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1997-5331 G Street Address Category Serial # _ 5 3 3 ( Z (6 - r 7 Name Description I Plan ck. 4 Year r , COAST GEOTECHNICAL ' CONSULTING ENGINEERS AND GEOLOGISTS December 23, 1997 Rick Hettick P.O. Box 2607 Del Mar, CA 92014 Subject: RESPONSE TO JOHN POWELL AND ASSOCIATES /GRADING PLAN REVIEW Proposed Single- Family Residence ' Parcel 2, TPM 95 -249 Lone Hill Estates Olivenhain, California Reference: PRELIMINARY GEOTECHNICAL INVESTIGATION ' Proposed Single- Family Residence Lot 1, Portion of APN 264 - 451 -18, Lone Hill sf t6s Olivenhain, California L) U Prepared by Coast Geotechnical DEC 2 4 1997 ' Dated October 29, 1997 LNGlr Er: SING SERVICE - S CITY OF Ei�!vPR.IT� S Dear Mr. Hettick: This letter -report addresses the comments by John Powell and Associates, as well as our ' review of the proposed grading plan prepared by Pasco Engineering. ' Our review of the proposed grading plans for single lot development suggests that Pasco Engineering has included the recommendations presented in our Preliminary ' Geotechnical Investigation. ' 779 ACADEMY DRIVE • SOLANA BEACH • CALIFORNIA 92075 (619) 755 -8622 • FAX (619) 755 -9126 ' December 23, 1997 W.O. P- 271107 -1 Page 2 ' COMMENTS 1) A typographical error in our Preliminary Geotechnical report resulted in the t misnumbering of the APN. The corrected APN, Portion of APN 264 - 451 -18, is ' reflected in the attached copy of our Preliminary report. ' 2) The grading plans indicate an approximate 12.5 foot high 2:1 cut slope along the g P g ' eastern portion of the pad. A considerable amount of difficulty should be anticipated in grading, as well as overexcavation for the proposed garage. ' 3) It should be noted that the excavation characteristics of the metavolcanic rock are ' directly influenced by the degree of fracturing which varies considerably. It is possible that modifications to the building pad elevation may be required during ' the grading phase or possibly blasting may be necessary. 4) As indicated in the Preliminary Geotechnical report, the building pad should be ' undercut and capped with imported non - expansive fill deposits to a minimum t depth of 2.0 feet below the base of proposed footings. It is our understanding that the residence will be a single -story structure supported on stem wall footings ' with raised wood floors. The attached single -story garage will have a slab on grade. In this regard, the cap of imported fill deposits should be a minimum of 3.0 feet. Exterior concrete flatwork should be underlain by a minimum of 2.0 feet ' of imported granular deposits. P g P ' December 23, 1997 W.O. P- 271107 -1 ' Page 3 ' 5) As with any grading project, the geotechnical parameters used for foundation and slab design should be based on the characteristics of the actual soils used as compacted fill during grading. Revision of geotechnical design parameters may be necessary at the completion of grading and will be addressed in our Rough Grading Report. ' LIMITATIONS The findings and opinions presented herein have been made in accordance with generally ' accepted professional principals in the fields of geotechnical engineering. p p p p g No warranty ' is provided. If you have any questions regarding this letter, please contact our office. Reference to our job No. P- 271107 will help expedite a response to your inquiry. Respectfully submitted, Q� E 0� COAST GEOTECHNICAL Q'�` O" AI Mark Burwell Singhanet, P.E. Geologist �°CµO� Geotechnical Engineer t ®F CAL�� PRELIMINARY GEOTECHNICAL INVESTIGATION COAST GEOTECHNICAL ' CONSULTING ENGINEERS AND GEOLOGISTS ' October 29, 1997 Rick Hettick ' 4525 #7 Cove Drive Carlsbad, CA 92008 ' Subject: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Single- Family Residence Lot 1, APN 264 - 451 -18, Lone Hill Estates ' Olivenhain, California Dear Mr. Hettick: ' In response to your request and in accordance with our Proposal/Agreement dated October 10, 1997, we have performed a preliminary geotechnical investigation on the subject site for the proposed single- family residence. ' The findings of the investigation, laboratory test results and recommendations for foundation design are presented in this report. From a geotechnical point of view, it is our opinion that the site is suitable for the proposed development, provided the recommendations in this report are implemented I' during the design and construction phases. However, "hard rock" conditions and clayey soil deposits are present on the site which will require special consideration during the design and grading phase. ' If ou have an q uestions , lease do not hesitate to contact us at -8622. This y y q , p 755 ' opportunity to be of service is appreciated. Q�oFESSI . Respectfully submitted, ' COAST GEOTECHNICAL c� C7 CC Exp. 12 -31 -01 - Mark Burwell Ct�N�r ��`�° Vithayl Singhanet, P.E. Geologist 9 �t p� CAL�F4 Geotechnical Engineer ' 779 ACADEMY DRIVE • SOLANA BEACH • CALIFORNIA 92075 (619) 755 -8622 • FAX (619) 755 -9126 ' PRELIMINARY GEOTECHNICAL INVESTIGATION t Proposed Single - Family Residence Lot 1, APN 264 - 451 -18, Lone Hill Estates ' Olivenhain, California 1 Prepared For: ' Rick Hettick 4525 #7 Cove Drive Carlsbad, CA 92008 October 29, 1997 W.O. P-271107 7 7 ' Prepared By: COAST GEOTECHNICAL 779 Academy Drive ' Solana Beach, California 92075 I' ' TABLE OF CONTENTS VICINITY MAP INTRODUCTION 5 ' SITE CONDITIONS 5 PROPOSED DEVELOPMENT 5 SITE INVESTIGATION 6 ' LABORATORY TESTING 6 GEOTECHNICAL CONDITIONS 8 CONCLUSIONS 11 ' RECOMMENDATIONS 13 ' A. REMOVALS /GRADING/RECOMPACTION 13 B. FOUNDATIONS 14 ' C. SLABS ON GRADE (EXTERIOR) 15 D. RETAINING WALLS 16 E. DRIVEWAY 16 ' F. UTILITY LINE BACKFILL 17 G. DRAINAGE 17 H. OBSERVATIONS AND DENSITY TESTING 18 ' I. PLAN REVIEW 18 J. LIMITATIONS 18 1 1 APPENDICES APPENDIX A REGIONAL FAULT MAP LABORATORY TEST RESULTS TRENCH LOGS PLATE A PLATE B ' TOPOGRAPHIC MAP APPENDIX B GRADING GUIDELINES r VICINITY MAP 1 I ! Y G : 1 / / J' J/ J r ! f r i y f £. 1 f r f 5t 1 ...... ...... .... � /f. s R f P- 271107 SUBJECT PROPE TY ,t r f .. / ... 33 1 i i 4' !f f h i { 1 4 S i t r E /: _ E i! 3� t i t # h, f: .. D6Loiine sti et MW USA' ! i Mag 15.00 Scale 1:12,500 (at center) Thu Dec 18 16:42 1997 1 1000 Feet Secondary SR/Road/Hwy Ramp Population Center 1 200 Meters ' October 29, 1997 W.O. P- 271107 ' Page 5 ' INTRODUCTION This report presents the results of our geotechnical engineering investigation on the subject property. The purpose of this study is to evaluate the nature and characteristics of the surficial deposits underlying the property and their influence on the construction of a single- family residence. ' SITE CONDITIONS The subject property is located east of Lone Jack Road, along the southern terminus of ' Lone Hill Estates Court in the Olivenhain district city f Encinitas. The property tY P P rt3' ' includes approximately 2.4 acres of gently sloping hillside terrain. The lot descends to ' the southwest at an approximate grade of 15 percent to an adjacent undeveloped residential parcel. Relief on the site is a maximum of 44 vertical feet. Most of the site is covered by a sparse to moderate growth of shrubs. Drainage is ' generally by sheet flow to the southwest. PROPOSED DEVELOPMENT Preliminary grading plans for the development of the site were not available at the time ' of this study. However, it is our understanding the project includes the construction of a new single -story residence and attached garage in the central portion of the lot at the ' 472.5 foot elevation. The residence will be supported on stem wall footings with raised ' October 29, 1997 W.O. P- 271107 ' Page 6 ' wood floors. Maximum cuts and fills are anticipated to be on the order of 10.0 feet and 9.5 feet, respectively. t SITE INVESTIGATION Four backhoe exploratory trenches were excavated on the site to a maximum depth of ' 7.0 feet. Earth materials encountered were visually classified and logged by our field ' geologist. Sampling of earth materials was significantly impeded by near surface bedrock. Undisturbed and bulk samples of earth materials were obtained at selected intervals. ' Samples were obtained b driving a thin walled steel sampler into the desired strata P Y g P , where possible. The samples are retained in brass rings of 2.5 inches outside diameter ' and 1.0 inches in height. The central portion of the sample is retained in close fitting, waterproof containers and transported to our laboratory for testing and analysis. ' LABORATORY TESTING Classification ' The field classification was verified through laboratory examination, in accordance with ' the Unified Soil Classification System. The final classification is shown on the enclosed Exploratory Logs. ' Moisture/Density The field moisture content and dry unit weight were determined for each of the t ' October 29, 1997 W.O. P- 271107 ' Page 7 ' undisturbed soil samples. This information is useful in providing a gross picture of the soil consistency or variation among exploratory excavations. The dry unit weight was determined in pounds per cubic foot. The field moisture content was determined as a ' percentage of the dry unit weight. Both are shown on the enclosed Appendix A. ' Maximum Dry Density/Optimum Moisture Content The maximum dry density and optimum moisture content were determined for selected ' samples of earth materials taken from the site. The laboratory standard tests were in P rY ' accordance with ASTM D- 1557 -91. The results of the tests are presented in Appendix "A ". ' Expansion Test Expansion Tests were performed on the undisturbed soil samples. The samples were air dried for at least 24 hours, surcharged with a load of 125 pounds per square foot, and ' then inundated for 24 hours. The percent swell was recorded as a percentage of vertical ' rise to the original one -inch height. The results of the tests are tabulated in Table III, Appendix "A ". r ' October 29, 1997 W.O. P- 271107 r Page 8 ' Soil are generally classified according to their percent swell. Swell classifications are as follows: r Swell Potential Expansion 0 to 2 percent Low 2 to 6 percent Medium 6 to 10 percent High Above 10 percent Very High 1 GEOTECHNICAL CONDITIONS Based on a review of published geologic maps, the subject property is underlain at ' shallow depths by the Santiago Peak Volcanics. The bedrock, in general, is extremely ' hard although soft weathered zones above the dense rock do occur. The bedrock is generally overlain by clayey soil deposits which vary in thickness and isolated fill. A brief r description of the earth materials encountered on the site is discussed below. 1 Fill ' Isolated areas of fill were observed on the site. Rock and soil from the sewer line excavation are stockpiled along portions of the northern property line, and approximately 1.5 feet of fill was encountered in the vicinity of Test Pit No. 2. Isolated areas of fill are ' composed of clayey sand and rock, and are undocumented. 1 1 r ' October 29, 1997 W.O. P- 271107 ' Page 9 ' Soil/Colluvium Approximately 1.7 to 3.5 feet of soil was encountered in the Exploratory Trenches. The soil varies from reddish brown clayey sand to dark brown sandy clay. The clayey soils are ' highly expansive and vary in depth due to an undulating bedrock contact. Fractures within the upper portion of the bedrock are filled with clayey soil. ' Bedrock Locally, the site is underlain by metamorphosed volcanic rock commonly referred to as ' the Santiago Peak Volcanics. The bedrock is characterized b an undulating surface which g y g ' may be weathered and fractured up to 3.3 feet, or dense and hard along the surface. ' Below the weathered and fractured zone, the bedrock becomes increasingly dense and less fractured with depth. Expansive Soils Laboratory testing of representative samples suggest that the sandy clay soil has a t potential expansion in the high range. Ground Water ' No evidence of perched or high ground water tables were observed to the depth ' explored. However, it should be noted that the site is characterized by fractured metavolcanic rock and seepage problems may occur after development, as a result of t ' October 29, 1997 W.O. P- 271107 ' Page 10 ' drainage alterations and /or over - irrigation. In the event that seepage or saturated ground does occur, it has been our experience that they are most effectively handled on an individual basis. Liquefaction Potential ' Liquefaction is a process by which a fine sand mass loses its shearing strength completely ' and flows. The temporary transformation of the material into a fluid mass is often associated with ground motion resulting from an earthquake and high groundwater ' levels. ' Owing o the dense nature of the underlying metavolcanic rock and the anticipated depth g Y g P P ' to groundwater, the potential for seismically induced liquefaction and soil instability is ' considered very low to non - existent. ' Faults /Seismicity Based on a review of published geologic maps, no faults are located on or in the immediate vicinity of the site. The nearest active fault is the Rose Canyon Fault Zone located approximately 8.0 miles west of the site. Other active faults which could affect the site include the Coronado Bank, Elsinore, San Jacinto and San Andreas Faults. The proximity of these faults to the site is shown on the enclosed Regional Fault Map. Although the likelihood of round rupture on the site is remote it is almost a g g P certainty t ' October 29, 1997 W.O. P- 271107 Page 11 ' the property will be exposed to moderate to high levels of ground motion resulting from the release of energy, should an earthquake occur along the numerous known and unknown faults in the region. t CONCLUSIONS 1) The site is characterized by an undulating rock surface which is covered, in part, ' by variable depths of isolated fill and highly expansive soil, and weathered /fractured bedrock materials. The surficial deposits are not suitable for ' the support of foundations, concrete flatwork or fill deposits. PP P ' 2) Proposed grading should anticipate the removal and replacement of the surficial deposits as properly compacted fill. However, rock fragments greater than 6.0 ' inches should not be used as compacted fill. Fills should not have a rock content ' greater than 20 percent. If a considerable amount of rock is generated during grading, a rock disposal area should be delineated on the site or the rock should ' be exported. 3) Excavated materials will be composed of rock fragments and expansive clayey soils. I 'I , It is suggested that these materials be utilized in the key excavation and portions of the pad outside the building footprint. Imported granular fill deposits should be used for foundation support and concrete flatwork. t ' October 29, 1997 W.O. P- 271107 ' Page 12 ' 4) Preliminary concept plans suggest that a 9.5 to 10 foot cut will be required for a pad elevation of 472.5 feet along the eastern extent of the pad. The cut will extend to a depth of approximately 13 feet for the recommended overexcavation along the eastern extent of the structure. It should be noted that a 13 foot excavation may be beyond the capabilities of conventional grading equipment and blasting may be required. Our experience with recently constructed building pads ' underlain by metavolcanic rock suggests that a D -8 caterpillar can excavate the bedrock to a depth up to about 8.0 feet. However, the excavation characteristics of the bedrock varies and is directly nfluenced b the degree of fracturing. y y . g g ' Typically, the rock is "plucked out" along fractures by rippers. Cut slopes within ' the bedrock generally result in an uneven, irregular slope surface. ' 5) Due to the nature and characteristics of the metavolcanic rock, it is suggested that t the depth of proposed cuts, excavations and utility lines be considered during the design phase or blasting may be required during development. Additional recommendations and /or pad grade changes may be necessary in order to avoid i blasting, during grading. The proposed grade for the swimming pool should consider the depth of fill underlying the pool area such that the pool excavation ' will not require blasting. 6) Our experience with building pads underlain by fractured metavolcanic rock ' October 29, 1997 W.O. P- 271107 ' Page 13 ' suggest that varying degrees of seepage develop after construction. Post construction seepage and /or saturated ground conditions can adversely affect foundations and concrete flatwork. Therefore, special consideration should be ' provided for surface and subsurface drainage during the design and construction phases. Proposed subdrain locations include the key area and along the eastern ' overexcavation of the pad. Additional recommendations during the grading phase gP ' may be necessary in this regard. ' RECOMMENDATIONS O S ' Removals /Gradin ecom ap ction ' A minimum 15 foot wide key excavated (along the outside edge) a minimum of 1.0 foot into competent bedrock should be constructed along the base of the proposed fill slope. ' A subdrain should be constructed along the back of the key (See attached Key, Benching ' and Subdrain Detail, Plate A). All fill should be benched into the underlying competent rock units. The cut portion of the building pad should be undercut such that a minimum ' of 2.0 feet of imported granular fill is located beneath the base of proposed footings and ' exterior concrete slabs. Deeper granular fill deposits will be necessary beneath footings along the western portion of the residence. The overexcavation should extend a ' minimum of 10 lateral feet (5.0 feet along eastern extent of structure) beyond the ' building perimeter. A subdrain should be located along the lateral extent of the overexcavation (See Plate B). The existing earth deposits are generally suitable for reuse, ' October 29, 1997 W.O. P- 271107 ' Page 14 provided they are cleaned of all roots, vegetation, debris and rocks larger than 6.0 inches, and thoroughly mixed. Fill should be placed in 6.0 to 8.0 inch loose lifts, moistened as I' required to 2.0 -3.0 percent above optimum moisture, and compacted to a minimum of L' 90 percent of the laboratory maximum dry density. Fill and cut slopes should not exceed a gradient of 2:1 (horizontal to vertical). Additional recommendations will be presented ' should any unforeseen conditions be encountered during grading. Imported fill should ' be composed of granular deposits approved by this firm. Expansion tests should be performed on earth deposits used as compacted fill during the grading phase. Additional soil arameters for the design of foundations and slabs may be necessary. P g Y ' Foundations The following design parameters are preliminary in nature and may need revision or total ' re- design based on actual geotechnical conditions at the completion of rough grading. ' Footings for the proposed residence and attached garage should be a minimum of 12 inches wide and founded a minimum of 18 inches below the lower most adjacent grade ' at the time of foundation excavation. A 12 inch by 12 inch grade beam should be placed ' across the garage opening. The base of footings should be maintained a minimum horizontal distance of 10 feet from the face of the nearest slope. Footings should be ' reinforced with a minimum of four No. 5 bars, two placed along the top of the footing and two placed near the base. Footing recommendations provided herein are based upon underlying soil conditions and are not intended to be in lieu of the project ' structural n. engineer's design. g ' October 29, 1997 W.O. P- 271107 Page 15 I t Footings founded as recommended may be designed for a bearing value of 1500 pounds I per square foot. The foundation design parameters assume importation of granular 1 deposits for footing support. P g PP The bearing alue indicated above is for the total dead b e e d and frequently applied live loads. g q Y PP This value may be increased by 33 percent for short durations of loading, including the effects of wind and seismic forces. ' Resistance to lateral load may be provided by friction acting at the base of foundations and by passive earth pressure. A coefficient of friction of 0.35 may be used with dead- ' load forces. A passive earth pressure of 250 pounds per square foot, per foot of depth ' of granular fill penetrated to a maximum of 1500 pounds per square foot may be used. A pneumatic hammer may be required for retaining wall footings excavated into ' competent metavolcanic rock. The footing excavations should be reviewed by the ' geotechnical engineer prior to placement of forms. ' Slabs on Grade (F.xterior� ' Slabs on grade should be a minimum of 4.0 inches thick and reinforced in both directions with No. 3 bars placed 16 inches on center. Slabs should be underlain by a ' minimum 6.0 -inch sand blanket. Slabs including pool decking should be reinforced as ' indicated above and provided with saw cuts /expansion joints as recommended by the project structural engineer. All slabs should be cast over dense compacted non - expansive r October 29, 1997 W.O. P- 271107 Page 16 ' subgrades. Additional recommendations will be provided if expansive soils are used under the slab. i Retaining Walls Cantilever walls (yielding) retaining a 2:1 cut slope may be designed for an active - equivalent fluid pressure of 4.3 pounds per cubic foot. It is suggested that the wall be q P P P gg ' designed with a minimum of 12 inches of freeboard and a V -type interceptor drain to collect slope drainage and possible minor debris during periods of prolonged rainfall. ' Wall footings should be designed in accordance with the foundation g g e u dation design ' recommendations. All retaining walls should be provided with an adequate backdrainage ' system. The soil parameters assume a granular backfill compacted to a minimum of 90 percent of the laboratory maximum dry density. Driveway Previous testing suggests that onsite deposits have an R -value of 18. It is suggested that ' due to the cut /fill transition and clayey onsite deposits, the proposed driveway be capped ' by a minimum of 1.0 foot of imported granular deposits otherwise, a relatively thick Class 2 base section may be required. The driveway section recommendations will be ' presented in the rough grading report based on actual soil materials used in the subbase. ' However, it should be noted that the subbase section should be compacted to a relative density of 95 percent and the pavement section should be protected from adjacent water sources such as P lanted areas. ' October 29, 1997 W.O. P- 271107 ' Page 17 ' Utility Line Backfill We recommend that all utilities be bedded in clean sand to at least one foot above the top of the conduit. The bedding should be flooded in place to fill all the voids around the conduit. Imported granular material compacted to at least 90 percent relative II compaction may be utilized for backfill above the bedding. Care should be exercised such that backfilled utility nes do not become conduits t b e u s for the migration of subsurface i water. Drainage Specific drainage patterns should be designed th I' p g p by e project civil engineer. However, in general, pad water should be directed away from foundations and around the structure to a suitable discharge location designed by the engineer. Roof water should be collected ' and conducted to area drains, via non - erodible devices. Pad water should not be allowed ' to pond or flow onto slopes in an uncontrolled manner. A minimum 1.0' high compacted berm should be provided along the top of all fill slopes. Due to the pervious ' nature of granular deposits, vegetation adjacent to foundations should be avoided. If ' vegetation in these areas is desired, sealed planter boxes or drought resistant plants should be considered. Other alternatives may be available, however, the intent is to ' reduce moisture from migrating into foundation subsoils. Fill slopes should be planted ' with drought resistant vegetation. Irrigation should be limited to that amount necessary to sustain plant life. ' October 29, 1997 W.O. P- 271107 ' Page 18 Observations and Density Testing Structural footing excavations should be observed by a representative of this firm, prior I ' to the lacement of steel. Fill should be laced while a representative of this firm is P P P ' present to observe and test. Plan Review ' As previously indicated, grading plans were not available at the time of this study. A copy of the preliminary grading plans should be reviewed by this office when available. ' Additional recommendations may be necessary. r5. ' ' LIMITATIONS This report is presented with the provision that it is the responsibility of the owner or the ' owner's representative to bring the information and recommendations given herein to ' the attention of the project's architects and /or engineers so that they may be incorporated into plans. If conditions encountered during construction appear to differ from those described in this report, our office should be notified so that we may consider whether modifications are needed. No responsibility for construction compliance with design concepts, specifications or recommendations given in this report is assumed unless on -site review ' is performed during the course of construction. ' October 29, 1997 W.O. P- 271107 ' Page 19 ' The subsurface conditions, excavation characteristics and geologic structure described herein are based on individual exploratory excavations made on the subject property. t The subsurface conditions, excavation characteristics and eolo is structure discussed g g ' should in no way be construed to reflect any variations which may occur among the exploratory excavations. Please note that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature and other factors not evident at the time measurements were made ' and reported herein. Coast Geotechnical assumes no responsibility for variations which ' may occur across the site. ' The conclusions and recommendations of this report apply as of the current date. In time, however, changes can occur on a property whether caused by acts of man or nature ' on this or adjoining properties. Additionally, changes in professional standards may be ' brought about by legislation or the expansion of knowledge. Consequently, the conclusions and recommendations of this report may be rendered wholly or partially ' invalid by events beyond our control. This report is therefore subject to review and ' should not be relied upon after the passage of two years. ' The professional judgments presented herein are founded partly on our assessment of the technical data gathered, partly on our understanding of the proposed construction ' and partly on our general experience in the geotechnical field. Our engineering work r October 29, 1997 W.O. P- 271107 Page 20 and the judgments given meet present professional standards. However, in no respect do we guarantee the outcome of the project. r I I I � APPENDIX A i i i 1 r e ye rr. y 4 t i� r a� - i f , 1p 1 l _T I i d�1 / (•may .,` \ZA-a � � i `. "( � � � ♦♦ `•' fit 1 ' ' _.. i ; e . - � •�' ,`jy` —t !) t - �# � � o a � �+ ` � � � 1 ham' - • r+ I ! , Vv J ; ' ��. 9 if /,. `'�i i<•I. d.� ' t i ;ice i�•• ;+1• � /^/ :; Ivry/ l�: -/: f � 3.1 / 1 1z •`�yyl��n i F 'I • ' � �!j+ ` � / s I ?y 14 � ��� "• .\ � >_�_ :i � �' y f �.N� � Z� ! \ ?. v Ste' i - ��. — ~� — J 4 y,` j/ / ./. K , l • ♦. 7' �� Pa ��� ! � ' � � • 'tom : � - \ j , I � : r ._���_�... ��/• �� �i t is , + § ` � � t•. , 1 • � � � � = 1 I ( ,� mi � �:�� , � -�� ,�,•� .�-,> � � � �/ + �.�!; • \?� :�•�� 1 �,t..j /� a te" �i �'�` �'- ��� j� �. r ^k'1• �/ � i � � / .rte f�-/ 4 ;� �� bill Y � q �p� C / ' % g' 1 � � r ( /,• � yl / + Y,"^' � � •/ �� r C I a'' J - (y ��r� • ; __ �/ J u �n // + 1 ' LABORATORY TEST RESULTS ' TABLE I Maximum Dry Density and Optimum Moisture Content ' (Laboratory Standard ASTM D- 1557 -91 ' Sample Max. Dry Optimum Location Density (pcf) Moisture Content T -2 @ 1' -3' 117.2 14.0 ' TABLE II Field Dry Density and Moisture Content ' Sample Field Dry Field Moisture Location Density Content ' cf T -1 @ 1.0' 82.4 8.8 ' T -1 @ 1.5' Lost Sample T -2 @ 1.5' 101.2 13.5 ' T -2 @ 4.0' 102.4 14.2 T -2 @ 5.0' 110.2 16.9 t ' TABLE III Expansion Test Sample ' Location Soil Type Swell T -2 @ 5.0' Natural 16% ' P- 271107 1 1 0 �o i � o O J y � W � o LLI z d •� � 1 _ 1 3 � I+1 � • I �J w o y w ' a z o w ' U aoQ O o ° �d C7 z 3 z m z ' z Q J O � � U o v O 1 1 1 o u ' � n O � b O U V n ,z7 I 11 W Q O O V o �- ' W o o .0 - 1 _a x �" z C ° ` d o CIO ' C) o 0 U ¢ �? 3 C7 z z Q z OL ' O V I IT D 1 1 0 0 (n 1 m 3 1 � a v CD v► . 0 a�i o I— h x 1 0 V cn m � N W o 0 CL 1 1 O U 1 �o U< N 1 Q o N 0 0 0 3 o N C� Z w � In JC ' 7 Z c 1 v p 1 1 1 o. !. ~ 0 ' o o T v .co O 0 o a� J � a� � o y O / i U ► j 1 u m o N W o F� p ' F — U2 U � U O W I o O o 1 - a o x Un U i w? 3 z ' z Q J N u z 1 U o ; - 1 -------------- F I L L SLOPE --------------- PROJECT 1 0 1 LINE ---------------- FROM TO OF SLOPE TO COMPETENT MATERIAL ----------- --------- --- EXISTING ---------- GROUND SURFACE REMOVE UNSUITABLE ' � - -__ _ - _�__ = MATERIAL BENCH % MIN. V'MIN. 15' MIN KEY LOWEST DEPTH BENCH (KEY) 0 MIN. OVERLAP 3/4 CLEAN GRAVEL 'o L 6 MIN. (Iftl4ft. MIN.) COVER 4* . 0 1 1 4 0 NON - P 5.�= PERFORATED 4 NONPERFORATED PIPS PIPE PIPE LATERAL TO SLOPE FACE AT 100 MIN INTERVALS mm FILTER FABRIC ENVELOPE (MIRAFI 4 MIN 140N OR APPROVED BEDDING EOUIVALENT)* SUBDRAIN TRENCH DETAIL KEY, BENCHING AND SUBDRAIN DETAIL PLATE A 1 1 � w a F H a w W o p °: w I w a a H i F 1 ° a o, ° a 41 V I� z z A E1 a H i 0 '� o 1 0 0 to z °I w q w " I I a a LO 1- N E a OO FI Q p o o o F lad I 14 :ppd a v°o°� ° H 1 � ��� a �a�l 3 U � � b hi w a w f F W � s x a ' U � H a 1 1 1 i i y / w --J V vi ) A W LL /' c0 � pp Ld vi_vi / Q r co / CL OOQO \ (D ool / U ti v A� �— I o5b Go cb a / a o .-+ / / CL 14 ` a l e i "o OD V) looll LAJ LL l0 — I x= I I / Y ' o O .9l .9L W Z - � p w Q i -- o I > x I� C V— W . L �` O �� -- p i-. L Ln p, W v Q � H a v � L r , 1 1 1 1 1 1 � APPENDIX B i i i i ' GRADING GUIDELINES ' Grading should be performed to at least the minimum requirements of the governing agencies, Chapter 70 of the Uniform Building Code, the geotechnical report and the guidelines presented below. All of the guidelines may not apply to a specific site and ' additional recommendations may be necessary during the grading phase. ' Site Clearing Trees, dense vegetation, and other deleterious materials should be removed from the ' site. Non - organic debris or concrete may be placed in deeper fill areas under direction of the Soils engineer. ' Subdrainage ' 1. During grading, the Geologist and Soils Engineer should evaluate the necessity of placing additional drains (see Plate A). ' 2. All subdrainage systems should be observed by the Geologist and Soils Engineer during construction and prior to covering with compacted fill. ' 3. Consideration should be given to having subdrains located by the project surveyors. Outlets should be located and protected. ' Treatment of Existing Ground 1. All heavy vegetation, rubbish and other deleterious materials should be disposed of off site. 2. All surficial deposits including alluvium and colluvium should be removed unless otherwise indicated in the text of this report. Groundwater existing in the alluvial areas may make excavation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months. ' 3. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards. Fill Placement ' 1. Most site soil and bedrock may be reused for compacted fill; however, m Y p , some special processing or handling may be required (see report). Highly organic or ' contaminated soil should not be used for compacted fill. ' (1) ' 2. Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts not to exceed six inches in thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a horizontal plane, unless otherwise found acceptable by the Soils Engineer. ' 3. If the moisture content or relative density varies from that acceptable to the Soils engineer, the Contractor should rework the fill until it is in accordance with the ' following: a) Moisture content of the fill should be at or above optimum moisture. ' Moisture should be evenly distributed without wet and dry pockets. Pre - watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. ' b Each six inch layer h ye should be compacted to at least 90 percent of the ' maximum density in compliance with the testing method specified by the controlling governmental agency. In this case, the testing method is ASTM Test Designation D- 1557 -91. ' 4. Side -hill fills should have a minimum equipment -width key at their toe excavated through all surficial soil and into competent material (see report) and tilted back ' into the hill (Plate A). As the fill is elevated, it should be benched through surficial deposits and into competent bedrock or other material deemed suitable by the Soils Engineer. 5. Rock fragments less than six inches in diameter may be utilized in the fill, provided: ' a) They are not placed in concentrated pockets; ' b) There is a sufficient percentage of fine - grained material to surround the rocks; ' c) The distribution of the rocks is supervised by the Soils Engineer. 6. Rocks greater than six inches in diameter should be taken off site, or placed in ' accordance with the recommendations of the Soils Engineer in areas designated as suitable for rock disposal. 7. In clay soil large chunks or blocks are common; if in excess of six (6) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitable methods should be used to break the up blocks. ' (2) ' 8. The Contractor should be required to obtain a minimum relative compaction of 90 percent out to the finished slope face of fill slopes. This may be achieved by ' either overbuilding the slope and cutting back to the compacted core, or by direct compaction of the slope face with suitable equipment. ' If fill slopes are built "at grade" using direct compaction methods then the slope construction should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor ' should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be back rolled approximately every 4 feet vertically as the slope is built. Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope. In addition, if a method other than over building and cutting back to the compacted core is to be employed, slope compaction testing during construction ' should include testing the outer six inches to three feet in the slope face to determine if the required compaction is being achieved. Finish grade testing of the slope should be performed after construction is complete. Each day the ' Contractor should receive a copy of the Soils Engineer's "Daily Field Engineering Report" which would indicate the results of field density tests that day. ' 9. Fill over cut slopes should be constructed in the following manner: a) All surficial soils and weathered rock materials should be removed at the ' cut -fill interface. b) A key at least 1 equipment width wide (see report) and tipped at least 1 ' foot into slope should be excavated into competent materials and observed by the Soils Engineer or his representative. ' c) The cut portion of the slope should be constructed prior to fill placement to evaluate if stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior to cut ' excavation. 10. Transition lots (cut and fill) and lots above stabilization fills should be capped with a four foot thick compacted fill blanket (or as indicated in the report). 11. Cut pads should be observed by the Geologist to evaluate the need for ' overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones,and /or due to differing expansive potential of materials beneath a structure. The overexcavation ' should be at least three feet. Deeper overexcavation may be recommended in some cases. (3) ' 12. Exploratory backhoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Grading Observation and Testing 1. Observation of the fill placement should be provided by the Soils Engineer during the progress of grading. 2. In general, density tests would be made at intervals not exceeding two feet of fill height or every 1,000 cubic yards of fill placed. This criteria will vary depending on soil conditions and the size of the fill. In any event, an adequate number of ' field density tests should be made to evaluate if the required compaction and moisture content is generally being obtained. ' 3. Density tests may be made on the surface material to receive fill, as required by the Soils Engineer. 4. Cleanouts, processed ground to receive fill, key excavations,subdrains and rock disposal should be observed by the Soils Engineer prior to placing any fill. It will ' be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for observation. ' 5. A Geologist should observe subdrain construction. 6. A Geologist should observe benching prior to and during placement of fill. ' Utility Trench Backfill Utility trench backfill should be placed to the following standards: 1. Ninety percent of the laboratory standard if native material is used as backfill. ' 2. As an alternative, clean sand may be utilized and flooded into place. No specific relative compaction would be required; however, observation, probing, and if ' deemed necessary, testing may be required. 3. Exterior trenches, paralleling a footing and extending below a 1:1 plane projected ' from the outside bottom edge of the footing, should be compacted to 90 percent of the laboratory standard. Sand backfill, unless it is similar to the inplace fill, should not be allowed in these trench backfill areas. ' Density testing along ith robin should be accomplished to verify g probing p the desired results. ' (4) PASCO ENGINEERING, INC. 535 NORTH HIGHWAY 101, SUITE A SOIANA BEACH, CA 92075 Z,' Z 4 ' `T (619) 259 -8212 WAYNE A. PASCO FAX (619) 259 -4812 R.C.E. 29577 November 19, 1997 PE 769 deb rip -rap► di % • •�t,vr. �h� s City of Encinitas 505 So. Vulcan Avenue d, x . 6 0 % + 40 414! r.,0 ti Encinitas, CA 92024 5 Attn: Blair Knoll RE: HYDROLOGY REPORT FOR HETTICK RESIDENCE GRADING PLAN Dear Mr. Knoll: The purpose of this letter is to address the impacts of storm runoff on the grading as proposed on the above mentioned grading plan. The site is situated near a natural ridge 1 ie id �h unne i it of the drainage area tributary to the site. ./ ov -� D Based on the attached calculations, it isr r� t at the drainage structures specified on the above mention tp� &uate to intercept, contain and convey Qloo to the indicated pom �Edi6lt�61-gS If you have any questions or comments regarding the above, please do not hesitate to contact us. Very truly yours, PASCO ENGINEERING, INC. Q �pFESS104� A. Wayne Pasco President -- RCE 29577 �� -C/) O �� No.29577 MS/WP /js c�Tygrv�Q • Exp. 3/31/99 Attachments J'� c l v o- � CO ******************************************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 1985,1981 HYDROLOGY MANUAL (c) Copyright 1982 -92 Advanced Engineering Software (aes) Ver. 1.3A Release Date: 3/06/92 License ID 1388 Analysis prepared by: Pasco Engineering, Inc. 535 North Hwy. 101, Suite A Solana Beach, CA 92075 Ph. (619) 259 -8212 Fax (619) 259 -4812 * * * * * * * * * * * * * * * * * * * * * * * * ** DESCRIPTION OF STUDY * * * * * * * * * * * * * * * * * * * * * * * * ** * Hydrology Analysis * Hettick Residence, 100 year storm * 11 -19 -97 ms ******************************************* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** FILE NAME: 769.DAT TIME /DATE OF STUDY: 10: 8 11/19/1997 ---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: ---------------------------------------------------------------------------- 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6 -HOUR DURATION PRECIPITATION (INCHES) = 3.100 SPECIFIED MINIMUM PIPE SIZE(INCH) = 4.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE _ .95 SAN DIEGO HYDROLOGY MANUAL "C"- VALUES USED NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED ********************************************* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** FLOW PROCESS FROM NODE 31.00 TO NODE 30.00 IS CODE = 21 ---------------------------------------------------------------------------- » »> RATIONAL METHOD INITIAL SUBAREA ANALYSIS « «< SOIL CLASSIFICATION IS "D" RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500' NATURAL WATERSHED NOMOGRAPH TIME OF CONCENTRATION WITH 10- MINUTES ADDED = 11.70(MINUTES) INITIAL SUBAREA FLOW - LENGTH = 300.00 UPSTREAM ELEVATION = 499.00 DOWNSTREAM ELEVATION = 476.00 ELEVATION DIFFERENCE = 23.00 100 YEAR RAINFALL INTENSITY(INCH /HOUR) = 4.721 SUBAREA RUNOFF(CFS) = 1.59 TOTAL AREA(ACRES) _ .75al TOTAL RUNOFF(CFS) = 1.59 I FLOW PROCESS FROM NODE 30.00 TO NODE 20.00 IS CODE = 3 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA<<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW) ««< --------------- -- DEPTH OF FLOW IN 9.0 INCH PIPE IS 3.7 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 9.4 ✓ UPSTREAM NODE ELEVATION = 476.00 DOWNSTREAM NODE ELEVATION = 466.00 FLOWLENGTH(FEET) = 125.00 MANNING'S N = .013 ESTIMATED PIPE DIAMETER(INCH) = 9.00 NUMBER OF PIPES PIPEFLOW THRU SUBAREA(CFS) = 1.59V TRAVEL TIME(MIN.) .22 TC(MIN.) = 11.92 FLOW PROCESS FROM NODE 30.00 TO NODE 20.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 11.92 RAINFALL INTENSITY(INCH/HR) = 4.66 TOTAL STREAM AREA(ACRES) = .75 PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.59 FLOW PROCESS FROM NODE 21.00 TO NODE 20.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< ---------------------------------------------------------------------------- SOIL CLASSIFICATION IS "D RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 INITIAL SUBAREA FLOW-LENGTH = 240.00 UPSTREAM ELEVATION = 472.50 DOWNSTREAM ELEVATION = 466.00 ELEVATION DIFFERENCE = 6.50 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 13.004 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.409 SUBAREA RUNOFF(CFS) .89 TOTAL AREA(ACRES) .45 O ' TOTAL RUNOFF(CFS) .89 FLOW PROCESS FROM NODE 21.00 TO NODE 20.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ---------------------------- - - - --- TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = 13.00 RAINFALL INTENSITY(INCH /HR) = 4.41 TOTAL STREAM AREA(ACRES) = .45 PEAK FLOW RATE(CFS) AT CONFLUENCE _ .89 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH /HOUR) (ACRE) 1 1.59 11.92 4.664 .75 2 .89 13.00 4.409 .45 RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH /HOUR) 1 2.44 11.92 4.664 2 2.40 13.00 4.409 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 2.44 Tc(MIN.) = 11.92 TOTAL AREA(ACRES) = 1.20 ********************************************* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** FLOW PROCESS FROM NODE 11.00 TO NODE 10.00 IS CODE = 21 --------------------------------------------------------------------------- » » >RATIONAL METHOD INITIAL SUBAREA ANALYSIS ««< SOIL CLASSIFICATION IS "D" RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 NATURAL WATERSHED NOMOGRAPH TIME OF CONCENTRATION WITH 10- MINUTES ADDED = 11.89(MINUTES) INITIAL SUBAREA FLOW - LENGTH = 338.00 UPSTREAM ELEVATION = 495.00 DOWNSTREAM ELEVATION = 470.00 ELEVATION DIFFERENCE = 25.00 100 YEAR RAINFALL INTENSITY(INCH /HOUR) = 4.673 SUBAREA RUNOFF(CFS) _ .55 TOTAL AREA(ACRES) _ .26 TOTAL RUNOFF(CFS) _ .55 FLOW PROCESS FROM NODE 11.00 TO NODE 10.00 IS CODE = 1 --------------------------------------------------------------------------- » » >DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE «« < TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 11.89 RAINFALL INTENSITY(INCH/HR) = 4.67 TOTAL STREAM AREA(ACRES) = .26 PEAK FLOW RATE(CFS) AT CONFLUENCE .55 FLOW PROCESS FROM NODE 21.00 TO NODE 10.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< --------------- - - - - -- SOIL CLASSIFICATION IS "D" RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 INITIAL SUBAREA FLOW-LENGTH = 160.00 UPSTREAM ELEVATION = 472.50 DOWNSTREAM ELEVATION = 470.00 ELEVATION DIFFERENCE = 2.50 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 12.754 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.465 SUBAREA RUNOFF(CFS) .46 TOTAL AREA(ACRES) .23 TOTAL RUNOFF(CFS) .46 FLOW PROCESS FROM NODE 21.00 TO NODE 10.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = 12.75 RAINFALL INTENSITY(INCH/HR) = 4.46 TOTAL STREAM AREA(ACRES) = .23 PEAK FLOW RATE(CFS) AT CONFLUENCE .46 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 .55 11.89 4.673 .26 2 .46 12.75 4.465 .23 RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) 1 .99 11.89 4.673 2 .98 12.75 4.465 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) .99 Tc(MIN.) = 11.89 TOTAL AREA(ACRES) .49 FLOW PROCESS FROM NODE 42.00 TO NODE 41.00 IS CODE = 21 --------------------------------------------------------------- » »> RATIONAL METHOD INITIAL SUBAREA ANALYSIS« «< ------------------- - - - - -- ------- - - - - -- --------------- SOIL CLASSIFICATION IS "D" RURAL DEVELOPMENT RUNOFF COEFFICIENT = .4500 INITIAL SUBAREA FLOW - LENGTH = 100.00 UPSTREAM ELEVATION = 470.40 DOWNSTREAM ELEVATION = 469.40 ELEVATION DIFFERENCE = 1.00 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 11.700 100 YEAR RAINFALL INTENSITY(INCH /HOUR) = 4.720 SUBAREA RUNOFF(CFS) _ .21 TOTAL AREA(ACRES) _ .10 TOTAL RUNOFF(CFS) _ .21 FLOW PROCESS FROM NODE 41.00 TO NODE 40.00 IS CODE = 3 ---------------------------------------------------------------------------- » » >COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA « «< » » >USING COMPUTER - ESTIMATED PIPESIZE (NON- PRESSURE FLOW) « «< -------------------------- ------ ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 4.000 DEPTH OF FLOW IN 4.0 INCH PIPE IS 1.1 INCHES PIPEFLOW VELOCITY(FEET /SEC.) = 11.1 UPSTREAM NODE ELEVATION = 468.40 DOWNSTREAM NODE ELEVATION = 458.50 FLOWLENGTH(FEET) = 20.00 MANNING'S N = .013 ESTIMATED PIPE DIAMETER(INCH) = 4.00 NUMBER OF PIPES = 1 PIPEFLOW THRU SUBAREA(CFS) _ .21 TRAVEL TIME(MIN.) _ .03 TC(MIN.) = 11.73 ------------------ - - - - -- END OF STUDY SUMMARY: PEAK FLOW RATE(CFS) _ .21 Tc(MIN.) = 11.73 TOTAL AREA(ACRES) _ .10 ---------------------- - - - - -- END OF RATIONAL METHOD ANALYSIS Prepared by Pasco Engineering 11/19/97 PE 769 AREA DRAIN CAPACITY CALCULATIONS CALCULATE CAPACITY OF AREA DRAINS. FORMULA: Qcap = 3.0(P)(D ^1.5) / 2. DIVISION BY 2 ACCOUNTS FOR GRATE. PERIMETER AVAIL HW GRATE FACTOR Q100 (CFS) P (FT) D (FT) 2* CAPACITY (CFS) INLET TYPE 0.21 4.00 0.50 3.00 1.41 12" x 12" BROOKS CB 1.59 4.00 1.00 3.00 4.00 12" x 12" BROOKS CB CALCULATE DISCHARGE OF PVC OUTLET PIPE. CONSIDERED AS ORIFICE FORMULA: Q = (C)(A)((2)(32)(3)) ^0.5. 3 FEET OF AVAIL. HEADWATER DEPTH HW DEPTH LOSS COEF. AREA DISCHARGE 3.00 0.60 0.20 1.63 6" PVC SDR -35 2.00 0.60 0.44 2.98 9" PVC SDR -35 gjly A'fr„.i i L L I " sm c J J N N N N t q q V q N m m 7 \� I I C} .N v —m v\ °D v 0 t ' r to N + r- 1�} +Dr n ° F0Cn © q J D _ L _ t 0 t O O T L — 4 m :p L = L N L E CD cli 0. a N N 4 m — W M M' 0_. + }" n U 0 L g y p ! L L g Q m 4 Y O. L U y *L0 k I �„ qt L U O N V O U O) U O) 01 \ C N p cc N U �p E U m * — k;- I C� 1F LOd m�� ^ m � " �o n Go �r n t\ e} ° L O m n. M E r- o i. « -) O y B(I ' O L F. L U q C-4 O� m Y E t 1' 0 .9 O N a op 0 10 k i n N L m �� Z U > >. L J -- q O N 4- H m 00M g 0 c Y O Z CID q 0 lid;! a + J o: o U— < o' W f-- — 0— S O O t CL s7' W I H > 0. w G: —1- ,. OO I c� I { q I cn .-..� N m >. q S con i < \ O 1 1 I m v n " ?� I +q^� L q W J H U1% � E 0 U 1 / -02 0 U — S E m O U L 6 U tt1 D\ .0 ( D s ^q0 ;; w C to n 0 — .°- O 8 c O � c O fO c )n ~ I I m ©c ( I MF 0 0 I WN a 0 E O /a) o ° c �— LL U U +� _— c O CL I'. IIciG Odm )O W U� vio O �0 y I. + > N — c c m . F' Ov Gijl LNG %p — in N a)o� Cim „IL ble: q O t + c r 0 L u o C\ <v a 0 0 0 0 Oa_�.a� E U N U Y m E-F-F F'F - - - - -- q mi I � I .C1 �. m U N N .- N v O )n u'1 1[l 1.: O Ip �.a L 4- a L — O C'4 ^ N N CL ^fir u i1 I !if 1y, t� 7 91 M II1� � I w 4.7 UN C k..-7 CD cn cn C,u- cn o u -7� Lr�- - CN LO C5 C14 0 C cc C:) CN -j L I r , .1. U,>CN I CN JJ .41 . 0 < CLI p 7. w < < , < a v 0 Ltl CD 0 o C) 0 00 Lu Lf\ n o :z LL- < < 0 C) V) C: 0 LL- < C> Lli C:;o O u z < < CD m z Im CL- 0 0 C Uj -j V) u � U- w z N 11-A-7 r \ I �� � Q � \ �\� \ '1 \ \ \ o� E XIST �, a PARC 1 Al lip v 81 3'37 m 15 .12' Tr`�, WAY E \ \ 87 ,126 S.. T C 3 88,394 S.F G Lr \ 2 \ \ Q \ a C. S.� \ ?60 F NE D26 S. . \R f \ wa`,� > \ Lo.� P I F l _ \ l I N 8°15' O W�0 138 4)01' \ - W I _-_ �--- w �EX4T 8" AC TEAM IN \ 1 COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS ' March 24, 1998 ' Rick Hettick ' P.O. Box 2607 Del Mar, CA 92014 Subject: ROUGH GRADING REPORT ' Proposed Single- Family Residence Parcel 2, Map No. 17967, Lone Hill Estates APN 264 - 451 -18 ' Olivenhain, California References: Please refer to page 12 Dear Mr. Hettick: ' In response to your request, we have performed field observations and testing during the rough grading phase on the above referenced property. The results of our density tests ' and laboratory testing are presented in this report. Based on the results of our testing, it is our opinion that the fill was placed in an ' adequate manner and compacted to a minimum of 90 percent of the laboratory maximum dry density. ' If you have any questions, please do not hesitate to contact us at (619) 755 -8622. This opportunity to be of service is greatly appreciated. t Respectfully submitted, @FLCFESS / j � a ' COAST GEOTECHNICAL � SIIV�,� 0 782 2tn M Exp. 12 -31 -0 i m Mark Burwell ` 6) �� „� Vitha a 4 Singhanet, P.E. ' Geologist °4'��G��� Geotechnical Engineer ' 779 ACADEMY DRIVI: • SOLANA BEACH • CALIFORNIA 92075 (619) 755 -8622 • FAX (619) 755 -9126 ROUGH GRADING REPORT ' Proposed Single - Family Residence Parcel 2, Map No. 17967, Lone Hill Estates APN 264 - 451 -18 ' Olivenhain, California 1 Prepared for: ' Rick Hettick P.O. Box 2607 Del Mar, CA 92014 March 24, 1998 ' W.O. G- 271107 ' Prepared by: COAST GEOTECHNICAL 779 Academy Drive ' Solana Beach, California 92075 March 24, 1998 W.O. G- 271107 ' Page 3 ' INTRODUCTION This report presents the results of our observations and field density testing on the ' subject property. The project included the cutting and filling of a southwesterly sloping t lot, in order to develop a level building pad. The results of our density tests are presented on Table I. The approximate locations of these tests are shown on the ' enclosed Gradin g Plan. ' LABORATORY TEST DATA The laboratory standard for determining the maximum dry density was performed in ' accordance with ASTM D 1557 -91. Field density tests were performed in accordance with ' ASTM D 1556. The results of the laboratory maximum dry density, for the soil types used as compacted fill on the site, is summarized below: Maximum ' Dry Density Optimum Soil Type Description (p.c.f.) Moisture (%) ' A Mixture of on -site 117.2 14.0 soils, brown silty, sandy, gravelly ' clay with rock B Import: Brown silty 126.0 10.9 ' and fine - grained sand, slightly clayey ' C Import: Tan to brown 125.0 10.0 silty and medium - grained ' sand, trace of clay March 24, 1998 W.O. G- 271107 Page 4 GEOTECHNICAL CONDITIONS Surficial deposits include minor fill and clayey soil deposits. Underlying the surficial ' deposits, metamorphosed volcanic rock commonly referred to as the Santiago Peak Volcanics is present. The bedrock is characterized by an undulating surface of hard rock and weathered zones. Imported material, consisting of silty and fine - grained sand, was 1 used in the building pad. ' EXPANSIVE SOILS Most of the highly expansive materials such as clayey soil deposits were used in the key ' and slope area, and lower portions of the pad. Imported materials were used in the t building pad. However, the cap of relatively non - expansive fill is limited to approximately 3.0 feet. Previous testing and evaluation of the lower clayey fill deposits in the western ' portion of the building pad suggests these deposits have a potential expansion that varies ' from a medium to high range. DISCUSSION ' The grading contractor on this project was Mike Scott Grading. The following is a discussion of the general grading operations, as they were performed on the site: ' 1) All surface deleterious material was removed and disposed of off -site, prior to the placement of fill. ' March 24, 1998 W.O. G- 271107 ' Page 5 ' 2) A minimum 15 foot wide key was excavated along the base of the proposed fill slope into the underlying bedrock. A subdrain was constructed along the back of ' the key. The surficial deposits in the key and adjacent pad area were removed and ' stockpiled for later placement. ' 3 A subdrain along he eastern onion of the building ad wa g p g p s constructed as ' recommended in the preliminary geotechnical investigation, referenced report No. t 1. The subdrain consists of a 4.0 inch diameter perforated pipe, embedded in gravel and wrapped in filter fabric. The subdrain is located approximately 5.0 lateral feet from the footprint of the structure along the cut /fill contact. 4) Oversized rock (greater than 12 inches) were generally removed from stockpiled ' on -site deposits. Fill consisting of a mixture of excavated materials, rock and ' clayey soils, was placed in lifts of about 8.0 inches thick. The fill was moistened as required, to achieve above optimum moisture content, and compacted by track rolling with heavy earth - moving equipment. On -site materials contain a ' considerable amount of rock fragments (approximately 20 -40 percent). ' 5) Fill slopes were generally overbuilt and trimmed back to a maximum g radient of ' 2:1 (horizontal to vertical) and track rolled. Cut slopes were excavated at a ' gradient of 2:1 (horizontal to vertical). The maximum depth of fill is approximately 12.0 feet in the southern portion of the building pad. ' March 24, 1998 W.O. G- 271107 ' Page 6 t 6) Due to "hard rock" encountered, blasting was necessary along portions of the rear cut slope and the undercut portion of the building pad. A D -8 dozer was utilized ' to rip the metavolcanic rock in the building pad and portions of the cut slope. ' The cut portion of the building pad was undercut approximately 3.0 feet and replaced with compacted fill. The undercut, in general, extends a minimum of 5.0 ' feet beyond the building footprint. The upper .0 feet of th y $ P pp 3 e building pad consists ' of granular imported fill deposits. 7) Based on selective testing, the fill was placed to a minimum of 90 percent of the ' laboratory maximum dry density, as suggested by our test results. However, ' testing of on -site deposits was significantly impeded due to numerous rock fragments. Based on our experience, on -site materials were compacted above ' optimum moisture in order to fill voids around rock fragments with finer - grained ' materials. Observation and moisture testing of these materials suggest these deposits were adequately placed and compacted. ' CONCLUSIONS AND RECOMMENDATIONS General ' Soil parameters provided in the preliminary geotechnical report for foundation and slab ' design remain valid and should be implemented during the construction phase. ' March 24, 1998 W.O. G- 271107 ' Page 7 ' Foundations Footings for the proposed residence and attached garage as designed should be founded ' a minimum of 24 inches below the lower most adjacent grade at the time of foundation excavation. A 12 inch by 12 inch grade beam should be placed across the garage opening. The base of footings should be maintained a minimum horizontal distance of ' 10 feet from the face of the nearest slope. Footings p g should be reinforced with a ' minimum of four No. 5 bars, two placed along the top of the footing and two placed near ' the base as depicted on the foundation plans and recommended in referenced report No. 1. Footings founded as recommended may be designed for a bearing value of 1500 pounds ' per square foot. The foundation design parameters assume importation of granular deposits for footing support. The bearing value indicated above is for the total dead and frequently applied live loads. This value may be increased by 33 percent for short durations of loading, including the effects of wind and seismic forces. ' Resistance to lateral load may be provided by friction acting at the base of foundations ' and by passive earth pressure. A coefficient of friction of 0.35 may be used with dead - load forces. A passive earth pressure of 250 pounds per square foot, per foot of depth ' of ranular fill penetrated to a maximum of 1500 pounds per square foot g p p p qu e t may be used. 1 ' March 24, 1998 W.O. G- 271107 ' Page 8 ' A pneumatic hammer may be required for retaining wall footings excavated into competent metavolcanic rock. The footing excavations should be reviewed by the ' geotechnical engineer prior to placement of forms. Slabs on Grade (Exterior ' Slabs on rade should be a minimum of 4.0 inches thick and reinforced g e in both ' directions with No. 3 bars placed 16 inches on center. Slabs should be underlain by a ' minimum 6.0 -inch sand blanket. Slabs including pool decking should be reinforced as indicated above and provided with saw cuts /expansion joints as recommended by the ' project structural engineer. All slabs should be cast over dense compacted non - expansive ' subgrades. Additional recommendations will be necessary if expansive soils are used under the slab. t Retaining Walls Cantilever walls (yielding) retaining a 2:1 cut slope may be designed for an active- ' equivalent fluid pressure of 4.3 pounds per cubic foot. It is suggested that the wall be ' designed with a minimum of 12 inches of freeboard and a V -type interceptor drain to collect slope drainage and possible minor debris during periods of prolonged rainfall. ' Wall footings should be designed in accordance with the foundation design g ' recommendations. All retaining walls should be provided with an adequate backdrainage ' system. The soil parameters assume a granular backfill compacted to a minimum of 90 percent of the laboratory maximum dry density. ' March 24, 1998 W.O. G- 271107 ' Page 9 ' Driveway Previous testing suggests that onsite deposits have an R -value of 18. It is suggested that ' due to the cut /fill transition and clayey onsite deposits, the proposed driveway be capped t by a minimum of 1.0 foot of imported granular deposits otherwise, a relatively thick Class 2 base section may be required. The driveway section should be a minimum of 3.0 i' inches asphaltic concrete over 6.0 inches of Class 2 base. However, it should be noted P , that the subbase and base sections should be compacted to a relative density p e 1 of 95 percent and the pavement section should be protected from adjacent water sources such as planted areas. ' Utility Line Backfill We recommend that all utilities be bedded in clean sand to at least one foot above the ' top of the conduit. The bedding should be flooded in place to fill all the voids around ' the conduit. Imported granular material compacted to at least 90 percent relative compaction may be utilized for backfill above the bedding. Care should be exercised such that backfilled utility lines do not become conduits for the migration of subsurface ' water. ' Drainage ' Specific drainage patterns should be designed by the project civil engineer. However, in ' general, pad water should be directed away from foundations and around the structure 1 March 24, 1998 W.O. G- 271107 ' Page 10 to a suitable discharge location designed by the engineer. Roof water should be collected and conducted to area drains, via non - erodible devices. Pad water should not be allowed ' to pond or flow onto slopes in an uncontrolled manner. A minimum 1.0' high ' compacted berm should be provided along the top of all fill slopes. Due to the pervious nature of granular deposits, vegetation adjacent to foundations should be avoided. If ' vegetation in these areas is desired sealed planter boxes or drought resistant plants g P g P I ' should be considered. Other alternatives may be available, however, the intent is to reduce moisture from migrating into foundation subsoils. Fill slopes should be planted with drought resistant vegetation. Irrigation should be limited to that amount necessary ' to sustain plant life. Observations and Density Testing ' Structural footing excavations should be observed by a representative of this firm, prior ' to the placement of steel. Additional fill should be placed while a representative of this firm is present to observe and test. Plan Review This report should be reviewed by the project architect and engineer in order to ' incorporate any additional recommendations into the design plans. Recommendations ' provided in the referenced report which are not superseded by this report remain applicable and should be implemented in the design and construction phases. ' March 24, 1998 W.O. G- 271107 ' Page 11 LIMITATIONS This office assumes no responsibility for any alterations made without our knowledge and ' written approval to the slopes or pad grade on the subject lot, subsequent to the issuance ' of this report. All ramps made though slopes and pads, and other areas of disturbance which require the placement of compacted fill to restore them to the original condition, ' will not be reviewed unless such backfillin operations a g p re performed under our ' observation and tested for required compaction. Observations and density testing were t performed on a minimal periodic basis only. Complete observation and testing during the grading phase was not desired by the owner. No warranty, expressed or implied, is ' given or intended with respect to the services which we have performed. The future performance of the structure is dependent upon numerous unpredictable factors such as on -site and off -site drainage, the maintenance of drainage facilities and irrigation. ' ENCLOSURES: TABLE I ' GRADING PLAN (REAR POCKET) ' March 24, 1998 W.O. G- 271107 ' Page 12 1 REFERENCES 1) PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Single- Family Residence Lot 1, APN 264 - 451 -18, Lone Hill Estates Court Olivenhain, California Prepared by Coast Geotechnical Dated October 29, 1997 ' 2) FOUNDATION PLAN REVIEW Proposed Single- Family Residence Parcel 2, TPM 95 -249, Lone Hill Estates Olivenhain, California Prepared by Coast Geotechnical ' Dated January 13, 1998 3) RESPONSE TO JOHN POWELL AND ASSOCIATES /GRADING PLAN REVIEW ' Proposed Single- Family Residence Parcel 2, TPM 95 -249, Lone Hill Estates Olivenhain, California ' Prepared by Coast Geotechnical Dated December 23, 1997 i 1 1 1 1 1 1 1 1 1 � ENCLOSURES i i i i i i i TABLE I Field Dry Density and Moisture Content ' Moisture Dry Relative Test Test Approx. Content Density % Soil ' Date No. Location Elev. $ cf Compaction Type 1/30/98 1 See Map 456.0' 18.9 110.2 94 A ' 1/30/98 2 See Map 458.0' 20.0 116.2 99 A 2/02/98 3 See Map 461.0' 19.6 110.2 94 A ' 2/05/98 4 See Map 464.0' 18.1 109.2 93 A ' 2/05/98 5 See Map 466.0' 14.8 119.2 95 B 2/05/98 6 See Map 468.0' 15.6 116.9 93 B ' 3/16/98 7 See Map 471.5' 13.6 115.0 92 C 3/16/98 8 See Map 471.0' 10.2 116.8 93 C ' 3/16/98 9 See Map 471.5' 11.1 115.7 93 C 3/16/98 10 See Map 472.5' 11.0 115.7 93 C I G- 271107 I t