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UPDATE TO

L ,

SUBSURFACE ENGINEERING GEOLOGY AND PRELIMINARY SOILS INVESTIGATIONS

TRACT NO. 14326 EAST SIDE OF PLUNGE CREEK NORTH OF GREENSPOT ROAD

HIGHLAND, CALIFORNIA PREPARED FOR

SUNCAL COMPANIES JOB NO. 97599-3

I I I I

j II ~ • ~ • J • INCORPORATED P.O. Box 231 • 1355 E. Cooley Dr .. Collon, CA 92324 • Phone (909) 824·721 o • Fax (909) 824-7209

December 24, 1997

SunCal Companies Job No. 97599-3

I 550 West Orangethorpe

Placentia, California 92870

I Attention: Mr. Ben Anderson/Mr. Bob Barjam

I I I I I I I I I I I I I

Subject: Update to Subsurface Engineering Geology Investigation and Preliminary Soils Investigation

Tract No. 14326 East Side of Plunge Creek, North of Greenspot Road Highland, California

References: See Attached List

Dear.Mr. Anderson and Mr. Barjam:

As requested, we have prepared this update to the Subsurface Engineering Geology Investigation

(Rasmussen, March 30, 1990) and the Preliminary Soils Investigation (C.H.J., Inc., June 6,

1990) for Tract No. 14326. The purpose of this update was to review new fault hazard data

from a property adjacent to the site, to observe the site as it presently exists, and to provide

necessary geologic and geotechnical recommendations for development of the site based on

current geotechnical standards.

To orient our update, a set of 40-scale Rough Grading Plans, dated September 28, 1993, and

prepared by Bonadiman Engineers, Inc., was provided for our use. The Rough Grading Plans

do not include proposed structure footprints.

The results of our update, together with our conclusions and recommendations, are presented

in this report.

SOILS ENGINEERING • GEOLOGY • ENVlR0NMEN1AL • MATERIALS TESTING 8i EVALUATION 6 GONSTRUCllON INSPECTION

I I I I I I I I I I I I I I I I I I I

SCOPE OF SERVICES

Page No. 2 Job No. 97599-3

The scope of services provided during this update included this following:

•

•

•

•

•

Review of published and unpublished literature and maps, including new data

regarding fault hazards from a report prepared for the property immediately north of the site (Suitt, February 29, 1992).

Review and analysis of stereoscopic aerial photographs flown in 1938, 1955, 1964, 1965, 1971, 1972, 1978, 1986, and 1991.

A geologic and geotechnical field reconnaissance of the site and surrounding area, conducted during September, 1997.

Excavation and geologic logging of approximately 200 feet of trench to provide additional subsurface coverage for the human occupancy structures within the

Alquist-Priolo Earthquake Fault Zone at the site.

Evaluation of the new geologic and soils engineering data to develop specific recommendations for development of the site in accordance with current geotechnical standards.

PROJECT CONSIDERATIONS

The project grading plans indicate that the tract will be developed with a total of 325 lots with

single-family residences. No significant changes· to the grading plans have occurred since the

referenced Subsurface Engineering Geology Investigation (Rasmussen, March 30, 1990) and

Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990) were prepared, except that the

"future Baseline Street R/W" area in the northeast portion of the site has been re-designed and

the street eliminated. The grading plans show proposed cut and fill slopes up to a maximum

height of approximately 15 feet. All cut and fill slopes are indicated on the grading plan at

inclinations of 2 horizontal (h) to 1 vertical (v) and flatter.


SITE DESCRIPTION


The project is now located within the City of Highland. At the time of this update, the existing

improvements and land uses at the site and in the immediate vicinity were generally the same

as those described in the referenced Preliminary Soils Investigation and Subsurface Engineering

Geology Investigation. No significant changes in the condition of the property were noted,

except that a large steel water reservoir has been constructed in what was fonnerly the northwest

comer of the property (former Lot "B"). Greenspot Road has been widened and improved with

curb and gutter along the southerly property boundary.

FAULTING

The northeast portion of the tract lies within an Alquist-Priolo Earthquake Fault Zone designated

by the State of California to include traces of active faulting associated with the San Bernardino

segment of the San Andreas fault. A subsurface engineering geology investigation was

conducted by others (Rasmussen, March 30, 1990) to address the fault hazard. That

investigation included excavation and geologic logging of approximately 1,047 feet of fault

trench and was intended to satisfy the requirements of the Alquist-Priolo Act. Due to

restrictions imposed on the areas that could be trenched associated with existing improvements,

including the North Fork Canal, the trace of the San Andreas fault was not encountered. A

setback of 100 feet from the northeast extent of trenching was recommended for human

occupancy structures (Rasmussen, March 30, 1990). A setback was also recommended

associated with the steep narural slope in the northeast portion of the site (Rasmussen, March

30, 1990).

Approximately two years after the Rasmussen investigation was conducted, a subsurface fault

investigation was conducted on the property immediately north of the site and east of Plunge

Creek (Suitt, February 29, 1992). That investigation included excavation and logging of five

geologic trenches totaling 1, 797 lineal feet, and was also intended to satisfy the requirements of

the Alquist-Priolo Act.



A significant difference is evident between the reports prepared by Rasmussen (March 30, 1990)

and by Suitt (February 29, 1992) with respect to the location and trend of faulting. The

restricted use zone associated with fault hazards that was recommended by Rasmussen trends

N51W, while the restricted use zone recommended by Suitt trends N60W immediately adjacent

to the site. In addition, the fault zone as determined by Suitt is located farther to the southwest

(approximately 100 feet) than the fault zone as delineated by Rasmussen. Based on projection

of the N60W fault trend from Suitt's southeastern-most trench to the site, the Rasmuss.en

investigation does not provide complete subsurface coverage with respect to the new (Suitt's)

fault data. Therefore, this update included additional trenching to provide subsurface coverage

with respect to the projection of Suitt's fault trace.

A single trench 200 feet in length and 15 feet deep was excavated in the northeast portion of the

property on September 16 through September 20, 1997. The trench was excavated with a Case

580E extendahoe with a 24-inch bucket. The trench walls were benched or sloped back to

increase their overall stability. The total width of the trench at the ground surface was

approximately 20 feet. Due to loose granular soil conditions and extreme caving, cleaning and

logging of the trench walls was conducted immediately after excavating each bite with the

backhoe. After logging, the trench generally caved to approximately 12 feet deep. The City

of Highland was notified of the trenching. The City's consulting geologist, Mr. Michael Cook

of Converse Consultants Inland Empire, inspected the trench. The trench log is included as

Enclosure 2. The location of the trench is shown on Enclosure I.

'The trench was placed so as to provide deep subsurface coverage of the entire length of

Rasmussen's Trench 4, plus an additional 100 feet to the southwest of the southwest end of

Rasmussen's T-4. The northeast end of the trench was placed approximately coincident with the

northeast end of T-4; the backfill from T-4 is shown on Enclosure 2. The southwest portion

of the trench was oriented slightly more westerly than the northeast end to avoid rupturing an

active concrete irrigation pipeline.



The trench exposed relatively well-bedded fluvial and alluvial sands and silty sands with minor

gravel and cobbles. Most of these materials were probably deposited by former channels of Oak

Creek. Several poorly developed, discontinuous and superposed organic soil horizons

(pedogenic 'A' soils) were observed in the trench. No significant degree of weathering or soil

development was observed in the alluvial materials in the trench. Based on geomorphology and

the degree of soil development, the alluvial materials are est.imated to be 2,000 to 3,000 years

m age.

Overall, the stratigraphy observed in the trench was similar throughout its length. No evidence

for faulting was observed in the alluvium exposed in the trench. No evidence for faulting at

depth, such as folding or warping of the alluvial materials, was observed. Therefore, the

original restricted use zone as recommended by Rasmussen (March 30, 1990) remains valid and

should be adhered to.

The trench was backfilled and wheel rolled with the backhoe. No other compactive effort was

applied to the trench backfill. The trench backfill from this investigation, from the Subsurface

Engineering Geology Investigation (Rasmussen, March 30, 1990) and from the Preliminary Soils

Investigation (C.H.J., Inc., June 6, 1990) is considered to be unsuitable for support of structures

or streets.

CONCLUSIONS

An additional 200 feet of 15-foot deep trench was excavated and logged across the site in order

to provide complete subsurface coverage of the site with respect to faulting reported by others

(Suitt, February 29, 1997) north of the site. No evidence of faulting was found.

All conclusions included in the Subsurface Engineering Geology Investigation (Rasmussen,

March 30, 1990) and in the Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990) remain

valid.



A significant amount of uncompacted backfill was generated associated with the Subsurface

Engineering Geology Investigation (Rasmussen, March 30, 1990), associated with the

Preliminary Soils Investigation (C.H.J., Inc, June 6, 1990) and associated with the trench

excavated during this investigation. This backfill is considered to be unsuitable for support of

structures or streets.

RECOMMENDATIONS

ADDITIONAL RECOMMENDATION:

In all building pad and street areas, the geologic trench backfill from this investigation and from

the Rasmussen investigation (March 30. 1990). as well as backfill from trenches placed during

the Preliminary Soils Investigation (C.H.J .. Inc .. June 6. 1990) should be removed and replaced

as compacted fill in accordance with the recommendations for fill placement included in the

Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990).

PREVIOUS RECOMMENDATIONS:

All recommendations included in the Subsurface Engineering Geology Investigation (Rasmussen,

March 30, 1990) and in the Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990) remain

valid and should be adhered to. The following is a summary of those recommendations:

SEISMIC DESIGN CONSIDERATIONS:

Severe seismic shaking of the site can be expected during the lifetime of the proposed structures.

Therefore, the proposed structures should be designed accordingly.

SETBACKS FOR HUMAN OCCUPANCY STRUCTURES:

The active San Bernardino strand of the San Andreas fault traverses the northeast portion of the

tract. Human occupancy structures .should be set back a minimum horizontal distance of 100

feet from the trace of the fault and from the steep natural slope as recommended by the

Subsurface Engineering Geology Investigation (Rasmussen, March 30, 1990). The restricted

use zone can be recovered by establishing a point 137 feet S6E from surveyed Lath IA and



projecting a line N51 W to the northern boundary of the site and a line S46E to the eastern

boundary of the site (Rasmussen, March 30, 1990).

GENERAL SITE GRADING:

It is imperative that no clearing and/or grading operations be performed without the presence

of a representative of the soils engineer. An on-site pre-job meeting with the developer, the

contractor and the soils engineer should occur prior to all grading related operations. Operations

undertaken at the site without the soils engineer present may result in exclusions of affected

areas from the final compaction report for the project.

Grading of the subject site should be performed, at a minimum, in accordance with these

recommendations and with applicable portions of the UBC. The following recommendations are

presented for your assistance in establishing proper grading criteria.

INITIAL SITE PREPARATION:

All areas to be graded should be stripped of significant vegetation and other deleterious

materials. These materials should be removed from the site for disposal. Existing irrigation

lines should be traced, capped at the property lines, removed and may be spread throughout the

fill after being crushed, as approved by the soils engineer. Any existing utility lines should be

traced, removed and rerouted from the building areas.

All existing uncontrolled fills including geologic trench backfill and the hydraulic fills identified

by the Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990) encountered during

construction should be completely removed, cleaned of significant deleterious materials and may

be reused as compacted fill. To assist in fill identification and reniovaI; we recommend that the

mandatory subexcavation areas designated on Enclosure "A-2" of the Preliminary Soils

Investigation (C.H.J., Inc., June 6, 1990) be subexcavated to a minimum depth of 18 inches

below the existing ground surface. The Soils Engineer and the Engineering Geologist should

be present during the subexcavation operation prior to scarification and refilling in order to

identify any existing fills extending below the subexcavation zone. All such fills should be



completely removed at that time. In addition, a thorough search for fill should be conducted

within the former alignment of Oak Creek as indicated on Enclosure "A-2" of the Preliminary

Soils Investigation (C.H.J., Inc., June 6, 1990). The fill search should be conducted utilizing

on-site grading equipment at the time of grading with a representative of the Soils Engineer and

the Engineering Geologist present to define and delineate the fill to be removed.

It is our recommendation that all existing fills under any proposed paved and flatwork areas be

removed and replaced with properly compacted and controlled. fills. If this is not done and any

uncontrolled fills are left beneath the pavement, premature structural distress of the paved and

flatwork areas can be expected. However, the additional cost of mandatory subexcavation and

complete fill remo.val must be compared to the higher on-going maintenance costs and other

problems caused by distressed paved and flatwork areas. It is our opinion that decreased

settlement will result from increasing the amount of existing fill removed, with complete removal

of all existing fill being the upper limit on reasonable efforts to minimize settlement. An

economic analysis of the relationship between current construction costs and on-going

maintenance costs should be undertaken to determine the most cost effective amount of fill to

be removed.

Cavities created by removal of subsurface obstructions (such as structures, individual effluent

disposal systems, and trees) and by the exploratory trenches placed on the site should be

thoroughly cleaned of loose soil, organic matter and other deleterious materials, shaped to

provide access for construction equipment, and backfilled as recommended for site fill.

PREPARATION OF FILL AREAS:

Prior to placing fill, after the mandatory subexcavation and fill search operations have been

completed, the surfaces of all areas to receive fill should be scarified to a depth of at least 12

inches. The scarified soils should be brought to near optimum moisture content and recompacted

to a relative compaction of at least 90 percent in accordance with ASTM D 1557-91.


PREPARATION OF FOOTING AREAS:


All footings should rest upon at least 18 inches of properly compacted fill material or approved

original ground soils. In areas where the required thickness of compacted fill is not accomp

lished by site rough grading or mandatory subexcavation and recompaction operations, the

footing areas should be subexcavated to a depth of at least 18 inches below the proposed footing

base grade, with the subexcavation extending at least 5 feet beyond the footing lines. In the area

designated as "Mandatory subex areas and possible hydraulic fill removal areas" on Enclosure

"A-2" of the Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990), this snbexcavation

should include the npper 18 inches of existing soils regardless if planned filling operations will

be sufficient for compacted fill requirements. The removal of the upper 18 inches of existing

soils will aid in revealing uncontrolled fill. The bottom of this excavation should then be

searified to a depth of at least 12 inches, brought to near optimum moisture content, and

recompacted to at least 90 percent relative compaction in accordance with ASTM D 1557-91

prior to refilling the excavation to grade as properly compacted fill.

COMPACTED FILLS:

The on-site soils should provide adequate quality fill material provided they are free from

organic matter and other deleterious materials. Unless approved by the soils engineer, rock or

similar irreducible material with a maximum dimension greater than 12 inches should not be

buried or placed in fills. At such time that the final project grading plan is approved, the soils

engineer should review the plan to determine suitable rock disposal areas.

Import fill should be inorganic, non-expansive granular soils free from rocks or lumps greater

than eight inches in maximum dimension. Sources for import fill should be observed and

approved by the soils engineer prior to their use.

Fill should be spread in twelve-inch or less lifts, each lift brought to near optimum moisture

content and compacted to a relative compaction of at.least 90 percent in accordance with ASTM

D 1557-91.



Based upon the relative compaction of the native soils determined during this investigation and

the relative compaction anticipated for compacted fill soils, we estimate a compaction shrinkage

of approximately 5 to 10 percent. Therefore, 1. 05 cubic yards to 1.10 cubic yards of in-place

soil material would be necessary to yield one cubic yard of properly compacted fill material.

In addition, we would anticipate subsidence of approximately 0.10 feet. These values are

exclusive of losses due to stripping, tree removal or the removal of other subsurface obstructions

and may vary due to differing conditions within the project boundaries and the limitations of this

investigation. Due to the planned removal of significant quantities of boulder-size material it

is anticipated that actual shrinkage values may exceed the value presented above.

Values presented for shrinkage and subsidence are estimates only. Final grades should be

adjusted, and/or contingency plans to import or export material should be made to accommodate

possible variations in actual quantities during site grading.

OVERSIZE MATERIAL:

Boulders to three feet were encountered within most of our exploratory trenches and are

expected to be encountered during grading. Larger boulders may also be encountered. Difficult

excavation may occur during grading and utility line installation due to oversize material at the

site.

SLOPE CONSTRUCTION:

. Cut and fill slopes should be constructed no steeper than 2(h): l(v). Fill slopes should be

overfilled during construction and then cut back to expose fully compacted soil. A suitable

alternative would be to compact the slopes during construction and then roll the final slopes to

provide dense, erosion-resistant surfaces.

Any cut slopes proposed within the recommended restricted use zone should be individually

evaluated by the engineering geologist during review of the grading plan and by geologic in

grading observation. The Rough Grading Plans dated September 28, 1993 show proposed cut

slopes up to approximately 10 feet in maximum height in the restricted use zone.



All undocumented fill materials should be completely removed prior to construction of cut or

fill slopes.

Where fills are to be placed against existing slopes steeper than 5(h): 1 (v), the existing slopes

should be benched into competent native materials to provide a series of level benches to seat

the fill and to remove the compressive and permeable topsoils. The benches should be a

minimum of 8 feet in width, constructed at approximately 4-foot vertical intervals. In addition,

a shear key should be a constructed across the toe of the slope. The shear key should be a

minimum of 15 feet wide and should penetrate a minimum of 2 feet beneath the toe of the slope

into firm competent soils.

All cut and fill slopes should be terraced in accordance with the Uniform Building Code.

SLOPE PROTECTION:

Inasmuch as the native materials are susceptible to erosion by runmng water, it is our

recommendation that the slopes at the project be planted as soon as possible after completion.

The use of succulent ground covers, such as iceplant or sedum is not recommended. If watering

is necessary to sustain plant growth on slopes, then the watering operation should be monitored

to assure proper operation of the water system and to prevent overwatering.

Measures should be provided to prevent surface water from flowing over slope faces.

FOUNDATION DESIGN:

If the site is prepared as recommended, the proposed residential structures may be safely

founded on conventional spread foundations, either individual spread footings and/or continuous

wall footings, bearing on a minimum of 18 inches of compacted fill. Footings should be a

minimum of 12 inches wide and should be established at a minimum depth of 12 inches below

lowest adjacent final subgrade level. For the minimum width and depth, footings may be

designed for a maximum safe soil bearing pressure of 1,800 pounds per square foot for dead

plus live loads. This allowable bearing pressure may be increased by 400 pounds per square



foot for each additional foot of width and by 800 pounds per square foot for each additional foot

of depth to a maximum safe soil bearing pressure of 3,000 pounds per square foot for dead plus

live loads. These bearing values may be increased by one-third for wind or seismic loading.

Due to the high percentage of boulder-size material, excavation of footings and utility trenches

in native soils may be difficult.

Footings should be set back from all slopes in accordance with information contained in

Enclosure "G" of the Preliminary Soils Investigation (C.H.J., Inc., June 6, 1990).

For footings thus designed and constructed, we would anticipate a maximum settlement of less

than 1/2 inch.

LATERAL LOADING:

Resistance to lateral loads will be provided by passive earth pressure and base friction. For

footings bearing against compacted fill or approved native soils, passive earth pressure may be

considered to be developed at a rate of 350 pounds per square foot per foot of depth. Base

friction may be computed at 0.40 times the normal load. Base friction and passive earth

pressure may be combined without reduction.

For preliminary retaining wall design purposes, a lateral active earth pressure developed at a rate

of 35 pounds per square foot per foot of depth should be utilized for unrestrained conditions.

This value should be verified prior to construction when the backfill materials and conditions

have been determined and is applicable only to level, properly drained backfill with no additional

surcharge loadings. If inclined backfills are' proposed, this firm should be contacted to develop

appropriate active earth pressure parameters. Toe bearing pressure for walls on soils not subex

cavated and recornpacted (or not bearing into dense undisturbed soils) as described earlier under

PREPARATION OF FOOTING AREAS should not exceed UBC values.



Foundation concrete should be placed in neat excavations with vertical sides, or the concrete

should be formed and the excavations properly backfilled as recommended for site fill.

SLABS-ON-GRADE:

To provide adequate support, concrete slabs-on-grade should bear on a minimum of 12 inches

of compacted soil or approved original ground soil. l11e final pad surfaces should be rolled to

provide smooth, dense surfaces upon which to place the concrete.

Slabs to receive moisture-sensitive coverings should be provided with a moisture vapor barrier.

This barrier may consist of an impermeable membrane. Two inches of sand over the membrane

will reduce punctures and aid in obtaining a satisfactory concrete cure. The sand should be

moistened just prior to placing of concrete.

CONSTRUCTION OBSERVATION:

All grading operations, including site clearing and stripping, should be observed by a

representative of the soils engineer. The presence of the soils engineer's field representative will

be for the purpose of providing observation and field testing, and will not include any

supervising or directing of the actual work of the contractor, his employees or agents. Neither

the presence of the soils engineer's field representative nor the observations and testing by the

soils engineer shall excuse the contractor in any way for defects discovered in his work. It is

understood that the soils engineer will not be responsible for job or site safety on this project,

which will be the sole responsibility of the contractor.

LIMITATIONS

C.H.J., Incorporated has striven to perform our services within the limits prescribed by our

client, and in a manner consistent with the usual thoroughness and competence of reputable soils

engineers and engineering geologists practicing under similar circumstances. No other

representation, express or implied, and no warranty or guarantee is included or intended by

virtue of the services performed or reports, opinion, documents, or otherwise supplied.


Page No. 14 Job No. 97599~3

This report reflects the testing conducted on the site as the site existed during the investigation,

which is the subject of this report. However, changes in the conditions of a property can occur

with the passage of time, due to natural processes or the works of man on this or adjacent

properties. Changes in applicable or appropriate standards may also occur whether as a result

of legislation, application, or the broadening of knowledge. TI1ercfore, this report is indicative

of only those conditions tested at the time of the subject investigation, and the findings of this

report may be invalidated fully or partially by changes outside of the control of C.H.J.,

Incorporated. This report is therefore subject to review and should not be relied upon after a

period of one year.

The conclusions and recommendations in this report are based upon observations performed and

data collected at separate locations, and interpolation between these locations, carried out for the

project and the scope of services described. It is assumed and expected that the conditions

between locations observed and/or sampled are similar to those encountered at the individual

locations where observation and sampling was performed. However, conditions between these

locations may vary significantly. Should conditions be encountered in the field, by the client

or any firm performing services for the client or the client's assign, that appear different than

those described herein, this fim1 should be contacted immediately in order that we might

evaluate their effect.

If this report or portions thereof are provided to contractors or included in specifications, it

should be understood by all parties that they are provided for information only and should be

used as such.

The report and its contents resulting from this investigation are not intended or represented to

be suitable for reuse on extensions or modifications of the project, or for use on any other

project.

I I-I I I I I I I I I I I I I I I I I

CLOSURE


We appreciate this opportunity to be of service and trust this report provides the infonnation

desired at this time. Should questions arise, please do not hesitate to contact this office.

BW /JJM/RJJ :jjm

Distribution: SunCal Companies ( 6)

Respectfully submitted,

C.H.J., INCORPORATED

Ben Williams, Senior Staff Engineer

1 1·~ y J( Martin, E.G. 1529

'ff/( Robert J. Jo Senior Vice President

he conc!1;sions and recommendation l"'\l"(.",,."('!11·1:~,-1 l'" ,, 1

-. i ~~ ··~· ..• r; :· ·!· 1~·~.~~\.' r:ct remain _,, ~· ,,• _, I .._. _ . 1 I I.\ ; , - I ,. t·· ·· ' l · ( ' I

V .l::.~ c•;\,,-r• ·'·;~·.· :·,,,_-., .. ,--·.: ;.,.:: t;r-.""'.:=i pr~sent t:11C, ...,, ....... 1 t., - ;•---·-·'· .• _j ·· ,.,, J l.;;

site cc~·::~~;:;.·:.':·, - ·~:r c ~· _:_: :· c:. , .. '~--~..:~-::·i vvhich have v~.,~:~.·:··/~.J c;ncc r:·'.:s ;·~.µ·'.)rt was originally ~.r0p1:,;·z~d. -i '.·:,J:·c~ore, this report shc~dd r:c t be L·:sci without the soils engineer addressing changes which may have 0-ecurred since the report was prepared.


REFERENCES


C.H.J., Incorporated, June 6, 1990, Preliminary Soils Investigation, Proposed Residential Development and Bridge Improvement, Tentative Tract No. 14326, Greenspot Road and Cone Camp Road, East Highlands Area, San Bernardino County, California, Job No. 881627-3.

Rasmussen, Gary S., March 30, 1990, Subsurface Engineering Geology Investigation, Tentative· Tract No. 14326, Immediately North of Greenspot Road and South of Oak Creek, Highland, California, Project No. 2652. J.

Suitt, Steven C., February 29, 1992, Feasibility-Level Geological Investigation, 45-Acre East Highland Parcel, San Bernardino County, California, Job No. 1CL105A.


AERIAL PHOTOGRAPHS REVIEWED


San Bernardino County Flood Control District, 1938, Black and white aerial photographs, photograph numbers N-2-14, N-2-15 and N-2-16.

San Bernardino County Flood Control District, November 10, 1955, Black and white aerial photographs, photograph numbers 7-71 and 7-72,

San Bernardino County Flood Control District, December 10, 1964, Black and white aerial photographs, photograph numbers 42 and 43.

San Bernardino County Flood Control District, December 3, 1965, Black and white aerial photographs, photograph numbers 100 and 101.

San Bernardino County Flood Control District, October 8, 1971, Black and white aerial photographs, photograph numbers 25, 26 and 27.

San Bernardino County Flood Control District, October 15, 1972, Black and white aerial photographs, photograph numbers 40 and 41.

San Bernardino County Flood Control District, January 21, 1978, Black and white aerial photographs, photograph numbers 115 and 116.

San Bernardino County Flood Control District, February 25, 1986, Black and white aerial photographs, photograph numbers 117 and 118.

San Bernardino County Flood Control District, July 1, 1991, Black and white aerial photographs, photograph numbers 133 and 134.

I I

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I

-Q~ 1.

./ ·'-7S'

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ENCLOSURE 1 SUBSURFACE INVESTIGATION MAP

C.H.J. INCORPORATED i ' TRACT NO. 14326

EAST SIDE OF PLUNGE CREEK NORTH OF GREENSPOT ROAD

HIGHLAND, CALIFORNIA PREPARED FOR

SUNCAL COMPANIES JOB NO.: 97599-3

-{ '? ,.. I ' I l:!l'i:... I-

I I I I I I I I I I I

-

60'

1640'

1635'

1630'

1625'

1620'

HORIZONTAL AND VERTICAL I SCALE 1"=5'-0"

I

I I I I I

50'

D e a d

Mn02

in gravel

40'

G r o v e

Possible subtle NW-trending fractures

Fine to coarse sand

111111

©

30' N46E

'A' soil horizon

12" concrete pipe, broken

N46W

SAND: fine to coarse, with gravel to 3", very pale brown (1 OYR 814), loose, damp to dry, well bedded to laminated; with interbeds of silty sand, fine to medium.

SAND: fine to coarse, with gravel to 4", very pale brown (10YR 814 · 7141, loose, damp, poorly bedded to well bedded.

SAMO: fine to coarse, with gravel to 4", very pale brown (10YR 814), loose, damp to moist. well bedded to laminated.

20'

©

©

©

10'

SAND: fine to medium, with gravel to 3". yellowish brown (1 OYR 514) to dark yellowish brown (IOYR 4/4), loose to slightly firm, moist. massive.

GRAVELLY SAND: fine to medium, clasts to 6". dark yellowish brown (1 OYR 4141. firm. moist. generally massive, some FeDx stain in sand beds.

SANDY GRAVEl: fine to coarse, clasts to 6", loose to firm. moist, massive.

Note: Extreme caving throughout trench

Logged by: JJM Drafted by: TMT

I ~--Dirt Road

o·

- 1640'

- 1635'

- 1630'

Weathered gneissic boulder

- 1625'

- 1620'

-

ENCLOSURE 2 GEOLOGIC TRENCH LOG C.H.J. INCORPORATED

TRACT NO. 14326 HIGHLAND, CALIFORNIA

PREPARED FOR SUNCAL COMPANIES

JOB NO.: 97599-3 DECEMBER 1997

Sheet 1of3


130'

1640'

1635'

-1630' ......

"'(

::::.. ~ 1625'

1620'

1615'

HORIZONTAL AND VERTICAL SCALE 1 "=5'-0"

120· N62E 11 o· \) 100' 90'

I N51E 80'

I

D e a d G r o v e

//////

©

©

Gravel

rA _ _ _ __ -·u©·o O: · O. · o' 5 · · · ".

. . - - 0 l) . - " ·o

. b' ... '(;; ..• • ·_. ·. . 'O

. -• .o .•.

-. -. 0 • "

'A' soil horizon

s.~ND: fine to coarse, with gravel to 3 • very pale brown (1 OYR 8/4), loose. d~mp. to dry, well bedded to laminated; wit~ mterbeds of silty sand, fine to med mm.

S~ND: fine to coarse, with gravel to 4 • very pale brown llOYR 8/4. 7/4), loose. damp, poorly bedded to well bedded.

•• - 0

© S~ND: fine to medium, with gravel to 3 ' yel!owish brown (1 OYR 5/41 to dark y~llowis~ brown (1 DYR 4/4), loose to shghtly firm, moist, massive.

® GRAVELLY SAND: fine to medium clasts to 6", dark yellowish broV-:n (l DY~ 4/4). firm, moist, generally massive. some FeDx stain in sand beds.

© SAN~Y GRAVEL: fine to coarse. clasts to 6 • loose to firm. moist. massive.

© S~JIJD: fine to coarse, with gravel to 4 • very pal~ brown (1 OYR 8/4), loose, damp to moist, well bedded to laminated.

Note: Extrem• caving throughout trench


BEND v ·-70' N46E

1640'

1635'

<: c::::i

1630' -......

~

1620'

1615'

ENCLOSURE 2 GEOLOGIC TRENCH LOG C.H.J. INCORPORATED.

TRACT NO .. 14326 HIGHLAND, CALIFORNIA


JOB NO.: 97599·3 DECEMBER 1997

Sheet 2 of 3


,200' 190' 180' 170'

1640'

D e a d

1635'

160' 150' 140'

N62'J---

G r o v e

13_D.'._ __

1640'

1635' ;;::::

t::>

: 1630' L.-.. -. _ ..... --"".""""_-~: .. ···-:_ .. __ ._7:".'". _ .... r:-·:~11-:'.".'.·:"".'.1\~--~"".''.·:"""_.'7-'•· .. _.""_: ... •·:_ ......... _._ ... · __ ·'.""_ • ...,_ ._ ... -._~:-_:::-..... ___ ~--7· --~"7""-·"""---""'.-·""'.-~-.. ~ •• -. __ ":"".\::-fi'.7-":.~::~·."7_,_:.·~-,:.-'""!'.•·~:::-r·:_~,---~-:·:."."'.'!'<~>7:::~::~----""' ... ~. ___ _, __ ._-~---_·7·_~~·~~~-~-. ~-=· :-.·-=·-=· .:;:µ"Jt;~CW~+;:~w4S:z1 ~ . -.- . ·, . . . --:-· ·.--y.. _. __ -, -=- 0 .

-· . 1630':

-. _. . : :;~Ji~, = ~:,n.~·:····:·-::· · ··.: · · · - ~:,·::;,;: 1525·~

--- ·o·-

.. -~-

-- <?

• - 0

·-·----

1..1..i 1625'

~·~~~~~~~~~~~~··z'-~-~~~~ ~ . -. ~----

_....;----·· ...:- . -- --~

. ___ ,,;_ -- ---~ ·.

__:. . .,---.- ..

1620' 1620'

1615'

HORIZONTAL AND VERTICAL SCALE 1 "=5'·0" I/Ill

©

'A' soil horizon

S~ND: fine to coarse, with gravel to 3 • very pale brown (10YR 8/4), loose, d~mp. to dry• well bedded to laminated; wit~ interbeds of silty sand, fine to medium.

s.~ND: fine to coarse, with gravel to 4 • very pale brown (10YR 8/4 . 7/4), loose, damp, poorly bedded to well bedded.

s.~ND: fine to coarse, with gravel to 4 • very pale brown (10YR 8/4) loose damp to moist, well bedded to ' ' laminated.

©

©

©

SAND: fine to medium, with gravel to 3", yel!owish brown (10YR 5/4) to dark y~llow1s~ brown (1 OYR 4/4), loose to shghtly firm, moist, massive.

GRAVELLY SAND: fine to medium clasts to 6'', dark yellowish bro~n 11 DY~ 4/4), firm, moist, generally massive, some FeOx stain in sand beds.

SAN~Y GRAVEL: fine to coarse, clasts to 6 • loose to firm, moist, massive.

Note: Extrem• caving throughout trench


1615'

ENCLOSURE 2 GEOLOGIC TRENCH LOG C.H.J. INCORPORATED

TRACT NO. 14326 HIGHLAND, CALIFORNIA


JOB NO.: 97599-3 DECEMBER 1997

Sheet3of3

i ' i -...

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