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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: a� David A. Young, P.E 1I 3. -216 6.4,<-0./.../..ree JAP/ksw 440-41101111111 , f 1V tL '% 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 �.W Project No. 18-7-170 Photo Log 8480 County Road 117 Garfield Count , Colorado :112- 41. - 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 5�. Jam{ i�su•�i{„�, fir L-�rS •.r� � ' � `� ik ' •r -tet• �} i y• , b•c f � r -fi ...r .. ~ r P . y r 4 i .'-. z. .. . � 5' iS r .�; s...er"' `Iris y •: 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