1007091_StormwaterReport.pdf

EMBARCADERO WEST RAIL

SAFETY AND ACCESS

IMPROVEMENT PROJECT

Stormwater Report

Final Submittal

EMBARCADERO WEST RAIL

SAFETY PROJECT - PHASE 1

(OVR/MARKET AND OAK)

Stormwater Report Sensitive / Proprietary

Table of Contents

INTRODUCTION

Revisions Terms and Definitions Project Location Project Stakeholders Applicable Codes and Standards Flood Hazard Analysis Site Conditions Report

STORMWATER ANALYSIS APPROACH

Hydrology Design Criteria Hydraulic Design Criteria

HYDROLOGIC ANALYSIS

Existing Drainage Condition Proposed Drainage Condition

HYDRAULIC ANALYSIS

Storm Drain Pipe Analysis Inlet Capacity and Gutter Spread Analysis

STORMWATER QUALITY EVALUATION

LIST OF APPENDICES

List of Tables Table 1 – Revision Summary Table Table 2 – Drainage Areas Table 3 – 10-YEAR HGL Summary Table 4 – Pipe Capacity Analysis Summary Table 5 – Inlet Capacity Analysis Summary Table 6 – Bioretention Area Sizing Calculations Summary

List of Figures Figure 1 - Site Location Map

List of Appendices Attachment A: FEMA Maps Attachment B: Geotechnical Memo Attachment C: Landscape and Irrigation Plans Attachment D: Mean Annual Precipitation Attachment E: Rainfall Intensity Attachment F: Existing Hydrology Map Attachment G: Proposed Hydrology Map Attachment H: Storm Drain Pipe Results Attachment I: Inlet Capacity & Gutter Spread Calculations Attachment J: Port Water Quality Worksheets Attachment K: MRP2 Evaluation Worksheet Attachment L: Water Quality Drainage Map Attachment M: Bioretention Calculations Attachment N: O&M Plan

1. Introduction

The City of Oakland’s Embarcadero West Rail Safety and Access Improvements Project (EWRSAI) proposes to enhance the safety of several at-grade crossings with Union Pacific Railroad tracks and provide a new Oversize

Vehicle Route (OVR) for oversize vehicle to access the Port Oakland as an alternative to the Adeline bridge.

The safety improvements will provide physical barriers between trains, vehicles, cyclists and pedestrians to delineate safe movements through the crossings. Additionally, the project proposes to construct a multi-use path. This stormwater report defines the major drainage design elements related to the proposed improvements within the project limits. Area wide drainage evaluation, areas beyond the project limits are outside the scope of this report.

The Project spans locations within the City of Oakland (City) and the Port of Oakland (Port) and must comply with two separate NPDES permits. The City has established standards for stormwater analysis and post construction requirements, but the Port only has standards for post construction requirements. The OVR falls under the Port of Oakland’s jurisdiction and must comply with the Ports Post-Construction Stormwater Design

Manual. The rest of the project complies with MRP2.0 following direction from the City.

A. Revisions

The following is a summary showing the revision tracking for the Drainage Report:

TABLE 1 – REVISION SUMMARY TABLE

Revision A Previous Revisions

Date 2/20/2026 Rev Date

Description Final Submittal

Prepared By Brian Duong, PE

Checked By Allene Rieger, PE

Approved By Mohammed Abushaban, PE

B. Terms and Definitions

AC – Acres

AC-FT – Acre feet

ADA – Americans with Disabilities Act

AFBM – Artificial Fill over Bay Mud

AREMA – American Railway Engineering and Maintenance-of-Way Association

BMP – Best Management Practice(s)

CASQA – California Storm Water Quality Association

CCJPA – Capitol Corridor Joint Powers Authority

City – City of Oakland cfs – Cubic feet per second cf – Cubic Feet

CPUC – California Public Utilities Commission

DA – Drainage Area draining to an inlet

Dia –Diameter

DMA – Drainage Management Area for Stormwater Quality

DTSC – Department of Toxic Substances Control

DWQ – Division of Water Quality

ESL – Environmental Screening Levels

Elev. – Elevation

FHWA – Federal Highway Administration

Ft or ft - Foot

GDR – Geotechnical Data Report

HGL – Hydraulic Grade Line

LID – Low Impact Development

MRP – Municipal Regional Stormwater Permit

NPDES – National Pollutant Discharge Elimination System

O&M – Operations and Maintenance

OVR – Overweight Vehicle Route

Port – Port of Oakland

RCP – Reinforced Concrete Pipe

ROW – Right-of-Way

SDDS – City of Oakland Storm Drainage Design Standards

SSA – Autodesk Storm Sewer Analysis

STA – Station value (of street alignment per drawings)

SWMM – Storm Water Management Model

SWPPP – Stormwater Pollution Prevention Plan

SWRCB – State Water Resources Control Board

UPRR – Union Pacific Railroad

B. Project Location The project is in Oakland along Embarcadero West from Market Street to Oak Street and includes work within the Port of Oakland (Port), See Figure 1.

FIGURE 1 - SITE LOCATION MAP

C. Project Stakeholders Design Team

Owner: City of Oakland Department of Transportation

Prime Consultant / Civil Engineer: Parsons, Chris Segur - Project Manager

Design Engineer: JMA Civil, Inc., Brian Duong, P.E. – Civil Engineer

Geotechnical Engineer: Parikh Consultants

Survey: REY Engineers

Agency Stakeholders

City of Oakland (City)

Union Pacific Railroad (UPRR)

Port of Oakland (Port)

Capitol Corridor Joint Powers Authority (CCJPA)

D. Applicable Codes and Standards This report and the resulting design shall comply with the following standards, including all addenda, specifications, and recommended practices.

• City of Oakland Storm Drainage Design Standards, October 2014.

• City Of Oakland Stormwater Supplemental Form MRP 2.0.

• Port of Oakland 2015 Post-Construction Stormwater Design Manual.

• Alameda County C.3 Stormwater Technical Guidance, February 28, 2024, Version 8.1.

• Alameda County Hydrology & Hydraulics Manual 2018.

• California Regional Water Quality Control Board San Francisco Bay Region Municipal Regional

Stormwater NPDES Permit - Order No. R2-2015-0049, NPDES Permit No. CAS612008, issued

November 19, 2015.

• State Water Resources Control Board Water Quality Order No. 2013-0001-DWQ, As Amended By

Order WQ 2015-0133-Exec, Order WQ 2016-0069-Exec, Order WQ 2017-0031-Dwq, Order WQ 2018-0001-Exec, Order WQ 2018-0007-Exec, Order WQ 2019-0009-Exec.

• National Pollutant Discharge Elimination System (NPDES) General Permit No. CAS000004.

• Waste Discharge Requirements (WDRs) For Storm Water Discharges From Small Municipal

Separate Storm Sewer Systems (MS4s) (General Permit).

• California Department of Transportation (Caltrans): Highway Design Manual, July 1, 2020, Seventh

Edition.

• Federal Highway Administration (FHWA): Hydraulic Design Series No. 2, October 2002, Second

Edition.

E. Flood Hazard Analysis

This project primarily is in FEMA’s unshaded Zone X. A portion of the project falls within FEMA’s orange shaded

Zone X, which represents areas of shallow localized flooding from a 100-year storm with an average depth of less than one foot or areas of less than one square mile. The FEMA Flood Insurance Rate Maps (FIRM) numbers for this project are 06001C0066H and 06001C0067H and are provided in Attachment A.

F. Site Conditions Report This Project is required by the Port of Oakland to provide a Site Conditions Report to summarize relevant findings from the site geotechnical investigations, and is included herein.

Soil Type and Geology

The planned OVR appears to be in the vicinity of the 1860 to 1894 shoreline. Existing geologic literature indicates the OVR alignment is in the geologic unit of “afbm” (Artificial Fill over Bay Mud Deposits). The field exploration encountered fill placed during general development of the area. The fill at the planned pavement subgrade consists primarily of granular material (Silty Sands). On the western part of the container yard, the material may also contain old ballast and recycled Asphalt Concrete mixture.

Topography and Groundwater

The existing grade along the OVR appears to range from Elev. 8 to 11 ft, and the existing Embarcadero West is at about Elev. 10 to 12 ft (per Google Earth). Field drilling for the project encountered groundwater at approx.

14 to 16 ft depth below existing ground surface in November 2024. Groundwater is expected to fluctuate with time and tidal changes as the site is next to the bay. The Historically High Groundwater Depth could be at 5 ft per Geotechnical Memo (Parikh, June 12, 2025), which is included in Attachment B.

Existing Soil and Groundwater Contamination

Phase II soil testing was performed by Baseline Environmental Consulting (December 12, 2024). The Baseline report is attached in Appendix E of the Geotechnical Memo. Refer to the Baseline report for details. Per

Baseline report, the shallow soils in the vicinity of Boring BEMB-2, located on Embarcadero West between

Market Street and container yard, have analytical results exceed the construction workers ESLs, commercial/industrial ESLs, and California and federal hazardous waste criteria due to elevated concentrations of metals. The boring is located adjacent to Radius Recycling (former Schnitzer Steel) near

Adeline Street which has been operated as metal recycling facility since 1961. The Radius Recycling facility is currently under active regulatory oversight from the DTSC and Regional Water Board for soil and groundwater contamination. All bioretention for the Port of Oakland which are OVR1, OVR2, OVR4, & OVR5, will be lined to mitigate effects of high groundwater and soil/groundwater contamination.

Other Geotechnical Issues

The OVR is in granular/sandy fill over Bay Mud. Liquefaction potential exists in the fill material per geological data. We anticipated that some post liquefaction settlement may occur in the general area, but that should be tolerable for the purpose of the OVR. Maintenance may be required if necessary.

Additional Site Information

Per the Port of Oakland’s request, the landscaping and irrigation plans are included in Attachment C.

2. Stormwater Analysis Approach

The Project adopts the City’s Storm Drainage Design Standards (SDDS) for hydrologic and hydraulic analysis for all locations within the project limits, but the Project will utilize the post construction requirements based on the agency that has jurisdiction depending on the location of the proposed work.

The Project uses AutoCAD Civil 3D Storm and Sanitary Analysis (SSA) Software for the hydrologic calculations, including modelling the rainfall-runoff losses based on the City’s Modified Rational method. The Modified

Rational Method generally applies when watersheds are less than 320 acres, which the Project meets the criteria for. The Project also uses SSA to analyze and check capacity of all proposed storm drainage improvements.

The Project uses Bentley’s Flowmaster software to model the hydraulic capacity of proposed inlets and gutters.

The combined tributary areas for the project are less than 50 acres, so the Project is categorized as a

Secondary Facility per the City’s SDDS and is furthermore outside of the FEMA Study Zone. Per the SDDS, the

Project hydrology and hydraulics calculations are based on the 10-year storm design storm frequency, which is applied when Projects are outside of the FEMA Study Zone.

The City supplied an HGL map that provides 10-year design storm HGL values for stormwater structures within the Project vicinity. These HGL values are used for downstream tie-in points to reflect. A copy of the map is not included in this report because it is a draft and not yet been adopted by the City Council. This map is a draft document that is not published. Pipes were assumed to be at 80% capacity in areas where no HGL values were provided, per direction from the City.

A. Hydrology Design Criteria The City’s SDDS defines the modified rational by the following formula:

Q = I (C’A)

Where:

Q = Design runoff flow rate (cfs)

I = Rainfall Intensity (in/hr)

C’ = Runoff coefficient modified by slope and rainfall intensity

A = Drainage area (acres)

The following sections summarize the hydrologic analysis performed to quantify the peak flows for each of the drainage areas.

Intensity

The rainfall intensity, I, is computed from the following equation:

I = (0.33 + 0.91144 x MAP) x (0.249 + 0.1006 x K) x T-0.56253

Where:

T = Time of Concentration was assumed to be the minimum value of 5 minutes for drainage areas that do not include buildings due to their small size and to ensure results are conservative. For drainage areas with buildings, time of concentration was calculated assuming 5 minutes for roof to gutter flow plus flow time along the gutter to terminal drainage.

MAP = Mean Annual Precipitation (inches) which is assumed as 20 inches based on Attachment 8 of the SDDS and a copy is included in Attachment D.

K = Frequency factor which is 1.339 for the 10-year design storm applicable to this project.

The SDDS has performed the intensity calculations for various combinations of this factor and presented the results in Attachment 10 which was referenced for this project to establish rainfall intensity for the drainage areas. A copy of the rainfall intensity table is included in Attachment E.

Runoff Coefficient

The SDDS outlines two methods for determining the runoff coefficient for the drainage areas:

1. Compute the formulas stipulated in Section 6.1.3 of the SDDS, or

2. Use the runoff coefficient adjustment table included in Attachment 9 of the SDDS. The weighted average runoff coefficient was calculated for all drainage areas. If the result was 0.8 or greater, then no adjustment to the runoff coefficient was made because the adjustment methodology does not result in runoff coefficients greater than 0.8.

Area

Drainage areas were established based on available topographic data and the proposed grading model using

AutoCAD Civil 3D. Where topographic data did not capture the full footprint of a drainage shed, the design assumed crowned roadways and areas bound by blocks or half-blocks as appropriate based on locations of nearby drainage inlets that were identified in the field.

B. Hydraulic Design Criteria The Project implements the following criteria from the SDDS:

• The freeboard for closed conduits shall not exceed 1.25 feet from design HGL to the top of curb.

• City of Oakland requested the minimum pipe slopes to be 2% or to flow at a minimum of 3 ft/s for a 2-year storm event.

• Minimum pipe size diameter shall be 12” and pipe materials for buried pipe installation shall be

RCP class III or HDPE SDR 11 minimum unless otherwise noted on the plans.

• Access manholes and structures for underground storm drainage conduit shall not exceed 400 feet spacing on center.

• On streets where there is no parking lane, the width of spread shall not exceed the lip of the gutter.

• Where parking lanes and turn lanes begin or where bike lanes are designed, an adequate number of inlets and structures shall be designed to prevent the storm water from reaching the travel lanes.

• Stormwater shall be collected upstream of all intersections, pedestrian walkways, wheelchair ramps, and other public access features. Gutter flow is prohibited across all public access features along the roadway.

3. Hydrologic Analysis

This section describes the drainage areas including their drainage patterns and associated peak flows for the existing and proposed conditions.

A. Existing Drainage Condition

The Project improvements include improvements on the OVR, Market Street, Oak Street and Embarcadero

West. Below is a description of these locations and their existing drainage condition.

OVR

The OVR limits start west of the Market Street at-grade crossing along Embarcadero West that transitions to private road and crosses several UPRR industry track and terminates at the intersection of Adeline Street and

Middle Harbor Road. There are limited existing drainage structures and they are located along Adeline Street, near the Radius Recycling building, and at the Market Street intersection. Existing drainage flows south to north across the road and into the unpaved area. The Port of Oakland noted there is historic ponding near the at-grade crossing.

Market Street

The project limits along Market Street start at the north from 3rd Street and end at the south at the at-grade crossing. Market Street is crowned about its centerline and runoff is collected at the gutter which carries the runoff from north to south and into a pair of existing curb inlets adjacent to the at-grade crossing. An 18” to

24” storm drain pipe runs along the center of Market Street which drains the stormwater runoff into the

Oakland Estuary. The City-provided HGL map shows the existing Market Street storm drain pipes at overcapacity and 10-year HGLs above the rim elevations.

Oak Street

The project limits along Oak Street start at the north from 3rd Street and end approximately 200’ south of the at-grade crossing. Oak Street is crowned about its centerline and runoff is collected at the gutter and drains into existing curb inlets located along Oak Street. The curb inlets drain into laterals that tie into a 4’x6’ box culvert which flows south along Oak Street. The City provided HGL map shows the Fallon Street pipes at overcapacity. This portion of Oak Street was divided into 6 drainage areas that are fully paved and impervious.

Embarcadero West

The project limits along Embarcadero West start from the west at the intersection with Webster and end at the east with the intersection with Oak Street. Embarcadero West is crowned about its centerline and runoff is collected at the gutters and drain into existing curb inlets located along Embarcadero West. The curb inlets drain into laterals that tie into a 12” storm drain line running the south side of Embarcadero West. The existing and proposed drainage areas are set the same because the hydraulic design required along Embarcadero is to calculate the spread width along the proposed median to determine gap spacing in the median to allow runoff to flow to the roadway gutter.

Below is a table which shows the existing tie-in structures and their corresponding HGLs. The sizes and drainage patterns of these drainage areas for the existing condition are illustrated graphically in the drainage maps included in Attachment F.

B. Proposed Drainage Condition The Project improvements include improvements on the OVR, Market Street, Oak Street and Embarcadero

West. Below is a description of these locations and their proposed drainage conditions.

OVR

The OVR is characterized by a new road in the Port that runs parallel to and south of Adeline Street. The roadway grading introduces a grade break in between the two roads that separates runoff from the existing

Adeline Street and OVR surface drainage. The OVR is cross sloped to drain to the south edge of the road, where runoff is conveyed by a concrete curb. Along the length of curb are series of high and low points that subdivide the OVR drainage and discharge into curb cuts and into a concrete ditch behind the curb. Generally, the concrete ditch conveys runoff to proposed drainage inlets that connect to existing storm drain structures and bioretention basins.

OVR has implemented three bioretention basins that are sized per the Port’s Post-Construction Stormwater

Design Manual, and during heavier storms runoff flows into the overflow drainage inlets. Two of these overflows are upstream of an existing curb inlet at Adeline Street, and the third overflow is upstream of an existing curb inlet at the northwest curb return of the Market Street intersection.

Market Street

The Market Street improvements include raising the grade near the UPRR at-grade crossing to comply with FRA grade crossing guidelines. This creates a new low point that is approximately 50’ north of the existing inlet location. In effect, the existing storm drain curb inlets are removed and replaced at the new low point. These structures include a new curb inlet. New 18” pipes downstream of these new structures will replace the existing 12” and 18” storm drain crossings with an increase in storage capacity.

At the 3rd and Market intersection, the project proposes curbed bulb-outs at pedestrian crosswalks. These bulb-outs will maintain the existing flow around the curb returns and drain to the existing inlets.

Market Street is crowned with a median and drains to both edges of the road where runoff is conveyed by new concrete curb and 6’ gutter. This gutter replaces the existing 2’ gutter to increase the hydraulic capacity and comply with the City’s spread width requirement. Runoff is collected by the new curb inlets which drains into the existing 21” storm drain line running south.

Bioretention basins or green infrastructure are not required, but the City requested that bioretention be added where possible. Due to the existing utilities, the depth of the existing storm drain, and the City’s requested minimum pipe velocity, bioretention was not implemented north of the grade crossing. A bioretention basin was placed at the southeast quadrant of Market Street and Embarcadero West which is for the Port of Oakland and collects runoff via curb cuts and overflow riser from the realigned east leg of Embarcadero West.

Oak Street

The Oak Street improvements introduces a new crowned median, which drains runoff to opposite sides of the median. Oak Street also introduce a new multi-use pathway (MUP) along the westside of the street between the Embarcadero West intersection and 3rd Street intersection. Existing storm drain curb inlets are removed and replaced at with new curb inlets or bioretention overflow inlets.

At the 2rd and Oak intersection, the project proposes curbed bulb-outs at pedestrian crosswalks. Two curb inlets are proposed west of the bulb-outs to intercept and capture runoff from 2nd Street, which prevent water from flowing across the crosswalk. The curb inlets drain into a new manhole on 2nd Street and then into an existing manhole at the intersection to avoid utility conflicts.

Oak Street’s crowned median drains to both edges of the road where runoff is conveyed by new concrete curb and 4’ gutter. This gutter replaces the existing 2’ gutter to increase the hydraulic capacity and comply with the

City’s spread width requirement. The gutter runoff on the west side of the median drains to the new curb inlet and into the existing 18” storm drain line running south. The runoff on the both sides of the median drains to new curb cuts that discharge into the bioretention basins, or into new curb inlets that connect to the existing storm drain through Oak Street.

Bioretention basins or green infrastructure are not required, but the City requested that bioretention be added wherever possible. Oak Street has implemented four bioretention basins that are sized using the 4% impervious area rule per the Alameda County’s C.3 Stormwater Technical Guidance. The bioretention basin sizes meet the 4% rule based on their respective drainage sheds, except for the basin at the northeastern return at the UPRR crossing because of limited space.

Embarcadero West

The project will introduce a new MUP along Embarcadero West starting at the intersection with Alice Street and ending at the Oak Street intersection. Proposed curb medians that separate vehicles from the MUP will have curb openings to allow for runoff to flow towards the existing gutter. There are no proposed drainage inlets nor bioretention facilities along Embarcadero West since the improvements are limited to the construction of the new curb median.

The sizes and drainage patterns of the OVR, Market Street, and Oak Street drainage areas for the proposed condition are illustrated graphically in the drainage maps included in Attachment G and summarized in Table 2 below.

TABLE 2 – DRAINAGE AREAS

Drainage Area Area (AC) Drainage Area Area (AC)

OVR-1 0.79 OAK-1 0.18

OVR-2 4.43 OAK-2 0.06

OVR-3 1.04 OAK-3 0.28

OVR-4 0.59 OAK-4 0.21

OVR-5 1.21 OAK-5 0.11

OVR-6 0.87 OAK-6 0.28

MKT-1 1.04 OAK-7 0.25

MKT-2 0.76 OAK-8 0.25

OAK-9 0.25

4. Hydraulic Analysis The project uses hydraulic analysis to size the storm drain pipes, size the drainage inlets, and verify gutter spread width for the proposed improvements. All storm drain improvements tie into the existing storm drainage network. The existing 10-year HGLs as supplied by the City are used at the starting water surface elevations at each of the tie-ins where provided and are summarized in Table 3 below.

TABLE 3 – 10-YEAR HGL SUMMARY

Location Structure Name 10-year HGL Surface

Elevation

OVR EXSDMH001 3.30 9.14

OVR EXDI001 7.15 10.09

OVR EXSDMH002 6.49 10.34

OVR EXDI002 7.19 10.11

MKT SDMH101 10.65 9.69

MKT EXDI101 8.85 10.35

OAK SDMH201 4.74 11.66

OAK SDMH202 5.73 10.50

OAK EX4X6 5.47 10.30

A. Storm Drain Pipe Analysis Storm drain pipe capacity has been calculated using the SSA software modelling the 2-year and 10-year storm events. The City of Oakland requested the 2-year storm event be analyzed if pipe slopes were to be less than

2% because there was concern that the pipes would not flow at 3ft/s if pipe slopes were less than 2%. The pipes within Market Street and Oak Street, which are within the City of Oakland jurisdiction, meet this requirement. The pipes within the OVR are under the Port of Oakland’s jurisdiction and meet their criteria.

The storm drain capacity is a function of longitudinal slope, pipe material and pipe cross section. All proposed storm drain pipes will be RCP and a Manning’s n of 0.014 was used. The kinematic wave routing analysis was use and the calculations are included in Attachment H. The results of the analysis confirm the size of the proposed storm drain pipes meet freeboard criteria and have hydraulic capacity in areas that do not experience historic inundation. Table 4 below summarizes the results for each of the proposed pipes as identified in Attachment H.

TABLE 4 – PIPE CAPACITY ANALYSIS SUMMARY

Location From Node To Node Slope

Diameter (in)

Calculated 10-year

Runoff (cfs)

Pipe Capacity

(cfs)

10-year Pipe Velocity

(ft/s)

Calculated 2-year

Runoff (cfs)

2-year Pipe Velocity

(ft/s)

MKT DI101 SDMH101 0.51 18 0.76 6.94 3.87 0.48 3.50

MKT EXSDMH101 SDMH101 0.72 21 3.42 12.46 4.45 2.16 3.92

MKT SDMH102 EXSDMH101 0.51 21 3.44 10.48 3.90 2.18 3.45

MKT DI102 SDMH102 2.00 18 1.46 13.81 5.08 0.92 4.42

MKT SDMH103 SDMH102 0.50 21 2.11 10.37 3.39 1.34 2.98

MKT DI103 SDMH103 2.00 18 2.12 13.74 5.64 1.34 4.95

MKT DI104 EXDI101 2.00 12 0.06 2.48 2.38 0.04 1.78

OAK DI201 SDMH201 2.00 12 0.51 4.39 4.68 0.32 4.22

OAK DI202 EX12SD 2.00 12 0.17 4.07 3.51 0.11 3.18

OAK DI203 SDMH202 2.00 12 0.90 14.71 10.34 0.57 9.02

OAK SDMH203 DI203 2.00 12 0.31 3.31 2.65 0.20 2.32

OAK DI204 SDMH203 2.00 12 0.31 3.57 3.11 0.20 2.82

OAK NODE201 EX4X6 0.00 48 2.50 120.07 1.67 1.56 1.39

OAK EXDI201 NODE201 4.44 12 0.66 6.97 5.60 0.41 4.89

OAK DI206 EXDI201 4.50 12 0.66 7.02 5.62 0.42 4.90

OAK SDMH204 NODE201 0.20 48 1.86 120.07 1.50 1.16 1.25

OAK DI205 SDMH204 2.00 12 0.66 9.01 6.71 0.42 5.87

OAK DI209 SDMH204 2.00 12 0.58 4.67 4.85 0.37 4.37

OAK SDMH205 SDMH204 0.25 36 0.95 66.79 1.43 0.60 1.20

OAK DI207 SDMH205 2.00 18 0.48 13.77 3.66 0.30 3.11

OAK DI208 SDMH205 2.00 18 0.48 13.78 3.67 0.30 3.19

OVR SDMH001 EXSDMH001-O 0.31 18 5.87 5.43 3.64 4.77 3.47

OVR DI001 SDMH001 0.30 18 6.72 11.54 6.78 4.25 6.03

OVR SDMH002 SDMH001 0.30 18 1.44 5.34 2.76 0.83 2.40

OVR SDMH003 SDMH002 0.30 18 1.58 5.34 2.91 0.95 2.54

OVR SDMH004 SDMH003 0.30 18 1.73 5.36 3.01 1.06 2.69

OVR SDMH005 SDMH004 0.30 18 1.90 5.31 2.96 1.20 2.72

OVR DI009 SDMH005 0.30 18 2.01 5.35 4.66 1.28 4.24

OVR EXDI003 EXDI001 0.00 18 3.75 4.36 2.77 2.37 2.52

OVR DI012 EXDI003 0.30 18 2.29 5.35 5.08 1.45 4.65

OVR DI013 EXSDMH002 2.00 18 1.25 13.80 5.79 0.79 5.25

OVR DI014 EXDI002 2.01 12 2.47 4.69 6.05 1.57 5.38

1 Per the City of Oakland’s draft HGL maps, the HGLs for these pipes exceed the rim elevations of structures during the 10-year storm event. To resolve flooding of Market Street would require extensive storm drain infrastructure upgrades beyond the limits of the project.

2 Greyed out pipes represent existing pipes.

B. Inlet Capacity and Gutter Spread Analysis The inlet and gutter capacity is a function of longitudinal and transverse slope, gutter material, and the inlet opening provided. The results of the analysis confirm the drainage inlets and curb cuts can accommodate the hydraulic demands of the 10-year design storm event for the Projects proposed conditions. Each subsequent curb cut has a bypass flow going into it.

Spread width is a measure of hydraulic capacity of a curb and gutter system, and refers to the width of water flowing in the gutter at a given point. In discussions with the City, the spread width cannot exceed the width of the gutter. The City allows the gutter to extend into the travel lane in order to contain runoff. Gutters are sized to meet the calculated spread widths.

Curb cuts are sized and spaced to accommodate a 125 square foot maximum area of roadway from which runoff drains from, This corresponds to 0.02 cfs, which is the hydraulic capacity of a standard curb cut.

The results of the analysis confirm the gutter capture capacity maintains spread width below the City requirements and also can accommodate the hydraulic demands of the 10-year storm event. The drainage shed map and gutter capacity analysis is included in Attachment I.

Table 5 below summarizes the capacity analysis for each of the proposed gutters as identified in Attachment I.

TABLE 5 – INLET CAPACITY ANALYSIS SUMMARY

DA Q (cfs) Spread Width (ft)

Proposed Gutter Width (ft)

MKT1 2.12 4.1 6.0

MKT2A 1.25 4.9 6.0

MKT2B 0.33 3.0 6.0

OAK1 0.51 1.8 2.0

OAK2 0.18 2.0 2.0

OAK3A 0.66 3.9 4.0

OAK3B 0.15 3.1 4.0

OAK4 0.60 2.1 4.0

OAK5 0.32 3.9 4.0

OAK6 0.81 3.9 4.0

OAK7 0.64 3.8 4.0

OAK8 0.48 3.4 4.0

OAK9 0.48 3.4 4.0

5. Water Quality Requirements

The OVR falls under the Port of Oakland’s jurisdiction and must comply with the Ports Post-Construction

Stormwater Design Manual. The Port has established a worksheet to perform the bioretention volume sizing calculations method and are included in Attachment J. The Port of Oakland was specific in the locations of the bioretention because they did not want to impact the existing Port’s ongoing operations, the existing track, the existing utilities, and future land uses.

Post construction stormwater quality measures were implemented to the maximum extent possible within the limited available space. Bioretention basins were selected as the preferred facility for treating stormwater on the project. Site design measures were not implemented due to site constraints. Vegetated swales were not used due to the minimal grade differential across the site and the contaminated soils. The OVR will need to accommodate heavy loads that porous pavement will not be able to support. Additionally, the OVR is within an industrial area so the pollutants and existing contaminated soils does not justify the use of porous pavement.

Bioretention was provided where feasible for all DMA’s where new impervious surface is proposed. No bioretention was provided for the OVR-3 DMA because the pavement will be resurfaced and is therefore exempt from water quality requirements. Although not all the drainage within the Market Street intersection will flow into a bioretention, an equivalent area of resurfaced pavement will drain to bioretention.

Per the City of Oakland requirements for stormwater include completing the MRP2 and Green Infrastructure

Potential worksheet to determine if the project is a C3-regulated project. JMA completed the form and determined that this project does not fall into this category. The City of Oakland reviewed the form and confirmed that the project is not a C3-regulated project, but requested that green stormwater infrastructure be implemented where feasible. The primary green stormwater infrastructure applied for the project are bioretention basins: shallow landscaped basins that utilize the natural physical, biological, and chemical processes of vegetation growth in soils to collect, detain, filter, and absorb stormwater runoff. A copy of the

MRP2 and Green Infrastructure Potential worksheet is included in Attachment K.

Bioretention basins are proposed along Oak St. The Water Quality Drainage map is included in Attachment L.

These GSI features were sized based on the Alameda County’s C.3 Stormwater Technical Guidance, which requires that bioretention basins are sized based on a 4% surface area of each drainage area. While this is the standard criteria for sizing green infrastructure, the 4% rule served as a minimum. Where more space was available, bioretention area was provided when feasible to potentially account for greater detention capacity.

The sizing calculations are included in Attachment M and summarized in Table 6 below.

Some areas were determined to be infeasible due to extensive existing utility relocation, space constraints, and lack of existing storm drain infrastructure to connect to.

TABLE 6 – BIORETENTION AREA SIZING CALCULATIONS SUMMARY

STREET

NAME DMA

Impervious Area Proposed

(SF)

Bioretention Area Proposed

(SF)

Bioretention Area Required

(SF)

Stormwater Jurisdiction

OVR OVR-1 41,980 4,369 1,814 Port OVR OVR-2 10,990 1,800 490 Port OVR OVR-4 9,120 785 428 Port OVR OVR-5 5,860 281 201 Port

OAK OAK-1 12,159 261 4871,2 City

OAK OAK-2 1,222 227 491 City OAK OAK-3 652 62 261 City OAK OAK-4 3,585 160 1431 City

1 Bioretention area required is obtained using 4% of impervious area rule, but meeting C3 is not required by MRP2.

2 Bioretention area provided is less than the C3 requirement due to site constraints and design conflicts.

The Operations and Maintenance Plan for the bioretention is included in Attachment N.

Stormwater Report Sensitive / Proprietary 17

List of Appendices

Attachment B: Geotechnical Memo

Attachment C: Existing HGL Information

Attachment D: Mean Annual Precipitation Map

Attachment E: Rainfall Intensity Table

Attachment F: Existing Hydrology Maps

Attachment G: Proposed Hydrology Map

Attachment H: Storm Drain Pipe Results

Attachment I: Inlet Capacity Calculations

Attachment J: Port Water Quality Worksheets

Attachment K: MRP2 Evaluation Worksheet

Attachment L: Water Quality Drainage Map

Attachment M: Bioretention Calculations

Attachment N: O&M Plan

A tta c h m e n t A

: F E

M A

M a p s

A tta c h m e n t B

: G e o te c h n ic a l M e m o

Attachment B: Geotechnical Memo

1497 N, Milpitas Blvd, Milpitas, CA 95035 l P (408) 452-9000 l www.PARIKHnet.com l SF Bay Area l Sacramento l SoCal

MEMORANDUM

To: Parsons June 12, 2025 555 12th Street, Suite 2130 Job No.: 2024-116-GEO Oakland, CA 94607

Attn: Mr. Jeff Sparks, P.E.

From: David Wang, PhD, PE 52911

Subject: Pavement Design Memo Embarcadero West Rail Safety and Access Improvements

City of Oakland, CA

Introduction

This memo presents the geotechnical recommendations for the proposed Embarcadero West

Rail Safety and Access Improvements Project. The proposed base improvements being considered are at eight (8) at-grade intersections (Market Street, Martin Luther King Jr. Way, Clay

Street, Broadway, Washington Street, Franklin Street, Webster Street, and Oak Street), which include new railroad and pedestrian crossing-related facilities and improvements. In addition, a multi-use trail (Class I path) on Embarcadero West between Martin Luther King Jr. Way and

Webster Street is planned.

The project also includes an Overweight Vehicle Route and Emergency Vehicle Access roadway.

The new roadway connects Adeline Street to Market Street via Embarcadero West that will accommodate overweight vehicles and emergency vehicles. The general location of

Embarcadero West is shown on Plate No. 1, Project Location Map.

Scope of Work

The scope of work includes coring the existing pavement to determine the thicknesses of the existing asphalt and concrete pavement, collecting representative subgrade soil samples for R-

Value testing, verifying groundwater level, laboratory testing, engineering analysis of the data and interaction with the designer, and preparation of this report. The scope also includes limited environmental testing work performed by Baseline Environmental consultants. The report prepared by Baseline Environmental is attached in Appendix E.

http://www.parikhnet.com/

Parsons Job No: 2024-116-GEO (Embarcadero West Rail Safety) June 12, 2025

Field Exploration

The scope of work includes coring the existing pavement to determine the thicknesses of the existing asphalt and concrete pavement, collecting representative subgrade soil samples for R-

Value testing, The field exploration program consisted of a total of 15 exploration locations for pavement coring. Eleven locations were also drilled with auger to obtain subgrade soil samples for R-values to about 5 feet depth, except that three of them were drilled to 16.5 feet to verify groundwater levels. The R-value samples and pavement coring data provide information for the roadway rehabilitation / improvement design. The exploration locations are shown on Plate Nos. 2-1 through 2-4, Boring Location Plan.

All boreholes were advanced with hollow stem augers. Existing HMA and Portland Cement

Concrete (PCC) core samples were retrieved, and representative bulk samples were obtained from drill cuttings. Photographs of the HMA and PCC cores are attached in Appendix C.

Site Geology and Subsoil Conditions

The site geology is referred to Seismic Hazard Zone Report (SHZR 081) for the Oakland West 7.5-minute Quadrangle (California Geological Survey, 2003), top portion of Plate No. 3. The map indicated that majority of Embarcadero West is located in the geologic unit of “afbm” (Artificial fill over Bay Mud deposits). In our experience, the pavement subgrade soils tend to consist of man-made fill that usually could be sandy but may be mixed with soft fine-grained silts and clay along shoreline.

According to the Historical Shoreline Map presented on Plate No. 4, Embarcadero West is along the 1860 shoreline. It is anticipated that the Embarcadero West was developed through land reclamation during development of the area. The exploration data indicated that the pavement subgrade soils consist primarily of silty sand and clayey sand mixed with some gravel and trace clays at some locations.

The planned Overweight Vehicle Route (OVR) appears to be in the vicinity of the 1860 to 1894 shoreline. Existing geologic literature indicates the OVR alignment is in the geologic unit of

“afbm” (Artificial Fill over Bay Mud Deposits). The field exploration encountered fill placed during general development of the area. The fill at the planned pavement subgrade consists primarily of granular material (Silty Sands). On the western part of the container yard, the material may also contain old ballast and recycled Asphalt Concrete mixture.

Groundwater

Three (3) borings were drilled to 16.5 feet below grade to verify groundwater level. Two borings

(near junctions of Embarcadero West and Market Street and Clay Street) did not encounter groundwater during drilling in November 2024. The boring located at the junction of

Embarcadero West and Webster Street encountered groundwater at 14 feet below grade. The existing grade along the OVR appears to range from Elev. 8 to 11 feet, and the existing

Embarcadero West is at about Elev. 10 to 12 feet (per Google Earth). Field drilling for the project encountered groundwater at approx. 14 to 16 ft depth below existing ground surface in

November 2024.

The depth contours of the Historically High Groundwater Level are also summarized in the SHZR

081 report for Oakland west, as shown at the bottom portion of Plate No. 3. Based on the data, the Historically High Groundwater Level could be as high as 5 feet depth. The groundwater data from the referenced report were interpreted from borehole logs from investigations conducted between the 1950’s and 1999.

Please note that groundwater levels are anticipated to vary with the passage of time due to seasonal fluctuations, surface and subsurface flow, surface run-off and other factors that were not present at the time of investigation.

Other Geotechnical Issues

The general OVR and Embarcadero West are in granular/sandy fill over Bay Mud. Liquefaction potential exists in the fill material per geological data. We anticipated that some post liquefaction settlement may occur in the general area, but that should be tolerable for the purpose of the OVR and roadway improvements. Maintenance may be required if necessary.

Exploration Data

The existing pavement thickness, subgrade soils encountered, and lab data are summarized in the following table.

Table 1 -Summary of Existing Pavement Sections, Subgrade Soil & Laboratory Test Results

Boring No.

Existing Pavement Sections

Subgrade Material Description Lab Test Results

HMA

Thickness (Inches)

Concrete Thickness

PCC (Inches)

Aggregate Base

(Inches)

BEMB-1

(Embarcadero West)

15± -- -- Silty sand (SM), dark brown, moist, some subrounded gravel

R = 75

BEMB-2

(Embarcadero West)

(Boring is away from travel lane)

9” of angular gravel (up to 1.5” size) over silty sand with clay, dark brown

R = 73

LL = 34%

PI = 16%

YD-1

(Container Yard)

9-1/2± -- -- Silty sand, brown --

YD-2

(Container Yard)

14-1/2± -- -- Silty sand, brown --

BEMB-3

(Embarcadero West)

(No existing pavement in the area)

9” of silty sand with angular gravel (up to 1.5” size) over silty sand, brown, moist

R = 80 +#4 = 24.6%

-#200 = 15.1%

YD-3

(Container Yard)

(No existing pavement in the area) -- -- Ballast and recycled AC mixture --

YD-4

(Container Yard)

(No existing pavement in the area) -- -- Ballast and recycled AC mixture --

BMKT-1

(Market St)

4-1/4± 5-3/4± --

Clayey sand (SC), gray-brown, moist, medium plasticity. Groundwater was not encountered thru 16.5’ during drilling.

R = 75 +#4 = 0.0%

-#200 = 30.8%

BMLK-1

(MLK Jr. Way)

9± 6± -- Clayey sand (SC), brown, moist R = 76

BC-1

(Clay St)

4± 5± -- Silty sand (SM), brown, fine sand.

Groundwater was not encountered thru 16.5’ during drilling.

+#4 = 3.1% -#200 = 19.6%

BWash-1 (Wahington St)

5± 5± -- Silty sand (SM), brown, fine sand +#4 = 6.7%

-#200 = 20.7%

BB-1

(Broadway)

4-3/4± 9± -- Sandy silt to Silty sand (ML/SM), brown, moist, find sand, low plasticity

R = 68

BF-1

(Franklin St)

5-3/4± 6± Silty sand (SM), brown, fine sand R = 73

BWeb-1 (Webester St)

4± 7± --

Sandy silt to Silty sand (ML/SM), brown, moist, find sand, low plasticity.

Groundwater was encountered at 14’ during drilling.

+#4 = 0.5% -#200 = 20.8%

BO-1

(Oak St)

16-1/2± -- Sandy silt to Silty sand (ML/SM), brown, moist, find sand, non-plastic

R = 73

Note: HMA- Hot Mix Asphalt/Asphaltic Concrete PCC- Portland Cement Concrete

Structural Pavement Design Sections

Based on the exploration and lab test data, an R-value of 40 is recommended for pavement design in native sandy subgrade. The Design Traffic Indices (TI) at various junctions were provided by the designer.

Flexible Pavement Sections. TI values of 7.0 to 13.0 were provided. The pavement section designs were prepared in accordance with the State of California Department of Transportation

(Caltrans) conventional empirical design procedures. For the proposed Overweight Vehicle

Access Route connecting Adeline Street to Market Street, we understand that the overweight vehicle has been factored in determining the design TI (11.5).

Based on discussion with the designer, two design options were considered:

• Total Reconstruction Option: The option assumes that the existing pavement sections are totally obliterated, and new pavement sections are constructed on subgrade soil.

• Rehabilitation Option: The option assumes rehabilitation of the existing pavement sections by removing the upper part of existing pavement, and new sections are constructed on the remaining HMA or PCC.

The recommended flexible pavement design sections are summarized below:

Table 2 - Total Reconstruction Option

Facility Design

TI

(20 Yrs.)

Boring No.

Existing Pavement Sections Full Depth Option HMA & AB Option

HMA Thickness (Inches)

Concrete Thickness

PCC (Inches)

Full Depth HMA (feet)

HMA

(feet)

AB (Cl 2) (feet)

Overweight Vehicle Route

11.5

BEMB-1 15± --

1.10 0.60 1.10

BEMB-2

(Boring is away from travel lane) --

YD-1 9-1/2± --

YD-2 14-1/2± --

BEMB-3

(No existing pavement in the area) --

YD-3

(No existing pavement in the area) --

YD-4

(No existing pavement in the area) --

Embarcadero West

10.5 -- -- -- 1.00 0.55 0.95

10.0 -- -- -- 0.95 0.55 0.85

7.0 -- -- -- 0.65 0.35 0.55

Market St 12.5 BMKT-1 4-1/4± 5-3/4± 1.20 0.65 1.20

Martin Luther King Jr. Way

13.0 BMLK-1 9± 6± 1.25 0.70 1.20

Jefferson St 9.0 -- -- -- 0.85 0.45 0.80

Clay St 8.0 BC-1 4± 5± 0.75 0.40 0.70

Washington St 7.5 BWash-1 5± 5± 0.70 0.40 0.60

Broadway 8.5 BB-1 4-3/4± 9± 0.80 0.45 0.70

Franklin St 7.5 BF-1 5-3/4± 6± 0.70 0.40 0.60

Webester St 9.0 BWeb-1 4± 7± 0.85 0.45 0.80

Oak St 9.5 BO-1 16-1/2± -- 0.90 0.50 0.85

Note: Design R-Value = 40 HMA: Hot Mix Asphalt (Type A) PCC: Portland Cement Concrete AB: Aggregate Base (Class 2)

Table 3 - Rehabilitation Option

Facility Design

TI

(20 Yrs.)

Boring No.

Existing Pavement Sections

New HMA over Existing PCC or New HMA over Existing HMA Sections HMA Thickness

(Inches)

Concrete Thickness

PCC (Inches)

Overweight Vehicle Route

11.5

BEMB-1 15± -- Remove 0.95’ Existing HMA & Replace with 0.95’ New HMA

(Existing HMA thickness may be variable.

When existing HMA is less than 0.95’, use 1.10’ New Full Depth HMA on prepared subgrade. Exact limits to be determined in the field.)

BEMB-2

(Boring is away from travel lane) --

YD-1 9-1/2± --

YD-2 14-1/2± --

BEMB-3

(No existing pavement in the area) -- Use 0.60’ HMA over 0.95’ AB (New construction for areas without existing pavement)

YD-3

(No existing pavement in the area) --

YD-4

(No existing pavement in the area) --

Embarcadero West

10.5 -- -- -- Use 0.55’ HMA over 0.95’ AB

(new construction)

10.0 -- -- -- Use 0.55’ HMA over 0.85’ AB

(new construction)

7.0 -- -- -- Use 0.35’ HMA over 0.55’ AB

(new construction)

Market St 12.5 BMKT-1 4-1/4± 5-3/4± 0.85’ HMA & paving interlayer over existing PCC section

Martin Luther King Jr. Way

13.0 BMLK-1 9± 6±

0.90’ HMA & paving interlayer over existing PCC section

Jefferson St 9.0 -- -- -- 0.50’ HMA & paving interlayer over

Existing PCC section

Clay St 8.0 BC-1 4± 5± 0.50’ HMA & paving interlayer over existing PCC section

Washington St 7.5 BWash-1 5± 5± 0.50’ HMA & paving interlayer over existing PCC section

Broadway 8.5 BB-1 4-3/4± 9± 0.50’ HMA & paving interlayer over existing PCC section

Franklin St 7.5 BF-1 5-3/4± 6± 0.50’ HMA & paving interlayer over existing PCC section

Webester St 9.0 BWeb-1 4± 7± 0.50’ HMA & paving interlayer over

Existing PCC section

Oak St 9.5 BO-1 16-1/2± -- Remove 0.60’ Existing HMA & Replace with 0.60’ New HMA

Note: Design R-Value = 40 HMA: Hot Mix Asphalt (Type A) PCC: Portland Cement Concrete AB: Aggregate Base (Class 2) Recommend Min. 0.50’ HMA & Paving Interlayer over Existing PCC Pavement Interlayer: Tensar GlasGrid (over 1” leveling HMA course on existing PCC)

It is recommended that the pavement subgrade be scarified to a depth of at least 6 inches and moisture conditioned to 2% to 3% over optimum moisture content and re-compacted to at least 95% relative compaction per project specifications.

Reclaimed Asphalt Pavement. A portion of Type A HMA can be replaced by Reclaimed

Asphalt Pavement (RAP) in flexible pavement design for the Project. The RAP is specified in Section 39 2.02A “Asphalt Concrete” of the Caltrans Standard Specifications (2023).

According to the Caltrans specifications, RAP can substitute for part of the virgin aggregate in a quantity up to 25 percent of the aggregate blend. For Type A HMA using

RAP, the maximum allowed binder replacement is 25.0 percent in the upper 0.2 feet exclusive of open grade friction course (OGFC) and 40.0 percent below. The Caltrans

Standard Specifications should be referred to for preparation of Type A HMA using RAP.

Rigid Pavement Sections. We understand that there are some common shared street areas along Embarcadero West that will be using rigid concrete pavements. For these areas, we referred to AASHTO guidelines for low-volume roads using Portland Cement

Concrete (PCC). The recommended pavement sections consist of 7.5” PCC over 12”

Aggregate Base (Class 2).

Grading

It is recommended that the pavement subgrade be scarified to a depth of at least 6 inches and moisture conditioned to within approximately 2% to 3% of optimum moisture content and compacted to at least 95% relative compaction per ASTM D1557.

Any fill materials imported to the project site should be non-expansive, relatively granular material having a Plasticity Index (PI) of less than 15 and a minimum R-value of 40. The maximum particle size of fill material should not be greater than 3 inches in largest dimension. It should also be non-corrosive, free of deleterious material and should be reviewed by the Geotechnical

Engineer.

Where wet subgrade conditions are encountered, subgrade pumping may be observed during earthwork, and mobility of equipment and obtaining subgrade compaction requirements may also be difficult. Such subgrade soils may require reworking, aeration, or over-excavation and replacement with dry granular fill to facilitate earthwork construction. Geogrid or other geotextiles may also be considered to stabilize the subgrade.

Existing Soil and Groundwater Contamination.

Phase II soil testing was performed by Baseline Environmental Consulting (December 12, 2024).

The Baseline report is attached in Appendix E of the Geotechnical Memo (Parikh, March 12, 2025). Refer to the Baseline report for details. Per Baseline report, the shallow soils in the vicinity of Boring BEMB-2, located on Embarcadero West between Market Street and container yard, have analytical results exceed the construction workers ESLs, commercial/industrial ESLs, and

California and federal hazardous waste criteria due to elevated concentrations of metals. The boring is located adjacent to Radius Recycling (former Schnitzer Steel) near Adeline Street which has been operated as a metal recycling facility since 1961. The Radius Recycling facility is currently under active regulatory oversight from the DTSC and Regional Water Board for soil and groundwater contamination.

Limitations

Due to practical limitations inherent in geotechnical investigations, it is neither uncommon to encounter unforeseen variations in the soil, groundwater, and pavement conditions during construction nor is it practical to determine all variations during an acceptable exploration program.

Please be advised that we provide a professional service and that our conclusions are professional opinions only. All work done and all recommendations made are in accordance with generally accepted geotechnical engineering principles and practices.