HomeMy WebLinkAboutEngineer's Installation Observation Letter-Revised 05.01.24
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MEMORANDUM
TO: Ted White, P.E.
2014 Blake Avenue
Glenwood Springs, CO 81601
TWhite@garfield-county.com
FROM: Terry Bendetti, P.E.
Caliber Engineering
DATE: 05/01/2024
RE: Certification Letter for Construction of the Onsite Wastewater Treatment System
(OWTS) on Garfield County Parcel Number 212733300358, 308 Cindy’s Way, Rifle,
Colorado 81650, Garfield County, Permit Number SEPT-09-17-4950.
Dear Ted,
Thank you for your email on 4/23/2024 asking for verification of the infiltrator size placed for the
subject OWTS permit. As I responded in my email reply, this information was overlooked on the
engineers inspection and could not be verified through photographs taken at the time of
inspection.
Inspection photographs show 4 rows of infiltrators with 10 infiltrators per row. Per the design,
the STA was to have 4 rows of infiltrators, each row having 10 infiltrators, based on using the
Arc-36 infiltrator. This would meet the STA design requirement of 600 square feet (sf), 4 x 10 x
15. However, the photographs did not show the model of infiltrator placed, nor was it recorded
at the time of the engineer’s observation inspection.
The inspection photographs show observation ports were installed at the beginnings and ends
of each infiltrator row, therefore, if the correct infiltrator was installed the distance between
observation ports should be a minimum of 50 feet, since the Arc-36 has a length of 5 feet and
there are 10 per trench.
A site visit was made, and measurements taken between each rows beginning and ending
observation port. The average distance measured was 41 feet. This indicates the infiltrators
placed have a length of 4 feet and an effective floor area of 12 sf, making the STA footprint 480
sf, 120 sf short of the required design.
On 4/24/24 the Contractor, Owner and Engineer met on site and determined the best approach
to meet design requirements for the STA was to add another row of 10 Quick-4 infiltrators,
which have an effective floor square footage of 12 sf. The fifth row will add 120 sf of floor area
to the STA, making the total STA floor area 600 sf, which meets design requirements.
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The Contractor installed the fifth row of 10 infiltrators on 4/29/24; the installation was observed
by your Department on 4/30/24. Caliber Engineering, Inc. inspected the installation on the
morning of 5/01/24; and the Contractor covered the infiltrator trenches using excavated material
on 5/01/24.
All other components were properly installed and relocated component locations met
requirements of Garfield County’s Regulation 43.
The attached revised record drawing shows as constructed locations for components of the
OWTS, including the fifth row of infiltrators.
Sincerely,
Terry Bendetti, P.E.
Caliber Engineering
Attachments (1) OWTS Record Drawing
05/01/2024