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Home My WebLink AboutCT 2018-0001; WALNUT BEACH HOMES; FINAL - REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION; 2018-11-14REPORT OF PRELIMINARY GEOTECHNICALINVESTIGATION Proposed Walnut Avenue Residential Project 362 Walnut Avenue Carlsbad, California JOB NO. 17-11664 14 November 2017 Prepared for: Rincon Real Estate Group, Inc. RECORD COPY �-JnjtiaJ ��fD LAND DEVELOPMENT Er GINEERING g/r/r, . r• Date FINAL -~~, Geotechnical Exploration, Inc. SOIL AND FOUNDATION ENGINEERING • GROUNDWATER • ENGINEERING GEOLOGY 14 November 2017 Rincon Real Estate Group, Inc. 3005 S .. El Camino Real San Clemente, CA 92672 Attn: Mr. Kevin Dunn Job No. 17-11664 Subject: Report of Preliminary Geotechnical Investigation Proposed Walnut Avenue Residential Project 362 Walnut Avenue Carlsbad, California Dear Mr. Dunn: In accordance with your request, and our proposal of October 11, 2017, Geotechnical Exploration, Inc. has performed a preliminary geotechnical investigatio'n and infiltration testing for the subject property. The field work was performed on October 16, 2017. In our opinion, if the conclusions and recommendations presented in this report are implemented during site preparation and construction, the site will be suited for the proposed residential project and associated improvements. This opportunity to be of service is sincerely appreciated. Should you have any questions concerning the following report, please do not hesitate to contact us. Reference to our Job No. 17-11664 will expedite a response to your inquiries. Respectfully submitted, GEOTECHNICAL EXPLORATION, INC. R.C.E. 34422/G.E. 2007 Senior Geotechnical Engineer 7420 lRADE STREET$ SAN DIEGO, CA. 92121 • (858) 549-7222 e FAX: (858) 549-1604 • EMAIL: geotech@gel-sd.com I. II. III. IV. V. VI. VII. VIII. IX. X. XI. XII. PROJECT SUMMARY SCOPE OF WORK SITE DESCRIPTION FIELD INVESTIGATION TABLE OF CONTENTS LABORATORY TESTS & SOIL INFORMATION REGIONAL GEOLOGIC DESCRIPTION SITE-SPECIFIC SOIL & GEOLOGIC DESCRIPTION GEOLOGIC HAZARDS GROUNDWATER CONCLUSIONS AND RECOMMENDATIONS GRADING NOTES LIMITATIONS REFERENCES FIGURES I. II. IIIa-e. IV. V. Vicinity Map Plot Plan Exploratory Excavation Logs Laboratory Test Results Geologic Map and Legend APPENDICES A. Unified Soll Classification System B. Infiltration Test Data and Infiltration Rate Calculations C. USDA Web Soil Survey Map D. USGS Design Maps Summary Report 1 1 2 2 5 7 11 12 20 22 38 39 REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Walnut Avenue Residential Project 362 Walnut Avenue Carlsbad, California JOB NO. 17-11664 The following report presents the findings and recommendations of Geotechnical Exploration, Inc. for the subject project. I. PROJECT SUMMARY It is our understanding, based on communications with you, that the existing single-story, single-family residential structures will be removed, and the site will be developed to receive 6 two-unit residential structures with attached garages and associated improvements. The proposed residential structures are to be constructed of standard-type building materials utilizing a conventional foundation system. Final construction plans have not been provided to us during the preparation of this report, however, when completed they should be made available for our review. Additional or modified recommendations will be provided at that time if warranted. II. SCOPE OF WORK The scope of work performed for this investigation included a site reconnaissance and subsurface exploration program, laboratory testing, geotechnical engineering analysis of the field and laboratory data, infiltration testing, and the preparation of this report. The data obtained and the analyses performed were for the purpose of providing design and construction criteria for the project earthwork, building foundations, and slab on-grade floors. Proposed Walnut Avenue Residence Project Carlsbad, California III. SITE DESCRIPTION Job No. 17-11664 Page 2 The property is known as Assessor's Parcel No. 204-132-17-00, Parcel 2, per Recorded Map PM 00425, in the City of Carlsbad, County of San Diego, State of California. Refer to Figure No. I, the Vicinity Map, for the site location. The site, more particularly referred to as 362 Walnut Avenue, consists of approximately 0.57-acre. The lot is located on the north side of Walnut Avenue, in the City of Carlsbad. The property is bordered on the north, at approximately the same elevation, by a multi-family residential property; on the east, at slightly lower elevation , by a multi-family residential property; on the west, at slightly lower elevation by a multi-family residential property; and to the south at slightly lower elevation by Walnut Avenue. In general, the lot slopes very gently to the southwest and northeast. For Plot Plan, refer to Figure No. II. The existing structures on the property consist of two single-story single-family residences and associated improvements. Vegetation consists of ornamental landscaping including mature trees, lawn and decorative shrubbery. The building pad is relatively level at an approximate elevation of 55 feet above mean sea level (MSL). Elevations across the property range from approximately 52 feet above (MSL) in the southwest corner of the property to approximately 56 feet above (MSL) in the northwest corner of the property. IV. FIELD INVESTIGATION The field investigation consisted of a surface reconnaissance and a subsurface exploration program utilizing hand tools to investigate and sample the subsurface Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 3 soils. Five exploratory excavations were advanced across the lot in the vicinity of the proposed structures. The exploratory excavations were advanced to a maximum depth of 3 feet, in order to obtain representative soil samples and to define the soil profile across the project area. The soils encountered in the exploratory excavations were continuously logged in the field by our geologist and described in accordance with the Unified Soil Classification System (refer to Appendix A). The approximate locations of the exploratory excavations are shown on the Plot Plan, Figure No. II. Representative samples were obtained from the exploratory excavations at selected depths appropriate to the investigation. All samples were returned to our laboratory for evaluation and testing. Exploratory excavation logs were prepared on the basis of our observations and laboratory test results. Logs of the exploratory excavations are attached as Figure Nos. Illa-e. A. Infiltration Testing We performed simple open pit falling head testing at two locations in the northeast corner of the property at a depth of 36 inches at INF-1, and 36.5 inches at INF-2 per the requirements of the City of Carlsbad Storm Water Standards, BMP Design Manual, in accordance with Appendix D. Testing at the two locations (INF-1 and INF-2), revealed falling head rates of 10.000 and 9.231 minutes/inch, respectively. The simple open pit falling head test rate results for INF-1 and INF-2 have been converted to infiltration rates, using the Porchet Method and indicate infiltration rates of 4.000-and 4.216-inch/hour, respectively. Refer to Appendix B for simple open pit test rate results and simple open pit to infiltration rate calculations. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 4 Formational materials referred to as Quaternary-age Old Paralic deposits (QoP6-1) were encountered underlying the thin veneer of topsoil and fill' soils in both exploratory infiltration excavations. Laboratory test results at infiltration test location INF-1 and INF-2, indicate 16% and 19% of the soils passed the #200 sieve, respectively. Based on our review of USDA Web Soil Survey map, the site has been assigned to hydrologic soil group (HSG) B. Refer to Appendix C for USDA Web Soil Survey Map. As part of our geologic/geotechnical site evaluation, we considered the following issues: 1. The site is not subject to high groundwater conditions (within 10 feet of the base of the infiltration facility. 2. The site is not in relatively close proximity to a known contaminated soil site. 3. Portions of the site are underlain by artificial fill soils over medium dense silty sand formational soils, but not subject to hydroconsolidation. 4 . The proposed bio-retention basin has infiltration rates between of 4.000-and 4.216-inch/hour without an applied factor of safety. 5. Portions of the site may have a silt plus clay percentage of greater than 50. 6. The proposed bio-retention basin is not underlain at relatively shallow depths by practically impermeable formational soils. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 5 7. The proposed bio-retention basin is not located within 100 feet from a known drinking water well. 8. The proposed bio-retention basin is not located within 100 feet from an on- site septic system or designated expansion area. 9. The proposed bio-retention basin is not located adjacent to a slope steeper than 25 percent. Based on the results of our simple open pit falling head testing and evaluation of the infiltration rates, it is our professional opinion that the proposed bio-retention basin has favorable soil conditions and appreciable infiltration rates for the design of full infiltration BMPs. However, we recommend the sidewalls of the proposed basin be lined and the basin be located at least 5 feet away from any proposed structures, retaining walls and utility trenches. V. LABORATORY TESTS & SOIL INFORMATION Laboratory tests were performed on the retrieved soil samples in order to evaluate their index, strength, expansion, and compressibility properties. The test results are presented on Figures Nos. IIla-e and IV. The following tests were conducted on representative soil samples: 1. Moisture Content (ASTM D2216-10) 2. Determination of Percentage of Particles Smaller than #200 Sieve (ASTM D1140-14) 3. Laboratory Compaction Characteristics (ASTM 01557-12) 4. Density Measurements (ASTM 0 2937) Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 6 Moisture content measurements were performed to establish the in situ moisture of samples retrieved from the exploratory excavations. Moisture content and density measurements were performed by ASTM methods D2216 and D2937. These density tests help to establish the in situ moisture and density of samples retrieved from the exploratory excavations. The particle size smaller than a No. 200 sieve analysis (ASTM D1140-06) tests (ASTM D4318-05) aid in classifying the tested soils in accordance with the Unified Soil Classification System and provide qualitative information related to engineering characteristics such as expansion potential, permeability, and shear strength. Laboratory compaction tests (ASTM D1557-12) establish the laboratory maximum dry density and optimum moisture content of the tested soils and are also used to aid in evaluating the strength characteristics of the soils. The expansion potential of soils is determined, when necessary, utilizing the Standard Test Method for Expansion Index of Soils (ASTM D4829). In accordance with the same Standard (Table 5.3), potentially expansive soils are classified as follows: EXPANSION I NDEX POTENTIAL EXPANSI ON Oto 20 Very low 21 to 50 Low 51 to 90 Medium 91 to 130 Hiqh Above 130 Very hiqh Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 7 Based on the particle size test results and our experience with the encountered soils, it is our opinion that the on-site fill and formational soils in general possess a low expansion potential. VI. REGIONAL GEOLOGIC DESCRIPTION San Diego County has been divided into three major geomorphic provinces: the Coastal Plain, the Peninsular Ranges and the Salton Trough. The Coastal Plain exists west of the Peninsular Ranges. The Salton Trough is east of the Peninsular Ranges. These divisions are the result of the basic geologic distinctions between the areas. Mesozoic metavolcanic, metasedimentary and plutonic rocks predominate in the Peninsular Ranges with primarily Cenozoic sedimentary rocks to the west and east of this central mountain range (Demere, 1997). In the Coastal Plain region, where the subject property is located, the "basement" consists of Mesozoic crystalline rocks. Basement rocks are also exposed as high relief areas (e.g., Black Mountain northeast of the subject property and Cowles Mountain near the San Carlos area of San Diego). Younger Cretaceous and Tertiary sediments lap up against these older features. These sediments form a "layer cake" sequence of marine and non-marine sedimentary rock units, with some formations up to 140 million years old. Faulting related to the La Nacion and Rose Canyon Fault zones has broken up this sequence into a number of distinct fault blocks in the southwestern part of the county. Northwestern portions of the county are relatively undeformed by faulting (Demere, 1997). The Peninsular Ranges form the granitic spine of San Diego County. These rocks are primarily plutonic, forming at depth beneath the earth's crust 140 to 90 million years ago as the result of the subduction of an oceanic crustal plate beneath the Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 8 North American continent. These rocks formed the much larger Southern California batholith. Metamorphism associated with the intrusion of these great granitic masses affected the much older sediments that existed near the surface over that period of time. These metasedimentary rocks remain as roof pendants of marble, schist, slate, quartzite and gneiss throughout the Peninsular Ranges. Locally, Miocene-age volcanic rocks and flows have also accumulated within these mountains (e.g., Jacumba Valley). Regional tectonic forces and erosion over time have uplifted and unroofed these granitic rocks to expose them at the surface (Demere, 1997). The Salton Trough is the northerly extension of the Gulf of California. This zone is undergoing active deformation related to faulting along the Elsinore and San Jacinto Fault Zones, which are part of the major regional tectonic feature in the southwestern portion of California, the San Andreas Fault Zone. Translational movement along these fault zones has resulted in crustal rifting and subsidence. The Salton Trough, also referred to as the Colorado Desert, has been filled with sediments to depth of approximately 5 miles since the movement began in the early Miocene, 24 million years ago. The source of these sediments has been the local mountains as well as the ancestral and modern Colorado River (Demere, 1997). As indicated previously, the San Diego area is part of a seismically active region of California. It is on the eastern boundary of the Southern California Continental Borderland, part of the Peninsular Ranges Geomorphic Province. This region is part of a broad tectonic boundary between the North American and Pacific Plates. The actual plate boundary is characterized by a complex system of active, major, right- lateral strike-slip faults, trending northwest/southeast. This fault system extends eastward to the San Andreas Fault (approximately 70 miles from San Diego) and Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 9 westward to the San Clemente Fault (approximately 50 miles off-shore from San Diego) (Berger and Schug, 1991). In California, major earthquakes can generally be correlated with movement on active faults. As defined by the California Division of Mines and Geology (Hart, E.W., 1980), an "active" fault is one that has had ground surface displacement within Holocene time (about the last 11,000 years). Additionally, faults along which major historical earthquakes have occurred (about the last 210 years in California) are also considered to be active (Association of Engineering Geologist, 1973). The California Division of Mines and Geology (now the California Geological Survey) defines a "potentially active" fault as one that has had ground surface displacement during Quaternary time, that is, between 11,000 and 1.6 million years (Hart, E.W., 1980). During recent history, prior to Apri l 2010, the San Diego County area has been relatively quiet seismically. No fault ruptures or major earthquakes had been experienced in historic time within the greater San Diego area. Since earthquakes have been recorded by instruments (since the 1930s), the San Diego area has experienced scattered seismic events with Richter magnitudes generally less than M4.0. During June 1985, a series of small earthquakes occurred beneath San Diego Bay, three of which were recorded at M4.0 to M4.2. In addition, the Oceanside earthquake of July 13, 1986, located approximately 26 miles offshore of the City of Oceanside, had a magnitude of MS.3 (Hauksson and Jones, 1988). On June 15, 2004, a M5.3 earthquake occurred approximately 45 miles southwest of downtown San Diego (26 miles west of Rosarito, Mexico). Although this earthquake was widely felt, no significant damage was reported. Another widely felt Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 10 earthquake on a distant southern California fault was a MS.4 event that took place on July 29, 2008, west-southwest of the Chino Hills area of Riverside County. Several earthquakes ranging from MS.0 to M6.0 occurred in northern Baja California, centered in the Gulf of California on August 3, 2009. These were felt in San Diego but no injuries or damage was reported. A MS.8 earthquake followed by a M4.9 aftershock occurred on December 30, 2009, centered about 20 miles south of the Mexican border city of Mexicali. These were also felt in San Diego, swaying high-rise buildings, but again no significant damage or injuries were reported. On Easter Sunday April 4, 2010, a large earthquake occurred in Baja California, Mexico. It was widely felt throughout the southwest including Phoenix, Arizona and San Diego in California. This M7.2 event, the Sierra El Mayor earthquake, occurred in northern Baja California, approximately 40 miles south of the Mexico-USA border at shallow depth along the principal plate boundary between the North American and Pacific plates. According to the U. S. Geologica l Survey this is an area with a high level of historical seismicity, and it has recently also been seismically active, though this is the largest event to strike in this area since 1892. The April 4, 2010, earthquake appears to have been larger t han the M6 .9 earthquake in 1940 or any of the early 20th century events (e.g., 1915 and 1934) in this region of northern Baja California. The event caused widespread damage to structures, closure of businesses, government offices and schools, power outages, displacement of people from their homes and injuries in the nearby major metropolitan areas of Mexicali in Mexico and Calexico in Southern California. This event's aftershock zone extends significantly to the northwest, overlapping with the portion of the fault system that is thought to have ruptured in 1892. Some structures in the San Diego area experienced minor damage and there were Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 11 some injuries. Ground motions for the April 4, 2010, main event, recorded at stations in San Diego and reported by the California Strong Motion Instrumentation Program (CSMIP), ranged up to 0.058g. Aftershocks from this event continue to the date of this report along the trend northwest and south of the original event, including within San Diego County, closer to the San Diego metropolitan area. There have been hundreds of these earthquakes including events up to MS. 7. On July 7, 2010, a MS.4 earthquake occurred in Southern California at 4:53 pm (Pacific Time) about 30 miles south of Palm Springs, 25 miles southwest of Indio, and 13 miles north-northwest of Borrego Springs. The earthquake occurred near the Coyote Creek segment of the San Jacinto Fault. The earthquake exhibited right lateral slip to the northwest, consistent with the direction of movement on the San Jacinto Fault. The earthquake was felt throughout Southern California, with strong shaking near the epicenter. It was followed by more than 60 aftershocks of Ml.3 and greater during the first hour. Seismologists expect continued aftershock activity. In the last 50 years, there have been four other earthquakes in the magnitude MS.0 range within 20 kilometers of the Coyote Creek segment: MS.8 in 1968, MS.3 on 2/25/1980, MS.0 on 10/31/2001, and MS .2 on 6/12/2005. The biggest earthquake near this location was the M6.0 Buck Ridge earthquake on 3/25/1937. VII. SITE-SPECIFIC SOIL & GEOLOGIC DESCRIPTION Our field work, reconnaissance and review of the geologic map by Kennedy and Tan, 2007, "Geologic Map of Oceanside, 30'x60' Quadrangle, CA," indicate that the site is underlain by Quaternary-age Old Paralic Deposits (Qop6.7) formational materials. The formational soils are overlain by approximately 0.25 to 1 feet of Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 12 topsoil and fill soils across the lot (Refer to the Excavation Logs, Figure Nos. IIIa-e). Figure No. V presents a plan view geologic map (Kennedy and Tan, 2007) of the general area of the site. Fill and Topsoils (Qaf): The lot is overlain by approximately 0.25 to 0 .5 feet of topsoils as encountered in all of the exploratory excavations with the exception of exploratory excavation HP-4. Fill soils were encountered in exploratory excavation HP-4 to a depth of approximately 1 foot. The encountered fill and topsoils generally consists of loose to medium dense, dry to slightly moist, brown to reddish brown silty sand and are considered to have a low expansion potential. Refer to Figure No. III. Old Paralic Deposits (Qopul;_ The encountered formational materials consist primarily of medium dense, slightly moist, reddish brown to dark reddish brown, si lty sand. The formational soils were encountered at a depth of approximately 0.25 to 1 feet in all exploratory excavations. The formational soils are considered to have a low expansion potential. Refer to Figure No. III. VIII. GEOLOGIC HAZARDS The following is a discussion of the geologic conditions and hazards common to this area of the City of Carlsbad, as well as project-specific geologic information relating to development of the subject property. Proposed Walnut Avenue Residence Project Carlsbad, California A. Local and Regional Faults Job No. 17-11664 Page 13 Reference to the geologic map of the area (Kennedy and Tan, 2007), Figure No. V, indicates that no faults are shown to cross the site. In our explicit professional opinion, neither an active fault nor a potentially active fault underlies the site. Rose Canyon Fault: The Rose Canyon Fault Zone (Mount Soledad and Rose Canyon Faults) is located approximately 5 miles southwest of the subject site. The Rose Canyon Fault is mapped trending north-south from Oceanside to downtown San Diego, from where it appears to head southward into San Diego Bay, through Coronado and offshore. The Rose Canyon Fault Zone is considered to be a complex zone of onshore and offshore, en echelon strike slip, oblique reverse, and oblique normal faults. The Rose Canyon Fault is considered to be capable of generating an M7.2 earthquake and is considered microseismically active, although no significant recent earthquakes are known to have occurred on the fault. Investigative work on faults that are part of the Rose Canyon Fault Zone at the Pol ice Administration and Technical Center in downtown San Diego, at the SDG&E facility in Rose Canyon, and within San Diego Bay and elsewhere within downtown San Diego, has encountered offsets in Holocene (geologically recent) sediments. These findings confirm Holocene displacement on the Rose Canyon Fault, which was designated an "active" fault in November 1991 (Hart, E.W. and W .A. Bryant, 2007, Fault-Rupture Hazard Zones in California, Cal ifornia Geological Survey Special Publication 42). Coronado Bank Fault: The Coronado Bank Fault is located approximately 21 miles southwest of the site. Evidence for this fault is based upon geophysical data (acoustic profiles) and the general alignment of epicenters of recorded seismic Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 14 activity (Greene, 1979). The Oceanside earthquake of M5.3 recorded July 13, 1986, is known to have been centered on the fault or within t he Coronado Bank Fault Zone. Although this fault is considered active, due to the seismicity within the fault zone, it is significantly less active seismically than the Elsinore Fault (Hileman, 1973). It is postulated that the Coronado Ba nk Fault is capable of generating a M7.6 earthquake and is of great interest due to its close proximity to the greater San Diego metropolitan area. Newport-Inglewood Fault: The Newport-Inglewood Fault Zone is located approximately 5 miles northwest of the site. A significant earthquake (M6.4) occurred along this fault on March 10, 1933. Since then no additional significant events have occurred. The fault is believed to have a slip rate of approximately 0.6 mm/yr with an unknown recurrence interval. This fault is believed capable of producing an earthquake of M6.0 to M7.4 (SCEC, 2004). Elsinore Fault: The Elsinore Fault is located approximately 25 miles northeast of the site. The fault extends approximately 200 kilometers (125 miles) from the Mexican border to the northern end of the Santa Ana Mountains. The Elsinore Fault zone is a 1-to 4-mile-wide, northwest-southeast-trending zone of discontinuous and en echelon faults extending through portions of Orange, Riverside, San Diego, and Imperial Counties. Individual faults within the Elsinore Fault Zone range from less than 1 mile to 16 miles in length. The trend, length and geomorphic expression of the Elsinore Fault Zone identify it as being a part of the highly active San Andreas Fault system. Like the other faults in the San Andreas system, the Elsinore Fau lt is a transverse fault showing predominantly right-lateral movement. According to Hart, et al. (1979), this movement averages less than 1 centimeter per year. Along most of its Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 15 length, the Elsinore Fault Zone is marked by a bold topographic expression consisting of linearly aligned ridges, swales and hallows. Faulted Holocene alluvial deposits (believed to be less than 11,000 years old) found along several segments of the fault zone suggest that at least part of the zone is currently active. Although the Elsinore Fault Zone belongs to the San Andreas set of active, northwest-trending, right-slip faults in the southern California area (Crowell, 1962), it has not been the site of a major earthquake in historic time, other than a M6.0 earthquake near the town of Elsinore in 1910 (Richter, 1958; Toppozada and Parke, 1982). However, based on length and evidence of late-Pleistocene or Holocene displacement, Greensfelder (1974) has estimated that the Elsinore Fault Zone is reasonably capable of generating an earthquake ranging from M6.8 to M7.1. Faulting evidence exposed in trenches placed in Glen Ivy Marsh across the Glen Ivy North Fault (a strand of the Elsinore Fault Zone between Corona and Lake Elsinore), suggest a maximum earthquake recurrence interval of 300 years, and when combined with previous estimates of the long-term horizontal slip rate of 0 .8 to 7 .0 mm/year, suggest t ypical earthquakes of M6.0 to M7.0 (Rockwell, 1985). San Jacinto Fault: The San Jacinto Fault is located 47 miles to the northeast of the site. The San Jacinto Fault Zone consists of a series of closely spaced fault s, including the Coyote Creek Fault, that form the western margin of the San Jacinto Mountains. The fault zone extends from its junction with the San Andreas Fault in San Bernardino, southeasterly toward t he Brawley area, where it continues south of the international border as the Imperial Transform Fault (Earth Consultants International [ECI ], 2009). Proposed Walnut Avenue Residence Project Carlsbad, California Job No . 17-11664 Page 16 The San Jacinto Fault zone has a high level of historical seismic activity, with at least 10 damaging earthquakes (M6.0 to M7.0) having occurred on this fault zone between 1890 and 1986. Earthquakes on the San Jacinto Fault in 1899 and 1918 caused fatalities in the Riverside County area. Offset across this fault is predominantly right-lateral, similar to the San Andreas Fault, although some investigators have suggested that dip-slip motion contributes up to 10% of the net slip (ECI, 2009). The segments of the San Jacinto Fault that are of most concern to major metropolitan areas are the San Bernardino, San Jacinto Valley and Anza segments. Fault slip rates on the various segments of the San Jacinto are less well constrained than for the San Andreas Fault, but the available data suggest slip rates of 12 ±6 mm/yr for the northern segments of the fault, and slip rates of 4 ±2 mm/yr for the southern segments. For large ground-rupturing earthquakes on the San Jacinto fault, various investigators have suggested a recurrence interval of 150 to 300 years. The Working Group on California Earthquake Probabilities (WGCEP, 2008) has estimated that there is a 31 percent probability that an earthquake of M6. 7 or greater will occur within 30 years on this fault. Maximum credible earthquakes of M6.7, M6.9, and M7.2 are expected on the San Bernardino, San Jacinto Valley and Anza segments, respectively, capable of generating peak horizontal ground accelerations of 0.48g to 0.53g in the County of Riverside, (ECI, 2009). A MS.4 earthquake occurred on the San Jacinto Fault on July 7, 2010. The United States Geological Survey has issued the following statements with respect to the recent seismic activity on southern California faults : The San Jacinto fault, along with the Elsinore, San Andreas, and other faults, is part of the plate boundary that accommodates about 2 inches/year of motion as the Pacific plate moves northwest relative to Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 17 the North American plate. The largest recent earthquake on the San Jacinto fault, near this location, the M6.5 1968 Borrego Mountain earthquake April 8, 1968, occurred about 25 miles southeast of the July 7, 2010, M5.4 earthquake. This MS.4 earthquake follows the 4th of April 2010, Easter Sunday, M7.2 earthquake, located about 125 miles to the south, well south of the US Mexico international border. A M4.9 earthquake occurred in the same area on June 12th at 8:08 pm (Pacific Time). Thus this section of the San Jacinto fault remains active. Seismologists are watching two major earthquake faults in southern California. The San Jacinto fault, the most active earthquake fault in southern California, extends for more than 100 miles from the international border into San Bernardino and Riverside, a major metropolitan area often called the Inland Empire. The Elsinore fault is more than 110 miles long, and extends into the Orange County and Los Angeles area as the Whittier fault. The Elsinore fault is capable of a major earthquake that would significantly affect the large metropolitan areas of southern California. The Elsinore fault has not hosted a major earthquake in more than 100 years. The occurrence of these earthquakes along the San Jacinto fault and continued aftershocks demonstrates that the earthquake activity in the region remains at an elevated level. The San Jacinto fault is known as the most active earthquake fault in southern California. Caltech and USGS seismologist continue to monitor the ongoing earthquake activity using the Caltech/USGS Southern California Seismic Network and a GPS network of more than 100 stations. B. Other Geologic Hazards Ground Rupture: Ground rupture is characterized by bedrock slippage along an established fault and may result in displacement of the ground surface. For ground rupture to occur along a fault, an earthquake usually exceeds M5.0. If a MS.0 earthquake were to take place on a local fault, an estimated surface-rupture length 1 mile long could be expected (Greensfelder, 1974). Our investigation indicates Proposed Walnut Avenue Residence Project Carlsbad, California Job No . 17-11664 Page 18 that the subject site is not directly on a known active fault trace and, therefore, the risk of ground rupture is remote. Liquefaction: The liquefaction of saturated sands during earthquakes can be a major cause of damage to buildings. Liquefaction is the process by which soils are transformed into a viscous fluid that will flow as a liquid when unconfined. It occurs primarily in loose, saturated sands and silts when they are sufficiently shaken by an earthqua ke. On this site, the risk of liquefaction of foundation materials due to seismic shaking is considered to be low due to the medium dense to dense nature of the natural-ground material and the lack of a shallow static groundwater surface under the site. In our opinion, the site does not have a potential for soil strength loss to occur due to a seismic event. Tsunami: A tsunami is a series of long waves generated in the ocean by a sudden displacement of a large volume of water. Underwater earthquakes, landslides, volcanic eruptions, meteoric impacts, or onshore slope failures can cause this displacement. Tsunami waves can travel at speeds averaging 450 to 600 miles per hour. As a tsunami nears the coastline, its speed diminishes, its wave length decreases, and its height increases greatly. After a major earthquake or other near-shore tsunami-inducing activity occurs, a tsunami could reach t he shore within a few minutes. One coastal community may experience no damaging waves while another may experience very destructive waves. Some low-lying areas could experience severe inland inundation of water and deposition of debris. Wave heights and run-up elevations from tsunami along the San Diego Coast have historically fallen within the normal range of the tides (Joy 1968). The largest tsunami effect recorded in San Diego since 1950 was May 22, 1960, which had a maximum wave height of 2.1 feet (NOAA, 1993). In this event, 80 meters of dock Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 19 were destroyed and a barge sunk in Quivera Basin. Other tsunamis felt in San Diego County occurred on November 5, 1952, with a wave height of 2.3 feet caused by an earthquake in Kamchatka; March 9, 1957, with a wave height of 1.5 feet; May 22, 1960, at 2.1 feet; March 27, 1964, with a wave height of 3. 7 feet and September 29, 2009, with a wave height of 0.5 feet. It should be noted that damage does not necessarily occur in direct relationship to wave height, illustrated by the fact that the damage caused by the 2.1-foot wave height in 1960 was worse than damage caused by several other tsunamis with higher wave heights. Historical wave heights and run-up elevations from tsunamis that have impacted the San Diego Coast have historically fallen within the normal range of the tides (Joy, 1968). The risk of a tsunami affecting the site is considered moderate as the site is situated at an elevation of approximately 55 feet above mean sea level and approximately 1000 feet to an exposed beach. The site is not mapped within a possible inundation zone on the California Geological Survey's 2009 "Tsunami Inundation Map for Emergency Planning, Oceanside Quadrangle, San Diego County." Geologic Hazards Summary: It is our opinion, based upon a review of the available maps, our research and our site investigation, that the site is underlain by relatively stable formational materials and is suited for the for the proposed residential project and associated improvements provided the recommendations herein are implemented. No significant geologic hazards are known to exist on the site that would prevent the proposed construction . Ground shaking from earthquakes on active southern California faults and active faults in northwestern Mexico is the greatest geologic hazard at the property. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 20 In our explicit professional opinion, no "active" or "potentially active" faults underlie the project site. IX. GROUNDWATER No groundwater was encountered during the course of our field investigation and we do not anticipate significant groundwater problems to develop in the future, if the property is developed as proposed and proper drainage is implemented and maintained. The true groundwater surface is assumed to be at a depth of over 50 feet below the existing and planned building pads. Based on exploratory drilling throughout San Diego County, we would expect minor seeps between the ground surface and true water table due to transient "perching" of vadose water on exceptionally dense, low permeability beds within the formational materials. It should be kept in mind that any required construction operations will change surface drainage patterns and/or reduce permeabilities due to the densification of compacted soils. Such changes of surface and subsurface hydrologic conditions, plus irrigation of landscaping or significant increases in rainfall, may result in the appearance of surface or near-surface water at locations where none existed previously. The damage from such water is expected to be localized and cosmetic in nature, if good positive drainage is implemented, as recommended in this report, during and at the completion of construction. On properties such as the subject site where dense, low permeability soils exist at shallow depths, even normal landscape irrigation practices on the property or neighboring properties, or periods of extended rainfall, can result in shallow "perched" water conditions. The perching (shallow depth) accumulation of water on a low permeability surface can result in areas of persistent wetting and drowning of Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 21 lawns, plants and trees. Resolution of such conditions, should they occur, may require site-specific design and construction of subdrain and shallow "wick" drain dewatering systems. Subsurface drainage with a properly designed and constructed subdrain system will be required along with continuous back drainage behind any proposed lower-level basement walls, property line retaining walls, or any perimeter stem walls for raised-wood floors where the outside grades are higher than the crawl space grades. Furthermore, crawl spaces, if used, should be provided with the proper cross-ventilation to help reduce the potential for moisture-related problems. Additional recommendations may be required at the time of construction. It must be understood that unless discovered during site exploration or encountered during site construction operations, it is extremely difficult to predict if or where perched or true groundwater conditions may appear in the future. When site fill or formational soils are fine-grained and of low permeability, water problems may not become apparent for extended periods of time. Water conditions, where suspected or encountered during construction, should be evaluated and remedied by the project civil and geotechnical consultants. The project developer and property owner, however, must realize that post-construction appearances of groundwater may have to be dealt with on a site-specific basis. Proper functional surface drainage should be implemented and maintained at the property. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 22 X. CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon the practical field investigation conducted by our firm, and resulting laboratory tests, in conjunction with our knowledge and experience with similar soils in the Carlsbad area. The opinions, conclusions, and recommendations presented in this report are contingent upon Geotechnical Exploration, Inc. being retained to review the final plans and specifications as they are developed and to observe the site earthwork and installation of foundations. Accordingly, we recommend that the following paragraph be included on the grading and foundation plans for the project. If the geotechnical consultant of record is changed for the project, the work shall be stopped until the replacement has agreed in writing to accept the responsibility within their area of technical competence for approval upon completion of the work. It shall be the responsibility of the permittee to notify the City Engineer in writing of such change prior to the recommencement of grading and/or foundation installation work. A. Seismic Design Criteria 1. Seismic Design Criteria: Site-specific seismic design criteria for the proposed residence are presented in the following table in accordance with Section 1613 of the 2016 CBC, which incorporates by reference ASCE 7-10 for seismic design. We have determined the mapped spectral acceleration values for the site, based on a latitude of 33.1558 degrees and longitude of - 117 .3477 degrees, utilizing a tool provided by the USGS, which provides a solution for ASCE 7-10 (Section 1613 of the 2016 CBC) utilizing digitized files for the Spectral Acceleration maps. Based on our experience with similar soil Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 23 conditions, we have assigned a Site Soil Classification of D. Refer to the "USGS Design Maps Summary Report" presented as Appendix D. TABLE I Mapped Spectral Acceleration Values and Design Parameters 1.157 1.037 1.557 1.200 B. Preparation of Soils for Site Development 2. Clearing and Stripping: The existing structures to be demolished, and vegetation on the lot should be removed prior to the preparation of the building pad and areas to receive associated improvements. This includes any roots from existing trees and shrubbery. Holes resulting from the removal of root systems or other buried obstructions that extend below the planned grades should be cleared and backfilled with properly compacted fill. 3. Building Pad Surface and Subgrade Preparation: After the building pad has been cleared, stripped, and the required excavations made to remove the existing loose or disturbed surface fill, at least the upper 3 feet of pad fill soils should be removed and recompacted. The bottom of the excavation shal l be extended to expose medium dense to dense formational soils. The bottom of the excavation should be scarified to a depth of 6 inches, moisture conditioned, and compacted to the requirements for structural fill. 4 . Material for Fill: Existing on-site soils with an organic content of less than 3 percent by volume are, in general, suitable for use as fill. Imported fill material, where required, should have a low-expansion potential (Expansion Proposed Walnut Avenue Residence Project Carlsbad, California Job No . 17-11664 Page 24 s. Index of SO or less per ASTM D4829-11). In addition, both imported and existing on-site materials for use as fill should not contain rocks or lumps more than 6 inches in greatest dimension if the fill soils are compacted with heavy compaction equipment (or 3 inches in greatest dimension if compacted with lightweight equipment). All materials for use as fill should be approved by our representative prior to importing to the site. Expansive Soil Conditions: We do not anticipate that expansive soils will be encountered during grading. Should such on-site soils be used as fill, they should be moisture conditioned to at least 5 percent above optimum moisture content, compacted to 88 to 92 percent. Soils of medium or greater expansion potential should not be used as retaining wall backfill soils. If basement slabs are placed directly on medium expansive formational materials, the moisture content of the soil should be verified to be at least 3 percent above optimum, or scarification and moisture conditioning will be required. 6. Fill Compaction : All structural fill should be compacted to a minimum degree of compaction of 90 percent based upon ASTM D1557-12. Fill material should be spread and compacted in uniform horizontal lifts not exceeding 8 inches in uncompacted thickness. Before compaction begins, the fill should be brought to a water content that will permit proper compaction by either: (1) aerating and drying the fill if it is too wet, or (2) moistening the fill with water if it is too dry. Each lift should be thoroughly mixed before compaction to ensure a uniform distribution of moisture. For low expansive soils, the moisture content should be within 2 percent of optimum. We do not anticipate that medium to highly expansive soils will be encountered on the site. However, if they are encountered, the moisture content should be at Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 25 least 5 percent over optimum. Once placed, soil moisture content of the fill soils should be maintained by sprinkling daily. Medium to highly expansive soils should be compacted to between 88 and 92 percent of Maximum Dry Density. The areal extent required to remove the surficial soils should be confirmed by our representatives during the excavation work based on their examination of the soils being exposed. The lateral extent of the excavation and recompaction should be at least 5 feet beyond the edge of the perimeter ground level foundations of the new residential additions and any areas to receive exterior improvements where feasible. If heavy compaction equipment is utilized, oversize material more than 6 inches in diameter should be removed from the fill. If lightweight compaction equipment is used, oversize material more than 3 inches in diameter should be removed. Any rigid improvements founded on the existing surface soils can be expected to undergo movement and possible damage. Geotechnica/ Exploration, Inc. takes no responsibility for the performance of any improvements built on loose natural soils or inadequately compacted fills. Subgrade soils in any exterior area receiving concrete improvements should be verified for compaction and moisture within 48 hours prior to concrete placement. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 26 7. 8. No uncontrolled fill soils should remain after completion of the site work. In the event that temporary ramps or pads are constructed of uncontrolled fill soils, the loose fill soils should be removed and/or recompacted prior to completion of the grading operation. Trench and Retaining Wall Backfill: New utility trenches and retaining walls should be backfilled with imported or on-site low-expansive compacted fill; gravel is also a suitable backfill material but should be used only if space constraints will not allow the use of compaction equipment. Gravel can also be used as backfill around perforated subdrains. All backfill material should be placed in lift thicknesses appropriate to the type of compaction equipment utilized and compacted to a minimum degree of compaction of 90 percent by mechanical means. In pavement areas, that portion of the trench backfill within the pavement section should conform to the material and compaction requirements of the adjacent pavement section. In addition, the low- expansion potential fill layer should be maintained in utility trench backfill within the building and adjoining exterior slab areas. Our experience has shown that even shallow, narrow trenches (such as for irrigation and electrical lines) that are not properly compacted can result in problems, particularly with respect to shallow groundwater accumulation and migration. Temporary Slopes: We do not anticipate that significant cut lopes will be required during grading operations. Based on our subsurface investigation work, laboratory test results, and engineering analysis, temporary slopes if required should be stable for a maximum slope height of up to 12 feet and may be cut at a slope ratio of 0. 75: 1.0 in properly compacted fill so ils or Proposed Walnut Avenue Residence Project Carlsbad, Ca lifornia Job No. 17-11664 Page 27 formational materials. Some localized sloughing or raveling of the soils exposed on the slopes, however, may occur. Since the stability of temporary construction slopes will depend largely on the contractor's activities and safety precautions (storage and equipment loadings near the tops of cut slopes, surface drainage provisions, etc.), it should be the contractor's responsibility to establish and maintain all temporary construction slopes at a safe inclination appropriate to his methods of operation. No soil stockpiles or surcharge may be placed within a horizontal distance of 10 feet from the top edge of the excavation. If these recommendations are not feasible due to space constraints, temporary shoring may be required for safety and to protect adjacent property improvements. Similarly, footings near temporary cuts should be underpinned or protected with shoring. C. Design Parameters for Proposed Foundations 9. Continuous Footings: Footings for new structures or improvement s should bear on undisturbed formational materials or properly compacted fill soils. The footings should be founded at least 18 inches below the lowest adjacent finished grade when founded into properly compacted fill or into formational material. Footings located adjacent to utility trenches should have their bearing surfaces situated below an imaginary 1.5: 1.0 plane projected upward from the bottom edge of the adjacent utility trench. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 28 10. Bearing Values: At the recommended depths, footings on native, medium dense formational soil or properly compacted fill soil may be designed for allowable bearing pressures of 2,500 pounds per square foot (psf) for combined dead and live loads and increased one-third for all loads, including wind or seismic. The footings should have a minimum width of 12 inches. 11. Footing Reinforcement: All continuous footings should contain top and bottom reinforcement to provide structural continuity and to permit spanning of local irregularities. We recommend that a minimum of four No. 5 reinforcing bars be provided in the footings (two at the top and two at the bottom). Footings over 18 inches in depth should be reinforced as specified by the structural engineer. A minimum clearance of 3 inches should be maintained between steel reinforcement and the bottom or sides of the footing. Isolated square footings should contain, as a minimum, a grid of three No. 4 steel bars on 12-inch centers, both ways. In order for us to offer an opinion as to whether the footings are founded on soils of sufficient load bearing capacity, it is essential that our representative inspect the footing excavations prior to the placement of reinforcing steel or concrete. NOTE: The project Civil/Structural Engineer should review all reinforcing schedules. The reinforcing minimums recommended herein are not to be construed as structural designs, but merely as minimum reinforcement to reduce the potential for cracking and separations. 12. Lateral Loads: Lateral load resistance for structure foundations may be developed in friction between the foundation bottoms and the supporting subgrade. An allowable friction coefficient of 0.40 is considered applicable. An additional allowable passive resistance equal to an equivalent fluid weight Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 29 of 300 pcf acting against the new foundations may be used in design provided the footings are poured neat against the adjacent undisturbed formational materials and/or properly compacted fill materials. In areas where existing loose fill soils are present in front of existing or new foundations (a horizontal distance equal to 3 times the depth of embedment), the allowable passive resistance should be reduced to 150 pcf and friction coefficient to 0.35. These lateral resistance values assume a level surface in front of the footing for a minimum distance of three times the embedment depth of the footing. 13. Settlement: Settlements under foundations with building loads that comply with our recommendations are expected to be within tolerable limits for the proposed additions. For footings designed in accordance with the recommendations presented in the preceding paragraphs, we anticipate that total settlements should not exceed 1 inch and that post-construction differential angular rotation should be less than 1/240. 14. Retaining Walls: Retaining walls must be designed to resist lateral earth pressures and any additional lateral pressures caused by surcharge loads on the adjoining retained surface. We recommend that unrestrained ( cantilever) walls with level backfill be designed for an equivalent fluid pressure of 38 cf. We recommend that restrained walls (i.e., basement walls or any walls with angle points that restrain them from rotation) with level backfill be designed for an equivalent fluid pressure of 56 pcf. Unrestrained walls with up to 2.0: 1.0 sloping backfills should be designed for an equivalent fluid pressure of 52 pcf. Restrained walls with up to 2.0:1.0 sloping backfills should be designed for an equivalent fluid pressure of 76 pcf. Wherever walls will be subjected to surcharge loads, they should also be Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 30 designed for an additional uniform lateral pressure equal to one-third the anticipated vertical surcharge pressure in the case of unrestrained walls and an additional one-half the anticipated vertical surcharge pressure in the case of restrained walls. If shoring is required due to limited space constraints, the soil pressure recommended above remain applicable. For soil passive resistance, see recommendations listed below. For seismic design of unrestrained walls, we recommend that the seismic pressure increment be taken as a fluid pressure distribution utilizing an equivalent fluid weight of 15 pcf. For restrained walls, we recommend the seismic pressure increment be waived. The preceding design pressures assume that the walls are backfilled with low expansion potential materials (Expansion Index less than 50) and that there is sufficient drainage behind the walls to prevent the build-up of hydrostatic pressures from surface water infiltration. We recommend that, in addition to waterproofing, back drainage be provided by a composite drainage material such as MiraDrain 6000/6200 or equivalent. The back drain material should terminate 12 inches below the finish surface where the surface is covered by slabs or 18 inches below the finish surface in landscape areas. Waterproofing should continue to 6 inches above top of wall. A subdrain (such as Total Drain or perforated pipe in an envelope of crushed rock gravel a maximum of 1 inch in diameter and wrapped with geofabric such as Mirafi 140N), should be placed at the bottom of retaining walls. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 31 D. Backfill placed behind the walls should be compacted to a minimum degree of compaction of 90 percent using light compaction equipment. If heavy equipment is used, the walls should be appropriately temporarily braced. Shoring walls, if required,-may be designed for the same soil pressure indicated above. The soldier piles passive resistance may be calculated as 750 pcf times the diameter of the pile, times the depth of embedment of the pile below the cut surface. Concrete Slab On-Grade Criteria Slabs on-grade may only be used on new, properly compacted fill or when bearing on medium dense natural soils. 15. Minimum Floor Slab Reinforcement: Based on our experience, we have found that, for various reasons, floor slabs occasionally crack. Therefore, we recommend that all slabs on-grade contain at least a minimum amount of reinforcing steel to reduce the separation of cracks, should they occur. Slab subgrade soil should be verified by a Geotechnical Exploration, Inc. representative to have the proper moisture content within 48 hours prior to placement of the vapor barrier and pouring of concrete. New interior floor slabs should be a minimum of 4 inches actual thickness and be reinforced with No. 3 bars on 18-inch centers, both ways, placed at midheight in the slab. Soil moisture content should be kept above the optimum prior to waterproofing placement under the new concrete slab. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 32 Slab subgrade soil should be verified by a Geotechnical Exploration, Inc. representative to have the proper moisture content within 48 hours prior to placement of the vapor barrier and pouring of concrete. 16. Slab Moisture Emission: Although it is not the responsibility of geotechnical engineering firms to provide moisture protection recommendations, as a service to our clients we provide the following discussion and suggested minimum protection criteria. Actual recommendations should be provided by the Project Architect and waterproofing consultants or product manufacturer. Soil moisture vapor can result in damage to moisture-sensitive floors, some floor sealers, or sensitive equipment in direct contact with the floor, in addition to mold and staining on slabs, walls and carpets. The common practice in Southern California is to place vapor retarders made of PVC, or of polyethylene. PVC retarders are made in thickness ranging from 10-to 60- mil. Polyethylene retarders, called visqueen, range from 5-to 10-mil in thickness. These products are no longer considered adequate for moisture protection and can actually deteriorate over time. Specialty vapor retarding and barrier products possess higher tensile strength and are more specifically designed for and intended to retard moisture transmission into and through concrete slabs. The use of such products is highly recommended for reduction of floor slab moisture emission. The following American Society for Testing and Materials (ASTM) and American Concrete Institute (ACI) sections address the issue of moisture transmission into and through concrete slabs: ASTM El 745-97 (2009) Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 33 Standard Specification for Plastic Water Vapor Retarders Used in Contact Concrete Slabs; ASTM E154-88 (2005) Standard Test Methods for Water Vapor Retarders Used in Contact with Earth; ASTM E96-95 Standard Test Methods for Water Vapor Transmission of Materials; ASTM E1643-98 (2009) Standard Practice for Installation of Water Vapor Retarders Used in Contact Under Concrete Slabs; and AC! 302.2R-06 Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials. 16.1 Based on the above, we recommend that the vapor barrier consist of a minimum 15-mil extruded polyolefin plastic (no recycled content or woven materials permitted). Permeance as tested before and after mandatory conditioning (ASTM E1745 Section 7.1 and subparagraphs 7 .1.1-7.1. 5) should be less than 0.01 perms (grains/square foot/hour/per inch of Mercury) and comply with the ASTM El 745 Class A requirements. Installation of vapor barriers should be in accordance with ASTM E1643. The basis of design is 15-mil StegoWrap vapor barrier placed per the manufacturer's guidelines. Reef Industries Vapor Guard membrane has also been shown to achieve a permeance of less than 0.01 perms. We recommend that the slab be poured directly on the vapor barrier, which is placed directly on the prepared subgrade soil. 16.2 Common to all acceptable products, vapor retarder/barrier joints must be lapped and sealed with mastic or the manufacturer's recommended tape or sealing products. In actual practice, stakes are often driven through the retarder material, equipment is dragged or rolled across the retarder, overlapping or jointing is not properly implemented, etc. All these construction deficiencies reduce the retarder's effectiveness. Proposed Wa lnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 34 In no case should retarder/barrier products be punctured or gaps be allowed to form prior to or during concrete placement. 16.3 Vapor retarders/barriers do not provide full waterproofing for structures constructed below free water surfaces. They are intended to help reduce or prevent vapor transmission and/or capillary migration through the soil and through the concrete slabs. Waterproofing systems must be designed and properly constructed if full waterproofing is desired. The owner and project designers should be consulted to determine the specific level of protection required. 16.4 Following placement of any concrete floor slabs, sufficient drying time must be allowed prior to placement of floor coverings. Premature placement of floor coverings may result in degradation of adhesive materials and loosening of the finish floor materials. 17. Concrete Isolation Joints: We recommend the project Civil/Structural Engineer incorporate isolation joints and sawcuts to at least one-fourth the thickness of the slab in any floor designs. The joints and cuts, if properly placed, should reduce the potential for and help control floor slab cracking. We recommend that concrete shrinkage joints be spaced no farther than approximately 20 feet apart, and also at re-entrant corners. However, due to a number of reasons (such as base preparation, construction techniques, curing procedures, and normal shrinkage of concrete), some cracking of slabs can be expected. Structural slabs should not be provided with control joints. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 35 18. Exterior Slab Reinforcement: Exterior concrete slabs should be at least 4 inches thick. As a m inimum for protection of on-site improvements, we recommend that all nonstructural concrete slabs (such as patios, sidewalks, etc.), be founded on properly compacted and tested fill or medium dense native formation and be underlain (if needed) by 2 inches and no more than 3 inches of clean leveling sand, with No. 3 bars at 18-inch centers, both ways, at the center of the slab. Exterior slabs should contain adequate isolation and control joints. The performance of on-site improvements can be greatly affected by soil base preparation and the quality of construction. It is therefore important that all improvements are properly designed and constructed for the existing soil conditions. The improvements should not be built on loose soils or fills placed without our observation and testing. The subgrade of exterior improvements should be verified as properly prepared within 48 hours prior to concrete placement. A minimum thickness of 3 feet of properly recompacted soils should underlie the exterior slabs on-grade or they should be constructed on dense formational soils. For exterior slabs with the minimum shrinkage reinforcement, control joints should be placed at spaces no farther than 15 feet apart or the width of the slab, whichever is less, and also at re-entrant corners. Control and isolation joints in exterior slabs should be sealed with elastomeric joint sealant. The sealant should be inspected every 6 months and be properly maintained. Proposed Walnut Avenue Residence Project Carlsbad, California E. Site Drainage Considerations Job No. 17-11664 Page 36 19. Erosion Control: Appropriate erosion control measures should be taken at all times during and after construction to prevent surface runoff waters from entering footing excavations or ponding on finished building pad areas. 20. Surface Drainage: Adequate measures should be taken to properly finish- grade the lot after the structures and other improvements are in place. Drainage waters from this site and adjacent properties should be directed away from the footings, floor slabs, and slopes, onto the natural drainage direction for this area or into properly designed and approved drainage facilities provided by the project civil engineer. Roof gutters and downspouts should be installed on the residence, with the runoff directed away from the foundations via closed drainage lines. Proper subsurface and surface drainage will help minimize the potential for waters to seek the level of the bearing soils under the footings and floor slabs. Failure to observe this recommendation could result in undermining and possible differential settlement of the structure or other improvements on the site or cause other moisture-related problems. Currently, the CBC requires a minimum 1-percent surface gradient for proper drainage of building pads unless waived by the building official. Concrete pavement may have a minimum gradient of 0.5-percent. 21. Planter Drainage: Planter areas, flower beds and planter boxes should be sloped to drain away from the footings and floor slabs at a gradient of at least 5 percent within 5 feet from the perimeter walls. Any planter areas adjacent to the residence or surrounded by concrete improvements should be Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 37 F. provided with sufficient area drains to help with rapid runoff disposal. No water should be allowed to pond adjacent to the residence or other improvements or anywhere on the site. General Recommendations 22 . Pro;ect Start Up Notification: In order to reduce work delays during site development, this firm should be contacted 48 hours prior to any need for observation of footing excavations or field density testing of compacted fill soils. If possible, placement of formwork and steel reinforcement in footing excavations should not occur prior to observing the excavations; in the event that our observations reveal the need for deepening or redesigning foundation structures at any locations, any formwork or steel reinforcement in the affected footing excavation areas would have to be removed prior to correction of the observed problem (i.e., deepening the footing excavation, recompacting soil in the bottom of the excavation, etc.). 23. Construction Best Management Practices (BMPs): Construction BMPs must be implemented in accordance with the requirements of the controlling jurisdiction. Sufficient BMPs must be installed to prevent silt, mud or other construction debris from being tracked into the adjacent street(s) or storm water conveyance systems due to construction vehicles or any other construction activity. The contractor is responsible for cleaning any such debris that may be in the street at the end of each work day or after a storm event that causes breach in the installed construction BMPs. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 38 All stockpiles of uncompacted soil and/or building materials that are intended to be left unprotected for a period greater than 7 days are to be provided with erosion and sediment controls. Such soil must be protected each day when the probability of rain is 40% or greater. A concrete washout should be provided on all projects that propose the construction of any concrete improvements that are to be poured in place. All erosion/sediment control devices should be maintained in working order at all times. All slopes that are created or disturbed by construction activity must be protected against erosion and sediment transport at all times. The storage of all construction materials and equipment must be protected against any potential release of pollutants into the environment. XI. GRADING NOTES Geotechnica/ Exploration, Inc. recommends that we be retained to verify the actual soil conditions revealed during site grading work and footing excavation to be as anticipated in this "Report of Preliminary Geotechnical Investigation" for the project. In addition, the placement and compaction of any fill or backfill soils during site grading work must be observed and tested by the soil engineer. It is the responsibility of the grading contractor to comply with the requirements on the grading plans as well as the local grading ordinance. All retaining wall and trench backfill should be properly compacted. Geotechnica/ Exploration, Inc. will assume no liability for damage occurring due to improperly or uncompacted backfill placed without our observations and testing. Proposed Walnut Avenue Residence Project Carlsbad, California XII. LIMITATIONS Job No. 17-11664 Page 39 Our conclusions and recommendations have been based on available data obtained from our field investigation and laboratory analysis, as well as our experience with similar soils and formational materials located in this area of Encinitas. Of necessity, we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is, therefore, necessary that all observations, conclusions, and recommendations be verified at the time grading operations begin or when footing excavations are placed. In the event discrepancies are noted, additional recommendations may be issued, if required. The work performed and recommendations presented herein are the result of an investigation and analysis that meet the contemporary standard of care in our profession within the County of San Diego. No warranty is provided. As stated previously, it is not within the scope of our services to provide quality control oversight for surface or subsurface drainage construction or retaining wall sealing and base of wall drain construction. It is the responsibility of the contractor to verify proper wall sealing, geofabric installation, protection board installation (if needed), drain depth below interior floor or yard surfaces, pipe percent slope to the outlet, etc. This report should be considered valid for a period of two (2) years, and is subject to review by our firm following that time. If significant modifications are made to the building plans, especially with respect to the height and location of any proposed structures, this report must be presented to us for immediate review and possible revision. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 40 If the geotechnical consultant of record is changed, work shall be stopped until the replacement has agreed in writing to accept the responsibility within their area of technical competence upon completion of the work. It shall be the responsibility of the permittee to notify the governing agency in writing of such change prior to the commencement or recommencement of grading and/or foundation installation work. It is the responsibility of the owner and/or developer to ensure that the recommendations summarized in this report are carried out in the field operations and that our recommendations for design of this project are incorporated in the grading and structural plans. We should be retained to review the project plans once they are available, to verify that our recommendations are adequately incorporated in the plans. Additional or modified recommendations may be issued if warranted after plan review. This firm does not practice or consult in the field of safety engineering. We do not direct the contractor's operations, and we cannot be responsible for the safety of personnel other than our own on the site; the safety of others is the responsibility of the contractor. The contractor should notify the owner if any of the recommended actions presented herein are considered to be unsafe. The firm of Geotechnical Exploration, Inc. shall not be held responsible for changes to the physical condition of the property, such as addition of fill soils or changing drainage patterns, which occur subsequent to issuance of this report and the changes are made without our observations, testing, and approval. Proposed Walnut Avenue Residence Project Carlsbad, California Job No. 17-11664 Page 41 Once again, should any questions arise concerning this report, please feel free to contact the undersigned. Reference to our Job No. 17-11664 will expedite a reply to your inquiries. Respectfully submitted, GEOTECHNICAL EXPLORATION, INC. Jaime A. Cerros, P.E. R.C.E. 34422/G.E. 2007 Senior Geotechnical Engineer . Browning C.E.G. 2615 ject Geologist Le 1e D. Reed, President C.E.G. 999/P.G. 3391 VICINITY MAP I i --+----------+--- Thomas Guide San Diego County Edition pg 1106-E6 Rincon Walnut Avenue Project 362 Walnut A venue Carlsbad, CA. Figure No. I Job No. 17-11664 :, I I I I I a I I I a I I a I II.I :, z II.I ~ ... :, z ... ; 17· 11664-p.B.i 1 I i 'JI'l'/..(f 1 ------------------------------------------t---------------7 ;~ I I I I I I I ....k 7 I I I I I J I r r I I r J l I r I I I IOE'Mlt !----3i----- ! ... " r .... 11 UN f"""a 2.284 S.F. ,.... i,,==ll I[] 3 BEDROOM HP-4 2STORY • 38'-4' I, 'l , II ~ I II I, 13'..ff '-i; 'l 0PBl.w:E 41411'. , "" J " r,-1 11 1= UNrT2 1i!876S.F. 2 EDROOM 3STORY ' ~ I ~ q ' ~rT3 3~ 3STORY ~ HP-2 Jt 11'..ff '---' ,.,-.., Y810II P.wM -PMKMI ' \...__,, t -.. rr,. 1,875 S.F. 2BEDROOM 3STORY 2◄'.a' i ~ Ol'BIJl'#ICE 2AIIGII. 24' ... L ~ . f n 7.~:A i -, + I ! It. I I 10'..ff HP·S I tfi: I {1NF-2 1 1 F.Y.S.8. UNIT 11 UNIT 10 11•q1=,~ 2~ 1.875SF 3BEDROOM I I 3STORY 3STORY I : txm 9l1RI' I L--------·------------ UNITS .~II ., 3STORY ElffllY 1,...ff ~ I I L----------------------=------------------ NOTE: This Plot Plan is not to be used for legal purposes. Locations and dimensions are approximate. Actual property dimensions and locations of utilities may be obtained from the Approved Building Plans or the "As-Built" Grading Plans. REFERENCE: This Plot Plan was prepared from an existing undated CONCEPTUAL SITE PLAN provided by the client and from on-site field reconnaissance performed by GEi. I u,rr, g.l I i r UNfT7 1,8755', ll ~ 3BEDROOM , 23STORY 3STORY EllRY ____ -1 F-1 • ;:~ ---7 ---~----- ~~ Scale: 1 " = 20' (approximate) LEGEND ~ HP-5 • INF-1 Approximate Location of Exploratory Handpit Approximate Location of Infiltration Test PLOT PLAN Rincon Walnut Avenue Project 362 Walnut Avenue Carlsbad, CA. Figure No. II Job No. 17-11664 D Geotechnical Exploration, Inc. -g=:;,' ( November 2017) ~ ~ 5 (!) .J 11. )( w 0 w (!) ~ (!) 'EQUIPMENT DIMENSION & lYPE Of EXCAVATION Hand Tools 2' X 2' X 3' Handpit SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH ± 55' Mean Sea Level Not Encountered - - 1 -- - - - FIELD DESCRIPTION AND CLASSIFICATION _,J w g Ir DESCRIPTIOO AND REMARKS ~ ! (Grain size, Density, M:>lsture, Color) SILTY SAND. Loose. Dry. Brown. TOPSOIL SIL TY SAND , fine-to medium-grained, trace manganese nodules. Medium dense. Slightly moist. Dark red-brown. OLD PARALIC DEPOSITS (Qop s.r) 2: : ~ Bulk bag sample from 2'-3'. (/) <.) (/) :::j SM SM ~ ~'[ w~ 0 -~~ u::, ::S In ::Sw o,.-a,.z i':~ ~~ 1-----------------t----i 3.8 105.6 - 3 - - -Bottom@ 3' - - 4 - - - - - DATE LOGGED -.., 10-16-17 LOGGED BY JAB ~ ~ '[ l cf ~ ci ~~ ' ci :::i;;~ ~q +_ d wen ::, i:? ::,~ I--'W ::E--::!; :/: en 3:: z ~en -en en_ Q. :z: 1-5 i~ zo ~ ~ oa ~~ ~::E ~~ WU alu 8.2 130.8 5'-----'--.1......1---------------------'--....... _..,__.....,__.....,_ __ ......____. __ ......__......___, z i z § ir i 8 _, z 0 I w '- Y. PERCHED WATER TABLE [8J BULK BAG SAMPLE ill IN-PLACE SAMPLE ■ MODIFIED CALIFORNIA SAMPLE [I] NUCLEAR FIELD DENSITY TEST ~ STANDARD PENETRATION TEST JOB NAME Rincon -Walnut Avenue Project SITE LOCATION 362 Walnut Avenue, Carlsbad, CA JOB NUMBER REVIEWED BY LDR/JAC LOGNo. 17-11664 ;,=OK. HP-1 FIGURE NUMBER Illa ~ ~ I' EQUIPMENT DIMENSION & lYPE OF EXCAVATION ,--;;; ~ I-0 Cl i ~ 0 UJ Cl Hand Tools 2' X 2' X 2.5' Handpit SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH ± 55' Mean Sea Level Not Encountered FIELD DESCRIPTION AND CLASSIFICATION DESCRIPTION AND REMARKS (Grain size, Density, Woisture, Color) \f.}~t~ SILTY SAND. Loose. Dry. Brown. SM -f\ TOPSOIL / SM - - 1 - - - - - - . 2- - - - 3 - - - - 4 - - - - ·I '-,-,_..,..--=,-______________ _J SIL TY SAND , fine-to medium-grained, some roots to 1/2" in diameter. Medium dense. Slightly moist. Red-brown. OLD PARAUC DEPOSITS (Qop -.r) Bottom @ 2.5' DATE LOGGED " 10-16-17 LOGGED BY JAB 3.7 107.8 ~ Cl 5..__......__ ........ __________________ _.___....___.,___......_ _ __._ __ ..__ ....... __ ......__....____, z ~ z 0 0 z ii: i § t5 ! ~ "'" ~ ~ [TI ■ 0 ~ PERCHED WATER TA BLE BULK BAG SAMPLE IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE NUCLEAR FIELD DENSITY TEST STANDARD PENETRATION TEST JOB NAME Rincon -Walnut Avenue Project SITE LOCATION 362 Walnut Avenue, Carlsbad, CA JOB NUMBER REVIEWED BY LDR/JAC LOG No. 17-11664 a&-HP-2 FIGURE NUMBER Explor•tlon, Inc. lllb ~ ,J /'EQUIPMENT DIMENSION & lYPE OF EXCAVATION .... iii ~ ... 0 (!) ..J ~ 0 UJ (!) ii'. Hand Tools 2' X 2' X 2.5' Handpit SURFACE ELEVATION GROJNDWATER/ SEEPAGE DEPTH ± 55' Mean Sea Level Not Encountered t w 0 - 1 - - -- - - - 2 - - - - 3 - - - - 4 - - - - - -- - FIELD DESCRIPTION AND CLASSIFICATION g ~ DESCRIPTION AND REMARKS ~ ! (Graln size, Density, Moistwe, Color) I SILTY SAND. Loose. Dry. Brown. TOPSOIL SIL TY SAND , fine-to medium-grained. Medium dense. Slightly moist. Red-brown. OLD PARALIC DEPOSITS (Qop '"7) Bottom @ 2.5' cri (.) cri :j SM SM DATELOGGED "' 10-16-17 LOGGED BY JAB -- ~ >-c-~ ~'.! ~ ls~ ci ~ ci UJ :d~ + ci UJ Cl: ~~ ~~ tC! _j W0 u~ ::> ::> zg == !z ~(I) ~ii> ~t2 ~ (I) (I)::::;; zrw < :z ~~ ~; a.. :z ~ ~ i~ :zo ~8 ga ~~ ~~ CDU "'= 3.8 102.8 (!) 5'---...1....-L.....1.------------------....i...-_.___.,___ ........ _ __._ __ .,____., __ ......__......___. i ~ ~ a: ! § z 0 i ~ .... ~ [gJ [I] ■ 0 ~ PERCHED WATER TABLE BULK BAG SAMPLE IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE NUCLEAR FIELD DENSITY TEST STANDARD PENETRATION TEST JOB NAME Rincon -Walnut Avenue Project SITE LOCATION 362 Walnut Avenue, Car1sbad, CA JOB NUMBER REVIEWED BY LDR/JAC LOG No. 17-11664 4~~-.. , HP-3 FIGURE NUMBER l!Xploratlon. Inc. Ille ~ ,J 'EQUIPMENT DIMENSION & lYPE OF EXCAVATION ,_ $ .... 8 -' 0.. ~ @ Cl -, a.. Hand Tools 2' X 2' X 3' Handpit SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH ± 54' Mean Sea Level Not Encountered I ::c ,.... fu C - - 2 - - - - - - 3- - - - - 4 - - - - - FIELD DESCRIPTION AND CLASSIFICATION DESCRIPTION AND REMARKS en (.) (Grain size, Density, Moistn, Color) en ::::i SIL TY SAND. Loose. Dry. Brown. SM 1 FILL (Qaf) t-SM-~-------------------- I SILTY SAND , fine-to medium-grained. Medium dense. Dry to slightly moist. Brown. FILL (Qaf) SIL TY SAND , fine-to medium-grained. Medium dense. Slightly moist. Red-brown. OLD PARALIC DEPOSITS (Qop d Bottom @3' SM DATE LOGGED " 10-16-17 LOGGED BY JAB l ~ ~i ~ ~i 0 i-.: 0 w~ :::!:~ + ' II:, 0 ~~ ~~ ~q ·cl (J) WW (.) ::> ::> ::> :i:'z ~w :5~ :Sen ::,;,-~ (J) en~ z (J) -en < z ii ~; ~z ~~ i~ zo ~8 o=> ~~ _,o -~ a, (.) 3.8 105.0 Cl ~L--....1--L......l.-------------------'--...... _,._,_......L,_......L, __ ..__ .... __ ......____......___.....J z ~ z 8 z ii: i 8 _, z 0 ;:: ~ 0 ~ w \,. y ~ [I] ■ 0 ~ PERCHED WATER TABLE BULK BAG SAMPLE IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE NUCLEAR FIELD DENSITY TEST STANDARD PENETRATION TEST JOB NAME Rincon -Walnut Avenue Project SITE LOCATION 362 Walnut Avenue, Carlsbad, CA JOB NUMBER REVIEWED BY LDR/JAC LOG No. 17-11664 :;1---HP-4 FIGURE NUMBER EXpforatlon, Inc. llld ¢ ~ / EQUIPMENT DIMENSION & TYPE OF EXCAVATION Hand Tools 2' X 2' X 3' Handpit SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH :t 55' Mean Sea Level Not Encountered FIELD DESCRIPTION AND CLASSIFICATION ...J w g (( DESCRIPTION AND REMARKS ~ ! (Grain size, Density, Moisture, Color) _:!f\tt SILTY SAND. Loose. Dry. Brown. <ri cj <ri ::i SM -•\," ~ ( SM "\'-,,--,-,--~~~~ __ T_O_P_SO~I_L_~---~ SIL TY SAND , fine-to medium-grained, trace - - 1 - - - - 2 - -X roots to 3/8" in diameter. Medium dense to dense. Slightly moist. Dark red-brown. OLD PARAUC DEPOSITS (Qop '-7) Bulk bag sample from 2'-3'. -19% passing #200 sieve. ~ ~E w WCI'. g~ (.)~ :'.Sw ~o o..z zW _:::E _o - - - - 3 -I 4.6 111.1 --~ - -Bottom@ 3' - ~ 4 -~ .... Q - C, .... ~ - 0 ~ - DATE LOGGED 'I 10-16-17 LOGGED BY JAB l ~'§: l ci ~ c:i :::E~ ' 6 :::E-i'.::tj +_ d wen => => => i'.:: <n :::E ... :::E <n v,:::E ~ <n 3:\z lrW ~~ ;~ z'o ~8 o=> ~~ ~~ _,o a)(.) ~ a. C, ~L.--.1.---L.....1..-----------------.....1..-..1...--~-....L.-...I...---L--'-----L---.1..........J z ~ z 0 0 z a: I § z 0 ! ~ '- Y. PERCHED WATER TABLE ~ BULK BAG SAMPLE lil IN-PLACE SAMPLE ■ MODIFIED CALIFORNIA SAMPLE 0 NUCLEAR FIELD DENSITY TEST ~ STANDARD PENETRATION TEST JOB NAME Rincon -Walnut Avenue Project SITE LOCATION 362 Walnut Avenue, Car1sbad, CA JOB NUMBER REVIEWED BY LDR/JAC LOGNo. 17-11664 ,:;a-····" HP-5 FIGURE NUMBER 1!:xpforatlon, Inc. Ille ~ ~ 135 \ , \ \ \ \ \ ' .... , \ \ l 130 J., \ \ l I ' \ .. ~\ \ , ~ \ ' 125 ,~ \ ~ \. \ ' \ 1 Source of Material HP-1 @2.0' \ \ \ ' Description of Material SIL TY SAND {SM}, Brown 120 \ \ l \ \ Test Method ASTM D1557 Method A \ \ \ \ \ 115 \ \ \ ' \ \ TEST RESULTS \ ' \ \. Maximum Dry Density 130.8 PCF \ ' 110 \ \ Optimum Water Content 8.2 % 'g_ \ ~ \ \ \ Expansion Index (El) \ \ <i5 \ \ \ z 105 w \ \ l 0 \ \ >-a:: \ \. 0 \ \ ' 100 \ I\ \. ~ \ \. Curves of 100% Saturation ' I\ ' \. \. for Specific Gravity Equal to: I\ \ 2.80 95 \ \ \ ' I\. 2.70 \. \ \. ' ., ' 2.60 ' \ I\. 90 \. ' ~ \. \ "' ?I ' \. ' ~ '\ '\ ... '\ ' 'I\. 0 ~ 85 \. I\. a, ' " ~ w u. \. ' ' .. w (!) \. ' ;;: ' '\ ..... (!) ~ 80 ' " ....... z -' ' ' ....... ~ '-"-.... ~ z 0 ~ "-I ~ °' I'... i 75 [',_ 0 5 10 15 20 25 30 35 40 45 0 ii: t:l WATER CONTENT,% I 4r.-4~. Geotechnlcal MOISTURE-DENSITY RELATIONSHIP w + Exploration, Inc. Figure Number: IV z 0 ' ........ V. Job Name: Rincon -Walnut Avenue Project ;: ~~~ u ~ ~ Site Location: 362 Walnut Avenue, Carlsbad, CA ::E 0 Job Number: 17-11664 u I Pacific .... v,. ~ _. l~ltP"r ~ .... i,~·-. -.i&Gs -..11111 ..... ~1cun .... ~e►..,oXl"clG~.-.•¥1 ~ IIDOi:lllfllll": .... _,UiCS &11'W .,._.,,.,.,..... tDEM'•J ~ M.,w,-u..c ~ • .,. .-,n.-(1,111(...,.._,, ._ N 04• ,, .. r'ld ~ UM ~•UfM '°"911 __,,.,..,U"o.,,.-,a,7 ...,,.~, ~V.~.§ ~ l'UftlP.,...~•-~MCL'S ~• , .. ".,.~~~"'~~ s·-.·°""".-..rdi.c~• ...._....,.c~•--.C'IIP'eU'.~ ~a.....,. Sc"~ ... 't~...,.. ... ~,fllfwt ~~ ,ooe,~ ... C..-IDffl, 0,t:..a, .... O,CW"_....,. Al ... -...s ._)91_,.,_~ra,"9,..,....,.. ~~ ............ -.. c::.w ....... c..~......,. n.0....,111~---fllO--........ ••>41w'• ............ .,.~Cl,p(,t• Rincon-362-2008-OC-geo.ai Rincon Walnut Avenue Project 362 Walnut Avenue Carlsbad, CA. EXCERPT FROM GEOLOGIC MAP OF THE OCEANSIDE 30' x 60' QUADRANGLE, CALIFORNIA Compiled by Michael P. Kennedy1 and Siang S. Tan1 2007 Digital preparation by Kelly R. Bovard', Rachel M Alvarez', Michael J. Watson-2, and Car1os I. Gutierrez' t. 0..,,..IN_C...__,.,..,Calf[lllftll~......., 2 IJ.$ a.:,,.._..,.,.,.o.oerw .... 1 ... ...-~-~ ......... i7. ~-- ~1'1 ..... ,. __ ONSHORE MAP SYMBOLS DESCRIPTION OF MAP UNITS O.nt>ct~bc ... cai1colo&o<1D1<;-wt>cn..-.Jed 70 _!,_-%---F1al1-Sclld ~11,,o -1)' loo&locl; tuMd ,._. ~ locolod; doaod wun -U•.,0,-Wock.D•-Wook.A,-mlouahaindiool, ,,_.,.,....,dlportaal,i-. -----. 0 @ ...1!. ~ e ...:! + .. ~ ..... .1! • "'1Uclln--..-.US--.ayloaou4dododwbon......W S~wlcr>....-lylOCllld;cPltdWMt.......W K&11-tnni" _.... diu Ootedd,pnl•...-Cloffddop,,aa,ml!lsmefeullzao,. Lalldalldo-Anows-.,.)IDOCipol-or_....._Quclled ___ il q,,,rim,lol<. SC:rik• .and dip of blick ·-Oftrturud \"rnkal B•rtmntal Strtkt and d1P or tpeow foUMMa lndlned \',rtlul -· .... -or 1p ... joint> """* ~rtkal Strtke and -•f aMltCDIJrpbk Jtl:t.ltloo J.actiNd S.rtkl •nd d_, or MdmtntUJ Jolnll V.rtk•I I OoP5--7 I Units 6-7 Old paralic deposits, undMded Figure No. V Job No. 17-11664 ;,r-,1~ E.pforatlon, Inc. ~ z November2017 -,,. --.. ... -... ------.. ----... .. ... .. --... .. ------- --- APPENDIX A UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION Coarse-grained (More than half of material is larger than a No. 200 sieve) GRAVELS, CLEAN GRAVELS (More than half of coarse fraction is larger than No. 4 sieve size, but smaller than 3") GRAVELS WITH FINES (Appreciable amount) SANDS, CLEAN SANDS (More than half of coarse fraction is smaller than a No. 4 sieve) SANDS WITH FINES (Appreciable amount) GW GP GC SW SP SM SC Well-graded gravels, gravel and sand mixtures, little or no fines. Poorly graded gravels, gravel and sand mixtures, little or no fines. Clay gravels, poorly graded gravel-sand-silt mixtures Well-graded sand, gravelly sands, little or no fines Poorly graded sands, gravelly sands, little or no fines. Silty sands, poorly graded sand and silty mixtures. Clayey sands, poorly graded sand and clay mixtures. Fine-grained (More than half of material is smaller than a No. 200 sieve) SILTS AND CLAYS Liquid Limit Less than 50 Liquid Limit Greater than 50 HIGHLY ORGANIC SOILS ML CL OL MH CH OH PT Inorganic silts and very fine sands, rock flour, sandy silt and clayey-silt sand mixtures with a slight plasticity Inorganic clays of low to medium plasticity, gravelly clays, silty clays, clean clays . Organic silts and organic silty clays of low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and other highly organic soils ... --... -----... -... -.. -------... .. .. -.. .. -.. .. -... ----... - APPENDIXB INFILTRATION TEST DATA AND INFILTRATION RATE CALCULATIONS fl II fl II fl II fl 11 fl 11 II II fl fl fl II II II II Simple Open Pit Falling Head Test Sheet Project Name: Rincon Walnut Ave Project Project No. 17-11664 Date Excavated: 10/16/17 Test Hole No: INF-1 Initial Time (Minutes) Final Time (Minutes) 955 1025 1025 1110 1115 1215 Time interval (minutes) 30 45 60 Initial Water Level (inches) 30.000 30.000 30.000 Tested By: JAB Soil Classification: SM Depth of Test Hole: 36" Test Hole Dia: 24" Final Water Level (inches) 36.000 36.000 36.000 Change in water (inches) 6.000 6.000 6.000 Falling Head Rate (min/Inches) 5.000 7.500 10.000 fl II fl fl II II 111111 fl 11111111 II ti fl fl II Simple Open Pit Falling Head Test Sheet Project Name: Rincon Walnut Ave Project Project No. 17-11664 Date Excavated: 10/16/17 Test Hole No: INF-2 Initial Time (Minutes) Final Time (Minutes) 1000 1020 1022 1107 1107 1207 Time interval (minutes) 20 45 60 Initial Water Level (inches) 30.500 30.000 30.000 Tested By: JAB Soll Classification: SM Depth of Test Hole: 36.5" Test Hole Dia: 24" Final Water Level (inches) 36.500 36.500 36.500 Change in water (inches) 6.000 6.500 6.500 Falllng Head Rate (min/inches) 3.333 6.923 9.231 Simple Open Pit Rate to Infiltration Rate Conversion (Porchet Method) Project Name: Rincon Walnut Ave Project Calculated By: JAB Project No. 17-11664 Checked By: Test Hole No: INF-1 Test Hole Dia: 24" Date: 10/17/2017 Date: Depth of Test Hole: 36" Porchet Corrections Infiltration rate=((delta h*60r)/(delta t*(r+2 h avg)) Test EB Depth Delta T Water Depth Water Depth hl h2 delta h havg No. (inches) (min) 1 (inches) 2 (inches) (inches) (inches) (inches) finches) 1 36 30 30.000 36.000 6.000 0.000 6.000 3.000 2 36 45 30.000 36.000 6.000 0.000 6.000 3.000 3 36 60 30.000 36.000 6.000 0.000 6.000 3.000 4 5 6 7 8 9 r (radius) delta delta t*fr+2 h (inches) h*60r av_g} 12 4320 540 12 4320 810 12 4320 1080 Infiltration rate (in/hr) 8.000 5.333 4.000 Simple Open Pit Rate to Infiltration Rate Conversion (Porchet Method) Project Name: Rincon Walnut Ave Project Project No. 17-11664 Test Hole No: INF-2 Test EB Depth DeltaT Water Depth No. (inches) (min) 1 (inches} 1 36.5 20 30.500 2 36.5 45 30.000 3 36.5 60 30.000 4 5 6 7 8 9 Calculated By: JAB Checked By: Date: 10/17/17 Date: Test Hole Dia: 24" Depth of Test Hole: 36.5" Porchet Corrections Infiltration rate={{delta h*60r)/(delta t*(r+2 h avg)) Water Depth hl h2 delta h h avg r (radius) 2 (inches) (inches) (inches) (inches} (inches) (inches) 36.500 6.000 0.000 6.000 3.000 12 36.500 6.500 0.000 6.500 3.250 12 36.500 6.500 0.000 6.500 3.250 12 delta h*60r 4320 4680 4680 delta t*(r+2 Infiltration rate h avg) (in/hr) 360 12.000 832.5 5.622 1110 4.216 APPENDIXC USDA WEB SOIL SURVEY MAP ll' 9'22"N ll'9'19"N N A Soil Map-San Diego County Area, California Map Scllle: 1:516 r prttEd on A por1rci1t (&5" x 11") sheet. ---===,------======Mite's 0 5 10 ~ ----=====--------=======!'et 0 25 SI 100 1!11 Mnp ~ web Men:2IXr Cmle'ooordnalie:s: WGS84 Edge tics: UTM zone llN WGS84 Natural Resources Conservation Service Web Soll Survey National Cooperative Soll Survey I - 10/30/2017 Page 1 of 3 33' 9' 1!7N ~ Soil Map-San Diego County Area, California MAP LEGEND MAP INFORMATION Alff of Interest (AOI) D Area of Interest (AOI) Solls =:J Soll Map Unit Polygons -Soil Map Unit Lines Ii Soll Map Unit Points Special Point Features t2) Blowout ~ Borrow Pit )( Clay Spot ( Closed Depression X Gravel Pit Gravelly Spot ~ Landfill A. Lava Flow .;k. Marsh or swamp ~~-Mine or Quarry Mlscelleneous Water \.I Perennial Water Rock Outcrop + SaRne Spot Sandy Spot .. ==, Severely Eroded Spot , Sinkhole ,, .. Slide or Slip II Sodlc Spot Natural Resources Conservation Service = Spoil Area ,.. (I Stony Spot ~ .. Very Stony Spot ~ .. Wei.Spot '·) \ Other #-Special Line Features Water Features Streams and Canals Transportation ...... -Rails lnterstata Highways US Routes Major Roads Local Roads Background • Aerial Photography Web Soil Survey National Cooperative Soil Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soll Survey Area: San Diego County Area, California Survey Area Data: Version 10, Sep 12, 2016 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial Images were photographed: Nov 3, 2014--Nov 22,2014 The orthopholo or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 10/30/2017 Page 2of 3 Soil Map-San Diego County Area, California Map Unit Legend I I Map Unit Symbol !MIC I I Totals for Area of Interest Natural Resources Conservation Service Map Unit Name I Acres In AOI Marina loamy coarse sand, 2 l to 9 percent slopes 1 -- Web Soil Survey National Coaperative Soil Survey Percent of AOI 0.6 . 0.6 100.0%; 100.0% ! 10/30/2017 Page 3 of 3 Map Unit Description: Marina loamy coarse sand, 2 to 9 percent slopes-San Diego County Area, California San Diego County Area, California MIC-Marina loamy coarse sand, 2 to 9 percent slopes USD4 Natural Resources a. Conservation Servlc• Map Unit Setting National map unit symbol: hbdz Mean annual air temperature: 57 to 61 degrees F Frost-free period: 330 to 350 days Farmland classification: Prime farmland if irrigated Map Unit Composition Marina and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Marina Setting Landform: Ridges Down-slope shape: Linear Across-slope shape: Linear Parent material: Eolian sands derived from mixed sources Typical profile H1 -0 to 10 inches: loamy coarse sand H2-10 to 57 inches: loamy sand, loamy coarse sand H2 -10 to 57 inches: sand, coarse sand H3 -57 to 60 inches: H3 -57 to 60 inches: Properties and qualities Slope: 2 to 9 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): 3s Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No Web Soll Survey National Cooperative Soll Survey 10/30/2017 Page 1 of2 Map Unit Description: Marina loamy coarse sand, 2 to 9 percent slopes-San Diego County Area, California Minor Components Carlsbad Percent of map unit: 5 percent Hydric soil rating: No Chesterton Percent of map unit: 5 percent Hydric soil rating: No Corralltos Percent of map unit: 5 percent Hydric soil rating: No Data Source Information Soll Survey Area: San Diego County Area, California Survey Area Data: Version 10, Sep 12, 2016 Natural Resources Conservation Service Web Soll Survey National Cooperative Soll Survey 10/30/2017 Page 2 of2 APPENDIXD USGS DESIGN MAPS SUMMARY REPORT 1112/2017 Design Maps Summary Report EUSGS Design Maps Summary Report User-Specified Input Report Title Rincon Walnut Avenue Thu November 2, 2017 19:59:02 UTC Bulldlng Code Reference Document ASCE 7-10 Standard (which utilizes USGS hazard data available In 2008) Site Coordinates 33.1558°N, 117 .3477°W Site Soil Classification Site Class D -"Stiff Soil" Risk Category I/II/Ill USGS-Provided Output S5 = 1.157 g S1 = 0.443 g SMs = 1.200 g SMl = 0.690 g ' 11 -~- ·.,,!••,?•-~-.,, :,!etlt11.m'' 5 05 = 0.800 g S01 = 0.460 g bcond~• For information on how the SS and S1 values above have been calculated from probabilistic (risk-targeted) and determlnlstlc ground motions in the direction of maximum horizontal response, please return to the application and select the "2009 NEHRP" building code reference document. ,, ' ' ,, 'I ·:;, ,. 'I~· :.,::. I ~!I~ -l For PGAw TL, CRS, and CR, values, please view the detajled report. Although this information is a product of the U.S. Geological Survey, we provide no warranty, expressed or implied, as to the accuracy of the data contained therein. This tool is not a substitute for technical subject-matter knowledge. https://earthquake .usgs.gov/cn 1 /designmaps/us/summary.php?template=mlnlmal&latitude=33.1558&Iongitude=-117 .34 77 &siteclass=3&riskcategory=O... 1 /1 11/2/2017 Design Maps Detailed Report IIIJSGS Design Maps Detailed Report ASCE 7-10 Standard (33.1558°N, 117.3477°W) Site Class D -"Stiff Soil", Risk Category I/II/III Section 11.4.1 -Mapped Acceleration Parameters Note: Ground motion values provided below are for the direction of maximum horizontal spectral response acceleration. They have been converted from corresponding geometric mean ground motions computed by the USGS by applying factors of 1.1 (to obtain S5) and 1.3 (to obtain 51). Maps in the 2010 ASCE-7 Standard are provided for Site Class B. Adjustments for other Site Classes are made, as needed, in Section 11.4.3. From Figure 22-1 c11 Ss = 1.157 g From Figure 22-2 c21 S1 = 0.443 g Section 11.4.2 -Site Class The authority having jurisdiction (not the USGS), site-specific geotechnical data, and/or the default has classified the site as Site Class D, based on the site soil properties in accordance with Chapter 20. Table 20.3-1 Site Classlflcatlon Site Class A. Hard Rock B. Rock C. Very dense soil and soft rock D. Stiff Soil E. Soft clay soil F. Soils requiring site response analysis in accordance with Section 21.1 Nor Nch -Vs Su >5,000 ft/S N/A N/A 2,500 to 5,000 ft.ls N/A N/A 1,200 to 2,500 ft.ls >50 >2,000 psf 600 to 1,200 ft.ls 15 to 50 1,000 to 2,000 psf <600 ft./s <15 <1,000 psf Any profile with more than 10 ft of soil having the characteristics: • Plasticity index PI > 20, • Moisture content w ~ 40%, and • Undrained shear strength su < 500 psf See Section 20.3.1 For SI: lft/s = 0.3048 m/s l lb/ft2 = 0.0479 kN/m2 https://earthquake .usgs.gov/cn 1 /deslgnmaps/us/report.php?template=minimal&latitude=33.155B&longitude=-117 .34 77 &siteclass=3&riskcategory=0&e ... 1 /6 11/2/2017 Design Maps Detailed Report Section 11.4.3 -Site Coefficients and Risk-Targeted Maximum Considered Earthquake ct1¼1;_g) Spectral Response Acceleration Parameters Table 11.4-1: Site Coefficient F. Site Class Mapped MCE R Spectral Response Acceleration Parameter at Short Period 55 :S 0.25 S5 = 0.50 S5 =0.75 55 = 1.00 55 2: 1.25 A 0.8 0.8 0.8 0.8 0.8 B 1.0 1.0 1.0 1.0 1.0 C 1.2 1.2 1.1 1.0 1.0 D 1.6 1.4 1.2 1.1 1.0 E 2.5 1.7 1.2 0.9 0.9 F See Section 11.4. 7 of ASCE 7 Note: Use straight-line interpolation for intermediate values of S5 For Site Class = D and S5 = 1.157 g, F. = 1.037 Table 11.4-2: Site Coefficient F, Site Class Mapped MCE R Spectral Response Acceleration Parameter at 1-s Period S1 :S 0.10 51 = 0.20 S1 = 0.30 SI= 0.40 s1 2: a.so A 0.8 0.8 0.8 0.8 0.8 B 1.0 1.0 1.0 1.0 1.0 C 1.7 1.6 1.5 1.4 1.3 D 2.4 2.0 1.8 1.6 1.5 E 3.5 3.2 2.8 2.4 2.4 F See Section 11.4. 7 of ASCE 7 Note: Use straight-line interpolation for intermediate values of S1 For Site Class = D and S1 = 0.443 g, F, = 1.557 https://earthqua ke .usgs. gov/en 1 /designmaps/uslreport.php?template=mlnimal&latitude-=33.1558&Iongitude=-117 .34 77 &slteclass=3&riskcalegory=0&e... 2/6 11/2/2017 Design Maps Detailed Report Equation (11.4-1): SMs = FaSs = 1.037 X 1.157 = 1.200 g Equation (11.4-2): SMl = FvSl = 1.557 X 0.443 = 0 .690 g Section 11.4.4 -Design Spectral Acceleration Parameters Equation (11.4-3): Sos=¾ SMs = ¾ X 1.200 = 0.800 g Equation (11.4-4): S01 = ¾ SM1 = ¾ X 0.690 = 0.460 g Section 11.4.5 -Design Response Spectrum From Figure 22-12 c3J TL = 8 seconds Figure 11.4-1: Design Response Spectrum I I ... , ............. , ........... .. 1' T<T0 : s. ::S1111 (0.4 + 0.6 T /T0 ) T1 :Ii T :Ii T5 : S1 = S05 T5 < T :S TL: S1 = S01 /T T> TL: s. =S0,TL (T1 :-.,,. I st https://earthquake.usgs.gov/cn 1 /designmaps/us/report.php?template=mlnlmal&latitude=33.1558&1ongitude=-117 .34 77 &siteclass=3&riskcategory=O&e.. . 3/6 11/2/2017 Design Maps Detailed Report Section 11.4.6 -Risk-Targeted Maximum Considered Earthquake (MCER) Response Spectrum The MCER Response Spectrum is determined by multiplying the design response spectrum above by ~· 1.200 1.5. I I I I Sw, • 0.690 -1-----------4 ----------I I I I I I To-0. 15 l~ -C.575 1.0 P@l'1od. T (~~) https://earthquake .usgs.gov/cn1 /designmaps/us/report.php?template=minlmal&latitude=33 .1558&longitude=-117 .34 77 &siteclass=3&riskcategory=0&e. . . 4/6 11/2/2017 Design Maps Detailed Report Section 11.8.3 -Additional Geotechnical Investigation Report Requirements for Seismic Design Categories D through F From Figure 22-7 t4J PGA = 0.460 Equation (11.8-1): PGAM = FPGAPGA = 1.040 x 0.460 = 0.479 g Table 11.8-1: Site Coefficient FPGA Site Mapped MCE Geometric Mean Peak Ground Acceleration, PGA Class PGA S PGA = PGA = PGA = PGA.? 0.10 0.20 0.30 0.40 0.50 A 0.8 0.8 0 .8 0.8 0.8 B 1.0 1.0 1.0 1.0 1.0 C 1.2 1.2 1.1 1.0 1.0 D 1.6 1.4 1.2 1.1 1.0 E 2.5 1.7 1.2 0.9 0.9 F See Section 11.4. 7 of ASCE 7 Note: Use straight-line interpolation for intermediate values of PGA For Site Class= D and PGA = 0.460 g, FPG" = 1.040 Section 21.2.1.1 -Method 1 (from Chapter 21 -Site-Specific Ground Motion Procedures for Seismic Design) From Figure 22-17 csi CRS = 0.937 From Figure 22-18 t&J CR] = 0.990 https://earthquake .usgs.gov/cn 1 /designmaps/us/report.php?template=minimal&latltude=33.1558&Iongltude=-1 17 .34 77 &siteclass=3&riskcategory=O&e.. . 5/6 11/2/2017 Design Maps Detailed Report Section 11.6 -Seismic Design Category Table 11.6-1 Seismic Design Category Based on Short Period Response Acceleration Parameter RISK CATEGORY VALUE OF Sos I or II Ill IV Sos< 0.167g A A A 0.167g S S0s < 0.33g B B C 0.33g S S05 < 0.50g C C D O.SOg :S S0 s D D D For Risk Category = I and S05 = 0.800 g, Seismic Design Category = D Table 11.6-2 Seismic Design Category Based on 1-S Period Response Acceleration Parameter RISK CATEGORY VALUE OF S01 I or II III IV S01 < 0.067g A A A 0.067g S S01 < 0.133g B B C 0.133g :S S01 < 0.20g C C D 0.20g S S0 1 D D D For Risk Category = I and S01 = 0 .460 g, Seismic Design Category = D Note: When S1 Is greater than or equal to 0.75g, the Seismic Design Category is E for buildings in Risk Categories I, II, and III, and F for those in Risk Category IV, irrespective of the above. Seismic Design Category = "the more severe design category in accordance with Table 11.6-1 or 11.6-2" = D Note: See Section 11.6 for alternative approaches to calculating Seismic Design Category. References 1. Figure 22-1: https://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-1. pdf 2. Figure 22-2: https://earthquake.usgs.gov/hazards/designrnaps/downloads/pdfs/2010_ASCE-7 _Figure_22-2. pdf 3. Figure 22-12: https://earthquake.usgs.gov/hazards/designrnaps/downloads/pdfs/2010_ASCE-7 _Figure_22-12.pdf 4. Figure 22-7: https ://earthquake. usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-7 .pdf 5. Figure 22-17: https ://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-17 .pdf 6. Figure 22-18: https :/ /earthquake. usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-18.pdf https:/learthquake .usgs.gov/cn 1 /designmaps/us/report.php?lemplate=minimal&latitude=33.1558&Iongitude=-117 .34 77 &siteciass=3&riskcategory=0&e. . . 6/6