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Home My WebLink AboutNCP 18-0002; ECONO LODGE EXPANSION; INFILTRATION TESTING; 2018-10-29C C C C C C C .. 1111 11111 1111111 .. 1111 .. INFILTRATION TESTING Proposed Building Addition and Driveway Improvements 3666 Pio Pico Drive Carlsbad, California HETHERINGTON ENGINEERING, INC. C C ... ... ,. ... .. 1111 .. 1111 ... .. .. ... ,. '-- c C C C HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING• ENGINEERING GEOLOGY• HYDROGEOLOGY Paresh Patel Eco no lodge October 29, 2018 Project No. 8721.1 Log No. 20151 3666 Pio Pico Drive Carlsbad, California 92008 Subject: INFILTRATION TESTING Proposed Building Addition and Driveway Improvements 3666 Pio Pico Drive Carlsbad, California References: 1. "Grading Plans For: Econolodge 2-Story Expansion, 3666 Pio Pico Drive," (Sheets 1 through 5), bHA, Inc., undated . 2. City of Carlsbad, "BMP Design Manual", dated February 26, 2016. 3. "Soil Engineering Investigation Report, Proposed Two Story Hotel Building, 3666 Pio Pico Drive, Carlsbad, California", by A. E. Engineering, dated September 1, 201 7. Dear Mr. Patel: In response to your request, we have performed infiltration testing of existing fill soil and terrace deposits in the area of the proposed driveway permeable concrete pavers at the subject site. No groundwater was encountered to the maximum depth explored of 8.0- feet in the boring and test pit excavated at the site. The approximate locations of the boring and test pit are shown on the attached Plot Plan, Figure 1 and the Boring and Test Pit Logs are attached as Figures 2 and 3. Infiltration testing was performed by this office on October 23, 2018 in accordance with the Open Pit Falling Head test method. The approximate locations of the infiltration tests are shown on the attached Plot Plan, Figure 1 and the test results are shown on the attached Falling Head Infiltration Test Data Sheets, Figures 4 and 5. The infiltration rates based on the infiltration testing are 8.2 inch/hr for IP-I and 11.1 inch/hr for IP-2 (without considering safety factors). Completed I-8 and I-9 Forms are attached to this report. 5365 Avenida Encinas, Suite A• Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931-0545 www. hetheringtonengi nee ring .com C .. C ,.. L. C C C INFILTRATION TESTING Project No. 8721.1 Log No. 20151 October 29, 2018 Page2 The opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely, HETHERINGTON ENGINEERING, INC. ~ R . Edwin R. Cunningh Civil Engineer 8168 ss10nal Geologist 3 772 (expires 3/31/20) . ___ , "fied Engineering Geologist 1 "fied Hydrogeologist 591 ires 3/31/20) en Civil Engineer 30 Geo technical Engineer 3 97 ( expires 3/31/20) Attachments: Plot Plan Boring and Test Pit Logs Falling Head Infiltration Test Data Sheets I-8 and I-9 Forms Figure 1 Figures 2 and 3 Figures 4 and 5 Distribution: 1-via e-mail Shanup Patel (shanuppatel@gmail.com) 5-Addressee HETHERINGTON ENGINEERING, INC. ~-q ({VJ I {" '-' o]' ~~ 'V ,v\\; ~-,.'\r / ..... ' ,.(,1 ,,::-'\: ' ~-'-tY lr,~-" ": \, ~ ! '1 ~ ~ ~ I ~ 8 ~ "- 12' SQ CATCH BASIN TG-72.70 L,,,,,..,.-.-iG.1✓" JO' f,o:}7~[ \ 20' J0.11 f 20·]/ f~f:!it 1; \ ~ I 10' ,;:;'/ifllifj , _-1~. ;~1 ~ ::-V I ' '· 'I i-\ ii I -~ ;'~ ~ ' I I ,._I :-? I I I I I / ~ ~ 0 --~ 4 cr~UMN5 ~-~ [] CJ - ==o=- ts s~ ~vs f;:: s1;] •'I"\{ ]j~11•1tf-l1 '-.I I It . ' . I.E. 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' . $>-:!' _,, _______ .. _______ -(S> -.. __ ,_\ \,. --,,,~'" ~er l •o ~ I I ---- IP-2 ~ HA-1" TP-18 1--~-,._ ---------·--·---,._____ eu,qg ';\t' ---<S> ---(\".(),<3l~~ ~~ l I i /_ ---------~.\L --~Q"'; ;.f.£(S'l ..... _~,(· ~~~~ I I ~ ~J~ -.•• -·-····-----·~-,a 1( ~~J· ·,. s_,J"E:;"'--~cs~ ---· ~ I ~ ~xi' AC SIDEWALK -<i,,~----:,._t __________ __:,:_'J T <SJ ---,-. i """' ":;i}'' --_________ ..:_~-::_--::::::...'.'.~.-===-f.s.L==,=.;.~----·--.-:;-;--.. ~-" ~ LEGEND APPROXIMATE LOCATION OF INFILTRATION TEST PIT APPROXIMATE LOCATION OF HAND AUGER BORING APPROXIMATE LOCATION OF TEST PIT ~c-1<'.'.t. ,,, , ~~~ 0 2 0 10 20 30 40 PLOT PLAN HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS PROJECT NO. 3666 Pio Pico Carlsbad , California 8721 .1 I FIGURE NO . --DRILLING COMPANY: Mansolf RIG: Hand Auger DATE: 10/10/18 -BORING DIAMETER: 4 II DRIVE WEIGHT: DROP: ELEVATION: 74' + - ~ µ:J E-< µ:J ,-:i :>--< ~ µ:J ,-:i P-< E-< E-< dP Cl)~ µ:J P-< ~ 0 H -Cl) BORING NO. HA-1 i:r.. ~ 0 Cl) µ:J ,:i; Cl) -Cl) i:r.. z p:: E-< ,-:i --- :r:: Cl) ----µ:J p z U 0 µ:J Cl) a ~ E-< µ:J E-< :,::: :> rs: 4-1 Cl) E-< ,-:i Cl) P-< µ:J ,-:i H 0 :>--< 0 H z H a p p:: ,-:i p:: p, 0 0 0 p SOIL DESCRIPTION iXI a iXI a ::s u Cl) -~ 0.0 FILL: Light brown silty fine sand, dry, loose --SM .___ 96 2.7 ---TERRACE DEPOSITS: Red brown silty sand, moist, dens~ .___ - --~ -92 4.0 ----5.0-I--98 6.0 ---\ .___ --_..___ .___ 100 5.4 - -~ -Total depth: 8-feet No caving -No groundwater .___ --10.0----- --.___ - -.___ ---.___ ---~ - 15.0 -BORING LOG 3666 Pio Pico Drive HETHERINGTON ENGINEERING, INC. Carlsbad, California --GEOTECHNICAL CONSULTANTS PROJECT NO. 8721.1 I FIGURE NO. 2 -------------------------------------- BACKHOE COMPANY: Mansolf :r:!H H i:i1 P-, i:i1 i:i1.,.. Cl- Q,Q 5.0 10.0 15.0 :,-, i:i1 H H H :,,:; p., C/J H H;:;::ZC/J p .r: i:i1 i:i1 il1 C/J Cl H 103 113 113 C/J ~ C/J • i:i1 .r: C/J ~ H H • p :z; u u H i:i1 C/J H H C/J HZ~ H • 0001° OP ;:;:: u -C/J - 4.8 SM 4.5 6.3 BUCKET SIZE: DATE: 10(17/18 SOIL DESCRIPTION TEST PIT NO. TP-1 ELEVATION: 73' FILL: Gray silty sand with 3/4" angular gravel, dry, loose @ 1 ': Becomes brown silty sand. dry to moist, dense @ 16": Becomes dark brown, moist, dense @ 22": Glass fragment + TERRACE DEPOSITS: Red brown silty sand, moist, dense to very dense Total depth: 6-feet No caving No groundwater LOG OF TEST PITS HETHERINGTON ENGINEERING, INC. 3666 Pio Pico Drive Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8721.1 I FIGURE NO. 3 FALLING HEAD INFILTRATION TEST DATA SHEET Project Number: 8721.1 Project Name: 3666 Pio Pico Drive Test Date: 10/17/2018 Test Hole No.: IP-1 Tested By: Ray Cunningham Depth of Test Hole: 2.0 -feet uses Soll Classification at Infiltration Level: SM / Sandstone Test Hole Dimensions (feet): Length 4 Pre-Soaking Data (Over minimum of 4 hours) Time Interval Initial Depth to Date/Start Time Date/Stop Time (min.) Water (in.) 10/17/2018 11:00 AM 10/17/2018 3:00 PM 240 1.00 Infiltration Trials Trial No. Cycle Start Time Cycle Stop Time Time Interval (min.) 3:00 PM 4:00 PM 60 1 Total Time (min.): 60 Infiltration Rate for Entire Trial: 4:10 PM 5:10 PM 60 2 Total Time (min.): 60 Infiltration Rate for Entire Trial: 3 Total Time (min.): 0 I nfiltration Rate for Entire Trial: 4 Total Time (min.): 0 Infiltration Rate for Entire Trial: 1::1§ HETHERINGTON ENGINEERING, INC. IP-1 Width 2 Final Depth to Water (in.) >48.00 Initial Depth to Water (in.) 6.25 6.90 6.63 7.33 Change in Infiltration Water Rate Level (In.) (min.fin.) >47.00 <5.11 Final Change in Infiltration % Change Depth to Water Rate from Water Level (in.) (min.fin.) Previous /in.\ Cvcle 14.94 8.69 6.90 - 14.81 8.18 7.33 - % Change from Previous Trial: 6.23 - % Change from Previous Trial: - % Change from Previous Trial: Figure 4 Proj ect No. 8721.1 Lo No. 20151 rev. 10/27/2018 FALLING HEAD INFI LTRATION TEST DATA SHEET Project Number : 8721.1 Project Name: 3666 Pio Pico Drive Test Date: 10/17/2018 Test Hole No.: I P-2 Tested By: Ray Cunningham Depth of Test Hole: 2.0 -feet uses Soil Classification at Infiltration Level: SM / Sandstone Test Hole Dimensions (feet): Length 4 Pre-Soaking Data (Over minimum of 4 hours) Time Interval Initial Depth to Date/Start Time Date/Stop Time (min.) Water (in.) 10/17/2018 10:30 AM 10/17/2018 2:30 PM 240 4.00 Infiltration Trials Trial No. Cycle Start Time Cycle Stop Time Time Interval (min.) 2:30 PM 3:30 PM 60 1 Total Time (min.): 60 Infiltration Rate for Entire Trial: 3:55 PM 4:55 PM 60 2 Total Time (min.): 60 Infiltration Rate for Entire Trial: 3 Total Time (min.): 0 Infiltration Rate for Entire Trial: 4 Total Time (min.): 0 Infiltration Rate for Entire Trial: l::IEi HETHERINGTON ENGINEERING, INC. IP-2 Width 2 Final Depth to Water (in.) >36.00 Initial Depth to Water (in.) 7.87 5.16 6.44 5.40 Change in Infiltration Water Rate Level (in.) (min.fin.) >32.00 <7.50 Final Change in Infiltration % Change Depth to Water Rate from Water Previous /in.\ Level (in.) (min.fin.) Cvcle 19.5 11.63 5.16 - 17.56 11.12 5.4 - % Change from Previous Trial: 4.59 - % Change from Previous Trial: - % Change from Previous Trial: Figure 5 Project No. 8721.1 Lo No. 20151 rev. 10/27/2018 Part 1 -Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria Screening Question Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Yes No X Provide basis: Two infiltration tests using Open Pit Falling Head test method were performed in the fill and terrace deposits in the area of the proposed permeable concrete pave rs. The test results were 8.2 in/hr and 11.1 in/hr (without considering safety factors). See "Infiltration Testing ... ", by Hetherington Engineering, Inc., dated October 29, 2018. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. X Provide basis: Infiltration in the area of the proposed permeable concrete pavers is considered acceptable from a geotechnical standpoint provided that the geotechnical recommendations included in the "Geotechnical Investigation ... " are implemented during design and construction. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Criteri a 3 Screening Question Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Yes No X Provide basis: Storm water pollutant concerns in the area of the proposed permeable concrete pavers are unknown at this lime. The boring and test pit at the site with a maximum depth of 8-feet did not encounter groundwater. Infiltrated water will migrate at least 8-feet before reaching groundwater. In addition, we are not aware of any known soil contamination present at the site. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. X Provide basis: No ephemeral streams are present at the site. Groundwater was not encountered to a depth of at least 8-feet and we are not aware of any contaminated groundwater in the site vicinity. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Part 1 Result * If all answers to rows 1 -4 are ''Yes" a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 Full Infiltration *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings. Appendix I: Forms and Checklists Part 2 Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria 5 Screening Question Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Yes X Provide basis: Due to providing a "Full Infiltration" result to Part 1, this criteria need not be answered. See response to Criteria 1. No Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Due to providing a "Full Infiltration" result to Part 1, this criteria need not be answered. See response to Criteria 2. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 1-5 February 2016 Criteria 7 Appendix I: Forms and Checklists Screening Question Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Yes No X Provide basis: Due to providing a "Full Infiltration" results to Part 1, this criteria need not be answered. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. X Provide basis: This question requires the expertise of water-rights lawyers to determine if any violation can be expected downstream by reducing the runoff via infiltration of the water into the bioretention basin. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. s LL *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by the City to substantiate findings. 1-6 February 2016 Factor of Safety and Design Infiltration Rate Worksheet Form I-9 Factor Category Factor Description Assigned Factor Product (p) Weight (w) Value (v) p=wxv Soil assessment methods 0.25 1 0.25 Predominant soil texture 0.25 1 0.25 Suitability Site soil variability 0.25 1 0.25 A Assessment Depth to groundwater I impervious 0.25 2 0.50 layer Suitability Assessment Safety Factor, SA= :Ep 1.25 Level of pretreatment/ sediment loads expected 0.5 1 0.5 B D esign Redundancy/ resiliency 0.25 1 0.25 Compaction during construction 0.25 3 0.75 Design Safety Factor, Sa = :Ep 1.50 Combined Safety Factor, S,01,1= SA x Sn 1.88 Observed Infiltration Rate, inch/hr, Kob,crvcd IP-1 and IP-2= ( corrected for test-specific bias) 9.7-inch/hr. (ave) Design Infiltration Rate, in/hr, Kdcsign = Kobscrvcd / S,otal IP-1 and IP-2 = 5.2-inch/hr. (ave) Supporting Data Briefly describe infiltration test and provide reference to test forms: Two Open Pit Falling Head infiltration tests were performed. See "Infiltration Testing ... " by Hetherington Engineering, Inc., dated October 29, 2018.