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2005-9580 G
City ONGINEERING SER VICES DEPARTMENT Encinitas Capital Improvement Projects District Support Services Field Operations Sand Rep lenishment/Stormwater Compliance Subdivision Engineering Traffic Engineering February 5, 2008 Attn: lsr Pacific Bank of California 7728 Regents Road Suite 503 San Diego, CA 92122 RE: LaJoyce L. and Charles Robinson Trust Dove Hollow Lane APN 264-232-27 Grading Permit 9580-GI Final release of security Permit 9580-GI authorized earthwork, storm drainage, site retaining wall, and erosion control, all as necessary to build the described project. The Field Inspector has approved the grading and finaled the project. Therefore, a full release in the remaining security deposited is merited. Letter of Credit 1410, (in the original amount of$173,455.15), reduced by 75% to $43,363.79, is hereby released in entirety. The document original is enclosed. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincerely, , /Debra Geisha Engineering Technician anager Subdivision Engineering Financial Services Cc: Jay Lembach,Finance Manager Robinson,Charles and LaJoyce Debra Geishart File Enc. TEL 760-633-2600 / FAX 760-633-2627 505 S. Vulcan Avenue, Encinitas, California 92024-3633 TDD 760-633-2700 14 recycled paper city 0 NGINEERING SERVICES DEPARTMENT -- Encinitas Capital Improvement Projects District Support Services Field Operations Sand Replenishment/Stormwater Compliance Subdivision Engineering Traffic Engineering July 25, 2006 Attn: 1 s'Pacific Bank of California 7728 Regents Road Suite 503 San Diego, CA 92122 RE: LaJoyce L. and Charles Robinson Trust Dove Hollow Lane APN 264-232-27 Grading Permit 9580-GI Partial release of security Permit 9580-GI authorized earthwork, storm drainage, site retaining wall, and erosion control, all as necessary to build the described project. Therefore, a reduction of the security deposited is merited. Letter of Credit 1410, in the amount of$173,455.15, may be reduced by 75% to $43,363.79. The retention and a separate assignment guarantee completion of finish grading. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincere y, Debra Geish ay Lembach Engineering Technician Finance Manager Subdivision Engineering Financial Services Cc: Jay Lembach,Finance Manager Robinson, Charles and LaJoyce Debra Geishart File "PEE 760-633-2600 / FAX 760-633-2627 505 S. Vulcan Avenue, Encinitas, California 92024-3633 TDD 760-633-2700 recycled paper WESTERN PACIFIC HOMES , INC . REPORT OF SOIL INVESTIGATION ROBINSON RESIDENCE PROJECT 000 DOVE HOLLOW LANE ENCINITAS, CA 92024 PREPARED FOR: MR. AND MRS. ROBINSON 12076 OLD POWAY ROAD POWAY, CA 92064 s MAY 2 6 ` PREPARED BY: ENGINEERING SERVICES CITY Of ENCINITAS SAMSON J. ENGEDA 15008 ESPOLA ROAD POWAY, CA 92064 1555 Bella Vista Drive Encinitas, CA 92024 Phone (760) 634— 1401 Fax (760) 634 - 1402 1 November 15, 2005 Western Pacific Homes Project No. : WPH-SR1 1555 Bella Vista Drive Encinitas, CA 92024 Subject: Geotechnical Investigation APN: 264-232-27 The accompanying report includes the results of field investigation, laboratory test results and engineering analysis. The soil, foundation, and geologic conditions are discussed and information regarding the geotechnical engineering aspects of the future development is included. Samson J. Engeda, PE #52241 2 Western Pacific Homes, Samson J. Engeda,P.E. Soil Investigation INTRODUCTION This report presents the findings and conclusions of a soil investigation conducted at the site of a proposed 1-Lot residential subdivision, located at 3451 Dove Hollow Lane, in the City of Encinitas, State of California, APN: 264-232-27. The location of the property is shown on Figure No.1, entitled, "Site Location Map". DESCRIPTION OF PROJECT The project site consists of approximately 3.5 Acres and is located to the south of Dove Hollow Road. The general topography of the site slopes south-westerly, from the highest point at the north-eastern corner, elevation 368 to the lowest point at the south-western corner, elevation 316. The proposed development at this site consists of a new split level, single family dwelling house approximately 5,500 square feet of habitable space. The plans are currently in the final stages of design. The house will be of a conventional light frame wood construction. SCOPE OF WORK The objectives of this investigation are to inspect and determine the subsurface soil conditions and certain physical, engineering properties of the soils beneath the sites and to evaluate any potential adverse geotechnical conditions that could affect its construction safely and economically. To achieve the above objectives, two exploratory pits were excavated. Laboratory tests were performed on representative samples of the onsite soils to evaluate their pertinent engineering properties. The tests included expansion index, maximum density and a classification test along with a trench log sheet. FIELD INVESTIGATION To achieve the above objectives, two exploratory pits were excavated. The pits were excavated to refusal to a depth of 4.5' below the existing grade. The test pits were logged and soil samples were retrieved from the test pits for lab testing. The approximate 3 locations of the exploratory test pits are indicated on Figure 2. Logs of the exploratory test pits are presented in Appendix B, Tables 1 and 2. The soils were visually and texturally classified by the field identification procedures set forth on the Unified Soil Classification Chart. In-situ density tests and representative samples were obtained at various depths in the exploratory trenches. LABORATORY TESTS The samples collected during the field investigation were subjected to various tests in the lab to evaluate their engineering characteristics. The tests included expansion index, apparent cohesion and angle of internal friction, sulfate content,maximum density and a classification test along with a trench log sheet. The tests were performed in accordance with current ASTM testing standards or other regulatory testing procedures. A summary of the test results are presented in Appendix B of this report. GENERAL GEOLOGY AND SUBSURFACE SOIL CONDITIONS The subject site is underlain by about a 6"layer of sandy silt topsoil underlain with about 2' thick brown clayey sand and dry loose gravel layer. This clayey sand layer is underlain with 2' of Santiago peak metavolcanics, fractured and weathered rock with traces of tan sand layer to a depth of about 5'. At 5' non-weathered refusal rock was encountered. FAULTING AND SEISMICITY Review of geologic maps and literature pertaining to the general site indicate that there are no known major or active faults on or in the immediate vicinity of the site. Evidence for active faulting on the site was not observed during our investigation. There are also a number of faults in the general Southern California area, which are active and would have an effect on the site in the form of ground shaking, in case of an earthquake occurrence. These include: the San Andreas Fault, the San Jacinto Fault, the Elsinore Fault,the Coronado Fault Bank Zone, Florida Canyon Fault, Old Town Fault and the Rose Canyon Fault. The nearest known fault is the Rose Canyon Fault (nearest source Type A), which is 6.2 miles from the subject site. Other larger faults in the vicinity of this project site are the Elsinore-Julian Fault Zone (nearest source Type A), 25 miles away and the Coronado Bank Fault located approximately 21 miles south of the site. SEISMIC ANALYSIS The seismicity of the site was evaluated utilizing deterministic methods for active Quaternary faults within the general region. According to the Fault-Rupture Hazard 4 Zones Act, Quaternary faults have been classified as "active"faults, which show apparent surface rupture during the last 11,000 years (i.e. Holocene time). Deterministic Analysis—Deterministic seismicity was evaluated with Eqfault computer program (Blake), which utilizes a digitized map of known active earthquake faults and a catalogue of the Maximum Probable and Credible Earthquakes for each fault. The deterministic analysis was performed for all active faults within a specified radius of 50- miles from the site. The data generated is included in Appendix B. Based on the deterministic analysis described, 9 faults were located. The site is subject to a Maximum Probable Earthquake of 6.9 Magnitude along the Rose Canyon Fault (approximately 6.2 miles from the site), with a corresponding Peak Ground Acceleration of 0.374g. The Maximum Probable Earthquake is defined as the maximum earthquake that is considered likely to occur during a 100-year time interval. The Maximum Probable Earthquake is commonly adopted as the design earthquake for residential construction. Effective Ground Acceleration—The effective ground acceleration is associated with that part of significant ground motion, which contains repetitive strong-energy shaking that result in structural deformation. The effective ground acceleration is referred to as the Repeatable High Ground Acceleration (RHGA), and is approximately equal to 65% of the Peak Ground Acceleration for earthquakes occurring within 20 miles of a site. Based on the analysis, the site is subject to a probable RHGA of about 0.243g. Liquefaction—In consideration of the lack of a permanent water table near the ground surface, soil liquefaction does not present a significant geotechnical hazard to the proposed site development. Landslides— Subject property is not underlain by any known active fault traces. Due to the generally active seismicity of San Diego county the possibility of a landslide cannot be ruled out though remote. FINDINGS CONCLUSIONS AND RECOMMENDATIONS General Based on the results of the geotechnical investigation, it is our position that the proposed development of the site is feasible from a geotechnical standpoint. Construction Alternatives Significant amount of grading with fill heights as high as 13' is anticipated to create the building pad for this project. The type of imported fill to do this grading shall be selected fill material per the grading material specifications in Appendix A of this report. 5 The site preparation should also begin with the removal of existing vegetation and deleterious matter from the areas of the site that would support new improvements. Removal depths are generally expected to be 3 to 4 feet below existing grade. The weathered metavolcanic rock material may be mixed with the lens of sandy layer and a fine binder to use as a fill material. The most feasible type of foundation for this site would be a post-tensioned slab-on-grade foundation. Other foundation options shall be evaluated by the soils engineer if for any remote possibility a post-tensioned slab on grade may not be utilized. The post-tensioned slab on grade system shall have a minimum slab thickness of 6". Soil Design Criteria Conventional Foundations: Allowable Bearing capacity for continuous footings Founded on compacted select soils........ Minimum foundation embedment... """"""""""" 1800 inc Minimum width of footings......... ..................................................... 4 inches Coefficient of friction, sliding......... """""' 0. inches Passive earth resistance on the side of footing............................ "' 0 35 ••••........350psf/ft Post Tension (P/T)Design Parameters The slab shall have a minimum thickness of 6 inches and be designed by a Post Tension Design engineer with post tension slab on grade design. The following soil bearing capacities, footing depths and concrete mix design parameters should be incorporated into the post tension design and construction: Silt Cla Ex ansion Index 58 Edge Moisture Variation, em Center Lift, feet 5.5 Ed e Lift, feet 2.5 Differential Swell, ym Center Lift, inches 5.5 Edge Lift, inches 1.2 Allowable bearing capacity............... ........ Minimum Footing Depth of Embedment.. 1800pnc Minimum slab-on-grade thickness.. """"""""" •30 inches P/T Concrete Compressive Strength, Minimum..... .40 i inches Water-Cement ratio, m •• '''•••••••••••••••4000psi @ 28 days maximum ..0.5 Minimum Fly Ash Content......... '....."''"" Retaining Walls For retaining walls, the bearing capacity and foundation dimensions provided for the above foundations may be followed. Additional design parameters for lateral loading and resistance are as follows: 6 Active Earth Pressure for level backfill (non restrained walls)............... 40 psf At rest Earth Pressure for level backfill (restrained walls).....................60psf/ft Passive Resistance in compacted fill................. ..............250 psf/ft Earthquake Design Parameters Earthquake resistant design parameters may be determined from the UBC (1997 edition), Chapter 16. Based on the proceeding analysis and characterization of the site, the following design parameters may be adopted: Seismic Zone - 4.......... Soil Types............................................................................. Z =0.4 Seismic Source Type......................................................................Sc Seismic Coefficient, Ca...................................................................B Seismic Coefficient, Cv........... """""""""" 0.40Na Near Source Factor,Na........... ........................................................0.56Nv Near Source Factor,Nv...................................................................1.0 ............................................... .1.2 Concrete All foundation concrete shall have a minimum 28-day compressive strength of 2500psi. Concrete slabs-on-grade should be underlain by a minimum of four-inch blanket of clean, poorly graded, coarse sand or crushed rock. This blanket should consist of 100% material passing the two inch screen and no more than ten percent and five percent sieves #100 and#200, respectively. A 10 mil visqueen moisture barrier shall be placed above this layer. Proper curing techniques and a reduction in mixing water will help reduce cracking and concrete permeability. Limitations and Uniformity of Conditions The findings in this report have been derived in accordance with current standards of practice, and no warranty is expressed or implied. This report is presented with the understanding that all recommendations shall be carried out in the field by the project's superintendent. The findings in this report are applicable as of the present date. However, changes in the condition of the property can occur with the passage of time, whether the changes are due to natural processes or man made changes. 7 APPENDIX A s RECOMMENDED GRADING SPECIFICATIONS GENERAL The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the accepted plans. The recommendations contained in the accompanying report and/or the attached special provisions are a part of the Recommended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with geotechnical report for which they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written communication signed by the Engineer. OBSERVATION AND TESTING The Engineer or his authorized representative for this project shall observe and test the earthwork in accordance with these specifications. It will be necessary that the Engineer or his authorized representative provide adequate observation so that he may provide his opinion as to whether or not the work was accomplished as specified. It shall be the responsibility of the contractor to assist the Engineer and to keep him apprised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations. The Engineer shall be contacted for further recommendations. If, in the opinion of the Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc.; construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this work. Tests used to determine the degree of compaction should be performed in accordance with the following American Society for Testing and Materials test methods: Maximum Density& Moisture Content—ASTM D 1557 Density of Soil In-Place—ASTM D 1556 or ASTM D 2922 All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM testing procedures. 9 PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed and legally disposed of All areas disturbed by site grading should be left in a neat and finished appearance free from unsightly debris. After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6", brought to the proper moisture content, compacted and tested for the specified minimum degree of compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground. When the slope of the natural ground receiving fill exceeds 20 percent, the original ground shall be stepped or benched. Benches shall be cut to firm competent formational soils. The lower bench shall be at least 10 feet wide or 1 %Z times the equipment width, whichever is greater, and shall be sloped back into the hillside at a gradient of not less than two percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10-feet of the structure and properly capped off. The resulting depressions from the above described procedure should be backfilled with acceptable soil that is compacted to the requirements of the Engineer. This includes, but is not limited to, septic tanks, fuel tanks, sewer or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Engineer so that he may determine if any special recommendation will be necessary. All water wells, which will be abandoned, should be backfilled and capped in accordance to the requirements set forth by the Engineer. The top of the cap should be at least 4 feet below finish grade or 3 feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the well and should be determined by the Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Engineer. Any import material shall be approved by the Engineer before being brought to the site. 10 PLACING AND COMPCATION OF FILL Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in compacted thickness. Each layer shall have uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to economically compact the layer. Compaction equipment should either be specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rock, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minimum degree of compaction recommended in the Special provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non-structural fills is discussed in the geotechnical report, when applicable. Field observation and compaction tests to estimate the degree of compaction of the fill shall be taken by the Engineer or his representative. The location and frequency of the tests shall be at the sole discretion of the Engineer. When the compaction test indicates that a particular layer is at less than the required degree of compaction, the layer shall be reworked to the satisfaction of the Engineer and until the desired relative compaction has been obtained. Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by sheepsfoot roller shall be at vertical intervals of not greater than 4 feet. In addition, fill slopes at a ratio of two horizontal to one vertical or flatter, should be track-rolled. Steeper fill slopes shall be over-built and cutback to finish contours after the slope has been constructed. Slope compaction operations shall result in all fill material 6 or more inches inward from the finished face of the slope having a relative compaction of at least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions section of this specification. The compaction operation on the slopes shall be continued until the Engineer is of the opinion that the slopes will be sufficiently stable. Density tests in the slopes will be made by the Engineer during construction of the slopes to determine if the required compaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Engineer or his representative in the form of a daily field report. If the method of achieving the required slope compaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction is obtained, at no cost to the Owner or Engineer. 11 CUT SLOPES The Engineer or his representative shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding,joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineer or an Engineering Geologist to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than the allowed by the ordinances of the controlling governmental agency. ENGINEERING OBSERVATION Field observation by the Engineer or his representative shall be made during the filling and compaction operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Engineer or his representative or the observation and testing release the Grading Contractor from his duty to compact all fill material to the specified degree of compaction. SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before acceptance of work. 12 RECOMMENDED GRADING SPECIFICATIONS—SPECIAL PROVISIONS RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural ground, compacted fill and compacted backfill shall be at least 90 percent. For street and parking lot sub-grade, the upper six inches should be compacted to at least 95%relative compaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29-C. OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil over 6 inches in diameter. Oversized materials should not be placed in fill unless recommendations of placement of such material are provided by the Engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and re-compacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required. 13 APPENDIX B 14 LABORATORY TEST RESULTS RESULTS OF EXPANSION INDEX TEST An expansion test in conformance with ASTM D4829 was performed on a representative sample of the colluvium to determine volumetric change characteristics with change in moisture content. The recorded expansion of the sample is presented as follows: INITIAL SATURATED INITIAL DRY MOISTURE MOISTURE DENSITY EXPANSION CONTENT% CONTENT% LOCATION ATION LB./CU. FT. INDEX 18.1 37.3 87.0 T-2 @ 1.0' 58 RESULTS OF PARTICLE SIZE ANALYSIS 3' 2" - 1" - 1/2" - 3/8" - #4 - #8 100 #16 94 #30 81 #40 63 #60 52 #100 37 #200 29 24 USCS SC RESULTS OF ATTERBERG LIMITS 26.4 CL DENSITY FROM SUBMERGED WAX SAMPLES 7 T T-1 2.0' (Js 3.8 T-2 1.0' Qa] 151.4 16.4 97.5 T-2 4.0' (Js ) 4.2 163.0 15 FIGURE No. 1 [3200-3319] Dove Hollow Rd Encinitas CA 92024 US Notes: The Robinson's Residence Soils Report Site Location Map �' T ' F _ V V pp - �� •Haan $ T kapwft tif ,k x �n .�F x • win 31, � �� �� �'�i114�xW'Mi7l1�*ka E .E' d"" ��� � 63P?•'.. �i4..-Mi �9�R�C�M — — — — — — — — • ............ r O w OQHf?W y N G2.9+4 2 �v A E v,L 2 �r n �' \ \ ..S ��\\\ `\`362:9 loo Q>>vv v FG v w o ; \ 'FG w° 362.6`v 3q9 \\ .... Xv CL 3 ` �a +r O LO ti �n RESIDENCE 0 STIGATION OCATIONS NORTH No. 2 SCALE: 1" = 40'-0" Table 1 ROBINSON'S RESIDENCE LOG OF TEST TRENCH NUMBER T-1 Date Excavated: 11/10/05 Logged By: MD Equipment: Backhoe Engineer: SE Surface Elevation (ft): 360 Depth to Water: NO WATER DETECTED � U C/) a LU SUMMARY OF SUBSURFACE CONDITIONS a O Q L ~ 1A O j Q: 0 1 MH 6"To soil CK SP Brown Clayey Sand w/Gravel 20 11 Santiago Peak Metavoicanics, Fractured Rock, CK 1 115 5 2 SM Weathered Lens of Sand CK 6 6 135 3 4 5 Refusal Bedrock-Sedimenta CK Trench Ended at 5 feet 2 145 Table 2 ROBINSON'S RESIDENCE LOG OF TEST TRENCH NUMBER T-1 Date Excavated: 11/10/05 Logged By: MD Equipment: Backhoe (ft): 360 Engineer: SE Surface Elevation Depth to Water: NO WATER DETECTED LL LL U f!j co o d LU a j W IONS SUMMARY OF SUBSURFACE CONDITIONS a Lu cc Fes-co O D MH 6"To soil SP BrownCla a Sand w/Gravel CK 20 110 Santia o Peak Metavolcanics, Fractured Rock, CK 12 115 2 SM Weathered Lens of Sand CK 6 135 3 4 Refusal Bedrock-Sedimenta Trench Ended at 4 feet CK 2 145 EQSEARCH Version 3.00 MAGNITUDE RANGE: MINIMUM MAGNITUDE: 4.00 MAXIMUM MAGNITUDE: 9.00 SITE COORDINATES: SITE LATITUDE: 33.0696 SITE LONGITUDE: 117.2111 SEARCH RADIUS:50 mi ATTENUATION RELATION:8)Bozorgnia Campbell Niazi(1999)Hor.-Holocene SolWncor UNCERTAINTY(M=Median,S=Sigma):M Number of Sigmas: 0.0 DISTANCE MEASURE: cdist SCOND: 0 Basement Depth: 5.00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: CDMGFLTE.DAT MINIMUM DEPTH VALUE(km): 3.0 EQFAULT SUMMARY DETERMINISTIC SITE PARAMETERS I ►ESTIMATED MAX.EARTHQUAKE EVENT ABBREVIATED APPROXIMATE I FAULT NAME I DISTANCE I MAXIMUM I PEAK JEST.SITE 1 mi (km) IEARTHQUAKEJ SITE [INTENSITY MAG.(Mw)I ACCEL.g JMOD.MERC. ROSE CANYON 1 6.2( 9.9)1 6.9 1 0.374 1 IX NEWPORT-INGLEWOOD(Offshore) 1 13.5( 21.8)1 8.9 1 0.210 J Vill CORONADO BANK 1 20.7( 33.3)1 7.4 1 0.188 1 VIII ELSINORE-JULIAN 1 25.5( 41.1)1 7.1 1 0.121 1 VII ELSINORE-TEMECULA J 25.8( 41.5)1 6.8 1 0.096 1 VII EARTHQUAKE VALLEY 1 38.8( 62.4)1 6.5 1 0.046 1 VI ELSINORE-GLEN IVY 1 41.3( 66.5)1 8.8 1 0.053 1 Vl PALDS VERDES 1 43.9( 70.7)1 7.1 1 0.063 1 VI SAN JACINTO-ANZA 1 48.3( 77.7)1 7.2 1 0.o60 I VI -END OF SEARCH- 9 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE ROSE CANYON FAULT IS CLOSEST TO THE SITE. IT IS ABOUT 6.2 MILES(9.9 km)AWAY. LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION:0.3743 g THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 7.0 MILES(11.3 km)AWAY. LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS:6.8 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH:0.347 g COEFFICIENTS FOR GUTENBERG&RICHTER RECURRENCE RELATION: a-value= 3.109 b-value= 0.830 beta-value= 1.912 TABLE OF MAGNITUDES AND EXCEEDANCES: Earthquake I Number of Times I Cumulative Magnitude J Exceeded I No./Year 4.0 J 132 I 0.65672 5.0 I 4.5 44 1 0.21891 1 19 J 0.09453 5.5 1 6 i 0.02985 6.0 J 3 1 0.01493 6.5 J 2 1 0.00995 EARTHQUAKE EPICENTER MAP 1100 1000 900 i 800 700 600 500 l 400 300 3 200 LEGEND X M=4 100 J M=5 M=6 ` M=7 e Z3 0 0 M_8 �J -100 -400 -300 -200 -100 0 100 200 300 400 500 600 HYDROLOGY/HYDRAULIC ANALYSIS FOR ROBINSON RESIDENCE 000 DOVE HOLLOW LANE APN 264-232-27 Prepared By: Samson J. Engeda P� 15008 Espola Road N0. 52 41 � Exp. Poway, CA 92064 cP CIVIL OF CALiFOQ y HYDROLOGY/HYDRAULIC ANALYSIS FOR ROBINSON RESIDENCE 000 DOVE HOLLOW LANE APN 264-232-27 INTRODUCTION The proposed development at this site consists of a new split level, single family dwelling of approximately 5,500 square feet of habitable space. The house will be of a conventional light frame wood construction. The project site consists of approximately 3.5 Acres and is located to the south of Dove Hollow Road. The general topography of the site slopes south-westerly, from the highest point at the north-eastern corner, elevation 368 to the lowest point at the south-western corner, elevation 316. 10-Year Storm Analysis Method: The Rational Method A =3.5 Acres = 152,629 ft2 i) Determination of Runoff Coefficients, Urban Values Roof—0.9 Concrete—0.95 Asphalt—0.85 Planted Area/Lawn—0.5 (Compacted)/0.3 (Non-compacted) a) Predevelopment Values, Rolling Pasture—0.26 Asphalt=6,096 ft2 Rolling Pasture= 146,533 ft2 Determine Weighted Runoff Coefficient based on tributary areas for the v for the pre-development condition of the site, various surfaces, Cavg = (Cl*Al + .-..+Cn*An)/(EA.,) = 0.28 b) Post Development Values, Asphalt= 6,096 ft2 (0.14 AC) Roof= 8,044 ft2 (0.185 AC) Concrete=5,603 ft2 (0.129 AC) Planted Area=24,138 ft2 (0.55 AC) Rolling Pasture= 108,748 ft2 (2.49 AC) Determine Weighted Runoff Coefficient based on tributary areas for the various for the post-development condition of the site, surfaces, Cavg=(C1*A1 + ....+Cn*An)/(EAn) =0.38 ii) Determination of Time of Concentration, Tc Tc = Ti + Tt From Table 3-2, of the San Diego County Hydrology Manual, For a Low Density Residential (LDR) below 1 Dwelling Unit (DU)per Acre and an 8% slope, • Ti = 7.1 minutes From Figure3-4, Nomograph for Determination of Tc, determine Tt, for a DE = 368-316= 52' and L= 650', • Tt =3.2 minutes Tc =Ti + Tt= 7.1 min+ 3.2min= 10.3 min iii) Determination of Rainfall Intensity, I From the Isopluvial Chart of Appendix B, the 6-hours duration and the 24-hours duration charts yield, inches of Precipitation of P-6hrs = 1.9 inches and P-24hrs=3 inches, with a P-6hrs to a P-24hrs ratio= 63.33%<65%, OK. P-adj =P-6hrs = 1.9 inches Therefore, from Figure 3-1 using Tc = 10.3min and a 6-hr precipitation of 1.9 inches, I= 3.2 inches/hour. Q = C*I*A Volume of Dischar e—Pre-develo went Condition Q =0.28 * 3.2in/hr * 3.5Ac=3.136 cfs Volume of Dischar Ye—Post-develo went Condition Q= 0.38 * 3.2in/hr * 3.5Ac =4.256 cfs Volume of Runoff—Net Increase Q-net=(Q-post)—(Q-pre) Q-net=4.256 cfs—3.136 cfs= 1.12 cfs V-net= Q-net * Tc = (1.12 cfs) * (10.3min) * (60sec/min) =692.2 ft3 For an infiltration basin with a cross-sectional dimension of 5-feet wide by 18" deep, A = 5' * 1.5' = 7.5ft2 Length of Run; L-run= 692.2 ft3/7.5 ft2 = 93 ft say 100 ft long infiltration basin suffice. i • • • R • • s�'R•��—SAS"' "..�.••.��•---�-'_'Mmam a ROM sa®:-� ia:i:mia�9s% 00 ii �a •�� MEN ! .:. s • , r■rrirr■■vi►�rir�r.�►.�r����i�r�riu�ia���� om ou MUM =. -'=. saw::: .55•�� " ii�i�" ��`�L�" .i—ir�"i�i����• r:' "' maxiii�a'i�a�i r,�'�'i'�i�"a�r®® i•����,��_w�/n��wq��•r��►iAga l�Hq��i�,��`Ir.Ht1�I�a.�.���Hriw.�•�I/.w��!���•.��/��iNq�tNl��p� -- mass WAN Mill NWM IMMMUMMIUMME JLVAIFAIN tits M=W.-A !� =MEMBER lta t�ti�� tNE1lA m/ ��WAWM'//MW/�.Rti �� �tNttttttttip �i�i mm full F, 9, V 9, ,r.Nrr r�,r►���r r��■■�iiiiii i� � i�RUN of OFM AE Tc EQUATION Feet 11.9L3 .385 _QE '1 0 5400 Tc = Time of concentration(hours) Watercourse Distance(miles) 44G© AE = Change in elevation along 3000 effective slope line(See Figure 3-5)(feet) Tc. Hours Minutes 2000 4 240 3 184 1000 900 800 2 V0 120 600♦ 100 500\ 90 ♦ 400 \ 80 \t�+� 70 300 �iP 1 60 \ so 200 \ \ L \ Mlles Feet \ 30 100 \1 4000 20 \ is 3000 16 \so 0.5 \ \ 14 40 \ 2000 \ \ 12 1800 30 \ 1640 \ 10 1400 \ \ g \ 1200 8 20 \ 1000 7 900 8w 6 700 5 10 500\\ 4 '0 300 5 �!E 340 L Tc SOURCE:California Division of Highways(1941)and Kirpich(1940) R E I Nomograph for Determination of F U L' Time of Concentration (Tc)or Travel Time(Tt)for Natural Watersheds �i San Diego County Hydrology Manual Date: June 2003 Section: 3 Page: 12 of 26 Note that the Initial Time of Concentration should be reflective of the general land-use at the upstream end of a drainage basin. A single lot with an area of two or less acres does not have a significant effect where the drainage basin area is 20 to 600 acres. Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in hydrology studies. Initial T; values based on average C values for the Land Use Element are also included. These values can be used in planning and design applications as described below. Exceptions may be approved by the "Regulating Agency" when submitted with a detailed study. Table 3-2 MAXIMUM OVERLAND FLOW LENGTH (LM) & INITIAL TIME OF CONCENTRATION Ti Element* DU/ .5% 1% 2% 3% 5% 10% Acre LM T; LM Ti LM Ti LM T; LM Ti LM Ti Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9 LDR 1 50 12.2 70 11.5 85 10.0 100 9.5 100 8.0 100 6.4 LDR 2 50 11.3 70 10.5 85 9.2 100 8.8 100 7.4 100 5.8, LDR 2.9 50 10.7 70 10.0 85 8.8 95 8.1 100 7.0 100 5.6 MDR 4.3 . 50 10.2 70 9.6 80 8.1 95 7.8 100 6.7 100 5.3 MDR 7.3 50 9.2 65 8.4 80 7.4 95 7.0 100 6.0 100 4.8 MDR 10.9 50 8.7 65 7.9 80 6.9 90 6.4 100 5.7 100 4.5 MDR 14.5 50 8.2 65 7.4 80 6.5 90 6.0 100 5.4 100 4.3 HDR 24 50 6.7 65 6.1 75 5.1 90 4.9 95 4.3 100 3.5 HDR 43 50 5.3 65 4.7 75 4.0 85 3.8 -- 3.4 100 2.7 N. Corn 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7 G. Corn 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4 O.P./Com 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2 Limited 1. 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2 General 1. 50 3.7 60 3.2 70 2.7 80 2.6 90 2.3 100 1.9 *See Table 3-1 for more detailed description 3-12 ROBINSON RESIDENCE APN 264-232-27 (3 din Cost Estimate Item No. Descri tion Total Item Unit Quanti Unit Price Price Earthwork 1 Clear and Grub SF 5000 2 Excavate&Fill 0.45 2250 CY 1637 11.5 3 I 18825.5 m ort&Fill CY 2099 4 Draina a ditch 22 46178 LF 520 15 7800 Erosion Control 5 Gravel Ba EA 6 Silt Fence 2000 1.1 2200 7 Fiber Rolls LF 2000 1.6 3200 LF 2000 2.25 4500 8 Fiber Matt SF 10000 0.4 Stabilized 4000 Construction 9 Entrance SF 600 Concrete 5.25 3150 10 Washout EA 1 11 Inlet Protection EA 4 150 150 500 Structures 600 12 Ke -Stone Wall FT 2 160 30 4800 subtotal $98,003.50 Contingency 10% $9,800.35 TOTAL $107,803.85 No. 052241 T��C/VIL ^� Nov 1 ILI