HomeMy WebLinkAboutEngineer's Design Letter 11.07.2019DESIGN REPORT
ON-SITE WASTEWATER TREATMENT SYSTEM (OWTS)
4424 CR 154
GLENWOOD SPRINGS, COLORADO
GARFIELD COUNTY
November 7, 2019
Prepared By: Kenneth J. Brotsky, P.E.
558 Rio Oso Lane
Grand Junction, CO 81507
(970)216 8861
. INTRODUCTION:
This Report has been prepared at the request of Clayton Homes,
representative for the above referenced property. This Report
addresses the design of an On -Site Wastewater Treatment System to
serve a proposed residence. Public sewer service is not
available.
The procedures used in this report follow the "Garfield County
On -Site Wastewater Treatment System Regulations".
II. SOILS AND PERCOLATION TEST:
The site is quite steep with slopes varying from flat to 20%. It
is quite heavily covered with trees and shrubs. There are large
boulders exposed on the surface, some of these are up to 48" in
size.
The Owner provided a copy of a geotechnical report prepared by KC
Hamilton Engineering, Inc. dated June 8, 2008. That report
indicated that there is thin layer of top soil underlain by
clayey and gravelly sand with some cobbles and boulders. Test
pits were excavated down to depths of about 6 to 8 feet. Free
water not reported in the test pits.
Percolation test reported was 36 minutes per inch. Based on this
information a Long Term Acceptance Rate of 0.6 gallons per square
foot per day will be used for design.
A considerable amount of excavation, leveling, grading, and
removal of boulders will be required to prepare this site for the
proposed house and OWTS. An absorption bed will work the best for
an infiltration system. A 4 row bed of infiltrators will be
used. The bottom of the absorption bed will be set at 28" below
the final grade at the southeast corner of the bed.
III. SYSTEM DESIGN:
A. Estimated Sewage Flow: The proposed house will be 3
bedroom.
3 x 150
= 450 gallons per day
B. Septic Tank
Use a 1,000 gallon tank.
C. Absorption Bed:
The absorption bed size is calculated as
follows:
A = 450/.6
= 750 sq. ft.
Adjustment Factors:
Table 5.2 Method of Application is gravity
Factor 1.2
Table 5.3 Type of Distribution is Chambers
Factor 0.70
Bed Size required is 750 x 1.2 x 0.70 = 630 Sq. Ft.
Total Number of chambers required is 630/12 = 52.5 units
Use bed configuration, with 4 rows and 14 chambers per row
for a total of 56 chambers.
KENNETH J. BROTSKY,
No. 18843
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Piot plan must show the following markers as necessary:
Easements
Setbacks
Street:access
Water line
Sewer line
-GisteritAveI --
Buyer Is responsible to
front and rear doors. B
home .not co
Buyer
Buyer
Sepfic/leach$r1
Vbark-
frasipmpane
Frontlrear-dcors pf home
Other structures
E
Culverts
Buildover/shed roofs
Htsitne delivery Obstructions
:Distance of home to property lines
Distance between -structures
Garage/shed/shop AC placement
Concrete driveway width x length Portable restrwitalacement.-
mark placement of home and all other Items. Be sure to show hitch end and
uyer agrees to pay Seller's expenses for any costs Incurred to move or reset
is plot plan.
4f Date (11J-45/att
CMH 2
Date
Date %W / 23 /Z ra
USE END PLATE ON
EACH ROW
r --,r moi'
44yNCir--
0•0_
1°
N�
-- SEE MANIFOLD DETAIL
QUICK 4 INFILTRATORS
-- 4 ROWS ,14 EACH ROW
= 56 TOTAL
VENT/INSPECTION PORTS
SEE DETAIL. 4 RQD.
SEE SITE PLAN FOR
LOCATION OF PROPERTY
LINES
PLASTIC OR HDPR LID
FLAT OR DOMED'
FASTEN TO RISER
24" DIAMETER
HDPE RISER
FINISH CRADE
FASTEN TO TANK
• TANK WALL
TANK RISER DETAIL "
•
4".x4"z4"TEE
"PVC FROM TANK
4"z90°:]
*ROWS INFII'.'PRATORS
USE SIDE INLETS
s•= ,
MAI!TIFOLD DETAIL-
1000 GALLON
SEPTIC TANK
SEE NOTES.
SET BOTTOM OF INFILTRATORS
28" BELOW EXISTING GRADE
1 AT SOUTHEAST CORNER OF BED
TOPOFBOUSE
FOUNDATION 100.0
MUST BE AT LEAST
100' FROM WELL
CLEANOUT NORTH
SCALE:.1" = 20'
PROPOSED HOUSE
3 BEDROOMS
VENTMISPECTION TUBE I
FLOW -LINE PROFILE
SCHEMATIC
NOT TO SCALE
•. 0RAPBO0Yal2
QUICK 4 INFILTRATORS
4 ROWS 14 EACH ROW
= 56 TOTAL
SET BOTTOM OF INFILTRATORS
28" BELOW EXISTING GRADE
AT SOUTHEAST CORNER
OF BED
SET BOTTOM OF INFILTRATORS
28" BELOW EXISTING GRADE
AT SOUTHEAST CORNER
OF THE BED
NOTES
1. Contact Engineer for inspections at the following times: (Allow at least 24 hours advance
notice). (Engineer will coordinate inspection time with Garfield County)
1) When installation of the infiltrators, piping, and septic tank is complete but not
covered, and ready for final inspection.
Engineer is Kenneth J. Brotsky (970) 216-8861
2. The pipe -from the house plumbing to the septic tank and from the tank to the absorption bed
shall be 4 inch diameter, SDR 35, PVC sewer pipe. The pipe shall be laid at a minimum slope
of 1/4 inch per foot.
3. INFILTRATOR units to be installed per manufacturers recommendations. Units to be "Quick 4".
Geo -textile landscaping fabric shall be draped over the Infiltrators as shown.
4. The septic tank shall be a 1,000 gallon, 2 -compartment tank approved by Garfield County.
5. All construction shall be in accordance with Garfield County On -Site Wastewater Treatment
System Regulations", most current edition.
6. Any changes to the layout on these drawings must have the approval of the Engineer prior to
construction. Any unauthorized changes may have to be corrected. Any costs for redrawing of
plans required because of unauthorized changes may be back charged to the installer.
7. Installer responsible for calling for "Locates".
8. An OWTS Permit must be obtained from Garfield County prior to starting installation of
system.
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SITE PLAN, DETAILS, & NOTES
ON-SITE WASTEWATER TREATMENT
SYSTEM (OWTS)
4424 CR 154
GLENWOOD SPRINGS, CO.
GARFIELD , COUNTY
DWG1OF1
NnVF.MRER 5.2019