HomeMy WebLinkAboutEngineer's OWTS Installation Report 11.14.2018H-P�KUMAR
Geotechnical Engineering 1 Engineering Geology
Materials Testing I Environmental
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood@kumarusa.com
November 14, 2018
Jordan Architects
Attn: Brad Jordan
P. O. Box 1031
Glenwood Springs, Colorado 81602
bracijordanarchitect@gmail.com
grail.com
Office Locations: Parker, Glenwood Springs, and Silverthorne, Colorado
Project No. 18-7-170
Subject: As -Built Evaluation of Onsite Wastewater Treatment System, Proposed
Garage/Shop, Holmes Residence, 8984 County Road 117, Garfield County,
Colorado
Dear Brad:
As requested, we observed the onsite wastewater treatment system (OWTS) at the subject site on
several visits between August 20, 2015 and November 7, 2018. The purpose of our visits was to
determine construction of the system with respect to the design. This report presents our
findings and recommendations. The services were performed in general accordance with our
agreement for professional services to Jordan Architects dated February 19, 2018. H-P/Kumar
previously issued a partial As -Built observation letter of the system dated June 12, 2018.
Background Information: Hepworth-Pawlak Geotechnical (now H-P/Kumar) previously
prepared the design for the OWTS at the site as submitted in a report dated October 31, 2014,
Job No. 114 393A. The construction consists of a one-story garage/shop building with one
bedroom and one bathroom. The OWTS was designed to be pumped to a mounded sand soil
treatment area (STA). We understand that construction of the project was halted and that
changes in contractors occurred.
Site Observations: A partial As -Built observation of the OWTS system was performed by
Hepworth-Pawlak Geotechnical (H -P Geotech) on August 20, 2015, while the system was under
construction, with photographs taken of most system components. At this time, the sewer line
was not installed and there was no building in place. Photographs and notes from that visit have
been included as part of this report. Following the August 2015 visit, the OWTS system was
substantially completed and system components were backfilled and buried without final
observation.
Jordan Architects
November 13, 2018
Page 2
We were contacted in February 2018 and requested to observe the system components with
respect to conformance with the original design. We visited the site on February 26, 2018 to
observe the installed system components. At that time, there was approximately 12 to 18 inches
of snow cover at the site, and most of the OWTS components and STA were not observable.
The location of the septic tank was identified during this visit and plans were made to return to
the site after the snow had melted.
We returned to the site on April 12, 2018 after the snow cover had cleared from the site. We
were able to identify the general location of the OWTS components and measure the size of the
STA, verify type and size of septic tank, type of pump, cleanout location, and sewer and effluent
line locations. Unknown portions of the system not identified during our visit included
distribution line size and orifice spacing and size, and depth of the sewer line from the
garage/shop to the septic tank. An additional site visit was planned to unearth an area of the
STA as well as a portion of the sewer line from the garage/shop to the septic tank to observe
these components.
We returned to the site on June 4 to observe portions of the distribution lines and sewer line. An
area at the east end of the STA had been unearthed to expose the STA distribution lines. We
observed that the lines, orifice spacing and size were in general conformance with the design.
An area of the sewer line, near the septic tank, was unearthed and exposed. The sewer line was
observed to have blue board insulation above it, and the depth to the top of the pipe was
measured at 26 to 30 inches below the existing grade in the gravel driveway near the septic tank.
The slope of the sewer line was measured at about 7% down toward the tank at a distance of
about 5 feet from the tank.
We returned to the site on November 1, 2018 to observe the completed installation and observe a
pump test. Upon arrival and examination of the pumping system, it was noted that the pump
floats were improperly installed, and that the pump was not functional. We were notified that
these items would be fixed and that we would be called for a return visit.
We were notified that the pump system had been fixed and was functional and returned to the
site on November 7, 2018. At this time the pump floats had been properly installed and we
observed a successful pump test of the system. Also, we were informed that the grade of the
sewer pipe had been adjusted to conform with the recommended slope and that additional cover
soil and insulation had been placed over the sewer pipe. The pipe was backfilled at this time so
direct observation by us was not possible.
H -P KUMAR
Project No. 18-7-170
Jordan Architects
November 13, 2018
Page 3
Discussion and Recommendations: Based on our observations of the constructed OWTS
system and reported items, it is our opinion that the system components were generally
constructed in conformance with the referenced OWTS design. All other recommendations
presented in the referenced OWTS design report should be followed unless otherwise noted.
Significant design changes to the OWTS may require additional analysis or modifications to the
recommendations presented herein.
If you have any questions or need further assistance, please call our office.
Sincerely,
H -P=_ KUMAR
Jarlles A. Parker, P.E., P.G.
Reviewed by:
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David A. Young, P.E 1I 3. -216
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Attachments: Figure 1 — As -Built Site Plan
OWTS As -Built Photograph Log
H -P; KUMAR
Project No. 18-7-170
Photo Log
8480 County Road 117
Garfield Coun , Colorado
Garage/Shop in Relation to Septic Tank
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Project No. 18-7-170
Photo Log
8480 County Road 117
Garfield Count , Colorado
:112-
41.
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et rm
Ilogno
Backfilled Tank
Backfilled Tank and STA from Direction of Garage/Shop
Project No. 18-7-170
Photo Log
8480 County Road 117
Garfield Count , Colorado
Side View of STA
Biotube Vault in Septic Tank
0820.2015
Project No. 18-7-170
Photo Log
8480 County Road 117
Garfield Count , Colorado
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SOIL TREATMENT AREA
AGGREGATE THAT IS 30 FEET
LONG BY 10 FEET WIDE
CONSTRUCTED OVER A 2
FEET MINIMUM THICK SAND
FILTER
SOIL TREATMENT AREA
SAND BASAL AREA
THAT IS 38 FEET LONG
BY 18 FEET WIDE
1-1/2"
EFFLUENT
TRANSPORT
LINE
iN
•
r
1,000 GALLON, THREE CHAMBER
SEPTIC TANK WITH BIOVAULT AND
ORENCO PF3005 PUMP
4" SEWER LINE
GARAGE/ADI,)
18-7-170 1 H -P- KUMAR
OWTS AS -BUILT SITE PLAN
Fig. 1
Photo Log
8480 County Road 117
Garfield County, Colorado
Septic Tank and Field Under Construction
Tank, Sewer Line with Insulation, and Cleanout
Project No. 18-7-170