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HomeMy WebLinkAboutCT 97-09; La Costa Lucky Sav-On Shopping Center; Tentative Map (CT) (7)Engineering, Corporate Office: 619.942.5147 Environmental Sciences and 605 Third Street Fax 619.632.0164 &.ASSOCIATES Management Services Encinitas, California 92024 A California Corporation October 15, 1996 196269-12 Mr. Mike Bardin Assistant General Manager 1960 La Costa Avenue Carlsbad, CA 92009 RE: ARCO Station Contamination Impacts on LCWD Facilities Dear Mike: The Leucadia County Water District (District) has expressed concern that the District's pipelines in the vicinity of the La Costa Avenue and El Camino Real intersection may have been impacted by the petroleum hydrocarbon release at the former ARCO station. In this regard, Dudek & Associates, Inc. has performed preliminary investigation of the status of the contamination problem at the former ARCO Station through review of the County of San Diego's Hazardous Materials Management Division (HMMD) files on this site. There is concern regarding impact on the pipelines since petroleum hydrocarbons can permeate the polyethylene encasement on the force mains and many types of joint gasket rubber. The extent to which the contamination has impacted the force mains (polyethylene lined, gaskets), and the sewer pipe (gaskets (and pipeline, if PVC)) is unknown. Furthermore, there exists the possibility that the petroleum hydrocarbons may have traveled down pipeline trenches due to the higher hydraulic conductivity of the pipe bedding material. Presented below is a review of our findings. SITE BACKGROUND In 1985 the steel underground storage tanks (UST) at the ARCO station at 7654 El Camino Real were removed. At that time, liquid phase hydrocarbons (LPH) were observed on the groundwater beneath and adjacent to the removed gasoline USTs. Approximately 6,000 gallons of LPH and water were pumped prior to the installation of four new fiberglass reinforced USTs. Since 1991, HMMD has received quarterly ground water quality monitoring reports for the site. Between 1988 and 1985, approximately 31 soil boreholes and 12 groundwater monitoring wells were installed on and off-site. A variety of information on groundwater levels, monitoring well locations, and contaminate concentrations exist in the HMMD file. In July 1995, the USTs were removed from the site. In an attempt to remediate the site, over 5,000 cubic yards of soil was excavated from the former ARCO facility in November, 1995. Due to adjacent utilities, sidewalks, and driveways, some hydrocarbon-impacted soils with concentrations above 1,000 milligrams per kilogram (mg/kg) were not removed in two locations - one on the west sidewalk (along El Camino Real) and one on the north sidewalk (adjacent to the La Costa Plaza driveway). Mr. Mike Bardin Page2 Leucadia County Water District October 15, 1996 A review of the information in the HMMD files indicates the flow of groundwater to generally be in a north, north-west direction towards Batiquitos Lagoon. Most of the remaining contamination is at the west and north boundaries of the former ARCO station. A review of the fluctuating groundwater level information indicates that at times the groundwater could have been above the bottom of the existing District pipelines in the area. There are four District pipelines which may be impacted: 24" Leucadia Force Main, 12" Failsafe Line, 18" gravity sewer and the 12" abandoned Vulcan Avenue Force Main. It does not appear from a review of the data that contamination from the ARCO site will impact the proposed new 24" Parallel Leucadia Force Main alignment south of the ARCO station on La Costa Avenue. CURRENT STATUS With the removal of most of the contaminated soil at the site, the concentrations of total petroleum hydrocarbons (TPH) have been decreasing. Figure 1 depicts the current levels of contamination as of August 1996. In an August 1, 1996 letter to Mr. Nasser Soinitof the HMMD, SECOR International Inc. (SECOR), on behalf of ARCO Products Company (ARCO) requested closure of the site due to the reduction in contamination levels. HMMD staff indicated in a conversation with Dudek that the site will not be closed until contamination levels are reduced further. The SECOR letter of August 1, 1996 indicates that the force mains and sewer lines "could be impacted by hydrocarbons dissolved in groundwater," but that the District did not report hydrocarbon odors or impact in the lines or the line trenches. Furthermore, the letter states: "Additional assessment in the area of MW-13 would be limited because of the sewer lines. The Leucadia Water District has already demonstrated their resistance to assessment adjacent to the sewer lines, therefore it is anticipated that permission to perform additional assessment or excavation of a small volume of hydrocarbon impacted soil is unlikely." Dudek understands from discussions with District staff that, in fact, the District has been cooperative with SECOR's efforts to assess the contamination close to the District's facilities. To our knowledge there has been no resistance to further assessment adjacent to the sewer, in fact, the District should insist on additional assessment and excavation. RECOMMENDATIONS We believe that SECOR has not satisfactorily proven that the District's force mains and sewer line were not impacted by the contamination at the former ARCO site. The lack of the District reporting of odors or problems with the lines does not indicate that the District's lines were not impacted. There may be contamination in the old trench (beyond the edge of the ARCO site) of the abandoned 12" force main which diagonally crosses the site. In fact, there may be contamination within the abandoned pipeline which we understand was broken open during remediation excavation and then plugged with concrete. Mr. Mike Bardin Page 3 Leucadia County Water District October 15, 1996 We recommend that HMMD be requested to direct SECOR to propose methods and a schedule for the approval of the District for SECOR to: Remove all remaining contaminated materials up to, around, and beyond the existing pipelines, while by-passing or keeping those pipelines in service. Fill and recompact the area with clean granular materials. Further inspect a portion of each force main and the sewer for possible deterioration of gasket and polyethylene encasement material. Immediately repair or replace any damaged LCWD pipelines for the full length of past contamination impact. We recommend that the District forward a copy of this letter to Mr. Nasser Soinit, HMMD, regarding the District's concerns and recommendations for further contamination removal and utility inspection and repair or replacement. We recommend that a copy of this letter also be forwarded by District staff to Mr. Dwight Worden, District Attorney, for information and possible future action. Because waterlines are generally installed shallower than sewer lines as indicated in the SECOR report, adjacent waterlines may not have been affected. However, we recommend that a copy of this letter and attachments also be forwarded by District staff to Mr. Bob Greaney, City of Carlsbad, for his possible action with regard to potential impact on Carlsbad Municipal Water District waterlines. If you have any questions, please call me at 942-5147. Very truly yours, DUDEK & ASSOCIATES, INC. Steve Deering, California &fe. 26514 LCWD District Engineer Attachments: List of Figures with References Letter from Ms. Patricia McConnell, SECOR to Mr. Nasser Soinit, HMMD dated August 1, 1996 Mr. Mike Bardin Page4 Leucadia County Water District October 15, 1996 LIST OF FIGURES Figure 3a Borings, Monitoring Wells, Cross-Section Lines, and Approximate Extent of Hydrocarbon- Affected Soil Reference: Alton Geoscience, Site Assessment Report, date March 11, 1993 Figure 7 Estimated Lateral Extent of Free Product and Benzene Plumes, and Ground Water Laboratory Results (September 4, 1992) Reference: Alton Geoscience, Site Assessment Report, date March 11, 1993 Figure 4 Remaining THP in Soil Note: This figure does not show existing water lines (Dudek, 10/08/96). Reference: Letter from Ms. Patricia McConnell, SECOR to Mr. Nasser Soinit, HMMD dated August 1, 1996 UJcc o O _i UJ — P _ HA-7 DISPENSER PUMP ISLANDS HA-6 UNDERGROUND STORAGE TANKS -^ 1 •- ^ '" MW-1 I ...W-7 HA-8 A MW-6 -13 -12 f 1 1 / / ii STATION I BUILDING \ \ \ \ \ 4-— T HA-9 • • ^^\A/; Oil i MW- HA-2 \ MW-2 ',v?> ^>^ ^ LEGEND HA-8 A. Hand Auger Boring HA-12 A Hand Auger Slant Boring B-5 0 Boring MW-l -^- Monttorlng Well A~~~A' Cross-Section Line Affected Interval 4 fbg Product Una (approximate location) ALTON GEOSCIENCE 5764 PACIFIC CENTER BLVD. SUITE 101 SAN DIEGO. CA 92121 u BORINGS, MONITORING WELLS, CROSS-SECTION LINES, AND APPROXIMATE EXTENT OF HYDROCARBON-AFFECTED SOIL NOTES: Figure redrawn from 1991 maps by EA Engineering, Science, and Technology. All structure, boring, and well locations are estimated, ppm = parts per million. TPH = total petroleum hydrocarbons. Approximate extent of adsorbed-phase plume based on 100 ppm TPH. Interval depths are in feet below grade. See Figures 4 and 5 for cross-sections.Scate(Feet) ARCO Station 1939 7654 El Camlno Real Carlsbad, California FIGURE 3a 600130-20-SC2 9-30-92 MW-4 TPH B T E X J «t ii v D2 1 <J Jii ND ND ND ND ND / DISPENSER / .• PUMP ISLANDS 1 B339 LEGEND Monttorlna Well with Benzene Concentration In mg/l _ JM.-Til.. :i4. MW-5 Jk Monitoring Well with Free (0.18)*~T" Product Thickness In Feet / ~ ". Estimated Lateral Extent %.„>' of Free Product Plume .•***/ Estimated Lateral Extent ; • of Benzene Plume* ; Greater than 0.001 mg/l Product LJne (approximate location) Dlssoh/ed-Phase Hydrocarbon Concentrations In mg/I ALTON GEOSCIENCE 5764 PACIFIC CENTER BLVD. SUITE 101 SAN DIEGO. CA 92121 ESTIMATED LATERAL EXTENT OF FREE PRODUCT AND BENZENE PLUMES, AND GROUND WATER LABORATORY RESULTS NOTES: Extent of plumes is interpretive based on data collected September 4,1992; mg/l = milligrams per liter; B = benzene; T = toluene; E = efriytbenzene; X = total xytenes; NO = below detection limits stated in official Laboratory Reports. For additional laboratory results, refer to the Table. * = free product thickness in feet September4,1992 ARCO Station 1939 7654 El Camlno Real Carlsbad, California FIGURE? 600130-20-SC2 10-6-92 LEGEND HA-8 A HAND AUGER BORING WW-11-^- MONITORING WELL — S — SEWER LINE (6-9 ft. bgs\ FIBER OPTIC LINE (WAX. 3 ft. fag's) * TRAFFIC SIGNAL LINE (WAX. 3Xft. bgs) ELECTRICAL LINE (WAX. 3 ft. bgs) SOIL SAMPLE LOCATION TOTAL PETROLEUM HYDROCARBONS MILLIGRAMS PER KILOGRAM ESTIMATED AREAS OF REMAINING HYDROCARBONS NOTE: BASE WAP, INCLUDING SITE DIMENSIONS AND WELL/ BORING LOCATIONS. MODIFIED FROM ALTON GEOSCIENCE. 1994. APPROXIWATE SCALE IN FEET NOTE: ALL LOCATIONS AND DIMENSIONS ARE APPROXIMATE BASED ON AVAILABLE DATA. SECOR 1939TP4.DWG REMAINING TPH IN SOIL FORMER ARCO FACILITY #1939 7654 EL CAMINO REAL CARLSBAD, CALIFORNIA PROJECT No.: 80600-017-13 FIGURE: 4 LEGEND FAH.SAFE 12" ACP 24" DIP 24" VCP GRAVITY ELEVATIONS A City of Carlsbad Planning Department November 21, 1996 Tom Hageman Planning Systems Suite 100 2111 Palomar Airport Road Carlsbad, CA. 92009 SUBJECT: LA COSTA PLAZA - PRE 96-56 APN: 216-124-02 A preliminary review of your project was conducted on November 14, 1996. Listed below are the issues raised by staff. Please note that the purpose of a preliminary review is to provide you with direction and comments on the overall concept of your project. The preliminary review does not represent an in-depth analysis of your project. Additional issues of concern may be raised after your application is submitted and processed for a more specific and detailed review. Planning: 1. The General Plan Land Use Map identifies a portion of the proposed site as being Open Space. However, this designation seems to be in conflict with the existing La Costa Plaza development. Therefore, In order to help facilitate an administrative determination of the land use boundaries, a constraints map should be submitted identifying "constrained land", flood plain, and other natural features. In addition, the LCWD parcel has a General Plan designation of Public Utilities. Use of parcels with either Open Space or Public Utilities designations will require a General Plan Amendment. 2. The property abuts the El Carriino Real corridor and is therefore subject to a Special Use Permit. 3. Gas stations are allowed within the neighborhood commercial zone with a Conditional Use Permit. 4. The site has a Neighborhood Commercial zoning with a "Q" overlay which means that a Site Development Plan must be processed for the any development. 2O75 Las Palmas Dr. • Carlsbad, CA 92009-1576 • (619) 438-1161 • FAX (619) 438-O894 )MiPRE 96-56 LA COMR. PLAZA November 21,1996 PAGE 3 14. A traffic study may be required to determine if additional improvements are warranted on La Costa Avenue, such as: • Eliminating the left turn move out of the proposed driveway on La Costa Avenue; • Providing an unsignalized dual left turn lane on La Costa Avenue ; • Widening the roadway in this area to improve sight distance; • Installing a traffic signal; • Providing a dedicated right turn lane for the driveway entrance; • Median improvements. 15. The layout of the onsite circulation should be designed with obvious and clearly defined points of access and main traffic aisles through the center. This may be accomplished by providing wider traffic aisles, lane striping, and having the aisles free of parking stalls to avoid conflicts between through traffic and vehicles backing out. 16. Circulation for the gas station site should be designed to avoid conflicts with traffic using the driveway entrance on El Camino Real. 17. The alignment in front of the Water District offices appears awkward and could be confusing to drivers. 18. Truck turning radii should be plotted on the site plan to demonstrate that trucks can safely access the loading area. This may require larger radij on the raised curb islands in the vicinity of the loading area. 19. The filing of a boundary adjustment plat will be required for the proposed land trade with Leucadia County Water District. 20. The site plan should include a plotting of the 100-year base flood elevation for the before and after development condition. Since this property is located within the 100-year flood plain, the proposed development will also require the filing of a Special Use Permit: Floodplain application. 21. Future project plans should identify the drainage pattern for the site and include measures to treat surface runoff onsite prior to entering the public storm drain system. This issue is related to the City's requirements of the National Pollutant Discharge Elimination System (NPDES) permit, which requires a project to provide best management practices to reduce surface pollutants to an acceptable level prior to discharge. Methods found to be acceptable include directing runoff from paved November 18, 1996 TO: CHRISTER WESTMAN, ASSOCIATE PLANNER FROM: Associate Engineer Quon VIA: Principal Civil Engineer / LA COSTA PLAZA, PRE 96-56 We offer the following comments: 1. With regard to access off El Camino Real for this particular site plan, one driveway opening will be allowed with right and left turns in, and right turns out. This driveway opening will require the construction of a deceleration lane along the project frontage. 2. Any discretionary application for development of this site will include conditions of approval to provide the following frontage improvements: * Sidewalk, curb, and gutter along El Camino Real and La Costa Avenue; + Raised concrete landscaped median on El Camino Real; » Dedication of right-of-way and installation of a deceleration lane fronting the project on El Camino Real; » Dedication of 13' of right-of-way and installation of a dedicated right-turn lane on La Costa Avenue. 3. A traffic study may be required to determine if additional improvements are warranted on La Costa Avenue, such as: » Eliminating the left turn move out of the proposed driveway on La Costa Avenue; * Providing an unsignalized dual left turn lane on La Costa Avenue ; * Widening the roadway in this area to improve sight distance; » Installing a traffic signal; * Providing a dedicated right turn lane for the driveway entrance; * Median improvements. 4. The layout of the onsite circulation should be designed with obvious and clearly defined points of access and main traffic aisles through the center. This may be accomplished by providing wider traffic aisles, lane striping, and having the aisles free of parking stalls to avoid conflicts between through traffic and vehicles backing out. 5. Circulation for the gas station site should be designed to avoid conflicts with traffic using the driveway entrance on El Camino Real. 6. The alignment in front of the Water District offices appears awkward and could be confusing to drivers. 7. Truck turning radii should be plotted on the site plan to demonstrate that trucks can safely access the loading area. This may require larger radii on the raised curb islands in the vicinity of the loading area. 8. The filing of a boundary adjustment plat will be required for the proposed land trade with Leucadia County Water District. 9. The site plan should include a plotting of the 100-year base flood elevation for the before and after development condition. Since this property is located within the 100-year flood plain, the proposed development will also require the filing of a Special Use Permit application. 10. Future project plans should identify the drainage pattern for the site and include measures to treat surface runoff onsite prior to entering the public storm drain system. This issue is related to the City's requirements of the National Pollutant Discharge Elimination System (NPDES) permit, which requires a project to provide best management practices to reduce surface pollutants to an acceptable level prior to discharge. Methods found to be acceptable include directing runoff from paved areas towards a landscaped swale prior to reaching the storm drain; or installing an onsite drainage basin specially designed to remove pollutants. Please forward the red-lined check print to the applicant. If you have questions regarding any of the comments above, please contact me at extension 4380. KENNETH W. QUON Associate Engineer