HomeMy WebLinkAboutOWTS Design129 CAINS LANE
CARBoNDALE, CO A1623
970.309.5259
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June 29,2021 Project No. C1632
Rigo Hernandez
rigo@rghinc.net
Onsite Wastewater Treatment System Design
4-Bedroom Residence
Lot 50, Westbank Mesa
TBD Huebinger Drive
Garfield County, Colorado
Rigo,
CBO lnc. has completed an onsite wastewater treatment system (OWTS) design for the subject
residence. The 3.94-acre property is located outside of Glenwood Springs, in an area where OWTSs are
necessary.
Legal Description: Section: 2 Township: 7 Range: 89 Subdivision: WESTBANK RANCH PUD #4 RESUB
Lot: 50 (3.94 AC)
Parcel lD: 2395-022-06-050
SITE CONDITIONS
The property is currently undeveloped. A 4-bedroom residence is proposed.
The residence will be served potable water from a community water system. The water line will enter the
property from the subdivision road. No OWTS component will come within 2S-feet of the water line.
A subdivision well is located near the northern property boundary. The well is located at least S0Jeet
from the proposed septic tank and at least 1OO-feet from the proposed soil treatment area (STA).
The proposed STA location has an approximate fifteen percent slope to the north. The proposed area is
vegetated with native grasses and sage.
There should be no traffic or staging of material over the future STA site to avoid compaction of soils
prior to construction of the STA.
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SUBSURFACE
The subsurface was investigated by Kumar and Associates. Their report dated May 11,2021 , Prqect2l-7-
260 is enclosed.
A sample of the soil was taken from Test Pit #1 at approximately 4 to 4.5-feet below grade. Results were 6%
gravel, 33% sand,45% silt, and 16% clay.
We are proposing sizing of the STA based on Soil Type 2A based on our interpretation of the Kumar and
Associates report. A long term acceptance rate (LTAR) of 0.5 gallons per square foot will be used
to design the OWTS.
DESIGN SPECIFICATIONS
Desiqn Calculations:
AverageDesignFlow=TSGPDx2people/bedroomx3Bedrooms+75GPO1att''Bedroom)=525GPD
LTAR = 0.5 GPD/SF
525 GPD / 0.5 GPD/SF x 1.0 (gravity trenches) x 0.7 (chambers) = 735 SF
The OWTS design is based on 4-bedrooms. An average daily wastewater flow of 525 GPD will be used.
A future shop may include a toilet and sink which will be auxiliary use to the main residence.
Forthe purposes of this OWTS design, Benchmark Elevation 100'has been identified as Finished Floor
The sewer line will exit the residence at approximately 9B'. CBO lnc. should be notified of any
discrepancies or problems with grade elevations of proposed components during installation of the
OWTS.
*Elevations are based upon standard OWTS installation practices. Component elevations may change during
installation due to site conditions.
The 4-inch diameter SDR-35 sewer line exiting the residence must have a double-sweep clean out and a
minimum 2o/o grade to the septic tank. At the time the future shop is constructed, a 4-inch diameter SDR-
35 sewer line must be installed with a double-sweep clean out and minimum 2o/o grade, connecting to the
sewer line serving the main house before the septic tank with a wye fitting.
The system installation must include a 1500-gallon, two-compartment poly lnfiltrator@ septic tank with an
effluent filter on the outlet tee. A concrete septic tank may be substituted, if desired. Risers must bring
the manhole lids to grade for access. lf more than one riser is added to the septic tank, an extension
handle must be installed on the effluent filter.
Effluent will gravity flow to a distribution box, and then to four gravelless chamber trenches. The
distribution box must be accessible from grade and must have flow equalizers, or similar product,
installed on each outlet pipe in the distribution box to assure equal flow to each trench.
OWTS Component Minimum Elevation
Primary Tank lnlet lnvert Approximate horizontal distance 12' I min.2% tall
to septic tank / min. 3" fall
Distribution Box Approximate horizontal distance 16' / min. 1% fall
to d-box / min. 2" fall
Infiltrative Surface Approximate horizontal distance 12' l min. 1% fall
to infiltrative surface / min. 1.5" to upper-most
trench
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Each trench will consist of 16 'Quick 4' Standard Plus lnfiltrator@ chambers for a total of 64 chambers
and 768 square feet of infiltrative area. There must be at least 4-feet of undisturbed soil between each
trench. lnspection ports must be installed at the beginning and end of each trench. Ports may be cut to
grade and placed in sprinkler boxes for access.
COMPONENT SPECIFICATIONS
The component manufacturers are typical of applications used by contractors and engineers in this area.
CBO Inc. must approve alternative components prior to installation of the OWTS. Requests must
be submitted, in writing, to our office for approval prior to installation. Component technical data
sheets are available upon request.
Construction must be according to Garfield County On-Site Wastewater Treatment System Regulations, the
OWTS Permit provided by Garfield County Building Department, and this design.
INSTALLATION CONTRACTOR
CBO lnc. expects that the installer be experienced and qualified to perform the scope of work outlined in this
design. The installer must review this design thoroughly and coordinate with our office in advance of
installation. Any additional conditions in this design or county permit must be completed and documented
prior to final approval of the OWTS installation. Communication between the installer and this office is
expected throughout the installation.
INSTALLAT¡ON OBSERVATIONS
CBO lnc. must view the OWTS during construction. The OWTS observation should be performed before
backfill, after placement of OWTS components. Septic tanks, distribution devices, pumps, dosing
siphons, and other plumbing, as applicable, must also be observed. CBO lnc. should be notified 48 hours
in advance to observe the installation.
ln an effort to improve the accuracy of the record drawing, we request that the installer provide a
sketch of the installation, including path of the sewer lines, water line installation (if applicable),
septic tank location, STA location, and measurements from building corners or another fixed
objects on the property. This sketch is most easily provided on Sheet W2.0 of the OWTS Design
Packet. Photographs of the installation and final cover are also requested to supplement our installation
documentation.
COMPONENT MANUFACTURER I/IODEL NO IcoMMENTS
Septic Tank lnfiltrator@ M-1530-2CP 11 S00-gallon, 2-compartment
loolv seotic tank
Biotube Effluent Filter Orenco@ IF
lr'
ull Size Effluent Filter and
ousino
Tank Risers and Lids Orenco@ lDou
lrio'
ble-walled PVC Risers and
(24" diameter)
Distribution Box PolyLok loistribution box, flow
lequalizers, risers, lid
Chambers lnfiltrator@ Standard Plus 164'Quick 4' Standard Plus
lchambers
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REVEGETATION REQU IREMENTS
An adequate layer of good quality topsoil capable of supporting revegetation shall be placed over the entire
disturbed area of the OWTS installation. A mixture of native grass seed that has good soil stabilizing
characteristics (but without taproots), provides a maximum transpiration rate, and competes well with
successional species. No trees or shrubs, or any vegetation requiring regular irrigation shall be placed over
the STA. Until vegetation is reestablished, erosion and sediment control measures shall be implemented
and maintained on site. The owner of the OWTS shall be responsible for maintaining proper vegetation
cover'
opERATIoN TNF.RMAT''N AND MATNTENAN.E
The property owner shall be responsible for the operation and maintenance of each OWTS servicing the
property. The property owner is responsible for maintaining service contracts for manufactured units,
alternating STAs, and any other components needing maintenance.
Geo-fabrics or plastics should not be used over the STA. No heavy equipment, machinery, or materials
should be placed on the backfilled STA. Machines with tracks (not wheels) should be used during
construction of the STA for better weight distribution. Livestock should not graze on the STA. Plumbing
fixtures should be checked to ensure that no additional water is being discharged to OWTS. For example, a
running toilet or leaky faucet can discharge hundreds of gallons of water a day and harm a STA.
lf an effluent fllter or screen has been installed in the OWTS, we recommend this filter or screen be cleaned
annually, or as needed. lf the OWTS consists of a pressurized pump system, we recommend the laterals be
flushed annually, or as needed.
The homeowner should pump the septic tank every two years, or as needed gauged by measurement of
solids in the tank. Garbage disposal use should be minimized, and non-biodegradable materials should not
be placed into the OWTS. Grease should not be placed in household drains. Loading from a water softener
should not be discharged into the OWTS. No hazardous wastes should be directed into the OWTS.
Mechanical room drains should not discharge into the OWTS. The OWTS is engineered for domestic waste
only.
ADDITIONAL GONSTRUCTION NOTES
lf design includes a pump, weep holes must be installed to allow pump lines to drain to minimize risk of
freezing. The pump shall have an audible and visual alarm notification in the event of excessively high
water conditions and shall be connected to a control breaker separate from the high water alarm breaker
and from any other control system circuits. The pump system shall have a switch so the pump can be
manually operated.
Excavation equipment must not drive in excavation of the STA due to the potential to compact soil
Extensions should be placed on all septic tank components to allow access to them from existing grade
Backfill over the STA must be uniform and granular with no material greater than minus 3-inch.
LIMITS:
The design is based on information submitted. lf soil conditions encountered are different from conditions
described in report, CBO lnc. should be notified. All OWTS construction must be according to the county
regulations. Requirements not specified in this report must follow applicable county regulations. The
contractor should have documented and demonstrated knowledge of the requirements and regulations of
the county in which they are working. Licensing of Systems Contractors may be required by county
regulation.
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Please call with questions.
Sincerely,
CBO lnc.
Carla Ostberg, MPH, REHS
(ø.n[,* txfunE
rcrt lfumar & Assoclates, lnc.'
Geotechnical and Materials Engineers
and Environmental Scientists
An Employcc Owncd Compony
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email : kaglenwood@kumarusa.com
www.kumarusa. com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
SUBSOIL STUDY
FOR FOUNDATION DESIGN
PROPOSED RESIDENCE
LOT 5oo WESTBANK MESA
HUEBINGER DRIVE
GARFIELD COUNTY, COLORADO
PROJECT NO.21-7-260
MAY lt,2o2l
PREPARED FOR:
RIGO HERNANDEZ
1140 HOME AVENUE
sILTo COLORADO 81652
rieo@rghinc.net
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY ........
PROPOSED CONSTRUCTION ....
SITE CONDITIONS.
FIELD EXPLORATION...
SUBSURFACE CONDITIONS
FOUNDATION BEARING CONDITIONS
DESIGN RECOMMENDATIONS ...............
FOUNDATIONS
FOUNDATION AND RETAINING WALLS
FLOOR SLABS
UNDERDRAIN SYSTEM ...........
SITE GRADING.......
SURFACE DRAINAGE...............
LIMITATIONS
FIGURE 1 - LOCATION OF EXPLORATORY BORINGS AND PITS
FIGURE 2 - LOGS OF EXPLORATORY BORINGS AND PITS
FIGURE 3 - LEGEND AND NOTES
FIGURE 4 - SV/ELL-CONSOLIDATION TEST RESULTS
FIGURE 5 - GRADATION TEST RESULTS
FIGURE 6 - USDA GRADATION TEST RESULTS
TABLE 1- SUMMARY OF LABORATORY TEST RESULTS
TABLE 2- SUMMARY OF USDA LABORATORY TEST RESULTS
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Kumar & Associates, lnc. @ Project No. 21-7.260
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsoil study for a proposed residence to be located on
Lot 50, Westbank Mesa, Huebinger Drive, Garfield County, Colorado. The project site is shown
on Figure 1. The purpose of the study was to develop recommendations for foundation design.
The study was conducted in accordance with our proposal for geotechnical engineering services
to Rigo Hemandez, datedDecember 3,2020.
A field exploration program consisting of exploratory borings and pits was conducted to obtain
information on the subsurface conditions. Samples of the subsoils obtained during the field
exploration were tested in the laboratory to determine their classification, compressibility or
swell and other engineering characteristics. The results of the field exploration and laboratory
testing were analyzedto develop recommendations for foundation types, depths and allowable
pressures for the proposed building foundation. This report summarizes the data obtained during
this study and presents our conclusions, recommendations and other geotechnical engineering
considerations based on the proposed construction and the subsurface conditions encountered.
PROPOSED CONSTRUCTION
At the time of our study, design plans for the residence had not been developed. The building is
proposed in the area of the exploratory boring locations shown on Figure 1. V/e assume the
house will be one to two stories over a crawlspace or walkout basement excavation and will have
a maximum cut depth of one level, about 10 feet below the existing ground surface. For the
purpose of our analysis, foundation loadings for the structure were assumed to be relatively light
and typical of the proposed type of construction.
If building loadings, location or grading plans are significantly different from those described
above, we should be notified to re-evaluate the recommendations contained in this report.
SITE CONDITIONS
The site was vacant atthe time of our held work. The proposed building area slopes down to the
northeast at about 10 to 15 percent grade. Vegetation consists of sagebrush and scattered pinon
trees with an understory of grass and weeds. The buildin g area was accessed from the two-track
road that cuts through the property.
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FIELD EXPLORATION
The f,reld exploration for the project was conducted on March 25, Aprll l and April 20,2021.
Two exploratory borings were drilled at the locations shown on Figure 1 on March 25 and
April 1 to evaluate the subsurface conditions. The borings were advanced with 4 inch diameter
continuous flight auger powered by a truck-mounted CME-458 drill rig. The borings \ilere
logged by a representative of Kumar & Associates, Inc.
Samples of the subsoils were taken with l% inch and 2 inch I.D. spoon samplers. The samplers
were driven into the subsoils at various depths with blows from a 140 pound hammer falling 30
inches. This test is similar to the standard penetration test described by ASTM Method D-1586.
The penetration resistance values are an indication of the relative density or consistency of the
subsoils. Depths at which the samples \Ã/ere taken and the penetration resistance values are
shown on the exploratory boring logs, Figure2. The samples were returned to our laboratory for
review by the project engineer and testing.
Two exploratory pits were excavated in the proposed septic field area at the location shown on
Figure 1 on April 20 to evaluate subsurface conditions. The pits were dug with aYanmar
SV-120 mini excavator trackhoe. The pits were logged by a representative of Kumar &
Associates, Inc.
A sample of the subsoils was taken with disturbed sampling methods. The depth at which the
sample was taken is shown on the Logs of Exploratory Pits, Figure 2. The sample was returned
to our laboratory for review by the project engineer and testing.
SUBSURFACE CONDITIONS
Graphic logs of the subsurface profiles encountered at the site are shown on Figure 2. Below
about 1 foot of organic topsoil, the subsoils consist of about 6 feet of stiff to very stiff, sandy
silty clay with scattered gravel. At a depth of about 7 feet in the borings, the subsoils became a
dense clayey sand and gravel mixture. The soils encountered in the borings are similar to the
soils encountered at other nearby lots. The clay portions of these soils can possess an expansion
potential when wetted.
Laboratory testing performed on samples obtained during the field exploration included natural
moisture content, density and grain size analyses. Swell-consolidation testing was performed on
Kumar & Associates, lnc. @ Project No. 21-7-260
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a relatively undisturbed drive sample of the shallow clay subsoils. The swell-consolidation test
results, presented on Figure 4, indicate low compressibility under relatively light surcharge
loading and a low to moderate expansion potential when wetted under a constant light surcharge.
Results of gradation analyses performed on the minus llz-inch fraction of the subsoils are
presented on Figure 5 . The laboratory testing is summari zed in Table 1 .
Two pits were excavated with a trackhoe in the proposed septic area, located west and downhill
of the building site. Below about 1 foot of topsoil, the soils consisted of medium stiff Loam. A
USDA gradation was performed and the results are shown on Figure 6. The soils exposed in the
pits should be suitable for a conventional septic system. A civil engineer should design the
septic disposal system.
No free water was encountered in the borings and pits at time of exploration. The subsoils were
slightly moist to moist.
FOUNDATION BEARING CONDITIONS
The shallow clay subsoils encountered at the site possess low to moderate expansion potential
when wetted. The expansion potential canprobably be mitigated by load concentration to reduce
or prevent swelling in the event of wetting below the foundation bearing level. Surface runoff,
landscape irrigation, and utility leakage are possible sources of water which could causs wetting.
Alternately, the expansion potential can be mitigated by subexcavation and extending the bearing
level down to the underlying granular soils or replacing the sub-excavated depth with imported,
compacted structural fill.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory borings and the nature of
the proposed construction, we recommend the residence be founded with spread footings placed
on undisturbed natural soils or compacted structural fill.
The design and construction criteria presented below should be observed for a spread footing
foundation system.
1) Footings placed on the undisturbed natural clay soils can be designed for an
allowable bearing pressure of 3,000 psf. The footings should also be designed for
Kumar & Associates, lnc. o Project No.2l-7-260
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a minimum dead load pressure of 800 psf. In order to satisff the minimum dead
load pressure under lightly loaded areas, it may be necessary to concentrate loads
by using a grade beam and pad system. Wall-on-grade construction is not
recommended at this site to achieve the minimum dead load. Footings placed on
the underlying granular soils or properly compacted structural full can be
designed for an allowable bearing pressure of 2,500 psf. The structural fill should
consist of imported 3/¿-inch road base compacted to at least 98o/o of the maximum
standard Proctor density at a moisture content near optimum.
Based on experience, we expect settlement or heave of footings designed and
constructed as discussed in this section will be up to about 1 inch. There could be
some additional movement if the bearing soils were to become wet.
The footings should have a minimum width of 16 inches for continuous footings
and24 inches for isolated pads.
Continuous foundation walls should be heavily reinforced top and bottom to span
local anomalies and limit the risk of differential movement. One method of
analysis is to design the foundation wall to span an unsupported length of at least
14 feet. Foundation walls acting as retaining structures should also be designed to
resist a lateral earth pressure as discussed in the "Foundation and Retaining
'Walls" section of this report.
Exterior footings and footings beneath unheated areas should be provided with
adequate soil cover above their bearing elevation for frost protection. Placement
of foundations at least 36 inches below the exterior grade is typically used in this
area.
Prior to the footing construction, any existing fill, topsoil and loose or disturbed
soils should be removed and the footing bearing level extended down to the
designated bearing soils. We should evaluate the exposed bearing soils for
expansion potential and the need for sub-excavation and replacement with
compacted structural fill.
A representative of the geotechnical engineer should observe all footing
excavations prior to concrete placement to evaluate bearing conditions.
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4)
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FOUNDATION AND RETAINING WALLS
Foundation walls and retaining structures which are laterally supported and can be expected to
undergo only a slight amount of deflection should be designed for a lateral earth pressure
computed on the basis of an equivalent fluid unit weight of at least 55 pcf for backfill consisting
of the on-site fine-grained soils and at least 45 pcf for backfill consisting of imported granular
materials. Cantilevered retaining structures which are separate from the residence and can be
expected to deflect sufficiently to mobilize the full active earth pressure condition should be
designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of
at least 45 pcf for backfill consisting of the on-site fine-grained soils and at least 35 pcf for
backfill consisting of imported granular materials.
All foundation and retaining structures should be designed for appropriate hydrostatic and
surcharge pressures such as adjacent footings, traffrc, construction materials and equipment. The
pressures recommended above assume drained conditions behind the walls and a horizontal
backf,rll surface. The buildup of water behind a wall or an upward sloping backfill surface will
increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain
should be provided to prevent hydrostatic pressure buildup behind walls.
Backfill should be placed in uniform lifts and compacted to at least 90o/o of the maximum
standard Proctor density at a moisture content slightly above optimum. Backfill in pavement
areas should be compacted to at least 95o/o of the maximum standard Proctor density. Care
should be taken not to overcompact the backfill or use large equipment near the wall since this
could cause excessive lateral pressure on the wall. Some settlement of deep foundation wall
backfill should be expected even if the material is placed correctly and could result in distress to
facilities constructed on the backfill.
We recommend imported granular soils for backfilling foundation walls and retaining structures
because their use results in lower lateral earth pressures. Granular materials should be placed
within 2 feet of the ground surface and to a minimum of 3 feet beyond the walls. The granular
backfill behind foundation and retaining walls should extend to an envelope defined as a line
sloped up from the base of the wall at an angle of at least 30 degrees from the vertical. The
upper 2 feet of the wall backfill should be a relatively impervious on-site soil (or a pavement
structure should be provided) to prevent surface water infiltration into the backfill.
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The lateral resistance of foundation or retaining wall footings will be a combination of the
sliding resistance of the footing on the foundation materials and passive earth pressure against
the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated
based on a coefficient of friction of 0.30. Passive pressure of compacted backfill against the
sides of the footings can be calculated using an equivalent fluid unit weight of 325 pcf. The
coefficient of friction and passive pressure values recommended above assume ultimate soil
strength. Suitable factors of safety should be included in the design to limit the strain which will
occur at the ultimate strength, particularly in the case of passive resistance. Fill placed against
the sides of the footings to resist lateral loads should be compacted to at least 95o/o of the
maximum standard Proctor density at a moisture content near optimum.
FLOOR SLABS
The on-site clay soils possess an expansion potential and slab heave could occur if the subgrade
soils were to become wet. Slab-on-grade construction may be used provided precautions are
taken to limit potential movement and the risk of distress to the building is accepted by the
owner. A positive way to reduce the risk of slab movement, which is commonly used in the
area, is to construct structurally supported floors over crawlspace. We should evaluate the slab
subgrade conditions for expansion potential and the need for sub-excavation and replacement
with imported granular structural fill.
To reduce the effects of some differential movement, nonstructural floor slabs should be
separated from all bearing walls and columns with expansion joints which allow unrestrained
vertical movement. Interior non-bearing partitions resting on floor slabs should be provided with
a slip joint at the bottom of the wall so that, if the slab moves, the movement cannot be
transmitted to the upper structure. This detail is also important for wallboards, stairways and
door frames. Slip joints which will allow at least ll/r-inches of vertical movement are
recommended. Floor slab control joints should be used to reduce damage due to shrinkage
cracking. Slab reinforcement and control joints should be established by the designer based on
experience and the intended slab use.
A minimum 4 inch layer of free-draining gravel should be placed immediately beneath basement
level slabs-on-grade. This material should consist of minus 2-inch aggregate with less than 50o/o
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passing the No. 4 sieve and less than2Yo passing the No. 200 sieve. The free-draining gravel
will aid in drainage below the slabs and should be connected to the perimeter underdrain system.
Required fill beneath slabs can consist of a suitable imported granular material, excluding topsoil
and oversized rocks. The fill should be spread in thin horizontal lifts, adjusted to at or above
optimum moisture content, and compacted to at least 95Yo of the maximum standard Proctor
density. All vegetation, topsoil and loose or disturbed soil should be removed prior to fill
placement.
The above recommendations will not prevent slab heave if the expansive soils underlying slabs-
on-grade become wet. However, the recommendations will reduce the effects if slab heave
occurs. All plumbing lines should be pressure tested before backfilling to help reduce the
potential for wetting.
TINDERDRAIN SYSTEM
Although groundwater was not encountered during our exploration, it has been our experience in
mountainous areas and where clay soils are present, that local perched groundwater can develop
during times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can
also create a perched condition. Therefore, we recommend below-grade construction, such as
crawlspace and basement areas, be protected from wetting by att underdrain system. The drain
should also act to prevent buildup of hydrostatic pressures behind foundation walls.
The underdrain system should consist of a drainpipe surrounded by free-draining granular
material placed at the bottom of the wall backfill. The drain lines should be placed at each level
of excavation and at least 1 foot below lowest adjacent finish grade, and sloped at a minimum
lo/o grade to a suitable gravity outlet. Free-draining granular material used in the drain system
should consist of minus 2-inch aggregate with less than 50o/o passing the No. 4 sieve and less
than2Yo passing the No. 200 sieve. The drain gravel should be at least TYrfeet deep. Void form
below the foundation can act as a conduit for water flow. An impervious liner such as 20 mil
PVC should be placed below the drain gravel in a trough shape and attached to the foundation
wall above the void form with mastic to keep drain water from flowing beneath the wall and to
other areas of the building.
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SITE GRADING
The risk of construction-induced slope instability at the site appears low provided the building is
located as planned, and cut and f,rll depths are limited. We assume the cut depth for the basement
level will not exceed one level, about 8 to 10 feet. Embankment fills should be compacted to at
least 95%o of the maximum standard Proctor density near optimum moisture content. Prior to fill
placement, the subgrade should be carefully prepared by removing all vegetation and topsoil and
compacting to at least 95o/o of the maximum standard Proctor density. The fill should be
benched into the portions of the hillside exceeding 20%o grade. Permanent unretained cut and fill
slopes should be graded at2horizontal to 1 vertical or flatter and protected against erosion by
revegetation or other means. This office should review site grading plans for the project prior to
construction.
SURFACE DRAINAGE
The following drainage precautions should be observed during consttuction and maintained at all
times after the residence has been completed:
1) Excessive wetting or drying of the foundation excavations and underslab areas
should be avoided during construction. Drying could increase the expansion
potential of the soils.
2) Exterior backfill should be adjusted to near optimum moisture and compacted to
at least 95Yo of the maximum standard Proctor density in pavement areas and to at
least90o/o of the maximum standard Proctor density in landscape areas. Free-
draining wall backfill should be covered with f,rlter fabric and capped with about
2 to 3 feet of the on-site soils to reduce surface water infiltration.
3) The ground surface surrounding the exterior of the building should be sloped to
drain away from the foundation in all directions. We recommend a minimum
slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of
3 inches in the first 10 feet in paved areas.
4) Roof downspouts and drains should discharge well beyond the limits of all
backfill.
5) Landscaping which requires regular heavy irrigation should be located at least
5 feet from foundation walls. Consideration should be given to use of xeriscape
to reduce the potential for wetting of soils below the building caused by irrigation.
Kumar & Associates, lnc. @ Project No. 21-7-260
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LIMITATIONS
This study has been conducted in accordance with generally accepted geotechnical engineering
principles and practices in this arca atthis time. We make no warranty either express or implied.
The conclusions and recommendations submitted in this report are based upon the data obtained
from the exploratory borings drilled and pits excavated at the locations indicated on Figure 1, the
proposed type of construction and our experience in the area. Our services do not include
determining the presence, prevention or possibility of mold or other biological contaminants
(MOBC) developing in the future. If the client is concerned about MOBC, then a professional in
this special field of practice should be consulted. Our findings include interpolation and
extrapolation of the subsurface conditions identified at the exploratory borings and pits and
variations in the subsurface conditions may not become evident until excavation is performed. If
conditions encountered during construction appear to be different from those described in this
report, we should be notified at once so re-evaluation of the recommendations may be made.
This report has been prepared for the exclusive use by our client for design purposes. We are not
responsible for technical interpretations by others of our information. As the project evolves, we
should provide continued consultation and field services during construction to review and
monitor the implementation of our recommendations, and to veriff that the recommendations
have been appropriately interpreted. Significant design changes may require additional analysis
or modifications of the recommendations presented herein. 'We recommend on-site obsewation
of excavations and foundation bearing strata and testing of structural fill by a representative of
the geotechnical engineer.
Respectfully Submitted,
Kumar & Associates,
Daniel E. Hardin, P.
Reviewed by:
Steven L. Pawlak, P.E
DEFVkac
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Kumar & Associates, lnc. c Project No. 21.7.260
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I
BOR¡NG 1
EL.=84.5'
BORING 2
EL.=91.0'
PROFILE PIT 1 PROFILE PIT 2
0 0
22/12
1 4/12
WC=9.5
DD= 1 02
WC=7.3
GRAVEL=6-l sr¡to=s¡*r SILT=45
CLAY= 1 6
5 13/ 12
WC=8.5
DD= 1 06
-200=82
5
t-
LJ
t¡JtL
IT
t--
o_
L¡lo
35/ 12
WC=3.6
DD=1 1 9
-200=35 t-
t¡J
t¡J
LL
ITFo-
Lilo
10 10
30/ 12 34/12
WC=3.1
*4=18
-2OO=43
WC=2.6
*4=27
-200=34
15 1536/12 21
45
/6
/6
20 20
48/ 12 24/6
so/3
WC=2.0
+4=37
-2OO=27
25 25
81/11
50 30
63/ 12
zÉ 35
21 -7 -260 Kumar & Associates LOGS OF EXPLORATORY BORINGS AND PITS Fig. 2
!
E
I
LEGEND
TOPSOIL; ORGANIC SANDY SILTY CLAY, FIRM, MOIST, DARK BROWN
CLAY (CL); SILTY, SANDY, SCATTERED GRAVEL, STIFF TO VERY STIFF, SLIGHTLY MOIST,
BROWN.
cLAy AND S|LT (CL-ML); SANDy, MEDTUM ST|FF, SLTGHTLY Mo|ST T0 MO|ST, BROWN, LOAM
SAND AND GRAVEL (SM_GM); CLAYEY, DENSE, SLIGHTLY MOIST, REDDISH BROWN
DRIVE SAMPLE, 2_INCH I.D. CALIFORNIA LINER SAMPLE.
i
l
DRtvE sAMpLE, 1 s/B-rNcH r.D. spLtr spooN STANDARD pENETRATToN TEST
DISTURBED BULK SAMPLE
22/12 DRIVE SAMPLE BLOW COUNT. INDICATES THAT 22 BLOWS OF A 14o-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE THE SAMPLER 12 INCHES.
NOTES
1 THE EXPLORATORY BORINGS WERE DRILLED ON MARCH 25 AND APRIL 1 , 2021 WITH A 4_INCH
DIAMETER CONTINUOUS_FLIGHT POWER AUGER. THE EXPLORATORY PITS WERE EXCAVATED WITH
A MINI EXCAVATOR ON APRIL 20, 2021.
2, THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY PACING
FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED. THE LOCATIONS OF THE EXPLORATORY
PITS WERE MEASURED APPROXIMATELY BY TAPING FROM FEATURES SHOWN ON THE SITE PLAN
PROVIDED.
5. THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE MEASURED BY INSTRUMENT LEVEL
BASED ON THE BENCHMARK SHOWN ON FIG.I.
4. THE EXPLORATORY BORING AND PIT LOCATIONS AND ELEVATIONS SHOULD BE CONSIDERED
ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED.
5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING AND PIT LOGS
REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS
MAY BE GRADUAL.
6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORINGS AND PITS AT THE TIME OF DRILLING
OR DIGGING.
7. LABORATORY TEST RESULTS:
WC = WATER CONTENT (%) (ASTM D2216);
DD = DRY DENSITY (pcf) (ASTM D2216);
+4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (¡STU POSIS);
_2OO= PERCENTAGE PASSING NO.2OO SIEVE (ASTM DllAO);
GRAVEL= PERCENTAGE RETAINED 0N N0. 1 0 SIEVE;
SAND= PERCENTAGE PASSING NO.10 SIEVE AND RETAINED 0N NO.325 SIEVE;
SILT= PERCENTAGE PASSING NO. 525 SIEVE TO PARTICLE SIZE .002MM;
CLAY= PERCENT SMALLER THAN PARTICLE SIZE .002MM.
21 -7 -260 Kumar & Associates LTGTND AND NOTES Fig.5
I
4
3
2
ñ
JJ
UJ
=(/)
I
z.o
t-
o
-lo
U)z.oO
0
-1
2
3
-4
APPLIED PRESSURE - KSF f0
SAMPLE OF: Silty Cloy
FROM:Boringl@-4'
WC = 9.5 %, DD = 102 pcf
EXPANSION UNDER CONSTANT
PRESSURE UPON WETTING
21 -7 -260 Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig.4
100
90
80
70
60
50
40
30
20
fo
o
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINGS
24 HRS 7 HRS
U.S. STANDARD SERIÊS CLEAR SQUARE OPENINGS
\/A" \/a" I 1/t"
I
I
I
I
i
I
I
I
I
i
I
I
I
0
t0
50
40
50
60
70
80
90
loo
.
.425 2.O 152
DIAMETER OF PARTICLES IN MILLIMETERS
CLAY TO SILT COBBLES
GRAVEL 1A % SAND
LIQUID LIMIT
SAMPLE OF: Grovelly Sond ond Cloy
39%
PLASTICITY INDEX
SILT AND CLAY 43 %
FROM: Boring 1 @ 10' ond 15' (combined)
too
90
ao
70
60
50
40
30
20
10
0
o
10
20
50
10
50
60
70
80
100
=
.oo5 .o09 .019 .o37 .o75 150
DIAMETER O P SINMI S
CLAY TO SILT COBBLES
GRAVEL 37 % SAND
LIQUID LIMIT
SAMPLE OF: Cloyey Sond ond Grovel
56%
PLASTICITY INDEX
SILT AND CLAY 27 %
FROM: Boring 1 @ 20' ond 25'
(comblned)
Th€sô l6sl resulls opply only lo lh6
sompl€s which were lesled. The
lesllng reporl shqll nol b€ r€producad,
€xc€pl ln full, wllhoul lh€ wrllt€n
opprovol of Kumqr & Associot€s, lnc.
Slsve onolysls lesl¡ng ls polormed ln
occordonc€ wlth ASTM 06913, ASTM 07928,
ASTM C156 ond/or ASTM Dl140.
SAND GRAVEL
FIN E MEDIUM COARSE FIN E COARSE
HYDROMETER ANALYSIS SIEVE ANÂLYSIS
U.S. STANDARD SER¡ES CLEAR SOUÄRE OPENINGS
24 HRS 7 HRS
i MIN T'
lIME REÄDINGS
6ôMIN I9MIN
l
I
I
GRAVELSAND
FIN E MEDTUM ICOARSE FIN E COARSE
Kumar & Associates GRADATION TEST RESULTS Fig.521 -7 -260
I
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIN/E READINGS U,S, STANDARD
#140 #60 #35
RIES SOUARE OPENINGS
24 HR, 7 HR 1MIN,
#325 #18 #10 #4 11 3" 5',6', 8"
100
'10 90
20 80
30 70
o
l¡Jz.
FtJ
É.
l-z.tJO
É.tJ
o_
40 60
()z
tl,
tn
o-
Fz.t¡lO
É.
L¡Jù
50
60 40
70 30
80 20
90 10
100 0.001 .002 .005 .009 .019 .045 .106 .025 .500 1.00 2.00 4.75 9.5 19.0 37.5 76.2 152 203
DIAMETER OF PARTICLES IN MILLIN4ETERS
CLAY COBBLES
GRAVEL 6 %SAND 33 o/"SILT 45 %CLAY 16 %
USDA SOIL TYPE: Loam FROM: Profile Pit 1 @ 4-4.5'
I
/
/
/
V FINE FINE SN¡ALL N¡EDIUN,4 LARGE
SAND
À,lEDIUIuSILT
21 -7 -260 Kumar & Associates USDA GRADATION TEST RESULTS Fig.6
rc i;#*,ffiix:ffirniå'*"TABLE 1SUMMARY OF LABORATORY TEST RESULTSNo.2l-7-260Clayey Sand and GravelSandy Silty ClayClayey Sand and GravelSOIL TYPESandy Clayt.90006,Clayey SandGravelly Sand and Clay(%lEXPANSION(psflEXPANSIONPRESSURE("/rlPLASTICINDEXATTERBERG LIMITS(%)LIQUID LIMITPERCENTPASSING NO.200 stEVE3543278234SAND(%)393639GRADATION(%)GRAVEL81JI27r02t19106locflNAÏURALDRYDENSITYMINATURALMOISTURECONTENT9.53.61aJ2.08.32,6(ft)DEPTH4l10&1s20&25510&1s2SAMPLE LOCATIONBORING1
rc iiçli',ffifffin'"'È"ü'**TABLE 2SUMMARY OF USDA LABORATORY TEST RESULTSSOIL TYPELoam6I6USDA SOIL TEXTURESANDSILT(%)tf/"|JJ45GRADATIONGRAVELt%)SILT&CLAYV"lGRAVET(:/")CLAYt%)SAND(%)NATURALDRYDENSITY(pcr)NATURALMOISTURECONTENTtf/"\I --)4-4y,DEPTH(ft)SAMPLE LOCATIONPROFILEPIT1No.21-7-260
GD qPub¡lc.net* Garfield County, CO
Physical
Address
Owner
Address
1491HUEBINGER DR
GLENWOODSPRINGS
HERNANDEZ,ANAIS &
RIGOBERTO
1140 HOMEAVENUE
srLTco 81ó52
81ó01
2019Total Actual
Value
Overview
Legend
! Parcels
Roads
Parcel/Account
Numbers
Highways
: LimitedAccess
- Highway
' ' Major Road
Local Road
'' Minor Road
Other Road
Ramp
^* Ferry
Pedestrian Way
Owner Name
I i Lakes&Rivers
- County Boundary
Line
$125,000 Last2Sales
Date Price
3/12/2027 $175,000
9/t4/2jt6 $112,500
Account R100143
Number
Parcel 239502206050
Number
Acres 4
Land SqFt 0
TaxArea 010
2019 Mill Levy 75.5390
Date qeated:7/2/2O2I
Last Data Uploaded:7 /2/2021 77:37:23 AM
Deve roned bv¡!r) 9="üpgdçl
7t2t2021 qPublic.net - Garfield County, CO - Property Record Card: R100143
Ç qPublic.lt€t'" Garfi eld County, CO
Summary
Account
Parcel
Property
Address
Legal
Description
Acres
Land SqFt
Tax Area
Mill Levy
Subdivision
R100143
239502206050
1491 HUEBINGER DR, GLENWOOD SPRINGS, CO 81ó01
Section: 2 Township:7 Range: 89 Subdivision: WESTBANK RANCH
PUD #4 RESUB Lot: 50 (3.94 AC)
3.94
0
10
75.5390
WESTBANK RANCH PUD #4 RESUB
V:su¿.M¡p
Owner
HERNANDEZ, ANAIS & RIGOBERTO
1140 HOME AVENUE
srLT co 81ó52
Land
UnitType VACANT RES LOTS-0100 (VACANT LAND)
Squâre Feet 0
ActualValues
Assessed Year
Land Actual
lmprovement Actual
Totâl Actuâl
Assessed Values
Assessed Year
Land Assessed
lmprovement Assessed
Total Assessed
Tax History
Tåx Yeâr
Taxes Billed
2020
$2,409.68
Click here to view the tax ìnformation for this pglgg]-q!¡g-Qal¡lll@yJrc3:g¡ç-t5lryeþgjle.
Transfers
2027
$12s,000.00
$o.oo
$125,000.00
2027
$3ó,2s0.00
$o.oo
$3ó,2s0.00
2079
$2,437.72
Grântor
HERNANDEZ, VICTOR; HERNNDEZ,
ROSALBA
SUTER, ROBERT SUTER, ANNA
20r8 2077
$7,754.s2 $7,677.72
Grantee
HERNANDEZ, ANAIS: HERNANDEZ,
RIGOBERTO
HERNANDEZ, VICTOR; HERNANDEZ,
ROSALBA
SUTER, ROBERT & ANNA
WESTBANK MESA LIMITED PARTNERSHIP
2020
$110,000.00
$o.oo
$110,000.00
2020
$31,900.00
$o.oo
$31,900.00
2079
$110,000.00
$o.oo
$110,000.00
2019
$31,900.00
$o.oo
$31,900.00
Sale Date Deed Type
3/ T2/202T SPECIAL WARRANTY
DEED
9/14/2076 WARRANWDEED
6/6/7997 WARRANTYDEED
5/72/7994 Plat
3/7O/I994 WARRANTY DEED
Reception
Number
952272
509372
463059
460239
Book -
Page
TO2I
0750
Sale
Príce
$17s,000
$772,500
$82,500 WESTBANK MESA LIMITED
PARTNERSHIP
$o
$75O,OOO WESTBANK RANCH NO l LTD0895-
00ó5
Photos
https://qpublic.schneidercorp.com/Application.aspx?ApplD= 1 038&LayerlD=22381&PageTypelD=4&PagelD=9447&KeyValue=R100143 1t2
7t2t2021 qPublic.net - Garfield County, CO - Property Record Card: R100143
No data available for the following modules: Buildings, Sketches.
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