HomeMy WebLinkAboutAs-built Report 07.25.2016" YiJuly 25, 2016
Andre J. Ulrych
730 Latigo Loop
Carbondale, CO, 81623
ajulrych@gmai[.com
RE: AS BUILT, Onsite Wastewater Treatment System (OWTS), Ulrych Residence, 9183 State
Highway 82, Garfield County, Colorado
SE Job No. 26297.01 Parcel Number: Parcel Number: 2393-202-00-110
Dear Andre:
Pursuant to County requirements, this letter provides documentation that the new Onsite Wastewater Treatment
Systems (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 was completed. The system
constructed on site was designed and built to serve the needs of residence currently under construction. The
installed system was designed with a maximum treatment capacity equivalent for typical 3 -bedroom home.
Sopris Engineering performed site visits to inspect and document the as -built conditions of the constructed
system. Inspections were coordinated with the earthmoving contractor, Piffco. The as -built conditions and
installation of the new OWTS components is in compliance with Garfield County Regulations; the
recommendations and specifications delineated on the civil OWTS design plan, C3-OWTS Plan, stamp dated
3-11-2016, by Sopris Engineering. The design criteria and system sizing information is summarized below.
An As -built OWTS record drawing is attached delineating the As -built descriptions and location of the
components.
Design Criteria and As -built System Component Installation
The system was designed based on the design criteria approved for use of Soil Treatment Unit (STU) systems.
The OWTS includes the installation of a 1000 gallon 2 -compartment concrete septic tank with concrete risers
and lids installed at the surface. The tank was installed with an inlet sanitary tee and an outlet effluent filter
sanitary tee. A gravity schedule -40 sewer pipe with a cleanout is installed from the residence to the tank. The
soil treatment unit (STU), consists of 3 leaching chamber trenches that provides 630 S.P. of total absorption
area. The septic tank effluent is equally distributed by gravity, via a distribution box, to the STU. The effluent
is distributed through a concrete distribution box installed with risers and lid at the surface and individual
distribution pipes connected to the head end cap of each chamber trench. Observation ports with caps were
installed on each end chamber unit. The design is in compliance with the current County regulations with
design calculations based on the soil type, texture and structure with an appropriate long term acceptance rate
(LTAR).
502 Main Street • Suite A3 • Carbondale, CO 81623 • (970) 704-0311 • Fax (970) 704-0313
Sorais ENGINEERING • LLC
civil consultants
AS -BUILT, OWTS
Ulrych Residence
SE Job No. 15178.01
July 25, 2016
Sub Surface Conditions and observation
Subsurface soil investigations and USDA soil texture method tests were performed by Sopris Engineering
on August 21, 2015. The soils were tested to determine the hydraulic loading rate and the appropriate
absorptive surface depth in the native soils. A shallow and deep excavated pit was observed in the west
central portion of the site. The soils below 6 to 12 inches of topsoil consist of medium dense silt loam with
moderate granular to fine grained massive structure overlying cobbles and gravel in a sandy silty clay loam
matrix to the 7 foot depth explored.
The native soils sampled from 1-3 feet below the surface are characterized as a soil type 2A consisting of
silt loam texture with moderate granular to fine grained massive structure. This soil has an effective
loading rate for conventional soil treatment of 0.50 gal/S.F./day for a level 1 conventional treatment
system. The equivalent percolation rate is approximately 26-40 minutes per inch. Increased quantities of
cobbles and gravel are encountered at depths below 4 feet. No free water was encountered in excavations
on site. Groundwater levels are expected to be well below 10 feet from the existing surface grades along
down gradient western portion of the site. The soils appear suitable for a conventional shallow absorption
field consisting of gravelless infiltration chamber units. No free water was encountered in excavations on
site. No excessive boulders or cobbles were encountered during excavation. Observations of the soils, in the
excavation during construction, appeared to be consistent with the previous subsurface soil investigation.
Design Flow
The design flow is calculated as follows:
The new OWTS shall be based on a minimum 3 -bedroom capacity for single family residence.
From the Garfield County OWTS Regulation 43 ;
Minimum population based on 3 bedrooms @ 2 person /bedroom = 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)gal/person/day.
Design flow Qd = 6'75=450 gpd
Treatment -Soil Treatment Unit/ Absorption System Design
The treatment/absorption field was designed based on utilizing the effective Long Term Acceptance Rate
(LTAR) for the native soils and the application of appropriate loading factors for a soil treatment unit
system utilizing gravity distribution to gravelless chamber trenches. The new treatment system and
absorption field consist of gravity distribution of septic tank effluent via a distribution box to individual
chamber trenches with treatment across the native soil absorptive surface.
Long Term Acceptance Rate (LTAR)
Considering the application of the new state regulation 43:
Receiving Wastewater Treatment Level 1; loading rate for silt loam is (0.50 gal./S.F./day) for soil type
2A.; Loading factors; (Table 10-2, Gravity application trenches = 1.0) and
(Table 10-3, gravelless chambers = 0.7)
AS -BUILT, OWTS
Ulrych Residence
SE Job No. 15178.01
July 25, 2016
A(sf) = Qd x L.F.: A = Area;
LTAR LTAR = 0.50 Gal/S.F./day for silt loam
Qd = flow (gal/day) = 450 gpd
L.F.1=1.0 Gravity Distribution
L.F.2=0.7 Chambers
A(sf) = 450 gpd x 1.0 x 0.7 = 630 S.F.
0.50 Gal/S.F./day
Number of quick -4 chambers:
630S.F = 50 chambers Use 54 chambers
12 S.F./Chamber
54 Quick -4 chambers in three trenches 74' long by 3' wide with I8 chambers units per trench plus two end
caps was installed as delineated on the attached As -Built Record drawing.
OWS Operation and Maintenance
Ownership of the system and responsibility for maintance and repair will remain with the property Owner.
The�wner is encouraged to retain the setwices of qualified personnel to inspect the OWTS and to perform all
main nance an pairs necessary to tsure that the system components are maintained in good operating
Ott and su e vegetative cosr is Atablished'on.the fields. Th components of the OWTS system
fit peted wi 30 days bf brig plgcecJ into operation and show been inspected and maintained bi-
annually. The tatilt7i 'sorption field and other sygtei icompone s 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 3 - 5years..A2 effluent filter should be cleanq every six months and at the time of
pumping. Absorption fields should be maintained with suitable vegetatiie 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
- 411
aul Rudge .
• iowr
r
Yancy Ni
Principal