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PA2021-285_20230608_WQMP dated 11-11-2021
Water Quality Management Plan (WQMP) BLAND RESIDENCE Lot 17 & Portion of Lot 19, Block 4, Section 5 of Balboa Island APN 050-184-17 125 East Bayfront, Newport Beach, California Prepared for: GARRETT AND HEATHER BLAND 14975 Corona Del Mar Pacific Palisades, CA 90272 Prepared by: TOAL ENGINEERING, INC. 139 Avenida Navarro, San Clemente, CA 92672 www.toalengineering.com Contact: Adam Toal, R.C.E. 59275 (949) 492-8586 atoal@toalengineering.com Prepared on: NOVEMBER 11, 2021 Template Prepared: December 20, 2013 Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Owner’s Certification Project Owner’s Certification Permit/Application No. TBD Grading Permit No. PC2022-2266 Tract/Parcel Map No. Lot 17 & Portion of Lot 19, Block 4, Section 5 of Balboa Island Building Permit No. TBD CUP, SUP, and/or APN (Specify Lot Numbers if Portions of Tract) 050-184-17 This Water Quality Management Plan (WQMP) has been prepared for Joseph Cefalia by Toal Engineering, Inc. The WQMP is intended to comply with the requirements of the local NPDES Stormwater Program requiring the preparation of the plan. The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this plan and will ensure that this plan is amended as appropriate to reflect up-to-date conditions on the site consistent with the current Orange County Drainage Area Management Plan (DAMP) and the intent of the non-point source NPDES Permit for Waste Discharge Requirements for the County of Orange, Orange County Flood Control District and the incorporated Cities of Orange County within the San Diego Region (South Orange County).. Once the undersigned transfers its interest in the property, its successors-in-interest shall bear the aforementioned responsibility to implement and amend the WQMP. An appropriate number of approved and signed copies of this document shall be available on the subject site in perpetuity. Owner: Title Garrett and Heather bland Company - Address 14975 Corona Del Mar Pacific Palisades, CA 90272 Email gbland1986@gmail.com Telephone # (310) 488-3778 Signature Date Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Table of Contents Contents Page No. Section I Discretionary Permit(s) and ............................................. 3 Water Quality Conditions ................................................................... 3 Section II Project Description ...................................................... 4 II.1 Project Description .............................................................. 4 II.2 Potential Stormwater Pollutants ............................................ 5 II.3 Hydrologic Conditions of Concern ......................................... 6 II.4 Post Development Drainage Characteristics ........................... 6 II.5 Property Ownership/Management ......................................... 6 Section III Site Description ........................................................... 7 III.1 Physical Setting ................................................................... 7 III.2 Site Characteristics .............................................................. 8 III.3 Watershed Description ........................................................ 10 Section IV Best Management Practices (BMPs) ......................... 11 IV. 1 Project Performance Criteria ................................................ 11 IV.2 Site Design And Drainage Plan ........................................... 13 IV.3 BMP Selection And Project Conformance Analysis .................. 14 IV.4 Alternative Compliance Plan (If Applicable) ........................... 25 Section V Inspection/Maintenance Responsibility for BMPs ......... 30 Section VI Site Plan and Drainage Plan ...................................... 32 VI.1 Site Plan And Drainage Plan ................................................ 32 VI.2 Electronic Data Submittal .................................................... 32 Section VII Educational Materials ................................................ 35 Attachments Attachment A . .........................................................................................BMP Fact Sheets Attachment B . ................................................................................. Educational Materials Attachment C …………………………………………….….……. Soils Reports Recommendation Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section I Page 3 Section I Discretionary Permit(s) and Water Quality Conditions Project Infomation Permit/Application No. TBD Tract/Parcel Map No. Lot 17 & Portion of Lot 19, Block 4, Section 5 of Balboa Island Additional Information/ Comments: Water Quality Conditions Water Quality Conditions (list verbatim) None. Watershed-Based Plan Conditions Provide applicable conditions from watershed -based plans including TMDLS. TMDLs for Lower Newport Bay: Nutrients (1998) Toxics (2002) Fecal Coliform (1999) Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section II Page 4 Section II Project Description II.1 Project Description Description of Proposed Project Development Category (Verbatim from WQMP): 5.Impervious surface of 2,500 square feet or more located within, directly adjacent to (within 200 feet), or discharging directly into receiving waters within Environmentally Sensitive Areas (ESAs). Project Area (ft2): 2,556 Number of Dwelling Units: 1 SIC Code: n/a Narrative Project Description: The project consists of the following: (1) demolition of the existing residence and associated hardscape, (2) construction of a new custom single-family residence and appurtenant hardscape, landscape, and drainage improvements. Project Area Pervious Impervious Area (sf) Percentage Area (sf) Percentage Pre-Project Conditions 0 0 2,556 100 Post-Project Conditions 0 0 2,556 100 Drainage Patterns/Connections See Section III.2. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section II Page 5 II.2 Potential Stormwater Pollutants The following table lists the expected stormwater pollutants based on land uses and site activities per Table 2.1 of the Technical Guidance Document for the Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans (TGD). Pollutants of Concern Pollutant Circle One: E=Expected to be of concern N=Not Expected to be of concern Additional Information and Comments Suspended-Solid / Sediment ◇E N Nutrients ◇E N Heavy Metals E ◇N Pathogens (Bacteria/Virus) ◇E N Pesticides ◇E N Oil and Grease ◇E N Toxic Organic Compounds E ◇N Trash and Debris ◇E N Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section II Page 6 II.3 Hydrologic Conditions of Concern Hydrologic Conditions of Concern (HCOCs) do not exist for this project since site runoff is conveyed in a storm drain system and discharged directly into Newport Bay. II.4 Post Development Drainage Characteristics Post-project drainage patterns will be substantially the same as pre-project drainage patterns. The Runoff will be collected via concrete swales and drain inlets, treated through filtration devices and discharged Jade Avenue. Jade Avenue conveys surface flows via concrete swale to the gutter of park avenue which is conveyed into a catch basin at the end of Park Avenue. Stormwater treatment devices are discussed later in this report II.5 Property Ownership/Management This property is privately owned by: GARRETT AND HEATHER BLAND 14975 Corona Del Mar Pacific Palisades, CA 90272 Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section III Page 7 Section III Site Description III.1 Physical Setting Planning Area/ Community Name N/A Location/Address 125 East Bayfront, Newport Beach, California Project Area Description The subject property is a rectangular shaped lot located at 125 East Bayfront in the City of Newport Beach, County of Orange, California. Lot is bound by Jade Avenue to the east, by East Bayfront boardwalk to the west, and by similar single-family dwellings to the north and south. Land Use RSD-A: Single Unit Residential Detached (0.0-5.9 DU/AC) Zoning RLD-9: Single Unit Residential Acreage Property: 2,556 s.f. (0.058 acres) Project: 2,556 s.f. (0.058 acres) Predominant Soil Type Per Watershed Infiltration & Hydromodification Management Plan (WIHMP) GIS website, the project is underlain by soil Type D. http://ocpw.maps.arcgis.com/apps/PublicGallery Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section III Page 8 III.2 Site Characteristics Precipitation Zone 0.7-in (TGD Fig XVI-1) Topography The subject property is a relatively flat residential lot. Elevations on the developed portion of the site range from a maximum of about 7.3- feet to a minimum of about 6.7-feet. Drainage Patterns/Connections Under existing conditions, the westerly half of the property’s runoff surface flows to Jade Avenue. Jade Avenue conveys this runoff via concrete swale to the gutter of Park Avenue, which conveys the runoff into a catch basin at the end of Park Avenue. The Catch basin then discharges water via drain pipe into Newport Bay. The easterly half of the property’s runoff sheet flows to the East Bayfront boardwalk at the rear of the property. The boardwalk conveys runoff north via surface flow to the catch basin at the end of Park Avenue which discharges into Newport Bay and eventually the Pacific Ocean. Soil Type, Geology, and Infiltration Properties Per the Soils report prepared by Albus and Associates, Inc., “Based on review of the geologic literature, previous geotechnical reports, and site exploration, the site is underlain by artificial fills and estuarine deposits. Artificial fill was encountered to the full depth of our boring (10 feet below ground surface). We estimate the artificial fills extend to a depth of about 12 feet based on data collected at 225 E. Bay Front (EGA 2017). The fill materials are generally comprised of interlayered silty sands and fine to medium, poorly-graded sands with occasional sea shells. These materials are typically medium dense and moist near the surface but become wet near a depth of 4 feet. Estuarine deposits underly the artificial fills and extend to a depth of about 40 feet based on data contained in the report by EGA (2017). These materials generally consist of interlayered silty sands and poorly-graded sands that are medium dense but become dense below a depth of about 20 feet. Below a depth of 40 feet, the underlying materials become a stiff silty clay and clay as suggested by the nearby CPT sounding by EGA. These materials may be an upper weathered section of the Capistrano Formation bedrock that is generally comprised of siltstone or the Monterey Formation bedrock that is interbedded siltstone and claystone. Detailed descriptions of the subsurface conditions encountered within the site and nearby surrounding area are provided the exploration logs and CPT soundings contained in Appendices A and B.” Hydrogeologic (Groundwater) Conditions Per the soils report by Albus and Associates, Inc., “groundwater was encountered in our boring at a depth of 4 below ground surface. The depth to ground water is significantly influenced by the water levels Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section III Page 9 in the nearby channel. Based on our previous experience in the general area, groundwater is likely to vary by 1 to 2 feet due to tidal fluctuations. Our boring was drilled at about the time of high tide (6.07 ft) and therefore, the depth to groundwater of 4 feet that we encountered is very near the shallowest expected depth.” Geotechnical Conditions (relevant to infiltration) Per letter by soils engineer, “Given the very shallow groundwater conditions and presence of fill soils down to groundwater, infiltration of storm water is not feasible due to limitations set by the LID manual for the Santa Ana Regional Water Quality Control Board. Infiltration in a basin must be at least 5 feet above seasonally high ground water. We encountered water at 4 feet. The LID does not allow infiltration into manmade fills and the site is underlain by fills to near 12 feet in depth. Both of these conditions preclude infiltration.” Off-Site Drainage The project site does not receive run-on from adjacent properties. Utility and Infrastructure Information Public and private utilities are already in place for this property. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section III Page 10 III.3 Watershed Description Receiving Waters Lower Newport Bay 303(d) Listed Impairments Chlordane, Copper, DDT, Indicator Bacteria, Nutrients, PCBs, Pesticides, Sediment Toxicity Applicable TMDLs Sediment, Nutrients, Toxics, Fecal Coliform Pollutants of Concern for the Project Primary Pollutants of Concern: Chlordane, Copper, DDT, Indicator Bacteria, Nutrients, PCBs, Pesticides, Sediment Toxicity. Other Pollutants of Concern: None. Environmentally Sensitive and Special Biological Significant Areas Lower Newport Bay. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 11 Section IV Best Management Practices (BMPs) IV. 1 Project Performance Criteria Project Performance Criteria If HCOC exists, list applicable hydromodification control performance criteria (MWQMP Appendix C) Per Section II.3 of this report, HCOCs do not exist for the proposed project. List applicable LID performance criteria (Section 7.II-2.4.3 from MWQMP) • Priority Projects must infiltrate, harvest and use, evapotranspire, or biotreat/biofilter, the 85th percentile, 24-hour storm event (Design Capture Volume). • A properly designed biotreatment system may only be considered if infiltration, harvest and use, and evapotranspiration (ET) cannot be feasibly implemented for the full design capture volume. In this case, infiltration, harvest and use, and ET practices must be implemented to the greatest extent feasible and biotreatment may be provided for the remaining design capture volume. Calculate LID DCV for Project. Simple Method per TGD III.1.1. 𝐶𝐶𝑉=𝐶 × 𝑐 × 𝐴 imp = 1.0 𝐶= (0.75 × 𝑖𝑚𝑝+0.15)=0.75 × 1.0 +0.15 =0.90 𝑐= 0.65 𝑖𝑚. 𝐴= 2,556 𝑠𝑝.𝑓𝑠. 𝐶𝐶𝑉=0.90 x 0.65 𝑖𝑚.x 2,556 𝑠.𝑓.x (1 𝑓𝑠. 12 𝑖𝑚.)=125 𝑐𝑓 Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 12 Worksheet B: Simple Design Capture Volume Sizing Method Step 1: Determine the design capture storm depth used for calculating volume 1 Enter design capture storm depth from Figure III.1, d (inches) d= 0.65 inches 2 Enter the effect of provided HSCs, dHSC (inches) (Worksheet A) dHSC= 0.00 inches 3 Calculate the remainder of the design capture storm depth, dremainder (inches) (Line 1 – Line 2) dremainder= 0.65 inches Step 2: Calculate the DCV 1 Enter Project area tributary to BMP (s), A (acres) A= 0.058 acres 2 Enter Project Imperviousness, imp (unitless) imp= 1.0 3 Calculate runoff coefficient, C= (0.75 x imp) + 0.15 C= 0.90 4 Calculate runoff volume, Vdesign= (C x dremainder x A x 43560 x (1/12)) Vdesign= 123 cu-ft Step 3: Design BMPs to ensure full retention of the DCV Step 3a: Determine design infiltration rate 1 Enter measured infiltration rate, Kmeasured (in/hr) (Appendix VII) Kmeasured= N/A In/hr 2 Enter combined safety factor from Worksheet H, Sfinal (unitless) Sfinal= N/A 3 Calculate design infiltration rate, Kdesign = Kmeasured / Sfinal Kdesign= N/A In/hr Step 3b: Determine minimum BMP footprint 4 Enter drawdown time, T (max 48 hours) T= N/A Hours 5 Calculate max retention depth that can be drawn down within the drawdown time (feet), Dmax = Kdesign x T x (1/12) Dmax= N/A feet 6 Calculate minimum area required for BMP (sq-ft), Amin = Vdesign/ dmax Amin= N/A sq-ft Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 13 IV.2 Site Design And Drainage Plan Overview The ultimate plan of development for the proposed project is shown on the WQMP Site Plan in Section VI of this report. The project Precise Grading Plan shows the proposed grading, site improvements, and retaining walls necessary for construction of a single-family residence. Site Design Practices The project incorporates Site Design practices as follows: • Preserve Existing Drainage Patterns and Time of Concentration – The ultimate points of discharge are the same for the pre- and post-project conditions. Time of concentration will be similar, since pre-and post-project flow path lengths will be similar. Drainage Management Areas (DMAs) The site has two drainage management areas. Drainage from DMA-1 on the northerly half of the side collects runoff via channel drains and inlets and conveys that storm water via a 4” drain pipe to a trench drain filter at the north westerly corner of the site for treatment. The treated stormwater is then discharged through an outlet at the bottom step at the corner of the property and sheet flows into the concrete swale of Jade Avenue. Jade Avenue conveys surface runoff to the westerly gutter of Park Avnue which conveys the stormwater to a channel drain at the end of Park Avenue. This channel drain discharges directly to Newport Bay and ultimately the Pacific Ocean. Drainage from DMA-2 similarly captures stormwater on the southerly half of the property, and then similarly treats and discharges stormwater to Jade Avenue. Any excess runoff on the westerly half of the property will be able to sheet flow to Jade Avenue via concrete swale, and any excess runoff on the easterly portion of the property will be able to sheet flow onto the East Bayfront boardwalk. Runoff onto East Bayfront Boardwalk flows northerly to catch Basins at the End of Park Avenue where it discharges into Newport Bay and ultimately the Pacific Ocean. DMA-1 DMA-2 Total Area (ac) 0.023 0.021 Total Area (sf) 1,173 1,173 Impervious Area (sf) 1,173 1,173 Pervious Area (sf) 0 0 imp 1.0 1.0 C 0.90 0.90 d (in) 0.65 0.65 DCV (cf) 57 57 Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 14 IV.3 BMP Selection And Project Conformance Analysis Each sub-section below documents that the proposed design features conform to the applicable project performance criteria via check boxes, tables, calculations, narratives, and/or references to worksheets. IV.3.1 Hydrologic Source Controls The Hydrologic Source Controls to be used for this project are indicated in the table below. Implementation of said controls is discussed in the text that follows. Name Included? Localized on-lot infiltration Impervious area dispersion (e.g. roof top disconnection) Street trees (canopy interception) Residential rain barrels (not actively managed) Green roofs/Brown roofs Blue roofs Impervious area reduction (e.g. permeable pavers, site design) Other: Hydrologic Source Controls have not been used due to space constraints, including landscape area size and proximity to structure foundations. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 15 IV.3.2 Infiltration BMPs Infiltration BMPs to be used for this project are indicated in the table below. Implementation of said controls is discussed in the text that follows. Name Included? Bioretention without underdrains Rain gardens Porous landscaping Infiltration planters Retention swales Infiltration trenches Infiltration basins Drywells Subsurface infiltration galleries French drains Permeable asphalt Permeable concrete Permeable concrete pavers Other: On-Site infiltration is not feasible per soils engineer’s recommendation. See letter attached in appendix. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 16 Table 2.7: Infiltration BMP Feasibility Worksheet Infeasibility Criteria Yes No 1 Would Infiltration BMPs pose significant risk for groundwater related concerns? Refer to Appendix VII (Worksheet I) for guidance on groundwater-related infiltration feasibility criteria. X Provide basis: Infiltration BMPs will not pose a significant risk to local groundwater. Groundwater in the vicinity of the project site is not used for drinking water. Pretreatment devices will mitigate entry of trash, sediment, and oil & grease into proposed infiltration BMPs. 2 Would Infiltration BMPs pose significant risk of increasing risk of geotechnical hazards that cannot be mitigated to an acceptable level? (Yes if the answer to any of the following questions is yes, as established by a geotechnical expert): • The BMP can only be located less than 50 feet away from slopes steeper than 15 percent • The BMP can only be located less than eight feet from building foundations or an alternative setback. • A study prepared by a geotechnical professional or an available watershed study substantiates that stormwater infiltration would potentially result in significantly increased risks of geotechnical hazards that cannot be mitigated to an acceptable level. X Provide basis: The site area is limited and the BMP can only be located less than eight feet from building foundations or an alternative setback. 3 Would infiltration of the DCV from drainage area violate downstream water rights? X Provide basis: There are no downstream water right holders since site drainage is conveyed via the city storm drain system directly to receiving waters (Lower Newport Bay). Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 17 Table 2.7: Infiltration BMP Feasibility Worksheet (continued) Partial Infeasibility Criteria Yes No 4 Is proposed infiltration facility located on HSG D soils or the site geotechnical investigation identifies presence of soil characteristics which support categorization as D soils? X Provide basis: Per Orange County Soils Study, the project is located in Soils Group D. 5 Is measured infiltration rate below proposed facility less than 0.3 inches per hour? This calculation shall be based on the methods described in Appendix VII. X Provide basis: The infiltration rate was not measured. 6 Would reduction of over predeveloped conditions cause impairments to downstream beneficial uses, such as change of seasonality of ephemeral washes or increased discharge of contaminated groundwater to surface waters? X Provide citation to applicable study and summarize findings relative to the amount of infiltration that is permissible: No downstream beneficial uses such as ephemeral washes or groundwater sources of drinking water are located downstream of the subject property. 7 Would an increase in infiltration over predeveloped conditions cause impairments to downstream beneficial uses, such as change of seasonality of ephemeral washes or increased discharge of contaminated groundwater to surface waters? X Provide citation to applicable study and summarize findings relative to the amount of infiltration that is permissible: No downstream beneficial uses such as ephemeral washes or groundwater sources of drinking water are located downstream of the subject property. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 18 Table 2.7: Infiltration BMP Feasibility Worksheet (continued) Infiltration Screening Results (check box corresponding to result): 8 Is there substantial evidence that infiltration from the project would result in a significant increase in I&I to the sanitary sewer that cannot be sufficiently mitigated? (See Appendix XVII) Provide narrative discussion and supporting evidence: No evidence of I&I has been provided by the local sewer agency (City of Newport Beach). No 9 If any answer from row 1-3 is yes: infiltration of any volume is not feasible within the DMA or equivalent. Provide basis: X 10 If any answer from row 4-8 is yes, infiltration is permissible but is not presumed to be feasible for the entire DCV. Criteria for designing biotreatment BMPs to achieve the maximum feasible infiltration and ET shall apply. Provide basis: 11 If all answers to rows 1 through 10 are no, infiltration of the full DCV is potentially feasible, BMPs must be designed to infiltrate the full DCV to the maximum extent practicable. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 19 IV.3.3 Evapotranspiration, Rainwater Harvesting BMPs Evapotranspiration and/or Rainwater Harvesting BMPs to be used for this project are indicated in the table below. Implementation of said controls is discussed in the text that follows. Name Included? All HSCs; See Section IV.3.1 Surface-based infiltration BMPs Other vegetated BMPs Above-ground cisterns and basins Underground detention Other: The project site does not have an irrigation demand large enough to justify partial capture for irrigation demand. See Worksheet J from Section X of the TGD on the following page. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 20 Worksheet J: Summary of Harvested Water Demand and Feasibility 1 What demands for harvested water exist in the tributary area (check all that apply): 2 Toilet and urinal flushing □ 3 Landscape irrigation □ 4 Other:_______________________________________________________ □ 5 What is the design capture storm depth? (Figure III.1) d 0.65 inches 6 What is the project size? A 0.0058 ac 7 What is the acreage of impervious area? IA 0.058 ac For projects with multiple types of demand (toilet flushing, irrigation demand, and/or other demand) 8 What is the minimum use required for partial capture? (Table X.6) gpd 9 What is the project estimated wet season total daily use (Section X.2)? gpd 10 Is partial capture potentially feasible? (Line 9 > Line 8?) For projects with only toilet flushing demand 11 What is the minimum TUTIA for partial capture? (Table X.7) 12 What is the project estimated TUTIA? 13 Is partial capture potentially feasible? (Line 12 > Line 11?) For projects with only irrigation demand 14 What is the minimum irrigation area required based on conservation landscape design? (Table X.8) 0.78 x 0.058 = 0.0452 ac 15 What is the proposed project irrigated area? (multiply conservation landscaping by 1; multiply active turf by 2) 0.000 ac 16 Is partial capture potentially feasible? (Line 15 > Line 14?) No Provide supporting assumptions and citations for controlling demand calculation: Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 21 IV.3.4 Biofiltration BMPs Biofiltration BMPs to be used for this project are indicated in the table below. Implementation of said controls is discussed in the text that follows. Name Included? Bioretention with underdrains Stormwater planter boxes with underdrains Proprietary vegetated biotreatment systems Other: The use of Biotreatment BMPs on the site would restrict the use of the development. Per XIV-74 of the TGD, Media filters may be used for drainage area with limited available surface area or where surface BMPs would restrict uses. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 22 IV.3.5 Hydromodification Control BMPs Hydromodification controls are not required for this project because Hydrologic Conditions of Concern do not exist for this project. See Section II.3. Hydromodification Control BMPs BMP Name BMP Description Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 23 IV.3.6 Non-structural Source Control BMPs Non-structural source control BMPs used for this project are described below. Non-Structural Source Control BMPs Identifier Name Check One If not applicable, state brief reason Included Not Applicable N1 Education for Property Owners, Tenants and Occupants N2 Activity Restrictions N3 Common Area Landscape Management No common areas present. N4 BMP Maintenance N5 Title 22 CCR Compliance (How development will comply) No hazardous waste. N6 Local Industrial Permit Compliance Not an industrial project. N7 Spill Contingency Plan No hazardous waste. N8 Underground Storage Tank Compliance No USTs on site. N9 Hazardous Materials Disclosure Compliance No hazardous waste. N10 Uniform Fire Code Implementation No hazardous waste. N11 Common Area Litter Control No common areas present. N12 Employee Training No employees. N13 Housekeeping of Loading Docks No loading docks exposed to storm water proposed. N14 Common Area Catch Basin Inspection No common areas present. N15 Street Sweeping Private Streets and Parking Lots No exterior parking areas. N16 Retail Gasoline Outlets None exist. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 24 IV.3.7 Structural Source Control BMPs Structural source control BMPs used for this project are described below. Structural Source Control BMPs Identifier Name Check One If not applicable, state brief reason Included Not Applicable S1 Provide storm drain system stenciling and signage Drain inlets on private property. S2 Design and construct outdoor material storage areas to reduce pollution introduction No outdoor MSAs. S3 Design and construct trash and waste storage areas to reduce pollution introduction S4 Use efficient irrigation systems & landscape design, water conservation, smart controllers, and source control S5 Protect slopes and channels and provide energy dissipation No proposed slopes or channels. Incorporate requirements applicable to individual priority project categories (from SDRWQCB NPDES Permit) S6 Dock areas None exist. S7 Maintenance bays None exist. S8 Vehicle wash areas None exist. S9 Outdoor processing areas None exist. S10 Equipment wash areas None exist. S11 Fueling areas None exist. S12 Hillside landscaping None exist. S13 Wash water control for food preparation areas None exist. S14 Community car wash racks None exist. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 25 IV.4 Alternative Compliance Plan (If Applicable) IV.4.1 Request of Waiver of LID BMPs Provide documentation of feasibility analysis if implementation of LID BMPs is technically infeasible. Refer to Section 7.II-3.1 in the Model WQMP. Calculate the amount of remaining obligation that must be met with alternative compliance (See TGD Appendix VI). IV.4.2 Water Quality Credits Determine if water quality credits are applicable for the project. Refer to Section 7.II-3.2 of the Model WQMP for description of credits and TGD Appendix VI for calculation methods for applying WQ credits. Description of Proposed Project Project Types that Qualify for Water Quality Credits (Select all that apply): Redevelopment projects that reduce the overall impervious footprint of the project site. Brownfield redevelopment, meaning redevelopment, expansion, or reuse of real property which may be complicated by the presence or potential presence of hazardous substances, pollutants or contaminants, and which have the potential to contribute to adverse ground or surface WQ if not redeveloped. Higher density development projects which include two distinct categories (credits can only be taken for one category): those with more than seven units per acre of development (lower credit allowance); vertical density developments, for example, those with a Floor to Area Ratio (FAR) of 2 or those having more than 18 units per acre (greater credit allowance). Mixed use development, such as a combination of residential, commercial, industrial, office, institutional, or other land uses which incorporate design principles that can demonstrate environmental benefits that would not be realized through single use projects (e.g. reduced vehicle trip traffic with the potential to reduce sources of water or air pollution). Transit-oriented developments, such as a mixed use residential or commercial area designed to maximize access to public transportation; similar to above criterion, but where the development center is within one half mile of a mass transit center (e.g. bus, rail, light rail or commuter train station). Such projects would not be able to take credit for both categories, but may have greater credit assigned Redevelopment projects in an established historic district, historic preservation area, or similar significant city area including core City Center areas (to be defined through mapping). Developments with dedication of undeveloped portions to parks, preservation areas and other pervious uses. Developments in a city center area. Developments in historic districts or historic preservation areas. Live-work developments, a variety of developments designed to support residential and vocational needs together – similar to criteria to mixed use development; would not be able to take credit for both categories. In-fill projects, the conversion of empty lots and other underused spaces into more beneficially used spaces, such as residential or commercial areas. Calculation of Water Quality Credits (if applicable) This project does not qualify for the water quality credits listed above. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 26 IV.4.3 Treatment Control BMPs Treatment Control BMPs BMP Name BMP Description PRE-2 Trench Drain filter insert Oldcastle Precast Flogard +Plus Trench Drain Filter(Model FG-TDOF8) for removal of gross solids, trach and debris, and petroleum hydrocarbons. Used for filtration of roof and hardscape runoff prior to discharge. Use and Location Inlet filtration devices will be used as treatment. Locations of proposed treatment control BMPs are shown on the BMP Exhibit in Section VI. Performance See Specification sheets in Attachment D. Sizing See Worksheet D (Capture Efficiency Method for Flow-Based BMPs) for pretreatment device capacity calculations at the end of this section. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 27 Worksheet D: Capture Efficiency Method for Flow-Based BMPs Step 1: Determine the design capture storm depth used for calculating volume 1 Enter the time of concentration, Tc (min) (See Appendix IV.2) Tc= 5 2 Using Figure III.4, determine the design intensity at which the estimated time of concentration (Tc) achieves 80% capture efficiency, I1 I1= 0.26 in/hr 3 Enter the effect depth of provided HSCs upstream, dHSC (inches) (Worksheet A) dHSC= 0.00 inches 4 Enter capture efficiency corresponding to dHSC, Y2 (Worksheet A) Y2= 0 % 5 Using Figure III.4, determine the design intensity at which the time of concentration (Tc) achieves the upstream capture efficiency(Y2), I2 I2= 0.00 6 Determine the design intensity that must be provided by BMP, Idesign= I1-I2 Idesign= 0.26 Step 2: Calculate the design flowrate 1 Enter Project area tributary to BMP (s), A (acres) A= 0 0.058 acres 2 Enter Project Imperviousness, imp (unitless) imp= . 1.0 3 Calculate runoff coefficient, C= (0.75 x imp) + 0.15 C= 0 0.90 4 Calculate design flowrate, Qdesign= (C x idesign x A) Qdesign= 0 0.013 cfs Supporting Calculations The design flowrate for the lot that is using the filter insert is 0.021 The provided 5’ of Oldcastle Precast Flogard +Plus trench drain filter Model FG-TDOF8 provides 0.5 cfs of filtered flow……OK Provide time of concentration assumptions: Tc of 5-minutes is the minimum allowed and provides the most conservative design. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 28 Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section IV Page 29 IV.4.4 Regional/Sub-Regional LID BMPs This project’s jurisdiction does not have Regional/Sub-Regional LID BMPs. Regional/Sub-Regional LID BMPs IV.4.5 Other Alternative Compliance Measures This project will not make use of other alternative compliance measures. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section V Page 30 Section V Inspection/Maintenance Responsibility for BMPs Fill out information in table below. Prepare and attach an Operation and Maintenance Plan. Identify the mechanism through which BMPs will be maintained. Inspection and maintenance records must be kept for a minimum of five years for inspection by the regulatory agencies. Refer to Section 7.II-4.0 in the Model WQMP. BMP Inspection/Maintenance BMP Reponsible Party(s) Inspection/ Maintenance Activities Required Minimum Frequency of Activities PRE-2 Filter Insert (Pre- Treatment) Owner via maintenance contractors • Filter Insert Replacement/Rotation • Once a year. Refer to Manufacturer’s O&M plan on pages 36-39 for details. • Remove Sediment and debris. • Three times per year and after storm events. Refer to Manufacturer’s O&M plan on pages 36-39 for details. N1 – Education for Property Owners Owner Owner must understand purpose of all BMPs and how they work. The contractor who installs the BMP shall educate the owner and the owner shall share the information with any maintenance personnel. Additionally, the owner shall keep a copy of this WQMP, as well as the Operations and Maintenance Plan. As required Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section V Page 31 N2 – Activity Restrictions Owner or contracted maintenance personnel Use dry cleanup methods.. Hazardous items shall be disposed of properly. As required. N4 – BMP Maintenance Owner or contracted maintenance personnel Visual Inspection, perform more thorough inspection if ponding water sits for more than 48 hours. Twice yearly and immediately following each storm event. S3 – Trash & Waste Storage Area Owner or contracted maintenance personnel Keep trash storage areas clean and orderly. Weekly S4 – Efficient Irrigation Owner or contracted maintenance personnel Ensure that sprinklers are working properly and minimize unnecessary irrigation. Weekly Inspection and Maintenance Guide FLOGARD® LOPRO TRENCH DRAIN FILTER DRAIN A G E P R OTECTION SY ST E M S A division of Oldcastle Infrastructure SCOPE: Federal, State and Local Clean Water Act regulations and those of insurance carriers require that stormwater filtration systems be maintained and serviced on a recurring basis. The intent of the regulations is to ensure that the systems, on a continuing basis, efficiently remove pollutants from stormwater runoff thereby preventing pollution of the nation’s water resources. These specifications apply to the FloGard® LoPro Trench Drain Filter. RECOMMENDED FREQUENCY OF SERVICE: Drainage Protection Systems (DPS) recommends that installed FloGard LoPro Trench Drain Filters be serviced on a recurring basis. Ultimately, the frequency depends on the amount of runoff, pollutant loading and interference from debris (leaves, vegetation, cans, paper, etc.); however, it is recommended that each installation be serviced a minimum of three times per year, with a change of filter medium once per year. DPS technicians are available to do an on-site evaluation, upon request. RECOMMENDED TIMING OF SERVICE: DPS guidelines for the timing of service are as follows: 1. For areas with a definite rainy season: Prior to, during and following the rainy season. 2. For areas subject to year-round rainfall: On a recurring basis (at least three times per year).3. For areas with winter snow and summer rain: Prior to and just after the snow season and during the summer rain season. 4. For installed devices not subject to the elements (washracks, parking garages, etc.): On a recurring basis (no less than three times per year). SERVICE PROCEDURES: 1. The trench drain grate(s) shall be removed and set to one side. 2. The service shall commence with collection and removal of sediment and debris (litter, leaves, papers, cans, etc.). 3. The trench drain shall be visually inspected for defects and possible illegal dumping. If illegal dumping has occurred, the proper authorities and property owner representative shall be notified as soon as practicable. 4. Using an industrial vacuum, the collected materials shall be removed from the filter liner. (Note: DPS uses a truck-mounted vacuum for servicing FloGard LoPro Trench Drain Filters.) 5. When all of the collected materials have been removed, the filter assembly shall be removed from the drainage inlet. The outer filter liner shall be removed from the filter assembly and filter medium pouches shall be removed by unsnapping the tether from the interior ring and sent to one side. The filter liner, PVC body and fittings shall be inspected for continued serviceability. Minor damage or defects found shall be corrected on the spot and a notation made on the Maintenance Record. More extensive deficiencies that affect the efficiency of the filter (torn liner, etc.), if approved by the customer representative, will be corrected and a quote submitted to the representative along with the Maintenance Record. 6. The filter liner and filter medium pouches shall be inspected for defects and continued serviceability and replaced as necessary and the pouch tethers re-attached to the PVC body interior ring. 7. The grate(s) shall be replaced. 2 INSPECTION AND MAINTENANCE GUIDE 3 REPLACEMENT AND DISPOSAL OF EXPOSED FILTER MEDIUM AND COLLECTED DEBRIS The frequency of filter medium exchange will be in accordance with the existing DPS-Customer Maintenance Contract. DPS recommends that the medium be changed at least once per year. During the appropriate service, or if so determined by the service technician during a non-scheduled service, the filter medium pouches will be replaced. Once the exposed pouches and debris have been removed, DPS has possession and must dispose of it in accordance with local, state and federal agency requirements. DPS also has the capability of servicing all manner of storm drain filters, catch basin inserts and catch basins without inserts, underground oil/water separators, stormwater interceptors and other such devices. All DPS personnel are highly qualified technicians and are confined-space trained and certified. Call us at (888) 950-8826 for further information and assistance. Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section VI Page 32 Section VI Site Plan and Drainage Plan VI.1 Site Plan And Drainage Plan Include a site plan and drainage plan sheet set containing the following minimum information: • Project location • Site boundary • Land uses and land covers, as applicable • Suitability/feasibility constraints • Structural BMP locations • Drainage delineations and flow information • Drainage connections • BMP details VI.2 Electronic Data Submittal The minimum requirement is to provide submittal of PDF exhibits in addition to hard copies. Format must not require specialized software to open. EA S T B A Y F R O N T CRAWLSPACE F.F. ABOVE=9.00 CRAWLSPACE T/SLAB=VARIES GARAGE F.F.=VARIES WQMP LEGEND PROPOSED BUILDING PROPOSED LANDSCAPE PROPOSED HARDSCAPE RUNOFF FLOW DIRECTION DETAIL PRE TREATMENT DEVICE CHANNEL DRAIN W/ FILTER INSERT DETAIL CONCRETE CHANNEL DRAIN DRAINAGE BOUNDARY 1 3 9 A v e n i d a N a v a r r o S a n C le m e n t e , C A 9 2 6 7 2 9 4 9 .4 9 2 .8 5 8 6 w w w.t o ale n g i n ee r i n g .co m C I V I L E N G I N E E R I N G L A N D S U R V E Y I N G STO RM WA TE R Q UA LI TY BMP DOWNSPOUT CONNECTIONS Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section VI Page 33 Figure VI.1. Vicinity Map. Source: maps.google.com SITE Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section VI Page 34 Figure VI.2. Aerial Image. Source: maps.google.com SITE Water Quality Management Plan (WQMP) Garrett and Heather Bland – 125 East Bayfront, Newport Beach, California GARRETT AND HEATHER BLAND Section VII Page 35 Section VII Educational Materials Refer to the Orange County Stormwater Program (ocwatersheds.com) for a library of materials available. For the copy submitted to the Permittee, only attach the educational materials specifically applicable to the project. Other materials specific to the project may be included as well and must be attached. Education Materials Residential Material (http://www.ocwatersheds.com) Check If Applicable Business Material (http://www.ocwatersheds.com) Check If Applicable The Ocean Begins at Your Front Door Tips for the Automotive Industry Tips for Car Wash Fund-raisers Tips for Using Concrete and Mortar Tips for the Home Mechanic Tips for the Food Service Industry Homeowners Guide for Sustainable Water Use Proper Maintenance Practices for Your Business Household Tips Compliance BMPs for Mobile Businesses Proper Disposal of Household Hazardous Waste Other Material Check If Attached Recycle at Your Local Used Oil Collection Center (North County) Recycle at Your Local Used Oil Collection Center (Central County) Recycle at Your Local Used Oil Collection Center (South County) Tips for Maintaining a Septic Tank System Responsible Pest Control Sewer Spill Tips for the Home Improvement Projects Tips for Horse Care Tips for Landscaping and Gardening Tips for Pet Care Tips for Projects Using Paint ATTACHMENT A TECHNICAL GUIDANCE DOCUMENT APPENDICES XIV-74 December 20, 2013 TRT-2: Cartridge Media Filter Cartridge media filters (CMFs) are manufactured devices that consist of a series of modular filters packed with engineered media that can be contained in a catch basin, manhole, or vault that provide treatment through filtration and sedimentation. The manhole or vault may be divided into multiple chambers where the first chamber acts as a pre- settling basin for removal of coarse sediment while another chamber acts as the filter bay and houses the filter cartridges. A variety of media types are available from various manufacturers which can target pollutants of concern. Feasibility Screening Considerations x Not applicable Opportunity Criteria x Intended for use when retention and biotreatment options are infeasible. x Recommended for drainage area with limited available surface area or where surface BMPs would restrict uses. x For drainage areas with significant areas of non-stabilized soil, permanent soil stablization must be achieved before before cartridge media filters are installed and put on line to minimize risk of clogging. x Depending on the number of cartridges, maintenance events can have long durations. Care should be exercised in siting these facilities so that maintenance events will not significantly disrupt businesses or traffic. OC-Specific Design Criteria and Considerations □ Cartridge media filter BMP vendors should be consulted regarding design and specifications. □ Filter media should be selected to target pollutants of concern. A combination of media may be appropriate to remove a variety of pollutants. □ If CMF are integrated with a vault for equalization, the system should be designed to completely drain the vault within 96 hours of storm event or otherwise protect against standing water and mosquito breeding concerns. Computing Sizing Criteria for Cartridge Media Filters The required design flowrate should be calculated based on the Capture Efficiency Method for Flow- based BMPs (See Appendix III.3.3). Additional References for Design Guidance x Los Angeles County Stormwater BMP Design and Maintenance Manual, Chapter 9: http://dpw.lacounty.gov/DES/design_manuals/StormwaterBMPDesignandMaintenance.pdf Cartridge Media Filter Source: Contech Stormwater Solution, Inc. Also known as: ¾Manufactured Media Filters TECHNICAL GUIDANCE DOCUMENT APPENDICES XIV-75 December 20, 2013 x SMC LID Manual: http://www.lowimpactdevelopment.org/guest75/pub/All_Projects/SoCal_LID_Manual/SoCalL ID_Manual_FINAL_040910.pdf x Western Washington Stormwater Management Manual, Volume V, Chapter 12: http://www.ecy.wa.gov/pubs/0510033.pdf ATTACHMENT B ATTACHMENT C 1011 N. Armando Street, Anaheim, CA 92806-2606 (714) 630-1626 October 29, 2021 J.N.: 3010.00 Garrett & Heather Bland 14975 Corona Del Mar Pacific Palisades, CA 90272 Subject: Geotechnical Investigation, Proposed Single-Family Residence, 125 East Bay Front, Newport Beach, California Dear Mr. & Mrs. Bland, Pursuant to your request, Albus & Associates, Inc. is pleased to present to you our geotechnical investigation report for the subject development. This report presents the results of our field investigation, laboratory testing, engineering analyses, as well as our preliminary geotechnical recommendations for design and construction of the subject development. We appreciate this opportunity to be of service to you. If you have any questions regarding the contents of this report, please do not hesitate to call this office. Sincerely yours, ALBUS & ASSOCIATES, INC. David E. Albus Principal Engineer Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page i TABLE OF CONTENTS ALBUS & ASSOCIATES, INC. 1.0 INTRODUCTION..................................................................................................................... 1 1.1 PURPOSE AND SCOPE ........................................................................................................ 1 1.2 SITE LOCATION AND DESCRIPTION ............................................................................... 1 1.3 PROPOSED DEVELOPMENT .............................................................................................. 1 1.4 RESEARCH ............................................................................................................................ 2 2.0 INVESTIGATION .................................................................................................................... 3 2.1 SUBSURFACE INVESTIGATION........................................................................................ 3 2.2 LABORATORY TESTING .................................................................................................... 3 3.0 GEOLOGIC CONDITIONS.................................................................................................... 3 3.1 GEOLOGIC SETTING ........................................................................................................... 3 3.2 GEOLOGIC UNITS ................................................................................................................ 4 3.3 GROUNDWATER .................................................................................................................. 4 3.4 FAULTING ............................................................................................................................. 4 4.0 ANALYSES ............................................................................................................................... 5 4.1 SEISMICITY ........................................................................................................................... 5 4.2 STATIC SETTLEMENT ........................................................................................................ 6 5.0 CONCLUSIONS ....................................................................................................................... 7 5.1 FEASIBILITY OF PROPOSED DEVELOPMENT ............................................................... 7 5.2 GEOLOGIC HAZARDS ......................................................................................................... 7 5.2.1 Ground Rupture ................................................................................................................ 7 5.2.2 Ground Shaking ................................................................................................................ 7 5.2.3 Liquefaction ...................................................................................................................... 7 5.3 STATIC SETTLEMENT ........................................................................................................ 8 5.4 EXCAVATION AND MATERIAL CHARACTERISTICS .................................................. 8 5.5 SHRINKAGE AND SUBSIDENCE ....................................................................................... 8 6.0 RECOMMENDATIONS .......................................................................................................... 9 6.1 EARTHWORK ........................................................................................................................ 9 6.1.1 General Earthwork and Grading Specifications ............................................................... 9 6.1.2 Pre-Grade Meeting and Geotechnical Observation .......................................................... 9 6.1.3 Site Clearing...................................................................................................................... 9 6.1.4 Ground Preparation ........................................................................................................... 9 6.1.5 Fill Placement ................................................................................................................. 10 6.1.6 Import Materials .............................................................................................................. 10 6.1.7 Temporary Excavations .................................................................................................. 10 6.1.8 Shoring ............................................................................................................................ 10 6.1.9 Dewatering ...................................................................................................................... 11 6.2 SEISMIC DESIGN PARAMETERS .................................................................................... 11 6.2.1 Mapped Seismic Design Parameters ............................................................................... 11 6.2.2 Site-Specific Seismic Design Parameters ....................................................................... 12 6.3 CONVENTIONAL FOUNDATION DESIGN ..................................................................... 12 6.3.1 General ............................................................................................................................ 12 6.3.2 Soil Expansion ................................................................................................................ 13 6.3.3 Settlement Considerations .............................................................................................. 13 6.3.4 Allowable Bearing Value ................................................................................................ 13 6.3.5 Lateral Resistance ........................................................................................................... 13 Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page ii TABLE OF CONTENTS REPORT ALBUS & ASSOCIATES, INC. 6.3.6 Footing and Slab on Grade ............................................................................................. 14 6.3.7 Footing Observations ...................................................................................................... 15 6.4 MAT SLAB ........................................................................................................................... 15 6.5 RETAINING AND SCREENING WALLS.......................................................................... 16 6.5.1 General ............................................................................................................................ 16 6.5.2 Allowable Bearing Value and Lateral Resistance .......................................................... 16 6.5.3 Active Earth Pressures .................................................................................................... 16 6.5.4 Drainage and Moisture-Proofing .................................................................................... 16 6.5.5 Footing Reinforcement ................................................................................................... 18 6.5.6 Footing Observations ...................................................................................................... 18 6.5.7 Retaining Wall Backfill .................................................................................................. 18 6.5.8 Wall Jointing ................................................................................................................... 18 6.6 CONCRETE MIX DESIGN .................................................................................................. 18 6.7 EXTERIOR FLATWORK .................................................................................................... 19 6.8 POST GRADING CONSIDERATIONS .............................................................................. 19 6.8.1 Site Drainage and Irrigation ............................................................................................ 19 6.8.2 Utility Trenches .............................................................................................................. 19 6.9 PLAN REVIEW AND CONSTRUCTION SERVICES ....................................................... 20 7.0 LIMITATIONS ....................................................................................................................... 20 REFERENCES .................................................................................................................................. 22 FIGURES AND PLATES Figure 1 – Site Location Map Plate 1 – Geotechnical Map APPENDICES APPENDIX A - EXPLORATION LOGS AND LAB- BY EGA APPENDIX B - EXPLORATION LOG BY ALBUS APPENDIX C- LIQUEFACTION CALCS BY EGA Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 1 ALBUS & ASSOCIATES, INC. 1.0 INTRODUCTION 1.1 PURPOSE AND SCOPE The purposes of our preliminary geotechnical investigation were to evaluate geotechnical conditions within the project area and to provide conclusions and recommendations relevant to the design and construction of the proposed improvements at the subject site. The scope of this investigation included the following: Review of previous geotechnical reports, published geologic and seismic data for the site and surrounding area Exploratory drilling and soil sampling Laboratory testing of selected soil samples Engineering analyses of data obtained from our review, exploration, and laboratory testing Evaluation of site seismicity and settlement potential Preparation of this report 1.2 SITE LOCATION AND DESCRIPTION The site is located within the address of 125 East Bay Front within the city of Newport Beach, California. The site is bordered by residential properties to the north and south, Jade Ave to the west, and the Newport Harbor/East Bay Front to the east. The location of the site and its relationship to the surrounding areas is shown in Figure 1, Site Location Map. The project site and overall property are relatively flat with elevations ranging from 11 to 12 feet above mean sea level (based on Google Earth). The site appears to drain generally towards Jade Ave on the west and towards East Bay Front on the east as sheet flow. The property is currently occupied by an existing two-story house. The house occupies the middle of the property with the garage entrance accessed from Jade Ave on the west. The east portion of the property contains a patio space with concrete hardscaping which extends along the north and south sides of the house and up to East Bay Front on the east. Vegetation of the site consists of grass, shrubs and a moderate sized tree. 1.3 PROPOSED DEVELOPMENT We understand the proposed site development will consist of the complete teardown of the existing house and construction of a new 3-story single-family residential house. The development is planned with a wood-framed residential building and may include one basement level. No structural plans were available for our review at this time. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 2 ALBUS & ASSOCIATES, INC. © 2021 Google Earth FIGURE 1 - SITE LOCATION MAP Proposed Single-Family Residence, 125 East Bay Front, Newport Beach, California NOT TO SCALE 1.4 RESEARCH Our review of historical aerial photos indicates the site was occupied by a single family home by 1938. The home is still seen in a photo from 1952 but is gone in 1953. In a photo from 1963, the current home can be seen occupying the property. A geologic map for the area (Morton, PK et al. 1973) indicates the general area is underlain by alluvial and colluvial materials (Qac) mostly consisting of loosely consolidated gravel, sand, and silt of stream channels. A more recent geologic map for the area (Morton, D.M., and Miller, F.K., 2006), indicates the site is underlain by estuarine deposits (Qes) consisting of unconsolidated sand, silt, and clay that contains variable amounts of organic matter. The site is not located within a Alquist Priolo Fault Zone. However, the site is located within a state of California Liquefaction Hazard Zone (CGS 1998). SITE N Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 3 ALBUS & ASSOCIATES, INC. Several previous geotechnical reports have been performed for nearby properties. The most comprehensive report we found was for the property located at 225 E. Bay Front (EGA 2017) located about 360 feet north of the subject site. This previous work included one boring extending to a depth of 10 feet and a cone penetration test (CPT) sounding that extended to a depth of 50 feet. The report also provided results of laboratory testing including in-place moistures and densities, maximum density, direct shear, and sulfate content. Copies of the previous exploration and laboratory testing are provided in Appendix A. 2.0 INVESTIGATION 2.1 SUBSURFACE INVESTIGATION Subsurface exploration for this investigation was conducted on August 6, 2021. Our exploration consisted of one (1) boring in a selected area of the site. The boring was hand-augered to a depth of about 10 feet below the existing ground surface. Representatives of Albus & Associates, Inc. logged the exploratory excavation. Visual and tactile identifications were made of the materials encountered, and their descriptions are presented on the Exploration Log in Appendix A. The approximate location of the exploratory boring is shown on the enclosed Geotechnical Map, Plate 1. Bulk and relatively undisturbed samples were obtained at selected depths from the boring for subsequent laboratory testing. Relatively undisturbed samples were obtained using a 3-inch O.D., 2.5- inch I.D., California split-spoon soil sampler lined with brass rings. Bulk samples were placed in plastic bags and transported to our laboratory for analyses and testing. The boring was backfilled with auger cuttings upon completion of sampling. 2.2 LABORATORY TESTING Selected samples obtained from the borings were tested in the soil laboratory. Tests consisted of in- place moisture and density. Results of these tests are included on the boring log presented in Appendix B. 3.0 GEOLOGIC CONDITIONS 3.1 GEOLOGIC SETTING The site is situated in the Peninsular Ranges province, which is one of the largest geomorphic units in western North America. Basically, it extends from the Transverse Ranges geomorphic province and the Los Angeles Basin, approximately 900 miles south to the tip of Baja California. This province varies in width from about 30 to 100 miles. It is bounded on the west by the Pacific Ocean, on the south by the Gulf of California and on the east by the Colorado Desert Province. The Peninsular Ranges are essentially a series of northwest-southeast oriented fault blocks. Three major fault zones are found in this province. The Elsinore Fault zone and the San Jacinto Fault zone trend northwest-southeast and are found near the middle of the province. The San Andreas Fault zone borders the northeasterly margin of the province. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 4 ALBUS & ASSOCIATES, INC. 3.2 GEOLOGIC UNITS Based on our review of the geologic literature, previous geotechnical reports, and site exploration, the site is underlain by artificial fills and estuarine deposits. Artificial fill was encountered to the full depth of our boring (10 feet below ground surface). We estimate the artificial fills extend to a depth of about 12 feet based on data collected at 225 E. Bay Front (EGA 2017). The fill materials are generally comprised of interlayered silty sands and fine to medium, poorly-graded sands with occasional sea shells. These materials are typically medium dense and moist near the surface but become wet near a depth of 4 feet. Estuarine deposits underly the artificial fills and extend to a depth of about 40 feet based on data contained in the report by EGA (2017). These materials generally consist of interlayered silty sands and poorly-graded sands that are medium dense but become dense below a depth of about 20 feet. Below a depth of 40 feet, the underlying materials become a stiff silty clay and clay as suggested by the nearby CPT sounding by EGA. These materials may be an upper weathered section of the Capistrano Formation bedrock that is generally comprised of siltstone or the Monterey Formation bedrock that is interbedded siltstone and claystone. Detailed descriptions of the subsurface conditions encountered within the site and nearby surrounding area are provided the exploration logs and CPT soundings contained in Appendices A and B. 3.3 GROUNDWATER Groundwater was encountered in our boring at a depth of 4 below ground surface. The depth to ground water is significantly influenced by the water levels in the nearby channel. Based on our previous experience in the general area, groundwater is likely to vary by 1 to 2 feet due to tidal fluctuations. Our boring was drilled at about the time of high tide (6.07 ft) and therefore, the depth to groundwater of 4 feet that we encountered is very near the shallowest expected depth. 3.4 FAULTING Based on our review of the referenced publications and seismic data, no faults are known to project through or immediately adjacent the site and the site does not lie within an "Earthquake Fault Zone" as defined by the State of California in the Alquist-Priolo Earthquake Fault Zoning Act. Traces of a buried fault are mapped by Morton and Miller (2006) and Morton (1999) to the northeast approximately 1.84 mile away. This fault is not in the relative vicinity of the site and is not indicated on the State of California maps. We do not consider this fault to be a design consideration of the project. Table 3.1 presents a summary of all the known seismically active faults within 10 miles of the site Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 5 ALBUS & ASSOCIATES, INC. TABLE 3.1 Summary of Faults Name Distance (miles) Slip Rate (mm/yr.) Preferred Dip (degrees) Slip Sense Rupture Top (km) Fault Length (km) Newport Inglewood Connected alt 1 1.84 1.3 89 strike slip 0 208 Newport Inglewood Connected alt 2 1.84 1.3 90 strike slip 0 208 Newport-Inglewood (Offshore) 1.84 1.5 90 strike slip 0 66 Newport-Inglewood, alt 1 2.84 1 88 strike slip 0 65 San Joaquin Hills 5.96 0.5 23 thrust 2 27 4.0 ANALYSES 4.1 SEISMICITY 2019 CBC requires seismic parameters in accordance with ASCE 7-16. Unless noted otherwise, all section numbers cited in the following refer to the sections in ASCE 7-16. Per Section 20.3 the project site was designated as Site Class D. We used the OSHPD seismic hazard tool to obtain the basic mapped acceleration parameters, including short periods (SS) and 1-second period (S1) MCER Spectral Response Accelerations. Section 11.4.8 requires site-specific ground hazard analysis for structures on Site Class E with SS greater than or equal to 1.0 or Site Class D or E with S1 greater than or equal to 0.2. Based on the mapped values of SS and S1 the project site falls within this category, requiring site specific hazard analysis in accordance with Section 21.2. However, “A ground motion hazard analysis is not required for structures where: Structures on Site Class D sites with S1 greater than or equal to 0.2, provided the value of the seismic response coefficient Cs is determined by Eq. (12.8-2) for values of T ≤ 1.5Ts and taken as equal to 1.5 times the value computed in accordance with either Eq. (12.8-3) for TL ≥ T > 1.5Ts or Eq. (12.8-4) for T > TL.” Assuming this exception is met for this project, a ground motion hazard analysis is not required and mapped seismic values can be used. Should this exception not be met, a ground motion hazard analysis is required to determine the Design response spectra for the proposed structures at this site. Both mapped and site-specific seismic design parameters are provided in this report as presented in Section 6.2. Details of a ground motion hazard analysis are explained below. According to Section 21.2.3 (Supplement 1), the site-specific Risk Targeted Maximum Considered Earthquake (MCER) spectral response acceleration at any period is the lesser of the probabilistic and the deterministic response accelerations, subject to the exception specified in the same section. The probabilistic response spectrum was developed using the computer program OpenSHA (Field et al., 2013), which implements Method 1 as described in Section 21.2.1.1. Fault Models 3.1 and 3.2 from Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 6 ALBUS & ASSOCIATES, INC. the Third Uniform California Earthquake Rupture Forecast (UCERF3) were used as the earthquake rupture forecast models for the PSHA. In addition to known fault sources, background seismicity was also included in the PSHA. The ground motion Prediction Equations (GMPEs) selected for use in this analysis are those developed for the Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation (NGA) West 2 project. Four GMPEs - Abrahamson et al. (2014), Boore et al. (2014), Campbell and Bozorgnia (2014), and Chiou and Youngs (2014) were used to perform the analysis. In accordance with Section 21.2.2 (Supplement 1), the deterministic spectral response acceleration at each period was calculated as the 84th percentile, 5% damped response acceleration, using NGA-West2 GMPE Worksheet. For this, the information from at least three causative faults with the greatest contribution per deaggregation analysis were used and the larger acceleration spectrum among these was selected as the deterministic response spectrum. The deterministic spectrum was adjusted per requirements in Section 21.2.2 (Supplement 1) where applicable. Both probabilistic and deterministic spectra were subjected to the maximum direction scale factors specified in Section 21.2 to produce the maximum acceleration spectra. Design response spectrum was developed by subjecting the site-specific MCER response spectrum to the provisions outlined in Section 21.3. This process included comparison with 80% code-based design spectrum determined in accordance with Section 11.4.6. The short period and long period site coefficient (Fa and Fv, respectively) were determined per Section 21.3 in conjunction with Table 11.4- 1. Site-specific design acceleration parameters (SMS, SM1, SDS, and SD1) were calculated according to Section 21.4. Per Section 11.2 (definitions on Page 79 of ASCE7-16) for evaluation of liquefaction, lateral spreading, seismic settlements, and other soil-related issues, Maximum Considered Earthquake Geometric Mean (MCEG) peak ground acceleration PGAM shall be used. The site-specific PGAM is calculated per Section 21.5.3, as the lesser of the probabilistic PGAM (Section 21.5.1) and deterministic PGAM (Section 21.5.2), but no less than 80% site modified peak ground acceleration, PGAM, obtained from OSHPD seismic hazard tool. From our analyses, we obtain a PGAM of 0.709g. 4.2 STATIC SETTLEMENT Analyses were performed to evaluate potential for static settlement of foundations. The underlying soils are primarily granular in nature and so an elastic method was used for evaluation. The elastic modulus of the existing soils was estimated from the CPT data in the report by EGA (2017). The plot indicated a correlated soil elastic modulus of 76 ksf per foot based on a cone penetration resistance of 19 tsf per foot of depth. Two conditions were analyzed. The first was to represent a shallow continuous footing embedded near existing grade and the second was based on a continuous basement footing embedded 10 feet below current grade. For the at-grade footing that carries a wall load of 2 kips/ft, we estimate a total settlement of 0.1 inch assuming the upper 2 feet are removed and recompacted. For the basement footing that carries a wall load of 3 kips/ft., we estimate a total settlement of 0.05 inches. Both analyses assume groundwater at a depth of 4 feet below current grade. We also evaluated the potential ground settlement that may be induced by lowering of the groundwater level due to dewatering. Assuming the groundwater is lowered to 12 feet below adjacent surface grades, we estimate a total induced ground settlement of less than 0.1 inches. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 7 ALBUS & ASSOCIATES, INC. 5.0 CONCLUSIONS 5.1 FEASIBILITY OF PROPOSED DEVELOPMENT From a geotechnical point of view, the proposed site improvements are considered feasible provided the recommendations presented in this report are incorporated into the design and construction of the project. Furthermore, it is also our opinion that the proposed development will not adversely impact the stability of adjoining properties if the recommendations presented in this report are incorporated into site development. Key issues that could have significant fiscal impacts on the geotechnical aspects of the proposed site development are discussed in the following sections of this report. 5.2 GEOLOGIC HAZARDS 5.2.1 Ground Rupture No known active faults are known to project through the site nor does the site lie within the boundaries of an “Earthquake Fault Zone” as defined by the State of California in the Alquist-Priolo Earthquake Fault Zoning Act. The closest known active fault is the offshore portion of the Newport Inglewood Fault located about 1.84 miles from the site to the west. Therefore, the potential for ground rupture due to an earthquake beneath the site is considered very low. 5.2.2 Ground Shaking The site is situated in a seismically active area that has historically been affected by generally moderate to occasionally high levels of ground motion. The site lies in relative close proximity to several active faults; therefore, during the life of the proposed structures, the property will probably experience similar moderate to occasionally high ground shaking from these fault zones, as well as some background shaking from other seismically active areas of the Southern California region. Potential ground accelerations have been estimated for the site and are presented in Section 4.1 of this report. Design and construction in accordance with the current California Building Code (CBC) requirements is anticipated to address the issues related to potential ground shaking. 5.2.3 Liquefaction Engineering research of soil liquefaction potential (Youd, et al., 2001) indicates that generally three basic factors must exist concurrently in order for liquefaction to occur. These factors include: A source of ground shaking, such as an earthquake, capable of generating soil mass distortions. A relatively loose silty and/or sandy soil. A relative shallow groundwater table (within approximately 50 feet below ground surface) or completely saturated soil conditions that will allow positive pore pressure generation. The liquefaction susceptibility of the onsite subsurface soils was evaluated by analyzing the potential concurrent occurrence of the above-mentioned three basic factors. The liquefaction evaluation for this site was completed under the guidance of Special Publication 117A: Guidelines for Evaluating and Mitigating Seismic Hazards in California (CDMG, 2008). Based on the criteria above, the site has a risk of liquefaction. The occurrence of liquefaction can lead to seismic settlement of the ground. Analyses were performed by EGA (2017) to estimate the factor Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 8 ALBUS & ASSOCIATES, INC. of safety against liquefaction and seismic settlement based on the CPT data at the nearby property at 225 E. Bay Front. The analyses were based on a PGAM of 0.72 and the results indicate a total settlement of 2.32 inches. Based on our seismic analyses for the site discussed in Section 4.1, we obtain a PGAM of 0.71 which is slightly lower than the value used by EGA. Upon review of their work, we accept the basis and results of that work as representing conditions at the subject site. A copy of the calculations by EGA are provided in Appendix C. Removing and recompacting the upper 3 feet of soils will reduce the seismic settlement within the upper 10 feet to less than 1 inch. Based on these results, the Shallow Liquefaction Mitigation Methods established by the city of Newport Beach can be implemented for mitigation of liquefaction effects. Specific recommendations are provided in Sections 6.3 and 6.4. 5.3 STATIC SETTLEMENT As summarize in Section 4.2, based on the proposed improvements and provided that a uniform blanket of engineered fill is placed as recommended in this report, total and differential settlement is anticipated to be less than 1 inch and 1/2 inch over 30 feet, respectively. These values are considered within tolerable limits of proposed structures and site improvements. 5.4 EXCAVATION AND MATERIAL CHARACTERISTICS The surficial earth materials are anticipated to be relatively easy to excavate with conventional heavy earthmoving equipment where located above the groundwater depth. Excavations below the ground water depth will be saturated and tend to cave unless supported by shoring. In addition, excavations more than about two feet below ground water will tend to sand boil and become unstable unless the zone of excavation is dewatered. Specific recommendations pertaining to dewatering are provided in Section 6.1.9. Offsite improvements exist near the property lines. The presence of the existing improvements may limit removals of unsuitable materials and deeper excavations adjacent the property lines. Shoring will be required where excavations cut below a plane projected down at 1.5 to 1 (H:V) from adjacent property lines. Specific recommendations for temporary shoring are provided in Section 6.1.8. 5.5 SHRINKAGE AND SUBSIDENCE Volumetric changes in earth quantities will occur when excavated onsite soil materials are replaced as properly compacted fill. We estimate the existing surficial soils may shrink approximately 5% to 15% when removed and replaced as compacted fill. Subsidence due to processing of excavations is anticipated to be about 0.10 feet. The estimates of shrinkage and subsidence are intended as an aid for project engineers in determining earthwork quantities. However, these estimates should be used with some caution since they are not absolute values. Contingencies should be made for balancing earthwork quantities based on actual shrinkage and subsidence that occurs during the grading process. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 9 ALBUS & ASSOCIATES, INC. 6.0 RECOMMENDATIONS 6.1 EARTHWORK 6.1.1 General Earthwork and Grading Specifications Earthwork and grading should be performed in accordance with applicable requirements of the grading codes of the City of Newport Beach, California and CAL/OSHA, in addition to recommendations presented herein. 6.1.2 Pre-Grade Meeting and Geotechnical Observation Prior to commencement of grading, we recommend a meeting be held between the owner/developer, City Inspector, grading contractor, civil engineer, and geotechnical consultant, to discuss proposed grading and construction logistics. We also recommend that a geotechnical consultant be retained to provide soil engineering and engineering geologic services during site grading and foundation construction. This is to observe compliance with the design specifications and recommendations, and to allow design changes in the event that subsurface conditions differ from those anticipated. If conditions are encountered during construction that appears to be different than those indicated in this report, the project geotechnical consultant should be notified immediately. Design and construction revisions may be required. 6.1.3 Site Clearing Vegetation, concrete slabs and foundations, underground improvements to be abandoned and deleterious materials should be removed from the site. Onsite disposal systems consisting of septic tank and seepage pits are not anticipated at the site. If onsite disposal systems are encountered during site development, the septic tank should be completed removed from the site and seepage pits should be properly abandoned in accordance with the requirements established by the government agencies. The project geotechnical consultant should be notified at the appropriate times to provide observation services during clearing operations to verify compliance with the above recommendations. Voids created by clearing and excavation should be left open for observation by the geotechnical consultant. Should any unusual soil conditions or subsurface structures be encountered during site clearing or grading that are not described or anticipated herein, these conditions should be brought to the immediate attention of the project geotechnical consultant for corrective recommendations as needed. Temporary construction equipment (office trailers, power poles, etc.) should be positioned to allow adequate room for clearing and recommended ground preparation to be performed for proposed structures, pavements, and hardscapes. 6.1.4 Ground Preparation Existing soils should be removed to a depth of 2 feet below existing grade below areas to support at- grade footings and slabs on grade. Such removals should extend at least 2 feet beyond the edges of footings. Where footings are supported by soils located below a depth of 8 feet from existing grade (basement condition), no additional removal will be required. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 10 ALBUS & ASSOCIATES, INC. Following removals, the exposed grade should first be scarified to a depth of 6 inches, brought to at least 110 percent of the optimum moisture content, and then compacted to at least 90 percent of the laboratory standard. 6.1.5 Fill Placement In general, materials excavated from the site may be used as fill provided they are free of deleterious materials and particles greater than 4 inches in maximum dimension. Fill materials should be placed in loose lifts no greater than approximately 8 inches in thickness. Each lift should be watered or air- dried as necessary to achieve at least the optimum moisture content, and then compacted in place to at least 90 percent of the laboratory standard. The laboratory standard for maximum dry density and optimum moisture content for each soil type should be determined in accordance with ASTM D 1557. Each lift should be treated in a similar manner. Subsequent lifts should not be placed until the project geotechnical consultant has tested the preceding lift. Lifts should be maintained relatively level and should not exceed a gradient of 20:1 (H:V). 6.1.6 Import Materials If import materials are required to achieve the proposed finish grades, the proposed import soils should have an Expansion Index less than 21 (ASTM D4829). Import sources should be indicated to the geotechnical consultant prior to hauling the materials to the site so that appropriate testing and evaluation of the fill materials can be performed in advance. 6.1.7 Temporary Excavations Due to the sandy nature of the subsurface soils, temporary construction slopes up to 2 feet in depth may be cut vertically provided no surcharge loading is located within a 1:1 plane projected up from the bae of the excavation. Excavations exceeding a depth of 2 feet should be laid back at a minimum gradient of 1.5:1 (H:V) or shored. Recommendations for shoring are provided in Section 6.1.8. Excavations should not be left open for prolonged periods of time. The project geotechnical consultant should observe all temporary cuts to confirm anticipated conditions and to provide alternate recommendations if conditions dictate. All excavations should conform to the requirements of Cal/OSHA. The grading contractor should take appropriate measures when excavating adjacent existing improvements to avoid disturbing or compromising support of existing structures. 6.1.8 Shoring Due to the proximity of the adjacent property lines, shoring should be utilized in the excavation of a basement. In consideration of required cuts and soil conditions, a cantilever system using soldier beams may be used. We assume that site will be dewatered to a depth of at least 2 feet below the cut prior to commencing excavation within the shoring area. If the site is not dewatered to this depth, the following recommendations may require modifications. For a cantilever condition, active pressure should be estimated using the Equivalent Fluid Pressure (EFP) of 37 pounds per cubic foot (pcf) from surface to depth of 3 pile diameters below the cut grade. At greater depths, the active pressure may be disregarded. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 11 ALBUS & ASSOCIATES, INC. The ultimate passive resistance on soldier piles may be taken as an equivalent fluid pressure of 560 pcf. This passive resistance accounts for three-dimensional effects and as such, should only be applied to the actual width of the pile. The allowable passive resistance should be based on applying an appropriate factor of safety to the ultimate value above in consideration of allowable deflections. Generally, a factor of safety of 2.0 is used where no sensitive structures are located within a 1 to 1 projection up from the base of the cut. If shoring will support sensitive features, a greater factor of safety should be applied. Because this is a temporary shoring system, seismic loads are not to be considered. Portions of the shoring may be subjected to additional surcharge loads due to construction equipment. We recommend that such additional loads use the pressure distribution suggested in the NAVFAC manual 7.2. Due to the friable nature of site materials, the excavation should be lagged continuously as the cut progresses. For any additional information or conditions encountered during construction that may vary from those described in this report, this office should be contacted promptly. Shoring plans should be reviewed by this office to verify their compliance with the information and recommendations provided herein. A representative of this office should observe construction of the shoring system. 6.1.9 Dewatering If a basement will be constructed as part of the project, temporary dewatering will be required to allow for shoring and excavation work. Dewatering will generally be required to lower the ground water level to at least 2 feet below the planned excavation depths including footing cuts. Dewatering will generally require the installation of well points around the perimeter of the excavation. Therefore, sufficient room to installation of dewatering wells outside of the shoring should be considered in the site planning. Specific recommendations for dewatering should be prepared by a specialty contactor. The dewatering plans should be reviewed by this office prior to construction. 6.2 SEISMIC DESIGN PARAMETERS 6.2.1 Mapped Seismic Design Parameters For design of the project in accordance with Chapter 16 of the 2019 CBC, the mapped seismic parameters may be taken as presented in the tables below. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 12 ALBUS & ASSOCIATES, INC. TABLE 6.1 2019 CBC Mapped Seismic Design Parameters Parameter Value Site Class D Mapped MCER Spectral Response Acceleration, short periods, SS 1.37 Mapped MCER Spectral Response Acceleration, at 1-sec. period, S1 0.486 Site Coefficient, Fa 1.0 Site Coefficient, Fv 1.8* Adjusted MCER Spectral Response Acceleration, short periods, SMS 1.37 Adjusted MCER Spectral Response Acceleration, at 1-sec. period, SM1 0.875 Design Spectral Response Acceleration, short periods, SDS 0.914 Design Spectral Response Acceleration, at 1-sec. period, SD1 0.583 Long-Period Transition Period, TL (sec.) 8 Seismic Design Category for Risk Categories I-IV II MCER = Risk-Targeted Maximum Considered Earthquake *According to Section 11.4.8 in ASCE 7-16, “a ground motion hazard analysis shall be performed in accordance with Section 21.2 for the following structures on Site Class D and E sites with S1 greater than or equal to 0.2.” However, “A ground motion hazard analysis is not required for structures where: Structures on Site Class D sites with S1 greater than or equal to 0.2, provided the value of the seismic response coefficient Cs is determined by Eq. (12.8-2) for values of T ≤ 1.5Ts and taken as equal to 1.5 times the value computed in accordance with either Eq. (12.8-3) for TL ≥ T > 1.5Ts or Eq. (12.8-4) for T > TL.” The Fv value of 1.8 above from Table 11.4-2 assumes that this exception is met and that a ground motion hazard analysis is not required. Should this exception not be met, the site-specific seismic design parameters provided in the next section should be used. 6.2.2 Site-Specific Seismic Design Parameters In addition to the Code Spectra parameters presented in Table 6.1, we have performed a site-specific ground motion hazard analysis in accordance with Chapter 21 of ASCE 7-16 to obtain site-specific seismic design acceleration parameters, the risk-targeted maximum considered earthquake response spectrum, and the design earthquake response spectrum. The site-specific seismic design parameters are presented below. 6.3 CONVENTIONAL FOUNDATION DESIGN 6.3.1 General The following design parameters are provided to assist the project structural engineer to design the foundations of the proposed residential development at the site assuming the structure will be at grade without a basement. These design parameters are based on typical site materials encountered during subsurface exploration and are provided for preliminary design purposes. Depending on actual materials encountered during site grading and actual foundation loads, the design parameters presented herein may require modification. Where the project will include a basement, the structure should be supported by a mat as discussed in Section 6.4. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 13 ALBUS & ASSOCIATES, INC. TABLE 6.2 2019 CBC Site Specific Seismic Design Parameters Parameter Value Site Class D Site Coefficient, Fa 1.0 Site Coefficient, Fv 2.5 Adjusted MCE Spectral Response Acceleration, short periods, SMS 1.579 Adjusted MCE Spectral Response Acceleration, at 1-sec. period, SM1 1.096 Design Spectral Response Acceleration, short periods, SDS 1.053 Design Spectral Response Acceleration, at 1-sec. period, SD1 0.73 MCE = Maximum Considered Earthquake 6.3.2 Soil Expansion The recommendations presented herein are based on soils with a Very Low expansion potential (EI≤20). Following site grading, additional testing of site soils should be performed by the project geotechnical consultant to confirm the basis of these recommendations. If site soils with higher expansion potentials are encountered or imported to the site, the recommendations contained herein may require modification. 6.3.3 Settlement Considerations As summarized in Section 5.3, based on anticipated foundation loads, and provided that a uniform blanket of engineered compacted fill has been placed, total and differential static settlement under the weight of anticipated residential structures are anticipated to be less than 1 inch and 1/2 inch over 30 feet, respectively. These values are considered within tolerable limits of proposed structures and site improvements. The structure may also be subject to total and differential settlement due to the occurrence of liquefaction as discussed in Section 5.2.3. Recommendations provided herein are intended to mitigate settlement from seismic settlement but may require more restrictive design considerations based on recommendations from the structural engineer. Such recommendations should supersede the recommendations contain herein if more restrictive. 6.3.4 Allowable Bearing Value Provided site grading is performed in accordance with the recommendations presented in this report, a bearing value of 2,000 pounds per square foot (psf) may be used for continuous footings having a minimum width of 12 inches and founded at a minimum depth of 15 inches below the lowest adjacent finished grade. The allowable bearing value presented herein includes both dead and live loads and may be increased by one-third for wind and seismic forces. 6.3.5 Lateral Resistance A passive earth pressure of 200 pounds per square foot per foot of depth up to a maximum value of 1500 pounds per square foot may be used to determine lateral bearing for footings. The passive earth pressure may be increased by one-third for wind and seismic forces. A coefficient of friction of 0.39 times the dead load forces may also be used between concrete and the supporting soils to determine lateral sliding resistance, however, no increase in the coefficient of friction is allowed. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 14 ALBUS & ASSOCIATES, INC. The above values are based on footings placed directly against compacted fill. In the case where footing sides are formed, all backfill against the footings should be compacted to at least 90 percent of the laboratory standard. 6.3.6 Footing and Slab on Grade Exterior and interior building footings should be founded at a minimum depth of 24 inches below the lowest adjacent grade. All continuous footings should be reinforced with a minimum of four No. 5 bars, two top and two bottom. The structural engineer may require different reinforcement and should dictate if greater than the recommendations provided herein. Exterior and interior isolated pad footings should be a minimum of 24 inches square and founded at minimum depths of 24 inches below the lowest adjacent final grade. All pad footings should be tied in both directions to adjacent footings using a grade beams that are at least 12 inches in width and 24 inches in depth. The grade beams should be reinforced with a minimum of four No. 5 bars, two top and two bottom. Interior concrete slabs constructed on grade should be a minimum 5 inches thick and should be reinforced with No. 4 bars spaced 12 inches on center, each way. Care should be taken to ensure the placement of reinforcement at mid-slab height. The slab should be doweled to the footings with No. 4 bars spaced no more than 24 inches on center. The structural engineer may recommend a greater slab thickness and reinforcement based on proposed use and loading conditions and such recommendations should govern if greater than the recommendations presented herein. Concrete floor slabs in areas to receive carpet, tile, or other moisture sensitive coverings should be underlain with a minimum of 10-mil moisture vapor retarder conforming to ASTM E 1745-11, Class A. The membrane should be properly lapped and sealed. The membrane should be underlain by at least 2 inches of sand having an SE of 30 or greater. This vapor retarder system is anticipated to be suitable for most flooring finishes that can accommodate some vapor emissions. However, this system may emit more than 4 pounds of water per 1,000 sq. ft. and therefore, may not be suitable for all flooring finishes. Additional steps should be taken if such vapor emission levels are too high for anticipated flooring finishes. Special consideration should be given to slabs in areas to receive ceramic tile or other rigid, crack- sensitive floor coverings. Design and construction of such areas should mitigate hairline cracking as recommended by the structural engineer. Garage floor slabs should have the minimum thickness and reinforcing as described above. Consideration should be given to providing a vapor retarder below the garage slab to mitigate the potential for effervescence on the slab surface. Block-outs should be provided around interior columns to permit relative movement and mitigate distress to the floor slabs due to differential settlement that will occur between column footings and adjacent floor subgrade soils as loads are applied. Prior to placing concrete, subgrade soils below slab-on-grade areas should be thoroughly moistened to provide a moisture content that is equal to or greater than the optimum moisture content to a depth of 12 inches. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 15 ALBUS & ASSOCIATES, INC. 6.3.7 Footing Observations Footing excavations should be observed by the project geotechnical consultant to verify that they have been excavated into competent bearing soils and to the minimum embedment recommended above. These observations should be performed prior to placement of forms or reinforcement. The excavations should be trimmed neat, level and square. Loose, sloughed or moisture-softened materials and debris should be removed prior to placing concrete. 6.4 MAT SLAB If the home will be underlain by a basement that extends below current ground level, the home should be supported on a concrete mat. The mat should be a minimum of 8 inches in thickness. However, the structural engineer may require a greater thickness and should govern if more. An average net bearing pressure of up to 750 pounds per square foot (psf) under static conditions may be used to design a mat foundation. Local bearing pressures under static and seismic conditions should be limited to 2,000 psf and 2,660 psf, respectively. A passive earth pressure of 190 pounds per square foot per foot of depth may be used to determine lateral bearing for the mat. A coefficient of friction of 0.39 times the effective dead load forces may also be used between concrete and the supporting soils to determine lateral sliding resistance. The passive pressure may be increased by 1/3 for wind and seismic loading. However, no increase should be applied to the friction factor. Design of the mat may be based on a standard modulus of subgrade reaction (Kv1) of 50 pci. The modulus is based on an effective loading area of 1 foot by 1 foot. The modulus may be adjusted for other effective loading areas using the equation provided below. 2 1 2 1)(b bKpcikvb where “b” is the effective width of loading (min. dimension) in ft. The mat should also be designed to tolerate a maximum total and differential seismic settlement of up to 2.5 inches and 1.7 inches over 30 feet, respectively. Based on the State of California Special Publication 117A, hazards from liquefaction should be mitigated to the extent required to reduce seismic risk to “acceptable levels”. The acceptable level of risk means, “that level that provides reasonable protection of the public safety” [California Code of Regulations Title 14, Section 3721 (a)]. As such, the mat need not be designed to prevent cracking of the superstructure as a result of seismic settlement. The mat is anticipated to be permanently located below groundwater. As such, the mat will be subjected to a vertical uplift force (buoyancy). We recommend the mat and structure be designed to accommodate a groundwater elevation that is 3 feet below current ground surface. The sections of the basement located below this elevation should also be designed to be water-tight. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 16 ALBUS & ASSOCIATES, INC. 6.5 RETAINING AND SCREENING WALLS 6.5.1 General The following recommendations are provided for preliminary design purpose. Final retaining wall designs specific to the site development should be provided to us for review once completed. The structural engineer and architect should provide recommendations for sealing at all joints and applying moisture-proofing material on the back of the walls. 6.5.2 Allowable Bearing Value and Lateral Resistance Retaining and free-standing wall footings should be founded in engineered compacted fill. Retaining walls may utilize the bearing capacities and lateral resistance values provided in Sections 6.3.4 and 6.3.5 provide those footings are not located below groundwater. The above values are based on footings placed directly against properly compacted fill or competent native soil. In the case where footing sides are formed, all backfill against the footings should be compacted to at least 90 percent of the laboratory standard. 6.5.3 Active Earth Pressures Static and seismic earth pressures for level backfill conditions are provided in Table 6.2. Seismic earth pressures provided herein are based on the method provided by Seed & Whitman (1970) using a peak ground acceleration (PGA) of 0.47g which represents a 10% chance of exceedance in 50 years. As indicated in Section 1803.5.12 of the 2016 CBC, retaining walls supporting 6 feet of backfill or less are not required to be designed for seismic earth pressures. The values provided in the following table are based on using backfill consisting of select, relatively granular site materials with Very Low expansion potential (0<EI<21). The select material should be placed within a 1:1 plane projected up from the base of the wall stem. In addition, the values are based on drained backfill conditions and do not consider hydrostatic pressure. Furthermore, retaining walls should be designed to support adjacent surcharge loads imposed by other nearby footings or traffic loads in addition to the earth pressure. 6.5.4 Drainage and Moisture-Proofing Portions of retaining walls above groundwater should be constructed with a perforated pipe and gravel subdrain to prevent entrapment of water in the backfill. The perforated pipe should consist of 4-inch- diameter, ABS SDR-35 or PVC Schedule 40 with the perforations laid down. The pipe should be embedded in ¾- to 1½-inch open-graded gravel wrapped in filter fabric. The gravel should be at least one foot wide and extend at least one foot up the wall above the footing and drainage outlet. Drainage gravel and piping should not be placed below outlets and weepholes. Filter fabric should consist of Mirafi 140N, or equal. Outlet pipes should be directed to positive drainage devices. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 17 ALBUS & ASSOCIATES, INC. TABLE 6.2 EARTH PRESSURES Pressure Diagram Static Seismic Total Component Component Force Pressure Values Value Backfill Condition 1. Level above groundwater Level below groundwater2. A 37H 80H. B 14H 14H C 25.5H 47H Note 1.:H is in feet and resulting pressure is in psf. Design may utilize either the sum of the static component and the seismic component force diagrams or the total force diagram above. SEAOSC has suggested using a load factor of 1.7 for the static component and 1.0 for the seismic component. The actual load factors should be determined by the structural engineer. Note 2.: Forces include the hydraulic pressure The use of weepholes may be considered in locations where aesthetic issues from potential nuisance water are not a concern. Weepholes should be 2 inches in diameter and provided at least every 6 feet on center. Where weepholes are used, perforated pipe may be omitted from the gravel subdrain. Retaining walls supporting backfill should also be coated with a moisture-proofing compound or covered with such material to inhibit infiltration of moisture through the walls. Moisture-proofing material should cover any portion of the back of wall that will be in contact with soil and should lap over and onto the top of footing. The top of footing should be finished smooth with a trowel to inhibit the infiltration of water through the wall. The project structural engineer should provide specific recommendations for moisture-proofing, water stops, and joint details. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 18 ALBUS & ASSOCIATES, INC. 6.5.5 Footing Reinforcement All continuous retaining wall footings that are not part of the habitable structure should be reinforced with a minimum of two No. 4 bars, one top and one bottom. For footings that support the habitable structure, refer to Section 6.3. The structural engineer may require different reinforcement and should dictate if greater than the recommendations provided herein. Where recommended removals are limited due to space restrictions, greater reinforcement may be recommended. Specific recommendations should be provided by the geotechnical consultant during grading based on as-built conditions exposed in the field. 6.5.6 Footing Observations Footing excavations should be observed by the project geotechnical consultant to verify that they have been excavated into competent bearing soils and to the minimum embedment recommended herein. These observations should be performed prior to placement of forms or reinforcement. The excavations should be trimmed neat, level and square. Loose, sloughed or moisture-softened materials and debris should be removed prior to placing concrete. 6.5.7 Retaining Wall Backfill Onsite soils may generally be used for backfill of retaining walls provided they are free of deleterious materials and particles greater than 4 inches in maximum dimension. The project geotechnical consultant should approve all backfill used for retaining walls. Wall backfill should be moisture- conditioned to slightly over the optimum moisture content; placed in lifts no greater than 12 inches in thickness, and then mechanically compacted with appropriate equipment to at least 90 percent of the laboratory standard. Hand-operated compaction equipment should be used to compact the backfill placed immediately adjacent the wall to avoid damage to the wall. Flooding or jetting of backfill material is not recommended. 6.5.8 Wall Jointing All site walls above groundwater should be provided with cold joints through the masonry block section at horizontal spacing generally not exceeding 40 feet. If walls will be constructed in locations where removal of unsuitable soils was restricted to less than a 1 to 1 projection down from the foundation (such as property boundaries) the joints should be provided every 20 feet. The joints should not extend through the footing. 6.6 CONCRETE MIX DESIGN Laboratory testing of on-site soils indicates negligible soluble sulfate content. However, the site is in close proximity to salt water. As such, we recommend following the procedures provided in ACI 318, Section 4.3, Table 4.3.1 for C2 exposure for which includes the requirements for a maximum w/c ratio of 0.40 and minimum compressive strength of 5,000 psi.. Upon completion of rough grading, an evaluation of as-graded conditions and further laboratory testing should be completed for the site to confirm or modify the recommendations provided in this section. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 19 ALBUS & ASSOCIATES, INC. 6.7 EXTERIOR FLATWORK Exterior flatwork should be a nominal 4 inches thick. Cold joints or saw cuts should be provided at least every 15 feet in each direction. Special jointing detail should be provided in areas of block-outs, notches, or other irregularities to avoid cracking at points of high stress. Subgrade soils below flatwork should be moistened to achieve a minimum of 110 percent of optimum moisture content to a depth of 12 inches. Moistening should be accomplished by lightly spraying the area over a period of a few days just prior to pouring concrete. The geotechnical consultant should observe and verify the density and moisture content of subgrade soils prior to pouring concrete to ensure that the required compaction and pre-moistening recommendations have been met. Drainage from flatwork areas should be directed to local area drains or other appropriate collection devices designed to carry runoff water to the street or other approved drainage structures. Flatwork adjacent entry points to structures should have a minimum slope of 0.5% away from the structure. 6.8 POST GRADING CONSIDERATIONS 6.8.1 Site Drainage and Irrigation The ground immediately adjacent to foundations should be provided with positive drainage away from the structures in accordance with 2016 CBC, Section 1804.3. However, the ground slope may be limited to 2% for climatic and soils conditions. No rain or excess water should be allowed to pond against structures such as walls, foundations, flatwork, etc. Excessive irrigation water can be detrimental to the performance of the proposed site development. Water applied in excess of the needs of vegetation will tend to percolate into the ground. Such percolation can lead to nuisance seepage and shallow perched groundwater. Seepage can form on slope faces, on the faces of retaining walls, in streets, or other low-lying areas. These conditions could lead to adverse effects such as the formation of stagnant water that breeds insects, distress or damage of trees, surface erosion, slope instability, discoloration and salt buildup on wall faces, and premature failure of pavement. Excessive watering can also lead to elevated vapor emissions within buildings that can damage flooring finishes or lead to mold growth inside the home. Key factors that can help mitigate the potential for adverse effects of overwatering include the judicious use of water for irrigation, use of irrigation systems that are appropriate for the type of vegetation and geometric configuration of the planted area, the use of soil amendments to enhance moisture retention, use of low-water demand vegetation, regular use of appropriate fertilizers, and seasonal adjustments of irrigation systems to match the water requirements of vegetation. Specific recommendations should be provided by a landscape architect or other knowledgeable professional. 6.8.2 Utility Trenches Trench excavations should be constructed in accordance with the recommendations contained in Section 6.1.7 of this report. Trench excavations must also conform to the requirements of Cal/OSHA. Trench backfill materials and compaction criteria should conform to the requirements of the local municipalities. As a minimum, utility trench backfill should be compacted to at least 90 percent of the laboratory standard. Materials placed within the pipe zone (6 inches below and 12 inches above the pipe) should consist of particles no greater than ¾ inches and have a SE of at least 30. The materials Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 20 ALBUS & ASSOCIATES, INC. within the pipe zone should be moisture-conditioned and compacted by hand-operated compaction equipment. Above the pipe zone (>1 foot above pipe), the backfill may consist of general fill materials. Trench backfill should be moisture-conditioned to slightly over the optimum moisture content, placed in lifts no greater than 12 inches in thickness, and then mechanically compacted with appropriate equipment to at least 90 percent of the laboratory standard. For trenches with sloped walls, backfill material should be placed in lifts no greater than 8 inches in loose thickness, and then compacted by rolling with a sheepsfoot roller or similar equipment. The project geotechnical consultant should perform density testing along with probing to verify that adequate compaction has been achieved. Within shallow trenches (less than 18 inches deep) where pipes may be damaged by heavy compaction equipment, imported clean sand having a SE of 30 or greater may be utilized. The sand should be placed in the trench, thoroughly watered, and then compacted with a vibratory compactor. For utility trenches located below a 1:1 (H:V) plane projecting downward from the outside edge of the adjacent footing base or crossing footing trenches, concrete or slurry should be used as trench backfill. 6.9 PLAN REVIEW AND CONSTRUCTION SERVICES We recommend that Albus & Associates, Inc. be retained to review the final grading and foundation plans prior to construction. This is to verify that the recommendations contained in this report have been properly interpreted and are incorporated into the project specifications. If we are not provided the opportunity to review these documents, we take no responsibility for misinterpretation of our recommendations. We recommend that a geotechnical consultant be retained to provide soil engineering services during construction of the project. These services are to observe compliance with the design, specifications and recommendations, and to allow design changes in the event that subsurface conditions differ from those anticipated prior to the start of construction. If the project plans change significantly, the project geotechnical consultant should review our original design recommendations and their applicability to the revised construction. If conditions are encountered during construction that appears to be different than those indicated in this report, the project geotechnical consultant should be notified immediately. Design and construction revisions may be required. 7.0 LIMITATIONS This report is based on the proposed development and geotechnical data as described herein. The materials described herein and in other literature are believed representative of the total project area, and the conclusions contained in this report are presented on that basis. However, soil and bedrock materials can vary in characteristics between points of exploration, both laterally and vertically, and those variations could affect the conclusions and recommendations contained herein. As such, observation and testing by a geotechnical consultant prior to and during the grading and construction phases of the project are essential to confirming the basis of this report. Garrett & Heather Bland October 29, 2021 J.N.: 3010.00 Page 21 ALBUS & ASSOCIATES, INC. This report has been prepared consistent with that level of care being provided by other professionals providing similar services at the same locale and time period. The contents of this report are professional opinions and as such, are not to be considered a guaranty or warranty. This report should be reviewed and updated after a period of one year or if the site ownership or project concept changes from that described herein. This report has been prepared for the exclusive use of Garrett & Heather Bland to assist the project consultants in design of the proposed development. This report has not been prepared for use by parties or projects other than those named or described herein. This report may not contain sufficient information for other parties or other purposes. Respectfully submitted, ALBUS & ASSOCIATES, INC Daniel Albus David E. Albus Staff Engineer Principal Engineer G.E. 2455 From:David E. Albus To:Peter Sehorsch Cc:Michael Aquino; Adam Toal Subject:RE: Bland Residence - 125 E Bay Front, Newport Beach Date:Monday, November 1, 2021 9:25:21 AM Attachments:image001.jpg Peter, We did not evaluate or test for storm water infiltration. That was not part of our scope of work. Given the very shallow groundwater conditions and presence of fill soils down to groundwater, infiltration of storm water is not feasible due to limitations set by the LID manual for the Santa Ana Regional Water Quality Control Board. Infiltration in a basin must be at least 5 feet above seasonally high ground water. We encountered water at 4 feet. The LID does not allow infiltration into manmade fills and the site is underlain by fills to near 12 feet in depth. Both of these conditions preclude infiltration. I can provide a separate letter attesting to this infeasibility at no cost in consideration of the lateness of our report. Just let me know. Dave From: Peter Sehorsch <sehorsch@williamhefner.com> Sent: Monday, November 1, 2021 8:55 AM To: David E. Albus <DAlbus@albus-keefe.net> Cc: Michael Aquino <michael@williamhefner.com>; Adam Toal <AToal@toalengineering.com> Subject: Re: Bland Residence - 125 E Bay Front, Newport Beach Good morning Dave, Please let us know by what date you can send the updated report back to us and our Civil engineering team. Please reach out to them directly if you have any questions regarding the missing information. Regards, Peter Sehorsch On Mon, Nov 1, 2021 at 8:51 AM Alexander Vlosky <AVlosky@toalengineering.com> wrote: Hi Peter, This is good to have, but does not have information regarding infiltration that we need to design for. Once we have the infiltration recommendations, we can determine a design to use with respect to water quality. Thanks,