HomeMy WebLinkAboutProfile Pit Evaluationt(+rt l(umar & Associates, lnc.@
Geotechnical and Materials Engineers
and Environmental Scientists
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
emaiI: kagleuu'ood@kumarusa.com
u'rvu'. kuntarusa. colr'ìAn Ëmploycü OwnÊd Compcny
Office Locations: Denver (HQ), ParkeL, Colorado Springs, Forl Collins. Glenwood Springs, and Surnmit County, Colorado
October 26,2021
Generalandpro
Attn: Gabriel Michael
P.O. Box 133022
Dallas, Texas 75313
generaland srlail.con-ì
Subject:
Project No. 20-7-528.02
Profile Pit Evaluations, Proposed OnrSite Wastewater Treatment System, Shaw
Property, 1773 County Road 241, Garfteld County, Colorado
Dear Gabriel:
As requested, Kumar and Associates performed profile pit evaluations at the subject site. We
understand our findings will be used by others in the design of the on-site wastewater treatment
system (OWTS). This report summarizes our findings and general design recommendations
based on the subsoil conditions encountered. The services are supplemental to our professional
services agreement to you dated September 15,2020.
Background Information: We previously performed a subsoil study for the proposed accessory
building (ADU) at the site and submitted our findings in a report dated October 15, 2020,
Project No. 20-7-528. The ADU will reportedly be connected to the new OWTS.
Site Conditions: The proposed soil treatment area (STA) is currently vacant. The existing
residence is uphill and to the west of the explored area. The terrain is moderately sloping down
to the east and south. Vegetation consists of native grasses and weeds with scattered sagebrush
and juniper and pinyon trees. East Elk Creek is about 150 feet east of the profile pits.
Subsurface Conditions: The field exploration for the OWTS was conducted on June 4, 2021.
Two profile pits (Profile Pits I &,2) were excavated with a mini-excavator at the approximate
locations shown on Figure 1 to evaluate the subsurface conditions at the proposed soil treatment
area for the OWTS. The pits were logged by a representative of Kumar & Associates. Logs of
the profile pits are provided below.
Log of Profile Pit I
Depth USDA ClassiÍication
0-/2'TOPSOL; Organic Loarn, firm, slightly moist, dark brown
Y2'-8'SANDY LOAM; stiff, slightly moist, reddish brown. Moderate blocky structure.
a
o
Bottom of pit @ I feet.
No free water or redoxintorphic features observed during pit excavation.
Generalandpro
October 26,2A21
Page2
Log of Profile Pit 2
The soils encountered at Proñle Pits 1 anó2 consisted of about Yz faot of organic topsoil
overlying Sandy Loam down to the pit depths of 8 feet. Hydrometer and gradation analyses
were performed on a disturbed bulk sample of the soils from Profile Pit 2 from 3% to 41/z feet
depth with results provided on Figure 2. The tested sample (minus No.10 size sieve fraction)
classifies as Sandy Loam per the USDA system. No free water was encountered in the pits nor
indications of seasonal high groundwater were observed at the tirne of the pit excavations.
Discussion: The profile pit evaluations at the STA indicate a long-term acceptance rate (LTAR)
of 0.60 be used at this site for Treatment Level 1 (TL-1) for a system in the Sandy Loam soils.
Limitations: This study has been conducted in accordance with generaliy accepted engineering
principles and practices in this arca afthis time. We make no warranty either express or implied.
The recommendations provided in this report are based on the profile pit evaluations and soil
texture analysis, the proposed construction and our experience in the area. Variations in the
subsurface conditions may not become evident until excavation is performed. If conditions
encountered during construction appear different from those described in this report, we should
be notified so that re-evaluation of the recommendations may be made.
If you have any questions or need further assistance, please call our office.
Respectfully Submitted,
Kunlar & ¡dssociates, Inc,
#^**W
Shane M. Melio, Staff Engineer
Reviewed by:
.l: I
David A. Young, P
SMM/kac
attachments Figure
Figure 2 -
e Pits
on Test Results
Cc: Richard Lyon l.it011'¡
Depth IJSDA Classilication
0-Yz'TOPSOIL; Organic Loam, firm, slightly moist, dark brown.
Yz'-80 SANDY LOAM; stiff, slightly moist, reddish brown. Moderate blocky structure
a
a
e
Bottom of pit @ 7 feet.
Disturbed bulk sample at 3Yz to 4%feet.
Nofree water or redoximorphicfeatures observed during pit excavation.
Kumar & Associates, Ine'r"
1'rr.lìftli1,l
Projecr No. 20-7"528.02
EX. BARN
(s,ooo sF)
0
SCALE- FEET x. FENCtLINT (rve.)
PR. 1 _STORY
CCESSORY BLDG.
(1,600 sF)
+
PROFI
PIT 2
+
+
RTATMENT
AREA
T
PROFI L
PIT 1
EX. SOIL
TANK
EX.
SEPÏIC
EX. DENSE
rnrrs/enus
(TYP. )
EX. 1 _STORY SFR
(z,7zo sF
EX. WT
-
tta'
x
X
x
Fig. 1LOCATIONS OF PROFILE PITSKumar & Associates20-7 -528.02
100
90
ao
70
60
50
40
30
20
10
0
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME REÀDINGS
24 HRS 7 HRS l MIN
U,S. STANDARD SERIES CLEAR SQUÀRE OPENINGS
i
o
10
20
30
40
50
50
70
ao
90
100
.250 .500 1.OO 2-OO 1-75
.o45 152
DIAMETER OF PARTICLES IN MILLIMETERS
CLAY COBBLES
.002 mm .02 .05 .1 .25 .5 1 Zmm 5 20 76
SAMPLE OF: SANDY LOÄM
FROM: PROFTLE PrT 2 AT 3-1/2 TO 4-1/2 FrEf
ENTIRE SAMPLE
GRAIN SIZE(--)SIEVE SIZE % FINER
127.00 5 100
76.00 100
38.1 0 1-1 /2"100
19.05 3/4"f00
9.50 3/8"98
4.75 #4 96
2.00 #10 95
1.00 #18 88
0.50 #35 EO
0.25 #60
0.1 06 #1 40 5l
0.045 #325 27
PARTICLE SIZE DISTRIBUTION %
COBBLES 0
GRAVEL 7
SAND 66
SILT 21
CLAY Þ
PORTION OF SAMPLE
PASSING #10 S|EVE
PARÏICLE SIZE DISTRIBUTION %
SAND
SI LT 23
CLAY
TOTAL SAMPLE REIAINED ON f10 SIEVE: 7%
GRAIN SIZE(.-)TIME PASSED
( min)% FINER
0.037 1 24
0.019 4 18
0.009 19 IJ
0.005 60 11
0,002 435 6
0.001 1 54s 4
PERCENï OF MATERTAL RETATNED ON #10 STEVE
PASSING 3/4" SIEVE: 10O%
NOïE: Hydromeler Anolysis wos performed on o
bulk somple following screening of oll moieriol
lorg6r lhon the $10 sieve (2.0 mm) per USDA
g uidelines.
These lesl r€sulls opply only lo lhe
somplos wh¡ch were lesled. The
l€sllng reporl sholl nol be 16produc€d,
excêpl ln lull, w¡lhoul lh€ wrlllon
opprovol ol Kumor & Associol€s, Inc.
Si6v6 onolysis lesllng is performed in
occordonce wlth ASTM 0422, ASTM C136
ond/or ASTM 01140.
SILT SAND GRAVEL
FINF co.V, FINE FINE N,lEDIU]!1 CO v. co.FINE ljlEDlUlV COARSE
20-7 -528.02 Kumar & Associates USDA GRADATION TEST RESULTS lig. 2