HomeMy WebLinkAboutLARIMER COUNTY COURTHOUSE - SITE PLAN ADVISORY REVIEW - 37-98A - SUBMITTAL DOCUMENTS - ROUND 1 - ENVIRONMENTAL REPORTTABLE 1
SUMMARY OF FIELD ATHA RESULTS
PROJECT NAME: Larimer County Justice Center Limited Phase II ESA
PROJECT LOCATION: Block 31, City of Fort Collins, Colorado
PROJECT NUMBER: 20965087
Approximate . PID Reading
Sample Sample Depth (PPM as Organic Vapor
Name Date (Feet) Vapor in Air)
Boring 1
6/20/96
1 to 2
NU
Boring 1
6/20196
4 to 5
ND
Boring 1
6/20/96
8 to 9
ND
Boring 3
6/20/96
1.5 to 2.5
ND
Boring 3
6/20/96
4 to 5
1
Boring 3
6/20/96
8 to 9
ND
Boring 7
6/20/96
1.5 to 2.5
ND
Boring 7
6/20/96
4 to 5
3
Boring 7
6/20/96
6 to 7
8
Boring 8
6/20/96
1.5 to 2.5
2
Boring 8
6/20/96
4 to 5
1
�^ Boring 8
6/20/96
8 to 9
ND
Boring 9
6/21/96
1 to 2
1
Boring 9
6121/96
4 to 5
1
Borina 9
6/21/96
8 to 9
ND
NOTES:
1. Sample Locations are shown on Figure 1 in Appendix A.
2. ATHA = Ambient Temperature Headspace Analysis
3. PID = Photoionization Detector
4. PPM = Parts Per Million
5. ATHA is used as a qualitative indicator of petroleum hydrocarbon contamination and
should not be construed as a quantitative analyses of contamination.
6. ND = Not Detected in the PPM range.
lrerracon
Form 101-1.87
1I:1 ...NU—_-3Y---1fV_.._IU. , 11N
CENTRE FOR ADVANCED TECHNOLOGY
2401 Research Boulevard, Suite 204
Fort Collins, Colorado 80526
(970)490-1414
VOLATILE ORGANICS
WATER ANALYSIS REPORT
QA/QC SURROGATE RECOVERY
TERRACON CONSULTANTS INC., EMPIRE DIV.
301 North Howes
Fort Collins, Colorado 80521
Fluorobenzene
Lab ID
Sample ID
Limits (75-125%.)
96280-1
Boring 1
106
96280-2
Boring 3
105
96280-3
Boring 7
105
96280-4
Boring 8
105
TECHNOLOGY LABORATORY, INC.
Page 2 of 2
Dale Received: 6/24/96
Dale Analyzed: 6/26/96
Project No.: 20965087
(% Recovery)
Bromotluorobcnzene
Limits (75-125%@
97
98
102
98
CENTRE FOR ADVANCED TECINOLOGY
2401 Research Boulevard, Suite 204
Port Collins, Colorado 80526
(970)490-1414
VOLATILE ORGANICS
WATER ANALYSIS REPORT
TERRACON CONSULTANTS INC., EMPIRE DIV.
301 North Howes
Port Collins, Colorado 80521
Lab ID Sample ID
96280-1
Boring 1
96280-2
Boring 3
96280-3
Boring 7
96280-4
Boring 8
TECHNOLOGY LABORATORY, INC.
Date Received:
6/24/96
Date Analyzed:
6/26/96
Projoct No.:
20965087
Date
Benzene
Toluene
Ethylbenzcnc
Xylcncs
TVPH-Purgcable
Sam led
Iig/L
ltp/I,
uC/L
m/L
mp/L
6/20/96
<0.5
<0.5
<0.5
<0.5
<0.5
G/20/9G
<0.5
<0.5
<0.5
<0.5
<0.5
6/20/96
<0.5
<0.5
0.8
1.6
<0.5
6/20/96
<0.5
<0.5
<0.5
<0.5
<0.5
Page 1 of 2
BTEX Method: EPA-8020
TVPH-Purgeable Method: EPA -Modified 8015
APPENDIX E
LABORATORY REPORTS
a
ICLIENT
SITE
Larimer County Facilities
Block 31
Fort Collins,
t,
O
J
DESCRIPTION
IH
cc
cD
x. Surface Elev.: 4987.5 ft.
An4.0
SPHALT
ASE COURSE
FILL-Silty_r�yey sand
wn, moist, loose
SANT)Y LEAN
rT AY VETH GRAVEL
Red/tan, moist, medium
LOG OF BORING No. 9
ARCHITECT / ENGINEER
PROJECT
1 e
�g
e.
WELL GRADED GRAVEL
WTT14 SAND & COR13LES
4
1a�
Tan brown, wet, dense
a
(Cobbles typical 8" max.)
a
18.0
WEaTHFRED SiLTSTONE/
20.0 C1AY3TONF
Blue,tblack, moist, moderately hard
CTT TCTONF/CT.AYSTONF
Blue/black, moist, hard
.5
BOTTOM
Pro osed Justice
Center
SAMPLES
TESTS
tY
L
2
a-
P--
ce
W
U
tY
Z\
F-c
tam
C
O
N
S
Z
W
>-U-
O0.
o
H1_
LL 0
U�li
�Ntl
.,
v
d
U
o
}
to
U
U
4987.2
4986.7
SM
1 ISS
12"
7
12
_
SCI
2
SS
12"
7
4983.5
bLI
3 IST
12"
16
111
2960
CL
4
SS
12"
5 1
14
5
5
SS
12"
5
6.
ST
12"
11 1
118 13450
7
SS
12"
5
15
=AMA n 110
15-IGWI 8 SS 12" ( 32 1 22 T—I
49L5 20
4958.0
25
-1 1 91 SS 1 12" 1 39 1 181 1 1
1of1
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-21-96
r
Q10.8WD• = 10.5' A•B• BORING COMPLETED 6-21-96
- - erracon RIG CME-55 FOREMAN DML
Water checked 3 days A.B. APPROVED NRS JOB x 20965087
a
LOG OF BORING No. 8 Page 1 of 1
CLIENT
ARCHITECT /ENGINEER
I Larimer County Facilities
SITE Block 31
PROJECT
City of Fort Collins, Colorado
Proposed Justice Center
SAMPLES
I
TESTS
0
U
DESCRIPTION
N
z
UJ
Z�
w
U_CD
C3 -
t H
2
W
W
0
W
>
O
to
3
H
W
O
ZZ
OW
HHZ
ONH
a-H
cc
tl
W
U
N
E
>
CL
>
U
W
F-O
f1J
H
O
>_LL.
MU
UO:U_
ZFfn
O¢LL.
HJ
Lo
Approx. SurfaceElev.: 4986,: ft.
c
o
Z
I
X
Nm
�
oo_
=vlo.
�a�
0.4 5" ASPHALT 4986.1
0•9 6" BASE COURSE 4985.E
SM
1
SS
12"
IS
3
2.5 4984.0
i
ETT T _y sand with gravel
Brown/black, moist, medium dense
2
ST
12"
27
102
1410
23/3/41
CLI
3
SS
12"
5
17
SANDY T FAN CLAY
Red, moist, medium
5
6.5 4980.0
o
e
GW1
4
SS
12"
41
9
WELL GRADED GRAVEL
.a
WTTH SAND & COBBT_ES_ _
Brown, moist to wet, dense
10
g
(Cobbles typical 12" max.)
g
14.5 4972.0
5
SS
12"
32
25
WEATHERED STT.TSTONE/
15
16.5 CT.AYSTONE 4970.0
Tan/gray, moist, moderately hard
STT TSTONE/CLAYSTONF _
6
SS
12"
50
17
Tan/gray, moist, hard
20
29.4
BOTTOM OF BORLYG
25
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN•SITU,'THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-21-96
wti g 9.3' W.D. = 9.3' A
. BORING COMPLETED 6-21-96
wt (erracon RIG CME-55 ioRE,�tAN DiviL
WL Water checked 3 days A.B. APPROVED NRS JOB a 20965037
a
LOG OF BORING No. 7
I CLIENT I ARCHITECT / ENGINEER
Larimer County Facilities
SITE Block 31
Citv of Fort Collins, Colorado
0
J
IH DESCRIPTION
S
o_
CDr'Aprox. Surface Elev.: 4984.5 ft.
3" ASPHALT
6" BASE COURSE
FTT L-Silty cand with
bed or ck fra=ent�Red/brown, moist, loose
FTT -1--Sandy lean _
7•0 clay with gavel
Black, moist, stiff
�o.
vrE t C:R ADET) (;RAVEL
wiTH SAND & COBRT FS
Tan brown. moist to wet, dense
a (Cobbles typical 12" =0
g
16.0
CT AYSTONE
Blue/black, moist, moderately hard
STT TCTONF/C'T AYSTONE
Blue/black, moist, hard
BOTTOM OF BORING
PROJECT
Iof1
M
v
}
2LL
C
Z
HF_
to
W
=
N
=
_
I fn
F-
C
2 Z
J
F
N
m
W
O
3
to
OW
JN
d
U
S
Q.
U
F O
H
Y LL.
U D: LL.
W W LL.
W
to
>
>-
W
0 _r
O
CCU
z I- to
3 z to
o
z
I—
rx
M m
E
a tL
m to o.
to a. Q.
4983.7
4979.0 5
4977.5 1
SW
1 ISSI
12"
7 1
15
2 IST
1
12"
1
181
111
2270
3 ISSI
12"
9
17
CL
4
SS
12"
11
5 ISSI
12"
11
12
6
SS
12"
27 1
71SS112-1311 11 1
4968.5 1
15
4966.5
20
25
—1 1 81 SS 1 12" 1 50 1 151 1 1
:F_I 9 1 SS 1 8.1500 1 14 1 1 1
550
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-20-96
WI — g 4' W.D. BORING 1111111 6-20-96
WL IrerraC0 n RIG CME-55 FOR AN DML
vL Water checked 1 day A.B. APPROVED NRS Ioa x 20965087
I CLIENT
Larimer Countv Facilities
srrE Block 31
City of Fort Collins, Colorat
L7
O
J
IU DESCRIPTION
Fi
cc
cc
0: Approx. Surface Elev.: 4980.5 ft.
0.3 3" ASPHALT
m 5" BASE COURSE
1.5 1 ETT T c:t.,,
LOG OF BORING No. 3
ARCHITECT I ENGINEER
PROJECT
'� cand with vel
ed/brown, moist, loose
R5.5 SANDY LEAN
C AY WITH GiAVEL
a�
a�
ed/tan, moist, medium
g WELL GRADED GRAVEL
WITH SAND R• COBBLES
Red/tan, moist to wet, dense
(Cobbles typical 8" max.)
a 12.5
WFATHFRFII ST_T_"T'$TONE/
14.0 C'T AYSTONE
Blue/black, moist, moderately hard
crr TCTnNFiOT.AYSTONE
Blue/black, moist, hard
29.7
Pr000sed Justice Center
1 of 1
SAMPLES
TESTS
C
Z
HH
v
}
a:Z\
K
to
C
Z Z
1C
W
j
t Cn
F=-
_i cn
F-
to
m
W
O
3
fn
ow
J to
d
U
r
d
U
H O
H
>- LL
U C Lt-
W W LL
W
W
O
Y
W
tLJ
O
MU
ZHfA
3KtA
O
O
Z
F-
M
MCC
r-
co-
O lA d
N 0-d
4979.0
4975.0 5-
10-
4968.0
4966.5
15
20
25
4950.8
1 SSI 12-1 6
2 ST 12"
3 1 SS 1 12"1 5
131 117 1 1180
-4GWI 41 SS 1 12" 1 44 1 121 1 1
5 1 SS 1 12"1 48 1 17
7
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
3ETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-20796
WL 6 8, W.D. �= 6.7' A.B BORING COMPLETED 6-20-96
,VI1 reraconRIGrC » FOREMAN DVQ
��L Water checked 1 day A.B. APPROVED NRS JOB # 20965087
ICLIENT
SITE
Larimer County Facilities
Block 31
of Fort Collins,
LOG OF BORING No. 1
ARCHITECT / ENGINEER
PROJECT
0
O
J
IH
DESCRIPTION
0-
G.
0
Approx.
Surface Elev.: 4984.0 ft.
0.4
5-1/2" ASPHALT
1.0
6" BASE COURSE
2•
FTT T sand with gravel
_ y
Red/brown, moist, medium dense
SANn_YT.EAN
CLAY NVITH GRAVEL
o
ty
6.5
Red, moist, stiff
GRAnFn GRAVEL
WELL
�TH CANT) & COBBLES
$
Tan brown, moist to wet, dense
(Cobbles typical 6" max.)
13.5
.W ATT1FRFn STL TSTONF/
15.0
CI AYSTONE
E::5=�
Blue/black, moist, moderately hard
CTT TCTONFICL AYSTONE
:9
Bluelblack, moist, hard
29
BORING
U.
(L
W
G
}
(N
U
N
7
tr
L
O
Z
d
>
F-
W
W
U
W
C
Z\
1-0
0-J
Nm
C
O
N
O
E
Cn
Z
W
YLL
mu
on.
MH
LL CD
U=LL
ZF(n
=Cna-
4983.6
SC
I
SS
12"
21
13
4983.0
4981.5
2
SS
12"
15
3
ST
12"
14
117
2430
CL
4
SS
12"
7
15
5
10
20
25
AGWI 5 1 SS 1 12"1 36 1 10 1 1 1
1of1
—I 17 I SS 1 12"1 50 1 15 I 1 J
q_— T 81 SS 1 8"15001 191 1 1
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
3ET11E-eN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-20-96
WL 7.0' W.D. 1 A.B., BOR
6.5' ING COMPL0-96
ETED 6-2
1 Derr acon RIG CME 55 FORF3IAN Dim
��ti Water checked 1 day A.B. APPROVED Ng$ JOB a 20965087
GENERAL NOTES
DRILLING & SAMPLING SYMBOLS:
SS
Split Spoon - 1%0 I.D., 2" O.D., unless otherwise noted
PS
Piston Sample
ST
Thin -Walled Tube - 2' O.D., Unless otherwise noted
F S
Wash Saailmple
FT
Fish Bit
PA
Power Auger
RB
Rock Bit
HA
DB
Hand Auger
Diamond Bit - 4", N, B
BS
BS
Bulk Sample
BulkPresSample
AS
Auger Sample
DC
r
Dutch Cone
HS
Hollow Stem Auger
WB
Wash Bore
Standard 'IN" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2 inch OD split spoon,
except where noted.
WATER LEVEL MEASUREMENT SYMBOLS: WS While Sampling
WL Water Level
WCI Wet Cave In BC While Drilling
DCI Dry Cave In R Before Casing Removal
AB After Boring ACR After Casing Removal
Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. In pervious
soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate deter-
minati,in of ground water levels is not possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION:
SO Classification is based on the Unified Soil Classification System and ASTM Designations D-2487 and D-2488.
Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; they :re described as:
boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200
sieve; they are described as: clays, if they are plastic, and silts if they are slightly plastic or non -plastic. Major con-
stituents may be added as modifiers and minor constituents may be added according to the relative proportions
based on grain size. In addition to gradation, coarse grained soils are defined on the basis of their relative in -place
density and fine grained soils do the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff
(CL); silty sand, trace gravel, medium dense (SM).
CONSISTENCY OF FINE-GRAINED SOILS:
Unconfined Compressive
Strength, Our psf
Consistency
< 500
Very Soft
500 - 1,000
Soft
1,001 - 2,000
Medium
2,001 - 4,000
Stiff
4,001 - 8,000
Very Stiff
8,001-16,000
Hard
>-16,000
Very Hard
RELATIVE PROPORTIONS OF SAND AND GRAVEL
Descriptive Term(s)
(of Components Also
Percent of
Present in Sample)
Dry Weight
Trace
< 15
With
15 - 29
Modifier
> 30
RELATIVE PROPORTIONS OF FINES
Descriptive Term(s)
(of Components Also
Percent of
Present in Sample)
Dry Weight
Trace
< 5
With
5 -12
Modifier
> 12
RELATIVE DENSITY OF COARSE -GRAINED SOILS:
N-Blowslft.
Relative Density
0.3
Very Loose
4.9
Loose
10.29
Medium Dense
30.49
Dense
50.80
Very Dense
80+
Extremely Dense
GRAIN SIZE TERMINOLOGY
Major Component
Of Sample Size Range
Boulders Over 12 in. (300mm)
Cobbles
Gravel
Sand
Silt or Clay
12in. to3in.
(300mm to 75mm)
3 in. to p4 sieve
(75mm to 4.75mm)
p4 to #200 sieve
(4.75mm to 0.075mm)
Passing #200 sieve
(0.075mm)
Form 108-6.85
Irerracon
APPENDIX D
BORING LOGS
2
Larimer County Justice Center limited Phase II ESA
Project No. 20965087
July 17, 1996
Page C2
Terracon
chain -of -custody procedures to TLI for chemical analyses. The borehole water sample
results are summarized in Table 2 in Appendix B.
Cleaning Operations
Sampling equipment, drilling equipment and the drill rig were cleaned with a high-
pressure, hot-water washer prior to entering the site and prior to leaving the site. The
sampling equipment was cleaned by hand between sampling episodes using soap and
water. Wash water from the cleaning operations was discharged on site.
Safety Protocol
The field work was conducted by Terracon personnel using modified Level "D" personal
protective procedures. Modified Level "D" personal protective procedures are designed to
protect the worker from common work place hazards and to reduce contact with potential
contaminants. Modified Level "D" personal protective equipment includes rubber gloves,
rubber boots and hard.hats.
n
Terracon
FIELD METHODS
Soil Borings
The soil borings were completed at the site on June 20 and 21, 1996. The approximate
locations of the soil borings are shown on Figure 1 in Appendix A. The drilling services
were performed by a three-man crew consisting of a field engineer, a driller and a driller's
helper.
Completion of Borings 1, 3, 7, 8 and 9 was performed with a truck -mounted CME-55 rotary
type drill. The borings were advanced with 3 1/4-inch hollow -stem augers. The augers
were advanced to depths of approximately 30 feet below the ground surface. Auger
cuttings were placed back in the boreholes and excess cuttings were removed from the
site.
Field logs of Borings 1, 3, 7, 8 and 9 were prepared by the Terracon field engineer. The
logs contain visual and tactual classifications of the materials encountered during drilling,
as well as the driller's interpretation of subsurface conditions based on drilling resistance
and difficulty.
Soil Sampling
Split -spoon sampling techniques were used to collect soil samples from Borings 1, 3, 7, 8
and 9. Soils encountered while drilling were screened on site for organic vapors with a
PID to aid in evaluating potential zones of petroleum hydrocarbon contamination. Soil
samples were collected at various intervals for ambient temperature headspace analysis
(ATHA). The ATHA procedure consisted of placing the soil samples in Ziplock bags such
that the bags were approximately one-third full. The sample was allowed to equilibrate
with the container headspace for approximately 15 minutes. The probe of the PID was
then used to pierce the bag and the maximum observed reading was recorded. ATHA
results are summarized in Table 1 in Appendix B. ATHA results are considered only a
qualitative field measurement of contamination and should not be interpreted as
quantitative analyses.
Borehole Water Sampling
Borehole water samples were collected from Borings 1, 3, 7 and 8 on June 20, 1996. The
samples were collected with disposable polyethylene bailers attached to nylon ropes. A
new bailer was used for sampling each borehole. The borehole water samples were
transferred into pre -cleaned sample containers and transported under standard Terracon
APPENDIX C
FIELD METHODS
TABLE 2
SUMMARY OF BOREHOLE WATER SAMPLE RESULTS
PROJECT NAME: Larimer County Justice Center Limited Phase II ESA
PROJECT LOCATION: Block 31, City of Fort Collins, Colorado
PROJECT NUMBER: 20965087
Total
Sample Sample Benzene Toluene Ethylbenzene
Xylenes
TVPH
Name Date (Ug/L) (Ng/L) (Vg/L)
(pg/L)
(mg/L)
Boring 1 6/20/96 <0.5 <0.5 <0.5
<0.5
<0.5
Boring 3 6120/96 <0.5 <0.5 <0.5
<0.5
<0.5
Boring 7 6/20/96 <0.5 <0.5 0.8
1.6
<0.5
Boring 8 6/20/96 <0.5 <0.5 <0.5
<0.5
<0.5
Groundwater
Standards 5. 1,000. 680.
10,000.
NR
NOTES:
1. Sample Locations are shown on Figure 1 in Appendb(A.
2. TVPH = Total Volatile Petroleum Hydrocarbons
3. NR = Not Regulated
4. The Colorado Groundwater Standards are published in "Basic Standards for Groundwater 3.11.0*
effective March, 1995.
1 rerracon
Form 101-1.87
APPENDIX B
TABLES
r
BM. NORTH BONNET
BOLT OF FIRE HYDRANT
ELEVATION 4990.10—�s------------ HOWES STREET
—-_--_ ---_ ----
WET�
No. 9 No_6 No.I
I I
� I
l BLOCK 31 e
101 vl
IZ o
No.7 -- - - ml
IZ - -- - --------- -- ml
--- —� DI
Imr--------------- ---- NO=` zl
IcI �ml
Iml I I
I
No. 1 9 No.S I
I I I
I I A No. S
I
I � �
No
MASON STREET
L-------------------------
FIGURE 1: SITE PLAN
LARTMER COUNTY JUSTICE CENTER
FORM' COLLINS, COLORADO
TCW TNC. PROJECT No. 20965087
SCALE 1" = 100'
1.1 rerrac®n
CONsuvwrfS WESTERN. INC.
F.►11'IItE DIVISION
APPENDIX A
FIGURES
Larimer County Justice Center Limited Phase II ESA Terracon
Project Number 20965087
July 17, 1996
Page 5
implied, are intended or made. In the event that any changes in the nature or location of
suspected sources of contamination as outlined in this report are observed, the
conclusions and recommendations contained in this report shall not be valid unless these
changes are reviewed and the opinions of this report are modified and verified in writing
by Terracon.
u
1
Larimer County Justice Center Limited Phase 11 ESA Terracon
Project Number 20965087
July 17, 1996
Page 4
1. Organic vapor readings were observed to vary from not observed in the parts per
million (ppm) range to eight (8) ppm in the soil samples collected from Borings 3, 7,
8 and 9 while PID readings were not observed in the ppm range in the soil samples
collected from Boring 1.
2. Groundwater was observed at the site at depths of approximately 6.5 to 10.8 feet
below grade. Based on local topography and nearby surface water bodies, the
groundwater flow direction near the subject site is estimated to be in an easterly to
northeasterly direction.
3. Concentrations of BTEX and TVPH were not observed above or were observed
near the laboratory detection limits in the borehole water samples collected from
the site. The concentrations of BTEX observed in the borehole water samples
collected from Borings 1, 3, 7 and 8 were below the Colorado Groundwater
Standards.
Based upon available information, it does not appear that significant petroleum
hydrocarbon contamination has impacted the subject site. Additional observation and/or
testing of soil and groundwater may be warranted during construction if excavation of soil
and/or dewatering of groundwater is required as pan: of construction for the proposed
Justice Center.
7. GENERAL COMMENTS
Terracon has performed a Limited Phase II Environmental Site Assessment in general
accordance with the scope and limitations of the proposed scope of services dated April
25, 1996. The analyses and opinions expressed in this report are based upon data
obtained from the soil borings completed at the indicated locations along with other
information described in this report. This report does not reflect any variations in
subsurface stratigraphy, geohydrology, or contaminant distribution which may occur
across the site. Actual subsurface conditions may vary and may not become evident
without further exploration. Due to the dynamic nature of groundwater flow and
contaminant migration, subsurface conditions will vary with time.
This report has been prepared for the exclusive use of Larimer County for specific
application to the subject property and has been prepared in accordance with generally
accepted geo-environmental engineering practices. No warranties, either express or
Larimer County Justice Center Limited Phase II ESA Terracon
Project Number 20965087
July 17, 1996
Page 3
precipitation and recharge or other conditions not evident at the time of the field
exploration.
5. CONTAMINANT CHARACTERISTICS
Borehole water samples were collected from Borings 1, 3, 7 and 8 and transported under
standard Terracon chain -of -custody procedures to Technology Laboratory, Inc. (TLI) in
Fort Collins, Colorado for chemical analyses. The borehole water samples from the four
(4) soil borings were analyzed for benzene, toluene, ethylbenzene and xylenes (BTEX)
and total volatile petroleum hydrocarbons (TVPH) by methods EPA-8020 and EPA -
Modified 8015, respectively. Analytical results for the borehole water samples are
summarized in Table 2 in Appendix B. Laboratory reports prepared by TLI are enclosed in
Appendix E of this report.
As seen from Table 2, concentrations of BTEX and TVPH were not observed above their
respective laboratory detection limits of 0.5 micrograms per liter (µg/L) and 0.5 milligrams
per liter (mg/L) in the borehole water samples collected from Borings 1, 3, 7 and 8 with the
exception of ethylbenzene and xylenes which were observed at concentrations of 0.8 and
1.6 µg/L in the borehole water sample collected from Boring 7. The Colorado
Groundwater Standards for BTEX are also summarized in Table 2. As seen from Table 2,
the standards for BTEX are 5; 1,000; 680 and 10,000 µg/L, respectively. Those standards
are the statewide interim organic pollutant standards published in "The Basic Standards
for Ground Water 3.11.0 (5 CCR 1002-8)." TVPH concentrations in groundwater are not
regulated in Colorado at this time. As seen from Table 2, the concentrations of BTEX
observed in the borehole water samples collected from _Borings 1, 3, 7 and 8 were below
the Colorado Groundwater Standards. It should be noted that the analytical results are
considered preliminary in nature since the borehole water samples were not collected from
cased and developed groundwater monitoring wells.
6. SUMMARY AND CONCLUSIONS
Terracon has completed a Limited Phase II ESA in general accordance with the scope and
limitations of Terracon's proposed scope of services dated April 25, 1996 of the property
located in Block 31 of the City of Fort Collins, Colorado. The following summary is made
based on information obtained during the completion of the assessment.
u
4
Larimer County Justice Center Limited Phase II ESA
Project Number 20965087
July 17,1996
Page 2
Terracon
observed in the ppm range in the soil samples collected from Boring 1. ATHA is a
qualitative indicator of volatile organic contamination and should not be construed as a
quantitative measure.
3. SUBSURFACE SOILS
Descriptions of the soils encountered in Borings 1, 3, 7, 8 and 9 are provided on the
boring logs which are included in Appendix D. Those descriptions are in general
accordance with the General Notes also included in Appendix D. The stratification
boundaries shown on the attached boring logs represent the approximate locations of
changes in soil types; in -situ, the transition of materials may be gradual. The final boring
logs included in this report represent an interpretation of the field logs. Please refer to the
boring logs in Appendix D for a graphical representation of the materials encountered at
the site.
Based on the results of the field borings, the subsurface conditions can be generalized as
follows. Approximately three (3) to five (5) inches of asphalt was encountered at the
surface of Borings 1, 3, 7, 8 and 9 and was underlain by five (5) to six (6) inches of
aggregate base course. Fill, consisting of varying amounts of sand, silt, clay and gravel,
was encountered beneath the base course in those borings. The fill extended to depths of
approximately 1.5 to 5.5 feet below grade. The fill material encountered in Borings 1, 3, 8
and 9 was underlain by sandy lean clay with varying amounts of gravel to depths of
approximately 5.5 to 11.5 feet below grade. The sandy lean clay encountered in Borings
1, 3, 8 and 9, as well as the fill encountered in Boring 7, was underlain by gravel with
varying amounts of sand and cobbles to depths of approximately 12.5 to 18 feet below
grade. The gravel layer was underlain by siltstone/claystone bedrock which extended to
the bottom of the borings.
4. GROUNDWATER OBSERVATIONS
Groundwater was observed in Borings 1, 3, 7, 8 and 9 at depths of approximately 6.5 to
10.8 feet below grade while drilling and one (1) to three (3) days after drilling. Based on
local topography and nearby surface water bodies, the groundwater flow direction near the
subject site is estimated to be in an easterly to northeasterly direction. Installation and
development of groundwater monitoring wells would be required to obtain stabilized
groundwater elevations and to estimate a piezometric surface for the site. It should be
noted that local geohydrologic conditions may change due to variations in stratigraphy,
LIMITED PHASE II ENVIRONMENTAL SITE ASSESSMENT
LARIMER COUNTY JUSTICE CENTER
BLOCK 31
CITY OF FORT COLLINS, COLORADO
Project Number 20965087
Date: July 17, 1996
1. INTRODUCTION
Terracon Consultants Western, Inc. (Terracon) has completed a Limited Phase II
Environmental Site Assessment (Limited Phase II ESA) of the proposed Justice Center
located in Block 31 in the City of Fort Collins, Colorado. This work was performed in
general accordance with Terracon's proposal dated April 25, 1996. The site assessment
included the following tasks:
Collection of borehole water samples from four (4) soil borings completed on site;
and
• Chemical analysis of the borehole water samples.
The purpose of this Limited Phase II ESA was toobtain information regarding possible
groundwater contamination beneath the subject site. This Limited Phase II ESA was
completed in conjunction with a geotechnical exploration of the subject site. The results of
the geotechnical exploration were summarized in a report prepared by Terracon dated July
8, 1996.
2. SUBSURFACE EXPLORATION
The approximate locations of ten (10) soil borings, 1 through 10, completed on the subject
site on June 20 and 21, 1996 are shown on Figure 1 in Appendix A. Borings 1, 3, 7, 8 and
9 were completed for geotechnical and environmental purposes while Borings 2, 4, 5, 6
and 10 were completed for geotechnical purposes only. The methods used to perform the
field sampling operations are presented in Appendix C of this report.
Soil samples were collected for ambient temperature headspace analyses (ATHA) at
various depths in Borings 1, 3, 7, 8 and 9. The ATHA procedure is described in Appendix
C while the ATHA results for each soil sample are summarized in Table 1 in Appendix B.
As seen from Table 1, photoionization detector (PID) readings were observed to vary from
not observed in the parts per million (ppm) range to eight (8) ppm as organic vapor in air in
the soil samples collected from Borings 3, 7, 8 and 9 while PID readings were not
J
' TABLE OF CONTENTS
Page
1.
INTRODUCTION...........................................................................................................1
2.
SUBSURFACE EXPLORATION....................................................................................1
SOILS
3.
SUBSURFACE ..................................................................................................2
4.
GROUNDWATER OBSERVATIONS.............................................................................2
5.
CONTAMINANT CHARACTERISTICS...........................................................................3
6.
SUMMARY AND CONCLUSIONS.................................................................................
3
7.
GENERAL COMMENTS................................................................................................4
APPENDICES
APPENDIX A - Figures
APPENDIX B - Tables
APPENDIX C - Field Methods
APPENDIX D - Boring Logs
APPENDIX E - Laborafory Reports
V
1
Larimer County Justice Center Limited Phase II ESA Terracon
Project Number 20965087
July 17, 1996
Page 2
We appreciate the opportunity to be of service to you on this project. If there are any
questions concerning this report, or if we may be of further assistance, please do not
hesitate to contact us.
Sincerely,
TERRACON CONSULTANTS WESTERN, INC.
;tea. -'.'
Scott A. Rutherford, P.E.
Colorado No. 7
eil R. e
Senior Engineering Geologist
NRS/SAR:sar2
(FTC)N:\PROJECTS\E LI FTC\20965087\60717E SA.RPT
•Y�
Irerracon
CONSULTANTS WESTERN, INC.
EMPIRE DIVISION
P.O. Box 503.301 N. Howes
Fort Collins. Colorado 80522
(970)484.0359 Fax (970) 484-0454
Larry G. O'Dell. P.E.
Neil R. Sherrod. C.P.G.
July 17, 1996
Mr. Dick Anderson
Larimer County Facilities
P.O. Box 1190
Fort Collins, Colorado 80522
Re: Limited Phase II Environmental Site Assessment
Larimer County Justice Center
Block 31
City of Fort Collins, Colorado
Project Number 20965087
Dear Mr. Anderson:
Terracon Consultants Western, Inc. (Terracon) has completed a Limited Phase II
Environmental Site Assessment for the above -referenced property in Fort Collins,
Colorado. The assessment was completed in general accordance with our proposal dated
April 25, 1996. Our observations concerning the environmental conditions at the site are
contained in this report and the attached appendices.
Petroleum hydrocarbons were not observed above the laboratory detection limits or were
observed near the laboratory detection limits in the borehole water samples collected from
the site. Based upon available information, it does not appear that significant petroleum
hydrocarbon contamination has impacted the subject site from previous uses of the site or
adjacent properties. Please read the enclosed report for more details.
Offices of The Terracon Companies, Inc. Geotechnical. Environmental and Materials Engineers
Arizona ■ Arkansas ■ Colorado ■ Idaho ■ Illinois ■ Iowa ■ Kansas ■ Minnesota
Missoun ■ Montana ■ Nebraska ■ Nevada ■ Oklahoma ■ Texas ■ Utah ■ Wyoming
QUALITY ENGINEERING SINCE 1965
LIMITED PHASE 11 ENVIRONMENTAL SITE ASSESSMENT
LARIMER COUNTY JUSTICE CENTER
BLOCK 31
CITY OF FORT COLLINS, COLORADO
Project Number 20965087
July 17, 1996
Prepared for:
LARIMER COUNTY FACILITIES
FORT COLLINS, COLORADO
Prepared by: ,
TERRACON CONSULTANTS WESTERN, INC. 0
Fort Collins, Colorado /L�
SD
c �
V
1•
lferracon
Form 101-1-87