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Home My WebLink AboutPA2017-218_20170621_WQ Infiltration Investigation Report 6-2017 June 21, 2017 Project No. 1704-CR Melia Homes Ms. Christine Harmon-Harris 8951 Research Drive Irvine, California 92618 Attention: Ms. Christine Harmon-Harris Subject: Infiltration Evaluation Proposed Multi-Family Residential Development Mariner’s Square Project North of Westcliff Plaza, West of Irvine Avenue, and South of Mariners Drive Newport Beach, Orange County, California References: See Page 5 Dear Ms. Harmon-Harris: As requested and authorized, GeoTek, Inc. (GeoTek) has performed an infiltration evaluation at the subject property. The intent of this study is to evaluate the infiltration properties of the underlying soils in the proposed single-family residence development area. This report presents the results of the infiltration testing completed by GeoTek. Site and Project Description The subject site is located north of Westcliff Plaza, east of Irvine Avenue and south of Mariners Drive in the city of Newport Beach, Orange County, California. Based on our recent site reconnaissance completed on June 14, 2017, the area to be developed currently has 20 multi- family residential buildings with associated landscape, parking and drive areas. The irregular shaped site is approximately 5.76 acres and can be considered as having relatively flat to gently sloping terrain with existing elevations ranging from approximately 94 to 83 mean sea level (msl) and generally sloping down to the southwest. Site specific topography is shown on the enclosed Site Location Map (Figure 1). Groundwater was encountered in three of the deeper borings excavated at the site by this firm. The shallowest reading of groundwater was 11 feet bgs in the southwest corner of the site. The deepest reading of groundwater was 11.5 feet bgs in the northwestern and southcentral portion of the site. This groundwater is considered to be in a perched condition as materials beneath are not saturated to the depth explored (51 feet bgs). MELIA HOMES Project No. 1704-CR Infiltration Evaluation June 21, 2017 Newport Beach, Orange County, California Page 2 Based on our understanding of proposed development, the project will consist of the construction of a multi-family residential community consisting of approximately 14 buildings with associated landscape, parking and drive areas. The proposed structures are anticipated to be two- to three-story. Storm water infiltration systems are also proposed. It is anticipated that the systems will have a depth of up to approximately five feet below existing grade. Infiltration Testing Two test borings were excavated for infiltration purposes to five feet below ground surface with a hollow stem auger drill rig within the subject property. The two test boring locations can be seen on the Boring and Infiltration Location Map (Figure 2). Infiltration testing was performed in two of the excavations within the lower 24 inches by a representative from our firm in general conformance with the referenced document. The depths tested were intended to correlate to the bottom several feet of the projected storm water infiltration systems. The infiltration rates are presented in the following table for each of the borings after the rates had stabilized. Boring No. Approximate depth of testing (feet) Infiltration Rate (inches per hour) B-3 5 0.07 B-5 5 0.20 Copies of the percolation data sheets and conversion sheets (Porchet Method) are included in Appendix B. Given the nature of the materials encountered and infiltration rates attained in the boring excavations tested, the number of test performed should be considered adequate for preliminary design purposes. Over the lifetime of the storm water disposal areas, the infiltration rates may be affected by silt build up and biological activities, as well as local variations in near surface soil conditions. As per the Infiltration Rate Evaluation Protocol and Factor of Safety Recommendations, a factor of safety of 2.0 should be applied to the infiltration rate for each test. MELIA HOMES Project No. 1704-CR Infiltration Evaluation June 21, 2017 Newport Beach, Orange County, California Page 3 LIMITATIONS The materials observed on the project site appear to be representative of the area; however, soil materials vary in character between excavations and natural outcrops or conditions exposed during site construction. Site conditions may vary due to seasonal changes or other factors. GeoTek, Inc. assumes no responsibility or liability for work, testing or recommendations performed or provided by others. Our conclusions and recommendations are professional opinions that are limited to the extent of the available data. Observations during construction are important to allow for any change in recommendations found to be warranted. These opinions have been derived in accordance with current standards of practice and no warranty is expressed or implied. Standards of practice are subject to change with time. MELIA HOMES Project No. 1704-CR Infiltration Evaluation June 21, 2017 Newport Beach, Orange County, California Page 4 The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to call our office. Respectfully submitted, GeoTek, Inc. Edward H. LaMont CEG 1892, Exp. 07/31/18 Principal Geologist Enclosures: Figure 1 – Site Location Map Figure 2 – Boring and Infiltration Location Map Appendix A – Logs of Exploratory Borings Appendix B – Percolation Data Sheets and Conversion Sheets (Porchet Method) Distribution: (1) Addressee via email (PDF file) G:\Projects\1701 to 1750\1704CR Melia Homes Mariner's Square Newport Beach\Geotechnical Investigation\1704-CR Infiltration Report.doc MELIA HOMES Project No. 1704-CR Infiltration Evaluation June 21, 2017 Newport Beach, Orange County, California Page 5 REFERENCES Morton, D.M., 2004, Preliminary Digital Geologic Map of the Santa Ana 30’x60’ Quadrangle, Southern California; U.S Geological Survey Report 99-172, scale 1:100,000. Orange County Flood Control and Water Conservation District, “Infiltration Rate Evaluation Protocol and Factor of Safety Recommendations,” dated May 19, 2011. Figure 1 Site Location Map Melia Homes Proposed Multi-family Residential Development 1244 Irvine Avenue Newport Beach,Orange County, California GeoTek Project No. 1704-CR Modified from USGS 7.5-minute Newport Beach Topographic Map SUBJECT AREA OF DEVELOPMENT Figure 2 Boring and Infiltration Test Location Map Melia Homes Mariner’s Square 1244 Irvine Avenue Newport Beach, Orange County, California GeoTek Project No. 1704-CR B-1 B-2 B-3 B-4B-5 LEGEND Approximate Location of Exploratory Boring Approximate Location of Exploratory Infiltration Test Boring SUBJECT AREA OF IMPROVEMENT APPENDIX A LOGS OF EXPLORATORY BORINGS Mariner’s Square Project Newport Beach, Orange County, California Project No. 1704-CR MELIA HOMES Project No. 1704-CR Infiltration Evaluation June 21, 2017 Newport Beach, Orange County, California Page A-1 BORING LOG LEGEND The following abbreviations and symbols often appear in the classification and description of soil and rock on the log of borings: SOILS USCS Unified Soil Classification System f-c Fine to coarse f-m Fine to medium GEOLOGIC B: Attitudes Bedding: strike/dip J: Attitudes Joint: strike/dip C: Contact line ……….. Dashed line denotes USCS material change Solid Line denotes unit / formational change Thick solid line denotes end of the boring (Additional denotations and symbols are provided on the log of boring) GeoTek, Inc.LOG OF EXPLORATORY BORING 3" AC 4" CAB ML ---Ring ---Small Bulk ---No Recovery ---Water Table LEGENDSample type:---SPT ---Large Bulk 20 25 30 15 Trench backfilled with soil cuttings 10 5 BORING TERMINATED AT 5 FEET No groundwater encountered F sandy SILT, brown to orangish brown, moist Dry Density(pcf)Depth (ft)Sample TypeBlows/ 6 inSampleNumberOthersMATERIAL DESCRIPTION AND COMMENTS ARTIFICIAL FILL (Qafc) SAMPLES USCS Symbol BORING NO.: B-3 Laboratory Testing Water Content(%)LOCATION:See Boring Location Map DATE:6/14/2017 PROJECT NO.:1704-CR HAMMER:140lb/30in RIG TYPE: PROJECT NAME:Mariners Square DRILL METHOD:Hollow Stem Auger OPERATOR: CLIENT:Malea Homes DRILLER:LOGGED BY:DRW GeoTek, Inc.LOG OF EXPLORATORY BORING 3" AC 4" CAB ML ---Ring ---Small Bulk ---No Recovery ---Water Table LEGENDSample type:---SPT ---Large Bulk 20 25 30 15 No groundwater encountered Trench backfilled with soil cuttings 10 F-m sandy SILT, brown, moist 5 BORING TERMINATED AT 5 FEET Dry Density(pcf)OthersMATERIAL DESCRIPTION AND COMMENTS ARTIFICIAL FILL (Qafc) SAMPLES USCS Symbol BORING NO.: B-5 Laboratory Testing Depth (ft)Sample TypeBlows/ 6 inSampleNumberWater Content(%)LOCATION:See Boring Location Map DATE:6/14/2017 PROJECT NO.:1704-CR HAMMER:140lb/30in RIG TYPE: PROJECT NAME:Mariners Square DRILL METHOD:Hollow Stem Auger OPERATOR: CLIENT:Malea Homes DRILLER:LOGGED BY:DRW APPENDIX B PERCOLATION DATA SHEETS AND CONVERSION SHEETS Mariner’s Square Project Newport Beach, Orange County, California Project No. 1704-CR Equation -It = Havg = (HO+HF)/2 = It =Inches per Hour Client:Melia Homes Project:Mariner's Square Project Initial Depth to Water, DO =7.25 Project No:1704-CR Date:6/15/2017 Boring No.B-3 Percolation Rate (Porchet Method) Time Interval,Δt =30 Final Depth to Water, DF =8.25 Test Hole Radius, r =4 0.07 Total Test Hole Depth, DT =60 ΔH (60r) Δt (r+2Havg) HO = DT - DO =52.75 HF = DT - DF =51.75 52.25 ΔH =ΔD = HO- HF =1 Equation -It = Havg = (HO+HF)/2 = It =Inches per Hour0.20 Total Test Hole Depth, DT =60 ΔH (60r) Δt (r+2Havg) HO = DT - DO =55.25 HF = DT - DF =52.5 ΔH =ΔD = HO- HF =2.75 53.875 Final Depth to Water, DF =7.5 Test Hole Radius, r =4 Initial Depth to Water, DO =4.75 Time Interval,Δt =30 Client:Melia Homes Project:Mariner's Square Project Project No:1704-CR Date:6/15/2017 Boring No.B-5 Percolation Rate (Porchet Method)