HomeMy WebLinkAboutAS-Built-OWTS-826-Elk Run-letter.pdfJuly 17, 2014
Paul W. Nelson
pablonelsoni@yahoo.com
Coldwell Banker Home Owners Realty
RE: AS --BUILT, On-site Wastewater Treatment System (OWTS), 826 Elk Run Road, New Castle,
Garfield County, Colorado
SE Job No. SE Job No. 14092.01 Parcel Number: 212525109013
Dear Paul:
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 designs. 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 complete. The OWTS constructed on site consisted of a replacement treatment/absorption field, new
distribution piping and distribution box. The components were installed to replace the failed chamber field
constructed in 2002. The existing sewer pipe and septic tank were maintained for continued use after
extensive tank service and retrofit with additional risers and an effluent filter. The upgraded OWTS was
designed and built to serve the needs of the existing 5 -bedroom residential structure. Sopris Engineering
performed several visits to inspect and document the as built conditions of the constructed system. We
have coordinated our efforts with the earthmoving contractor that modified and constructed the new system
components. The as built conditions and installation of the new OWS components is in compliance with
Garfield County Regulations; the design presented in the Sopris Engineering design drawing, dated June 9,
2014. An As -built OWTS record drawing is attached delineating the As -built descriptions and location of
the components.
As -built System Component Installation
The existing Copeland two chamber 1500 gallon concrete septic was pumped and cleaned. The access
openings were fitted with concrete risers to reset the lids at the surface. A 4" effluent filter was installed in
the tank outlet sanitary tee. The tank was observed to be in good condition, watertight and set level. A
cleanout is installed on the sewage line off the exterior wall of the residence.
Treatment/Absorption field: Geotextile Sand filter with equal gravity distribution.
Installed 40 In Drain units (model EL00924) Field area divided into four treatment beds, each with two
GSF rows containing 5 units per row, placed at 4 feet on center over a 12 -inch deep filter sand layer
(concrete sand) approximately 25 feet long by 9 feet wide. The beds have an average excavation depth of
18 to 36 inches from finish grade. Each bed was constructed level. Effluent from the septic tank discharges
to an 8 port concrete distribution box, installed with risers and access lid at the finish surface grade. Four
individual distribution lines installed to equally distribute effluent to a solid manifold pipe tee at the head
of each of the four treatment/absorption beds. The flow splits in the manifold to the perforated distribution
lateral installed on the top of each GSF row. The 4" SDR -35 lateral pipe, installed level, runs the full
502 Main Street • Suite A3 ❑ Carbondale, CO 81623 ❑ (970) 704-0311 ❑ Fax (970) 704-0313
SOPRI$ ENGINEERING •
civil consultants
AS -BUILT OWTS, 826 Elk Run Road
SE Job No. 14092.01
July 17, 2014
Page 2
length of the GSF row and is capped on the end. A 4" vertical piezometer inspection port is installed near
the end of the most down gradient bed. A 4" vertical observation inspection port is installed on the end of
one of the distribution laterals in each bed.
Subsurface soil investigations and USDA soil texture method tests were performed by Sopris Engineering
in the area of the new proposed secondary treatment absorption fields. One profile pits was excavated by a
backhoe approximately 8 feet deep to allow observation of the soils in the area of the proposed field. The
soils at 2.5 and 3.0 feet deep were sampled and characterized by application of the USDA soil texture
method test. The soils were tested to determine the equivalent percolation rate based on the hydraulic
loading rate and to confirm the appropriate absorptive surface level suitable for conventional absorption
systems in native soils. The soils below nil to 4 inches of topsoil consist of medium dense, blocky to
granular slightly sandy clayey loam to clay loam clay material with gravel and cobbles to 0.3 to 3 feet
below the surface.
The underlying native soil observed from 2.5 to 8 feet below the surface grades consists of moderate
granular slightly clayey sandy loam with gravels and scattered cobbles. This soil has an effective loading
rate for conventional soil treatment of 0.7 Gal/S.F./day for a level 2 secondary treatment system. The
equivalent percolation rate is 40 mpi No free water was encountered in the exploration pit. Groundwater
levels are expected to be below a minimum of 10 feet from the existing surface grades.
The soils are suitable for treatment/absorption beds.
OWS Operation and Maintenance
Ownership of the system and responsibility for maintenance and repair will remain with the property
Owner. The owner is responsible for maintaining suitable vegetative cover on the beds. The components
of the OWS system should inspected within 30 days of being placed into operation and should been
inspected and maintained bi-annually. The tank, absorption field and other system components should be
visually inspected annually. In general, for a properly utilized system, septic tanks should be pumped every
3 - 4 years. The effluent filter should be cleaned annually 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
Cc: Garfield Co ing Department