Loading...
HomeMy WebLinkAboutWork Plans for Site Assessment. - 1997 and 200546 SECOR WwW,secorcom INTERNATIONAL_ 11085 Knott Avenue Suite B 0 R INCORPORATED Cypiess, CA 90630 Tel: 714.379.3366 Fax: 714 379.3375 October 17, 2005 SECOR Job No. 14CP.86293.07.1424 Mr. Corey Walsh Regional Water Quality Control Board Central Coast Region 895 Aerovista Place, Suite 101 San Luis Obispo, California 93401-7906 Re. Interim Remedial Action Plan for Dewatering of Groundwater during Underground Storage Tank System Removal 76 Service Station 6293 363 Santa Rosa Street Sari Luis Obispo, California Dear Mr. Walsh: At the request of ConocoPhillips Company (CPC), SECOR International Incorporated (SECOR) has prepared this Interim Remedial Action Plan (IRAP) proposing dewatering of potential petroleum hydrocarbon impacted groundwater during underground storage tank (UST) system removal activities to be performed at the referenced site (Figure 1). This IRAP includes a brief discussion of site background, previous investigations, subsurface conditions, proposed scope of work., and schedule. SITE BACKGROUND The site is an operating 76 Service Station located at the southern corner of the intersection of Santa Rosa Street and Montalban Street in San Luis Obispo, California (Figure 1). The facility currently includes two 12,000-gallon underground fuel storage tanks (USTs) located in the northern portion of the site, and two product dispenser islands located in the northeastern portion of the site. The site configuration is shown on Figure 2. J PREVIOUS INVESTIGATIONS In February 1997, the underground product piping was replaced at the site. In September 1997, IT Corporation (IT) drilled seven exploratory borings, designated B-1 through B-7. Borings B-1 and B-4 were converted to groundwater monitoring wells MW-1 and MW-4, respectively. Interim Remedial Action Plan Proposing Groundwater Dewatering During Underground Storage Tank System Removal 76 Service Station 6293 October 17, 2005 Page 2 In October 1998, IT installed well MW-5 in the northeastern area of the site. In May 2003, SECOR installed offsite wells MW-7 and MW-8. SECOR was unable to install well MW-6 during the May 2003 field event due to delays in the encroachment permitting process. SECOR remobilized to the site in July 2003 to install. MW-6 in the left turn lane of the northwest intersection of Santa Rosa Street and Montalban Street. Wells MW-6 through MW-8 were installed to a depth of 15 feet below ground surface (bgs). Total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX), and methyl tertiary butyl ether (MTBE) were not detected above laboratory reporting limits in samples collected from the borings for wells MW-7 and MW-8. Total petroleum hydrocarbons as diesel (TPHd) was reported in soil samples collected from MW-6 at a maximum concentration of 19 milligrams per kilogram (mg/kg) (5.5 feet bgs). In July 2003, Morrow Surveying (Morrow), of West Sacramento, California surveyed wells l\AW-1 and MW-4 through MVV-8 to coordinate groundwater elevations with the wells at the adjacent Chevron and Shell sites. Between November 8 and 10, 2004, SECOR field staff supervised S&G Drilling during the installation of three groundwater monitoring wells (MW-9, MW-10, and MW-11) in order to delineate the lateral extent of the dissolved phase plume in the southlsoutheast direction at the site. In addition, in order to expedite remediation of the dissolved phase hydrocarbons at the site, SECOR also supervised the installation of three sparge wells (SP-1 through SP-3). SENSITIVE RECEPTORS According to the State Water resources Control Board Geotracker data base, no wells exist within "/-mile of this site. SECOR contracted Environmental Data Resources to search databases of existing wells within a one mile of the site. According to EDR, thirteen wells exist within the search radius. A cluster of wells are located approximately 1/2-mile southeast (cross gradient) of the site. The nearest known water well is approximately /4-mile southeast of the site. The current well status is unknown. SECOR personnel visited the creek on April 28th 2005 and observed that the creel; was approximately 300 feet to the west of the site and approximate 35 to 45 feet below grade with steep banks. The creel, was flawing at the time of the site visit.. SUBSURFACE CONDITIONS Sediments beneath the site consist predominantly of silt, sand, and gravel to a maximum depth of 14 feet bgs. Shale and weathered shale begins at depths ranging from 4 to 14 feet bgs and continues to the maximum depth explored (26 feet bgs). During the Second Quarter 2005 groundwater sampling event, groundwater was measured in on and off -site wells at depths ranging between approximately 1.98 and 18.79 feet bgs. In regards to on site wells, groundwater depths were measured between 2.01 feet bgs (MW-1) and 18.79 feet bgs (MW-10). Groundwater beneath the site typically flows to the north. The regional groundwater flow direction, shown by coordinated monitoring data since 2003, is generally to the south/southwest. -1 P:/conocaPhillips/Project Folders/6293/Work Plans/TRAP UST Overexcavation Dewatering 10.05 SECOR Interim Remedial Action Plan Proposing Groundwater Dewatering During Underground Storage Tank System Removal 76 Service Station 6293 October 17, 2005 Page 3 Tertiary butyl alcohol (TBA) has been consistently detected in groundwater samples collected from on -site wells MW-1, MW-4, and MW-5 since TBA analysis was initiated in April 2001. Historical TBA concentrations peaked in 2001 and have been declining since. The maximum reported TBA concentration during the Second Quarter 2005 sampling event was 15,000 micrograms per liter (ug/1) in MW-4. PROPOSED SCOPE OF WORK During the removal of the UST system components (gasoline and waste oil USTS, dispensers and product piping), SECOR will be on -site supervising the excavation of soil and dewatering activities in the vicinity of the UST cavities at the location shown on Figure 2. Dewatering of the UST cavities is required during the removal of the gasoline USTs and potentially the waste oil UST. Work performed by SECOR personnel during UST removal, soil excavation and UST cavity dewatering will be performed in accordance with this TRAP and the Field and Laboratory Procedures provided in Attachment A. The specific scope of work is discussed below: Health and Safety Plan. As required by the Occupational Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910.120), and by California Occupational Health and Safety Administration (Cal -OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CDR Title 8, Section 5192), SECOR has prepared a site -specific Health and Safety Plan (HASP) for use by SECOR personnel. SECOR Field staff will review the HASP before beginning field operations at the site. SECOR personnel will also incorporate the CPC site demolition contractor into the safety tail gate meetings. Dewatering of Groundwater. Due to shallow groundwater at the site, the UST cavity will require dewatering during UST removal activities. The necessary amount of groundwater will be dewatered from the UST excavation and temporarily stored on -site in a 20,000-gallon Baker water storage tank: pending analytical data. The amount of groundwater removed is dependant upon the UST removal activities to insure a safe work environment. It is anticipated that up to approximately 15,000 gallons of groundwater may be extracted during the UST removal activities. Soil Excavation. During UST removal activities, petroleum impacted soil may be encountered in the areas surrounding the UST cavities, piping runs and dispenser islands. During removal activities, impacted soil may be excavated in an effort to remove secondary sources for groundwater impact. The amount of soil excavation is dependant upon the areas of impact. If soil impact is noted to be significant as determined by field monitoring with a photo -ionization detector, it is anticipated that soil excavation will be performed as a remedial alternative. Up to approximately 500 cubic yards of impacted soil may be excavated for removal and disposal. Soil and Groundwater Sample Collection and Analysis. Following the soil excavation and groundwater dewatering activities, SECOR will collect -J P:/ConocoPhiIli ps/Project Folders/6293/Work Plans/TRAP UST Overexcavation Dewatering 10.05 SECOR Interim Remedial Action Plan Proposing Groundwater Dewatering During Underground Storage Tank System Removal 76 Service Station 6293 October 17, 2005 Page 4 the necessary soil samples from the excavation sidewalls, if obtainable, and water samples from the UST cavities and the on site Baker TM storage tank, Soil and groundwater samples collected from the gasoline UST cavity will be submitted for laboratory analyses for TPHd using EPA Method 8015M, TPHg, BTEX and fuel oxygenates MTBE, ETBE, TAME, TBA, DIPE, 1,2- DCA, and ethanol using EPA Method 8260B, and total lead using EPA Method 6010B. Soil and groundwater samples collected from the waste oil UST cavity will be submitted for laboratory analyses for TPHg, TPHd and TPH as motor oil (TPHmo) using EPA Method 8015M, full scan volatile organic compounds (VOCs) including fuel oxygenates MTBE, ETBE, TAME, TBA, DIPE, 1,2-DCA, and ethanol using EPA Method 8260B, and Title 22 metals using EPA Method 6010B. Waste Disposal. Groundwater generated during dewatered activities will be temporarily stored in 20,000-gallon BakerTAA water storage tanks. Excavated sail will be stockpiled on -site pending characterization and disposal. Filter Recycling, of Calton, California (Filter Recycling) will transport the soil and groundwater for proper treatment and/or disposal. Report. After completion of field work and receipt of laboratory analytical results collected during dewatering activities, SECOR will prepare a report evaluating groundwater conditions at the site. The repart will include groundwater analytical results, chain -of -custody records, and SECOR's conclusions. SCHEDULE The UST system removal and site demolition is scheduled for mid November 2005. SECOR and CPC will begin coordinating this work immediately upon approval of this IRAP by the California Regional Water Quality Control Board, Central Coast Region. IP:/ConocoPhillips/Project Folders/6293/work Plans/TRAP UST Overexcavation Dewatering 10.05 SECOR Interim Remedial Action Plan Proposing Groundwater Dewatering During 1 Underground Storage Tank System Removal 76 Service Station 6293 October 17, 2005 Page 5 If you have any questions or need additional information, please contact Mr. Jason Kornes at (714) 379-3366. Sincerely, SECOR International Incorporated Prepared by Reviewed and Approved by Jason C. Komes Kelly C. rown, RG 6714 Project Scientist Principal Geologist Attachments: Figure 1 — Site Location Map Figure 2 — Site Plan Attachment A — Field and Laboratory Procedures cc: Ms. Shari Landon, ConocoPhillips Company (Electronic File) Mr. D. Kerry Boyle, City of San Luis Obispo Fire Department IP:/ConocoPhillips/Project Fold ers/6293/work Plans/TRAP UST Overexcavation Dewatering 10.05 SECOR mot•. : _a�'<_,� ,!'W) •'• - --+f•� ' .._._ : I _._�.� ti _: �•..•.: \' - � �i, �;;II'I•_' _. , -ti c.I, 11 -J '.(/'/'/�-•_. ..,.,t. _� '7,_ -_, ..,•._,r..,"Ivey.�'-.max• '_}� E • 3 - _ 'I J. + ■ � L+ • ' '' � ,:r-:fir • i • —_. ., Apo. tioil i'-• ,. J i I LAW ';'• � 1, :u �F7.�i1fa'forrcr •�,� ~n': +�3,>� ;� � �.: f`ti� l ti y . (' T J `� Ik��CI,`'�. �' lri 1�" �- '�` t.. 'j ] ••� 11• ,� .' �, e. 5'F� l..•t.{� fps -_ _ �atp •J 4 • r �� ai.,rot.AL-'7ii+ �t-. �s r !t "�; t}_ _ nn .c x -- --•i :f' I f • � •-:'..:r '3q_ `. .�: -ice •z.- :•. �-. _� � - I I •' ��titi - � tiaH ETA _ xp,?• I r)�F jinn �F.1w,�1 ���~ .—� � .'-I'''I � SITE 911i2 _ }a' Ros �' i. • r r •�.: y 1�., ;r_..� - �.}_ .... �-+-, a `I{r- ..", - / . . water �1 a ]an "Lank +J WadY5ls6at 4 2 �3h'10 o [KS �zV uyR t� �. .;1r• L`''�'- .-.-� .:.y yr, _ 1 L + -`' 4rrs� _ ; J7 �.i115 Di�IS o Y•-ak ' aao SV 252 -1 jlI '1, f � _ 1 -� J'. _ . ' 1ti •' , .... '4 1 `..,•I �r t � 4'. ••+; I' , ..�; N• ��•^ }' ` f, �;1. I .ac< Esc 15 lia �24,y �4'T �.. r. .. .� `l ••'» r• ., +.1..L. ,'} r ,v a '��.• .1' f i`� r'-,L,�!\� • ^... '"-= I I: e':iL_ ''� 'yam•. I • I •I{-.; fi`:r. 4 404kxe • :tip t"'r . 'ti Rrx urrdt � • fi = � � � -r, f .+ 1 '� ' rJl� ti �\ • .r+4 • r• �, 41-.-� 'f �:•�: :d,F L'�� r\ fy F /' S ±OARS• �-r4' SCALE IN FEET �°' �' T ► -ice Source, 3-D To oQuads Co rl ht 1999 e !-_ ` ' ` �"'�.. f - �• P PY 9 D Lormer' .......�w�... - z9T FOR: FIGURE: CONOCOPHILLIPS 76 STATION NO.6293 SITE LOCATION MAP S E C O R SAN LUIS OBISPO, CALIFORNIA 11085 KNOTT AVENUE SUITE B ORANGE COUNTY, CALIFORNIA JOB NUMBER: DRAWN BY: CHECKED BY: APPROVED BY: DATE: PHONE: (714) 379-3366/379-3375 (FAX) 14CP.86293.01 T,ARCHIBALD M.CALKINS I K. BROWN 07/20/05 FILEPATH: X:\Cad 2003\Secor Out Office\Cypress Offic076 Station 6293\(;PR29,9 2SP riwp ATTACHMENT A FIELD AND LABORATORY PROCEDURES Interim Remedial Action Plan for Dewatering of Groundwwater during Underground Storage Tank System Removal 76 Service Station 6293 363 Santa Rosa Street San Luis Obispo, California II I I ATTACHMENT A FIELD AND LABORATORY PROCEDURES Organic Vapor Procedures The PID or FID will be calibrated prior to over -excavation activities. Results of the field-testing will be noted on the field data sheets. PID and FID readings are useful for indicating relative hydrocarbon levels, but cannot be used to evaluate petroleum hydrocarbon concentrations with the confidence of laboratory analyses. Soil and Groundwater Sampling Procedures Soil and groundwater samples will be collected into appropriate EPA -approved containers, labeled, logged onto a chain -of -custody document, and transported on ice to a California state - certified laboratory for analyses. Laboratory Procedures Soil and groundwater samples will be shipped to the laboratory under chain -of -custody protocol and analyzed for the presence of TPHd using EPA Method 8015M, and TPHg, BTEX and fuel oxygenates MTBE, ETBE, TAME, TBA, DIPS, 1,2-DCA, and ethanol using EPA Method 8260B. Excavated Soil and Removed Groundwater Excavated soil cuttings and removed groundwater generated during over -excavation operations will be stored at the site in pending characterization and disposal. The soil and ground water will be removed from the site by Filter Recycling and transported to a California -licensed disposal facility for proper disposal and/or treatment. PACIFIC ENVIRONMENTAL GROUP INC. May 20, 1997 Project 311-149.113 Ms. Tina Berry Tosco Marketing Company 2000 Crow Canyon Place, Suite 400 San Ramon, California 94583 Re: Work Plan for Site Assessment Unocal Service Station 6293 363 Santa Rosa Street at Montalban Street San Luis Obispo, California Dear Ms. Berry: 11Az MAT On behalf of Tosco Marketing (Tosco), Pacific Environmental Group, Inc. (PACIFIC) has prepared this, work plan to assess soil and groundwater conditions at the site referenced above. This work plan was prepared in response to a city of San Luis Obispo Fire Department (SLOFD) letter request dated March 7, 1997. The SLOFD requested that a site assessment be performed to determine the extent of hydrocarbon -impacted soil and groundwater beneath the service station property. This work plan includes discus- sions of site background, the proposed scope of work, and an implementation schedule. BACKGROUND Facility Description The project site is an operating Unocal service station located in the city of San Luis Obispo. Facility features include two 12,000-gallon capacity gasoline underground stor- age tanks (USTs); one 550-gallon waste oil tank; two dispenser islands; and a service station building (Figure 1). Previous Site Investigations On February 2 and 8, 1997, the gasoline and waste oil USTs were uncovered and the product and vapor recovery lines were excavated and removed. During excavation activities, PACIFIC performed air monitoring and collected groundwater and confirmation soil samples in areas approved by the SLOFD. Field procedures and soil 2025 Gateway Place, Suite 440, San Jose, California 95110 (408) 441-7S00 FAX (408) 441-7539 May 20, 1997 Page 2 and groundwater analytical data are documented in PACIFIC's Excavation A'fon7torr77g and Samplh7g - Tank Top Replacement Report, dated April 4, 1997. Groundwater was encountered within the UST excavations at a depth of approximately 4 feet below ground surface (bgs). Before completely uncovering the tanks, a water collection trench was excavated near the southern end of the gasoline UST complex. Approximately 5,200 gallons of groundwater was then pumped from the waste -oil and gasoline UST excavations and was stored on site in a Baker tank. A total of 11 confirmation soil samples were collected from beneath the dispenser islands (D-1 through D-4) and product lines (PP-1 through PP-7) (Figure 1). In addition, one water sample was collected from the dewatering trench located at the southeast corner of the gasoline UST complex (GW-1), and one water sample (GW-2) was collected from the Baker tank for profiling. Total purgeable petroleum hydrocarbons calculated as gasoline (TPPH-g) was detected in soil samples D-3 and D-4 at a concentration of 1.3 milligrams per kilogram (mg/kg). Benzene was not detected in the soil samples at concentrations above laboratory method reporting limit (MRL), and only minor concentrations of other toluene were detected in soil samples D-2, D-3, and D-4. Soil samples PP-1 through PP-6 contained no TPPH-g and BTEX compounds. Soil sample PP-7 contained minor concentrations of toluene (0.009 mg/kg) and xylenes (0.035 mg/kg). The groundwater sample collected from the dewatering trench (GW-1) contained TPPH-g at a concentration of 140 micrograms/liter (µg/L) and methyl.tert-butyl ether (MtBE) at 140 µg/L. Benzene was not detected in sample GW-1 at a concentration above the laboratory MRL. The groundwater sample collected from the Baker tank: following all dewatering activities contained 2,400 µg/L TPPH-g, 33 µg/L benzene and 3,300 µg/L MtBE. PROPOSED SCOPE OF WORK To assess soil and groundwater conditions beneath the service station property, PACIFIC will drill four exploratory borings and convert the borings into groundwater monitoring wells designated MW-1 through MW-4 at the locations shown on Figure 1. Boring MW-1 will be drilled to assess soil and groundwater conditions in the vicinity of the gasoline UST complex, and Borings MW-2 through MW-4 will be drilled to further assess the lateral extent of groundwater impact and to determine the groundwater gradient and flow direction. Based on the south sloping local surface topography as well as our discussigns with Regional Water Quality Control Board, Central Coast Region staff familiar with local hydrogeologic conditions, it is anticipated that groundwater beneath the site flows in a southwesterly to southeasterly direction. Groundwater is anticipated to occur at depths between 5 and 15 feet bgs. 3111491 BrNRKPLN May 20, 1997 Page 3 Task 1 - Prefield Activities Prior to conducting field activities, PACIFIC will obtain well installation permits from San Luis Obispo County, Department of Environmental Health (DEH). In addition, PACIFIC will prepare a site -specific health and safety plan, schedule inspectors from the appropriate agencies, and contact Underground Service Alert at least 48 hours before initiating drilling activities. Task 2 - Exploratory Soil Borings Groundwater is anticipated to occur at depths between 5 and 15 feet bgs, therefore exploratory Borings MW-1 through MW-4 will be drilled to a depth of between 15 and 25 feet bgs, or 10 feet below first encountered groundwater using continuous -flight, hollow -stem auger equipment. The 8-inch diameter auger flights will be steam cleaned prior to drilling each boring. Undisturbed soil samples will be collected from the borings at 5-foot depth intervals using a 1.5-foot long nominal 2-inch diameter, split tube -type sampler equipped with brass sample liners. The sampler will be advanced into soil ahead of the lead auger using a standard 140-pound slide hammer. Once a soil sample has been collected, the sampler will be withdrawn from the auger and the sample liners will be removed. One sample liner from each sampling interval will be retained, sealed with Teflon® tape and plastic end caps, placed in an insulated cooler, and transported under chain -of -custody to a state -certified laboratory for analysis. The soil samples will also be field screened for organic vapors using headspace analysis and a photo -ionization detector (PID) calibrated to 100 parts per million (ppm) isobutylene gas. A detailed log of the boring will be recorded by a PACIFIC geologist based on the soil samples and auger return material. Soil will be logged according to the Unified Soil Classification System (ASTM C2488-69). Soil cuttings generated during drilling activities will be stockpiled and covered with plastic sheeting, and auger rinsate will be contained in labeled 55-gallon DOT -approved drums. The stockpiled soil and drums will be stored on site pending consideration of disposal options. Task 3 - Well Completion Exploratory Borings MW-1 through MW-4 will be converted into groundwater monitor- ing wells by installing 2-inch diameter PVC blank and 0.02-inch slotted casing. The wells will be screened from approximately 5 to 25 feet bgs. A filter pack of Lonestar 2x12 sand will be placed in the annular space of each well from 1 foot above the slotted interval to the total depth of each boring. A bentonite seal will be placed and extend approximately 1 to 2 feet above the sand pack. The remaining annular space surrounding the blank casing will be backfilled with Portland cement grout, or 3111491B/VaWLN May 20, 1997 Page 4 equivalent, to approximately 1 foot bgs. Each well head will then be secured with a lockable well cap, secured with a padlock and enclosed in a water -tight traffic -rated steel well box set in concrete.. Task 4 - Well Development and Sampling Monitoring Wells MW-1 through MW-4 will be developed to restore the natural hydraulic conductivity of the formation, remove sediments from the well casing, and stabilize the filter pack. Groundwater -level measurements will be recorded prior to development, and the wells will be developed using a surge block and 2-inch diameter submersible pump. During development, water will be purged and monitored for turbidity, pH, temperature, and conductivity until these parameters stabilize. Within 48 hours after being developed, the wells will be gauged, purged of three to four casing volumes of groundwater, and monitored for the above parameters. When the groundwater parameters stabilize groundwater samples will be collected from the wells. The groundwater samples will be transferred to containers appropriate to each EPA analytical method being used. The samples will be labeled, stored in a chilled cooler, and transported to a state -certified laboratory along with the chain -of -custody documentation. Purge water generated during well development and sampling activities will be transported off site for treatment and recycling at Tosco's Rodeo Refinery. Task 5 - Laboratory Analyses Selected soil and groundwater samples from Wells MW-1 through MW-4 will be analyzed for TPPH-g and benzene, toluene, ethylbenzene, and xylenes by EPA Methods 8015 (modified) and 8020, respectively. In addition, the groundwater samples will be analyzed for MtBE by EPA Method 8020. The maximum concentration of MtBE, if detected, will be confirmed by EPA Method 8260. Task 6 - Report Preparation Following completion of the field activities and receipt of the analytical results, the data will be evaluated. A summary report of the findings will be prepared that will include the following: ■ Description of previous site investigation activities. ■ Regional and site -specific geology and hydrogeology. • Description of field procedures. • Exploratory boring logs and well construction details. • Updated site map. 3111491 BAVRKPLN May 20, 1997 • Page 5 ■ Results of chemical analysis of soil and groundwater samples with copies of certified analytical reports and chain -of -custody documenta- tion. * A discussion of findings and conclusions. SCHEDULE PACIFIC is prepared to implement the scope of work upon approval of the work plan by the SLOFD. Monitoring well installation permit applications will be forwarded to the DEH during May 1997. We anticipate that the field activities will be completed in June and a summary report documenting the results of the investigation will be submitted to the SLOFD in July 1997. Should you have any questions or require additional information, please call. Sincerely, Pacific Environmental Gro C. JOSEPH J. MUZZ10�� No. j672 qJ Muzzio CERTIFIED k Project Geologist ENGINEEN140 CEG 1672 GEOLOGIS �P 9rF OF c uFo- Attachments: Figure 1 - Pro onitoring Well Location Map - cc: Mr. Frank DeMarco, Regional Water Quality Control Board, Central Coast Region Mr. Spencer Meyer, City of San Luis Obispo Fire Department 3111491 B/VJRKPLN PLANTER x U Q O rx a, Q APPROXIMATE EXTENT MW-3 OF WASTE OIL TANK EXCAVATION WASTE OIL TANK LUBE BAY rx 'a SERVICE STATION MW-2 BUILDING a rn a MW-1 PP-1 ' . . -n-1I �_---- .:..7 . PRODUCT ■ ;. ; } UNDERGROUND ISLAND (TYP) ■ I ! ; E FUEL STORAGE D-2 D-1 3GA,-I � � : TANK (TYP) rl O i PP-4 ■ .. a [PROPANE ° TANK------� o D-4 D-3 ■ • APPROXIMATE EXTENT o*--GUARD POST OF UST EXCAVATION 0 0 (TYP) PP-7 PP-6 PP-5 ° MW-4 0 APPROACH SIDEWALK APPROACH SANTA ROSA STREET LEGEND D-4, PP-7 ■ SOIL SAMPLE LOCATION AND DESIGNATION GW-I+ GROUNDWATER GRAB SAMPLE LOCATION AND DESIGNATION W laiJi MW-4 -f� PROPOSED GROUNDWATER MONITORING WELL LOCATION AND DESIGNATION E z a H SCALE 0 20 40 FEET Reference: 911/149/Sllemp20.n d