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2006-220 G PASCO LAPET SUITER .. _ '` r' & ASSOCIATES October 17. 2108 Ben Oliver Citv of Encinitas Inspector 505 S. Volcan Ave Encinitas CA, 920-14 RE: HAGGQL01M RESIDENCE 430 ANDREW AVE Chen. Pursuant to your request, we have preparCd a brut letter outlining the field modifications to grading plan no. 220-G located at 430 Andrew Ave. The modifications are as follows: -The grade around the structure shall be raised to ensure runoff from the existino upstream travel way remains in the existing flowline in the travel way and continues to flow away from the structure. -A- small raised curb shall be constructed to hold the s-,rade acliacent to the northern driveway entrance up to facilitate the above mentioned modification. Che raised curb shall not encroach into the road«a\ casement. -The 12' traffic grate shall be reduced to a length no less than 14% however the grate shall NOT to be reduced in width. These modifications have been reviewed by our office and deemed to be ill keeping with the intent of the original design. Additionaliv. these modifications have been discussed with the city enuineer at the City of Encinitas Engineering Department. V y titilysyours. r W. Join Stu er, PE President \\JSiw_js E'nclosures s � DATE PROJECT NO. FIELD REPORT PROJECT LOCATION CONTRACTOR OWNER WEATHER CONDITIONS To i. PRESENT AT SITE EQUIPMENT SUMMARY OF INSPECTION: C(L Y-'6 0 c' rote c"l LA u 4 '7 �j HETHERINGTON ENGINEERING, INC. SOIL&FOUNDATION ENGINEERING ENGINEERING GEOLOGY-HYDROGEOLOGY 5205 Avenida Encinas, Suite A Carlsbad,California 92008 (760)931-1917 SIGNATURE %2. 32242 Paseo Adelanto, Suite C San Juan Capistrano,California 92675 COPIESTO: (949)487-9060 ° C I T Y OF E N C I N I T A C ENGINEERING SERVICES DEPARTMENT _ 505 S , VULCAN AVE , ENCINITAS, CA 92024 „ GRADING PERMIT PERMIT NO. : 22 111 PARCEL NO. : 216-063--3300 PLAN NO . : JOB SITE ADDRESS : 430 ANDREW-' PVE CASE NO, APPLICANT NAME CANDY HAGGBLOM MAILING ADDRESS : 430 ANDREW AVE PHONE NO. : ?6}.i-75--=613c CITY: ENCINITAS -l-'"'ATE' C. ZIP : 92024- CONTRACTOR : LYNX ESCAVATING & CYRADING PHONE NO. LICENSE NO. : 861861 LICENSE TYPE: C-12 ENGINEER : PASCO ENGINEERING, PHONE NO. : 856-25,9-8212 PERMIT ISSUE DATE: 11/16, 06 PERMIT EXP . DATT - 6/Q? PERMIT ISSUED BY INSPECTO QUIGG --------------------------- PERMIT FEES & DEPOSITS ----------------------.------- _ 1 . PERMIT FEE . 00 2 . PLAN CHECK DEPOSIT: � 00 3 . INSPECTION FEE 565 . £1 4 . INSPECTION DEPOSIT: . 0 5 . PLAN CHECK FEE . 0c, 6 . SECURITY DEPOSIT 11 , 312 . 29 7 . FLOOD CONTROL FEE : 67 . 81 8 . TRAFFIC' FEE OQ ------------------ ------- DESCRIPTION OF WORK ------------------------------------ PERMIT TO GUARANTEE BOTH PERFORMANCE AND LABOR AND MRTERIALS FOR EARTHWORK, DRAINAGE, PRIVATE. IMPROVEMENT,— ?ND EROSION C ONTR�DL . CONTRACTOR MUST MAINTAIN TRAFFIC: CONTROL AT PLL TIMES PER W] .A. T. C" .H. STANDARDS OR CITY RPPRr-'VFD `T'R�. '�tTC ;;ONTR T. PLAN ,, LETTER DATED NOVEMBER 2006 APPLIES . -- INSPECTION ---------------- - DATE -_ ____ INSPECTOR' S SI'GNAtURE. INITIAL INSPECTION COMPACTION REPORT RECEIVED ENGINEER . CERT . RECEIVED FIOUGH GRADING INSPECTION -� FINAL INSPECTION / _a - - ---------------------------------------------------/ � _ - _ _ - I- HEREBY ACKNOWLEDGE THAT I HAVE READ THE APPLICATION AND STATE "A"T THE INFORMATION IS CORRECT AND AGREE TO COMPLY WITH ALL CITY ORDINANCES° AND STATE LAWS REGULATING EXCAVATING AND GRADING, FIND THE PROVISIONS AND CONI3ITIONS OF ANY PERMIT ISSUED PURSUANT TO THIS APPLICATION . 81GNATUF�g DATE SIGNED T ! / z" PRINT N TELEPHONE NUMBER CIRCLE ONE: 1 .rOWNEFc,)r' 2 . AGENT 3 . OTHER_ PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING Date 1/6/09 PLSA 1498 City of Encinitas Engineering Services Permits 505 South Vulcan Avenue Encinitas, CA. 92024 RE: ENGINEER'S FINAL GRADINGBMP CERTIFICATION FOR GRADING PERMIT NO.220-G The grading Plan permit number 220-G has been performed in substantial conformance with the approved grading plan or as shown on the"As Graded"plan. Final grading inspection has demonstrated that lot drainage conforms to the approved grading plan and that swales drain a minimum of 1%to the street and/or an appropriate drainage system. All the Low Impact Development, Source Control; and Treatment Control Best Management Practices as shown on the drawing and required by the Best Management Practice Manual Part II were constructed and are ope at n 1,together with the required maintenance covenant(s). Engineer of Record Date l l Y ��si�ri�d-arld'sexl"ed) f` Verification by the Engineering Inspector of this fact is done by the Inspector's signatiIIf&hereon and will take place only after the above is signed and stamped and will not relieve the Engineer of Record of the ultimate responsibility: Engineering Inspector Date The above information shall be on the Engineer of Records's letterhead and shall be signed and sealed by the Engineer of Record Very truly yours, Pasco Laret Suiter&Associates W.Justin Suiter, RCE 68964 President 535 N Coast Highway 101 Ste A Solana Beach, California 92075 j ph 858.259.8212 1 fx 858.259.4812 1 plsaengineering.com PASCO ENGINEERING, INC. 535 NORTH HIGHWAY 101, SUITE A SOLANA BEACH, CA 92075 (858)259-8212 WAYNE A. PASCO FAX(858)259-4812 R.C.E.29577 January 4, 2007 PE 1498 City of Encinitas Engineering Services Permits 505 S. Vulcan Avenue Encinitas, CA 92024 RE: ENGINEER'S PAD CERTIFICATION 430 ANDREW AVE. (220-G) To Whom It May Concern: Pursuant to Section 23.24.3 10 of the Encinitas Municipal Code, this letter is hereby submitted as a Pad Certification Letter for the above referenced site as the Surveyor for the subject property. I hereby state that the rough grading for this project has been completed in conformance with the approved plan and requirements of the City of Encinitas Codes and Standards. Certification was performed on January 4, 2007. The following is a list of pad elevations as field verified and depicted on the approved grading plan pursuant to Section 23.24.310 (B): Pad Elevation Pad Elevation Location Per Plan Per Field Measurement LOWER PAD 109.5 109.6 MIDDLE PAD 114.0 114.1 UPPER PAD 116.0 116.0 If you should have any questions in reference to the information listed above,please do not hesitate to contact this office. Very truly yours, PASCO ENGINEERING, INC. �p LAND SU N C. "�� O oseph Yul as LS 5211 ` Director of Land Surveying Exp. 06/30/07 qlF OF CALZF�� PASCO ENGINEERING5 INC. WAYNE A. PASCO R.C.E.29577 535 NORTH HIGHWAY 101, SUITE A JOSEPH YUHAS SOLANA BEACH, CA 92075 P.L.S.5211 (858) 259-8212 FAX (858) 259-4812 W.JUSTIN SUITER R.C.E.68964 November 13, 2007 PE 1498 Ruben Macabitis Engineering Department City of Encinitas 505 So. Vulcan Avenue Encinitas, CA 92024 Dear Ruben: It is the professional opinion of Pasco Engineering that based upon existing topographic information all pre-development drainage patterns have been maintained and there is no additional runoff form the property or off site that is discharged on the access driveway off of Andrew Ave. Please call if you have any questions. Regards, QROFESS/p PASCO N INEERING, INC �`� SUST/N Fy a3 C69A � M ,t EXP o7 W. Justin Suiter, Vice-President RCE 68964 srq CIVIL �P TFOFCAU*O'�" x " t vooF * 3 SITE �� g _ z F `� ss Y �, 1 TATIEIiMM Ip A� � ar « ff` �.•2 vt� Cu 4 i ``` ��—�-� —_ ro a�� BE,IO1 L _ AgI >e AN ra y Y �a7i ADAPTED FROM: The Thomas Guide,San Diego County,2004 Edition i SCALE: V-2000' `'— (1 Grid=0.5 x 0.5 miles) 0 LOCATION MAP 430 Andrew Avenue HETHERINGTON ENGINEERING, INC. Encinitas, California `�-- GEOTECHNICAL CONSULTANTS ,, � PROJECT NO. 5429.1 I FIGURE NO. 1 L-T- GEOTECHNICAL INVESTIGATION Project No. 5429.1 I Log No. 9937 1 -�- April 7, 2006 Page 2 `-I driveway on the west, and existing residential structures on the north and east. The lot � g consists of a rectangular shaped parcel that slopes gently to the north and presently f supports a two-story, wood-frame residence that appears to be supported by conventional continuous footings with either raised wood or slab-on-grade floors. The back yard contains several sheds and various fruit trees, planter beds and a small swimming pool. fLandscaping around the existing residence consists of various trees and bushes. Concrete y ' - driveways, flatwork and concrete pavers also cover relatively large p ortions of the backyard area. The front concrete driveway covers most of the front yard and west side f yard and connects Andrew Avenue with the adjacent private driveway. PROPOSED DEVELOPMENT Based upon our discussions with you and our review of a copy of the site plan provided by Chereskin Architecture, we understand that proposed site improvements consist of a two-story addition at the north and west sides of the existing residence and the construction of a garage/storage shed structure and a separate storage shed in the central portion of the lot. We anticipate that the proposed structures will be of wood-frame construction and building loads are expected to be typical for this type of relatively light construction. Site grading is expected to be minor. t SUBSURFACE EXPLORATION Subsurface conditions were explored by manually advancing three hand-auger borings to depths of approximately 4 to 8-feet below existing site grades. The approximate locations of the hand-auger borings are shown on the attached Plot Plan, Figure 2. The subsurface exploration was supervised by a geologist from this office, who visually classified the soil and formational materials, and obtained bulk and relatively undisturbed samples for laboratory testing. The soils were visually classified according to the Unified Soil Classification System. Classifications are shown on the attached Boring Logs, Figures 3 and 4. LABORATORY TESTING r Laboratory testing was performed on samples obtained during the subsurface exploration. Tests performed consisted of the following: • Dry Density/Moisture Content(ASTM: D 2216) r-A • Sulfate Content(EPA 9038) l ;� HETHERINGTON ENGINEERING, INC. J 0 ,— GEOTECHNICAL INVESTIGATION Project No. 5429.1 f Log No. 9937 L-, April 7, 2006 Page 3 I-A Expansion Index (ASTM: D 4829) I�-� • Maximum Dry Density/optimum Moisture sture Content (ASTM: D 1557) Direct Shear(ASTM: D 3080) f Results of the dry density and moisture content determinations are presented on the Boring Logs, Figures 3 and 4. The remaining laboratory test results are presented on the attached Laboratory Test Results,Figure 5. T-� SOIL AND GEOLOGIC CONDITIONS r 1. Geologic Setting The subject site lies within the marine terrace commonly known as the Palomar Terrace that is contained within the coastal plain region of northern San Diego County, California. The.coastal plain region is characterized by numerous regressive marine terraces of Pleistocene age that have been established above wave-cut platforms of underlying Eocene bedrock and were formed during glacio-eustatic changes in sea-level. The terraces extend from areas of higher elevations east of the site and descend generally west-southwest in a"stairstep" fashion down to the present day coastline. These marine terraces increase in age eastward. The Palomar Terrace is the third youngest terrace after the Bird Rock and Nestor Terraces. The site area is contained within the north central portion of the USGS Encinitas 7-1/2 minute quadrangle. The Palomar Terrace, a Pleistocene marine terrace, underlies the entire site. The Scripps Formation is exposed to the north of the site within the cliffs along the Batiquitos Lagoon and to the east and northeast within roadcut slopes. It is anticipated Al that this formation underlies the terrace deposits at depth. Structurally, bedding within the terrace deposits is considered to be essentially massive. Active fault zones within the general site region include the offshore extension of the Rose Canyon/Newport-Inglewood, Coronado Bank/Palos Verdes / Hills and the Elsinore, which are located approximately 3.4-miles southwest, 17.5- E miles southwest and 27.2-miles northeast from the site,respectively. No known or reported deep-seated landsliding is known to exist on the site. No —� known or reported active or potentially active faults exist within the site. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 IJ April 7, 2006 IJ Page 4 2. Observed Geologic Units 0 a. Fill - A relatively hin layer ayer of fill was observed to overlie the Palomar Terrace within the areas planned for construction. The maximum observed thickness of fill was approximately 4-feet at Boring HA-2. It is anticipated that the fill thickness within areas of proposed site improvements will not exceed 5-feet. In general, the fill consisted of dark brown to brown, damp to moist, loose silty to slightly clayey fine to medium sand. The fill is not considered to be suitable for support of the proposed structures and will require removal and recompaction prior to the placement of compacted fill and/or construction of settlement sensitive site improvements b. Terrace Deposits - The entire site is underlain by the Palomar Terrace, a Pleistocene-age marine terrace deposit. The upper 1.5 to 2-feet of this unit was observed to be moderately weathered and the unit consists generally of red brown, fine to medium sand with some silt that is damp to very moist and medium dense to dense. At depth this unit becomes orange red brown and dense to very dense. —� 3. Groundwater Groundwater was not encountered in the hand-auger borings. It should be noted, -� however, that fluctuations in the amount and level of groundwater might occur due to variations in rainfall,irrigation and other factors that may not have been evident at the time of our field investigation. J SEISMICITY The site is within the seismically active southern California region. There are, however, no known active faults located within or adjacent to the site. The La Costa Avenue fault is mapped approximately 700-feet east of the site, however, no evidence of offset within the last 11,000 years would indicate that this fault is not active. Active fault zones currently mapped within the general site region include the offshore extension of the Rose Canyon/Newport-Inglewood, offshore Coronado Bank/Palos Verdes Hills and the Elsinore, which are located approximately 3.4-miles (5.5-kilometers) southwest, 17.5- miles (28-kilometers) southwest and 27.2-miles (43.5-kilometers) northeast from the site, respectively. Strong ground motion could also be expected from earthquakes occurring along the offshore San Diego Trough, San Jacinto and San Andreas fault zones, which lie approximately 30-miles southwest, 48-miles northeast and 60 to 70-miles northeast of the site, respectively. The San Clemente fault, which lies approximately 50-miles southwest HETHERINGTON ENGINEERING INC. a _- _ --- - h f GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 5 of the site, as well as numerous other offshore faults could also cause se strong ground motion. The following table lists the known active faults that [ would have the most significant I impact on the site: Maximum Probable Fault Earthquake Slip Rate Fault (Moment Magnitude) (mm/year) ..Type f Rose Canyon l - (3.4-miles/5.5-kilometers SW) 7.2 1.5 B Coronado Bank/Palos Verdes Hills 17.5-miles/28-kilometers SW) 7.6 3 B Elsinore (Julian Segment) (27.2-miles/43.5-kilometers NE) 7.1 5 A SEISMIC EFFECTS 1. Ground Motions The most significant probable earthquake to affect the pro perty would be a 7.2 magnitude earthquake on the Rose Canyon/Newport-Inglewood fault. Depiction of L� probabilistic seismic hazard analysis utilizing a consensus of historical seismic data and the respective regional geologic conditions that are shown on "The Revised 2002 California Probabilistic Seismic-Hazard Maps" (Reference 3), indicates that peak ground accelerations of about 0.20 to 0.30g are possible with a 10% probability of being exceeded in 50-years. 2. Landslidina Review of the referenced geologic literature indicates that the subject property has no previously mapped ancient landslide deposits. The risk of seismically induced landsliding affecting the site is considered low due to the gently sloping topography. 3. Ground Cracks The risk of fault surface rupture due to active faulting is considered low due to the ` absence of an active fault on site. Ground cracks due to shaking from seismic events r in the region are possible, as with all of southern California. - ( HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 6 4. Liquefaction 1 The risk of seismically induced liquefaction within the site is considered low due to the lack of shallow groundwater and the relatively dense nature of the underlying terrace deposits. 5. Tsunamis The risk for seismically generated ocean waves to affect the site is considered low �( due to the elevation above sea level. t CONCLUSIONS AND RECOMMENDATIONS l 1. General The proposed building addition, backyard garage/storage shed and storage shed are considered feasible from a geotechnical standpoint. Grading and foundation plans should take into account the appropriate geotechnical features of the site. Assuming that the recommendations presented in this report and good construction practices are utilized during the design and construction, the proposed construction is not anticipated to adversely impact the adjacent properties from a geotechnical standpoint. 2. Seismic Parameters for Structural Design Seismic considerations that should be used for structural design at the site include the l: following: a. Ground Motion— The proposed structures should be designed and constructed to resist the effects of seismic ground motions as provided in Chapter 16, Division IV of the 2001 California Building Code. The basis for the design is dependent on 1 and considers seismic zoning, site characteristics, occupancy, configuration, structural system and building height. b. Soil Profile Type — In accordance with Section 1629.3.1, Table 16-J, and the underlying geologic conditions, a site Soil Profile of Type SD is considered appropriate for the subject property. c. Seismic Zone — In accordance with Section 1629.1 and Figure - gu 16 2, the subject site is situated within Seismic Zone 4. HETHERINGTON ENGINEERING, INC. ,I GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7,2006 Page 7 d. Seismic Zone Factor (z) — A Seismic Zone Factor of 0.40 is assigned based on Table 16-I. Since the site is within Seismic Zone 4, Section 1629.4.2 requires a Seismic Source Type and Near Source Factor. Ce. Near-Source Factor(Na and Nv)—Based on the known active faults in the region and distance of the faults from the site, a Seismic Source Type of B per Table 16- U, and Near Source Factors of Na= 1.0 per Table 16-S and Nv = 1.18 per Table 16-T are provided. f. Seismic Coefficients (Ca and Cv)—Using the Soil Profile Type and Seismic Zone [ Factor along with Tables 16-Q and 16-R, the Seismic Coefficients Ca= 0.44 (Na) and Cv=0.64 (Nv) are provided, or Ca=0.44 and Cv=0.76. 3. Slope Stability [ 4 The site is gently sloping to the north and no cut or fill slopes are anticipated, consequently, slope stability is not a design consideration. 4. Site Gradine L Prior to grading, the portions of the site where improvements are proposed should be cleared of existing surface obstructions, vegetation and debris. Materials generated during clearing should be disposed of at an approved location off-site. Holes resulting from the removal of buried obstructions should be backfilled with compacted fill. Old septic systems, if encountered, should be removed and backfilled in accordance with local regulations. Within the limits of the proposed structures, the existing fill soils and upper 1 to 2-feet of the terrace deposits should be removed down to F L approved terrace deposits and replaced with compacted fill in order to achieve final design finish grades. Removal depths are anticipated to extend approximately 2 to 5- feet below the existing grade. Following removals the exposed terrace deposits I-'--L should be scarified to a depth of 6 to 8-inches, moisture conditioned to about optimum moisture content and compacted to at least 90-percent relative compaction. The recommended removals and compaction should extend to at least 5-feet outside F-L the limits of proposed site improvements where practical. Actual removal depths should be determined in the field by the Geotechnical Consultant based on conditions exposed during grading. Fill should be compacted by mechanical means in uniform horizontal lifts of 6 to 8- inches in thickness. All fill should be compacted to a minimum relative compaction L 'L HETHERINGTON ENGINEERING, INC. C 7' GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 �-- April 7,2006 Page 8 of 90-percent based upon ASTM: D - p 1557 02. The on-site materials are suitable for use as compacted fill provided all vegetation and debris are removed. Rock fragments over 6-inches in dimension and other perishable or unsuitable materials should be excluded from the fill. All grading and compaction should be observed and tested as necessary by the Geotechnical Engineer. 5. Foundation and Slab Recommendations The proposed two-story addition may be supported on conventional continuous/spread footings founded at least 18-inches into compacted fill and/or terrace deposits, should be at least 15-inches wide, and reinforced with a minimum of _ two #4 bars, one top and one bottom. The proposed garage/storage shed and storage l shed may be supported on conventional continuous/spread footings founded at least l 12-inches into compacted fill and/or terrace deposits, should be at least 12-inches wide and reinforced with a minimum of two #4 bars, one top and one bottom. Foundations located adjacent to utility trenches should extend to below a 1:1 plane projected upward from the bottom of the trench. Foundations bearing as recommended may be designed for a dead plus live load bearing value of 2000-pounds-per-square-foot. This value may be increased by one- third for loads including wind and seismic forces. A lateral bearing value of 250- pounds-per-square-foot per foot of depth and a coefficient of friction between foundation soil and concrete of 0.35 may be assumed. These values assume that footings will be poured neat against the foundation soils. Footing excavations should be observed by the Geotechnical Consultant prior to the placement of reinforcing steel in order to verify that they are founded in suitable bearing materials. Slab-on-grade floors should have a minimum thickness of 4-inches (actual) and should be reinforced with at least#3 bars spaced at 18-inches, center-to-center, in two directions, supported on chairs so that the reinforcement is at mid-height in the slab. Floor slabs should be underlain by a 4-inch thick layer of sand with a 10-mil visqueen moisture barrier placed in the middle of the sand layer. Prior to placing concrete, the slab subgrade soils should be thoroughly moistened. 1 6. Sulfate Content L Representative samples of the on-site soils were submitted for sulfate analyses. The results of the soluble sulfate tests per EPA 9038 method are presented on the attached Laboratory Tests Results, Figure 5. The sulfate content of the on-site soils is consistent with a negligible to severe sulfate exposure classification per Table 19-A-4 HETHERINGTON ENGINEERING, INC. At ,n TT _I GEOTECHNICAL INVES Project No. 5429.1 TIGATION Log No. 993 7 LJ April 7, 2006 Page 9 California Building Code. It is recommended that all concrete to be in of the 2001 contact with soil be designed for severe sulfate exposure classification per Table 19- A-4 of the 2001 California Building Code. 7. Retainin Walls Retaining walls free to rotate (cantilevered walls) should be designed for an active pressure of 35-pounds-per-cubic-foot (equivalent fluid pressure) assuming level t j backfill consisting of onsite granular soils. Walls restrained from should be designed for an additional uniform soils pressure of 8xH pounds ter square foot where H is the height of the wall in feet. Any additional surcharge pressures behind retaining walls should be added to these should be designed in accordance with the foundation Retaining recommendations foundations ovide -� previously in this report for the garage/storage shed and storage shed structures. Retaining walls should be provided with adequate drainage to prevent buildup of hydrostatic pressure and should be adequately waterproofed. The subdrain behind retaining walls should consist at a minimum of 4-inch diameter S hedulet 40 (or equivalent) perforated (perforations "down") PVC pipe embedded in at least 1- cubic-foot of 3/4 inch crushed rock per lineal foot of pipe all wrapped in approved filter fabric. Recommendations for wall waterproofing should be provided by the Project Architect and/or Structural Engineer. 8. Retainin - Wall and Utility Trench Backfill All retaining wall and utility trench backfill should be percent relative compaction (ASTM: D 1557-02). Backflllshou d be at 90- r observed by the Geotechnical Consultant. and 9. Site Draina P The following recommendations are intended to effects of water on the structures and appurtenances. minimize the potential adverse tJ.. a. Consideration should be given to providing downspouts that discharge to an area drain system structures/or to u stab tab gutters and away from the structures. le locations b. All site drainage should be directed away from the structures. ( generally sandy .in nature and considered erodible if exposed On-site to concentrated drainage. L HETHERING TON ENGINEERING, INC. i i �— GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 �-� April 7, 2006 Page 11 Our investigation was performed using the degree of care and skill ordinarily exercised, ed, under similar circumstances, by reputable Geotechnical Consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the conclusions and professional advice included in this report. 1 . This opportunity to be of service is sincerely appreciated. If you have any questions, —F please call this office. i r_ Sincerely, Hetherington Engine g, Inc. I_ pFESS/ 4 0 anny Cohen pY C0 a Hamelehle Registered Civil Engine 937 fessional Geologist 55 Geotechnncal Engineer No,2346 ified Engineering G l (expires 03/31/08) Ev. - pires 12/31/07) N06 IM _L TFOF CALW�� OBOLOOR�T C Attachments: Location``Iv1ap Figure 1 Plot Plan Figure 2 �CAu [ Boring Logs Figures 3 and 4 Laboratory Test Results Figures 5 LDistribution: Addressee (3) _L HETHERINGTON ENGINEERING, INC. REFERENCES �--- 1. Abbott, P., L., edited, "On the Manner of Deposition of the Eocene cene Strata in Northern San Diego County", San Diego Association of Geologists, Guidebook April 13, 1985. 2. Aerial Photographs, Flight GS-VBTA, Photos 1-174 and 1-175, dated May 8, 1967. 3. Cao, Tianging, et al, "The Revised 2002 California Probabilistic Seismic Hazard - Maps,"dated June 2003. T 4. Chereskin Architecture, "Haggbloom/Page Residence Site and Architectual Plans", dated October 26, 2005. 5. Encinitas Ortho and Topo Map, Flight Date July 2001, Map Coordinates - Stateplate NAD83 Feet, CA Zone 6, 1-inch equals 20-feet. 6. ICBO, California Building Code, 2001 Edition. 7. ICBO, "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada", dated February,1998. 8. Jennings, Charles W., "Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Map No. 6", 1994. 9. Kern, Philip and Rockwell, Thomas, K., "Chronology and Deformation of Quaternary Marine Shorelines, San Diego County, California", South Coast Geological Society, Inc., Annual Field Trip Guide de Book No. 20, 1992. 10. Peterson, M., Beeby, W., Bryant, W., et al., "Seismic Shaking Hazard Maps of California, California Division of Mines and Geology,Map Sheet 48", 1999. 11. "Probabilistic Seismic Hazard Assessment for the State of California", DMG Open-File Report 96-08 and USGS Open-File Report 96-706, 1996. 12. Tan, Siang S. and Giffen, Desmond G., "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California," Landslide Hazard Identification Map No. 35, California Division of Mines and Geology, 1995. -�—� 13. Tan, Siang S. and Kennedy, Michael P., "Geologic Maps of the Northwestern Part of San Diego County, California, Plate V, California Division of Mines and Geology, Open-File Report 96-02, 1996. Project No.5429.1 HETHERINGTON ENGINEERING, INC. Log No.9937 ---. REFERENCES 14. Treiman, Jerome A., "The Rose Canyon Fault Zone, Southern California", California Division of Mines and Geology, Open-File Report 93-02. 15. Weber, Harold F., Jr., "Recent Slope Failures, Ancient Landslides and Related �.-�- Geology of the North-Central Coastal Area, San Diego County, California", California Divisions of Mines and Geology, Open-File Report 82-12L, 1982. j Project No.5429.1 Log No.9937 HETHERINGTON ENGINEERING, INC. f � f f I ] 1 HA.2. t d \ —j'--X-' 1 I 1 LEGEND ] HA.3& APPROXIMATE LOCATION OF HAND AUGER BORING ` - Ri tr ' o0---- 30 40 PLOT PLAN 430 Andrew Avenue HETHERINGTQN ENGINEERING, INC. Encinitas, Caliibmia GEOTECHNICAL CONSULTANTS PROJECT NO. 5429.1 FIGURE NO. 2 ' ' J DRILLING COMPANY:HEI RIG: Hand Auger DATE: 02/15/06 } BORING DIAMETER: 6" DRIVE WEIGHT: DROP: H _ w N M w D z SOIL DESCRIPTION P4 Q a >-4 s 2 o 0 a BORING NO. HA-'I ELEVATION: 126 t 0.0 SM FILL: Dark brown, silty to clayey fine to medium sand, very SC moist, loose TERRACE DEPOSITS: Red brown, silty fine to medium sand, moist, medium dense 110 9.7 109 11.4 5.0 @ 5': Becomes yellow orange, silty fine to medium sand, moise, dense 110 11.9 Total depth 7 feet No water No caving 10.0 0.0 BORING NO. HA-2 ELEVATION: 112 t SM FILL: Brown silty fine to medium sand, damp, loose -x @ 1.5': Becomes brown, gravelly to silty fine to medium sand, damp, loose 5.0— Total depth 4 feet(refusal on roots) No water Minor caving or gravelly soils 10.0 -� BORING LOG 430 Andrew Avenue HETHERINGTON ENGINEERING, INC. Encinitas, California GEOTECHNICAL CONSULTANTS PROJECT NO. 5429.1 I FIGURE NO. 3 DRILLING COMPANY:HEI RIG: Hand Auger DATE: 02/15/06 BORING DIAMETER: 6" DRIVE WEIGHT: DROP: w a o H cn w x � A H W U U SOIL DESCRIPTION E' x 3 w Cn H a m fx w w >+ U H RH °7. H H _E; BORING NO. HA-3 ELEVATION: 108 t 0.0 ' SM FILL: Dark brown to brown, silty fine to medium sand, damp, loose TERRACE DEPOSITS: (Weathered) Red brown, silty fine to 101 3.9 medium sand, damp, loose to medium dense, some pinholes @ T: Becomes less weathered, no pinholes r 100 2.9 @ 4': Becomes yellow orange 5.0 @ 5': Becomes red orange and dense ' 107 8.9 r 1. Total depth 8 feet No water 10.0 No caving BORING LOG 430 Andrew Avenue 1 L HETHERINGTON ENGINEERING, INC. Encinitas, California GEOTECHNICAL CONSULTANTS PROJECT NO. 5429.1 FIGURE NO. 4 I l� LABORATORY RESULTS SULFATE.TEST RESULTS (EPA 9038) r Sam`` le Location; Soliuble Sulfate n Soil ' HA-1@3'-6' 1.32 HA-3@2'-4' 0.0216 EXPANSION INDEX (ASTM: D'4829) C t Sample Initial Compacted ]Final:,, Expansion Expansion ansion Inde Potential Mbiture ocation Dry Moisture (%) Density c HA-3@2"-4' 7.5 113 15.2 1 0 Very low MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT DETERMINATION (ASTMi D'155'7-02A) Sample Description Maximum Dry Optimum Moisture Location Density c Content % C_ HA-1 @3'-6' Light brown, fine to 124.0 7.5 medium sand 1. _L DIRECT SHEAR (ASTMS D 3080) Sample Angle of Internal Cohesion (Ps, Remarks Location Friction ° HA-1 @ 3'-6' 32 125 Remolded to 90%@ opt.,soaked, ( consolidated and drained QFigure t Project No.54, Log No.9 nowi _ , HYDROLOGY CALCULATIONS r� [`p For ; � E G �� V E HAGGBLOM RESIDENCE JUL 5 APN: 216-063-33 ENGINEERING SERVICES CITY Of ENCINITAS CITY OF ENCINITAS, CALIFORNIA Prepared For Candy Haggblom 430 Andrew Ave. Encinitas, CA 92024 PE 1498 PREPARED BY: PASCO ENGINEERING, INC. 535 N. HIGHWAY 101, SUITE A SOLANA BEACH, CA 92075 o��oFESS,o (858)259-8212 JUS r/4,,s�fr� DATE: 5-23-06 s n REVISED: * 6 9 4 E CIVIL CALIFdR�`P W. JUS SUITER,RCE 68964 DATE NAlydrology&HydraulicsX1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 TABLE OF CONTENTS SECTION DISCUSSION..............................................................................A CONCLUSION.............................................................................B 100 YEAR PRE DEVELOPMENT HYDROLOGY CALCULATIONS.........C 100 YEAR POST DEVELOPMENT HYDROLOGY CALCULATIONS .......D APPENDIX.................................................................................F Isopluvials Intensity Duration Curve SCS Soil Classification Node Map NAHydrology&Hydraulics11498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 A. INTRODUCTION The purpose of this report is to analyze the storm water runoff produced from the 100 year storm event of the existing and post-developed condition of the Andrew Ave. proposed project site. The subject property is physically located at 430 Andrew Ave., Encinitas, California. The property is geographically located at N 33°04'00" W 117017'00". Pre-Developed Conditions The existing condition of the project site consists of an existing house at 430 Andrew Avenue. The house is located on the elevated south side of the lot. A private drive servicing homes to the north runs parallel along the western property line. Slopes from the property to the road way are steep and covered in concrete riprap. Immediately behind the house is a concrete patio and pond. The middle portion of the lot contains raised planter boxes with concrete hardscape between them providing walkways. A series of metal sheds and concrete walkways makes up the middle section of the western border. Natural vegetation and fruit trees make up the northern most portion of the lot. The highpoint of the property occurs in the south-east corner of the property at 135.2'. The low point of the property occurs in the north-west corner at an elevation of 101.1 . The difference in elevation between the high and low point on the property is 34.1'. the existing condition for drainage onsite is sheet flow from south to north. For the existing 100 year flows the property was divided into three separate drainage hydrologic sub- basins. They are basins Al, A2, and A3. Drainage sub-basins produced peak flows of 0.26 cfs, 0.82 cfs, and 1.41 cfs. Post- Development Conditions The proposed development consists of the construction of a garage and storage facility. Runoff from the proposed structure will be caught and directed over BMP area before it leaves the site. Runoff from the rest of the property will continue to follow its current path to leave the site. A series of area drains will collect runoff from behind the proposed retaining wall. This runoff will then gravity flow to a discharge point on the wall to a proposed driveway/ramp. From there the runoff will travel over designated BMP area. The total post-development flows for area Al, A2, and A3 are 0.26 cfs, 0.85 cfs, and 1.45cfs. When compared with existing conditions, the difference in total flows for pre-development and post-development is negligible. Therefore, no detention structure is proposed for this development. N:1Hydrology&HydraulicsN1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 Methodology and Results Introduction The hydrologic model used to perform the hydrologic analysis presented in this report utilizes the Ration Method (RM) equation, Q=CIA. The RM formula estimates the peak rate of runoff based on the variables of area, runoff coefficient, and rainfall intensity. The rainfall intensity(I)is equal to: I= 7.44 x P6 x D"" Where: I=Intensity(in/hr) P6 =6-hour precipitation(inches) D=duration(minutes—use Tc) Using the Time of Concentration (Tc), which is the time required for a given element of water that originates at the most remote point of the basin being analyzed to reach the point at which the runoff from the basin is being analyzed. The RM equation determines the storm water runoff rate (Q) for a given basin in terms of flow (typically in cubic feet per second (cfs) but sometimes as gallons per minute (gpm)). The RM equation is as follows: Q=CIA Where: Q=flow(in cfs) C=runoff coefficient, ratio of rainfall that produces storm water runoff(runoff vs. infiltration/evaporation/absorption/etc) I=average rainfall intensity for a duration equal to the Tc for the area, in inches per hour. A=drainage area contributing to the basin in acres. The RM equation assumes that the storm event being analyzed delivers precipitation to the entire basin uniformly, and therefore the peak discharge rate will occur when a raindrop that falls at the most remote portion of the basin arrives at the point of analysis. The RM also assumes that the fraction of rainfall that becomes runoff or the runoff coefficient C is not affected by the storm intensity, I,or the precipitation zone number. The hydrologic soil group classification for the site is"D". The methodology used herein to determine Qloo is the modified rational method. The computer modeling program utilized to perform the hydrologic analysis of the proposed project site is produced by Advanced Engineering Software(AES2003). The pre and post-development runoff coefficients, used to analyze the both conditions, were determined by using weighted"C" average. NAHydrology&Hydraulics11498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 C=0.90 z(% impervious)+ Cp x(1-%impervious) Where: Cp = pervious surface runoff coeffcient (varies depending on soil type from 0.2 to 0.35—since analysis assumes type d soils Cp x.35) For the proposed development the runoff coefficient utilized for the hydrologic analysis of the project site was calculated to be 0.71, based on an impervious percentage of 64.6%. For the pre-developed condition the runoff coefficient utilized for the hydrologic analysis of the project site was calculated to be 0.69, based on an impervious percentage of 62.2%. B. CONCLUSION Based on the information and calculations contained in this report it is the professional opinion of Pasco Engineering, Inc. that the storm drain system as proposed on the corresponding Grading Plan will function to adequately intercept, contain and convey QIoo to the appropriate points of discharge. N:Wydrology&HydraulicsX1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 C. 100 YEAR PRE DEVELOPMENT HYDROLOGY CALCULATIONS N:\Hydrology&Hydraulics11498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference:SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2001,1985,1981 HYDROLOGY MANUAL (c)Copyright 1982-2002 Advanced Engineering Software(aes) Ver. 1.5A Release Date:01/01/2002 License ID 1452 Analysis prepared by: Pasco Engineering,Inc. 535 N.Highway 101,Suite A Solana Beach,CA 92075 ssssssssssssssssssssssssss DESCRIPTION OF STUDY sssssss sssssssss sssssssssssssssssssssssssss predevelopmernt hydrologic analysis 100 year storm s : s : ssssssssssssssssssssssssssssssssssssss sssssssssssssssssssss sss sssssssssssssssssssssssssssssss FILE NAME: 1498PRE.DAT TIIv1FF ./DATE OF STUDY: 15:32 05/22/2006 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR)=100.00 6-HOUR DURATION PRECIPITATION(INCHES)= 3.000 _ SPECIFIED MINIMUM PIPE SDE(INCH)= 3.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL)TO USE FOR FRICTION SLOPE=0.95 SAN DIEGO HYDROLOGY MANUAL"C"-VALUES USED FOR RATIONAL METHOD NOTE:ONLY PEAK CONFLUENCE VALUES CONSIDERED *USER DEFINED STREET SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSSFALL IN- /OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE/SIDE/WAY (FT) (FT) (FT) (FT) (n) 1 30.0 20.0 0.01810.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS: 1.Relative Flow-Depth= 0.00 FEET as(Maximum Allowable Street Flow Depth)-(To"f-Curb) 2.(Depth)*(Velocity)Constraint= 6.0(FT=FT/S) =SIZE PIPE WITH A FLOW CAPACITY GREATER THAN OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.* NAHydrology&Hydraulics11498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGG13LOM RESIDENCE PE 1498 FLOW PROCESS FROM NODE 1.10 TO NODE 1.00 IS CODE= 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT=.6900 S.C.S.CURVE NUMBER(AMC II)= 0 INITIAL,SUBAREA FLOW-LENGTH= 100.00 UPSTREAM II EVATION= 13520 DOWNSTREAM ELEVATION= 126.70 ELEVATION DIFFERENCE= 8.50 URBAN SUBAREA OVERLAND TDAE OF FLOWQANUTFS)= 3.616 *CAUTION:SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION.EXTRAPOLATION OF NOMOGRAPH USED. TIME OF CONCENTRATION ASSUMED AS 6-NflNUT ES 100 YEAR RAINFALL INTENSITY(INCIMOUR)= 7.027 SUBAREA RUNOFF(CFS)= 0.26 TOTAL AREA(ACRES)= 0.05 TOTAL RUNOFF(CFS)= 0.26 FLAW PROCESS FROM NODE 1.00 TO NODE 2.0015 CODE= 51 »»>COMPUTE TRAPEZOIDAL CHANNEL FLOW««< »»>TRAVELTIIviE THRU SUBAREA(EXISTING ELEM ENT)««< ELEVATION DATA:UPSTREAM(FEET)= 126.70 DOWNSTREAM(FEET)= 118.00 CHANNEL LENGTH THRU SUBAREA(FEET)= 73.00 CHANNEL SLOPE= 0.1192 CHANNEL,BASE(FEET)= 4.00 'Z"FACTOR= 2.000 MANNING"S FACTOR=0.015 MAX MUM DEPTH(FEET)=500.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR)= 6.678 *USER SPECIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT=.6900 S.C.S.CURVE NUMBER(AMC II)= 0 TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS)= 0.26 TRAVEL.,TDAE THRU SUBAREA BASED ON VELOCITY(FEETISEC.)= 2.46 AVERAGE FLOW DEPTH(FEET)= 0.03 TRAVEL TIl HVAN.)= 0.49 Tc(MIN.)= 6.49 SUBAREA AREA(ACRES)= 0.00 SUBAREA RUNOFF(CFS)= 0.00 TOTAL AREA(ACRES)= 0.05 PEAK FLOW RATE(CFS)= 026 END OF SUBAREA CHANNEL FLOW HYDRAULICS: DEPTH(FEET)= 0.03 FLAW VEIACITY(FEET/SEC.)= 2.46 LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.00= 173.00 FEET. FLOW PROCESS FROM NODE 2.10 TO NODE 2.00 IS CODE= 81 »»>ADDTTION OF SUBAREA TO MAINLINE PEAK FLOW««< 100 YEAR RAINFALL INTENSITY(INCH/HOUR)= 6.678 *USER SPF.CIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT=.6900 S.C.S.CURVE NUMBER(AMC In= 0 SUBAREA AREA(ACRES)= 0.18 SUBAREA RUNOFF(CFS)= 0.82 TOTAL AREA(ACRES)= 0.23 TOTAL RUNOFF(CFS)= 1.08 TC(IbIL1Q)= 6.49 NAHydrology&Hydraulics\1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 FLOW PROCESS FROM NODE 2.00 TO NODE 3.00 IS CODE= 51 »»>COMPUTE TRAPEZOIDAL CHANNEL FLOW««< >>>>>TRAVELT MF-THRU SUBAREA(EXISTING ELEMENT)<«« ELEVATION DATA:UPSTREAM(FEET)= 118.00 DOWNSTREAM(FEET)= 101.50 CHANNEL LENGTH THRU SUBAREA(FEET)= 100.00 CHANNEL SLOPE= 0.1650 CHANNEL BASE(FEET)= 4.00 W FACTOR= 2.000 MANNING'S FACTOR=0.015 MAXIMUM DEPTH(FEET)=500.00 100 YEAR RAINFALL INTENSTIY(INCH/HOUR)= 6.482 *USER SPECIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT=.6900 S.C.S.CURVE NUMBER(AMC Il)= 0 TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS)= 1.08 TRAVEL TR,4E THRU SUBAREA BASED ON VELOCTIY(FEET/SEC.)= 5.43 AVERAGE FLOW DEPTHRIM)= 0.05 TRAVEL TIME(MIN.)= 0.31 Tc(MN'.)= 6.80 SUBAREA AREA(ACRES)= 0.00 SUBAREA RUNOFF(CFS)= 0.00 TOTAL AREA(ACRES)= 0.23 PEAK FLOW RATE(CFS)= 1.08 END OF SUBAREA CHANNEL FLOW HYDRAULICS: DEPTH(FEET)= 0.05 FLOW VELOCITY(FEET/SEC.)= 5.43 LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.00= 273.00 FEET. FLOW PROCESS FROM NODE 3.10 TO NODE 3.00 LS CODE= 81 »»>ADDMON OF SUBAREA TO MAINLM PEAK FLOW««< 100 YEAR RAINFALL INTENSITY(INCH/HOUR)= 6.482 *USER SPECIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT=.6900 S.G.S.CURVE NUMBER(AMC H)= 0 SUBAREA AREA(ACRES)= 031 SUBAREA RUNOFF(CFS)= 1.41 TOTAL AREA(ACRES)= 0.55 TOTAL RUNOFF(CFS)= 2.49 TC(MIN)= 6.80 END OF STUDY SUMMARY: TOTAL AREA(ACRES) = 0.55 TC(M[N.)= 6.80 PEAK FLOW RATE(CFS) = 2.49 N:\Hydrology&Hydraulics\1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 D. 100 YEAR POST DEVELOPMENT HYDROLOGY CALCULATIONS N:Wydrology&Hydraulics\1498 HYDRO REPORT.doc PE#1498 9:58 AM 5123/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 **************************************************************************** RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2001,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2002 Advanced Engineering Software (aes) Ver. 1.5A Release Date: 01/01/2002 License ID 1452 Analysis prepared by: Pasco Engineering, Inc. 535 N. Highway 101, Suite A Solana Beach, CA 92075 ************************** DESCRIPTION OF STUDY ************************** * post development hyrologic analysis 100 year storm * * FILE NAME: 1498POST.DAT TIME/DATE OF STUDY: 15:39 05/22/2006 ---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: ---------------------------------------------------------------------------- 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 3.000 SPECIFIED MINIMUM PIPE SIZE(INCH) = 3.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD - NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS: 1. Relative Flow-Depth = 0.00 FEET as (Maximum Allowable Street Flow Depth) - (Top-of-Curb) 2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S) *SIZE PIPE WITH A FLOW CAPACITY GREATER THAN OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.* NAHydrology&Hydraulics\1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGG13LOM RESIDENCE PE 1498 FLOW PROCESS FROM NODE 1.10 TO NODE 1.00 IS CODE = 21 ---------------------------------------------------------------------------- »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA) : USER-SPECIFIED RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0 INITIAL SUBAREA FLOW-LENGTH = 100.00 UPSTREAM ELEVATION = 135.20 DOWNSTREAM ELEVATION = 126.70 ELEVATION DIFFERENCE = 8.50 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 3.440 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. TIME OF CONCENTRATION ASSUMED AS 6-MINUTES 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.027 SUBAREA RUNOFF(CFS) = 0.26 TOTAL AREA(ACRES) = 0.05 TOTAL RUNOFF(CFS) = 0.26 FLOW PROCESS FROM NODE 1.00 TO NODE 2.00 IS CODE = 51 ---------------------------------------------------------------------------- »»>COMPUTE TRAPEZOIDAL CHANNEL FLOW««< »»>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)««< ELEVATION DATA: UPSTREAM(FEET) = 126.70 DOWNSTREAM(FEET) = 118.00 CHANNEL LENGTH THRU SUBAREA(FEET) = 73.00 CHANNEL SLOPE = 0.1192 CHANNEL BASE(FEET) = 4.00 °Z° FACTOR = 2.000 MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 500.00 - 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.687 *USER SPECIFIED(SUBAREA) : USER-SPECIFIED RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0 - TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 0.26 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.53 AVERAGE FLOW DEPTH(FEET) = 0.03 TRAVEL TIME(MIN.) = 0.48 Tc(MIN.) = 6.48 SUBAREA AREA(ACRES) = 0.00 SUBAREA RUNOFF(CFS) = 0.00 TOTAL AREA(ACRES) = 0.05 PEAK FLOW RATE(CFS) = 0.26 END OF SUBAREA CHANNEL FLOW HYDRAULICS: DEPTH(FEET) = 0.03 FLOW VELOCITY(FEET/SEC.) = 2.53 LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.00 = 173.00 FEET. FLOW PROCESS FROM NODE 2.10 TO NODE 2.00 IS CODE = 81 ---------------------------------------------------------------------------- »»>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW««< - 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.687 *USER SPECIFIED(SUBAREA) : USER-SPECIFIED RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0 SUBAREA AREA(ACRES) = 0.18 SUBAREA RUNOFF(CFS) = 0.85 TOTAL AREA(ACRES) = 0.23 TOTAL RUNOFF(CFS) = 1.11 TC(MIN) = 6.48 N:1Hydrology&Hydraulics11498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGG13LOM RESIDENCE PE 1498 FLOW PROCESS FROM NODE 2.00 TO NODE 3.00 IS CODE = 51 ---------------------------------------------------------------------------- »»>COMPUTE TRAPEZOIDAL CHANNEL FLOW««< »»>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)««< _---------------------_------------------------ ELEVATION DATA: UPSTREAM(FEET) = 118.00 DOWNSTREAM(FEET) = 101.50 CHANNEL LENGTH THRU SUBAREA(FEET) = 100.00 CHANNEL SLOPE = 0.1650 CHANNEL BASE(FEET) = 4.00 "Z" FACTOR = 2.000 MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 500.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.488 *USER SPECIFIED(SUBAREA) : USER-SPECIFIED RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0 TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.11 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 5.38 AVERAGE FLOW DEPTH(FEET) = 0.05 TRAVEL TIME(MIN.) = 0.31 Tc(MIN.) = 6.79 SUBAREA AREA(ACRES) = 0.00 SUBAREA RUNOFF(CFS) = 0.00 TOTAL AREA(ACRES) = 0.23 PEAK FLOW RATE(CFS) = 1.11 END OF SUBAREA CHANNEL FLOAT HYDRAULICS: DEPTH(FEET) = 0.05 FLOW VELOCITY(FEET/SEC.) = 5.38 LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.00 273.00 FEET. - FLOW PROCESS FROM NODE 3.10 TO NODE 3.00 IS CODE = 81 ---------------------------------------------------------------------------- »»>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW««< 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.488 *USER SPECIFIED(SUBARF.A) : USER-SPECIFIED RUNOFF COEFFICIENT = .7100 S.C.S. CURVE NUMBER (AMC II) = 0 SUBAREA AREA(ACRES) = 0.31 SUBAREA RUNOFF(CFS) = 1.45 TOTAL AREA(ACRES) = 0.55 TOTAL RUNOFF(CFS) 2.57 TC(MIN) = 6.79 - END OF STUDY SUMMARY: TOTAL AREA(ACRES) = 0.55 TC(MIN.) = 6.79 PEAK FLAW RATE(CFS) = 2.57 -------------__------------ -____=_ END OF RATIONAL METHOD ANALYSIS NAHydrology&Hydraulics\1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 HYDROLOGY STUDY for HAGGBLOM RESIDENCE PE 1498 F. APPENDIX N:\Hydrology& Hydraulics\1498 HYDRO REPORT.doc PE#1498 9:50 AM 5/23/2006 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ct 45 C4 Wi Imperial County SLALL Aso- MML tar _ C3 it C3 cn 30 C2 o Imperial County .......... F4 . ........... ....... ........... .......... ........... cV .......... zq.................... ':.............. ....... ............ St.9 L L .......... 0 .... . ...... M.LLL cu od 0 ct) 0 G 95 115' AE.1 L L XE.L L �is��t��a�_/11--�lI�li.�.—Rf..N.RI Yatdi♦�S t� ��.� —/ ltI/��•� �i�••....t A/aaYYltlrtat! 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W U N O d U U d .d b .M •� R R L' U rn 64 64 P c 94 u u c c c c C yam' a' c _... U N b �' �' u 60i d d .l'....' ' A m y C 3 •cs ocw n 'c 'c �►-. A A A a � � a A A � u � a u � •� � A � A � c o c 3 d v d u C 'Coo o � _°o � v�A a .a .-� .S aC x U U U U U c°> .� C] z � t 3 f < f i al 4A lj� R -ti $ L L ci w I � o Lj lu N _ti*-f , o: Wei t LIS Ek LJ cu z u I r N N `� �._al l► � it I! r t 'Y- h , p N v�pp �2 GEOTECHNICAL INVESTIGATION Proposed Building Addition, New Garage and Shed 430 Andrew Avenue Encinitas, California t' at ENGINEERM SERVICES CITY OF ENCINITAS April 7, 2006 Project No. 5429.1 Log No. 9937 Ms. Virginia Page 430 Andrew Avenue Encinitas, CA 92024 Subject: GEOTECHNICAL INVESTIGATION Proposed Building Addition,New Garage and Shed 430 Andrew Avenue Encinitas, California References: Attached Dear Ms. Page: In accordance with your request, we have performed a geotechnical investigation at the subject site. Our work was performed in February through April 2006. The purpose of our investigation was to evaluate geologic and soil conditions within the area of the proposed building addition, new backyard garage/storage shed and storage shed and to provide grading and foundation recommendations for these proposed structures. No specific development plans were available for review at the time of this report. Our scope of work included the following: • Research and review of available plans, geologic literature and aerial photographs pertinent to the site(see References). • Subsurface exploration consisting of three exploratory hand-auger borings for soil/bedrock sampling and geologic observation. • Laboratory testing of samples obtained from the subsurface exploration. • Engineering and geologic analysis. • Preparation of this report providing the results of our field and laboratory work, analyses, and our conclusions and recommendations. SITE DESCRIPTION The subject property is located at 430 Andrew Avenue, Encinitas, California (see Location Map, Figure 1). The lot is bounded by Andrew Avenue on the south, a private A TIOUI TOS LAGOON SITE a ; <�� , — AV tAw ' �Ur H T r 7 x d PS II� ate' r •'!j yfin�Y �.i1��+� 4� '� «, � � �� ,�� 33 wi} o #f 4L + t" ( Y[AN y.a 0P r y, o, -. G t sutc�+ rry A3 n ` L# 0 t ... _ r �.._ (y _ �F '. ,J. da. �{�( ✓ 'fly. f LEUCADIA VIM- LLWkiS41JIA EfkYkYS .wv ar ., ! f4 x' v' } M L ATM WON r .6y` 1' SPEPS s.• t �rWt'. �� AlYa.s(3 � �jI ST ^ff ADAPTED FROM: The Thomas Guide,San Diego County,2004 Edition N SCALE: 1"-2000' (1 Grid=0.5 x 0.5 miles) LOCATION MAP 430 Andrew Avenue HETHERINGTON ENGINEERING, INC. Encinitas, California GEOTECHNICAL CONSULTANTS PROJECT NO. 5429.1 1 FIGURE NO. 1 GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 2 driveway on the west, and existing residential structures on the north and east. The lot consists of a rectangular shaped parcel that slopes gently to the north and presently supports a two-story, wood-frame residence that appears to be supported by conventional continuous footings with either raised wood or slab-on-grade floors. The back yard contains several sheds and various fruit trees, planter beds and a small swimming pool. Landscaping around the existing residence consists of various trees and bushes. Concrete driveways, flatwork and concrete pavers also cover relatively large portions of the backyard area. The front concrete driveway covers most of the front yard and west side yard and connects Andrew Avenue with the adjacent private driveway. PROPOSED DEVELOPMENT Based upon our discussions with you and our review of a copy of the site plan provided by Chereskin Architecture, we understand that proposed site improvements consist of a two-story addition at the north and west sides of the existing residence and the construction of a garage/storage shed structure and a separate storage shed in the central portion of the lot. We anticipate that the proposed structures will be of wood-frame construction and building loads are expected to be typical for this type of relatively light construction. Site grading is expected to be minor. SUBSURFACE EXPLORATION Subsurface conditions were explored by manually advancing three hand-auger borings to depths of approximately 4 to 8-feet below existing site grades. The approximate locations of the hand-auger borings are shown on the attached Plot Plan, Figure 2. The subsurface exploration was supervised by a geologist from this office, who visually classified the soil and formational materials, and obtained bulk and relatively undisturbed samples for laboratory testing. The soils were visually classified according to the Unified Soil Classification System. Classifications are shown on the attached Boring Logs, Figures 3 and 4. LABORATORY TESTING Laboratory testing was performed on samples obtained during the subsurface exploration. Tests performed consisted of the following: • Dry Density/Moisture Content(ASTM: D 2216) • Sulfate Content(EPA 9038) GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 3 • Expansion Index(ASTM: D 4829) • Maximum Dry Density/Optimum Moisture Content(ASTM: D 1557) • Direct Shear(ASTM: D 3080) Results of the dry density and moisture content determinations are presented on the Boring Logs, Figures 3 and 4. The remaining laboratory test results are presented on the attached Laboratory Test Results, Figure 5. SOIL AND GEOLOGIC CONDITIONS 1. Geologic Setting The subject site lies within the marine terrace commonly known as the Palomar Terrace that is contained within the coastal plain region of northern San Diego County, California. The coastal plain region is characterized by numerous regressive marine terraces of Pleistocene age that have been established above wave-cut platforms of underlying Eocene bedrock and were formed during glacio-eustatic changes in sea-level. The terraces extend from areas of higher elevations east of the site and descend generally west-southwest in a"stairstep" fashion down to the present day coastline. These marine terraces increase in age eastward. The Palomar Terrace is the third youngest terrace after the Bird Rock and Nestor Terraces. The site area is contained within the north central portion of the USGS Encinitas 7-1/2 minute quadrangle. The Palomar Terrace, a Pleistocene marine terrace, underlies the entire site. The Scripps Formation is exposed to the north of the site within the cliffs along the Batiquitos Lagoon and to the east and northeast within roadcut slopes. It is anticipated that this formation underlies the terrace deposits at depth. Structurally, bedding within the terrace deposits is considered to be essentially massive. Active fault zones within the general site region include the offshore extension of the Rose Canyon/Newport-Inglewood, Coronado Bank/Palos Verdes Hills and the Elsinore, which are located approximately 3.4-miles southwest, 17.5- miles southwest and 27.2-miles northeast from the site, respectively. No known or reported deep-seated landsliding is known to exist on the site. No known or reported active or potentially active faults exist within the site. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 4 2. Observed Geologic Units a. Fill - A relatively thin layer of fill was observed to overlie the Palomar Terrace within the areas planned for construction. The maximum observed thickness of fill was approximately 4-feet at Boring HA-2. It is anticipated that the fill thickness within areas of proposed site improvements will not exceed 5-feet. In general, the fill consisted of dark brown to brown, damp to moist, loose silty to slightly clayey fine to medium sand. The fill is not considered to be suitable for support of the proposed structures and will require removal and recompaction prior to the placement of compacted fill and/or construction of settlement sensitive site improvements b. Terrace Deposits - The entire site is underlain by the Palomar Terrace, a Pleistocene-age marine terrace deposit. The upper 1.5 to 2-feet of this unit was observed to be moderately weathered and the unit consists generally of red brown, fine to medium sand with some silt that is damp to very moist and medium dense to dense. At depth this unit becomes orange red brown and dense to very dense. 3. Groundwater Groundwater was not encountered in the hand-auger borings. It should be noted, however, that fluctuations in the amount and level of groundwater might occur due to variations in rainfall, irrigation and other factors that may not have been evident at the time of our field investigation. SEISMICITY The site is within the seismically active southern California region. There are, however, no known active faults located within or adjacent to the site. The La Costa Avenue fault is mapped approximately 700-feet east of the site, however, no evidence of offset within the last 11,000 years would indicate that this fault is not active. Active fault zones currently mapped within the general site region include the offshore extension of the Rose Canyon/Newport-Inglewood, offshore Coronado Bank/Palos Verdes Hills and the Elsinore, which are located approximately 3.4-miles (5.5-kilometers) southwest, 17.5- miles (28-kilometers) southwest and 27.2-miles (43.5-kilometers) northeast from the site, respectively. Strong ground motion could also be expected from earthquakes occurring along the offshore San Diego Trough, San Jacinto and San Andreas fault zones, which lie approximately 30-miles southwest, 48-miles northeast and 60 to 70-miles northeast of the site, respectively. The San Clemente fault, which lies approximately 50-miles southwest GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 5 of the site, as well as numerous other offshore faults, could also cause strong ground motion. The following table lists the known active faults that would have the most significant impact on the site: Maximum Probable Fault Earthquake Slip Rate Fault (Moment Magnitude) (mm/year) Type Rose Canyon 3.4-miles/5.5-kilometers S 7.2 1.5 B Coronado Bank/Palos Verdes Hills 17.5-miles/28-kilometers S 7.6 3 B Elsinore(Julian Segment) 27.2-miles/43.5-kilometers NE 7.1 5 A SEISMIC EFFECTS 1. Ground Motions The most significant probable earthquake to affect the property would be a 7.2 magnitude earthquake on the Rose Canyon/Newport-Inglewood fault. Depiction of probabilistic seismic hazard analysis utilizing a consensus of historical seismic data and the respective regional geologic conditions that are shown on "The Revised 2002 California Probabilistic Seismic-Hazard Maps" (Reference 3), indicates that peak ground accelerations of about 0.20 to 0.30g are possible with a 10% probability of being exceeded in 50-years. 2. Landslidina Review of the referenced geologic literature indicates that the subject property has no previously mapped ancient landslide deposits. The risk of seismically induced landsliding affecting the site is considered low due to the gently sloping topography. 3. Ground Cracks The risk of fault surface rupture due to active faulting is considered low due to the absence of an active fault on site. Ground cracks due to shaking from seismic events in the region are possible, as with all of southern California. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 6 4. Liquefaction The risk of seismically induced liquefaction within the site is considered low due to the lack of shallow groundwater and the relatively dense nature of the underlying terrace deposits. 5. Tsunamis The risk for seismically generated ocean waves to affect the site is considered low due to the elevation above sea level. CONCLUSIONS AND RECOMMENDATIONS 1. General The proposed building addition, backyard garage/storage shed and storage shed are considered feasible from a geotechnical standpoint. Grading and foundation plans should take into account the appropriate geotechnical features of the site. Assuming that the recommendations presented in this report and good construction practices are utilized during the design and construction, the proposed construction is not anticipated to adversely impact the adjacent properties from a geotechnical standpoint. 2. Seismic Parameters for Structural Desien Seismic considerations that should be used for structural design at the site include the following: a. Ground Motion —The proposed structures should be designed and constructed to resist the effects of seismic ground motions as provided in Chapter 16, Division IV of the 2001 California Building Code. The basis for the design is dependent on and considers seismic zoning, site characteristics, occupancy, configuration, structural system and building height. b. Soil Profile Type — In accordance with Section 1629.3.1, Table 16-J, and the underlying geologic conditions, a site Soil Profile of Type SD is considered appropriate for the subject property. c. Seismic Zone — In accordance with Section 1629.1 and Figure 16-2, the subject site is situated within Seismic Zone 4. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 7 d. Seismic Zone Factor (z) — A Seismic Zone Factor of 0.40 is assigned based on Table 16-1. Since the site is within Seismic Zone 4, Section 1629.4.2 requires a Seismic Source Type and Near Source Factor. e. Near-Source Factor (Na and Nv)—Based on the known active faults in the region and distance of the faults from the site, a Seismic Source Type of B per Table 16- U, and Near Source Factors of Na= 1.0 per Table 16-S and Nv = 1.18 per Table 16-T are provided. f. Seismic Coefficients (Ca and Cv)—Using the Soil Profile Type and Seismic Zone Factor along with Tables 16-Q and 16-R, the Seismic Coefficients Ca= 0.44 (Na) and Cv=0.64 (Nv) are provided, or Ca=0.44 and Cv=0.76. 3. Slope Stability The site is gently sloping to the north and no cut or fill slopes are anticipated, consequently, slope stability is not a design consideration. 4. Site Grading Prior to grading, the portions of the site where improvements are proposed should be cleared of existing surface obstructions, vegetation and debris. Materials generated during clearing should be disposed of at an approved location off-site. Holes resulting from the removal of buried obstructions should be backfilled with compacted fill. Old septic systems, if encountered, should be removed and backfilled in accordance with local regulations. Within the limits of the proposed structures, the existing fill soils and upper I to 2-feet of the terrace deposits should be removed down to approved terrace deposits and replaced with compacted fill in order to achieve final design finish grades. Removal depths are anticipated to extend approximately 2 to 5- feet below the existing grade. Following removals the exposed terrace deposits should be scarified to a depth of 6 to 8-inches, moisture conditioned to about optimum moisture content and compacted to at least 90-percent relative compaction. The recommended removals and compaction should extend to at least 5-feet outside the limits of proposed site improvements where practical. Actual removal depths should be determined in the field by the Geotechnical Consultant based on conditions exposed during grading. Fill should be compacted by mechanical means in uniform horizontal lifts of 6 to 8- inches in thickness. All fill should be compacted to a minimum relative compaction GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 8 of 90-percent based upon ASTM: D 1557-02. The on-site materials are suitable for use as compacted fill provided all vegetation and debris are removed. Rock fragments over 6-inches in dimension and other perishable or unsuitable materials should be excluded from the fill. All grading and compaction should be observed and tested as necessary by the Geotechnical Engineer. 5. Foundation and Slab Recommendations The proposed two-story addition may be supported on conventional continuous/spread footings founded at least 18-inches into compacted fill and/or terrace deposits, should be at least 15-inches wide, and reinforced with a minimum of two #4 bars, one top and one bottom. The proposed garage/storage shed and storage shed may be supported on conventional continuous/spread footings founded at least 12-inches into compacted fill and/or terrace deposits, should be at least 12-inches wide and reinforced with a minimum of two #4 bars, one top and one bottom. Foundations located adjacent to utility trenches should extend to below a 1:1 plane projected upward from the bottom of the trench. Foundations bearing as recommended may be designed for a dead plus live load bearing value of 2000-pounds-per-square-foot. This value may be increased by one- third for loads including wind and seismic forces. A lateral bearing value of 250- pounds-per-square-foot per foot of depth and a coefficient of friction between foundation soil and concrete of 0.35 may be assumed. These values assume that footings will be poured neat against the foundation soils. Footing excavations should be observed by the Geotechnical Consultant prior to the placement of reinforcing steel in order to verify that they are founded in suitable bearing materials. Slab-on-grade floors should have a minimum thickness of 4-inches (actual) and should be reinforced with at least#3 bars spaced at 18-inches, center-to-center, in two directions, supported on chairs so that the reinforcement is at mid-height in the slab. Floor slabs should be underlain by a 4-inch thick layer of sand with a 10-mil visqueen moisture barrier placed in the middle of the sand layer. Prior to placing concrete, the slab subgrade soils should be thoroughly moistened. 6. Sulfate Content Representative samples of the on-site soils were submitted for sulfate analyses. The results of the soluble sulfate tests per EPA 9038 method are presented on the attached Laboratory Tests Results, Figure 5. The sulfate content of the on-site soils is consistent with a negligible to severe sulfate exposure classification per Table 19-A-4 GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 9 of the 2001 California Building Code. It is recommended that all concrete to be in contact with soil be designed for severe sulfate exposure classification per Table 19- A-4 of the 2001 California Building Code. 7. Retaining Walls Retaining walls free to rotate (cantilevered walls) should be designed for an active pressure of 35-pounds-per-cubic-foot (equivalent fluid pressure) assuming level backfill consisting of onsite granular soils. Walls restrained from movement at the top should be designed for an additional uniform soils pressure of 8xH pounds per square foot where H is the height of the wall in feet. Any additional surcharge pressures behind retaining walls should be added to these values. Retaining wall foundations should be designed in accordance with the foundation recommendations provided previously in this report for the garage/storage shed and storage shed structures. Retaining walls should be provided with adequate drainage to prevent buildup of hydrostatic pressure and should be adequately waterproofed. The subdrain system behind retaining walls should consist at a minimum of 4-inch diameter Schedule 40 (or equivalent) perforated (perforations "down') PVC pipe embedded in at least 1- cubic-foot of 3/4 inch crushed rock per lineal foot of pipe all wrapped in approved filter fabric. Recommendations for wall waterproofing should be provided by the Project Architect and/or Structural Engineer. 8. Retaining Wall and Utility Trench Backfill All retaining wall and utility trench backfill should be compacted to at least 90- percent relative compaction (ASTM: D 1557-02). Backfill should be tested and observed by the Geotechnical Consultant. 9. Site Drainage The following recommendations are intended to minimize the potential adverse effects of water on the structures and appurtenances. a. Consideration should be given to providing the structures with roof gutters and downspouts that discharge to an area drain system and/or to suitable locations away from the structures. b. All site drainage should be directed away from the structures. On-site soils are generally sandy in nature and considered erodible if exposed to concentrated drainage. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 10 c. No landscaping should be allowed against the structures. Moisture accumulation or watering adjacent to foundations can result in deterioration of wood/stucco and may affect foundation performance. d. Irrigated areas should not be over-watered. Irrigation should be limited to that required to maintain the vegetation. Additionally, automatic systems must be seasonally adjusted to minimize over-saturation potential particularly in the winter(rainy) season. e. All yard and roof drains should be periodically checked to verify they are not blocked and flow properly. This may be accomplished either visually or, in the case of subsurface drains, placing a hose at the inlet and checking the outlet for flow. 10. Recommended Observation and Testing During Construction The following tests and/or observations by the Geotechnical Consultant are recommended: a. Observation and testing of grading. a. Foundation excavations prior to placement of forms and reinforcement. b. Utility trench backfill. c. Retaining wall backdrains and backfill. 11. Grading and Foundation Plan Review Final grading and foundation plans should be reviewed by the Geotechnical Consultant to confirm conformance with the recommendations presented herein or to modify the recommendations as necessary. LIMITATIONS The analyses, conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our investigation and further assume the excavations to be representative of the subsurface conditions throughout the site. If different subsurface conditions from those encountered during our exploration are observed or appear to be present in excavations, the Geotechnical Engineer should be promptly notified for review and reconsideration of recommendations. GEOTECHNICAL INVESTIGATION Project No. 5429.1 Log No. 9937 April 7, 2006 Page 11 Our investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Geotechnical Consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the conclusions and professional advice included in this report. This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely, Hetherington Engineering, Inc. Danny Cohen Dale Hamelehle Registered Civil Engineer 41937 Professional Geologist 5551 Geotechnical Engineer 2346 Certified Engineering Geologist 1760 (expires 03/31/08) (expires 12/31/07) Attachments: Location Map Figure 1 Plot Plan Figure 2 Boring Logs Figures 3 and 4 Laboratory Test Results Figures 5 Distribution: Addressee (3) REFERENCES 1. Abbott, P., L., edited, "On the Manner of Deposition of the Eocene Strata in Northern San Diego County", San Diego Association of Geologists, Guidebook April 13, 1985. 2. Aerial Photographs, Flight GS-VBTA, Photos 1-174 and 1-175, dated May 8, 1967. 3. Cao, Tianqing, et al, "The Revised 2002 California Probabilistic Seismic Hazard Maps,"dated June 2003. 4. Chereskin Architecture, "Haggbloom/Page Residence Site and Architectual Plans", dated October 26, 2005. 5. Encinitas Ortho and Topo Map, Flight Date July 2001, Map Coordinates Stateplate NAD83 Feet, CA Zone 6, 1-inch equals 20-feet. 6. ICBO, "California Building Code,"2001 Edition. 7. ICBO, "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada", dated February 1998. 8. Jennings, Charles W., "Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Map No. 6", 1994. 9. Kern, Philip and Rockwell, Thomas, K., "Chronology and Deformation of Quaternary Marine Shorelines, San Diego County, California", South Coast Geological Society, Inc., Annual Field Trip Guide Book No. 20, 1992. 10. Peterson, M., Beeby, W., Bryant, W., et al., "Seismic Shaking Hazard Maps of California, California Division of Mines and Geology, Map Sheet 48", 1999. 11. "Probabilistic Seismic Hazard Assessment for the State of California",DMG Open-File Report 96-08 and USGS Open-File Report 96-706, 1996. 12. Tan, Siang S. and Giffen, Desmond G., "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California," Landslide Hazard Identification Map No. 35, California Division of Mines and Geology, 1995. 13. Tan, Siang S. and Kennedy, Michael P., "Geologic Maps of the Northwestern Part of San Diego County, California, Plate 1", California Division of Mines and Geology, Open-File Report 96-02, 1996. Project No.5429.1 Log No.9937 REFERENCES 14. Treiman, Jerome A., "The Rose Canyon Fault Zone, Southern California", California Division of Mines and Geology, Open-File Report 93-02. 15. Weber, Harold F., Jr., "Recent Slope Failures, Ancient Landslides and Related Geology of the North-Central Coastal Area, San Diego County, California", California Divisions of Mines and Geology, Open-File Report 82-12L, 1982. Project No.5429.1 Log No.9937 d f0 LL P 0 N C ui Lli 2 Z U Wa4 4 " p z r ZO F V W G, „ 1 i t S j „.N r a Q � I 6 /7 1 C7 w i. �.cn r2 i z [ —_ Z W a U p W �y X 1 I O CL CL 2 €fCtEf I i DRILLING COMPANY:HEI RIG: Hand Auger DATE: 02/15/06 BORING DIAMETER: 6" DRIVE WEIGHT: DROP: W a as F H °° M - W a E o H M w x a o cn w x w z U U SOIL DESCRIPTION EF W (0 C) E W o 0 0 BORING NO. HA-'I ELEVATION: 126 t W Q W Q U ul 0.0 SM FILL: Dark brown, silty to clayey fine to medium sand,very SC moist, loose TERRACE DEPOSITS: Red brown, silty fine to medium sand, moist, medium dense -x 110 9.7 109 11.4 5.0 @ 5': Becomes yellow orange,silty fine to medium sand, moise, dense 110 11.9 Total depth 7 feet No water No caving 10.0 BORING NO. HA-2 ELEVATION: 112 t 0.0 SM FILL: Brown silty fine to medium sand, damp, loose -x @ 1.5': Becomes brown, gravelly to silty fine to medium sand, damp, loose 5.0 Total depth 4 feet(refusal on roots) No water Minor caving or gravelly soils 10.0 BORING LOG 430 Andrew Avenue HETHERINGTON ENGINEERING, INC. Encinitas, California GEOTECHNICAL CONSULTANTS PROJECT NO. 5429.1 FIGURE NO. 3 DRILLING COMPANY:HEI RIG: Hand Auger DATE: 02/15/06 BORING DIAMETER: 6" DRIVE WEIGHT: DROP: W a w E E W a o U w x m "' w D z U U SOIL DESCRIPTION E W cn 0 E W o a °am q a 0 o o n BORING NO. HA-3 ELEVATION: 108 t 0.0 SM FILL: Dark brown to brown, silty fine to medium sand, damp, -X loose TERRACE DEPOSITS: (Weathered) Red brown, silty fine to medium sand, damp, loose to medium dense, some pinholes 101 3.9 -X @ T: Becomes less weathered, no pinholes 100 2.9 @ 4': Becomes yellow orange 5.0 @ 5': Becomes red orange and dense 107 8.9 Total depth 8 feet No water No caving 10.0 BORING LOG 430 Andrew Avenue HETHERINGTON ENGINEERING, INC. Encinitas, California GEOTECHNICAL CONSULTANTS PROJECT NO. 55429.1 FIGURE NO. 4 LABORATORY RESULTS M". SULFATE;TE ST;RE SULTS (EPA`9038). Sam le Location : Soluble Sulfate in Sail % HA-1 3'-6' 1.32 HA-342'-4' 0.0216 EXPANSION INDEX (ASTM•D'4829) Sample Initial Compacted Final Expansion Expansion Location Moisture, Dry Moisture Index Potential (a/e) Density M, C HA-3(&,2'-4' 1 7.5 113 15.2 0 Very low MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT DETERMINATION,-, (ASTM:D 1557-02A) Sample, Description Maximum Dry Optimum Moisture_ Location - Density c Content °f HA-1 @3'-6' Light brown, fine to 124.0 7.5 medium sand DIRECT SHEAR (ASTM D 3080) Sample Angle of Internal Cohesion(psf) Remarks Location Friction ° HA-1 @ 3'-6' 32 125 Remolded to 90%@ opt.,soaked, consolidated and drained Figure 5 Project No.5429.1 Log No.9937 PASCO ENGINEERING, INC. W R.C.E. 9577C0 JOSEPH YUHAS 535 NORTH HIGHWAY 101, SUITE A P.L.S.5211 SOLANA BEACH, CA 92075 W.JUSTIN SUITER (858) 259-8212 R.C.E.68964 FAX (858) 259-4812 September 6, 2006 PE 1498 Candy Haggblom 430 Andrew Avenue Encinitas, CA 92024 RE: DRAINAGE AT GARAGE ENTRANCE Dear Ms. Haggblom, At the request of the City of Encinitas we have prepared this letter to inform you of the potential for storm water runoff to enter the garage near the southwest corner. Because of the severity of the slope in the private road and the proximity of the garage to the edge of pavement it is not possible for the garage to be located entirely above the existing flowline of the road. Therefore, in a heavy storm there will be drainage that does not continue along Andrew Avenue but instead flows east toward the garage. It is the professional opinion of Pasco Engineering that if properly maintained, the 12" trench drain will prevent significant amounts of drainage from entering the garage. Should small amounts of drainage bypass the trench drain it is our opinion that the internal slope of the garage (2% out) will adequately convey the water back to the trench drain. Please do not hesitate to call if you have questions. Sincerely, � 1�k W. Jultin Suiter,RCE 68964 Vice President-Engineering , I u SEP t } 2006 ,s