate the
soils at this site have the potential for significant consolidation when
wetted under building loads. We judge a footing foundation is ap-
propriate for the Jablonsky Residence, provided the soils are
subexcavated to a depth of 3 feet below planned footings and re-
placed as densely-compacted, structural fill.
Slab-on-grade floors are likely to be constructed in basement and
garage areas of the residence. To enhance potential floor slab per-
formance, we recommend subexcavation of the soils below floor
slabs to a depth of at least 2 feet and replacement as densely-com-
pacted, structural fill.
sGM, tNC.
JABLONSKY REIDENCE
PRoJECT NO. GS06603.000-120 REVISED
1
2
3
1
ffi
A foundation wall drain ehould be conetructed around the perimeter
of basement and crawl space areas to mitigate surface water that
infrlffirbacRflthsoits. Site grading should be designed and con-
structed to rapidly convey surface water away from the building.
SITE CONDITIONS
The Jablonsky Residence is proposed on Morissania Mesa at 306 County
Road 340 in Garfield County, Colorado. A vicinity map with the location of the
site is included as Figure 1. The property is an approximately 1O.7-acre parcel
northeast of the intersection of County Road 301 and County Road 340. Single-
family residences and out-buildings are on adjacent parcels to the north and
south. An aerial photograph of the site is shown on Figure 2. Ground surface at
the site generally slopes down to the north at grades visually estimated at less
than 5 percent. The site has historically been irrigated hayfield. A photograph of
the site at the time of our investigation is below.
Looking northeast across site.
sGM, lNC.
JASLONSKY REIDENCE
PRoJECT NO. GS06603.000-'120 REVISED
4
2
'
ffi
PROPOSED CONSTRUCTION
Architectural plans for the residence were not developed at the time of our
geotechnical engineering investigation. The residence is proposed as a two-level,
wood-frame structure with an attached garage. Basement and crawl space areas
are being considered. Floors in garage and basement areas would likely be
slabs-on-grade. We anticipate perimeter foundation loads between 1,000 and
2,000 pounds per linear feet and interior column loads of less than 75 kips. We
should be provided with architectural plans, as they are developed, so we can
provide geotechn ica l/geo-structu ral eng ineering input.
GEOLOGY AND GEOLOGIC HAZARDS
We reviewed the geologic map by the U.S. Geology Survey (USGS) titled,
"Geologic Map of the Rulison Quadrangle, Garfield County, Colorado", by Yeend,
Donnell, and Smith (dated 1988). The subject property is located in an area of
Morrisania Mesa that is mapped as alluvial-terrace and fan-gravel deposits of the
Pleistocene Epoch. These deposits are described as sandy gravel, poorly-sorted,
poorly-stratified rock fragments with a matrix of clay and silt. The soils found in
our exploratory pits are generally consistent with the geologic mapping. Due to
the depositional method, the soil deposits have not been subject to significant ge-
ologic loads. These soils are prone to consolidation when wetted under building
loads. We judge sandy clay and sandy silt have potential for moderate to high
amounts of consolidation when wetted under building loads.
SUBSURFACE CONDITIONS
Subsurface conditions for our geotechnical engineering investigation were
investigated by observing the excavation of two exploratory pits (TP-1 and TP-2)
at the site. The pits were excavated with a trackhoe at the approximate locations
sGM, rNC.
JABLONSKY REIDENCE
PROJECT NO. GS06603.000-120 REVISED
3
ffi
shown on Figure 2. Exploratory excavation operations were directed by our rep-
resentative, who logged subsurface conditions encountered in the pits and ob-
tained samples of the soils. Graphic logs of the soils found in our exploratory pits
are shown on Figure 3.
Subsoils encountered in our exploratory pits consisted of about 1 foot of
sandy clay "topsoil" underlain by sandy clay and sandy silt with scattered gravel
and cobbles to the total excavated depth of 8.5 feet. Groundwater was not found
in our exploratory pits at the time of our subsurface investigation. PVC pipe was
installed in our pits, prior to backfilling, to facilitate subsequent checks of ground-
water. A photograph of the subsoils encountered in our exploratory pits is below.
Subsurface conditions exposed in TP-1
Samples of the soils obtained from our exploratory pits were returned to
our laboratory for pertinent testing. Engineering index testing on two samples of
the soils indicated low plasticity with liquid limits of 39 percent and non-liquid (NL)
and plasticity indices of 17 percent and non-plastic (NP). These samples con-
tained 84 and 52 percent silt and clay size material (passing the No. 200 sieve),
Laboratory test results are summarized on Table l.
sGM, lNC,
JABLONSKY REIDENCE
PRoJECT NO. GS06503.000-1 20 REVISED
4
ffi
EARTHWORK
Excavations
Based on our subsurface investigation, excavations at the site can be ac-
complished with conventional, heavy-duty excavation equipment, such as a me-
dium-size trackhoe. Sides of excavations deeper than 5 feet must be sloped or
braced to meet local, state, and federal safety regulations. The sandy clay and
sandy silt soils will likely classify as Type B soils based on OSHA criteria. Sides
of excavations in Type B soils should be sloped no steeper than 1 to 1 (horizontal
to vertical). Contractors are responsible for site safety and providing and main-
taining safe and stable excavations. Contractors should identify the soils encoun-
tered and ensure that OSHA standards are met.
Free groundwater was not encountered in our exploratory pits at the time
of our subsurface investigation. We do not expect excavation for the proposed
construction will penetrate a free groundwater table. We suggest excavations be
sloped to a gravity discharge or to a temporary sump where water from precipita-
tion can be removed by pumping,
Subexcavation and Structural Fill
Geologic mapping and our engineering experience indicate the soils at
this site have the potential for significant consolidation when wetted under build-
ing loads. We judge a footing foundation is appropriate for the Jablonsky Resi-
dence, provided the soils are subexcavated to a depth of 3 feet below planned
footings and replaced as densely-compacted, structuralfill. We recommend a
subexcavation and replacement process of at least 2 feet below interior slab-on-
grade floors. A more uniform structural fill would result by subexcavating to the
same depth (e.9., 3 feet below footings) below the entire residence footprint. The
sGM, tNC.
JABLONSKY REIDENCE
PRoJECT NO. GS06603.000.120 REVISED
5
ffi
subexcavation process should extend at least 1 foot beyond the perimeter of the
residence footprint.
The excavated soils can be reused as structuralfill, provided they are free
of rocks larger than 4 inches, organics, and debris. Structural fill should be
placed in loose lifts of 8 inches thick or less, moisture-conditioned to within 2 per-
cent of optimum moisture content, and compacted to at least g8 percent of stand-
ard Proctor (ASTM D 698) maximum dry density. Moisture content and density of
structural fill should be checked by a representative of our firm during placement.
Observation of the placement and compaction process is necessary.
Foundation Wall Baqkfill
Proper placement and compaction of foundation wall backfill is important
to reduce infiltration of surface water and consolidation settlement of backfill
soils. This is especially important for backfill areas that will support concrete
slabs, such as driveways and patios. The excavated soils free of rocks larger
than 4 inches in diameter, organics, and debris can be reused as backfill adja-
cent to foundation wall exteriors.
Backfill should be placed in loose lifts of approximately 10 inches thick or
less, moisture-conditioned to within 2 percent of optimum moisture content, and
compacted to at least 95 percent of standard Proctor (ASTM D 698) maximum
dry density. Moisture content and density of the backfill should be checked during
placement by a representative of our firm.
FOUNDATION
The soils at this site have the potential for significant consolidation when
wetted under building loads. We judge a footing foundation is appropriate for the
sGM, lNC.
JABLONSKY REIDENCE
PROJECT NO, GS06603.000-120 REVTSED
6
ffi
Jablonsky Residence, provided the soils are subexcavated to a depth of 3 feet
below planned footings and replaced as densely-compacted, structural fill. The
structural fill should be in accordance with recommendations in the Subexcava-
tion and Structural Fill section.
Some amount of subsurface wetting is inherent after a building is con-
structed. The recommendations in the SUBSURFACE DRAINAGE and
SURFACE DRAINAGE sections will be critical to reduce the amount of subsur-
face wetting below the building and enhance the potential performance of foot-
ings.
Recommended design and construction criteria for footings are below.
These criteria were developed based on our analysis of field and laboratory data,
as well as our engineering experience.
The residence can be constructed on a footing foundation that is
supported by a 3-foot thickness of densely-compacted, structural
fill. The structural fill should be in accordance with the Subexcava-
tion and Structural Fill section.
Footings on the structural fill can be sized using a maximum net al-
lowable bearing pressure of 3,000 psf. The weight of backfill soil
above the footings can be neglected for bearing pressure calcula-
tion.
Continuous wall footings should have a minimum width of at least
16 inches. Foundations for isolated columns should have minimum
dimensions of 24 inches by 24 inches. Larger sizes may be re-
quired, depending upon foundation loads.
4.Grade beams and foundation walls should be well-reinforced to
span undisclosed loose or soft soil pockets. We recommend rein-
forcement sufficient to span an unsupported distance of at least 12
feet.
The soils under exterior footings should be protected from freezing.
We recommend the bottom of footings be constructed at a depth of
at least 36 inches below finished exterior grades. The Garfield
sGM, lNC.
JAELONSKY REIDENCE
PROJECT NO. GS06603.000-{20 REVTSED
1
2
3
5
7
ffi
County building department should be consulted regarding required
frost protection depth.
SLAB-ON-GRADE CONSTRUCTION
Slab-on-grade floors are likely to be constructed in basement and garage
areas of the residence. Exterior concrete flatwork is likely to be constructed adja-
cent to the building. To enhance potential performance of interior floor slabs, we
recommend subexcavation of the soils below floor slabs to a depth of at least 2
feet and replacement as densely-compacted, structuralfill. The structuralfill
should be in accordance with recommendations in the Subexcavation and Struc-
tural Fill section.
Based on our analysis of field and laboratory data, as well as our engineer-
ing experience, we recommend the following precautions for slab-on-grade con-
struction at this site.
Slabs should be separated from exterior walls and interior bearing
members with slip joints that allow free vertical movement of the
slabs,
The use of underslab plumbing should be minimized. Underslab
plumbing should be pressure tested for leaks before the slabs are
construCted. Plumbing and utilities which pass through slabs should
be isolated from the slabs with sleeves and provided with flexible
couplings to slab supported appliances'
Exterior concrete flatwork should be isolated from the building.
These slabs should be well-reinforced to function as independent
units. Movements of these slabs should not be transmitted to the
building.
Frequent controljoints should be provided, in accordance with
American Concrete lnstitute (ACl) recommendations, to reduce
problems associated with shrinkage and curling.
sGM, tNC.
JABLONSKY REIDENCE
PROJECT NO. GS06603.000-120 REVISED
1
2
3
4
I
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The lnternational Building Code (lBC) may require a vapor retarder
be placed between the base course or subgrade soils and the con-
crete slab-on-grade floors. The merits of installation of a vapor re-
tarder below floor slabs depend on the sensitivity of floor coverings
and building to moisture. A properly installed vapor retarder (10 mil
minimum) is more beneficial below concrete slab-on-grade floors
where floor coverings will be sensitive to moisture.
CRAWL SPACE CONSTRUCTION
Crawl spaces are contemplated below the main level floor in parts of the
residence. Where structurally-supported floors are installed over a crawlspace,
the required air space depends on the materials used to construct the floor.
Building codes normally require a clear space of at least 18 inches between un-
treated wood floor components of the structural floor and exposed earth on the
bottom of the crawl space. For non-organic systems, we recommend a minimum
clear space of 12 inches.
Utility connections, including water, gas, air duct, and exhaust stack con-
nections to appliances on structural floors should be capable of absorbing some
deflection of the floor, Plumbing that passes through the floor should ideally be
hung from the underside of the structural floor and not laid on the bottom of the
excavation. lt is prudent to maintain the minimum clear space below all plumbing
lines.
Control of humidity in crawl spaces is important for indoor air quality and
performance of wood floor systems. We believe the best current practices to con-
trol humidity involve the use of a vapor retarder or vapor barrier (10 mil minimum)
placed on the soils below accessible subfloor areas. The vapor retarder/barrier
should be sealed at joints and attached to concrete foundation elements. lt may
be appropriate to install a ventilation system that is controlled by humidistat.
sGM, rNC.
JABLONSKY REIDENCE
5
9
PROJECT NO. GS06603.000.t20 REVTSED
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FOUNDATION WALLS
Foundation walls which extend below-grade should be designed for lateral
earth pressures where backfill is not present to about the same extent on both
sides of the wall, such as in basements and crawl spaces. Many factors affect
the values of the design lateral earth pressure. These factors include, but are not
limited to, the type, compaction, slope, and drainage of the backfill, and the rigid-
ity of the wall against rotation and deflection.
For a very rigid wall where negligible or very little deflection will occur, an
"at-rest" lateral earth pressure should be used in design. For walls that can de-
flect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types),
design for a lower "active" lateral earth pressure may be appropriate. Our experi-
ence indicates typical below-grade walls in residences deflect or rotate slightly
under normal design loads, and that this deflection results in satisfactory wall
performance. Thus, the earth pressures on the walls will likely be between the
"active" and "at-rest" conditions.
For backfill soils conforming with recommendations in the Foundation Wall
Backfill section that are not saturated, we recommend design of below-grade
walls at this site using an equivalent fluid density of at least 45 pcf. This value as-
sumes deflection; some minor cracking of walls may occur. lf very little wall de-
flection is desired, a higher design value approaching the "at-rest" condition using
an equivalent fluid pressure of 60 pcf may be appropriate. These equivalent den-
sities do not include allowances for sloping backfill, surcharges or hydrostatic
pressures
SUBSURFACE DRAINAGE
Water from precipitation, snowmelt, and irrigation frequently flows through
relatively permeable backfill placed adjacent to a residence and collects on the
sGM, tNC.
JABLONSKY REIDENCE
PROJECT NO. GS06603.000-120 REVISED
10
ffi
surface of less permeable soils at the bottom of foundation excavations. This pro-
cess can cause wet or moist conditions in below-grade areas, such as base-
ments and crawl spaces, after construction. To reduce the likelihood water pres-
sure will develop outside foundation walls and the risk of wetting in below-grade
areas, we recommend provision of a foundation wall drain around the perimeter
of below-grade areas of the residence.
The foundation wall drain should consist of 4-inch diameter, slotted PVC
pipe encased in free-draining gravel. A prefabricated drainage composite should
be placed adjacent to foundation walls. Care should be taken during backfill op-
erations to prevent damage to drainage composites. The drain should discharge
via a positive gravity outlet or lead to a sump where water can be removed by
pumping. Foundation wall drain concepts are shown on Figures 4 and 5.
SURFACE DRAINAGE
Surface drainage is critical to the performance of foundations, floor slabs,
and concrete flatwork. Site grading should be designed to rapidly convey surface
water away from the residence. Proper surface drainage and irrigation practices
can help control the amount of surface water that penetrates to foundation levels
and contributes to settlement or heave of soils that support foundations, slabs,
and other structures. Positive drainage away from the foundation and avoidance
of irrigation near the foundation also help to avoid excessive wetting of backfill
soils, which can lead to increased backfill settlement and possibly to higher lal
eral earth pressures, due to increased weight and reduced strength of the back-
fill. We recommend the following precautions.
The ground surface surrounding the exterior of the residence
should be sloped to drain away from the building in all directions.
We recommend a minimum constructed slope of at least 12 inches
in the first 10 feet (10 percent) in landscaped areas around the resi-
dence.
1
SGM, INC.
JABLONSKY REIDENGE
PROJECT NO. GS06603.000-120 REVTSED
t1
ffi
Backfill around the foundation walls should be moisture-treated and
compacted pursuant to recommendations in the Foundation Wall
Backfill section.
We recommend the residence and existing building be provided
with roof gutters and downspouts. The downspouts should dis-
charge well beyond the limits of all backfill. Splash blocks and/or
extensions should be provided at all downspouts so water dis-
charges onto the ground beyond the backfill.
Landscaping should be carefully designed and maintained to mini-
mize irrigation.. Plants placed close to foundation walls should be
limited to those with low moisture requirements. lrrigated grass
should not be located within 5 feet of the foundation. Sprinklers
should not discharge within 5 feet of foundations. Plastic sheeting
should not be placed beneath landscaped areas adjacent to foun-
dation walls or grade beams. Geotextile fabric will inhibit weed
growth yet still allow natural evaporation to occur.
CONCRETE
Concrete in contact with soil can be subject to sulfate attack. Our experi-
ence in the area of the site indicates the soils contain low levels of water-soluble
sulfates. ACI 332-08, "Code Requirements for Residential Concrete", indicates
that any type of cement can be used for concrete in contact with the subsoils that
have low levels of sulfate concentration.
ln our experience, superficial damage may occur to the exposed surfaces
of highly-permeable concrete, even though sulfate levels are relatively low. To
control this risk and to resist freeze-thaw deterioration, the water-to-cementitious
materials ratio should not exceed 0.50 for concrete in contact with soils that are
likely to stay moist due to surface drainage or high-water tables. Concrete should
have a total air content of 6 percent +l- 1.5 percent. We recommend all founda-
tion walls and grade beams in contact with the subsoils be damp-proofed.
sGM, tNC.
JABLONSKY REIDENCE
PROJECT NO. G506603.000-120 REVISED
2
3.
4
12
ffi
CONSTRUCTION OBSERVATIONS
We recommend that CTL lThompson, lnc. be retained to provide con-
struction observation and materials testing services for the project. This would al-
low us the opportunity to verify whether soil conditions are consistent with those
found during this investigation. lf others perform these observations, they must
accept responsibility to judge whether the recommendations in this report remain
appropriate. lt is also beneficialto projects, from economic and practical stand-
points, when there is continuity between engineering consultation and the con-
struction on materials testing phases.
GEOTECHNICAL RISK
The concept of risk is an important aspect of any geotechnical evaluation.
The primary reason for this is that the analytical methods used to develop ge-
otechnical recommendations do not comprise an exact science. The analytical
tools which geotechnical engineers use are generally empirical and must be tem-
pered by engineering judgment and experience. Therefore, the solutions or rec-
ommendations presented in any geotechnical evaluation should not be consid-
ered risk-free and are not a guarantee that the interaction between the soils and
the proposed structure will lead to performance as desired or intended. The engi-
neering recommendations in the preceding sections constitute our estimate of
those measures necessary to help the building perform satisfactorily,
This report has been prepared for the exclusive use of the client for the
purpose of providing geotechnical design and construction criteria for the pro-
posed project. The information, conclusions, and recommendations presented
herein are based upon consideration of many factors including, but not limited to,
the type of structures proposed, the geologic setting, and the subsurface condi-
tions encountered. The conclusions and recommendations contained in the re-
port are not valid for use by others. Standards of practice continuously change in
sGM, lNc. 13JABLONSKY REIDENCE
PROJECT NO. GS06603.000-120 REVTSED
ffi
the area of geotechnical engineering. The recommendations provided in this re-
port are appropriate for three years. lf the proposed project is not constructed
within three years, we should be contacted to determine if we should update this
report.
LIMITATIONS
Our exploratory pits provide a reasonable characterization of subsurface
conditions below the site. Variations in the subsurface conditions not indicated by
the pits will occur. We should be provided with architectural plans, as they are
developed, so we can provide geotechnical/geo-structural engineering input.
This investigation was conducted in a manner consistent with that levelof
care and skill ordinarily exercised by geotechnical engineers currently practicing
under similar conditions in the locality of this project. No warranty, express or im-
plied, is made. lf we can be of further service in discussing the contents of this
report, please call.
cTL I THOMPSON, tNC.Reviewed
tu 2{7\
Ryan R. Barbone, E.l.T.
Project Engineer
RRB:JDK:abr
sGM, tNC.
JABLONSKY REIDENCE
PROJECT NO. GS06603.000.120 REVTSED
mes D,
sion Ma
I
I
14
ffi
0 1500 3000 NOTE:
SOALET t'- 3000'
sGM, tNC.
JABLONSI(Y FESIDENCE
SATELLITE IMAGE FROM GOOGLE EARTH
(DATED JUNE 17, 2016)
i
Vicinity
Map
PARACHI.'IE
PROJECT NO. GSO6603.OOO-1 20 Flg. 1
LEGEND:
TP_1 APPROXIMATE LOCATION OFI EXPLORATORY PIT
NOTES
ffi
0 50 100
SCALE: 1'= 100'
1) SATELLTTE lMAct FROM GOOGLE
rARTH (DATED JUNE 17, 2A16)
2) LOCATTONS 0F EXPLoRATORY P|TS
ARE APPROXIMATE
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sGM, tNC.
JABLONSIff RESIDENOE
3sl
1
ffi
::a .{3.
Aerial
Photograph
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13
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PROJECT NO. GSO6603.000-1 20 Flg. 2
TP-1
10
15
sGM, rNC.
JABLONSI(Y RESIDENCE
CTLIT PROJECT NO. GS06603.000-120
"TOPSOIL" CLAY, SILT, SANDY, MOIST.
BROWN.
CI.AY, SILT, SANDY. SCATTERED GRAVEL
AND COBBLES, SLIGHTLY MOIST, TAN. (CL,
ML, CL-ML)
INDICATES HAND DRIVE SAMPLE.
INDICATES BULK SAMPLE FROM EXCAVATED SOILS
ffi
Summary Logs of
Fi[g'"rat6ry
FIG- 3
TP-2
0 0 LEGEND
5 nF
IUul
lJ-
rFo-
IUo F
F
Ft!
IUtr
IFo-
UJo
10
15
NOTES:
1.
2
EXPLORATORY PITS WERE EXCAVATED W|TH A
TMCKHOE ON JULY 7. 2A21 . PITS WERE BACKFILLED
IMMEDIATELY AFTER EXPLORATORY EXCAVATION
OPEMTIONS WERE COMPLETED.
GROUNDWATERWAS NOT FOUND IN EXPLOMTORY
PITS AT THE TIME OF DRILLING EXCAVATION. PVC
PIPE WAS INSTALLED IN OUR PITS, PRIOR TO
BACKFILLING, TO FACILITATE SUBSEQUENT CHECKS
OF GROUNDWATER.
3. THESE LOGSARE SUBJECTTOTHEEXPLANATIONS,
LIMITATIONS AND CONCLUSIONS IN THIS REPORT.
tr
SLOPE
OSHA
PER k;-;
DRAJI{AGE
coMPosm
(MTRADRATN 6000
oR EquMArENr)
2-g'
SHEEIING
BELOTV-GMDE WATJ.
SUP JOINT
ATTACH PI.ASIIC
TO FOUNDATION
COVER ENNRE WDTH OF
GRAI/EL WIIH NON-TYOVEN
GEOTDMIE FABRIC (MIMR
l/0ON oR eOuVrueffi).
SGM,INC.
JABLONSKY RESIOENCE
PROJECT NO. GSO6603.OOO-1 20
Foundation
Wall Drain
Concept
8' MINIMUM
OR BBTOND
1:1 SLOPE FROM
BOTTOM OF FOOTING
(rTHtcHEvER tS GREAIER)
l:lNQtt DhMETER PERFORATE) RtctD DRATN ptpEfiE ptpE sHourD BE ptAcED m f rnnuCx-fmi
4 gpPq oF AT rEASr 1,/8-|NCH DROP PER
FOOT OF DRAIN.
qlqgE ptpE rN 1/2. TO 7-1/2. SCREENED
GRAvEL ExIEND GRAI/EL ureHru.Iv ro roonxc
Nl!!f AT IEASr 1/2 Hscfn oF FoonNc. Rtr-ENnRE TRENcH wim cnnva_-
NOTE:
TI{E-BOTTOM OF THE DRAIN SHOUI.D BE [
'{4qT
2 INCHES BELOIT BOTTOM OFryqTlNc _4r THE HtcHEsT,FotNT nno suiqg _@tilwniii-ro"a
- posiinc- b'cAW'OUIr-Er OR TO A SUMP TVHERE WETER CAN
'f'REiiiryEO'W"'PUMPING.
Fla- 4
tr
NOTE
P&{t_r! sfiour.D BE AT tEASr 2 NCHESpF=o.U_BgIroM oF FoonNc Ar iiit'-Ilcrysj potuT Ar.lD sLope oowx{,ifino
To_i. Eggll_rvE cnavrl omri-'itil' lii
l_qq1p_ wFtERE wersn cAiiTt
REMOIGD Br PUMPINC. - -' _-
MIMDRAIN GzOON
OR EQUMAI.^ENT
ATTACH PTASIIC
TO FOUNDATION
SHEEIING
wAttSLOPE
OSHA
SGM.INC.
JABI{,NSIff RESIOENCE
ProJect No. GSO66O3.OOO-1 20
fcRAttL SPASE JPER
FOOTINC OR PAD
VAPOR BARRIER
E, MINIMUM
OR BEYONDl:1 SLOPE FROM
9OTTOM OF FOOTTNG
(wHtcHEVER ts GRFATER)
krlrcll.lrftrErER pqEfqRATED DRATN ptpE. THEprp_E sHoutD ne pucED lilt; TREilioi 'i{riH'/i-
llolE.gf Ar LEAsr t,/s-tNcH onbF ien roorOF DMIN.
Foundation
Wall Drain
Concept
silRUCruMt FtooR
Flg.5
TABLE I
SUMMARY OF LABOMTORY TESTING
PROJECT NO. cS06603.000_1 20
ffi
DESCRIPTION
CLAY, SANDY (CL)
SILT SANDY
PASSING
NO.200
SIEVE
(o/o\
84
52
SOLUBLE
SULFATES
(o/ol
CITY
LIMIT INDEX
17
NP
39
NL
DRY
DENSITY
(PCF)
MOISTURE
CONTENT
(%\
DEPTH
(FEET)
7-8
7.5-8.5
I
EXPLORATORY
PIT
TP-1
TP-2