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HomeMy WebLinkAboutPD 2023-0009; THE WILLIAMS RESIDENCE; SECOND ROUND OF THIRD-PARTY GEOTECHNICAL REVIEW; 2024-03-14Geotechnlcal & Environmental Sciences Consultants March 14, 2024 Project No. 109343016 Ms. Jessica Nishiura Hunsaker & Associates 9707 Waples Street San Diego, California 921 21 Subject: Second Round of Third-Party Geotechnical Review Additional Construction at The Williams Residence 2723 Cazadero Drive Carlsbad, California 92009 Dear Ms . Nishiura: At your request, we have prepared this letter regarding our third -party review of the second geotechnical submittal for the subject project. Based on our review, the information provided in the referenced letter prepared by GeoSoils (2024) has generally addressed the comments presented in our original review letter (Ninyo & Moore, 2023) and we have no further comments at this time. We appreciate the opportunity to be of service. Respectfully submitted , NINYO & MOORE Christine M. Kuhns, PE Project Engineer CMK/JTK/mp Attachment: References J/in~:GE Principal Engineer 5710 Ruffin Road I San Diego, California 92123 Ip. 858.576.1000 I www.ninyoandmoore.com Geotechnlcal & Environmental Sciences Consultants April 24, 2023 Project No. 109343016 Ms. Jessica Nishiura Hunsaker & Associates 9707 Waples Street San Diego, California 92121 Subject: Third-Party Geotechnical Review Additional Construction at The Williams Residence 2723 Cazadero Drive Carlsbad, California 92009 Dear Ms. Nishiura: At your request, we have prepared this letter providing our review comments to the referenced geotechnica l report prepared by GeoSoils (GS I) dated March 1, 2019. Our comments regarding the geotechnical report include the following: Comment 1: The Geotechnical Consultant should review the project grading and foundation plans and provide any additional geotechnical recommendations, as appropriate, and indicate if the plans have been prepared in accordance with the geotechnical recommendations provided in the referenced geotechnical report (GSI, 2019). Comment 2: Per the City of Carlsbad (1993) guidelines, the Geotechnical Consultant should provide a geotechnical cross-section of the site. Additionally, an updated geotechnical map/plot plan showing the location of the cross-section should be provided. Comment 3: The Geotechnical Consultant should show the lateral limits of the recommended remedial grading on the geologic/geotechnical map. Comment 4: The referenced geotechnical report (GSI, 2019) utilizes the standards provided by the 2016 California Building Code (CBC) and American Society of Civil Engineers (ASCE) 7-10. As the standards of the 2022 CBC and ASCE 7-16 are the currently accepted practices, the Geotechnical Consultant should update the report and applicable sections utilizing those standards. Specifically, the sections regarding seismic shaking should be updated to incorporate the more conservative design values determined using ASCE 7-16 standards. Comment 5: The referenced geotechnical report (GSI, 2019) references the County of San Diego BMP Design Manual (2016), the geotechnical consultant should review the City of Carlsbad BMP Design Manual (2023) and provide an updated recommendations and/or worksheets based on the City of Carlsbad BMP Design Manual (2023). 5710 Ruffin Road I San Diego, California 921231 p. 858.576.1000 I www.ninyoandmoore.com Comment 6: The Geotechnical Consultant should provide a statement regarding the impact of the proposed grading and construction on adjacent properties and improvements. Comment 7: The Geotechnical Consultant indicates on page 6 of the refe ren ced geotechnical re port (GSI, 2019), that the colluvium " ... may be reused as pro perly engineered fill, in areas proposed for settlements-sensitive improvements." However, on page 16 of the referenced geotechnical report (GSI, 201 9) it says "Colluvial soils are anticipated to be expansive and should not be used for the support of structures .... most of the colluvi al soils within the construction area wi ll li kely be exported." The Geotechnical consultant should clarify the suitability of the colluvial soils. Comment 8: The Geotechnical Consultant indicates on page 17 of the referenced geotechnical report (GSI, 2019), that temporary slopes up to 15 feet in height may be excavated at a ½: 1 (H:V) for Type A soils. The Geotechnica l Consultant should clarify if these recommendations for temporary slopes apply for excavations in fill and colluvial soils. Comment 9: The project plans (City of Carlsbad, 2022)) show permeable pavers adjacent to the existing and proposed structures. The Geotechnical Consultant should comment on the su itability of the infiltration elements be ing adjacent to these structures and to provide recommendations for setbacks or mitigation measures, as appropriate. Comment 9: The referenced geotechnical report (GS I, 2019) is over 4 years old. The Geotechnical Consultant should consider performing a site visit to confirm site conditions and update the report accordingly. We appreciate the opportunity to be of service. Respectfully submitted, NINYO & MOORE ~mtk Christine M. Kuhns , PE Project Engineer CTF/CMK/JTK/mp Attachment: References /i?::::- Principal Engineer Ninyo & Moore I 2723 Cazadero Drive, Carlsbad, California I 109343016 I April 24, 2023 2 REFERENCES American Society of Civil Engineers (ASCE), 2017, Minimum Design Loads for Buildings and Other Structures, ASCE 7-16. Ca lifornia Building Standards Commission, 2022, California Building Code: Californ ia Code of Regulations, Title 24, Part 2, Volum es 1 and 2. City of Carlsbad, 1993, Technical Guidelines For Geotechnical Reports: dated January. City of Carlsbad., 2022, Grading Plans for Williams Residence, 2723 Cazadero Dr., Carlsbad, CA 92009, APN : 215-400-12-00, City of Carlsbad: November 28. City of Carlsbad, 2023, BMP Design Manual: dated January 11. GeoSoils , Inc. (GSI), 2019, Geotechnical Evaluation for Additional Construction at the Williams Residence, 2723 Cazadero Drive, Carlsbad, Sa n Diego County, California 92009, W.O. 757 4-A-SC: dated March 1. Ninyo & Moore I 2723 Cazadero Drive, Carlsbad, California I 109343016 I April 24, 2023 3 ,. GSi Geotechnical •Geologic• Coastal• Environmental 5741 Palmer Way Suite D, Carlsbad, CA 92010 TEL: (760) 438-3155 -FAX: (760) 931-0915 www.geosoilsinc.com Geo Soi ls , Inc. February 12, 2024 W.O . 7574-A2-SC Mr. Greg Williams 2723 Cazadero Drive Carlsbad, Ca lifornia 92009 Subject: References: Response to City of Carlsbad Review Comments, 2723 Cazadero Drive, Carlsbad, County of San Diego, Californ ia 92009 1. "Geotechnical Evaluation for Additional Construction at the Williams Residence, Proposed Improvements at 2723 Cazadero Drive, Carlsbad, County of San Diego, California 92009," W.O. 7574-A2-SC, dated March 1, 2019, by GeoSoils, Inc. 2. "Third Party Geotechnical Review, Additional Construction at the Williams Res idence, Proposed Improvements at 2723 Cazadero Drive, Carlsbad, County of San Diego, California 92009," Project No. 109343016, dated April 24, 2023, by Ninyo & Moore. 3. "California Office of Statewide Health Planning and Development (OSHPD), 2023, Seismic design maps, https://seismicmaps.org/. Dear Mr. Williams: In accordance with your request, GeoSoils, Inc. (GSI) is providing this response to City of Carlsbad review comments. The scope of our services has included a review of the referenced report and City comments (Reference Nos. 1 and 2), analysis and presentation of data, and preparation of this response. Unless specifically superceded herein , the conclusions and recommendations contained in the referenced report by GSI (Reference No. 1 ), remain pertinent and applicable, and should be appropriately implemented during planning, design and construction. GSI REVIEW RESPONSE For convenience, the reviewer's comments are repeated below in italics, followed by GSl's response. Comments Comment No. 1 The Geotechnica/ Consultant should review the project grading and foundation plans and provide any additional geotechnical recommendations, as appropriate, and include if the plans have been prepared in accordance with the geotechnica/ recommendations provided in the referenced geotechnical report (GS/, 2019). Response to Comment No. 1 GSI has re vi ewed the proj ect grading and fo undation plans, and found the general recommendations have been incorporated into the plans, in accord ance with the geotechnical recommendations provided in the referenced geotechnical report (GSI, 2019). Comment No 2 Per the City of Carlsbad (1993) guidelines, the Geotechnical Consultant should provide a geotechnical cross-section of the site. Additionally, an updated geotechnica/ map/plot plan showing the location of the cross-section should be provided. Response to Comment No. 2 Acknowledged. A re vi sed geotechnical map, showing the location of the Cross-Section X-X' is included (see Plate 1 -Geotechni cal Map, rear of text). In additi on, Cross-Section X-X' has been generated for the site depicting the planned improvements and underlying geologic units (see Plate 2 -Geologic Cross-Section X-X', rear of text). Comment No. 3 The Geotechnical Consultant should show the lateral limits of the recommended remedial grading on the geo/ogic/geotechnical map. Response to Comment No. 3 Acknowledged. A revised geotechnical map, showing the lateral limits of the recommended remedial grading is included on Plate 1. Comment No . 4 The referenced geotechnical report (GS/, 2019) utilizes the standards provided by the 2016 California Building Code (CBC) and American Society of Civil Engineers (ASCE) 7-10. As the standards of the 2022 CBC and ASCE 7-16 are the currently accepted practices, the Geotechnica/ Consultant should update the report and applicable sections utilizing those standards. Specifically, the sections regarding seismic shaking should be updated to incorporate the more conservative design values determined using ASCE 7-16 standards. Response to Comment No. 4 Acknowledged. The seismic section regarding seismic shaking has been updated to incorporate the more conservative design values determined using the 2022 CBC and ASCE 7-16 standards (see below). Mr. Greg Williams 2723 Cazadero Drive, Carlsbad File:e:\wp21\7500\757 4a2.rtc GeoSoils,lnc. W.O. 7574-A2-SC February 12, 2024 Page 2 SEISMIC DESIGN General In the event of an upper bound (max imum probable) or credible earthquake occurring on any of the nearby major fau lts, strong ground shaking would occur in the subject site's general area. Potential damage to any structures would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass. This seismic potential would be no greater than that for other ex istin g structures and improvements in the immediate vi cinity. Seism ic Shaking Parameters The following table summarizes the site-specific design criteria obtained from the 2022 CBC, Chapter 16 Structural Design , Section 1613, Earthquake Loads for the centroid of the site, 33.1041 latitude, -117.2451 longitude. The computer program Seismic Des ign Maps, provided by the Cal ifornia Office of Statewide Health Planning and Development (OSHPD, 2023) has now been used to aid in design (https://seismicmaps.org). The short spectral response uses a period of 0.2 seconds. 2022 CBC SEISMIC DESIGN PARAMETERS PARAMETER Risk Category Site Class Spectral Response -(0.2 sec), Ss Spectral Response -(1 sec), S, Site Coefficient, F. Site Coefficient, Fv Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec), SMs Maximum Considered Earthquake Spectral Response Acceleration (1 sec), SM, 5% Damped Design Spectral Response Acceleration (0 .2 sec), S05 Mr. Greg Williams 2723 Cazadero Drive, Carlsbad File:e :\wp21 \7500\7574a2.rtc VALUE I, II, or Ill C 0.946 0.346 1.2 g 1.5 g 1.135 g 0.519 g 0.756 g GeoSoils,lnc. 2022 CBC/ASCE REFERENCE Table 1604.5 Section 1613.3.2/Chap 20 ASCE 7-16 (p. 203-204) Section 1613.3.1 Figure 1613.3.1(1) Section 1613.3.1 Figure 1613.3.1 (1) Table 1613.3.3(1) Table 1613.3.3(2) Section 1613.3.3 (Eqn 16-37) Section 1613.3.3 (Eqn 16-38) ASCE 7-16 (Eqn 11.4-3) W.O . 7574-A2-SC February 12, 2024 Page 3 2022 CBC SEISM IC DESIGN PARAMETERS PARAMETER VALUE 2022 CBC/ASCE REFERENCE 5% Damped Design Spectral Response 0.346 g ASCE 7-16 (Eqn 11.4-4) Acceleration (1 sec), S0 , PGA,.1 0.494 g ASCE7-16 (Eqn 11.8.1) Seismic Design Category D ASCE 7-16 (Table 11.6-1) GENERAL SEISMIC PARAMETERS PARAMETER VALUE Distance to Seismic Source (Rose Canyon Fault)''1 ±7.3 mi (11 .8 km) Upper Bound Earthquake (Rose Canyon Fault) Mw = 7.2<21 Pl -From Blake (2000) 121 -Cao, et al. (2003) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life, not to eliminate all damage, since such design may be economically prohibitive. Cumulative effects of seismic events are not addressed in the 2022 CBC (CBSC, 2022) and regular maintenance and repair following locally significant seismic events (i .e., Mw5.5) will likely be necessary, as is the case in all of Southern California. Comment No. 5 The referenced geotechnical report (GS/, 2019) references the County of San Diego BMP Design Manual (2016), the geotechnical consultant should review the City of Carlsbad BMP Design Manual (2023) and provide an updated recommendations (sic) and/or worksheets based on the City of Carlsbad BMP Design Manual (2023). Response to Comment No. 5 Acknowledged. A desktop study was performed in late January 2024 using Table D.1-1: Considerations for Geotechnical Analysis of Infiltration Restrictions (attached) and Table D.2-1: Elements for Determination of Design Infiltration Rates (attached) according to the City of Carlsbad BMP Design Manual (2023). According to the results of Table D.1-1 and Table D.2-1, the site is considered "restricted" and the site BMP's should be designed with an initial infiltration rate of 0.025 in/hr. As a note, K & S Engineering, Inc. was contacted to confirm the planned installation of permeable pavers in the driveway area, and they stated the permeable pavers have been eliminated from the construction plans. Mr. Greg Williams 2723 Cazadero Drive, Carlsbad File:e:\wp21 \7500\7574a2.rtc GeoSoils ,lnc. W.O. 7574-A2-SC February 12, 2024 Page 4 Comment No. 6 The Geotechnical Consultant should provide a statement regarding the impact of the proposed grading and construction on adjacent properties and improvements. Response to Comment No. 6 The planned improvements are in the rear yard of the existing residence. The lot to the east of the site is undeveloped. The adjacent lot to the south is a developed lot with a sing le-family residence with rear yard pool. The planned improvements will not impact the vacant lot to the east due to the 5-foot setback of the planned retaining wall or the developed lot to the south, with a 20-foot wide drainage/sewer easement. Comment No. 7 The Geotechnica/ Consultant indicates on page 6 of the referenced geotechnica/ report (GS/, 2019), that the colluvium " ... may be reused as a properly engineered fill, in areas proposed for settlement-sensitive improvements." However, on page 16,of the referenced geotechnica/ report (GS/, 2019) it says "Colluvial soils are anticipated to be expansive and should not be used for the support of structures ... mostcolluvia/ soils within the construction area will likely be exported." The Geotechnica/ consultant should clarify the suitability of the colluvial soils. Response to Comment No . 7 On page 6 of the referenced geotechnical report, the statement reads , "All colluvium is considered prone to settlement under loading and therefore should be removed and may be reused as properly engineered fill , in areas proposed for settlements(sic)-sensitive improvements." So, the colluvium is considered "prone to settlement under loading," and should only be reused in areas with settlement-sensitive improvements if mixed with enough non-expansive soils to yield expansion test values of 20 or less. The colluvium can also be used in other areas where no settlement-sensitive improvements are planned, as is. Otherwise, the statement, " ... most colluvial soils within the construction area will likely be exported ," is still considered applicable to site development conditions. Comment No. 8 The Geotechnica/ Consultant indicates on page 17 of the referenced geotechnical report (GS/, 2019), that the temporary slopes up to 15 feet in height may be excavated at a ½/1 (H:V) for A type soils. The geotechnical consultant should clarify if these recommendations temporary slopes apply for excavations in fill and colluvial soils. Mr. Greg Williams 2723 Cazadero Drive, Carlsbad File:e:\wp21 \7500\7574a2.rtc GeoSoils,lnc. W.O. 7574-A2-SC February 12, 2024 Page 5 Response to Comment No. 8 As encountered in Test Pits 1 through 5 (GS I, 201 9), the fill and colluvium were only observ ed to be 1 to 2 feet in thickness in the im provement area. As such, these surficial materials should be removed before excavating "deeper cuts" (i.e. basement excavation). As stated in the report, "all cut slopes shou ld be mapped by a geologist during construction. Although not anticipated at this time, should intersecting planes of joints/fractures daylight the cut slope face, or should undocumented fill, colluvium, or highly weathered bedrock be exposed in cut slopes, remed ial grad ing including stabi li zation fills or inclin ing the cut slope to a gradient flatter than the adverse structure may be necessary. The type of remed ial grad ing wou ld be based on the cond itions exposed during cut slope construction." For sha ll ow "cuts," (i .e. less than 2 feet in height), the colluvium and fill soils should ad here to a con ventional 1: 1 (horizontal:vertical [h:v]) cut slope gradient. Comment No. 9 The proj ect plans (City of Carlsbad, 2022) show permeable pavers adjacent to the existing and proposed structures. The Geotechnical Consultant should comment on the suitability of the infiltration elements being adjacent to these structures and to provide recommendations for setbacks or mitigation measures, as appropriate. Response to Comment No. 9 The onsite soils are classified as belonging to Hydrologic Soil Group "D." Given the low infiltration rates and shallow depth to near-impermeable bedrock, GSI does not recommend infiltration at the site. Due to the potential for perched water and associated settlement and distress, for any BMP structure within close proximity (i.e., potentially within 1 0 feet) of any existing or planned foundations , walls, slopes , and other settlement-sensitive improvements, a"no infiltration" BMP design is warranted . Any BMP used onsite should be designed as lined . Comment No. 9 (sic, should be comment no.10) The referenced geotechnica/ report (GS/, 2019) is over 4 years old. The Geotechnical Consultant should consider performing a site visit to confirm site conditions and update the report accordingly. Response to Comment No. 10 Acknowledged. A site visit was performed on January 22, 2024. Site conditions were found to be similar to the conditions exposed in 2019. As such, no further recommendations are necessary. Mr. Greg Williams 2723 Cazadero Drive , Carlsbad File:e:\wp21 \7500\7574a2.rtc Geo Soi ls, Inc. W.O. 7574-A2-SC February 12, 2024 Page 6 The opportunity to be of service Is sincerely appreciated. If you should have any questions, please do not hesitate to contact our office. Respectfully submitted, GeoSoils, Inc. -1 ' I It } .,_ Todd M Page Engineering Geologist, TMP/SJC/JPF/sh Q. * /,9 .;!'] ~ Steph~n J. Coover Geotechnical Engineer, GE 20 Enclosures· Table 0 .1-1: Considerations for Geotechnical Analysis of Infiltration Restrictions Table 0.2-1: Elements for Determination of Design Infiltration Rates Plate 1 Geotechnical Map Plate 2 -Geologic Cross Section X-X' Distribution : (1) Addressee (PD F via email) Mr. Greg Williams 2723 Cazadero Drive, Carlsbad File:e:\wp21 \7500\7574a2.rtc Geo Soils, Inc. W.O. 7574-A2-SC February 12, 2024 Page 7 Appendix D: Geotechnical Engineer Analysis Appendix G 0 . n1ca er ly D.1 This section is only applicable if the analysis of infiltration restrictions is performed by a licensed engineer practicing in geotechnical engineering. The S\'\IQl'vIP Preparer and Geotechnical E ngineer must work collaboratively to identify any infiltration restrictions identified in Table D.1-1 below. Upon completion of this section, the Geotechnical E ngineer must characterize each Dl'vIA as Restricted or Unrestricted for infiltration and provide adequate support/discussion in the geotechnical report. A D l'vIA is considered restricted when one or more restrictions exist which cannot be reasonably resolved through site design changes. Table D.1-1: Considerations for Geotechnical Analysis of Infiltration Restrictions Mandatory Considerations Optional Considerations Result Restriction Element BMP 1s w1th1n 100' of Contam1nated Soils BMP is within I 00' of Industrial Activities Lacking Source Control Bl'vIP is within 100' of Well/Groundwater Basin BMP is within 50' of Septic Tanks/Leach Fields BMP is within 10' of Structures/Tanks/Walls Bi'vIP is within lO' of Sewer Utilities Bi'vIP is within lO' of Groundwater Table BMP is within Hydric Soils BMP is within Highly Liquefiable Soils and has Connectivity to Structures BMP is within 1.5 Times the Height of Adjacent Steep Slopes (225%) County Staff has Assigned "Restricted" Infiltration Category Bl\IP is within Predominantly Trpe D Soil BMP is within 10' of Property Line BivIP is within Fill D epths of 2 5' (Existing or Proposed) Bl\IP is witllin 10' of Underground Utilities Bl\IP is witlun 250' of Ephemeral Stream Other (Pro\·ide detailed geotechnical support) Is Element Applicable? (Yes/No) -NO NO NO YES YES NO NO NO NO NO YES YES YES YES NO Based on examination of the best available information, 0 I have not identified any restrictions above. Unrestricted Based on examination of the best available info1mation, 1K) I have identified one or more restrictions above. Restricted Table D .1-1 1s divided into Mandatory Considerations and Optional Considerations. Mandatory D-1 Jan.2024 Appendix D: Geotechnical Engineer Analysis Considerations include elements that may pose a significant risk to human health and safety and must always be evaluated. Optional Considerations include clements that are not necess arily associated with human health and sa fety, so analysis is not mandated through this guidance document. ,.-\11 elements presented in this table are subject to the discretion of the Geotechnical Engineer if adequate supporting information is provided. Applicants must evaluate infil tration res tncttons through use of the best available data. A list of resources available for evaluation is provided in Section B.2 D.2 e rm n t n f Des gn f11tr t10 Rates This section is only applicable if the determination of design infiltration rates is performed by a licensed engineer practicing in geotechnical engineering. The guidance in this section identifies methods for identifying observed infiltration rates, corrected infiltration rates, safety factors, and design infiltration rates for use in structural Bl\lIP design. Upon completion of this section, the Geotechnical Engineer must recommend a design infiltration rate for each Dl\'1A and provide adequate support/ di scussion in the geotechnical report. Table D.2-1: Elements for Determination of Design Infiltration Rates Initial Infiltration Rate Identify per Section D.2.1 0.025 in/hr Corrected Infiltration Rate Identify per Section D.2.2 NA in/hr Safety Factor NA unitless Identify per Section D.2.3 Design Infiltration Rate Corrected Infiltration Rate -c-Safety Factor NA in/hr D-2 Jan.2024 -----D:1S{ING ,it"!MOI'~ Wlil.l 10 M(IIIAIN 20 0 ~---10 I /" = 20' 20 40 I I Afu Mzu 65' "' GS/ LEGEND UNDOCUMENTED ARTIFICIAL FILL MESOZOIC METASEO/M[NTARY/ METAVOLCANIC ROCKS -UNO/VIDEO JOINT/ FRACTURE AmTUDE WITH DIP IN DEGREES __ ?__, APPROX/MA TE LOCATION OF GEOLOGIC CONTACT, QUERIED WHERE UNCERTAIN TP-6 ~ X X' APPROX/MA TE LOCATION OF EXPLORATORY TEST-PIT LOCATION OF GEOLOGIC CROSS SECTION 1---1 : :] APPROX/MA TE LATERAL LIMITS OF RECOMMENDED REMEDIAL GRADING ALL LOCATIONS ARE APPROX/MA TE This document or efile is not., p:ut of the Construction Documents :md should not be relied upon .:1s being :m :1ccurate depiction of design. GeoSoils,lnc. GEOTECHNICAL MAP Plate 1 W.O. 7574-A2-SC DATE: 02/24 SCALE: 1" = 20' DRAINAGE SEWER [AS[M[NT EASEMENT u ff_ ff_ I I I I X PROJECTED X' PROJECTED TP-5 PROJECTED W-3 !~,tU ,,..~IOJ. "'(Wt.- 500-TP-6 iw.ni ~soo PROJ[CTED I ·l EXISTING TP-I ~ PosED! ~ I RAD[ ' II GRADE Afu Mz u _ _L --~~_L,J 4 \ '!'r.:i _,,, ~ ;:o-480--480 ;:o- g ! .. , - ~ M zu g is is " ---------" ~ ~ "' Mzu "' ,;j 460-Mzu -460 ,;j 440 440 0 :io 410 610 t!a 160 ,la ,Jo 1Jo ,Jo 2bo 220 DISTANCE (FEET) N21°W ~ ALL LOCATIONS ARE APPROX/MA TE This document or cfilc is not .J p:ut of the Construction GS/ LEGEND Documents :,nd should nor be relied upon .JS being .l'n accur.,te depiction of design. Afu -UNDOCUMENTED ARTIFICIAL FILL GRAPHIC SCALE GeoSoils,lnc. 20 0 10 20 40 Mzu -MESOZOIC METASEDIMENTARY/ ~--------! GEOLOGIC CROSS SECTION --METAVOLCAN/C ROCKS -UNDIVIDED X-X' ___ ?__, -APPROX/MA TE LOCA TTON OF GEOLOGIC 1· = 20' Plate 2 CONTACT, QUERIED WHERE UNCERTAIN 7574-A2-SC I DATE, 02/24 lscALE, w,o. 1"=20'