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Home My WebLink AboutLARIMER COUNTY COURTHOUSE - FDP - 37-98B - SUBMITTAL DOCUMENTS - ROUND 1 - ENVIRONMENTAL REPORT1 EL - -.NU-_ — -J Y __ _1fU_ _ _ 1 V. , 11N CENTRE FOR ADVANCED TECIINOLOCY 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. Dale Received: 6/24/96 301 North Howes - Dale Analy-zcd: 6/26/96 Fort Collins, Colorado 8621 Project No.: 20%5087 (% Recovery) Fluorobenzenc Bromolluorobcnzcnc Lab ID Samnlc ID Limits (75-125%4) Limits (75-125%) 96280-1 Boring 1 106 97 98 96280-2 Boring 3 105 96280-3 Boring 7 105 102 96280-4 Boring 8 105 98 TECHNOLOGY LABORATORY, INC. Page 2 of 2 I G\ IVY 1 � •\lV• • • CENTRE FOR ADVANCED TECHNOLOGY 2401 Research Boulevard, Suite 204 Fort Collins, Colorado 80526 (970)490-1414 VOLATILE ORGANICS WATER ANALYSIS REPORT TERRACON CONSULTANTS INC., EMPIRE DIV. Date Received: 6/24/96 Date Analyzed: 6/26/96 301 North Howes Project No.: 20965087 Fort Collins, Colorado 80521 Date Benzene Toluene Ethylbcnzcnc Xylcncs TVPH-Purgcablc Lab ID Sample ID Sampled jg/l, ttG/L tt" ImIL 111g/1' 96280-1 Boring 1 6/20/96 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 96280-2 Boring 3 6/20/96 <0.5 <0.5 <0.5 <0.5 0.8 1.6 <0.5 96280-3 Boring 7 96280-4 Boring 8 6/20/96 6/20/96 <0.5 <0.5 <0.5 <0.5 <0.5 TECINOLOGY LABORATORY, INC. Page 1 of 2 BTEX Method: EPA-8020 TVPH-Purgeable Method: EPA -Modified 8015 APPENDIX E LABORATORY REPORTS ICLIENT SITE Larimer County Facilities Block 31 Fort Collins, to a J DESCRIPTION H x a Crcc Approx. Surface Elev.: 4987.5 ft. 0.3 4" ASPHALT 0.8 5" BASE COURSE ' FTT T _ tyclayey sand 4.0 Brown, moist, loose , SANDY LEAN e7� CLAY WITH GRAVEL �j Red/tan, moist, medium LOG OF BORING No. 9 ARCHITECT / ENGINEER PROJECT WET L GRADED GRAVEL �aWITH SAND & COBBLES A Tan/brown, wet, dense 4 (Cobbles typical 8" max.) g 18.0 WEATHERET) ST TSTONE/ 20.0 OT AYSTONE Blue,fblack, moist, moderately hard -� SIT TSTONE/CL AYSTONE Bluelblack, moist, hard 29.5 BORING v a- Ul c o N U to M z CO n z a >. I- I w U W o: t= z LL F_c a-i Unto H o r_ w >.L� MU cn_ o LL CD UKLL. zt-tn m(no- 4987.2 4986.7 SM 1 SS 12" 7 12 C 2 SS 12" 7 4983.5 -SC3 ST 12" 16 111 2960 CL 4 SS 12" 5 14 5 5 SS l2" 5 6. ST 12" 11 118 13450 7 SS 12" 5 15 110 15TI 8ISSI12"I 32 I 22I 4969.5 4967.5 20 495 25 loft 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 HT- Q 10.8' W�D• = 1U.5' A B I reff acon RIGE RING COMPLETED FOR&6� _96 WL CM-55 DML WL I Water checked 3 days A.B. APPROVED NRS JOB x 20965087 go LOG OF BORING No. 8 I CLIENT County Facilities ENGINEER Larimer Conty Facilities srrE DI k 31 PROJECT oc City of Fort Collins, Colorado- 0 J H DESCRIPTION o_ ' C Approx. Surface Elev.: 4986.: ft. `• 0.4 5" ASPHALT 0•9 6" BASE COURSE 2.5 ETT T _ ' v sand with onvel Brown/black, moist, medium dense SANDY LEAN CLAY Red, moist, medium 6.5 .a ¢e WELL GRADED GRAVEL WITH SAND & COBBLES__ $ Brown, moist to wet, dense (Cobbles typical 12" max.) a \� WEATHERED Si_ .TCTT�/ 16.5 CLAY—�E Tan/gray, moist, moderately hard STT TSTONE/CL.AYSTONE �— Tan/gray, moist, hard 29. BOTTOM OF BORLNG 1of1 r. \ E G O H H O F 03 LL H w H Z a. z\ W Cl) to K W O LLi CD O~ = w 7 fn F O zz HHZ H w In W O 3 to ow mcnH a U E a U �_o H >-w UMw 0(Cw w N o> w o"J O Q:U zHtn HJ o z f- M tnm E oa ocna Jam 4986.1 4985.6 5- 4980.0 i 10' 4972.0 15 4970.0 20 25 4957.1 1 SSI 12-1 15 2 ST I 12" 3 SS 1 12"1 5 27 1 102 1 1410 23/3/41 17 -aGWI 41 SS 1 12"1 41 1 91 1 1 5 I SSI 12" 32 1 25 6 SS 12-1 50 1 17 7 I SS I 8" 50/.7 I 16 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 %vL g 9.3' W.D. = 9.39 A•B• BORING COMPLETED 6-21-96 %v Irerraron RIG CMI-55 FOREJtAN DM1. WL Water checked 3 days A.B. APPROVED FRS JOB ,t 20965087 - I CLIENT Larimer County Facilities SITE Block 31 Citv of Fort Collins, Colorado L� O •J IU DESCRIPTION 2 ti r(DApprox. Surface Elev.: 4984.5 ft. SPHALT ASE COURSE T _ ' tysand with nck fragments fbrown, moist, loose _- FTLL-Sandy lean 7.0 clay with gravel Black, moist, stiff WELL rR ADED GRAVEL a WTTH CANT) & COBBLES e. e Tan brown, moist to wet, dense (Cobbles typical 12" mar.) 16.0 Ci 4YSTONE Bluelblack. moist, CTT TSTONF/C LAYSIMM Bluefblack, moist, hard LOG OF BORING No. 7 ARCHITECT I ENGINEER PROJECT hard BOTTOM OF BORING loft d Justice Center SAMPLES TESTS W d F}• W > O U o. LLMW Z\ I (n 3 !-O Nib F- to N r- W O rtL W. U- 0 ZZ OW Ucru. ZNd JN Jto WWU. cn WCLa. ffProvos cc 4984.2 4983.7 SWI 1 IS 12" 7 15 2 ST 12" 18 111 2270 3 SS 12" 9 17 4979.0 5 CL 4 SS —12 " 11 4977.5 5 SS 12" I1 12 6 SS 12" 27 10- 4968.5 1 15 4966.5 20 25 7 1 SS 1 12" 1 31 1 11 -4 1 81 SS 1 12"1 50 1 151 1 1 :F-1 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 TRANSITIO_N'MAY BE GRADUAL. WATER LEVEL OBSERVATIONS BORING STARTED 6-20-96 WL Irerracon`--' 8.4' W.D. i 8.3' A.B. BORING CONIPLETED 6-20-96 RIG CME-55 FOREMAN DML Water checked 1 day A.B. APPROVED NR$ JOB a 20965087 WL ICLIENT srrE Larimer County Facilities Block 31 Fort Collins, LOG OF BORING No. 3 ARcxrrECT / EvcINEER PROJECT Lo 0 IH DESCRIPTION a. d 0 Approx. Surface Elev.: 4980.5 ft. 0.3 3" ASPHALT 5" BASE COURSE m 1.5 FTT 1 -Silty clayey sand with °ravel ed/brown, moist, loose 5.5 SANDY LFAN CLAY WTTH GRAVEL ed/tan, moist, medium a.� WELL GRADFD GRAVE wTTH SAND ,G CbBBLES Red/tan, moist to wet, dense (Cobbles typical 8" max.) 12.5 WEATHERED STT.TSTONF/ 14.0 C AY�NE Blue/black, moist, moderately hard S.11 TCTONFICLAYSTONE Bluelblack, moist, hard 29.7 X IofI Proposed Justice Center SAMPLES I TESTS tY W co r_ O z W D- > f- � W � O U W M zca \ t N 3 I-O dJ tnm � I- N H O E >- z W 0 >-LL KU 0a H� LL 0 zz ow UCXLL ZF-fA �tno. z M JN JN WWLL 3Mcn tnaa = F d W 0 >. Ln N U w 0 4980.2 4979 0 SM 1 SS 12" 6 17 SC 2 ST 12" 13 117 1180 CL 3 ISSI IL-1I 13 4975 0 1 5 4950.8 10 15 25 -4GWI 41 SS 1 12" 1 44 1 121 1 1 4 1 5 1 SS 1 12"1 48 1 17 1 1 1 7-150/.61 13 1 1 1400 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 WL 2 6.8' W D I= 6.T A B BORING COMPLETED 6-20-96 WL Irerracon RIG CME-55 FOREMAN DNIL ��_L Water checked 1 day A.B. APPROVED Ngg Jos 20965037 I CLIENT Larimer Countv Facilities SITE Block 31 City of Fort Collins, Colorado LOG OF BORING No. 1 ARCHITECT / ENGINEER PROJECT r, O J IH DESCRIPTION CL 0 Approx. Surface Elev.: 4984.0 ft. 0.4 5-1/2" ASPHALT 1.0 6" BASE COURSE 2.5 FILL and mirk gravel -Silty Red/brown. moist, medium dense a ( A SANDY T.EAN rT AY wTTN GRAVEL tg 6.5 Red, moist, stiff WELL GRADED GRAVEL a WITH SAND Rr COBBLES a Tan/brown, moist to wet, dense (Cobbles typical 6" max.) e+ 13.5 5.A ED STT'TSTONE/ 0 15.0 WFTHI: rT AYSTONE Blue/black. moist, moderately hard SIT TCTONr/rT AY.STONE E:EE Blue/black, moist, hard 29.5 BOTTOM OF Pro osed Justice Center SAMPLES TESTS 0: z a W w U W Z\ F_c W0 M :3 IN-+ E Z w �U_ cna. C3 MH U-0 UMU_ mcna- ^ v a C3 Jo } w U n 4983.E SCI 1 ISSI 12" 21 13 4983.0 4981.5 2 SS 12" 15 3 ST 12" 14 117 2430 if 4 SS 12" 7 15 5 4954.5 10 20 25 —IGWI 5 1 SS 1 12" 1 36 1 101 1 1 1of1 —I 1 71 SS 1 12" 1 50 1 151 1 1 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 6-20-96 WI- 7.0' W�D• T- 6.5' A.B.BORING COMPLETED 6-20-96 �� , Irerracon RIG CME-55 FOREaNIAN D W`L Water checked 1 day A.B. APPROVED NRS JOB a 20965087 GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS : Split Spoon - 1%" I.D., 2" O.D., unless otherwise noted PS : Piston Sample ST : Thin -Walled Tube -2" O.D., Unless otherwise noted FT : Fish Tail gple it PA Power Auger RB : Rock Bit HA : DB : Hand Auger Diamond Bit - 4% N, B BS : Bulk Sample AS : Auger Sample PM : DC : Pressuremeter Dutch Cone HS : Hollow Stem Auger WB : Wash Bore Standard "N" 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 WD - While Drilling WCI : Wet Cave In BCR : Before Casing Removal DCI Dry Cave In 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: Sol 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 bn 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 Sariiple Size Range Boulders Over 12 in. (300mm) Cobbles Gravel Sand Silt or Clay 12 in. to 3 in. (300mm to 75mm) 3 in. to N4 sieve (75mm to 4.75mm) #4 to #200 sieve (4.75mm to 0.075mm) Passing k200 sieve (0.075mm) Form 108-6.85 1 ferracon APPENDIX D BORING LOGS Larimer County Justice Center Limited Phase It ESA Terracon Project No. 20965087 July 17, 1996 Page C2 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. FIELD METHODS Soil Borings Terracon 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 I 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 I PROJECT NUMBER: 20965087 Total Sample Sample Benzene Toluene Ethylbenzene Xylenes TVPH I Name Date (ug/L) (pg/L) (ug/L) (Ng/L) (mg/L) Boring 1 6/20/96 <0.5 <0.5 <0.5 <0.5 <0.5 Boring 3 6.120/96 <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 Appendix 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. Herracon Form 101-1.87 TABLE 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 ND Boring 1 6/20/96 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 6/20196 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 6/21/96 4 to 5 1 Borino 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 S. 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 APPENDIX B TABLES I BM. NORTH BONNET BOLT OF FIRE HYDRANT ELEVATION 4990.1�-----_--- _-- HOWES SSTREET -- _--_ ---_ -- _— WETR- No.9 No_6 No. I � I I � I BLOCK 31 � I 13i �rl lo' v Ic I z o In No.7 _ __ __ �I Iz _-_---------------- --- ml jcr-------------- -- ----- -N��, m Icy Iml Im I I I I �No.1 BNOS I I I No.8 I � � I No.36-j L------------MASON STREET -- FIGURE 1: SITE PLAN LARIMER COUNTY JUSTICE CENTER FORT COLLINS, COLORADO TCW INC'. PROJECT No. 20965087 SCALE 1" = 100 11rerrac®n CONSIIITAN'I'S MES'1'EI(N. INC. UPIRE DIVISION -- 5 APPENDIX A FIGURES Larimer County Justice Center Limited Phase 11 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. Larimer County Justice Center Limited Phase II 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 part 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 n Larimer County Justice Center Limited Phase II ESA Project Number 20965087 July 17, 1996 Page 3 Terracon 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 pg/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. Larimer County Justice Center Limited Phase 11 ESA Terracon Project Number 20965087 July 17, 1996 Page 2 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. a 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, M 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 to obtain 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 TABLE OF CONTENTS Paae 1. INTRODUCTION...........................................................................................................1 2. SUBSURFACE EXPLORATION....................................................................................1 3. SUBSURFACE SOILS....................................................................................................2 4. GROUNDWATER OBSERVATIONS.............................................................................2 5. CONTAMINANT CHARACTERISTICS...........................................................................3 6. SUMMARY AND CONCLUSIONS.................................................................................3 COMMENTS 7. GENERAL ................................................................................................4 APPENDICES APPENDIX A - Figures APPENDIX B - Tables APPENDIX C - Field Methods APPENDIX D - Boring Logs APPENDIX E - Laborafory Reports 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. IL4Q . �z'� `I emu. Scott A. Rutherford, P.E. `"(.�/ Color o No. 7 ell R. a \�o�� `�E,aTE Senior Engineering Geologist #o�h 2575 B'"9 NRS/SAR:sar2 •-•"' J (FTC)N:\PROJECTSIELIFTC\20965087\60717ESA.RPT 9'^:o�PgR. gHEP?� fi 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 Anzona ■ Arkansas ■ Colorado ■ Idaho ■ Illinois ■ Iowa ■ Kansas ■ Minnesota Missoun ■ Montana ■ Nebraska ■ Nevada ■ Oklahoma ■ Texas ■ Utah ■ Wyoming QUALITY ENGINEERING SINCE 1965 C C 1? t c i+ J,2I r F G E (�) LIMITED PHASE II 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.a �, Fort Collins, Colorado a-�/ C3 a/ (o� Irerracon Form 101-1-87