STONEY-MILLER CONSULTANTS. INC

GEOTECHNICAL ENGINEERING & ENGINEERING GEOLOGY

May 19, 2016

Welbrook Senior Living 1568 South 500 West, Suite 102 Woods Cross, UT 84010

Attention: Mr. Ken Magargee, Principal

Subject: Soil Report Update for Due Diligence

Project No: Report No:

Supplemental Recommendations - 2013 CBC Geotechnical Update East of Mt. Hope St. and South of Warner Avenue Near 11360 Warner Avenue Fountain Valley, California

13988-00 16-13966

References: Stoney-Miller Consultants, Inc., 2010, "Preliminary Geotechnical Investigation, Rancho Las Bolsas Multi-Family Affordable Homes, Fountain Valley, California", Project No. 13466-00, Report No. 10-11303, dated November 10.

Dear Mr. Magargee:

This report presents a summary of updated recommendations for foundation design based on the 2013 California Building Code (CBC), and the results of a recent groundwater study for the subject site. It is our understanding that the anticipated site development will be a 200-room assisted living facility. Current development considers a two-story, wood-framed building as most likely, but a four-story facility is still under consideration. This update is based upon a review of the referenced study and a review of the present conditions at the site. The purpose ofthis study is to update the foundation design criteria in accordance with the 2013 California Building Code, and to update our liquefaction analysis and cuffent groundwater level.

The conclusions and recommendations of this report are preliminary due to the absence of specific foundation plans, the formulation of which is partially dependent upon the recommendations herein.

EXEXCUTIVESUMMARY

1. The property remains in essentially the same geotechnical condition as described in the referenced report.

2. Recommendations in the referenced report remain suitable for design except as modified herein.

14 HUGHES, SUITE B-101 IRVINE, CA 92618-1923 (949) 380-4886 · FAX (949) 455-9371

May 19, 2016 Project No: Report No: Page No:

13988-00 16-13966

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3. The proposed construction of a 200-unit assisted living facility remains geotechnically feasible providing the recommendations herein arc integrated into design, construction, and long-te1m maintenance of the property.

4. The site is underlain by alluvial soil comprised of interlaycrs of coarse-grained and fine­grained materials. Coarse-grained soils range from silty sand to sandy silt with consistencies from loose to medium dense. Fine-grained soils range from clay to clayey silt with consistencies ranging from firm to stiff.

5. Groundwater is found at depths of 10.5 to 12 feet below existing ground surface. Saturated ground conditions are anticipated at 7 to 8 feet below existing grade. Recent groundwater fluctuations (2009 to 2013) are estimated at +/- one foot. Refer to recent groundwater study in Appendix A.

6. The primary change in the California Building Code is the mandate to consider a maximum considered earthquake with a return period of 2,475 years, instead of just a more moderate earthquake with a return period of 475 years. This results in larger ground accelerations which increases the potential settlements from soil liquefaction during earthquakes.

7. Portions of the alluvial soil are liquefiable during moderate and larger ground motions. This results in ground settlement due to soil liquefaction. Moderate levels of ground shaking are estimated to cause seismic ground settlement in the range of 4 to 5 inches. Maximum considered levels of ground shaking are estimated to cause ground settlement in the range of 5 to 6 inches.

8. It is probable that additional site investigation, laboratory testing, and engineering evaluation could reduce the estimated ground settlements from liquefaction to about 2 to 3 inches. This additional work is estimated to cost approximately $25,000.00 which include two borings to 50 feet, collection of SPT samples at about 3 foot intervals, laborat01y testing to determine plasticity and grain size of the soil materials, re-evaluation of settlements from liquefaction, and preparation of a comprehensive report.

9. Foundations for 2-story buildings could then be supported on a conventional foundation and slab or mat foundation provided column loads arc limited to 75,000 pounds, bearing pressures are limited to 1,500 pounds per square foot, and remedial grading is perfonned as provided in the referenced report. Total settlement under dead plus live loading is estimated at 1 inch or less. Total settlements under seismic loading would be less than 4 inches.

l 0. Foundations for 4-story buildings could then be supported on a conventional foundation and slab or mat foundation provided column loads arc limited to I 00,000 pounds, bearing pressures are limited to 1,500 pounds per square foot, and remedial grading is perfr)rmed as

May 19, 2016 Project No: Report No: Page No:

13988-00 16-13966

3

provided in the referenced report. Total settlement under dead plus live loading is estimated at 1.5 inch or less. Total settlements under seismic loading would be less than 4 inches.

LIMITATIONS

This evaluation has been conducted for feasibility of development in accordance with generally accepted practice in the engineering geology and soils engineering field. No further wananty is offered or implied. The conclusions presented herein are based on surface conditions observed during on onsite review and are not meant to imply a control of nature. Independent use of this report in any form cannot be approved unless written verification is obtained from this firm.

The conclusions presented in this report are based on a surface reconnaissance of the site and nearby sunounding areas in conjunction with data obtained from available documents, reports, and maps as referenced. A supplemental geotechnical subsurface investigation should be performed prior to site development to further evaluate the existing subsurface geologic and foundation conditions as they relate to planned site development.

Respectfully submitted,

STONEY-MILLER CONSULT ANTS, INC.

1Z~ uc~ Russell C. Lamb Chief Geotechnical Engineer, G.E. 2207 Registration Expires 3-31-17 Date Signed: / /

RCL:fp

Attachments: Appendix A, Evaluation of Local Groundwater Conditions

APPENDIX A

EVALUATION OF LOCAL GROUNDWATER CONDITIONS

STONEY-MILLER CONSULTANTS, INC

GEOTECHNICAL ENGINEERING & ENGINEERING GEOLOGY

May 19, 2016

Welbrook Senior Living 1568 South 500 West, Suite 102 Woods Cross, UT 84010

Attention:

Subject:

Mr. Ken Magargee, Principal

Evaluation of Local Groundwater Conditions East of Mt. Hope St. and South of Warner Avenue Near 11360 Warner Avenue Fountain Valley, California

Dear Mr. Magargee:

Project No: Report No:

13988-00 16-13966gw

Presented below are our findings regarding local groundwater conditions at 11360 Warner A venue in Fountain Valley, California (the Site). An initial study consisted of extracting available groundwater elevation data from the State Water Resource Control Board web Site (http://geotracker.waterboards.ca.gov/) which provides information for nearby water supply wells and local environmental cleanup sites associated with leaky undergrounds storage tanks (LUST Sites). A second study including excavating five backhoe pits onsite and measuring groundwater levels.

Previous Studies

Our previous study of the site was documented in our preliminary geotechnical report dated January 21, 2011. Our subsurface work was performed between October and December 2010.

Groundwater was encountered in all hand-auger borings at depths of 7.8 to 9.6 feet below existing grades (Elevations 31.4 to 33.9 feet ams!). During insertion of the Cone Penetration Test Probes, pore pressure dissipation tests were performed to aid in estimating groundwater levels. These tests indicated water levels at a depth of 8.5 feet (Elevation 33.7 feet ams!) in CPT-1, and at a depth of 7 .5 feet (Elevation 34 feet ams!) in CPT-2, respectively. Groundwater was also encountered in our hollow-stem auger boring (Boring HSA-1) at a depth of approximately 5 feet below existing grade (Elevation 36.3 feet ams!).

Initial Research

Numerous environmental sites are located in the general vicinity of the Project Site. We reviewed 12 sites in close proximity of the Project Site and based on distance from the Project Site, completeness of the data, and distance from the Santa Ana River, selected and reviewed three sites (listed below) in more detail to evaluate the general variability of groundwater in the area. The Santa Ana River is a dominate groundwater feature in the Site area and influences (i.e.; dampens) groundwater variability in the area.

14 HUGHES, SUITE B-101 IRVINE, CA 92618-1923 (949) 380-4886 · FAX (949) 455-9371

Mayl9,2016 Project No: Rcp011 No: Page No:

13988-00 16-13966

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Groundwater elevations at the following three LUST sites were evaluated to understand the amount of groundwater variability to be expected at the Project Site.

• Fountain Valley Regional Hospital (FVRH) at 17100 Euclid St. (I, 150 feet west); • Exxon Mobil Oil Corporation Service Station at 16230 Harbor Ave. {6,410 feet northeast), and • Orange County Sanitation District (OCSD) Plant I at 10844 Ellis Ave (8,000 feet south).

The location of these sites relative to the Project Site is presented on Figure I. The findings of this work are summarized in Table 1. As indicated on Table I, for the period of record available, the maximum groundwater fluctuation observed in any monitoring well at each Site ranged from 6.42 feet (FVRH) to 3.69 feet (Exxon Mobile Service Station) and 13.29 feet (OCSD Plant 1). A plot of groundwater elevations for these wells is provided on Figure 2. These wells are highlighted on Table 1. For these wells the maximum and minimum depth to groundwater measured from a reference point near or at ground surface ranged as follows:

• Fountain Valley Regional Hospital (Well MW-6) • Maximum depth to groundwater= 12.04 feet bgs • Minimum depth to groundwater= 5.25 feet bgs

• Exxon Mobile Service Station (Well MW-8) • Maximwn depth to groundwater= 11.33 feet bgs • Minimum depth to groundwater= 8.27 feet bgs

• Orange County Sanitation District Plant I (Well MW-10) • Maximum depth to groundwater= 26.21 feet bgs • Minimum depth to brroundwater = 12.92 feet bgs

Based on this infonnation, we conclude that groundwater fluctuations observed at the FVRH are most representative of groundwater conditions at the Project Site. Based on existing data, groundwater fluctuations at the Project Site would be expected to be approximately 6.5 feet. As shown on Figure 2, a linear trend line was fitted to existing data for the FVRH site indicating that brroundwater conditions appear to be generally increasing (i.e. rising) over time. The more recent trend from December 2009 to December 2013 shows a maximum variation of 2 feet.

Site Trenching

Stoney-Miller Consultants, Inc. excavated five backhoe pits at the site on May 13, 2016 at the approximate locations shown in Figure 3. Backhoe pits were excavated to depths between 10.5 to 12 feet bgs, and then left open for at least 2 hours before measuring the depth to groundwater. Backhoe pits were then backfilled with the excavated soil by tamping with the backhoe bucket.

Based on this recent work, the depth to groundwater at the Site ranges from approximately 9.0 feet to 10.3 feet bgs. l11e average depth to water across the Site was I 0.12 feet bgs. Groundwater elevations based on existing grade range from 29.7 to 32.5 feet navd88 and averaged 31.5 feet navd88. Assuming that worst case h'Toundwater fluctuation is approximately+/- 3.25 feet around the average groundwater conditions as

May 19, 2016 Project No: Report No: Page No:

13988-00 16-13966

3

demonstrated for the nearby FVRH site and assuming that the current depth to water at the Site are representative of an average condition (i.e., would fall on an average trend line for the Site if sufficient data existed), we would anticipate groundwater to fluctuate approximately +/-3.25 feet from its current elevation. The groundwater fluctuation would reduce to+/- 1 foot based on the more recent trend from 2009 to 2013.

Limitations

Our services were performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable soils engineers and geologists practicing in this or similar localities. Groundwater levels may seasonally fluctuate, or increase as a result of development, and should be anticipated to be a constraint to site development. No other warranty, expressed or implied, is made as to the conclusions and professional advice included in this report.

The opportunity to be of service is appreciated. If you have any questions, please call.

Respectfully submitted,

STONEY-MILLER CONSULTANTS, INC.

//Z~c~ Russell C. Lamb Chief Geotechnical Engineer, G.E. 2207 Registration Expires 3-31-17 Date Signed: / /

RCL:fp

Attachments: Table 1: Figure 1: Figure 2:

Groundwater Elevations at Nearby Sites Site Location Groundwater Elevations at Nearby Sites

Site Name AddrHI

l 7100 Eui.:lid Street, !Fountain Valley Rcgion.:il Hospital !founi.:iin Valley

E:<xon Mcbii Oil Corp. Scn.·1£e 632D llarbor Boulev,mJ,

Geotracker A.cftre0tt Ne.

TOl-05900090

S1ation Fmmtain Y::llcy I T06059fl103'7

IOCSD Plant No l.

S1•mma,y T~bk :,nd F,gu•c ~l,i,T3b;o I

I 0844 Elli5 A ·,rcnu~. fount.tinVal!ey T0605::1387J8

Dil4a!K'.e -1150 foe!

64iil feel

800Df'!:et

Oir«.tion

284 deg.recs

Wt:.1

No. Wells Ye-an Mm S!art End Elcnttoo (Im navdss,

Mn Elnatlon (fcci ll11Vd88}

TABLE 1

Groundw;,;t<:r Ele~tion, ror Nearby Sites

t 1360 Wamcr Avenue, Fouurnin Valley, California

Sll{C Project So. 13988

Differenee

(fort)

Dat:1 Soi.!n:e

TI;ird Quurte! :!O ! J Groundwater

10 18-Jmi-97 16-~ .IJ 25.19 \6118/97 34.M9 2~-Mar- i I 8.70 Monitoring

MW- I 18-Fcb-04 16-Sep-lJ 28.89 IO-Ma1_-0S 32.12 9-0ct-02 J .2~

MW-2 !8-Jun-97 16-~· 13 26.19 1g.Juo-1.n 3.?.12 25-Mar-ll 6.13

MW·3 i8 .. Jun~97 !6-S:!p·IJ ll.79 9-0ct-<)2 32.12 7-Mar-01 333

MW-4 11-DK-~1 16-Scf,-D 2'1.i7 9-0cl--02 31_qg 25-Ma,--!I J .l! I

MW-5 12-Dix-97 16-~IJ 2i.? 15-Jnn-99 )4.0< 25-Mar-Tl 534

M\\-o l'.!~J.kc.9:" l tl·Sc-~i--l J ZS.47 SI-O;;t-Ol ).I K~ ~ .>,w.11 6,•;2.

MW-7 !S-.Jun-:J9 16-Se,,--il 28.CJ8 lt-Ocl-0'.! 32.Jl) :?l-Jun-1.1 J.41

MW-8 l5-Jun-99 J6-Scp- i3 29.22 Y-Oct-02 JJ.76 25-Mar-i l 4.54

MW-"9 4-Aug-04 15-~p.07 30.59 17-0«-08 34,2[ 25-Mar-li 3.62

MW-El 4-Au~--04 16-Sep- lJ 30.52 18-Se_E-07 33.52 ?6-De..:-!I .HJO

213 ~:rtts I 6 (noa rcmcdialion) 2-J\:lar-92 '.!3-Mor-12 45.33 24-Feh-flJ 48.08 24-Jlln-98 2.75 !

Annual Site St.;tus and Groundwater Moniloring Re::,urt. Fir..t Qo.ia~er 201 2 {24 January 201 I lo 23 M::rch 20i 2)

205 degrees

South

MW-5 2-M.ar-92 2J-Mar-11 45.:59 19-A!.a.£-02 43.08 24-fon-98 2.49

!iAW-6 l-M:i.r-92 23-M;ir-!1 45.78 9-Dcc-:J.4 48.6 :?4-J\ln-98 2.!U

MW-7 2-Mar-92 23-Mar-12 45.62 26-1"<iov-96 48."' 24-Jun-98 2.7~

MW-II 2-Mw:-"'1 ~-\t.111-1: 4L\: ~.)..f"c::t.-fl.l 4\1.01 ~-Nu\-ll' 16'1

MW-lJ ll-0,;t-94 23-Mar-12 4.S.36 26-}".i'ov-~6 48.97 ::4-Juti-911 3.6!

MW-14 ll-Oct-94 23-Mar-i:? 45 . .S5 26·Nov-95 4!U6 24-Jun-98 2.61 Firs1 Qua;1cr 2016 Gmundwa:c.:r Monitori;1g I j 5-Mar-O:! j 26-F.:f,-16 0.47 I 24-Sco-14 I i6.34 l:?-Dct:-06 I i5.8?' j;~po~ OCSO Ptalll 1. 10844 1.:l!is Av~nt."C. i-ou~L1in Valley, CA

MW-2 15-Mar- i:l 26-Fd>-i6 7 ,()6 24-SC!J'-1<1 I0.70 12-Dc-'=-06 2.74

MW-3 l6-Se__e_-03 26-Fd>-i6 -l .56 20-iJ,ec-1)7 l.>.62 !5-J:m-06 !3.18

MW-4 lS-Ma,-11 26-l;tb-16 1.34 20-Dix-07 I !.3J 14-~p-1! 9.99

Mw-, 2.f-.Jun-10 26-Fct--!C 0.71 20-Dec--07 11.46 tS-Jnn-11 rn.75

MW-6 26-Sc..e.-03 26-FID-16 l.26 l~-Jtm-OX I0.72 14-~p-il 9.46

!\,!W-7 .24-.'un-i~ 26-Feb-!6 -0.41 19-.hm-08 !0.4} 15-Jtm-l ! 10.90

MW-8 16-Sep-03 25-r"i;:b-16 0.74 W-Dec-07 10.79 15-Jun-1! 11}.05

MW-9 5-Mar-01 26-Fdi-ft,. .1.1, 20-De.:-07 11.56 IS-Jun-I I 12.71

MW•)O S--Mar-o: 1c .. t-cb-lf• ·1.l tl ~ lkc::--Ol 12\'IJ l>Ju:i ... 11 IJ!-1

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SCALE 1 :48000 0 1000 2000 3000 4000 5000 6000 7000 E-3 E-3 E-+---3 1----+3

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SITE LOCATION MAP PROJECT NO. 13988-00 DATE: MAY 2016 FIGURE NO. 1

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FIGURE 2 Groundwater Elevations at Nearby Sites

11360 Warner Ave, Fountain Valley, California SMC Project No. 13988

-- -

-~ - -........

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-- • Linear (Fountain Valley Regional Hospital, 177100 Euclid Street)

I ~H

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Dec-91 Dec-93 Dec-95 Dec-97 Dec-99 Dec-01 Dec-03 Dec-OS Dec-07 Dec-09 Dec-11 Dec-13 Dec-15 Dec-17

Summary Table and Figure.xlsx/Fig 2 Page I of I Stoney Miller Consultants, Inc.

APPROXIMATE LOCATION OF MUD ROTARY

AND HOLLOW STEM AUGER BORING

APPROXIMATE LOCATION OF HAND AUGER

BORING

APPROXIMATE LOCATION OF PREVIOUS

BORING BY SCG

APPROXIMATE LOCATION OF CONE

PENETRATION TESTING

T?•5 APPROXIMATE LOCATION OF TEST PIT =

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GEOTECHNICAL PLOT PLAN RANCHO LAS BOLSAS

FOUNTAIN VALLEY, CALIFORNIA

CONC.

3