HomeMy WebLinkAboutEngineer's Installation Report 04.17.2019April 17, 2019
Barnicoat, Jason & Tanya
1475 County Road 129
Glenwood Springs Co 81601
Barnicoat, Tanya D<tanya.barnicoat@coloradohomes.com>
Helffenstein, Dennis A & Diana M
18425 Sunburst Drive
Monument CO 80132
email: helffen3@gmail.com
RE: Certification Letter, On-site Wastewater Treatment System (OWTS), Residence, 1475 C.R. 129,
Glenwood Springs, Sec: 2 Township: 6 Range: 89 TR in Lot 2, No Name, CO
SE Job No. 19033, Parcel No: 2185-021-00-008. Garfield County Permit: SEPT -03-19-5654
Dear Ladies and Gentleman:
Pursuant to County requirements, this letter provides documentation that the new Onsite Wastewater
Treatment System (OWTS) recently installed at the above referenced site is in compliance with the
permitted design. Sopris Engineering inspected the excavations, soils, materials and the installation of the
system components at various times during construction, prior to final backfill and after all installations
were completed. The system constructed on site was designed and built to serve the needs of the single
family residential structure. The installed residential system was designed for a maximum 3 -bedroom
residence. Sopris Engineering performed several visits to inspect the as built conditions of the constructed
system. We have coordinated our efforts with the earthmoving contractor, Larry Martin Construction, that
constructed the system. The as built conditions and installation of the new OWTS components is in
compliance with Garfield County OWTS Regulations; the recommendations and specifications delineated on
the civil design plans, C1-OWTS Plan & the OWTS Design Report, dated 3-7-2019, by Sopris Engineering. The
design criteria and system sizing information is summarized below. The As -built OWTS treatment bed has
been constructed in the locations shown on the attached As -Constructed Record Drawing. The OWTS
installation was performed by Larry Martin Construction, Glenwood Springs, CO, (970) 945-7227.
Design Criteria and As -built System Component Installation and Sizing
The system was designed based on the design criteria approved for use of pressure dose sand filters (SF) systems.
The OWTS includes the installation of a 1,000 gallon 2 -compartment reinforced plastic septic tank and a 30 -inch
ribbed PVC pump basin equipped with an Orenco Systems simplex high head pump in a Biotube vault with
associated piping and controls. The SF field consists of two beds installed to provide for equal pressure distribution
of effluent across a 565 S.F. treatment/absorption SF field with 24 -inches of filter sand below gravelless chamber
spray shield units. The effluent is dosed across the three distribution rows via an individual custom perforated
/pressure distribution pipe installed in each 27 feet by 10.5 feet sand filter beds. The OWTS Design Capacity is
based on a 3 bedroom residence.
502 Main Street • Suite A3 • Carbondale, CO 81623 • (970) 704-0311 • Fax (970) 704-0313
SOPRIS ENGINEERING • LLC
civil consultants
OWTS Certification Letter
Barnicoat Residence
SE Job No. 19033.01
April 17, 2019
Page 2
Design Calculations OWTS
Minimum population based on 3 bedrooms = 6 persons.
Gallons per day per person =75 gal/person/day, No peaking factor
Max. Design flow (Qd)gallons/day = (# of people) x (avg. flow)gaUperson/day.
Design flow Qd = 6*75=450 gpd
Sub Surface Conditions and Testing
Subsurface soil investigations and USDA soil texture method tests were performed by Sopris Engineering. The soils
below 3 to 8 inches of topsoil consist of medium dense gravelly sandy loam material to 1.5 to 5 feet below the
surface with 25% rock content and scattered boulders . No limiting soil conditions were encountered. The soil
appears to be consistent across the site.
The native soils sampled from 2-3 feet below the surface are characterized as a soil type 2 consisting of sandy loam
texture with moderate granular structure. This soil has an effective loading rate for conventional soil treatment of
0.6 Gal/S.F./day for a level 1 conventional treatment system. Due to limited area and to provide optimal treatment
an intermittent sand filter was installed to provide for level 3 treatment.
Intermittent Sand Filter Treatment Unit/ Absorption System Design
The treatment/absorption field is designed based on utilizing the effective Long Term Acceptance Rate (LTAR) for
an intermittent sand filter treatment system utilizing pressure dosed distribution laterals and gravelless chamber
units as spray shields providing level 3 treatment prior to infiltration into the native soils. The new treatment system
will consist of a fully pressure dosed sand filter Treatment bed System with a 24 -inch layer of filter sand (ASTM -
C33, "Concrete sand").
Long Term Acceptance Rate (LTAR)
Considering the application of the new state regulation 43:
Receiving Wastewater Treatment Level 1; loading rate for sand filter is (0.8 gal./S.F./day) for the minimum 24"
depth of sand treatment media;
Loading factors; (Table 10-2, pressure dosed application bed = 1.0 )
A(sf) = Qd .: A = Area;
LTAR LTAR = 0.8 Gal/S.F./day for ASTM -C33, " washed Concrete sand"
Qd = flow (gal/day) = 450 gpd
L.F.1=1.0 pressure closing
A(sf) = 450 gpd x 1.0 = 563 S.F.
0.8 Gal/S.F./day
Installed two 27' by 10.5' sand filter beds. Excavated the beds to a maximum 4.0 depth below finish grade, scarified
and backfill with 24 -inches of ASTM -C33, "Concrete sand". Typical for each bed, installed 3 runs of custom
perforated distribution laterals on top of sand layer and covered with Quick -4 chambers in 3rows with 4 chamber
units per row for use as pressure dose spray shields, as delineated on the plan. The beds are dosed from a simplex
high head distribution pump system installed in the dosing basin.
OWTS Certification Letter
Barnicoat Residence
SE Job No. 19033.01
April 17, 2019
Page 3
The septic tank effluent is pressure dosed from the pump chamber to a manifold pipe at the head of each
distribution lateral rows via a 1.25" discharge pipe installed with a continuous slope to allow drainage into
the field and drainage back into the tank. The effluent is equally pressure dosed through 1.25 -inch custom
perforated distribution laterals running the length of the treatment bed rows installed on top of the installed
sand filter media. The distribution lateral pipes have 3/16 -inch orifices drilled every 2.0 feet oriented
upward to spray onto the infiltrator quick -4 chamber. Ball valves are installed on the end of each
distribution lateral centered below the 4 -inch inspection ports on each end chamber. A piezometer
monitoring well pipe riser with threaded cap was installed on the East side of each bed.
OWS Operation and Maintenance
Ownership of the system and responsibility for maintenance and repair will remain with the property
Owner. The Owner is encouraged to retain the services of qualified personnel to inspect the OWTS and to
perform all maintenance and repairs necessary to ensure that the system components are maintained in
good operating condition and suitable vegetative cover is established on the fields. The components of the
OWTS system should inspected within 60 days of being placed into normal operation and should been
inspected and maintained bi-annually. The tank, absorption field and other system components should be
visually inspected bi-annually for debris, damage, leaks, or other potential problems. In general, for a
properly utilized system, septic tanks should be pumped every 2 - 4 years. The effluent filter should be
cleaned every six months and at the time of pumping. Absorption fields should be maintained with
suitable vegetative cover and kept free of root invasive plants. Positive surface drainage away from the
absorption field should be maintained.
If you have any question or need any additional information, please call.
Sincerely,
SOPRIS ENGINEERING, LLC
Paul E. Rutledge
Design Engineer
Yancy Nichol, PE
Principal