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113 NINTH STREET,
SUITE 214
P.O. Box 1458
GLENWOOD SPRINGS,
COLORADO 81602-1458
August 5, 2015
OSWT Engineers report for home at 115 County Road 301, Parachute,
Colorado
Lot 7, Horbefytz Subdivision
The lot has a functional 1,000 gallon septic tank to serve the requirements of
the 3 bedroom home. The previous leach field, which was located in the dry
wash to the north of the home, failed and required replacement. A site
examination was conducted and it was decided to locate the new leach Geld in
the front yard of the home. Three test pits, 4 feet deep were excavated and
filled to a depth of 2 feet and allowed to soak overnight.. They were all
drained the next morning. No ground water or bedrock was encountered in the
test pits. The soil profiles in all 3 pits were similar, being predominately
sandy loam with a few small rocks. They were refilled the following day to a
depth of 2 feet and the percolation rates were measured. The percolation rates
ranged from 5 to 9 minutes per inch.
Table 6-1 indicates the design flow for the 3 bedroom home is 450 gallons per
day.
Table 10-1, soil type 1 states a treatment level of 0.80 gallons per day per
square foot of leach field surface. Infiltrator chambers will be used for the
leach field. Table 10-3 states that size adjustment can be modified by 0.7
when chambers are used.
Therefore: 450/0.8 (0.7) = 393.75 square feet of leach field surface.
Infiltrator chambers are 3 feet wide which will require: 393.75/3 . 131.25
liner feet..
The chambers are 6.25 feet long, therefore 393.25/6.25 -21 chamber units.
Design of system consists of 3 runs of 7 chambers with a bed elevation of
5083.76. Backfill over chambers to elevation 5086.3.
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593
/Jerome F. 5933