Sacramento City Council
October 21, 2025

City of Sacramento
City Council - 5PM Report
915 I Street Sacramento, CA 95814
www.cityofsacramento.org
File ID: 2025-01648 10/21/2025
Accepting SAFCA's Urban Level of Flood Protection Reports (LR25-006) File ID: 2025-01648
Location: Citywide
Recommendation: Adopt: 1) a Resolution accepting the Sacramento Area Flood Control Agency’s 2025 Urban Level of Flood Protection Adequate Progress Annual Report; and 2) a Resolution acting as the land-use agency for the City of Sacramento accepting evidence in support of a ULOP Finding of 200-year flood protection for the American River North, American River South, and Robla-Arcade Levee Systems.

Contact: Remi Mendoza, Long Range Planning Manager, (916) 808-5003, [email protected], Community Development Department; Neal Joyce, Supervising Engineer, (916) 808-1461, [email protected], Department of Utilities Presenter: None
Attachments:
1-Description/Analysis
2-Background
3-SB 639 Overview
4-Resolution - ULOP Adequate Progress Annual Report
5-Exhibit A - SAFCA’s 2025 Adequate Progress Annual Report 6-Resolution accepting ULOP Engineer’s Reports
7-Exhibit A - American River North ULOP Engineer’s Report 8-Exhibit B - American River South ULOP Engineer’s Report 9-Exhibit C - Robla-Arcade ULOP Engineer’s Report
Description/Analysis
Issue Detail: On June 21, 2016, the City Council adopted a resolution accepting the Sacramento Area Flood Control Agency’s (SAFCA) Urban Level of Flood Protection (ULOP) Plan, prepared pursuant to Senate Bill 5 of 2007 (SB 5) and related legislation. The Plan identified flood improvement projects, cost estimates, anticipated funding sources, and a schedule to complete them by December 31, 2025, achieving 200-year flood protection for the city.

File ID: 2025-01648 10/21/2025
Since then, when considering development within a flood hazard zone, the City has relied on the 2016 ULOP Plan and SAFCA’s annual ULOP reports (2017 through 2024) as substantial evidence that SAFCA has made adequate progress toward construction of a 200-year flood protection system.

Over the past year, construction delays affected levee and pump station improvements in the Natomas and Beach Lake subareas. Under SB 5, ULOP was originally required to be attained by December 31, 2025. However, the City co-sponsored Senate Bill 639, which the Legislature passed to extend this deadline to December 31, 2030, for the Natomas and the Beach Lake subareas (Attachment 3-SB 639 overview). Accordingly, SAFCA has prepared the 2025 ULOP Adequate Progress Annual Report (Attachment 5), the ninth annual report, which continues to provide evidence supporting adequate progress findings for development approvals for these two areas of the City.

Meanwhile, SAFCA and the U.S. Army Corps of Engineers (USACE) have completed all major improvements to the American River North (Attachment 7), American River South (Attachment 8), and Robla-Arcade (Attachment 9) Levee Systems. The Dry Creek North levee system did not require additional improvements. SAFCA’s certification team has finalized ULOP Engineer’s Reports for these levee systems, providing substantial evidence for the City to make a ULOP Finding in its landuse decisions, confirming that these levee systems provide a 200-year Urban Level of Flood Protection.

On September 16, 2025, Council adopted a resolution accepting the Dry Creek North Levee System ULOP Engineer’s Report. Council action is now required to accept SAFCA’s 2025 ULOP Adequate Progress Annual Report and the ULOP Engineer’s Reports for the American River North, American River South, and Robla-Arcade levee systems, which will allow the City to make appropriate flood protection findings in its future land-use decisions.

Policy Considerations: The 2040 General Plan includes the following goals and policies related to flood protection:

GOAL Environmental Resources and Constraints (ERC-6) Protection of life and property from flooding hazards.

ERC-6.6 Flood Regulations. The City shall continue to regulate new development in accordance with State requirements for 200-year level of flood protection and federal requirements for 100-year level of flood protection.

Economic Impacts: Not applicable.

Environmental Considerations: Policies to achieve a 200-year level of flood protection were included in the 2040 General Plan and evaluated in the certified Master Environmental Impact Report. Acceptance of SAFCA’s 2025 Adequate Progress Annual Report and ULOP Engineer’s

File ID: 2025-01648 10/21/2025
Reports will enable the City to use these documents for future flood-related findings in compliance with state law. Acceptance of these documents constitutes an administrative action that will not result in direct or indirect physical changes in the environment, and the action is not a project that requires environmental review under the California Environmental Quality Act (CEQA). (CEQA Guidelines sections 15378(b)(5); 15060(c)(3).)
Sustainability: The proposed resolutions will reduce flood risk by strengthening the linkage between local land use planning decisions and flood management practices. These resolutions will also support the City’s efforts to promote urban infill and redevelopment.

Commission/Committee Action: Not applicable.

Rationale for Recommendation: Adoption of these resolutions is necessary to provide the substantial evidence required under State law for the City to make appropriate Urban Level of Flood Protection findings when approving future development projects.

Financial Considerations: Not applicable.

Background:

Urban Level of Flood Protection
In 2007 the California Legislature passed a package of six bills (SB 5, SB 17, AB 5, AB 70, AB 156, and AB 162) that mandated comprehensive planning for flood protection at the state and local levels.

The Central Valley Flood Protection Act of 2008 (enacted by SB 5) requires all cities and counties within the Sacramento-San Joaquin Valley to make findings related to an urban level of flood protection (ULOP) for urban and urbanizing lands located within a flood hazard zone. ULOP is defined as the level of flood protection necessary to withstand flooding that has a 1-in-200 chance of occurring in any given year.

Since July 1, 2016, state law has required cities and counties within the Central Valley to make one of the following findings before approving development agreements, tentative maps, discretionary permits, or ministerial permits for new residences:

1. Existing flood management facilities provide 200-year flood protection (Type 1);

2. Conditions are imposed that will provide 200-year flood protection (Type 2);

3. Adequate progress is being made toward 200-year flood protection (Type 3); or

4. The property is in an undetermined risk area.

File ID: 2025-01648 10/21/2025
The Sacramento Area Flood Control Agency (SAFCA), in coordination with State, Federal, and local partners, has been implementing a comprehensive program of flood risk reduction projects for the Sacramento region. This program includes levee, weir, and Folsom Dam improvements which, once complete, will meet the State requirement that urban areas in the Central Valley achieve at least a 200-year level of flood protection.

In 2016 SAFCA prepared the “Urban Level of Flood Protection Plan And Adequate Progress Baseline Report”, (ULOP Plan) that identified the improvements needed to achieve a 200-year level of flood protection, the funding sources, and a schedule for completion by December 31, 2025. On June 21, 2016, the City Council accepted this plan (Resolution No. 2016-0226).

Since then, the City has relied on SAFCA’s 2016 ULOP Plan and subsequent annual reports (2017 through 2024) as substantial evidence that SAFCA has been making adequate progress on the construction of a 200-year flood protection system (Type 3 finding).

Since major flood improvement projects have been completed, SAFCA’s certification team has prepared four Engineer’s Reports (Table-1 below) to demonstrate that portions of the levee systems protecting the City meet ULOP in accordance with the State’s Urban Levee Design Criteria (2012).

These reports will provide the substantial evidence required for the City to make Type I ULOP Findings when approving new development projects. The Engineer’s Reports for the two levee systems that require the SB 639 time extension will be provided in the timeline shown in Table-1.

On October 13, 2025, Senate Bill 639, co-sponsored by the City, was signed by the Governor (See Attachment 3 - SB 639 overview). This legislation extends the deadline for achieving ULOP from 2025 to 2030 for the Natomas and Beach Lake subareas, among other jurisdictions in the Central Valley. Accordingly, SAFCA has prepared the 2025 Adequate Progress Annual Report in place of the ULOP Engineer’s Reports for these two levee systems.

SAFCA’s certification team has finalized the ULOP Engineer’s Report for the Dry Creek North (accepted by Council on September 16, 2025), American River North, American River South, and

File ID: 2025-01648 10/21/2025
Robla-Arcade Levee Systems, included as Attachments 7 through 9. Staff recommends the Council adopt a Resolution accepting these three reports. Based on its findings, substantial evidence now exists for the City to make a Type 1 ULOP Finding in its land-use decisions, confirming that these levee systems provide a 200-year Urban Level of Flood Protection.

SAFCA’s 2025 ULOP Adequate Progress Annual Report
In order for the City to continue to rely on a “adequate progress finding” for the Natomas and Beach Lake subareas, the California Government Code § 65007(a)(5) requires the City to annually report to the Central Valley Flood Protection Board on its efforts towards completion of the 200-year flood protection system. Accordingly, SAFCA staff and consultants have prepared the 2025 ULOP Adequate Progress Annual Report for the City to fulfill Government Code requirements.

In summary the 2025 ULOP annual report demonstrates that:
· Over 100% of the revenue scheduled to be received has been appropriated and are currently being expended;
· Critical features of the flood protection system are under construction and progressing based upon the actual expenditures of the construction budget.

In most cases SAFCA ULOP projects are expected to be complete by 2025, except as follows:
· Natomas Reach A (Gateway Oaks Drive to Farm Road) - Completion of cutoff wall and seepage berms and relocation of utilities will delay completion of this levee improvement until 2026.
· Natomas Reaches F and G (Sankey Road to Natomas East Main Drainage Canal Pumping Station) - The United States Army Corps of Engineers (USACE) will not begin some elements of this work until 2027. The area affected is along the eastern subarea of the Natomas Basin, much of which is only projected to experience shallow flooding in a 200-year event and thus may be exempt from ULOP requirements.
· Magpie Creek - A residual floodplain will occur in the historic floodplain of Magpie Creek downstream of the Magpie Creek Diversion Channel (MCDC). Construction has not yet begun on a USACE project to reduce this residual floodplain. The City will need to consider this residual floodplain to determine what portion of it is exempt as shallow flooding and the appropriate finding required in the remainder of the area before making development approvals.

File ID: 2025-01648 10/21/2025
· Morrison Creek and Beach Lake North Levee - ULOP is dependent on construction of a short seepage berm and improvements to two pump stations. SAFCA expects construction on the berm and the Sweeney pump station to be substantially complete in 2025. The construction contract for Sump 89 is not expected to be complete until 2026.

SAFCA’s ULOP Engineer’s Reports for the American River North, American River South, and Robla-Arcade Levee Systems
Formally demonstrating that a 200-year ULOP has been achieved requires meeting the Urban Levee Design Criteria (ULDC), documented in an Engineer’s Report and reviewed by an Independent Panel of Experts (IPE). The City can then use these documents as substantial evidence in making findings for development proposals.

To support the City in meeting ULOP, SAFCA has provided the City with a package of ULOP Engineer’s Reports for four of the six levee systems. The Dry Creek North Levee (DCNL) Engineer’s Report was accepted by City Council on September 16, 2025. The American River North, American River South, and Robla-Arcade ULOP Engineer’s Reports have been completed and are being submitted to Council along with this staff report. These reports provide the technical and substantial evidence needed to make a Type 1 ULOP Finding when considering development approvals.

Next Steps and Future ULOP/ULDC Implementation Plans
SAFCA’s Engineer’s Reports provide substantial evidence documenting compliance with the Urban Levee Design Criteria (ULDC). The ULDC provides engineering criteria and guidance for the design, evaluation, operation, and maintenance of levees and floodwalls that provide an urban level of flood protection (i.e., 200-year level of flood protection).

To the extent that any exceptions to the criteria are identified, the City will adopt a plan that can be implemented for each exception (e.g., right-of-way, encroachments and penetrations) to meet the ULDC guidance. Per ULDC requirements, the City should adopt all implementation plans within one year after adopting the Engineer’s Report. The purpose of the implementation plans is to demonstrate progress to meet ULDC during the effective period of the ULOP finding for a duration of 20 years or until the finding is superseded whichever is sooner, provided that a periodic review of the finding is performed every 5 years. Looking ahead, these implementation plans will require significant and ongoing investments of staff time and financial resources. Future discussions with partners, including SAFCA, will be necessary to address the land use agencies’ responsibilities referenced in the reports. While SAFCA has not yet committed funding for these activities, the City will continue to work with SAFCA and other partners to fund any actions within the City’s jurisdiction necessary to clear the exceptions. Below is a summary of the exceptions included for each of the ULOP Engineer's Reports.

File ID: 2025-01648 10/21/2025
ULOP Engineer’s Report for the Robla-Arcade Levee System Exceptions to the ULDC criteria include:

1. Minimum Top of Levee - the required minimum elevation for the physical top of levee to provide a reasonable assurance of containing the Design Water Surface Elevation is not met along a portion of the Robla Creek South Levee between Station 6114+00 and 6118+20.

2. Soil Sampling, Testing and Logging - the required quantity and spacing of explorations were not in accordance with the standard for the Robla Creek South Levee, Natomas East Main Drainage Canal East Levee - Arcade Creek to Robla Creek and Arcade Creek North Levee.

3. Right-of-Way - a full 20-foot easement or fee title property is not present with some locations lacking any easement or property at the landside toe.

4. Penetrations - the structural evaluation of penetrations, age of pipes, permits not found, and inspection documentation were lacking.

5. Floodwalls, Retaining Walls and Closure Structures - for both Robla Creek South levee and Arcade Creek North levee the operation frequency for activating UPRR stoplog structures is five years versus the required one year.

ULOP Engineer’s Report for the American River North Levee System Exceptions to the ULDC criteria include:

1. Soil Sampling, Testing and Logging - the required quantity and spacing of explorations were not in accordance with the standard.

2. Right-of-Way - a full 20-foot wide easement or fee title property interest is not present, with some locations lacking any easement or property interest at the landside toe.

3. Encroachments - the evaluation indicates several Central Valley Flood Protection Board (CVFPB) encroachment permits were not found or are incomplete, and Title 23 compliance was lacking.

4. Penetrations - the structural evaluation, age of pipes, CVFPB permits not found, and inspection documentation reports were lacking.

File ID: 2025-01648 10/21/2025

5. Floodwalls, Retaining Walls and Closure Structures - for both Arcade Creek South Levee and American River North Levee the operation frequency for activating/exercising Union Pacific Railroad (UPRR) stoplog structures is five years versus the required one year.

ULOP Engineer’s Report for the American River South Levee System Exceptions to the ULDC criteria include:

1. Minimum Top of Levee (MTOL) - the required freeboard is slightly low along Sacramento River East Levee (SREL) in Old Town. The City of Sacramento has a flood fight plan which has been incorporated into the City of Sacramento Operations and Maintenance (O&M) documentation;

2. Soil Sampling, Testing and Logging - the required quantity and spacing of explorations were not in accordance with the standard;

3. Right-of-Way (ROW) - a full 20-foot flood easement or fee title property is not present with some locations lacking any easement or fee title property at the landside toe;

4. Encroachments - permits were either not found or incomplete, and Title 23 compliance was lacking; and

5. Penetrations - During the engineering evaluation, permits were not found, there was a lack of inspection documentation and concern on the structural evaluation of and the age of pipes.

The Engineer’s Reports support a ULOP finding for up to 20 years or until the finding is superseded, whichever is sooner. Periodic reviews of the finding must be completed every five years by a California-registered Professional Civil Engineer.

Attachment 3 - SB 639 Overview
Senate Bill 639 Zoning: Sacramento-San Joaquin Valley
Senate Bill 639 extended the deadline for the Natomas Basin and Beach Lake subareas (see blue areas on the map on the next page) to achieve the required urban level of flood protection (ULOP) from 2025 to 2030.

This targeted approach applies only to where additional time is needed for compliance, rather than applying citywide.

Certain areas in the counties of Sacramento, Sutter, Yuba and the City of Marysville were also included in this legislation. Two such legislative extensions have previously been adopted for the City of West Sacramento and Mossdale Tract in the City of Lathrop (San Joaquin County). However, previous deadline extensions limit the State’s liability by requiring the local agency that approves development in areas that do not have an urban level of flood protection to shoulder some liability for damages in the event of a major flood. Under SB 586, for example, the flood management agencies for Mossdale Tract and the City of West Sacramento are liable for their “fair and reasonable share of any property damage caused by a flood” that occurs between 2025 and 2040. This bill imposes similar liability on the cities of Marysville and Sacramento and the counties of Sacramento, Sutter, and Yuba.

Projects Requiring a Time Extension
SAFCA has been overseeing the efforts to improve the regional flood protection system. All the capital improvements required to handle the State-defined 200-year event have been completed except for the following:

1. A portion of the Natomas levee improvements
o Completion of the Reach A slurry cutoff wall extending from Interstate 80 to Sump 160

2. Sweeney Ranch Pump Station
o Modifications are required to meet current design requirements.

3. Sump 89 Outfall Replacement Project (City project)
o Modifications need to be made to meet current design standards.

Although it was anticipated that these projects would be completed by the end of 2025, due to construction delays it appears the current construction process may extend beyond the current deadline.

Potential Impacts Without Extension
Without a deadline extension, the City would have needed to impose cost-prohibitive conditions on most new development in the affected subareas, such as requiring buildings to be elevated 10 feet or more above ground level. These requirements would effectively halt or delay project approvals, creating major impacts on housing production and critical infrastructure.
 Natomas Subarea: Potential delays would have included a new hospital and residential projects totaling approximately 1,900 units.
 Beach Lake Subarea: Approximately 735 additional residential units could have also been affected.

RESOLUTION NO. 2025-
Adopted by the Sacramento City Council
Date Adopted
ACCEPTING THE SACRAMENTO AREA FLOOD CONTROL AGENCY 2025 URBAN LEVEL OF FLOOD

PROTECTION ADEQUATE PROGRESS ANNUAL REPORT

BACKGROUND
A. The Central Valley Flood Protection Act of 2008 (the “Act”) prohibits cities and counties, beginning July 1, 2016, from entering into development agreements, approving discretionary permits or ministerial permits that would result in the construction of a new residence, or approving tentative or parcel maps for areas located within a flood hazard zone unless the city or county makes one of the findings set forth in the legislation. (See Government Code sections 65865.5, 65962, and 66474.5.)
B. On March 1, 2016, the City Council adopted Ordinance No. 2016-0012, which makes various changes to the City Code to conform to the Act.

C. One of the Act’s required findings—the “adequate-progress finding”—allows development to proceed within a flood hazard zone if the city or county finds the local flood management agency has made adequate progress (as defined in Government Code section 65007) on the construction of a flood protection system that will result in flood protection equal to or greater than the urban level of flood protection (“ULOP”) in urban or urbanizing areas or the national Federal Emergency Management Agency (“FEMA”) standard of flood protection in nonurbanized areas intended to be protected by the system.

D. The California Department of Water Resources has declared that the adequate-progress finding must be based on the following: a report prepared by the applicable local flood management agency demonstrating adequate progress; a report prepared by a professional civil engineer that documents the data and analysis for demonstrating the property, development project, or subdivision will have an urban level of flood protection at the time when the flood protection system is completed; a report by an independent panel of experts on the review of the report prepared by the professional civil engineer; a response by the Professional Civil Engineer to the comments from the Independent Panel Of Experts; the most recent annual report prepared by local flood management agency that was submitted to the Central Valley Protection Board documenting the efforts in working toward completion of the flood protection system; and any additional data and information that cities or counties use to make the finding. (See California Department of Water Resources, Urban Level of Flood Protection Criteria, page 2-10.)
E. In 2016, consistent with these mandates, the City of Sacramento’s (City) local flood management agency—the Sacramento Area Flood Control Agency (SAFCA)—prepared documents to support the adequate-progress. On June 21, 2016, the City Council adopted Resolution No. 2016-0226 accepting SAFCA’s urban level of flood protection plan and adequate progress baseline report and adequate progress towards an urban level of flood protection engineer’s report.

F. On November 7, 2017, the City Council adopted Resolution No. 2017-0418 accepting SAFCA’s ULOP Adequate Progress Annual Report.

G. On November 20, 2018, the City Council adopted Resolution No. 2018-0445 accepting SAFCA’s ULOP Adequate Progress Annual Report.

H. On October 22, 2019, the City Council adopted Resolution No. 2019-0398 accepting SAFCA’s ULOP Adequate Progress Annual Report.

I. On October 13, 2020, the City Council adopted Resolution No. 2020-0326 accepting SAFCA’s ULOP Adequate Progress Annual Report.

J. On November 9, 2021, the City Council adopted Resolution No. 2021-0328 accepting SAFCA’s ULOP Adequate Progress Annual Report.

K. On October 11, 2022, the City Council adopted Resolution No. 2022-0313 accepting SAFCA’s ULOP Adequate Progress Annual Report.

L. On October 24, 2023, the City Council adopted Resolution No. 2023-0337 accepting SAFCA’s ULOP Adequate Progress Annual Report
M. On October 22, 2024, the City council adopted Resolution No. 2024-0311 accepting SAFCA’s 2024 ULOP Adequate Progress Annual Report
N. On October 13, 2025 the Legislature passed Senate Bill 639 which added Section 65962.4 of the Government Code which includes exceptions to the requirement that the Natomas and Beach Lake subareas of the City achieve an Urban Level of Flood Protection by 2025, which instead are required to achieve the Urban Level of Flood Protection by 2030.

O. In 2025, SAFCA has prepared the following to support the adequate progress finding: the Urban Level of Flood Protection Adequate Progress Annual Report. This document concludes that the levees that protect the Natomas and Beach Lake subareas of the City do not currently meet ULOP requirements, but SAFCA is meeting the State standards in demonstrating adequate progress towards achieving ULOP in urban or urbanizing areas or the national Federal Emergency Management Agency standard of flood protection in nonurbanized areas for property located within a flood hazard zone, intended to be protected by the system, by 2030.

P. On September 18, 2025, the SAFCA Board of Directors approved the ULOP Adequate Progress Annual Report for distribution to and use by the City and other agencies.

Q. The 2025 ULOP Adequate Progress Annual Report is an informational document that describes actions already being undertaken or planned by SAFCA and is not subject to the California Environmental Quality Act (CEQA). The environmental effects of the projects have been addressed at a program level by the 2016 Updated Local Funding Mechanisms for Sacramento Area Flood Control Improvements Subsequent Environmental Impact Report (EIR) and the underlying 2007 Program EIR. Policies to achieve a 200-year level of flood protection were included in the 2040 General Plan and evaluated in the certified Master Environmental Impact Report. The City’s acceptance of the SAFCA 2025 Urban Level of Flood Protection Adequate Progress Annual Report will enable the City to use that document and the ULOP and Engineer’s Report for flood related findings in compliance with State law. Acceptance of these documents constitutes an administrative action that will not result in direct or indirect physical changes in the environment, and the action is not a project that requires environmental review under the California Environmental Quality Act (CEQA). (CEQA Guidelines sections 15378(b)(5) and 15060(c)(3).) The need for additional CEQA compliance for individual projects will need to be considered at the time those projects are advanced.

BASED ON THE FACTS SET FORTH IN THE BACKGROUND, THE CITY COUNCIL RESOLVES AS FOLLOWS:

Section 1. The City Council accepts SAFCA’s 2025 ULOP Adequate Progress Annual Report, attached as Exhibit A and by this reference made a part of this resolution
Section 2. When considering development within a flood hazard zone in the Natomas and Beach Lake subareas, the City may rely on the 2025 ULOP Adequate Progress Annual Report, the ULOP and the Engineer’s report referenced in Resolution No. 2016-0226, as substantial evidence that SAFCA has made adequate progress (as defined in Government Code section 65007) on the construction of a flood protection system that will result in flood protection equal to or greater than the urban level of flood protection in urban or urbanizing areas or the national Federal Emergency Management Agency standard of flood protection in nonurbanized areas for property located within a flood hazard zone in the Natomas and Beach Lake subareas, intended to be protected by the system.

Table of Contents:

Exhibit A – SAFCA’s 2025 ULOP Adequate Progress Annual Report Office 916-874-7606
Fax 916-874-8289
1325 J Street, Suite 1700
Sacramento, CA 95814
September 24, 2025
Mr. Remi Mendoza Mr. Kevin Siu
Planning Division Department of Water Resources
City of Sacramento County of Sacramento
300 Richards Blvd, 3rd Floor 827 Seventh St, Room 301
Sacramento, CA 95811-0218 Sacramento, CA 95814
Mr. David Tomm
Public Works
County of Sutter
1130 Civic Center Blvd.

Yuba City, CA 95993
Subject: Urban Level of Flood Protection Adequate Progress Annual Report Dear Sirs:

Enclosed please find the Sacramento Area Flood Control Agency (SAFCA) 2025 Urban Level of Flood Protection Annual Report. As you know, Senate Bill (SB) 5, enacted in 2007, established 2025 as the year when an Urban Level of Flood Protection (ULOP) would need to be achieved by Central Valley communities before approving new development. In recognition of the Sacramento region’s progress and continuing work on major flood infrastructure improvements, SB 639 has been passed by the legislature and sent to the Governor. SB 639 will allow the region until 2030 to achieve ULOP. This report has been prepared under the assumption that SB 639 will become law.

This report identifies SAFCA’s progress on achieving the Urban Level of Flood Protection (ULOP) for State Plan of Flood Control (SPFC) facilities within our jurisdiction. On September 18, 2025, the SAFCA Board of Directors adopted Resolution No. 2025-095, approving distribution of this report. Because this progress is germane to the authorities vested in your agency, I encourage your agency to use the information provided herein in conjunction with your own data and judgment in reporting annual progress to the Central Valley Flood Protection Board.

SAFCA staff recommend a close reading of the enclosed report. No local or state delays in ULOP funding have occurred, and SAFCA, State, and Federal appropriations remain consistent with the ULOP Plan. SAFCA is working diligently with our state and federal partners to have major ULOP projects substantially complete by the proposed 2030 deadline and will continue to coordinate with you.

September 24, 2025
2025 ULOP Adequate Progress

SAFCA appreciates the opportunity to work with your agency on flood matters of mutual interest and looks forward to continued cooperation in achieving adequate progress in this and future years.

Sincerely,

Gary Bardini, P.E.

Deputy Executive Director (Interim)
Enclosure
cc (w/o enclosure):

Jason Campbell
Melanie Saucier
Mick Klasson
2025
Urban Level of Flood Protection
Annual Report
September 2025
1325 J Street Suite 1700
Sacramento, CA 95814
(916) 874-7606
2025 Urban Level of Flood Protection Annual Report 1

TABLE OF CONTENTS

1. Introduction ............................................................................................................................. 2

2. Planned scope, Schedule, and Cost ......................................................................................... 2

2.1 Project Scope.................................................................................................................... 3

2.2 Schedule ............................................................................................................................ 6

2.3 Costs, Revenues, and Appropriations.............................................................................. 12

3. Construction of Critical Features .......................................................................................... 12

4. Delays.................................................................................................................................... 15

5. References for Data Used...................................................................................................... 16

FIGURES
Figure 1: SAFCA Projects.............................................................................................................. 4 TABLES
Table 1: Timeline for Projects ........................................................................................................ 7 Table 2: ARCF Natomas Basin Project Status Detail..................................................................... 8 Table 3: ARCF 2016 Project Status Detail..................................................................................... 9 Table 4: Morrison Creek and ........................................................................................................ 10 Table 5: ULDC Engineer Evaluation Status................................................................................. 11 Table 6: Planned Expenditures ($millions, all sources)................................................................ 12 Table 7: Cumulative Planned Expenditures, Actual Appropriations and Actual Expenditures Through 2024-2025 ($millions, all sources)................................................................................. 13 2025 Urban Level of Flood Protection Annual Report 2

1. INTRODUCTION
California Government Code (CGC) Section 65007(a)(5) requires local agencies to “annually report to the Central Valley Flood Protection Board (CVFPB) on the efforts in working toward completion of the flood protection system.” State requirements are further described in the Urban Level of Flood Protection Criteria (ULOP Criteria; DWR, 2013).

This report describes Sacramento Area Flood Control Agency (SAFCA)’s efforts in improving the regional flood protection system over the fiscal year ending on June 30, 2025. Section 5 of the SAFCA Final Urban Level of Flood Protection Plan and Adequate Progress Baseline Report (ULOP Plan) noted that the majority of funding for SAFCA’s projects comes from State and Federal agencies over which SAFCA has no control (SAFCA, 2016).

This annual report only addresses the State Plan of Flood Control (SPFC) facilities. The local land use agencies, acting as floodplain managers, must consider this plan along with their own data to determine whether residual risks, including interior drainage and flood sources not managed by SPFC facilities, affect development projects to such a degree that the projects would be subject to flood protection findings under state law. If a land use agency is required to make a flood protection finding, the finding must be selected from one of those summarized below:
(1) Existing facilities provide ULOP in urban areas or meet the Federal Emergency Management Agency (FEMA) standard in nonurbanized areas; (2) Conditions on the project will protect it to the applicable standard; (3) The local flood management agency has made adequate progress on a flood system providing the applicable level of protection. For urban and urbanizing areas protected by project levees, ULOP will be achieved by 2025; or
(4) The property in an undetermined risk area has met ULOP based on substantial evidence in the record.

Development in areas dependent on flood risk reduction projects that are still under construction typically relies on the third finding listed above. In the event that ULOP has not been or cannot be achieved by 2025 under one of the possible findings, the local agency may not approve certain development activities within the affected area. This report is not intended to be a substitute for the independent judgment of the local agencies in adopting their findings.

2. PLANNED SCOPE, SCHEDULE, AND COST
CGC Section 65007(a)(1) requires the local flood management agency to report “the total project scope, schedule, and cost” of meeting ULOP with the agency’s flood protection system. This information was detailed in the ULOP Plan and is summarized here. 2025 Urban Level of Flood Protection Annual Report 3

2.1 Project Scope
The following projects, illustrated in Figure 1, will help attain the Urban Level of Flood Protection in SAFCA’s protected areas.

Folsom Dam Modifications – Folsom Dam Modifications include three related projects: the Folsom Joint Federal Project (JFP), the Folsom Dam Raise Project, and the Folsom Dam Water Control Manual Update.

The JFP is a joint project of the U.S. Bureau of Reclamation, U.S. Army Corps of Engineers (USACE), the CVFPB, the State Department of Water Resources (DWR), and SAFCA. The JFP created a new, gated auxiliary spillway on the east abutment of the dam, enabling the dam to be operated to accommodate a 200-year flood with a discharge of about 115,000 cubic feet per second (cfs) into the lower American River. The design flow accommodated by full use of the dam's river outlets and the auxiliary spillway is 160,000 cfs. The JFP is the only Folsom Dam Modifications project component required for ULOP in the streams in the SAFCA region.

The Folsom Dam Raise Project is increasing the height of the main dam, wing dams, and dikes that contain Folsom Reservoir. Congress has authorized raising the height of the wing dams and dikes by 3.5 feet. This will allow flood operators to store more flood water when forecasted inflows are decreasing (resulting in no imminent threat to the dam) and the additional storage is required to maintain releases from the dam at a level that can be safely contained by the downstream levee system. The project also includes improving the flood gates on the main dam to accommodate this additional reservoir elevation (USACE, 2017).

The Folsom Dam Water Control Manual (WCM) was updated in 2019 to optimize operations at the dam with the JFP improvements. Once the Folsom Dam Raise Project is completed, the manual will be adjusted again to reflect the increased reservoir storage capacity created by that project component.

American River Common Features (ARCF) 2014 Natomas Basin Project (formerly called the Natomas Basin USACE Project) – The Natomas levees are being improved in two phases.

Physical construction of the Natomas Levee Improvement Program (NLIP) Local Project, led by SAFCA, is complete and comprised eighteen miles of improvements to the Natomas Cross Canal south levee and the Sacramento River East Levee. The ARCF 2014 Natomas Basin Project consists of levee improvements around the remainder of the 42-mile Natomas Basin perimeter.

The USACE is planning and implementing the remaining elements (USACE, 2015):
• American River North Levee adjacent to Natomas Basin – widen 2 miles of levee in place and install a seepage cutoff wall through the levee and foundation. • Sacramento River East Levee adjacent to Natomas Basin – construct 5 miles of adjacent levee, 3.3 miles of deep seepage cutoff walls, and 4.3 miles of seepage berms • Pleasant Grove Creek Canal West Levee adjacent to Natomas Basin - Widen 3.3 miles of levee in place and install a soil bentonite cutoff wall. • Natomas East Main Drainage Canal (NEMDC)/Steelhead Creek West Levee – widen

12.8 miles of existing levee and install 10.7 miles of cutoff wall. 202
4 Urban Level of Flood Protection Annual Report4
Figure 1: SAFCA Projects
2024 Urban Level of Flood Protection Annual Report 5
• Natomas Cross Canal (NCC) South Levee – complete construction at gaps not remediated as part of NLIP at Bennett and Northern pumping plants and at the State Route 99 closure structure.

ARCF 2016 (formerly called American River Common Features General Reevaluation Report (GRR)) – The ARCF GRR was authorized by Congress in the Water Resources Development Act (WRDA) 2016 and is now known as ARCF 2016. ARCF 2016 features include additional bank protection along the American and Sacramento Rivers; levee height and seepage improvements along Arcade Creek; levee improvements, levee extension, purchase of flowage easements, and channel widening on the Magpie Creek Diversion Channel (MCDC); and changes to the Sacramento Weir and Bypass. On the Sacramento River East Levee downstream of the American River, ARCF 2016 is improving deficient sites with features like the following:
• Slurry cutoff walls to address levee seepage and stability • Rock bank protection to address erosion
• Geotextile slope stabilization to address levee stability • Slope flattening to address levee stability
• Levee raise to address freeboard deficiency
Bank protection along the American River consists of rock revetment with planting berms where feasible. In some cases “launchable rock” trenches, when undermined by erosion, are designed to release rocks onto the erosion surface.

Levee Accreditation Project (LAP) – The LAP is a locally-led construction project that advanced portions of the ARCF 2016 prior to congressional authorization and funding. The LAP includes slurry cutoff walls along the Arcade Creek North Levee, the NEMDC East Levee, and the Arcade Creek South Levee (AECOM, 2015). SAFCA also began design along the Sacramento River East Levee (SREL) downstream of the American River. SAFCA’s design project included stability berms, relief wells, relief well improvements, cutoff walls, and toe drains. The project also included erosion repairs. The USACE took over design efforts along the Sacramento River in 2018 and is leading construction. Structures and vegetation encroaching on the levees will be removed if necessary to meet National Flood Insurance Program (NFIP) standards and the State’s Urban Levee Design Criteria (ULDC).

The southernmost reach of the SREL at its junction with the North Beach Lake Levee was evaluated in 2018 (MBK, 2018). MBK recommended improving the North Beach Lake Levee and the Sacramento River East Levee downstream of the North Beach Lake Levee. The recommendations included raising the North Beach Lake Levee to meet ULDC requirements, possibly in conjunction with a riparian wind-wave buffer and DWR improvements to the levees of the McCormack-Williamson Tract. Improvements to two pump stations and construction of a short reach of seepage berm were also recommended. The McCormack-Williamson Tract Project has been completed by DWR.

South Sacramento County Streams Group (SSSG) Project – USACE was the lead agency on this completed project, which consisted of improvements to the North Beach Lake Levee, levees and 2025 Urban Level of Flood Protection Annual Report 6
channels along Morrison Creek and its tributaries in South Sacramento, including Florin Creek, Elder Creek, and Unionhouse Creek. Physical work is now complete.

Florin Creek Multi-Use Basin Project – In moderate and larger flood events, the completed Florin Creek Multi-Use Basin Project can store up to 30 acre-feet of Florin Creek flows at Florin Creek Park on the north bank of Florin Creek (ESA, 2014). It provides at least 100-year flood protection within its floodplain in conjunction with the Florin Creek capacity improvements constructed by USACE as part of the South Sacramento County Streams Group Project.

Non-Structural Actions – The state’s ULDC (DWR, 2012) are incorporated by reference in the ULOP Criteria and require many actions that are good practices for the effective operation and maintenance of levee systems to sustain system performance. These actions include such measures as engineering evaluation and documentation, development of security and safety plans, and other items. The non-structural actions and their necessity are described in greater detail in the Adequate Progress Engineer’s Report (MBK, 2016). Ongoing operation, maintenance, repair, and rehabilitation may be considered ongoing non-structural actions that to the extent required are funded by SAFCA and its land use agency and local maintaining agency partners. Progress on these actions is not reported here unless the actions are “critical features” under the meaning of CGC Section 65007(a)(3).

2.2 Schedule
Under the original ULOP legislation, which included Senate Bill 5 (2007), ULOP must be achieved by the year 2025 in order for land use agencies, in approving new development, to make a finding that adequate progress is being made on the construction of a flood protection system (CGC §65865.5, §65962, and §66474.5). That legislation would be amended by Senate Bill 639, which has been introduced in the 2025-2026 legislative session. Among other things, SB 639, as of its July 17, 2025 amendments, would extend the period for ULOP attainment to the year 2030 in the Beach Lake and Natomas subareas of the SAFCA region. During the interim in these areas, the land use agency would assume financial responsibility for flood damages suffered by new development unreasonably approved by the agency, if any.

Table 1 on the next page lists the schedule for SAFCA projects. Table 2 provides additional detail on the ARCF 2014 Natomas Basin Project, Table 3 provides additional detail on the ARCF 2016 Project, and Table 4 provides additional detail on the Morrison Creek and Beach Lake Levee Resiliency Project. Table 5 summarizes the status of engineering evaluations for the levee systems.
2025 Urban Level of Flood Protection Annual Report 7
Table 1: Timeline for Projects
Project
Natomas
Levee
System
Dry
Creek
Levee
System
Robla
Creek –
Arcade
Creek
Levee
System
American
River
North
Levee
System
American
River South
and
Sacramento
River East
Levee
System
South
Sacramento
Streams
Levee
System
Construction
Status
Folsom Dam
Modifications
–– JFP & its
WCM
JFP
required for
ULOP
Not
required
JFP
required for
ULOP
JFP
required
for ULOP
JFP required
for ULOP
JFP required
for ULOP
JFP and its
WCM
complete.

Folsom Dam
Modifications
–– Raise &
its WCM
Not
required for
ULOP
Not
required
for
ULOP
Not
required for
ULOP
Not
required
for ULOP
Not required
for ULOP
Not required
for ULOP
Not required
for ULOP
ARCF 2014
Natomas
Basin Project
Required
for ULOP
(Table 2)
Not
required
Not
required
Not
required
Not required Not required See detail in
Table 2
NLIP Local
Project
Required
for ULOP
Not
required
Not
required
Not
required
Not required Not required Complete
ARCF 2016
(elements
required for
200-year
protection)
Provides
resiliency
(lowers
water
surfaces)
Not
required
Provides
resiliency
Some
elements
required
for ULOP
(Table 3)
Some
elements
required for
ULOP
(Table 3)
Provides
resiliency
See detail in
Table 3
LAP Not
required
Not
required
Required
for ULOP
Required
for ULOP
Not required Not required Complete
SSSG Not
required
Not
required
Not
required
Not
required
Not required Site
specific*
Complete
Florin Creek
Multi-Use
Basin
Not
required
Not
required
Not
required
Not
required
Not required Site
specific*
Complete
Additional
South
Sacramento
SPFC
Project(s) at
North Beach
Lake Levee
Not
required
Not
required
Not
required
Not
required
Some
elements
required for
ULOP
(Table 4)
Not
Required
See detail in
Table 4
*This plan provides 200-year design flood risk reduction in the South Sacramento Streams area downstream of the Union Pacific Railroad (UPRR), subject to the evaluation of additional south Sacramento SPFC projects. Upstream of UPRR, the land use agency’s determination of whether ULOP is attained will depend on the specific site and development proposal as some areas of residual flooding over 3 feet deep remain. At some sites, the listed projects will help attain ULOP.
2025 Urban Level of Flood Protection Annual Report 8
Table 2: ARCF Natomas Basin Project Status Detail
Element Status
Elements
Required
for ULOP
ULOP Ready
for Engineer’s
Report*
Reach A
Gateway Oaks Dr
to Farm Rd
Cutoff wall work upstream of I-80 to be completed in 2025.

The full adjacent levee in this area has been delayed by the relocation of a gas pipeline, to be completed in 2026.

Drained seepage berm and levee reconstruction work under I-80 to be completed in 2026. Cutoff wall work from I-80 to City Sump 160 to be completed in 2025, with the full
adjacent levee in this area completed in 2026. Pumping
Plant 1B and 1A discharge pipe work, sump 160 discharge pipe work and drained stability berm from Sump 160 to
Gateway Oaks Drive to be finished in 2027.

All Complete by
2027
Reach B
San Juan Rd to
W. Elverta Rd
Levee construction complete. Pumping Plant #3 and I-5
window complete. Riverside Pumping Plant complete.

Elkhorn Pumping Plant to be complete in 2025. Riverside Pumping Plant and Elkhorn Pumping Plant discharge pipe
raises to be complete by 2027. Pumping Plant #5 work to begin in 2026 and be completed in 2027.

Levee. 2025 with
engineerapproved ULDC
exceptions. Fully
complete by
2027.

Reach C
W. Elverta Rd to
Sankey Rd
Levee construction completed by SAFCA. Pritchard
Pumping Plant (Phase #2) discharge pipe raise to begin
construction in 2026.

Levee. 2025 with ULDC
exceptions. Fully
complete by
2027.

Reach D
Sankey Rd to
Howsley Rd
Levee construction completed by SAFCA.

Highway 99 window work began in 2024 and is expected to be complete in 2025. Pumping Plant #4 construction began in 2021 and is pending connection to PG&E service for
completion.

Levee. 2025 with ULDC
exceptions. Fully
complete by
2027.

Reach E
Howsley Rd to
Sankey Rd
Levee construction began Spring 2023 and is expected to be complete in 2025.

All Complete by
2025**
Reaches F&G
Sankey Rd to
NEMDC
Pumping Station
Levee construction and slope improvements to start in 2027 and be completed in 2029 (2030 if landside slope hardening features aren’t contracted by USACE). SAFCA has acquired the necessary right-of-way for construction and is currently working on utility relocations. Pumping Plant #6 to begin Summer 2027.

All Construction
underway by
2027.***
Reach H
NEMDC
Pumping Station
to Northgate Blvd
Contract 1 - NEMDC Pump Station to Arden-Garden: Work
has been completed. Contract 2 - Arden-Garden to
Northgate: Landside levee slope flattening work and
installation of maintenance road to begin 2026.

Contract 1 2025 with ULDC
exceptions. Fully
complete by
2027.

Reach I
Northgate Blvd to
Gateway Oaks Dr
Contract 2: Landside levee improvements and installation of maintenance road to begin 2026.

Contract 1 2025 with ULDC
exceptions. Fully
complete by
2027.
*Status at the time of this report based on substantial completion of construction sufficient for an Engineer’s Report to show attainment of ULOP. SAFCA cannot control the schedule of projects led by other agencies. “Exceptions” are exceptions to the ULDC criteria justified by the Engineer’s Report and consistent with ULOP. **Construction is expected to be substantially complete by the end of 2025. Final completion may go into 2026 and documentation into 2027.
***The schedule for reaches F&G is contingent on continued full funding from the federal government and continued actions by the SAFCA Board of Directors authorizing necessary real estate purchases as well as the USACE constructing the landside slope hardening.
2025 Urban Level of Flood Protection Annual Report 9
Table 3: ARCF 2016 Project Status Detail
Element Status Elements Required
for ULOP
ULOP
Attainment*
Sacramento River
East Levee –
Seepage,
Stability, &
Overtopping
Contracts C1 and C2 complete.

Contract C3 complete.

SREL C4 under construction.

All Complete by
2025
Sacramento River
East Levee –
Erosion
Contract C1 complete. C2 to be
constructed in 2023 and 2024.

Only C1 and C2 are
required for ULOP.

Contracts C1
and C2
complete by
2025.

Magpie Creek
Levee Raise
Construction will begin after
2025.

The raise will
protect an existing
floodplain where
flood depths are
greater than 3 feet
and buildings cannot
be feasibly elevated.

Attainment
will be after
2025.

North Area
Streams
Work on Arcade Creek is
complete. A short reach of the
Robla Creek South Levee does
not meet freeboard but flooding
in the area protected is below the
applicable 3-foot flood depth
criterion LOC-1 in the ULOP
Criteria.

All Complete. An
isolated
floodplain
with
insufficient
freeboard on
Robla Creek
South levee
may remain.

American River –
Erosion
Contracts C1 and C2 complete.

C3A – under construction in 2025
Only C1 and C2 are
required for ULOP.

Complete by
2025.

Sources: USACE 2022c, USACE 2022d, SAFCA
*Attainment status reflects the most current information at the time of this report. These estimates are subject to change. SAFCA cannot control the schedule of projects led by other agencies. 2025 Urban Level of Flood Protection Annual Report 10
Table 4: Morrison Creek and
Beach Lake Levee Resiliency Project Status Detail
Element Status
Elements
Required for
ULOP
ULOP
Attainment*
Seepage berm
and Pump Station
Improvements
SAFCA is building a short length of
seepage berm and reconstructing the
Sweeney Ranch pump station in
2025. The City of Sacramento has
awarded a construction contract for
Sump 89 that is expected to be
completed in 2026.

Required for
ULOP.

ULOP attainment
expected in 2026.

Source: SAFCA
*Attainment status reflects the most current information at the time of this report. These estimates are subject to change. SAFCA cannot control the schedule of projects led by other agencies. 2025 Urban Level of Flood Protection Annual Report 11
Table 5: ULDC Engineer Evaluation Status
Levee System Status Exceptions or Limitations
Natomas Levee System The evaluation is
planned for
completion by the
end of 2026.

Land Use Agency Implementation Plans
required for Right-of-Way, Penetrations and
Encroachments.

A residual 200-year floodplain may exist in the
lowest part of the north-central basin that will
be partly addressed by work on Reaches F and
G after 2027. Land use agencies will need to
map the area with a depth greater than three
feet in order to make findings for development
approvals in the affected areas.

Dry Creek North Levee
System
Complete None.

Robla Creek – Arcade
Creek Levee System
Complete Land Use Agency Implementation Plans
required for Right-of-Way, Penetrations and
Encroachments.

Residual 100- and 200-year floodplains exist
along historic Magpie Creek west of Raley
Boulevard in the area west of the Magpie Creek
Diversion Channel levee. Land use agencies
will need to map the area with a depth greater
than three feet and a contributing watershed of
ten or more square miles in order to make
findings for development approvals in the
affected area.

American River North
Levee System
Complete Land Use Agency Implementation Plans
required for Right-of-Way, Penetrations and
Encroachments.

American River South
and Sacramento River
East Levee System
Complete Land Use Agency Implementation Plans
required for Right-of-Way, Penetrations and
Encroachments.

Morrison Creek/North
Beach Lake Levee (part
of South Sacramento
Streams Levee System)
Construction on
Sump 89 is
planned for
completion in
2026 and
evaluation in the
first half of 2027.

Land Use Agency Implementation Plans
required for Right-of-Way, Penetrations and
Encroachments.
2025 Urban Level of Flood Protection Annual Report 12

2.3 Costs, Revenues, and Appropriations
System improvement costs, or planned expenditures, were shown in the ULOP Plan as required by CGC Section 65007(a)(1). Revenues to fund those expenditures were also identified pursuant to CGC 65007(a)(2)(A). Table 6 shows combined planned expenditures for all agencies along with actual expenditures. Table 6 demonstrates that expenditures are keeping pace with or exceeding the planned level.

Table 6: Planned Expenditures ($millions, all sources)
Fiscal
Year
2015-
2016
2016-
2017
2017-
2018
2018-
2019
2019-
2020
2020-
2021
2021-
2022
2022-
2023
2023-
2024
2024-
2025
2025-
2026
Original
ULOP
Plan
Costs*
$171.6 $141.0 $111.3 $149.9 $125.5 $125.5 $163.6 $126.6 $126.6 $108.8 $53.9 Actual
Spent** $167.8 $114.3 $123.1 $171.3 $428.3 $644.5 $608.3 $242.7 $146.9 $92.4 N/A * Original ULOP Plan Costs include capital projects and levee modernization. Values in the 2016 ULOP Plan included system operations and maintenance (O&M) which are no longer shown. ** Actual expenditures are SAFCA actuals plus estimates of other agency expenditures based on funding agreements and/or the progress of the projects.

SAFCA, State, and Federal appropriations also remain consistent with the plan, as shown in Table 7: Cumulative Planned Expenditures, Actual Appropriations and Actual Expenditures Through 2024-2025 ($millions, all sources). CGC Section 65007(a)(2)(A) specifies that adequate progress means that 90 percent of the revenues scheduled to be received by that year have been appropriated and are currently being expended. Table 7 shows this requirement has been met with over 100 percent of scheduled revenues appropriated to date. The Federal and State appropriations reflect Congressional authorizations and executed funding agreements. SAFCA appropriations reflect past spending and current year appropriations. Section 3 of this report will describe how these appropriations are being expended.

3. CONSTRUCTION OF CRITICAL FEATURES
Pursuant to Government Code Section 65007(a)(3), adequate progress on construction of a flood protection system means that critical features of the system are under construction and progress is indicated by the expenditure of the budgeted construction funds. The preceding section documented that SAFCA expenditures are on track. This section provides a brief summary of the construction progress in each of the SAFCA protected areas. This report does not distinguish between expenditures for physical construction and those for other project-related activities like planning and design because the cash flow and planned expenditures in the ULOP Plan do not provide line items for construction alone; and the pre-construction work is a planned and necessary component of ULOP Plan implementation.
2025 Urban Level of Flood Protection Annual Report 13
Table 7: Cumulative Planned Expenditures, Actual Appropriations and Actual Expenditures Through 2024-2025 ($millions, all sources) Agency
Planned
Expenditures*
Actual
Appropriations**
Actual
Expenditures***
Percent
Appropriated
Versus Planned
Expenditures****
Federal $1,573.8 $2,736.8 $2,835.4 >100%
State $885.7 $1,056.6 $881.7 99.5%
Local $47.5 $47.4 $47.5 100%
SAFCA $396.9 $525.8 $540.2 >100%
Total $2,903.9 $4,366.5 $4,212.4 >100%
Notes:
*Planned expenses are the planned cumulative capital project expenses from Fiscal Year 2006-2007 through Fiscal Year 20242024-2025 as shown in the 2016 ULOP report. ** For purposes of this report, State appropriations represent the amount of executed State funding agreements with SAFCA. Amounts listed as SAFCA appropriations include past spending plus current year appropriations to avoid double-counting unspent appropriations from prior years. *** Actual expenditures are SAFCA actuals plus estimates of other agency expenditures based on funding agreements and/or the progress of the projects. **** The federal and total percent appropriated exceed 100% because the federal Bipartisan Budget Act of 2018 (Public Law 115-123) included full funding for the American River Common Features and Folsom Dam Raise.

All Protected Areas – All of the SAFCA protected basins benefit from the Folsom Dam Modifications. The first element of the modifications, the JFP, was largely completed in 2016.

Since then the completed project has been turned over to the U.S. Bureau of Reclamation and the Water Control Manual has been formally executed.

Natomas – SAFCA has largely completed its Natomas Levee Improvement Program (NLIP), which improved levees on the north and part of the west perimeter of the basin. The ARCF 2014 Natomas Basin Project is improving the basin’s remaining levees and perimeter drainage infrastructure, which are referred to in sequential reaches starting with Reach A from the American River confluence to San Juan Road and moving around the basin in a clockwise direction (USACE, 2022b). Levee construction is underway in Reach A on the SREL. Work on the drained stability berm from City Sump 160 to Gateway Oaks Drive will likely be completed in 2026. Work at the RD 1000 Pump Plant 1B should be completed in 2026. ULOP conformance in 2025 or 2026 will require obtaining a set of record drawings and engineer confirmation that the interim construction condition meets ULDC. USACE Reach B (along the SREL north of San Juan Road to Elverta Road) construction is essentially complete. Construction of Riverside Pumping Plant in this reach is complete. Construction of Elkhorn Pumping Plant in this reach is underway and is expected to be complete in 2025. Riverside Pumping Plant and Elkhorn Pumping Plant discharge pipe raises are scheduled to begin construction in 2026. Levee construction is essentially complete in Reach C (from Elverta Road to the Natomas Cross Canal) with Pritchard Pumping Plant Phase 2 discharge pipe scheduled to begin construction in 2026.

Levee construction in Reach D (Natomas Cross Canal South Levee) is complete except for cutoff wall work at Highway 99, which is anticipated to be complete by end of 2025. Work continues at 2025 Urban Level of Flood Protection Annual Report 14
Pumping Plant 4, where the remaining electrical equipment is expected to be installed by the end of 2025. The construction contract for Reach E (Pleasant Grove Creek Canal West Levee) was awarded in April 2023 and will be completed in 2025. Reaches F and G (Natomas East Main Drainage Canal West Levee) are currently being designed. Construction award is expected in 2027 and completion in 2029. A ULDC exception for freeboard deficiency may be required in the northern part of Reach F and would require slope hardening features. At this point, it’s unclear of the extent of this slope hardening that will be constructed by the USACE. If not fully constructed by the USACE, then SAFCA and DWR will need to design and construct, and completion would occur in 2030. Seepage cutoff walls, levee slope flattening, and improvements to two stormwater pumping stations are essentially complete on USACE Reach H (along the NEMDC West Levee from NEMDC Pumping Station [located just north of the confluence with Dry Creek] to the Arden Garden Connector). Reach I Contract 1 (American River North Levee west of Northgate Boulevard to Gateway Oaks Drive) included a blanket drain constructed under the I-5 overpass and a cutoff wall to the east and west along the Garden Highway. Both of these components are now complete. Reach I Contract 2 will begin construction in 2026 and be completed in 2027. Natomas benefits from the Folsom Dam Modifications project components discussed above, but these are not required to meet ULOP.

Dry Creek North Levee System – No construction projects are required for the Dry Creek North Levee to meet ULOP.

Robla Creek South Levee, NEMDC East Levee, and Arcade Creek North Levee – In 2017, fourteen relief wells were constructed along the Arcade Creek North Levee. Construction of cutoff walls under SAFCA construction Contract 4355 is now complete. Improvements to the Magpie Creek Diversion Channel as part of ARCF 2016 are known as the Magpie Creek Project.

The Magpie Creek Project is being designed now and will be constructed after 2025. A short reach of the Robla Creek south levee downstream of Dry Creek Road does not meet freeboard requirements, but this deficiency only affects a small area and flooding would be less than three feet deep. SAFCA completed a stability berm along the NEMDC East Levee along UPRR in 2025.

American River North Levee – Cutoff walls along the Arcade Creek South Levee and NEMDC East Levee and were completed by USACE in 2015. SAFCA completed a stability berm along the NEMDC East Levee at Arcade Creek in 2025.

American River South and Sacramento River East Levee downstream of the American River – Structural improvements to the Sacramento River East Levee downstream of the American River have been designed, and USACE has retained a construction contractor. Contract 1 included work in the Pocket area and a seepage berm near Front Street and Miller Park that is now complete (USACE, 2022a). The second contract along the Sacramento River East Levee in the Pocket area, includes cutoff wall construction, now complete, and relief wells to address seepage and stability issues. Construction Contract 3 is complete. SREL Contract 4 was awarded in 2023 and was completed in 2024.

Work is also planned north of Miller Park near U.S. Highway 50. Encroachments in the construction footprint were removed by SAFCA. Under its “levee modernization” project, 2025 Urban Level of Flood Protection Annual Report 15
SAFCA acquired a property adjoining the levee and removed encroachments on the property in preparation to splitting the portion of the property under the flood easement from the landside remainder and conveying fee title to the levee area to the State or City. A voluntary encroachment removal program has been initiated for other affected properties. On the North Beach Lake Levee, SAFCA is building a short length of seepage berm and reconstructing the Sweeney Ranch pump station in 2025. The City of Sacramento has awarded a construction contract for Sump 89 that is expected to be completed in 2026. In 2019, SAFCA also constructed an oak woodland mitigation project to provide a wind-wave buffer for the levee.

South Sacramento Streams Group – Upstream of the UPRR, construction is complete on the Florin Creek channel improvements and the Florin Creek Multi-Use Basin project. This project was intended to meet FEMA 100-year criteria but was not designed to meet ULDC requirements.

The Federal Emergency Management Agency (FEMA) issued a LOMR for that work that became effective on March 25, 2019. The City or County may choose to investigate whether some areas where 200-year flood depths are below 3 feet may be newly eligible for a ULOP finding based on the project providing 100-year protection.

4. DELAYS
Adequate progress towards achieving an Urban Level of Flood Protection means, according to Government Code Section 65007(a)(4), that “the city or county has not been responsible for a significant delay,” among other things. In SAFCA’s flood protected areas, this standard has been achieved. As Table 7 demonstrated, to date local agencies have exceeded 100% of their planned expenditures for flood protection.

The ULOP Criteria recommend that annual progress reports address “any delay in State funding appropriation consistent with an agreement between a State agency and a local flood management agency.” As demonstrated earlier, State appropriations to date exceed their planned level.

This report shows that upon the close of the 2025 construction season, there will be certain areas within the SAFCA jurisdiction where ULOP may not be attained or may be attained with specified exceptions. As of this writing, the legislature is considering SB 639, which would extend the deadline for ULOP attainment in the Natomas and Beach Lake subareas until 2030. In the event SB 639 does not pass, development in affected parts of those subareas will be subject to the limitations enacted by Senate Bill 5 in 2007.
2025 Urban Level of Flood Protection Annual Report 16

5. REFERENCES FOR DATA USED
AECOM. 2015. Draft Environmental Impact Report. North Sacramento Streams, Sacramento River East Levee, Lower American River, and Related Flood Improvements Project. State Clearinghouse No. 2008072060. Prepared for Sacramento Area Flood Control Agency. March.

DOF (California Department of Finance). 2019. State budget detail. Department of Water Resources. May Revise. Available at: http://www.ebudget.ca.gov/2019- 20/pdf/GovernorsBudget/3000/3860.pdf. Accessed 5/31/2019.

DWR (California Department of Water Resources). 2012. Urban Levee Design Criteria. May.

DWR. 2013. Urban Level of Flood Protection Criteria. November.

DWR. 2017. Central Valley Flood Protection Plan 2017 Update. August.

EPS (Economic & Planning Systems, Inc.). 2016. Sacramento Area Flood Control Agency Development Impact Fee Program 2016 Update. Prepared for Sacramento Area flood Control Agency (SAFCA). October.

ESA, 2014. Florin Creek Multi-Use Basin Project. Initial Study with Intent to Adopt a Mitigated Negative Declaration. State Clearinghouse No. 2014032030. Prepared for Sacramento Area Flood Control Agency. March.

MBK (MBK Engineers). 2016. Sacramento Area Flood Control Agency Adequate Progress Towards an Urban Level of Flood Protection Engineer’s Report. Prepared for SAFCA.

MBK. 2018. Status of ULDC Evaluation of the Beach Lake Levee. Memo to Pete Ghelfi, SAFCA, from Ric Reinhardt, P.E., MBK Engineers.

SAFCA. 2016. Sacramento Area Flood Control Agency Final Urban Level of Flood Protection Plan and Adequate Progress Baseline Report. Prepared for the City of Sacramento and parts of Sacramento and Sutter counties. June 10.

SAFCA. 2017. 2017 Urban Level of Flood Protection Adequate Progress Annual Report.

Prepared for the City of Sacramento and parts of Sacramento and Sutter counties. August 9.

USACE (United States Army Corps of Engineers). 2015. American River Common Features General Reevaluation Report. Final Report. Sacramento District. December. Available at:
http://www.spk.usace.army.mil/Portals/12/documents/civil_works/CommonFeatures/Final_ARC F_GRR_Jan2016.pdf. Accessed June 3, 2016.

USACE. 2017. Record of Decision. Folsom Dam Raise Project. Placer, Sacramento, and El Dorado Counties, California. December 18. Available at:
https://www.spk.usace.army.mil/Portals/12/documents/civil_works/JFP/Raise/ROD_FolsomDam _Raise_Signed_18Dec2017.pdf?ver=2018-03-09-124144-317. Accessed 7/31/2019. 2025 Urban Level of Flood Protection Annual Report 17
USACE. 2022a. Sacramento Levee upgrades. Available at:
https://www.spk.usace.army.mil/Missions/Civil-Works/Sacramento-Levee-Upgrades/. Accessed 5/18/2022.

USACE. 2022b. Natomas Basin. Available at: https://www.spk.usace.army.mil/natomas/.

Accessed 5/18/2022.

USACE. 2022c. Unpublished schedule information on American River Common Features 2016.

May 19.

USACE. 2022d. Unpublished schedule information on Lower American River erosion contracts.

June 17.

WSP Parsons Brinckerhoff (PB). 2016. Engineer’s Report. Sacramento Area Flood Control Agency. Consolidated Capital Assessment District No. 2. June 13.

RESOLUTION NO. 2025-
Adopted by the Sacramento City Council
Date Adopted
ACCEPTING THE SACRAMENTO AREA FLOOD CONTROL AGENCY’S
ULOP ENGINEER’S REPORTS FOR THE AMERICAN RIVER NORTH,

AMERICAN RIVER SOUTH, AND ROBLA-ARCADE LEVEE SYSTEMS IN SUPPORT OF A FINDING OF 200-YEAR URBAN LEVEL OF FLOOD

PROTECTION

BACKGROUND
A. The Central Valley Flood Protection Act of 2008 (the “Act”) prohibits cities and counties, beginning July 1, 2016, from entering into development agreements, approving discretionary permits or ministerial permits that would result in the construction of a new residence, or approving tentative or parcel maps for areas located within a flood hazard zone unless the city or county makes one of the findings set forth in the legislation. (See Government Code sections 65865.5, 65962, and 66474.5.)
B. On March 1, 2016, the city council adopted Ordinance No. 2016-0012, which makes various changes to the city code to conform to the Act.

C. SB 5 restricted development beyond July 2, 2016 unless a land use agency makes one of the following findings: (1) there exists a 200-year Urban Level of Flood Protection (ULOP) (Type I Finding), (2) conditions are imposed on a development project to achieve 200-year protection (Type 2 Finding), (3) adequate progress is being made toward 200-year protection by December 31, 2025 (Type 3 Finding), (4) the property is in an undetermined risk area (Type 4 Finding) and these correspond with City Code Section 17.810.

D. The Sacramento Flood Control Agency’s (SAFCA’s), substantial evidence of Urban Level of Design Criteria (ULDC) compliance for the American River North, American River South, and Robla-Arcade Levee Improvement Projects will support a Type I ULOP Finding made by the City, when required as part of approval of discretionary or ministerial permits which corresponds with City code Section 17.810.

E. The substantial evidence developed by SAFCA in support of Type I ULOP Findings are described in certified Engineer’s Reports by SAFCA which are attached as Exhibit A, B, and C.

BASED ON THE FACTS SET FORTH IN THE BACKGROUND, THE CITY COUNCIL RESOLVES AS FOLLOWS:

Section 1. The city council accepts the substantial evidence provided by SAFCA in support of a Type I ULOP Finding that the facilities of the American River North, American River South, and RoblaArcade Levee Systems provide an urban level of flood protection as defined by the State of California’s Urban Levee Design Criteria.

Table of Contents:

Exhibit A – SAFCA’s ULOP Engineer’s Report for the American River North Levee System
Exhibit B - SAFCA’s ULOP Engineer’s Report for the American River South Levee System
Exhibit C - SAFCA’s ULOP Engineer’s Report for the Robla-Arcade Levee System

URBAN LEVEL OF FLOOD PROTECTION
ENGINEER’S REPORT

FOR THE

AMERICAN RIVER NORTH LEVEE SYSTEM
OCTOBER 2024
FINAL
PREPARED UNDER: SACRAMENTO AREA FLOOD CONTROL
AGENCY, CONTRACT NO. 1588
(Back of title page)

CERTIFICATION
This Engineer’s Report was prepared by the Sacramento Area Flood Control Agency (SAFCA) certification team including Psomas, Kleinfelder, Mead and Hunt, AECOM, and MBK Engineers (MBK). The purpose of this report is to support a finding that the American River North Levee System, which was constructed by USACE and is owned by the Central Valley Flood Protection Board (CVFPB) and operated and maintained by the American River Flood Control District (ARFCD), provides an urban level of flood protection (ULOP) in accordance and consistent with the requirements, definitions, and descriptions provided by:

State of California Department of Water Resources (DWR) ULOP Criteria (November 2013), Section 2, EVD-1.

State of California DWR Urban Levee Design Criteria (ULDC) (May 2012), Section 7.0.

The supporting documentation, calculations, data, definitions, limitations, and/or other pertinent information contained or referenced in this report form the basis of this certification. This certification does not constitute a warranty or guarantee of performance, express or implied. The certification is made for the American River North Levee System. Individual certification statements are provided in Appendix A for each ULDC topic, which have been endorsed by the certification team member responsible.

Water Resources Flood Control Water Rights
WALTER BOUREZ, III, P.E. FOUNDERS:

DON TRIEU, P.E.

DARREN CORDOVA, P.E. ANGUS NORMAN MURRAY
NATHAN HERSHEY, P.E., P.L.S. 1913-1985
LEE G. BERGFELD, P.E. JOSEPH I. BURNS
BEN TUSTISON, P.E. 1926-2021
THOMAS ENGLER, P.E., CFM DONALD E. KIENLEN
MICHAEL MONCRIEF, P.E. 1930-2023

NICOLE ORTEGA-JEWELL, PMP
KYLE KNUTSON, P.E.

ANNE WILLIAMS, P.E.

CERTIFICATION
This certification is provided to the Sacramento Area Flood Control Agency (SAFCA) for the sole purpose of supporting an Urban Level of Flood Protection (ULOP) finding. This certification is made in accordance with the requirements, definitions, and descriptions in the State of California Department of Water Resources’ (DWR) Urban Level of Flood Protection Criteria (November 2013), Section 2, Subsection EVD1 and Urban Levee Design Criteria (ULDC) (May 2012), Section 7.0 Urban Levee Design Criteria.

All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained or referenced in this document form the basis of this certification. This certification does not constitute a warranty or guarantee of performance, express or implied. This certification is made with respect to the American River North Levee System (Levee System), as described in the Urban Level of Flood Protection Engineer’s Report, October 2024 (Engineer’s Report).

Limits and Conditions of This Certification
This certification shall expire or become invalid at the earliest time any of the following conditions are met for any portion of the levee system:
 Integrity of the levee system has degraded to the point that the identified improvements will not be adequate to provide an urban level of flood protection, as determined by me, or a duly qualified designated successor.  Discovery of any substantive defect in the condition of any component of the levee system that was not known at the time this certification was made, and which materially affects the system’s ability to provide protection relative to a 1-in-200 chance of annual flood, as determined by me, or a duly qualified designated successor.
 20-years from the date of certification
Certification Statement
At the request of SAFCA, as supported by the information contained and referenced within the Engineer’s Report, this is to certify the following:
 Certification of Data and Information – The data and information presented in this report are accurate to the best of my knowledge.
 Certification of Analysis – To the best of my knowledge, the analyses conducted were performed in accordance with DWR’s ULDC and/or sound engineering practices, in a manner consistent with the degree of skill and care ordinarily exercised by members of the civil engineering profession currently practicing in the same locality under similar conditions.

I, Thomas F. Engler, PE, a professional registered civil engineer in the State of California, certify that the aforementioned levee system, as described in this Urban Level of Flood Protection Engineer’s Report, October 2024, provides an urban level of flood protection.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
__________________________________________________10/01/2024_______ Signature Date Not Valid Unless Stamped
i

TABLE OF CONTENTS
Table of Contents ......................................................................................... i List of Figures .................................................................................................................................... iii List of Appendices ........................................................................................................................... iii Acronyms and Abbreviations ...................................................................................................... iv

1.0 Introduction ........................................................................................ 1

2.0 Description of American River North Levee System ....................... 3

3.0 Physical Description ........................................................................... 3 Arcade Creek South Levee .................................................................................................................. 3 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River ..... 4 American River North Levee ............................................................................................................... 4

4.0 Performance History .......................................................................... 5

5.0 Evaluation of American River North Levee System ........................ 6 ULDC 7.1: Design Water Surface Elevation ............................................................................ 7 ULDC 7.2: Minimum Top of Levee ............................................................................................. 8 ULDC 7.3: Soil Sampling, Testing, and Logging ................................................................... 8 Arcade Creek South Levee .................................................................................................................. 9 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River ..... 9 American River North Levee ............................................................................................................... 9 ULDC 7.4: Slope Stability For Intermittently Loaded Levees .......................................... 10 Arcade Creek South Levee ............................................................................................................... 10 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 11 American River North Levee ............................................................................................................ 11 ULDC 7.5: Underseepage For Intermittently Loaded Levees ......................................... 12 Arcade Creek South Levee ............................................................................................................... 12 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 12 American River North Levee ............................................................................................................ 13 ULDC 7.6: Frequently Loaded Levees ..................................................................................... 13 ULDC 7.7: Seismic Vulnerability ................................................................................................ 13 ULDC 7.8: Levee Geometry......................................................................................................... 14 Arcade Creek South Levee ............................................................................................................... 14 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 15 American River North Levee ............................................................................................................ 15 ULDC 7.9: Interfaces and Transitions ...................................................................................... 15 Arcade Creek South Levee ............................................................................................................... 16 ii
Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 17 American River North Levee ............................................................................................................ 18 ULDC 7.10: Erosion ........................................................................................................................ 19 Arcade Creek South Levee ............................................................................................................... 19 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 20 American River North Levee ............................................................................................................ 20 ULDC 7.11: Right-of-Way ........................................................................................................... 21 Arcade Creek South Levee ............................................................................................................... 21 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 22 American River North Levee ............................................................................................................ 22 ULDC 7.12: Encroachments ........................................................................................................ 22 ULDC 7.13: Penetrations ............................................................................................................. 23 ULDC 7.14: Floodwalls, Retaining Walls, and Closure Structures ................................. 23 Arcade Creek South Levee ............................................................................................................... 24 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 25 American River North Levee ............................................................................................................ 25 ULDC 7.15: Animal Burrows ....................................................................................................... 26 ULDC 7.16: Levee Vegetation .................................................................................................... 26 ULDC 7.17: Wind Setup and Wave Runup ............................................................................ 26 Arcade Creek South Levee ............................................................................................................... 27 Natomas East Main Drainage Canal East Levee – Arcade Creek to American River .. 27 American River North Levee ............................................................................................................ 27 ULDC 7.18: Security ....................................................................................................................... 27 ULDC 7.19: Sea Level Rise ........................................................................................................... 28 ULDC 7.20: Emergency Actions and Flood Safety Plans .................................................. 28 ULDC 8.0 Operations & Maintenance .................................................................................... 29

6.0 Bibliography ..................................................................................... 29

iii

LIST OF FIGURES
Figure 1. American River North Levee System Levee Stationing and Features

LIST OF APPENDICES
Appendix A. Consultant Certification Statements
Appendix B. Independent Panel of Experts Report and Comment Closeout Appendix C. ULDC Water Surface Elevation Profiles – MBK Appendix D. American River North ULDC Due Diligence, Geotech – AECOM Appendix E. American River North ULDC Due Diligence, Geotech – Kleinfelder Appendix F. American River North ULDC Due Diligence, Geotech – MBK Appendix G. ULDC and FEMA Levee Inspection – MBK
Appendix H. O&M Right of Way Maps – Psomas
Appendix I. American River North ULDC Due Diligence, Civil – Mead & Hunt Appendix J. ULDC Required Plans
Appendix J1. Post Earthquake Remediation Plan – Kleinfelder Appendix J2. Right of Way Plan – MBK
Appendix J3. Penetration Exception Work Plan – Mead & Hunt Appendix J4. Rodent Control & Abatement Program – American River Flood Control District Appendix J5. Security Plan, American River North Levee System – American River Flood Control District
Appendix J6. Flood Safety Plan – American River Flood Control District Appendix J7. Encroachment Remediation Plan - MBK
iv

ACRONYMS AND ABBREVIATIONS

ACSL Arcade Creek South Levee
AEP annual exceedance probability
ALERT Automated Local Evaluation in Real Time
APF Adequate Progress Finding
ARCF American River Common Features
ARFCD American River Flood Control District
ARNL American River North Levee
cfs cubic feet per second
CPT Cone Penetration Test
CVFPB Central Valley Flood Protection Board
DWR California Department of Water Resources
DWSE Design Water Surface Elevation
EC Engineering Circular
EM Engineering Manual
ETL Engineering Technical Letter
FEMA Federal Emergency Management Agency
H:V horizontal-to-vertical ratio
HTOL Hydraulic Top of Levee
MBK MBK Engineers
MTOL Minimum Top of Levee
NEMDC Natomas East Main Drainage Canal
NEMDCEL Natomas East Main Drainage Canal East Levee
n.d. Not Dated
O&M operation and maintenance
pcf pounds per cubic foot
RM River Mile
SAFCA Sacramento Area Flood Control Agency
SB Senate Bill
SOP Standard Operating Procedure
SPFC State Plan of Flood Control
SPK Sacramento District (USACE)
ULDC Urban Levee Design Criteria
ULOP Urban Level of Flood Protection
UPRR Union Pacific Railroad
USACE U.S. Army Corps of Engineers
USGS United States Geologic Survey
WSE water surface elevation
v

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AMERICAN RIVER NORTH LEVEE SYSTEM
1 1.0 INTRODUCTION
In 2008, the California Legislature passed the Central Valley Flood Protection Act (Senate Bill (SB) 5), which requires all cities and counties within the Sacramento-San Joaquin Valley to make findings related to an urban level of flood protection for urban and urbanizing lands within a flood hazard zone. The bill defined “urban level of flood protection” as the level of flood protection necessary to withstand flooding that has a 1-in-200 chance of occurring in any given year (annual exceedance probability or AEP) using criteria consistent with, or developed by, the California Department of Water Resources (DWR). The Urban Level of Flood Protection Criteria (ULOP Criteria) implementation guidance, issued by the State in November 2013, requires that these findings be based on substantial evidence in the record.

This document and its associated appendices provide substantial evidence that the levee system protecting a portion of the urban area in Sacramento County protected by the American River North Levee, Natomas East Main Drainage Canal East Levee, and Arcade Creek South Levee meets ULOP Criteria for a 1-in-200 AEP in accordance with the State of California’s Urban Levee Design Criteria (ULDC), issued in May 2012.

ULOP Criteria (EVD-1) requires that the substantial evidence include, at a minimum, “a report prepared by a Professional Civil Engineer registered in California to document the data and analyses for demonstrating the property, development project, or subdivision has an urban level of flood protection.” The ULOP Criteria indicates that the Engineer’s Report should include the following:
 A list of the flood management facilities, including, but not limited to, State Plan of Flood Control (SPFC) facilities;
 The location of the flood management facilities;
 The entities that operate and maintain the flood management facilities; and  A list of, and consideration of, reports, evaluations, inspections, and performance history of the flood management facilities.

This Engineer’s Report relies on other documents, reports, analyses, and evaluations, some of which are listed in the bibliography at the end of this report. This report does not, nor is it intended to, present all the evidence in the record. Instead, this Engineer’s Report and its bibliography are limited to presenting the substantial evidence required to demonstrate that an urban level of flood protection exists.

Documents that evaluate and describe the condition and performance of the facilities that are not included in the bibliography are incorporated by reference. If the evaluation does not explicitly meet the criteria, an exception has been written and is included in the supporting documentation provided in the Due Diligence Reports included in the Appendices.

The ULOP Criteria also requires a report by an Independent Panel of Experts (IPE Panel) on the review of this Engineer’s Report. The Panel’s report and responses to the Panel’s comments are provided separately in Appendix B.

In October 2023, the City of Sacramento (City) adopted an Adequate Progress Finding (APF) for the six levee systems protecting the Sacramento metropolitan area within their jurisdictions. This included the American North Levee System. The APF was based on a report prepared by SAFCA titled, 2023 Urban Level of Flood Protection Annual Report, dated August 2023. Additionally, a report prepared by SAFCA URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
2 titled, Adequate Progress Towards an Urban Level of Flood Protection, Engineer’s Report, dated June 2016 provided recommendations related to the need for future improvements. This report presented substantial evidence that once the planned improvements identified in the report were completed, the structural flood control facilities protecting the urban areas of the City from flooding would be able to withstand flooding from a 1-in-200 AEP flood event, in accordance with the State of California’s ULDC, issued in May 2012.

Since improvements identified in the APF have been completed along the American River North Levee System, this Engineer’s Report certifies the American River North Levee System as meeting ULDC and the 1-in-200 AEP urban level of flood protection. This Engineer’s Report presents the substantial evidence needed to support this certification.

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AMERICAN RIVER NORTH LEVEE SYSTEM
3 2.0 DESCRIPTION OF AMERICAN RIVER NORTH LEVEE
SYSTEM
The American River North Levee System is comprised of 3 levees: the Arcade Creek south (left) levee/floodwall; Natomas East Main Drainage Canal (NEMDC) east (left) levee from Arcade Creek to the American River; and the American River north (right bank) levee from NEMDC to Arden Way (upstream end) (Figure 1). Left and right designations are locations of the levees based on looking downstream. The total levee length is approximately 14 miles. A detailed description of each levee is included under the Physical Description below.

3.0 PHYSICAL DESCRIPTION
In general, future waterside development is not allowed and landside development within 50 feet of the levee is limited per a local grading ordinance which also restricts construction of swimming pools. In 2013, the City of Sacramento adopted a grading ordinance (Ordinance 2013-0020 Section 1; Ordinance 2013- 0007 Section 1) outlined in Title 17, Division II, Article III (17.200.340 F zone - Setbacks) that restricts any grading activity within 50 feet of the levee. Sacramento County has adopted a similar ordinance found in Sacramento County Zoning Code Section 4.7.3 Development Standards, specifically for Lots Protected by Levees (Section 4.7.3.A) which restricts construction of structures to no closer than 25 feet from the landside levee toe. Where swimming pools are located in close proximity to the landside levee toe, the geotechnical engineering review has assessed the condition, and a discussion is provided in the supporting documentation included in Appendices D, E, and/or F.

ARCADE CREEK SOUTH LEVEE
The Arcade Creek south levee was originally constructed by local groups in the early 1930s and extends from the NEMDC (Station 4000+00) upstream approximately 2 miles to Marysville Boulevard (Station 4110+00).

The downstream portion (Station 4000+00 to 4068+00) was improved by the U.S. Army Corps of Engineers (USACE) in the 1950s and included construction of waterside fill consisting of less permeable material. In the 1990s, SAFCA raised the upstream levee crest and constructed a continuous floodwall along the waterside edge of the crest between Rio Linda Boulevard (Station 4068+00, approximately) and Marysville Boulevard (Station 4110+00). Floodwall heights range between 0.5 and 3.5 feet above the levee embankment crest with wall heights increasing upstream and tying into high ground at Marysville Boulevard.

The levee is crossed by three bridges at Norwood Avenue, Rio Linda Boulevard, and the Sacramento Northern Bike Trail. The UPRR railroad, adjacent to the NEMDC east levee, crosses the Arcade Creek south levee at the connection of the two levees. There is no waterside development. Landward of the levee, suburban development is present adjacent to the levee toe. The Rio Linda Boulevard Bridge was raised after the 1986 flood event, and SAFCA tied the levee into the bridge railings in 1996; the Norwood Avenue bridge was subsequently raised also. No closure structures are currently present at these crossings as they are elevated above the levee. In 2019 a seepage cutoff wall was constructed along this stretch of levee.

Construction included modifications to pump stations and select penetrations to bring them in compliance with ULDC and other requirements. In 2024, a segment of the waterside slope immediately downstream of Rio Linda Boulevard was replaced with low permeable fill to address a gap in the waterside fill.

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AMERICAN RIVER NORTH LEVEE SYSTEM
4 NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC east levee was originally constructed by local groups in the early 1930s and was improved in the 1950s by the USACE. The NEMDC east levee, within the American River North Levee System, extends from Arcade Creek south levee to the American River north levee.

The NEMDC east levee from Arcade Creek south levee to the American River north levee (Station 2986+50 to 3051+40) is approximately 1.2 miles long. In the 1990s, SAFCA raised the levee and reconstructed the waterside and landside slopes from approximately Station 3001+50 to 3051+640 Additional structures are located at the Arden Garden Bridge near Station 3003+50 and the West El Camino Bridge (Station 3021+75) that includes floodwalls on the upstream and downstream sides of the bridge.

The railroad and the levee meet at approximately Station 3001+50 and continues to 3051+40 where the levee turns east and the railroad continues north. The railroad embankment runs along the landside of the levee and is about 6 feet lower than the levee crest. A discontinuous ditch, lined and unlined depending on location, is located approximately 10 to 45 feet from the landside railroad embankment toe (50 to 90 feet from the projected levee prism toe) from Station 3002+50 to 3051+40. There is no waterside development. Landward of the levee, land use is suburban development with a few undeveloped parcels and commercial properties.

No past performance issues (besides inadequate freeboard above the design flood level) have been reported along this reach.

AMERICAN RIVER NORTH LEVEE
The American River north levee was originally constructed by local groups in the late 1800s and early 1900s and was subsequently improved by USACE in the mid-1900s as part of the Sacramento River Flood Control Project and the American River Levee Project. Beginning in 1998 and extending through the early 2000s, USACE installed significant lengths of cutoff wall in the levee as part of the American River Watershed Common Features Project. Most of the levee was constructed prior to construction of the Folsom Dam and, is therefore, generally setback from the channel. The federally authorized American River north levee extends from the NEMDC (Station 3000+00) upstream to approximately Claremont Rd, upstream of Arden Way (Station 3582+00). However, the portion of levee upstream of Arden Way, i.e., between Station 3548+50 and 3582+00 was deauthorized by the Water Resources Development Act of 2022. The levee being evaluated is approximately 10.4 miles. Cutoff walls are present for almost the entire length of levee upstream of Cal Expo. While the original cutoff wall that was constructed left gaps at road crossings and utilities, those gaps have been subsequently improved to pass the Common Features design flow of 160,000 cfs.

The levee is crossed by several transportation routes: Del Paso Boulevard, Highway 160, Capital City Freeway (Interstate 80 Business Route), UPRR, Southern Pacific Railroad, H Street, Guy West Bridge (pedestrian walkway), Howe Avenue, Watt Avenue, Harrington Way, and River Walk Way. Several residential streets terminate at the landside of the levee. A Sacramento County Sheriff’s training facility and former sewage treatment plant are located on the waterside of the levee near River Walk Way. Land use on the landside of the levee consists predominantly of commercial and industrial development up to Cal Expo Fairgrounds. Upstream of Cal Expo, landside use is predominately suburban development and URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
5 occasional commercial development. Recreation land uses (i.e. parks and bike trails) are present along the waterside of the levee.

Following the historic 1986 flood, and under the direction of Congress, the USACE undertook a general investigation for reducing flood risk to the City of Sacramento. In 1996, the USACE ultimately recommended several incrementally justified elements that were common to the different plans the investigation developed. These “common features” included remediation of 24 miles of the American River north and south levees. The proposed remediation for the American River levees was subsequently expanded to include some levee raising, erosion protection, and additional seepage remediation. All of the remediation authorized in 1996, and subsequently augmented in 1999, has been constructed by the USACE.

The design of features along the American River, constructed by the USACE as part of the USACE Common Features Project, were completed prior to the development of the ULDC and the requirements for an ULOP which did not exist at the time. Specifically, upon completion of the “common features” as part of the general reevaluation, the American River levee is able to pass a flow of 160,000 cfs, which is greater than the flow of 115,000 cfs that is being used for the ULDC certification. The USACE Sacramento District, Engineering Division Chief has determined (USACE, no date) that the American River levees meet USACE minimum top of levee (MTOL) freeboard, slope stability, and seepage criteria for a Folsom Dam release of 115,000 cfs. Because USACE has provided this letter, and the Design Water Surface Elevation (DWSE) for the project exceeds the DWSE required for ULDC, the evaluation in this Engineer’s Report relies on the USACE letter for its conclusions related to MTOL, stability, and seepage for the American River north levee.

4.0 PERFORMANCE HISTORY
No past performance issues related to seepage or stability distress have been reported along these reaches due to high water events including events from 1986 and 1997. Long term past performance issues including erosion, which is now largely mitigated through waterside bank protection placed over time, and potential future through seepage, underseepage, and slope instability is now largely mitigated through installation of cutoff walls. There was no reported distress between 1997 to 2023.

ARCADE CREEK SOUTH LEVEE
The performance history assessment for the Arcade Creek south levee is based on review of available records and information at the United States Geologic Survey (USGS) Arcade Creek near Del Paso Heights gage (11447360) and the co-located Sacramento County Automated Local Evaluation in Real Time (ALERT) Arcade Creek at Watt Avenue gage (47336). The ALERT gage uses USGS gage height data, converted to NAVD88 by adding 49.19 feet. The gage is located just upstream of Watt Avenue and about

5.5 miles upstream of the start of the Arcade Creek south levee. The ALERT gage has a defined “monitor stage” of 62.4 feet and a “flood stage” of 63.4 feet.

Annual peak stage data is available for the USGS gage for 43 water years, starting in 1964. The monitor stage has been equaled or exceeded in 18 years, and the flood stage was equaled or exceeded in 9 years.

All of these have been below the 200-year DWSE.

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AMERICAN RIVER NORTH LEVEE SYSTEM
6 NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE
There are no gages in the NEMDC east levee reach with defined monitor or flood stages. The Arcade Creek performance history assessment is informative for the NEMDC east levee reach since Arcade Creek feeds the NEMDC upstream of the east levee reach. The nearest gage on the NEMDC upstream of the east levee reach with defined monitor and flood stages is the Sacramento County ALERT gage on the downstream side of the D-15 pump station (47344), located a little over 3 miles upstream of the ARN NEMDC east levee reach. The monitor stage for the D-15 downstream gage is 31.3 feet, and the flood stage is 40.5 feet. Gage data is available for water years 2015 through 2024. In that period, the flood stage has never equaled or exceeded, with a maximum recorded stage of 37.05, on 1/11/2017. In the 10 years of record, there have been 34 occurrences of the monitor stage being equaled or exceeded. All of these have been below the 200-year DWSE.

AMERICAN RIVER NORTH LEVEE
The performance history assessment for the American River north levee is based on review of available records and information at the USGS American River at Fair Oaks gage (11446500) and CA DWR American River at H Street gage (A0714). The H Street gage has a defined “monitor stage” of 39.0 feet, “flood stage” of 42.0 feet, and “danger stage” of 43.0 feet. The H Street gage record is readily available only back to 1983, whereas the Fair Oaks gage record goes back to 1905. A relationship was developed between the flow at Fair Oaks and the gage height at H Street (see Figure 1) so an estimate could be made of how often the monitor, flood and danger stages have been equaled or exceeded since the completion of Folsom Dam in 1955. These occurrences are summarized in Table 1. All of these have been below the 200-year DWSE.

Table 1. Estimated Frequency of H Street Gage Height Exceeding Monitor, Flood and Danger Stages Stage
H Street
Gage Height
(feet)
Estimated
Corresponding Fair
Oaks flow (cfs)
Number of years equaled or
exceeded since completion
of Folsom Dam
(67-year period of record)
Monitor 39 88,000 5
Flood 42 120,000 1
Danger 43 140,000 0

5.0 EVALUATION OF AMERICAN RIVER NORTH LEVEE
SYSTEM
The ULDC requires analysis under the 20 categories listed below. SAFCA’s certification team evaluated the American River North Levee System for compliance with each of the 20 ULDC categories. The evaluations are summarized in the following report subsections, and detailed documentation of the analyses are provided as appendices to this report.

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AMERICAN RIVER NORTH LEVEE SYSTEM
7 7.1 Design Water Surface Elevation

7.2 Minimum Top of Levee

7.3 Soil Sampling, Testing, and Logging

7.4 Slope Stability for Intermittently Loaded Levees

7.5 Underseepage for Intermittently Loaded Levees

7.6 Frequently Loaded Levees

7.7 Seismic Vulnerability

7.8 Levee Geometry

7.9 Interfaces and Transitions

7.10 Erosion

7.11 Right-of-Way

7.12 Encroachments (Excluding Penetrations, Closure
Structures, and Levee Vegetation)

7.13 Penetrations

7.14 Floodwalls, Retaining Walls, and Closure Structures

7.15 Animal Burrows

7.16 Levee Vegetation

7.17 Wind Setup and Wave Runup

7.18 Security

7.19 Sea Level Rise

7.20 Emergency Actions and Flood Safety Plans
ULDC 7.1: DESIGN WATER SURFACE ELEVATION
The ULDC DWSE is the 1-in-200 AEP water surface elevation (WSE) used to design and evaluate levees and floodwalls for the purposes of providing an urban level of flood protection.

The ULDC offers two options for determination of the DWSE: 1) the Federal Emergency Management Agency (FEMA) approach, and 2) the USACE approach. The evaluation for the American River North Levee System conforms to the FEMA approach. In accordance with the ULDC, debris loading on bridge piers was included in the hydraulic analysis. The ULDC also requires adjustments for sea level rise and superelevation. Sea level rise was incorporated into the modeling downstream boundary conditions and there are three locations along the American River North Levee System subject to superelevation – URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
8 American River (RM 3.6 and 5.7) and NEMDC (RM 2.6). Climate change is considered optional in the ULDC and was not adjusted for in this modeling. Hydrology and hydraulics modeling were updated in the model based on a new model provided by the Central Valley Hydrology Study (CVHS, 2015). A detailed description of the determination of the DWSE is found in Technical Memorandum, American River North Levee System - Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee (MBK, 2024a).

An additional elevation required by the ULDC is the hydraulic top of levee (HTOL), which is defined as the lower of the DWSE plus 3 feet or the median 500-year WSE.

The computed DWSEs for the American River North Levee System are described in (MBK, 2024a) and provided in Appendix C
The American River North Levee System meets ULDC 7.1 for development of the DWSE.

ULDC 7.2: MINIMUM TOP OF LEVEE
The Minimum Top of Levee (MTOL) is the required minimum elevation for the physical top of levee to provide a reasonable assurance of containing the DWSE and is defined as the higher of the DWSE plus 3 feet or the DWSE plus wind setup and wave runup. The determination of the MTOL is described in (MBK, 2024a) and provided in Appendix C.

Wind setup and wave runup were computed by Mead & Hunt (Mead & Hunt, 2024b), and are discussed below in ULDC 7.17. There are no locations along the American River North Levee System where the combined wind setup and wave runup is greater than 3 feet; therefore, the MTOL is the DWSE plus 3 feet.

Figures 11, 12, and 13 in Technical Memorandum, American River North Levee System - Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee (MBK, 2024a) provides a profile showing the computed MTOL and actual top of levee profile.

The American River North Levee System meets ULDC 7.2 for MTOL.

ULDC 7.3: SOIL SAMPLING, TESTING, AND LOGGING
ULDC 7.3 requires soil sampling, testing, and logging, as per standard procedures prescribed in guidance documents, including the USACE Sacramento District (SPK) Standard Operating Procedure 3 Geotechnical Levee Practice (SOP-3) and DWR Division of Flood Management’s Soil and Rock Logging, Classification, Description and Presentation Manual (DWR, 2009). This includes an evaluation of soil exploration quantity and location as outlined in the SPK SOP-3. Based on this document, explorations for levee evaluation should be obtained at the waterside toe, levee crest, landside toe, and landside field areas performed at a spacing of 1,000 to 2,000 feet for feasibility studies, and at a spacing of 500 to 1,000 feet for design and preconstruction engineering studies. The SPK SOP-3 also recommends a thorough evaluation of existing information, as available, including construction documents, improvements, performance history, existing subsurface information, and regional and local geomorphology. The standard also recommends the use of cone penetrometers (CPTs) and geophysics to supplement borings, where appropriate.

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9 ARCADE CREEK SOUTH LEVEE
The Arcade Creek South Levee was evaluated by AECOM. The required quantity and spacing of explorations, following USACE protocols was not met and an exception is needed for this ULDC topic. The justification for this exception is described in the due diligence report prepared by AECOM which is provided in Appendix D. AECOM reviewed the explorations performed along this levee segment, along with as-builts, construction documentation, surficial geologic mapping and geomorphic assessments, resistivity surveys, and previous engineering documents. The recent construction activity included construction of a cutoff wall that involved full time trench logging and waterside slope reconstruction. As such, this review and compilation of data indicates that sufficient documentation exists to meet this ULDC requirement through exception.

Therefore, the Arcade Creek South Levee meets the requirements for ULDC 7.3 Soil Sampling, Testing and Logging, by exception.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC East Levee was evaluated by MBK Engineers (NEMDCEL Station 2986+50 to 3001+50), Kleinfelder (NEMDCEL Station 3001+50 to 3029+00), and AECOM (NEMDCEL Station 3029+00 to 3051+00). For all of these segments, the required quantity and spacing of explorations following USACE protocols was not met, and an exception is needed for this ULDC topic. The justification for this exception is described in each of the due diligence reports prepared by AECOM, Kleinfelder, and MBK Engineers which are provided as Appendices D, E, and F, respectively. In general, additional field observations, mapping, and documentation to understand the construction interaction with the subsurface stratigraphy was performed along the NEMDC east levee. This additional documentation, along with asbuilt plans and construction records are considered sufficient documentation to meet this requirement through exception. Construction records include full time trench logging by a USACE representative for the USACE contracted slurry cutoff and jet grout walls; contractor explorations needed for mix design prior to construction along each of the cutoff wall and jet grout reaches; prior geotechnical explorations performed by USACE and other consultants; geomorphology and geologic map interpretations; as-built documentation for the original levees and improvements, and QC/QA laboratory testing results.

Therefore, the NEMDC East Levee meets the requirements for ULDC 7.3 Soil Sampling, Testing, and Logging by exception.

AMERICAN RIVER NORTH LEVEE
The American River North Levee was evaluated by Kleinfelder (ARNL Station 3000+00 to 3051+00) and MBK Engineers (ARNL Station 3051+00 to 3548+50). For these segments, the required quantity and spacing of explorations following USACE protocols was not met, and an exception is needed for this ULDC topic. The justification for this exception is described in the due diligence reports prepared by Kleinfelder (Appendix E), and MBK Engineers (Appendix F). The evaluation of explorations was not exhaustive, as a majority of this levee segment was remediated over the last 25 years through construction of seepage cutoff walls. It is known that waterside and landside explorations at a distance from the levee toe were generally not performed and, therefore, an exception is needed for this ULDC URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
10 topic. The justification for this exception of a lack offset explorations is the availability of additional field observations, mapping, and documentation to understand the construction interaction with the subsurface stratigraphy. These cutoff walls required additional contractor led explorations and full-time trench logging of the excavation. Documentation includes full time trench logging by a USACE representative for the USACE contracted slurry cutoff and jet grout walls; contractor explorations needed for mix design prior to construction along each of the cutoff wall and jet grout reaches; prior geotechnical explorations performed by USACE and other consultants; geomorphology and geologic map interpretations; as-built documentation for the original levees and improvements and QC/QA laboratory testing results. As such, this review indicates that sufficient documentation exists to meet this ULDC requirement through exception.

Therefore, the American River North Levee meets the requirements for ULDC 7.3 Soil Sampling, Testing, and Logging, by exception.

ULDC 7.4: SLOPE STABILITY FOR INTERMITTENTLY LOADED
LEVEES
ULDC 7.4.1 requires a minimum factor of safety of 1.4 for landside slope stability under steady state seepage conditions for intermittently loaded levees, based on the DWSE, for failure surfaces that intersect the levee crest and are greater than a few feet deep in the levee slope. It also requires a minimum factor of safety of 1.2, based on the Hydraulic Top of Levee (HTOL)1, for failure surfaces that intersect the levee crest and are greater than a few feet deep in the levee slope. ULDC 7.4.2 requires a minimum factor of safety of 1.0 to 1.2 for waterside slope stability during rapid drawdown conditions for the DWSE, depending on how long the embankment is saturated, with the higher factor of safety used for events of a longer duration. An intermittently loaded levee is defined as “a levee that does not experience a water surface elevation of one foot or higher above the elevation of the levee toe at least once a day for more than 36 days per year on average.”

ARCADE CREEK SOUTH LEVEE
AECOM has reviewed the current slope stability analyses and found them to meet slope stability criteria using the 200-year DWSE and HTOL water levels. Levee crest profiles and levee cross sections used previously for slope stability analysis are consistent with recent surveys (Psomas 2024 and reevaluation at critical sections is not necessary. AECOM also compared the DWSE used in prior analysis with the current 200-year DWSE and determined that the WSE was equal to or lower than values used in prior evaluations.

In addition, based on a review of available construction records, geotechnical data, construction materials, construction quality control and quality assurance testing, historic performance, and the slope stability analysis referenced in the due diligence report prepared by AECOM (Appendix D) meet slope stability criteria.

Therefore, the Arcade Creek South Levee meets the requirements for ULDC 7.4 Slope Stability for Intermittently Loaded Levees.
1 The hydraulic top of levee is defined by ULDC as the lower of the median 200-year WSE plus 3 feet or the median 500-year WSE. The HTOL was developed using the approach described in ULDC 7.1 URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
11 NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC East Levee was evaluated by MBK Engineers (NEMDCEL Station 2986+50 to 3001+50), Kleinfelder (NEMDCEL Station 3001+50 to 3029+00), and AECOM (NEMDCEL Station 3029+00 to 3051+00). For these segments, prior engineering analyses performed by AECOM and Kleinfelder were reviewed to confirm the existing and/or remediated levee configurations meet ULDC and USACE minimum factor of safety requirements for slope stability. These analyses were reviewed to compare the prior evaluated WSE to the revised 200-year WSE prepared for this evaluation (Appendix C). A summary of slope stability analyses is described in the due diligence reports prepared by AECOM (Appendix D) and Kleinfelder (Appendix E). Kleinfelder and AECOM concluded the analysis was performed at critical sections and met criteria. The evaluated WSE was higher than the new 200-year WSE, and the modeled improvements were the same or less conservative than the constructed features. These results provide the condition evaluated, water surface designation, and the calculated slope stability factor of safety. MBK summarized the analysis results performed by others supporting the Statement of Performance provided by USACE and the adequacy of the completed construction projects for the levee segment described herein. A summary of MBK’s evaluation of prior slope stability analyses is included in the Due Diligence Report provided by MBK in Appendix F.

Therefore, the NEMDC East Levee meets the requirements for ULDC 7.4 Slope Stability for Intermittently Loaded Levees.

AMERICAN RIVER NORTH LEVEE
The American River North Levee was evaluated by Kleinfelder (ARNL Station 3000+00 to 3051+00) and MBK Engineers (ARNL Station 3051+00 to 3548+50). For these segments, prior engineering analyses performed by Kleinfelder were reviewed to confirm the existing and/or remediated levee configurations meet ULDC and USACE minimum factors of safety for slope stability. These analyses were reviewed to compare the prior evaluated WSE to the revised 200-year WSE prepared for this evaluation (Appendix C).

A summary of prior slope stability analyses is described in the due diligence report prepared by Kleinfelder (Appendix E). Kleinfelder concluded the analysis was performed at critical sections and met analysis criteria. The evaluated WSE was higher than the new 200-year WSE, and the modeled improvements were the same or less conservative than the constructed features. These results provide the condition evaluated, water surface designation, and the calculated factors of safety. MBK summarized the analysis results performed by others supporting the Statement of Performance provided by USACE and the adequacy of the completed construction projects for the levee segment described herein. A summary of MBK’s slope stability evaluation is included in the Due Diligence Report provided by MBK in Appendix F.

Therefore, the American River North Levee meets the requirements for ULDC 7.4 Slope Stability for Intermittently Loaded Levees.

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AMERICAN RIVER NORTH LEVEE SYSTEM
12 ULDC 7.5: UNDERSEEPAGE FOR INTERMITTENTLY LOADED
LEVEES
This section describes the levee documentation and general requirements for ULDC 7.5, Underseepage for Intermittently Loaded Levees. An intermittently loaded levee is defined as “a levee that does not experience a water surface elevation of one foot or higher above the elevation of the levee toe at least once a day for more than 36 days per year on average.”
“Levee underseepage criteria for intermittently loaded levees are as follows:
• The underseepage exit gradient for levees is required to be 0.5 or less at the landside levee toe using a steady-state seepage analysis for a water surface set at the DWSE. For levees with a landside blanket layer with a saturated unit weight less than 112 pounds per cubic foot (pcf), a minimum factor of safety for underseepage of 1.6 is required at the landside levee toe. • The underseepage exit gradient is required to be 0.8 or less at the toe of a seepage berm less than 300 feet wide using steady-state seepage analysis for a water surface set at the DWSE. If the saturated unit weight of the blanket layer is less than 112 pcf, a minimum factor of safety for underseepage of 1.0 is required at the toe of the seepage berm.” • The underseepage exit gradient for levees is required to be 0.6 or less at the landside levee toe using a steady-state seepage analysis for a water surface set at the HTOL. For levees with a landside blanket layer with a saturated unit weight less than 112 pounds per cubic foot (pcf), a minimum factor of safety for underseepage of 1.3 is required at the landside levee toe.

ARCADE CREEK SOUTH LEVEE
AECOM has reviewed the current seepage evaluations and found it to meet seepage criteria using the 200-year DWSE and HTOL water levels. Levee crest profiles and levee cross sections used previously for seepage analyses are consistent with recent surveys (Psomas, 2024) and reevaluation of critical sections is not necessary. In addition, based on a review of available construction records, geotechnical data, construction materials, construction quality control and quality assurance testing, historic performance, and the post-construction seepage analyses referenced in the due diligence report prepared by AECOM (Appendix D) meet underseepage requirements.

Therefore, the Arcade Creek South Levee meets the requirements for ULDC 7.5 Underseepage for Intermittently Loaded Levees.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC East Levee was evaluated by MBK Engineers (NEMDCEL Station 2986+50 to 3001+50), Kleinfelder (NEMDCEL Station 3001+50 to 3029+00), and AECOM (NEMDCEL Station 3029+00 to 3051+00). For these segments, prior engineering analyses performed by AECOM and Kleinfelder were reviewed to confirm the existing and/or remediated levee configurations meet ULDC and USACE maximum seepage gradient criteria. These analyses were reviewed to compare the prior evaluated WSE to the revised 200-year WSE prepared for this evaluation (Appendix C). A summary of prior seepage analyses URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
13 is described in the due diligence reports prepared by AECOM (Appendix D) and Kleinfelder (Appendix E).

Kleinfelder concluded the analysis was performed at critical sections and met analysis criteria. The evaluated WSE was higher than the new 200-year WSE, and the modeled improvements were the same or less conservative than the constructed features. These results provide the condition evaluated, water surface designation, and the calculated seepage gradients. MBK summarized the analysis results performed by others supporting the Statement of Performance provided by USACE and the adequacy of the completed construction projects for the levee segment described herein. A summary of MBK’s seepage evaluation is included in the Due Diligence Report provided by MBK in Appendix F.

Therefore, the Natomas East Main Drainage Canal East Levee meets the requirements for ULDC 7.5 Underseepage for Intermittently Loaded Levees.

AMERICAN RIVER NORTH LEVEE
The American River North Levee was evaluated by Kleinfelder (ARNL Station 3000+00 to 3051+00) and MBK Engineers (ARNL Station 3051+00 to 3548+50). For these segments, prior engineering analyses performed by Kleinfelder were reviewed to confirm the existing and/or remediated levee configurations meet ULDC and USACE maximum seepage gradient criteria. These analyses were reviewed to compare the prior evaluated WSE to the revised 200-year WSE prepared for this evaluation (Appendix C). A summary of prior seepage analyses is described in the due diligence report prepared by Kleinfelder (Appendix E).

Kleinfelder concluded the analysis was performed at critical sections and met analysis criteria. The evaluated WSE was higher than the new 200-year WSE, and the modeled improvements were the same or less conservative than the constructed features. These results provide the condition evaluated, water surface designation, and the calculated seepage gradients. MBK summarized the analysis results performed by others supporting the Statement of Performance provided by USACE and the adequacy of the completed construction projects for the levee segment described herein. A summary of MBK’s seepage evaluation is included in the Due Diligence Report provided by MBK in Appendix F.

Therefore, the American River North Levee meets the requirements for ULDC 7.5, Underseepage for Intermittently Loaded Levees.

ULDC 7.6: FREQUENTLY LOADED LEVEES
ULDC 7.6 clarifies that frequently loaded levees are subject to more stringent requirements. Frequently loaded levees are those levees that experience a WSE of 1 foot or higher above the elevation of the landside levee toe at least once a day for more than 36 days per year on average.

As part of the Urban Levee Evaluation Program, DWR determined that the American River north levee, Arcade Creek south levee, and NEMDC east levee are intermittently loaded levees (URS, 2015b). The SAFCA certification team reviewed DWR’s conclusion and concurs. ULDC 7.6 for frequently loaded levees is not applicable.

ULDC 7.7: SEISMIC VULNERABILITY
ULDC 7.7 requires an analysis of seismic vulnerability of the levee system for the 200-year return period ground motions. ULDC 7.7.1 indicates that if seismic damage from the 200-year return period ground URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
14 motion is expected, a post-earthquake remediation plan is required as part of a flood safety plan developed in coordination with pertinent local, State, and Federal agencies.

A seismic vulnerability analysis was performed by Kleinfelder to evaluate liquefaction potential and pseudo static stability. This evaluation is summarized in the 2024 Kleinfelder Seismic Performance Summary Report included as an appendix to the Due Diligence report provided in Appendix E.

This evaluation determined that four segments along the American River north levee have liquefiable layers and/or seismic stability concerns which categorize these segments as High Seismic Vulnerability.

These segments are American River north levee Station 3016+00 to 3044+48, Station 3085+35 to 3088+60, Station 3167+50 to 3306+00, and Station 3458+85 to 3482+50. These findings are consistent with analyses that were performed previously in 2015 (URS, 2015). The Arcade Creek south levee and Natomas East Main Drainage Canal east levee were evaluated to have acceptable factors of safety against liquefaction and were classified to have low seismic vulnerability.

Due to these findings, a post-earthquake remediation plan is required for portions of the American River north levee. This plan has been prepared and is provided in Appendix J1.

Therefore, with inclusion of the Post Earthquake Remediation Plan, the Arcade Creek south levee, Natomas East Main Drainage Canal east levee, and American River north levee meet ULDC 7.7.

ULDC 7.8: LEVEE GEOMETRY
ULDC 7.8 requires that for new levees or levees with extensive reconstruction situated along major waterways, a minimum 20-foot-wide crown width for Major Streams (mainstreams) or 12-foot crown width for Minor Streams (tributaries to mainstream) and 3:1 horizontal-to-vertical ratio (H:V) waterside and landside slopes are required. Landside slopes can remain 2H:1V for existing levees with good performance. As outlined in the 1953 MOU, the American River North Levee is considered a major stream levee and the NEMDC east levee and Arcade Creek south levee are considered minor stream levees.

ULDC 7.8.1 allows levees wider than the minimum requirement to have steeper slopes if the minimum required dimensions would fit entirely within the actual levee, and if seepage and slope stability criteria are met (for both deep and shallow failure surfaces).

ULDC 7.8.2 requires a patrol road along the crest of the levee for inspection, maintenance, and floodfighting. The patrol road must be designed, constructed, and maintained to provide “all-weather” support of maintenance and patrolling vehicles.

ARCADE CREEK SOUTH LEVEE
The Arcade Creek south levee is classified as minor stream levee. The ULDC requires that minor stream levees have the following geometry (minimum theoretical prism):
• 2H:1V landside slope
• 12-foot-wide levee crown
• 3H:1V waterside slope
Construction projects have modified the original levee including geometry corrections. These corrections are consistent with ULDC requirements and as-builts of these projects and recent survey data verify these URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
15 criteria were met. Psomas obtained recent ground survey data (Psomas, 2024) to compare existing geometry to criteria. Cross sections are included in the Due Diligence Report prepared by AECOM, provided in Appendix D. These cross sections confirm the prior as-built cross sections still exist which indicate the Arcade Creek south levee meets current geometry criteria.

Therefore, the Arcade Creek south levee meets requirements for ULDC 7.8 Levee Geometry.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC east levee is classified as a minor stream levee. The ULDC requires that minor stream levees have the following geometry (minimum theoretical prism):
• 2H:1V landside slope
• 12-foot-wide levee crown
• 3H:1V waterside slope
Construction projects have modified the original levee including geometry corrections. These corrections are consistent with ULDC requirements and as-builts of these projects and recent survey data verify these criteria were met. Psomas obtained recent ground survey data (Psomas, 2024) to compare existing geometry to criteria. Cross sections are included in Appendices D, E, and F of the Due Diligence Reports prepared by AECOM, Kleinfelder, and MBK, respectively. These cross sections confirm the prior as-built cross sections still exist which indicate the NEMDC east levee meets current geometry criteria.

Therefore, the NEMDC east levee meets requirements for ULDC 7.8 Levee Geometry.

AMERICAN RIVER NORTH LEVEE
The American River north levee is classified as a major stream levee. The ULDC requires that major stream levees have the following geometry (minimum theoretical prism):
• 2H:1V landside slope
• 20-foot-wide levee crown
• 3H:1V waterside slope
Construction projects have modified the original levee including geometry corrections. These corrections are consistent with ULDC requirements and as-builts of these projects and recent survey data verify these criteria were met. Psomas obtained recent ground survey data (Psomas, 2024) to compare existing geometry to criteria. Cross sections are included in Appendices E and F of the Due Diligence Reports prepared by Kleinfelder and MBK, respectively. These cross sections confirm the prior as-built cross sections still exist which indicate the American River north levee meets current geometry criteria.

Therefore, the American River north levee meets requirements for ULDC 7.8 Levee Geometry.

ULDC 7.9: INTERFACES AND TRANSITIONS
This section describes the levee documentation and general requirements for ULDC 7.9 Interfaces and Transitions.

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AMERICAN RIVER NORTH LEVEE SYSTEM
16 “The civil engineer must consider, evaluate, and explicitly design for interfaces and transitions between different types of levee sections and features along a levee system. Appropriate overlaps, transitions, and connections between features must be evaluated and designed to ensure that the levee system functions holistically, such that no levee reach is more susceptible to problems than an adjacent reach due to gaps in features, loading/demand concentrations, or other three-dimensional effects. Such interfaces, transitions, and connections commonly occur at the ends of seepage berms, seepage cutoff walls, revetments, and floodwalls.”
ULDC 7.9 highlights the need to ensure that the levee system functions holistically, such that no levee reach is more susceptible to problems than an adjacent reach, due to gaps in features, loading/demand concentrations, or other three-dimensional effects when designing interfaces, transitions, and connections that commonly occur at the ends of seepage berms, seepage cutoff walls, and revetments.

Boundary conditions at each of the intersections of the levee segments were evaluated to consider the most critical loading scenario with respect to underseepage and stability. These evaluations were performed by AECOM, Kleinfelder, and MBK Engineers, with conclusions provided in Appendices D, E and F Due Diligence Reports.

A summary of the transitions and interfaces present in this levee system are outlined below.

ARCADE CREEK SOUTH LEVEE
A summary of the interface and transitions reviewed along the Arcade Creek south levee are provided below. Additional documentation can be found in the due diligence report prepared by AECOM provided in Appendix D.
1) ACSL Station 4001+85: Transition at end of seepage cutoff wall and transition of UPRR to ACSL embankment. A gap in remediation between the wall and UPRR was reviewed and determined to not require additional remediation. The City of Sacramento interior drainage pump station is also located at this area and was found to be outside the levee footprint and is not a concern.

However, a drainage relief trench was installed under the basin as a resiliency measure. This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) 2) ACSL Station 4013+00: Transition from levee centerline seepage cutoff wall to ACSL embankment.

The end station for the wall was selected to include an extension for potential end around affects.

This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024)
3) ACSL Station 4031+18: Transition from ACSL embankment to levee centerline seepage cutoff wall.

The beginning station for the wall was selected to include an extension for potential end around effects. This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024)
4) ACSL Station 4035+10: Transition from ACSL to Norwood Avenue bridge. An SCCB seepage cutoff wall was constructed across the road at this location. The adjacent seepage cutoff walls were constructed with a 25-foot overlap on either side. This structure was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
17 5) ACSL Station 4063+00: Transition from ACSL to Sacramento Northern Bike Trail bridge. An SCCB seepage cutoff wall was constructed across the bike trail at this location. The adjacent seepage cutoff walls were constructed with a 25-foot overlap on either side. This structure was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) 6) ACSL Station 4068+45: A gap in the wall was present at Rio Linda Boulevard. In order to close this gap, the upstream toe wall continued downstream under the bridge to provide an overlap of the downstream centerline wall that terminated on the west side of the Rio Linda Boulevard Bridge.

The overlap is approximately 180 feet. A two-dimensional seepage model was performed to evaluate and confirm this configuration met criteria. The transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) 7) ACSL Station 4083+21: Transition from seepage cutoff wall to ACSL embankment. The end stationing for the wall was selected to include extension for potential end around affects. This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024). 8) ACSL Station 4100+00: Arcade Creek south levee transitions to high ground at Marysville Boulevard. The ground surface is generally above the DWSE. This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) These overlaps and transitions are considered appropriate as discussed above for the NEMDC East Levee.

Therefore, the Arcade Creek south levee meets requirements for ULDC 7.9 Interfaces and Transitions.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
A summary of the interface and transitions reviewed along the NEMDC east levee are provided below.

Additional documentation can be found in the due diligence reports prepared by AECOM, Kleinfelder, and MBK provided in Appendices D, E, and F, respectively.
1) NEMDCEL Station 2986+50: NEMDC Extension transition downstream on NEMDC to the NEMDC North project included extending the cutoff wall to overlap the NEMDC North cutoff wall approximately 50 feet. This transition was reviewed and meets the geotechnical requirements of this criteria. (MBK, 2024c)
2) NEMDCEL Station 3001+50: NEMDC Extension transitions upstream on NEMDC to previous work including waterside slope flattening and crest widening. The NEMDC Extension reach included construction of a seepage cutoff wall that extended approximately 50 feet into an over widened levee section containing a waterside ramp. This transition was reviewed and meets the geotechnical requirements of this criteria. (MBK, 2024c) 3) NEMDCEL Station 3001+50 to 3029+00: Interface of UPRR embankment with NEMDCEL landside slope. This historic embankment was constructed prior to the levee. No past performance issues have been observed. This transition was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
4) NEMDCEL: Station 3001+50 to 3013+00: Interface of ditch at landside levee toe. No past performance issues have been observed. This transition was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
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18 5) NEMDCEL Station 3014+00: City of Sacramento Pumping Plant No. 153 is present landside of the UPRR embankment with one outfall pipe penetrating the levee. No past performance issues have been observed. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
6) NEMDCEL Station 3021+75: Transition from NEMDEL to West El Camino Avenue Stoplog Structure and bridge. This structure was reviewed and meets the geotechnical requirements of this criteria. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
7) NEMDCEL Station 3025+00: Interface of the NEMDCEL to a telecommunication vault. The vault is located on the levee crest. No past performance issues have been observed. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b) 8) NEMDCEL Station 3029+00 to 3034+00: Transition at end of seepage cutoff wall constructed at the waterside levee toe. This wall was extended downstream approximately 500 feet as a resilience measure to avoid potential future seepage remediation needs. This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) 9) NEMDCEL Station 3051+00: Transition at end of seepage cutoff wall and transition of UPRR to NEMDCEL embankment. A gap in remediation between the wall and UPRR was reviewed and determined to not require additional remediation. This transition was reviewed and meets the geotechnical requirements of this criteria. (AECOM, 2024) These overlaps and transitions are considered appropriate as discussed above for the NEMDC East Levee.

Therefore, the NEMDC east levee meets requirements for ULDC 7.9 Interfaces and Transitions.

AMERICAN RIVER NORTH LEVEE
A summary of the interface and transitions reviewed along the American River north levee are provided below. Additional documentation can be found in the due diligence reports prepared by Kleinfelder and MBK provided in Appendices E and F, respectively.
1) ARNL Station 3000+00: The ARNL seepage cutoff wall was extended through construction of another seepage cutoff wall extending up NEMDC. The newer, NEMDC wall included a 50-foot overlap of the previously constructed ARNL wall. This transition was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b) 2) ARNL Station 3013+10: The ARNL seepage cutoff wall discussed in item #1 above, terminated at Station 3013+10. A 70 foot long by 10-foot-wide drained gravel berm was constructed at this location to address end around affects. This transition was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
3) ARNL Station 3013+40 and ARNL Station 3014+25: Transition from ARNL to Del Paso Stoplog Structure on northwest and southeast. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
4) ARNL Station 3015+60 and ARNL Station 3016+00: Transition from ARNL to UPRR Stoplog Structure on northwest and southeast. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
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19 5) ARNL Station 3015+60 to 3016+00: Review of UPRR wooden Trestle Bridge Piles and the interface with ARNL. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
6) ARNL Station 3016+40 to 3018+00: Review of Highway 160 bridge support columns and north abutment interface with ARNL. This structure was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b)
7) ARNL Station 3019+00: Transition to seepage cutoff wall. This review indicates the wall overlaps the Highway 160 bridge abutment by 200-feet to address any end around affects. This transition was reviewed and meets the geotechnical requirements of this criteria. (Kleinfelder, 2024b) 8) ARNL Station 3051+00 to 3052+00: The NEMDC South project transition upstream on the American River north levee by extending the cutoff wall to overlap the existing American River north levee cutoff wall approximately 100 feet. This transition was reviewed and meets the geotechnical requirements of this criteria. (MBK, 2024c) and (Kleinfelder, 2024b) 9) ARNL Station 3548+00: American River north levee transitions to high ground at the Arden Way entrance to the American River Parkway. Surrounding high ground in this area is approximately a minimum of 6 feet above the design water surface elevation. This transition was reviewed and meets the geotechnical requirements of this criteria. (MBK, 2024c) 10) American River north levee includes dozens of construction features including slope flattening, crest widening and raising, long cutoff wall reaches, and short jet grout reaches to close windows.

The transitions and overlaps between these reaches were evaluated by USACE and accounted for during construction activities. This transition was reviewed and meets the geotechnical requirements of this criteria. (MBK, 2024c)
These overlaps and transitions are considered appropriate as discussed above for the American River North Levee. Additionally, the USACE 2014 letter provides a Statement of Performance which is applicable to interfaces and transitions.

Therefore, the American River north levee meets requirements for ULDC 7.9 Interfaces and Transitions.

ULDC 7.10: EROSION
Levees that pose an immediate erosional breaching hazard during either a flood or during normal flow conditions need to be repaired to meet ULDC. Similarly, levees that are likely to be significantly damaged during either a flood or normal flow condition should be protected with appropriate revetment. Erosion hazards are evaluated for the following conditions: 1) high-velocity flows coupled with erosive levee materials and/or poor hydraulic conditions; 2) large waves developed by wind over large, open bodies of water; and 3) boat wakes. MBK performed an evaluation of the levees and considered potential factors such as existing erosion, geomorphologic trends, streamflow velocity and inundation depths during high water, wind-wave shear stress, levee materials, encroachments and anomalies, bank protection, and vegetation (MBK, 2024a and 2024b). MBK Engineers performed a levee inspection to observe multiple topics related to Operation and Maintenance, including erosion on January 22, 2024 (MBK, 2024b).

ARCADE CREEK SOUTH LEVEE
Arcade Creek carries drainage from upstream foothill areas. However, the downstream portion of the creek becomes backwater once stages in the American River increase. As a result, flood velocities along URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

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20 the Arcade Creek south levee are generally below the threshold of concern and the maximum velocity was determined to be under 4.7 fps for the modeled event. The floodway for Arcade Creek is very narrow and significant waves are not expected to develop. The floodway is not conducive to boating, even during a flood event, and therefore boat wake erosion is not expected to occur. The calculated water velocities are equal or less than the maximum permissible velocities for either bare-earth or vegetated flow channels.

The embankment material, primarily silty clay, has a relatively low susceptibility to erosion. The condition of the existing levee is free of significant erosion. There are no major meanders, constrictions, or confluences in Arcade Creek. However, recent encampments have collected large amounts of debris within the channel which may redirect the flow of water and create erosive conditions. The O&M duties of the maintaining agency include providing patrols to observe and watch for adverse erosion conditions during a high water event.

The Arcade Creek south levee meets ULDC 7.10.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC carries drainage from upstream foothill areas. However, a majority of the NEMDC becomes backwater once stages in the American River increase. As a result, flood velocities along the NEMDC east levee are below the threshold of concern and the maximum velocity was determined to be under 3.3 fps for the modeled event. The floodway for NEMDC is very narrow and significant waves are not expected to develop. The floodway is not conducive to boating, even during a flood event, and therefore boat wake erosion is not expected to occur. The calculated water velocities are equal or less than the maximum permissible velocities for either bare-earth or vegetated flow channels. The embankment material, primarily silty clay, has a relatively low susceptibility to erosion. The condition of the existing levee is free of significant erosion. There are no major meanders, constrictions, or confluences in the NEMDC.

However, recent encampments have collected large amounts of debris within the channel which may redirect the flow of water and create erosive conditions. The O&M duties of the maintaining agency include providing patrols to observe and watch for adverse erosion conditions during a high water event.

The NEMDC east levee meets ULDC 7.10.

AMERICAN RIVER NORTH LEVEE
Segments of this levee vulnerable to erosion were previously mitigated with rock slope protection, launchable rock, plantings, or other solutions. Some of the projects are still in the process of being implemented. The potential for erosion along significant portions of the American River were considered high due to the foundation and levee fill material consisting predominately of relatively clean sands and gravels. The floodway for the American River is heavily vegetated and any waves which might develop are expected to be small and only exist for a short duration. The small wave action against a well vegetated waterside slope is expected to create little erosion that can be addressed as a part of O&M after a storm event. Boats are not expected in the floodway during a flood event and boat wake erosion is not expected to occur. Flood velocities along the American River north levee are generally below the threshold of concern and the maximum velocity was determined to be under 4.6 fps for the modeled event. The calculated water velocities are equal or less than the maximum permissible velocities for either bare-earth or vegetated flow channels. The floodway of the American River is fairly narrow and significant waves are not expected to develop. The condition of the existing levee is free of significant erosion. There are no major meanders, constrictions, or confluences in the NEMDC.

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21 The American River north levee meets ULDC 7.10.

ULDC 7.11: RIGHT-OF-WAY
As per ULDC, right-of-way criteria for levees and floodwalls in urban and urbanizing areas need to allow adequate room for maintenance, inspection, patrolling during high water, and flood-fighting; allow additional room to expand facilities in the future; and prohibit excavations and land modifications that would endanger the integrity of the levee or floodwall.

Specifically, the ULDC requires fee title or an easement for the entire levee prism extending to a minimum of 20 feet beyond the landside toe of the flood protection system for access and inspection. ULDC also allows for two alternatives where adjacent lands are developed: 1) rights for a minimum 10-foot-wide landside clear zone or 2) a 20-foot-wide landside visibility zone. Furthermore, waterward of the levee prism, where there is sufficient area to do so without resulting in the loss of sensitive riparian habitat, consideration should be given to acquiring a 15-foot-wide zone.

In addition to the minimums required by the ULDC for access and inspection, the ULDC recommends acquiring right-of-way that has a width equal to at least four times the levee height or 50 feet, whichever is greater, on the landside of the 20-foot clear zone for longer-term flood protection.

Lastly, the ULDC recommends that the city or county adopt restrictions on excavations within 200 to 400 feet, depending on the levee height.

As part of its levee improvement program, SAFCA has worked to acquire land associated with the levee embankment, O&M corridors, and/or other flood control features. The entire American River north urban levee system meets ULDC for right-of-way. However, there are some portions of the levees where 20-foot fee title right-of-way landward of the levee was not possible, and in these areas, right-of-way is met through either a reduced landside right-of-way in fee or easement and/or the presence of a 20 foot “free and clear” zone. Wherever feasible, SAFCA also acquired waterside rights and rights to the levee footprint.

Figures provided in Appendix H show the right-of-way acquired in fee-title and easement right-of-way for the levees. Despite the levee system meeting ULDC for right-of-way, the goal is to acquire long-term rights (i.e., fee-title or easement) in locations where there is not currently 20-feet at the landside toe.

These locations are identified in the recommended American River north levee system Right-of-Way Plan in Appendix J. The land use agency will need to adopt this plan or revise based on their planning needs and create a Right-of-Way Implementation Plan. In 2013, the City of Sacramento adopted a grading ordinance (Ordinance 2013-0020 Section 1; Ordinance 2013-0007 Section 1) outlined in Title 17, Division II, Article III (17.200.340 F zone - Setbacks) that restricts any grading activity within 50 feet of the levee.

Sacramento County has adopted a similar ordinance found in Sacramento County Zoning Code Section

4.7.3 Development Standards, specifically for Lots Protected by Levees (Section 4.7.3.A) which restricts construction of structures to no closer than 25 feet from the landside levee toe.

ARCADE CREEK SOUTH LEVEE
The Arcade Creek south levee and O&M corridors are located within lands owned by the City of Sacramento, Western Pacific Railroad Co., ARFCD, and private owners. Where fee or easement is not present for the 20-foot landside corridor, either a reduced landside right-of-way corridor and/or 20 foot URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
22 “free and clear” zone are present, as shown on figures provided in Appendix H and in the Right of Way Plan in Appendix J2.

The Arcade Creek south levee meets ULDC 7.11.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The NEMDC east levee and O&M corridors are located within lands owned by City of Sacramento, County of Sacramento, Reclamation District 1000, Western Pacific Railroad Co., Union Pacific Railroad Co., ARFCD, and private owners. Where fee or easement is not present for the 20-foot landside corridor, either a reduced landside right-of-way corridor and/or 20-foot “free and clear” zone are present, as shown on figures provided in Appendix H and in the Right of Way Plan in Appendix J2.

The NEMDC east levee meets ULDC 7.11.

AMERICAN RIVER NORTH LEVEE
The American River north levee and O&M corridors are located within lands owned by City of Sacramento, County of Sacramento, Sacramento Regional County Sanitation District, State of California, Southern Pacific and Western Pacific, and private owners. Where fee or easement is not present for the 20-foot landside corridor, either a reduced landside right-of-way corridor and/or 20 foot “free and clear” zone are present, as shown on figures provided in Appendix H and in the Right of Way Plan in Appendix J2.

The American River north levee meets ULDC 7.11.

ULDC 7.12: ENCROACHMENTS
ULDC 7.12 requires an assessment of each existing encroachment, permitted or not, to determine the encroachment’s impact on the reliability of levee performance. The evaluation of encroachments considers the following: age, type, condition, performance history, impacts on the levee structural integrity, impacts on the hydraulic effect of the channel, and impacts on the O&M of the levee.

A summary of Encroachments along with the methodology used following USACE, ULDC, and CVFPB guidelines is included in Appendix I (Mead & Hunt, 2024a). Additionally, MBK Engineers performed a site visit to observe general conditions related to Operation and Maintenance, including encroachments, on January 22, 2024. Observations from this visit are summarized in a letter provided in Appendix G (MBK, 2024b) and all observed encroachments were consistent with prior evaluations with none being considered high-risk.

In 2013, SAFCA performed inventory of encroachments along ANLS. In December 2023 SAFCA conducted field investigations to verify and update existing encroachment data. There are nearly 600 encroachments summarized in Appendix I, not including penetrations or associated structures, closure structures, retaining walls, or floodwalls. None of these were determined to pose a risk to levee integrity or reliability of the levee to perform under the full loading condition up to the HTOL. No high-risk encroachments were identified, that would fall within categories 1A, 1B, or 2, as described in the Encroachment White URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
23 Paper (Mead & Hunt, 2014), within this levee system. It should be noted that the high number of encroachments is due to adjacent urban development in near proximity to the landside levee toe including some residential landscaping on the landside levee slope. A framework for an encroachment remediation plan is included in Appendix J7 to address the low and moderate risk items identified by being non-compliant and non-permitted, as required by ULDC. The land use agency will need to use this framework to create and adopt an encroachment remediation plan.

Therefore, the American River north levee system meets ULDC 7.12.

ULDC 7.13: PENETRATIONS
ULDC 7.13 requires a hazard assessment of each existing penetration, permitted or not, to determine the penetration’s impact on the reliability of levee performance. If penetrations are considered high-hazard, additional evaluation and action are required. For other existing penetrations that are not considered to be high-hazard, but have not been permitted, the City or County is required to have a remediation plan in place, or reference such a plan, for the entire length of levee that the finding is to cover.

A summary of Penetrations along with the methodology used is included in Appendix I (Mead & Hunt, 2024a).

There are over 240 penetrations summarized in Appendix I. A few of these require an exception due to structural evaluation (1 penetration), age of pipes (36 penetrations), and permits not found (4 penetrations). In addition, up to 95 penetrations are being tracked as requiring submittal of inspection documentation, although many of these penetrations are reported as having recent inspections. The workplans include a plan and timeframe for obtaining the necessary information and confirming/ performing engineering evaluations. None of these are anticipated to pose a risk to levee integrity or reliability of the levee to perform under the full loading condition up to the HTOL, if the workplans and monitoring are completed as indicated in Appendix J. A framework for penetration remediation plan is included in Appendix J3 to address these items, as required by ULDC. The land use agency will need to use this framework to create and adopt a penetration remediation implementation plan.

Therefore, the American River north levee system meets ULDC 7.13 through exception.

ULDC 7.14: FLOODWALLS, RETAINING WALLS, AND CLOSURE

STRUCTURES
This section describes the levee documentation and general requirements for ULDC 7.14 Floodwalls, Retaining Walls, and Closure Structures.
“Current USACE design guidance for special features such as floodwalls, retaining walls, and closure structures is to be followed. This information is included in EM 1110-2-1913, EM 1110-2-2502, EC 1110-2-6067, and ETL 1110-2-571. Because design considerations for floodwalls and closure structures are still evolving since the 2005 New Orleans flood, caution should be used when designing and assessing these structures. All global slope stability and embankment through- URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

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24 seepage and underseepage safety criteria requirements are applicable for floodwalls, retaining walls, and closure structures on levees.

For closure structures, the civil engineer needs to provide the following information: maintaining entity, levee mile, Global Positioning System coordinates, Board permit number (if applicable), structure details, length of time to close structure, location and type of materials for closure, structure dimensions, age, and performance history.

Closure structures need to be tested at least once a year before the flood season so that crews responsible for implementing the structures are familiar with their operation and to provide assurance that all parts are present and in working order.”

ARCADE CREEK SOUTH LEVEE
Closure structures are located at the following locations (AECOM, 2024 and Mead & Hunt, 2024a):
• ACSL Station 4001+00: UPRR Stoplog Structure
Floodwalls are located at the following locations (AECOM, 2024):
• ACSL Station 4067+10 to 4067+50: Downstream of Rio Linda Boulevard bridge, extending approximately 40 feet, with a height up to 2 feet.
• ACSL Station 4068+40 to 4110+00: Upstream of Rio Linda Boulevard bridge, extending approximately to Marysville Boulevard with a height up to 3 feet.

A structural condition assessment and analysis review of these floodwalls was completed by Mead & Hunt (2024a) and were found to be well maintained and in a serviceable condition for their intended use.

There are no retaining walls used for flood control, however, there are retaining wall structures at the landside toe adjacent to the City of Sacramento Pump Station yards and two private residences. These features are discussed as part of ULDC 7.14 Floodwall, Retaining Walls, and Closure Structures, provided by Mead & Hunt (2024a).

Additionally, Mead & Hunt (2024a) evaluated the structural adequacy of the closure structure and concluded it is in good working order and there are no anticipated impacts to the reliability of the levee performance under the HTOL loading condition. However, the operation frequency for activating the UPRR stoplog structures is currently being performed at 5-year increments in order to minimize impacts to UPRR. The ULDC criteria outlines yearly activation. Upon review of the City of Sacramento Emergency Response Plan, prior installation/activation reports, and inventoried items an exception is requested with the following justification. This exception is to extend the activation period from annually to a full activation not more than every 5 years. The City of Sacramento performs annual review of materials, procedures, and inspects the structure. Additionally, the prior trial closures have been performed without incident. Additional documentation for this exception may be found in Appendix I (Mead & Hunt, 2024a).

Therefore, these structures on the Arcade Creek south levee meet ULDC 7.14 through exception.

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25 NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
Floodwalls are located upstream and downstream of the West El Camino bridge with a height of up to 3 feet, extending approximately 85 feet on either side of the bridge. According to Mead & Hunt (2024a), this floodwall replaced the stop log structure described above. A structural review of the floodwall was performed by Mead & Hunt (2024a) and was found to be well maintained and in a serviceable condition for their intended use.

There are no retaining walls used for flood control, however, there is one retaining wall structure at the landside toe of the ramp to Railroad Drive. These features are discussed as part of ULDC 7.14 Floodwalls, Retaining Walls, and Closure Structures, provided by Mead & Hunt (2024a).

There are no closure structures within this levee reach.

Therefore, these structures on the NEMDC east levee meet ULDC 7.14.

AMERICAN RIVER NORTH LEVEE
Closure structures are located at the following locations (Kleinfelder, 2024b, Mead & Hunt, 2024a, and MBK, 2024c):
• ARNL Station 3014+00: Del Paso Avenue Closure Structure • ARNL Station 3016+00: UPRR Stoplog Structure
There are no floodwalls or retaining walls used for flood control. However, there is a waterside retaining wall for the railroad embankment interface with the levee embankment, landside toe retaining walls at the County Howe Avenue (D-05) and Wilhaggin (D-43) Pump Stations, and one retaining wall at the landside toe for the bike trail under the Fair Oaks Boulevard bridge. These features are discussed as part of ULDC

7.14 Floodwalls, Retaining Walls, and Closure Structures, provided by Mead & Hunt (2024a).

Additionally, Mead & Hunt (2024a) evaluated the structural adequacy of these structures and concluded they are in good working order and there are no anticipated impacts to the reliability of the levee performance under the HTOL loading condition. However, the operation frequency for activating the UPRR stoplog structures is currently being performed at 5-year increments in order to minimize impacts to UPRR. The ULDC criteria outlines yearly activation. Upon review of the City of Sacramento Emergency Response Plan, prior installation/activation reports, and inventoried items an exception is requested with the following justification. This exception is to extend the activation period from annually to a full activation not more than every 5 years. The City of Sacramento performs annual review of materials, procedures, and inspects the structure. Additionally, the prior trial closures have been performed without incident. Additional documentation for this exception may be found in Appendix I (Mead & Hunt, 2024a).

Therefore, these structures on the American River north levee meet ULDC 7.14 through exception.

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26 ULDC 7.15: ANIMAL BURROWS
Borrowing animals can present a significant threat to levee integrity and, therefore, proactive animal control and damage repair are required as part of levee maintenance.

ARFCD follows a rodent control and abatement program included in Appendix J4 (ARFCD, 2017) to maintain constant observation and deterrence of burrowing animals which are present in the American River North Basis levee system. The rodent control and abatement program tracks active burrows as well as the monthly abatement activity. ARFCD is vigilant in inspecting for burrowing animals and reacting quickly to repair any damage to the levees. MBK Engineers performed a site visit to observe general conditions related to Operation and Maintenance, including animal burrows, on January 22, 2024.

Observations from this visit are summarized in a letter provided in Appendix G (MBK, 2024b) and no indications of burrowing rodent activity were observed in that inspection. Additionally, the USACE Routine Inspection Report (USACE, 2020) provided a review of animal control and rated the system Minimally Acceptable (M). We understand a more recent Routine Inspection was performed, but the report has not been finalized for circulation at the time of publication of this report.

Therefore, the entire American River North levee system meets ULDC 7.15.

ULDC 7.16: LEVEE VEGETATION
ULDC 7.16.1 requires an engineering inspection and evaluation to identify trees and other woody vegetation on the levee and within 15 feet of the levee toe that pose an unacceptable threat to the integrity of the levee. Those posing an unacceptable threat are to be removed; those not posing an unacceptable threat need not be removed. Non-hazardous vegetation is allowed to remain because they do not pose an unacceptable threat but must be trimmed and thinned for access and visibility. The USACE Periodic Inspection Report (USACE, 2010) provided a review of unwanted vegetation growth and rated the system Minimally Acceptable (M) along NEMDC and Unacceptable (U) along Arcade Creek south levee and American River north levee. We understand a more recent Routine Inspection was performed, but the report has not been finalized for circulation at the time of publication of this report. Conversations with ARFCD indicate they have worked diligently to remove and address the unacceptable vegetation identified in the 2010 USACE inspection and expect a higher rating to be published in the upcoming inspection report. This information is consistent with observations from MBK Engineers site visit on January 22, 2024 to view general conditions related to Operation and Maintenance, including vegetation.

Observations from this visit are summarized in a letter provided in Appendix G (MBK, 2024b). Some woody vegetation is present in the upstream segment of Arcade Creek north levee; however, this is considered acceptable as the trees are randomly spaced and do not affect visibility and/or flood fighting.

Therefore, the entire American River North levee system meets ULDC 7.16.

ULDC 7.17: WIND SETUP AND WAVE RUNUP
ULDC 7.17 requires a wind-wave analysis. The wind setup and wave runup distances must be computed and when added to the median 200-year still WSE the resultant shall be no more than the MTOL.

Additionally, wind setup and wave runup must also be considered for analysis of erosion and overtopping impacts.

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27 The formation and magnitude of wind-generated waves against shoreline structures is controlled by the physical conditions present on and near the shore such as slope and roughness of the structure, wind speed, and distance over which wind blows (fetch length). The Wind Wave Analysis determined the wind setup and the runup for the 2 percent exceedance wave (wave runup which is exceeded by 2 percent of waves on average) comes from USACE (2010). The analyses were performed at the location on the levees expected to generate the largest wind setup and wave runup.

ARCADE CREEK SOUTH LEVEE
The Arcade Creek south levee was evaluated for wind setup and wave runup with expected ranges of approximately 0.9 to 1.2 feet (Mead & Hunt, 2024b).

The wind-wave analysis for the Arcade Creek south levee meets the ULDC 7.17 requirements.

NATOMAS EAST MAIN DRAINAGE CANAL EAST LEVEE – ARCADE CREEK TO

AMERICAN RIVER
The Natomas East Main Drainage Canal east levee was evaluated for wind setup and wave runup with expected ranges of approximately 1.6 to 3.0 feet (Mead & Hunt, 2024b).

The wind-wave analysis for the NEMDC east levee meets the ULDC 7.17 requirements.

AMERICAN RIVER NORTH LEVEE
The American River north levee was evaluated for wind setup and wave runup with expected ranges of approximately 1.6 to 3.0 feet (Mead & Hunt, 2024b).

The wind-wave analysis for the American River north levee meets the ULDC 7.17 requirements.

ULDC 7.18: SECURITY
ULDC 7.18 requires a security plan to protect urban and urbanizing area levee systems from acts of terrorism and other malicious or negligent acts. The security plan is to identify security personnel, responsibilities, resources, and measures. In developing the security plan, the agency/agencies responsible for levee maintenance must consider and prioritize vulnerabilities and employ an array of security measures from four basic categories to address vulnerabilities: networked detection (criterion 7.18.1); deterrence (criterion 7.18.2); physical security (criterion 7.18.3); and intrusion interdiction (criterion 7.18.4) during high-threat periods.

American River Flood Control District utilizes a Security Plan (ARFCD, 2024) in addition to a Flood Safety Plan and an Emergency Action Plan (ARFCD, 2018). The Security Plan describes security personnel, their responsibilities, the resources available to cope with various emergencies, and measures applicable to each type of emergency or security threat. This plan is closely coordinated with the Sacramento County Regional Park Rangers along the American River and with the City of Sacramento Police Department along NEMDC and Arcade Creek to help prevent unauthorized access and to remove and arrest those URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
28 who are observed in vandalizing the levees and security measures. It is also closely coordinated with the local firefighting agencies to assist in addressing the several instances of fires which occur in the dry valley conditions during the summer. Locked gates, security fences, signage, and outlined patrol frequency are also outlined in the Security Plan. The levee system specific security plan is provided in Appendix J5.

Therefore, the American River North levee system has adequate plans and features to address the security of the levee system and meets ULDC 7.18.

ULDC 7.19: SEA LEVEL RISE
ULDC 7.19 requires that the effects of sea level rise be estimated and addressed for the duration during which a ULOP Finding may be valid. The sea level rise projection estimated by the State of California Department of Water Resources (DWR) in the 2022 Central Valley Flood Protection Plan (CVFPP) Update (DWR, 2022), which was based on the State of California Sea-Level Rise Guidance 2018 Update (OPC, 2018), was used for the analysis.

The 2022 CVFPP used a 50-year sea level rise projection of 3.68 feet at San Francisco. DWR computed the effects of this sea level rise throughout the Sacramento-San Joaquin Delta with the RMA Bay-Delta model.

Stage hydrographs computed by the RMA Bay-Delta model were used as downstream boundaries in the ULDC hydraulic analysis. The duration of the ULOP Finding is 20-years; therefore, the use of a 50-year sea level rise projection is a conservative application.

The American River North levee system meets ULDC 7.19.

ULDC 7.20: EMERGENCY ACTIONS AND FLOOD SAFETY
PLANS
ULDC 7.20 includes requirements for preparing flood safety plans, as it is important that local maintaining agencies and communities understand the responsibilities of flood risk management within their jurisdictions. Specifically, the ULDC requires each public agency with the responsibility for public safety for residents protected by levees and floodwalls to have a plan for flood events and other natural or manmade, flood-related, incidents that could result in human casualties, property destruction, and economic losses.

Several agencies, including ARFCD, City of Sacramento, and County of Sacramento, have the responsibility for the public safety of residents protected by the American River North levee system. ARFCD, with primary responsibility for the levee system, has a Flood Safety Plan (ARFCD, 2018), Appendix J6, that outlines their planned response to flood emergencies affecting their levee systems. This plan meets the requirements of California Water Code, Section 9650; and relies on the similar plans adopted by the City (City of Sacramento, 2018 and 2020) and County (Sacramento County, 2022). No changes to the 2018 plan have been made and this is considered the most current version of the Flood Safety Plan.

The American River North levee system’s performance during a 200-year flood event relies on the operation of flap gates and positive closure valves at drainage crossings, installation of the stoplog structure at the UPRR, and operation of the emergency isolation gates at NEMDC stormwater pumping URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
29 plant, in addition to the performance of the levee. These features are identified in the O&M Manual for the levee system. The City and County of Sacramento are responsible for operation and maintenance of these features, which are documented in their respective Emergency Operations Plans.

The American River North levee system meets ULDC 7.20 for Emergency Actions.

ULDC 8.0 OPERATIONS & MAINTENANCE
ULDC 8.0 includes requirements related to operations and maintenance. Specifically, ULDC requires:
 The levee system must have an operation and maintenance manual consistent with USACE requirements, including inspection requirements, except as may be appropriate to deviate from those requirements to comply with the ULDC.
 The facilities providing the urban level of flood protection be operated and maintained by a public agency with the authority and resources to do so.  Damage and maintenance inadequacies identified from inspections should be prioritized and addressed in a timely manner, not awaiting the periodic review process.  Monitoring during high water needs to provide for a thorough visual inspection of both the waterside and landside levee slope (and landside berm toe area) at intervals of no more than 1 hour.
 Plans required under ULDC 7.18 for security, and ULDC 7.20 for flood safety; other plans, such as a post-earthquake remediation plan, right-of- way plan, encroachment remediation plan, penetration remediation plan, or flood relief plan be in-place, as applicable.

This levee system is included in USACE Supplement to Standard Operation and Maintenance Manual (O&M Manual), Sacramento River Flood Control Project, Unit No. 118 – Part No. 2. North Levee of American River, East Levee of Natomas Canal, Both Levees of Arcade Creek, South Levee of Linda Creek and Magpie Creek Diversion Channel, revised date 28 Jan 2023. As previously indicated, this levee system is maintained by the ARFCD, and the City of Sacramento maintains and operates the UPRR and West El Camino Avenue stoplog structures and Del Paso closure structure. The City of Sacramento maintains and operates the various pump stations and drainage culverts adjacent to the American River North levee system. The manuals for these pump stations were reviewed and found to be consistent with the facility operations and maintenance needs. ARFCD performs inspections and patrols as outlined in the O&M Manual and addresses damage and maintenance issues as they arise. A security plan and flood safety plan are in place as described in relevant sections above. Mead and Hunt provided a review of the referenced manuals and includes a discussion in Appendix I. Additionally, MBK Engineers performed a site visit on January 22, 2024 to view general conditions related to Operation and Maintenance. Observations from this visit are summarized in a letter provided in Appendix G (MBK, 2024b).

The American River north levee system meets ULDC 8.0 for Operations and Maintenance.

6.0 BIBLIOGRAPHY
As mentioned in Chapter 1, this Engineer’s Report relies on dozens of other documents, reports, analyses, and evaluations. Many of these are listed in the following bibliography; however, this bibliography is URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
30 mostly limited to presenting the substantial evidence required to demonstrate that an urban level of flood protection exists. Items shown BOLD are included as appendices to this report. (ARFCD, 2018). American River Flood Control District Flood Safety Plan, as required by California Water Code 9650. January 2018. (Appendix J6)
(ARFCD, 2017). American River Flood Control District Rodent Control & Abatement Program.

Revised October 2017. (Appendix J4)
(ARFCD, 2024). American River Flood Control District Security Plan – American River North Levee System. March 2024. (Appendix J5)
(AECOM, 2024) North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00. July 22, 2024. (Appendix D)
(Kleinfelder, 2013a). Problem Identification Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream Of American River, and Beach Lake Levee). Sacramento County, California. September 18, 2013. (Kleinfelder, 2013b). Geotechnical Data Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee). Sacramento County. May 31, 2013.
(Kleinfelder, 2015). Draft ULDC Geotechnical Results Summary, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee). Sacramento County, California. December 18, 2015. (Kleinfelder, 2024a) Seismic Performance Summary Report, North Area Streams Levee Areas, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento County, California. September 12, 2024. (Appendix E, sub-Appendix C) (Kleinfelder, 2024b) ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00 & NEMDC East Levee Station 3001+50 to 3029+00. September 12, 2024. (Appendix E) (Kleinfelder, 2024c) Post Earthquake Remediation Plan, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento County, California, October 2024 (Appendix J1)
(MBK, 2014). SAFCA Levee Certification Erosion Report. Sacramento, California. 2014. (MBK, 2016a). Technical Memorandum. Overview of High Hazard Encroachments to Support Adequate Progress Towards an Urban Level of Flood Protection. Sacramento, California. April 15, 2016. (MBK, 2016b). Technical Memorandum. Overview of High Hazard Vegetation to Support Adequate Progress Towards an Urban Level of Flood Protection. Sacramento, California. April 15, 2016.

URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
31 (MBK, 2024a) American River North Levee System- Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee. July 1, 2024. (Appendix C)
(MBK, 2024b) SAFCA American River North Levee System, Levee O&M Review in Support of FEMA and ULDC Certification. February 22, 2024. (Appendix G) (MBK, 2024c) Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – Arcade Creek South Levee, NEMDC East Levee, and American River North Levee; American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50 SAFCA FEMA and ULDC Evaluation, Sacramento County, CA. September 11, 2024. (Appendix F)
(MBK, 2024d) Right of Way Plan – American River North. August 2024 (Appendix J2). (Mead & Hunt, 2014). Sacramento FEMA Certification White Paper for Addressing Encroachments. July 21, 2014.
(Mead & Hunt, 2015). City of Sacramento North Area Union Pacific Railroad (UPRR) Stop Log Structure Trial Installation Assessment. Technical Memorandum. September 25, 2015. (Mead & Hunt, 2017). Structural Calculations, NEMDC Pump Station: Floodwalls, Sacramento, CA.

December 8, 2017.
(Mead & Hunt, 2024a) American North Levee System Due Diligence Review for ULDC & FEMA Certification. September 13, 2024. (Appendix I)
(Mead & Hunt, 2024b) ANLS Wind Setup and Wave Runup Analysis. September 13, 2024. (Appendix I, sub–Appendix D)
(Mead & Hunt, 2024c) Technical Memorandum, Penetration Exceptions Work Plan, American River North Levee System SAFCA Due Diligence Review for Urban Levee Design Criteria Section 7.13, August 27, 2024 (Appendix J3)
(Psomas, 2024) O&M Right of Way Map, American River North Levee System. August 2024. (Appendix H)
(SAFCA, 2015). Sacramento Federal Emergency Management Agency Certification White Paper for Addressing Encroachments. August 6, 2015.
(URS, 2008). Levee Seismic Vulnerability Assessment Methodology Report. 2008. (URS, 2009). Geotechnical Levee Practice Standard Operating Procedures. [USACE Sacramento Districts].

Sacramento, California. 2009.
(URS, 2010). Modified Supplemental Geotechnical Data Report (MSGDR), Natomas East Main Drainage Canal (NEMDC) West Study, Urban Levee Geotechnical Evaluations Program Contract 4600007418 and 4600008101. [Department of Water Resources]. November 2010.

URBAN LEVEL OF FLOOD PROTECTION ENGINEER’S REPORT

AMERICAN RIVER NORTH LEVEE SYSTEM
32 (URS, 2015a). Geotechnical Evaluation Report, Volume 1, Existing Conditions, Natomas East Main Drainage Canal, West Study Area, Urban Levee Evaluations Project, Contract 4600008101. [Department of Water Resources]. January 2015.
(URS, 2015b). Geotechnical Evaluation Report (Existing Conditions and Seismic Assessment), Natomas North Study Area, Urban Levee Evaluations Project, Contract 4600008101. [Department of Water Resources]. March 2015.

Appendix A.

American River North ULDC
Consultant Certification Statements
ENGINEER’S OPINION
ULDC 7.1: DESIGN WATER SURFACE ELEVATION
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  American River North Levee System – Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee, prepared by MBK Engineers, dated July 1, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.1 Design Water Surface Elevation, as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Don Trieu, PE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
_________________________________________________7/1/2024 Signature Date
Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.2: MINIMUM TOP OF LEVEE
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  American River North Levee System - Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee, prepared by MBK Engineers, dated July 1, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.2 Minimum Top of Levee, as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Don Trieu, PE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
__________________________________________________7/1/2024____ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.3: SOIL SAMPLING, TESTING, AND LOGGING
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated July 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC 7.3 Soil Sampling, Testing and Logging through exception, as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Richard Millet, PE
AECOM
2020 L Street
Sacramento, CA 95811
___________________________________________________________________ Signature Date Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.3: SOIL SAMPLING, TESTING, AND LOGGING
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.3 Soil Sampling, Testing and Logging through exception as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
___________________________________________________________________ Signature Date Not Valid Unless Stamped
September 20, 2024
ENGINEER’S OPINION
ULDC 7.3: SOIL SAMPLING, TESTING, AND LOGGING
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50; SAFCA FEMA and ULDC Evaluation; Sacramento County, California, prepared by MBK Engineers, dated September 11, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.3 Soil Sampling, Testing and Logging through exception, as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Rebecca L. Money, PE, GE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
__________________________________________________9/11/2024 Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.4: SLOPE STABILITY FOR INTERMITTENTLY

LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.4 Slope Stability for Intermittently Loaded Levees as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
________________________________________________________ Signature Date Not Valid Unless Stamped
September 20, 2024 Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.4: SLOPE STABILITY FOR INTERMITTENTLY

LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated July 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.4 Slope Stability for Intermittently Loaded Levees as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Richard Millet, PE
AECOM
2020 L Street
Sacramento, CA 95811
___________________________________________________________________ Signature Date Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.4: SLOPE STABILITY FOR INTERMITTENTLY

LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50; SAFCA FEMA and ULDC Evaluation; Sacramento County, California, prepared by MBK Engineers, dated September 11, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.4 Slope Stability for Intermittently Loaded Levees as described in the above reference document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Rebecca L. Money, PE, GE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
___________________________________________ ___9/11/2024_____ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.5: UNDERSEEPAGE FOR INTERMITTENTLY

LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or reference in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated July 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.5 Underseepage for Intermittently Loaded Levees, as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Richard Millet, PE
AECOM
2020 L Street
Sacramento, CA 95811
___________________________________________________________________ Signature Date Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.5: UNDERSEEPAGE FOR INTERMITTENTLY

LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levees will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.5 Underseepage for Intermittently Loaded Levees as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
___________________________________________________________________ Signature Date Not Valid Unless Stamped
September 20, 2024 Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.5: UNDERSEEPAGE FOR INTERMITTENTLY

LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50; SAFCA FEMA and ULDC Evaluation; Sacramento County, California, prepared by MBK Engineers, dated September 11, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.5 Underseepage for Intermittently Loaded Levees, as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Rebecca L. Money, PE, GE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
________________________________________________9/11/2024____ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.6: FREQUENTLY LOADED LEVEES
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Sacramento Area Flood Control Agency; Urban Level of Flood Protection Engineer’s Report for the American River North Levee System, prepared by SAFCA, dated October 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.6 Frequently Loaded Levees, as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
____________________________________________ 10/1/2024___ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.7: SEISMIC VULNERABILITY
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levees will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.7 Seismic Vulnerability as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
___________________________________________________________________ Signature Date Not Valid Unless Stamped
September 20, 2024
ENGINEER’S OPINION
ULDC 7.8: LEVEE GEOMETRY
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated July 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC 7.8 Levee Geometry as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Richard Millet, PE, GE
AECOM
2020 L Street
Sacramento, CA 95811
___________________________________________________________________ Signature Date
Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.8: LEVEE GEOMETRY (GEOTECHNICAL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC 7.8 Levee Geometry for geotechnical requirements as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
___________________________________________________________________ Signature Date
Not Valid Unless Stamped
September 20, 2024
ENGINEER’S OPINION
ULDC 7.8: LEVEE GEOMETRY
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50; SAFCA FEMA and ULDC Evaluation; Sacramento County, California, prepared by MBK Engineers, dated September 11, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC 7.8 Levee Geometry as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Rebecca L. Money, PE, GE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
____________________________________________9/11/2024
Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.9: INTERFACES AND TRANSITIONS
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated July 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.9 Interfaces and Transitions, as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Richard Millet, PE, GE
AECOM
2020 L Street
Sacramento, CA 95811
___________________________________________________________________ Signature Date Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.9: INTERFACES AND TRANSITIONS (GEOTECHNICAL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.9 Interfaces and Transitions for geotechnical requirements as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
___________________________________________________________________ Signature Date Not Valid Unless Stamped
September 20, 2024
ENGINEER’S OPINION
ULDC 7.9: INTERFACES AND TRANSITIONS
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50; SAFCA FEMA and ULDC Evaluation; Sacramento County, California, prepared by MBK Engineers, dated September 11, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.9 Interfaces and Transitions as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Rebecca L. Money, PE, GE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
__________________________________________________9/11/2024______ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.10: EROSION
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following document forms the basis of this opinion.  SAFCA American River North Levee System; Levee O&M Review in Support of FEMA and ULDC Certification, prepared by MBK Engineers, dated February 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.10 Erosion as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
__________________________________________________02/22/2024_______ Signature Date
Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.11: RIGHT-OF-WAY
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  O&M Right of Way Map; American River North Levee, prepared by Psomas, dated March 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.11 Right-of-Way as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
___________________________________________________04/03/2024________ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.12: ENCROACHMENTS
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following document forms the basis of this opinion.  SAFCA American River North Levee; Levee O&M Review in Support of FEMA and ULDC Certification, prepared by MBK Engineers, dated February 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.12 Encroachments as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
___________________________________________________02/22/2024__ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.12: ENCROACHMENTS (CIVIL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in and evaluated in the following document forms the basis of this opinion.  American River North Levee System; Due Diligence Review for ULDC & FEMA Certification, prepared by Mead & Hunt, dated September 13, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.12 Encroachments as described in the above-referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Stephen R. Sullivan, PE
Mead & Hunt
180 Promenade Circle, Suite 240
Sacramento, CA 95834
___________________________________________________________________ Signature Date Not Valid Unless Stamped
September 13, 2024
ENGINEER’S OPINION
ULDC 7.13: PENETRATIONS (GEOTECHNICAL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated JUly 22, 2024 LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.13 Penetrations as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge;
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices;
 the structural works are designed in accordance with sound engineering practices to provide protection from the 200-year ULDC event; and
 the structural works are in place and functioning as intended for the 200-year ULDC event.

Richard Millet, PE, GE
AECOM
2020 L Street
Sacramento, CA 95811
____________________________________________________________ Signature Date Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.13: PENETRATIONS
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following document forms the basis of this opinion.  American River North Levee System; Due Diligence Review for ULDC & FEMA Certification, prepared by Mead & Hunt, dated September 13, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.13 Penetrations as described in the above-referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge;
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices;
 the structural works are designed in accordance with sound engineering practices to provide protection from the 200-year ULDC event; and
 the structural works are in place and functioning as intended for the 200-year ULDC event.

Stephen R. Sullivan, PE
Mead & Hunt
180 Promenade Circle, Suite 240
Sacramento, CA 95834
______________________________________________________________ Signature Date Not Valid Unless Stamped
September 13, 2024
ENGINEER’S OPINION
ULDC 7.14: FLOODWALLS, RETAINING WALLS, AND

CLOSURE STRUCTURES (GEOTECHNICAL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  North Area Streams ULDC Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, prepared by AECOM, dated July 22, 2024 LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.14 Floodwalls, Retaining Walls, and Closure Structures for geotechnical requirements as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge;
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices;
 the structural works are designed in accordance with sound engineering practices to provide protection from the 200-year ULDC event; and
 the structural works are in place and functioning as intended for the 200-year ULDC event.

Richard Millet, PE, GE
AECOM
2020 L Street
Sacramento, CA 95811
___________________________________________________________________ Signature Date Not Valid Unless Stamped
09/20/2024
ENGINEER’S OPINION
ULDC 7.14: FLOODWALLS, RETAINING WALLS, AND

CLOSURE STRUCTURES (GEOTECHNICAL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  ULDC Geotechnical Finding – American River North Levee Station 3000+00 to 3051+00, & NEMDC East Levee Station 3001+50 to 3029+00; Sacramento Area Flood Control Agency; Sacramento County, California, prepared by Kleinfelder, dated September 12, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions at the time the work was performed.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.14 Floodwalls, Retaining Walls, and Closure Structures for geotechnical requirements as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge;
 the analyses supporting this opinion have been performed in accordance with DWR’s ULDC and/or sound engineering practices;
 the structural works are in place and functioning as intended for the 200-year ULDC event.

Timothy Williams, PE
Kleinfelder
3130 Kilgore Road, Suite 200
Rancho Cordova, CA 95670
___________________________________________________________________ Signature Date
Not Valid Unless Stamped
September 20, 2024
ENGINEER’S OPINION
ULDC 7.14: FLOODWALLS, RETAINING WALLS, AND CLOSURE STRUCTURES (CIVIL) This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following document forms the basis of this opinion.  American River North Levee System; Due Diligence Review for ULDC & FEMA Certification, prepared by Mead & Hunt, dated September 13, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the Arcade Creek South Levee and American River North Levee segments of the subject levee system meets the requirements of the ULDC for Section 7.14 Floodwalls, Retaining Walls, and Closure Structures through exception as described in the above-referenced document; the Natomas East Main Drainage Canal East Levee – Arcade Creek to American River segment meet the requirements as described in the above-referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge;
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices;
 the structural works are designed in accordance with sound engineering practices to provide protection from the 200-year ULDC event; and
 the structural works are in place and functioning as intended for the 200-year ULDC.

Stephen R. Sullivan, PE
Mead & Hunt
180 Promenade Circle, Suite 240
Sacramento, CA 95834
___________________________________________________________________ Signature Date Not Valid Unless Stamped
September 13, 2024
ENGINEER’S OPINION
ULDC 7.14: FLOODWALLS, RETAINING WALLS, AND

CLOSURE STRUCTURES (GEOTECHNICAL)
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin – American River North Levee Station 3051+00 to 3548+50 and NEMDC East Levee Station 2986+50 to 3001+50; SAFCA FEMA and ULDC Evaluation; Sacramento County, California, prepared by MBK Engineers, dated September 11, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.14 Floodwalls, Retaining Walls, and Closure Structures for geotechnical requirements as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge;
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices;
 the structural works are designed in accordance with sound engineering practices to provide protection from the 200-year ULDC event; and
 the structural works are in place and functioning as intended for the 200-year ULDC event.

Rebecca L. Money, PE, GE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
_____________________________________________9/11/2024______ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.15: ANIMAL BURROWS
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following documents form the basis of this opinion.  SAFCA American River North Levee System; Levee O&M Review in Support of FEMA and ULDC Certification, prepared by MBK Engineers, dated February 22, 2024.  Rodent Control & Abatement Program, prepared by American River Flood Control District, dated October 2017.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumed the levees will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.15 Animal Burrows as described in the above referenced documents;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
___________________________________________________02/22/2024_____ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.16: LEVEE VEGETATION
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following documents form the basis of this opinion.  SAFCA American River North Levee System; Levee O&M Review in Support of FEMA and ULDC Certification, prepared by MBK Engineers, dated February 22, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.16 Levee Vegetation as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
__________________________________________________2/22/2024 Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.17: WIND SETUP AND WAVE RUNUP
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following documents form the basis of this opinion.  American River North Levee System Due Diligence Review for ULDC & FEMA Certification; Appendix D; ANLS Wind Setup and Wave Runup Analysis, prepared by Mead & Hunt, dated Sept. 13, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.17 Wind Setup and Wave Runup as described in the above-referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Stephen R. Sullivan, PE
Mead & Hunt
180 Promenade Circle, Suite 240
Sacramento, CA 95834
___________________________________________________________________ Signature Date
Not Valid Unless Stamped
September 13, 2024
ENGINEER’S OPINION
ULDC 7.18: SECURITY
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following document forms the basis of this opinion.  American River Flood Control District, Security Plan – American River North Levee System, dated March 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.18 Security as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
___________________________________________________4/3/2024____ Signature Date Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.19: SEA LEVEL RISE
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or evaluated in the following documents form the basis of this opinion.  American River North Levee System – Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee, prepared by MBK Engineers, dated July 1, 2024.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.19 Sea Level Rise as described in the above referenced document;
 data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Don Trieu, PE
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
_______________________________________________7/1/2024 Signature Date
Not Valid Unless Stamped
ENGINEER’S OPINION
ULDC 7.20: EMERGENCY ACTIONS AND FLOOD SAFETY PLANS
This opinion is made to assist the Sacramento Area Flood Control Agency (SAFCA) in complying with the requirements, definitions, and descriptions in the California Department of Water Resources’ (DWR) Urban Levee Design Criteria (ULDC) (May 2012) and to support SAFCA’s certification of the Urban Levee System of:

AMERICAN RIVER NORTH LEVEE
All information, calculations, definitions, descriptions, restrictions, limitations, or other pertinent data contained in or referenced in the following document forms the basis of this opinion.  American River Flood Control District Flood Safety Plan, as required by California Water Code 9650, January 2018.

LIMITATIONS OF ENGINEER’S OPINION
Consistent with current practice, this opinion of expected flood control system performance is valid for 20 years from the date of the SAFCA certification and assumes the levee will be properly maintained during the certification period.

This opinion by a registered professional engineer does not constitute a warranty or guarantee of performance, express or implied.

It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

The use of the term certification in this document is based on the following:

Per California Business And Professions Code, Division 3, Chapter 7, Article 3, 6735.5. The use of the word “certify” or “certification” by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of the certification, and does not constitute a warranty or guarantee, either expressed or implied.

OPINION
This Engineer’s Opinion attests that:
 the subject levee system meets the requirements of the ULDC for Section 7.20 Emergency Actions and Flood Safety Plans as described in the above referenced document;  data used in the evaluations and analyses supporting this opinion are accurate to the best of my knowledge; and
 the analyses have been performed in accordance with DWR’s ULDC and/or sound engineering practices.

Tom Engler, PE, CFM
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825-6579
________________________________________________04/03/2014____ Signature Date
Not Valid Unless Stamped
Appendix B.

American River North ULDC
Independent Panel of Experts
Report and Comment Closeout
August 29, 2024
Mr. Tom Engler, PE
MBK Engineers
455 University Ave, Suite 100
Sacramento, CA 95825
Dear Mr. Engler:

Subject: Sacramento Area Flood Control Agency (SAFCA)
Urban Level of Flood Protection Engineer’s Report for the American River North Levee System
Independent Panel of Experts’ Concurrence with Engineers’ Report At your request, the Independent Panel of Experts (IPE) (Dr. David Williams, P.E., PH, CFM, BC.WRE, Mr. Michael Hughes, PE, and Mr. Darren Mack, PE, GE) has conducted an independent quality assurance review of the Sacramento Area Flood Control Agency’s (SAFCA) Urban Level of Flood Protection (ULOP) Engineers’ Report for SAFCA’s American River North Levee System. The American River North Levee System consists of American River North Levee, Natomas East Main Drainage Canal East Levee, and Arcade Creek South Levee.

The Engineers Report and its supporting documents are intended to provide substantial evidence that the American River North Levee System meets the Department of Water Resources’ (DWR’s) ULOP Criteria for a 200-year flood event (1-in-200 annual chance of exceedance) in accordance with the DWRs’ Urban Levee Design Criteria (ULDC) issued in May 2012.

IPE Charge and Scope of Work
The IPE has been tasked to provide independent, expert opinion regarding SAFCA’s certification.

Tasks include, but are not limited to, the following:
• Preparation and attendance of IPE meetings;
• Review and comment on Due Diligence reports supporting ULOP certifications; •
• Review and comment on the Engineer’s Reports supporting the certifications; and • Preparation of IPE’s report documenting opinion on whether the flood system meets ULOP certification standards.

Materials provided to the IPE for review included the draft Engineers’ Report for the American River North Levee System, dated February 2024 (revised July 2024), and the following supporting documents:
• Appendix C: DRAFT American River North Levee System - Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee, MBK Engineers, February 09, 2024, revised July 1, 2024. • Appendix D: DRAFT North Area Streams ULDC Geotechnical Findings For NEMDC East Levee Stations 3029+00 to 3051+00 And Arcade Creek South Levee Stations 4000+00 to 4110+00, AECOM, March 15, 2024, revised July 22, 2024.
• Appendix E: DRAFT ULDC GEOTECHNICAL FINDING – AMERICAN RIVER NORTH LEVEE (STATION 3000+00 TO 3051+00) AND NEMDC EAST LEVEE STATION (3001+50 TO 3029+00), SACRAMENTO AREA FLOOD CONTROL AGENCY, SACRAMENTO COUNTY, CALIFORNIA, Kleinfelder Inc., February 16, 2024, revised July 23, 2024.
• Appendix F: DRAFT Geotechnical Due Diligence Report – Urban Levee Design Criteria American River North Basin, American River North Levee Station 3051+00 to 3548+50 and NEMDEC East Levee Station 2986+00 ti 3001+50, SAFCA FEMA and ULDC Evaluation, Sacramento County, CA, MBK Engineers, February 02, 2024, revised June 28, 2024. • Appendix I: AMERICAN NORTH LEVEE SYSTEM Due Diligence Review for ULDC & FEMA Certification – Draft, Mead & Hunt, April 26, 2024, revised July 24, 2024. • Appendix J6: Penetrations Exceptions Work Plan, American North Levee System (ANLS), SAFCA Due Diligence Review for Urban levee Design Criteria Section 7.13, July 24, 2024.

Other information was provided for context.

DWR Urban Level of Flood Protection Criterion EVD-1:

Section 2.0 of the ULOP provides the following criterion that is considered by DWR to be necessary for reasonable and responsible decision making.

EVD-1: Substantial evidence in the record to support a finding related to an urban level of flood protection based on flood management facilities providing the required level of flood protection shall include the following, at a minimum:
• A report prepared by a Professional Civil Engineer registered in California to document the data and analyses for demonstrating that the property, development project, or subdivision has an urban level of flood protection.
• A report by an Independent Panel of Experts on the review of the report prepared by the Professional Civil Engineer.
• A response by the Professional Civil Engineer to the comments from the Independent Panel of Experts.
• Any additional data and information that cities or counties use to make the finding.

DWR’s ULDC document presents mainly procedural criteria associated with making a finding consistent with legislative requirements. DWR considers that an urban level of flood protection could be achieved by structural and nonstructural means, or a combination of both. Therefore, DWR’s ULDC, as described below, are incorporated by reference in the ULOP Criteria.

DWR’s ULDC document provides the engineering criteria and guidance for the design, evaluation, operation, and maintenance of levees and floodwalls that provide a 200-year ULOP and outlines 20 technical areas associated with levee integrity and the evaluations needed for compliance, these being:
• Section 7.1 - Design Water Surface Elevation
• Section 7.2 - Minimum Top of Levee
• Section 7.3 - Soil Sampling, Testing, and Logging
• Section 7.4 - Slope Stability for Intermittently Loaded Levees • Section 7.5 - Underseepage for Intermittently Loaded Levees • Section 7.6 - Frequently Loaded Levees
• Section 7.7 - Seismic Vulnerability
• Section 7.8 - Levee Geometry
• Section 7.9 - Interfaces and Transitions
• Section 7.10 - Erosion
• Section 7.11 - Right-of-Way
• Section 7.12 - Encroachments
• Section 7.13 - Penetrations
• Section 7.14 - Floodwalls, Retaining Walls, and Closure Structures • Section 7.15 - Animal Burrows
• Section 7.16 - Levee Vegetation
• Section 7.17 - Wind Setup and Wave Runup
• Section 7.18 - Security
• Section 7.19 - Sea Level Rise
• Section 7.20 - Emergency Actions
The above listed sections were referenced during the IPE review to verify that the completed levee system certification meets the ULDC and standards.

Independent Panel of Experts Review and Findings
The IPE reviewed the Engineer’s Report and supporting documents (Appendix C, D, E, F, I, and J6), attended meetings with the certification team, visited the levee site, and provided review comments and “backcheck” replies to Engineer’s team responses. A spreadsheet that documents the IPE comments, Engineer’s team responses, and comment closures is attached to this letter. Changes, clarifications, and improvements to the Engineer’s Report, and supporting documents, were made where needed.

Based on its review, the IPE provides the following findings:
• The certification team, in our opinion, had followed the standards of engineering required for certifying the levees included in the American River North Levee System. • Adequate and appropriate information1 has been gathered and presented to the IPE to perform the review needed to support the certification package. • The engineering documentation provided were appropriate to accurately provide compliance with the ULDC to address the technical areas listed above. • The references cited in the Engineer’s Report (including the Due Diligence and Engineer’s Opinions reports), provide the appropriate and adequate information to support those Opinions.
• Exceptions to ULDC criteria requested by the certification team are reasonable and adequately supported.
• In the IPE’s judgment, the documentation, evaluations, and management approaches were completed in accordance with sound engineering practices2to provide protection up to the 200-year flood event, and support ULOP and ULDC certification of the American River North Levee System.

The Engineer’s Report is a requirement for SAFCA to obtain ULOP Certification for a levee system.

The ULOP Criteria, Sub-Section EVD-1, requires a report by the IPE documenting its review of the Engineer’s Report and its supporting documents. This letter and its attachment serve as documentation of the IPE’s review and concurrence that the completed levee system provides the required Urban Level of Flood Protection.

Respectfully submitted,
Sacramento Area Levee Certification Project
Independent Panel of Experts
_____________________________ ____________________________ Michael Hughes, P.E. Darren Mack, P.E., G.E.

Independent Expert Panel Member Independent Expert Panel Member _______________________________________
Dr. David T. Williams, P.E., PH, CFM, BC.WRE
Independent Expert Panel Member
1 Assessment of adequacy and appropriateness for geotechnical issues along the American River North Levee relies heavily on the Statement of Performance provided by US Army Corps of Engineers. 2 It is assumed that “sound engineering practices” are practices that are performed in a manner consistent with the degree of skill and care ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions.

RE
No. DOCUMENT LOCATION IN DOCUMENT

IPE'S COMMENT
(06/21/2024)

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(08/28/2024)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
1 Urban Level of Flood Protection Engineer's Report for the American River North Levee System, February 2023
Cover page Report date on front page is not consistent with date of April 2024 show in the Certification Statement of the report. Make consistent in future revisions Date revised (RLM 6/27/24) accepted - closed 2 Introduction - Limits and Conditions of This Certification "any particular levee system" should be "any particular portion of the levee system" Text revised (RLM 6/27/24) accepted - closed 3 Introduction - Limits and Conditions of This Certification, 1st bullet it states "Integrity of the levee system has degraded to the point that the identified improvements will not be adequate to provide an urban level of flood protection,," What about degradation of portions not improved?
No change to text, bullet #2 covers this topic (RLM 6/27/24) accepted - closed 4 Introduction - Limits and Conditions of This Certification, 1st bullet "1-in-200 chance of annual flood" Do not need "of" No change to text, preference is to keep "of" in the phrase (RLM 6/27/24) accepted - closed 5 Table of Contents Page numbers are missing in the in the main text and need to be added. Page numbers added (RLM 6/27/24) accepted - closed6 Table of Contents, section 2 and 3 American River North should be capitalized Headings in Table of Contents were fixed (RLM 6/27/24) accepted - closed 7 Acronyms and Abbreviations list
Some of the acronyms shown here are only used in the report once or twice and as such are not needed. Other acronyms are shown in the report text, but not shown here (e.g. ALERT and USGS). Suggest reviewing and revising the list.

Abbreviations were spelled out and accronyms were checked and the list updated (RLM 6/27/24) accepted - closed
8 Section 1.0, second paragraph
First sentence is not clear to a reader not familiar with the levee system. Suggest presenting here specifics of the levees included in the American River North Levee System
Text revised to include levee segments (RLM 6/27/24) accepted - closed 9 Section 1.0, fifth paragraph Delete the struck word 'some' from the text Text revised (RLM 6/27/24) accepted - closed 10 Section 1.0, last two paragraph paragraph
First paragraph at the top of the page states that "the structural flood control facilities protecting the urban area of the City from flooding would be able to withstand flooding from a 1-in-200 year AEP flood event". The last paragraph then states "Since the American River North Levee System does not require structural improvements, and non-structural actions have been completed................." Are these two statements contradictory? Also, it is recommended defining in a footnote what structural and nonstructural repairs are.

Text has been revised to be more clear on the status of the system (RLM 7/9/24) accepted - closed
11 Section 2, 1st para Should state that left and right is looking downstream Text revised to define left and right (RLM 6/27/24) accepted - closed 12 Section 2.0, Physical Description Arcade
Creek South, third paragraph.

Can it be stated that there would be no waterside development in the future? Also, on the landside, no additional infrstructure adjacent to the levee, such as pools will not be allowed to be placed per local regulations?
Text revised (RLM 6/27/24) accepted - closed
13 Section 2.0, Physical Description Arcade Creek South, second paragraph. Select crest or crown to describe the top of levee an keep it consistent throughout the report. Text revised (RLM 6/27/24) accepted - closed 14 Section 2.0, Physical Description Arcade
Creek South, third paragraph.

Suburban development adjacent to the landside to the slope - this presents a challenge to flood fighting. Is this addressed in the report anywhere? This is discussed in the Right of Way section and also O&M (RLM 6/27/24) accepted - closed
15 Section 2, Physical Description, ACSL, 3rd paragraph Please clarify the sentence, "In 2019 a seepage cutoff wall was constructed along this stretch of levee along with modifications to pump stations, penetrations to be in compliance with ULDC and other requirements." Words seem to be missing. Also, "penetrations to be in compliance" suggests they are either not complete or were not in compliance.

Text revised (RLM 6/27/24) accepted - closed
16 Section 2.0, Physical Description Arcade
Creek South, third paragraph,
penultimate paragraph.

Should this sentence read “modifications to pump stations and penetrations in compliance with ULDC and other requirements? Text revised (RLM 6/27/24) accepted - closed 17 Section 2.0, Physical Description
Natomas East Main Drainage Canal,
second paragraph.

Figure 1 shows 3051+40 and not 3051+61 shown in the text? Please make consistent. Figure and/or text were revised to be consistent (RLM 6/27/24) accepted - closed 18 Section 2.0, Physical Description American River North, last paragraph. I think it is important to note that numerous swimming pools have been built in this section of levee. These presence of swimming pools needs to have been address by the associated geotechnical reports.

The geotechnical engineers have evaluated the pools, where applicable. If applicable a discussion is included in their respective reports. Reference to pools was added to Section 3.0 of the Engineers Report. No pools are located along NEMDC, one pool is located along Arcade South, and multiple pools are located along American River North. (RLM 6/27/24)
accepted - closed
19 Section 2.0, Physical Description
American River North, second
paragraph.

I am confused and need more explanation. The beginning of the paragraph states that construction was completed prior to ULDC. It then goes on to state “upon completion of features being proposed”.

Text revised (RLM 6/27/24) accepted - closed (Check revised text. 'is' should be 'are' or 'levees' should be 'levee') 20 Section 2.0, Physical Description
American River North, fourth
paragraph, sixth line.

What does “n.d.” stand for in the reference (USACE, n.d.)? Text revised (RLM 6/27/24) accepted - closed 21 Section 2.0, Physical Description American River North, fourth paragraph, sixth to ninth lines.

What defines the extents of the Lower American River levees and how do they relate to the ARNL system being studies? This should bb addressed in the text.A release of 115,000cfs is equivalent to a 200 year DWSE and therefore does not exceed the required DWSE.

Text revised (RLM 6/27/24) accepted - closed
22 Section 2.0, Physical Description
American River North, fourth
paragraph, eight line.

DWSE needs to be defined before use of acronym Text revised (RLM 6/27/24) accepted - closed 23 Section 2.0, Performance History, first sentence of first paragraph. Why isn’t there a sub-heading giving a write up of perfromance history for Natomas East Main Drainage Canal East Levee? Heading updated (RLM 6/27/24) accepted - closed 24 Section 2.0, Performance History, first sentence of first paragraph. It would be useful to the reader to state the wse during these flood events relative to the 200-year DSWE so that performance can be calibrated. Some of the gages are upstream and the elevations are not similar, which will cause more confusion. We have provided a sentence indicating flows have been below the 200-year DWSE. (RLM 6/27/24) accepted - closed 25 Section 2. Performance History, firs
para.

The first sentance says "No past performance issues have been reported.." and the next sentence says " Past performance issues include .." Contradictory Text revised (RLM 6/27/24) accepted - closed

SAFCA CERTIFICATION
American River North Basin
ULDC_AmNorthLevee_IPE_06272024_ResponsesBackCheck_08292024 1 of 3 No. DOCUMENT LOCATION IN DOCUMENT

IPE'S COMMENT
(06/21/2024)

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(08/28/2024)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
26 Section 2, Performance History
This section appears to separate performance into geotechnical performance (seepage, stability) and hydraulic (stage). For clarity, suggest adding a header for NEMDC (not currently included) and provide a summary of geotechnincal and hydrauliic past performance for each element separately, under the header, similar to the prior section.

Writeup for NEMDC added. Section numbering updated, this is now Section 4.0 (RLM 7/9/24)
Seepage and stability are covered under a blanket statement, and there are now three separate sections discussing stage. Accepted - closed.
27 Section 2.0, Performance History,
second paragraph.

If we are certifying the levee system, why are we using the term ‘largely mitigated’? This implies there are section that are yet to be mitigated Text revised (RLM 6/27/24) accepted - closed 28 Section 2.0, Performance History,
Arcade Creek South Levee, first
sentence of first paragraph.

USGS and ALERT need to be defined and added to the Acronyms section Text revised (RLM 6/27/24) accepted - closed 29 Section 2.0, Performance History,
Arcade Creek South Levee,first
paragraph, fourth line.

Is the difference in datums really 49.19 feet?
Yes, +49.19 feet is the conversion used by Sacramento County to convert the USGS reported gage height to NAVD88 elevation. (MA 7/1/240
accepted - closed
30 Section 2.0, Performance History,
American River North Levee,first
paragraph.

Figure 1 should be corrected to Figuire 2. There is not a figure 2. The text has remained the same (RLM/6/28/24) accepted - closed 31 ULDC 7.1, Design Water Surface Elevation, first paragraph Acronym DWSE used earlier in text without definition. Text needs editing for consistency. Text revised (RLM 6/27/24) accepted - closed 32 ULDC 7.1, Design Water Surface Elevation, second paragraph Should the reference be "(MBK, 2024a)"? Check rest of report for consistency. Reference revised (RLM 6/27/24) accepted - closed 33 ULDC 7.2, Minimum Top of Levee, first paragraph Mead & Hunt 2024a or 2024b? Please check and revise accordingly. Reference revised (RLM 6/27/24) accepted - closed34 ULDC 7.3, Soil Sampling, Testing and Logging.

General comment - it is noted that an exception is based in part by reliance of information from full time trench logging of cutoff walls Was the quality and findings of the historic trench logging verified at all as part of the due diligence reports by AECOM, Kleinfelder and MBK?
Yes, the trench logging was reviewed and where applicable, this discussion has been added to Appendices D, E, and/or F (RLM 7/25/24) accepted - closed 35 ULDC 7.3, Arcade Creek South and other sections of the system Just mentioning the AECOM study or description for the other segments do not explicitly say why the exception is justified - sample spacing?. Number of samples? Did the AECOM report say it was confident that the area was covered adequately, etc.? For instance, the last sentence for ANLS says "As such, this review indicates that sufficient documentation exists to meet this ULDC requirement through exception." Perhaps say this for all segments.

Text revised (RLM 6/27/24) accepted - closed
36 ULDC 7.3, Soil Sampling, Testing and
Logging, NEMDCEL.

General comment - Figure 1 shows extent of NEMDCEL from 2986+49 through to Station 3051+40. Text does not exactly match these limits. Please check all station limits for accuracy and make sure text and figures are consistent throughout the report.

All reports have been revised to reflect consistent station limits (RLM/6/28/24) accepted - closed
37 ULDC 7.4, Slope Stability for Intermittently Loaded Levees Please check with consultants to make sure the presence of swimming pools was accounted for in selection of critical cross sections for analysis. Same comment applies to Section 7.5 Underseepage The geotechnical engineers have evaluated the pools, where applicable. If applicable a discussion is included in their respective reports in Appendices D, E, and/or F. Analyses were reviewed for inclusion of pools or evaluated quantitatively to estimate how a pool may impact the seepage analysis results. Conclusions are provided in the supporting documentation in the Appendices D, E, and F. (RLM 7/9/24)
accepted - closed
38 ULDC 7.4, Slope Stability for
Intermittently Loaded Levees, Arcade
Creek South, 6th line.

Suggest adding ‘based on a’ to the sentence, as in ‘based on a review of’. This comment also applies to the write up 7.5 Underseepage, ARCSL. Text revised (RLM 6/27/24) accepted - closed 39 ULDC 7.4 Slope Stability, ARNL, 1st partgraph Correct STA 3051 to 3051+00 Text revised (RLM 6/27/24) accepted - closed 40 ULDC 7.4, Slope Stability for
Intermittently Loaded Levees,
NEMDCEL, 3rd line.

Figure 1 shows extent of NEMDCEL through to Station 3051+40. Please check all station limits for accuracy. Text and Figure revised accordingly (RLM 6/27/24) accepted - closed 41 ULDC 7.4, Slope Stability for Intermittently Loaded Levees, NEMDCEL, 10th line.

This sentence confuses me as written. I suggest restructuring slightly by deleting the end statement “, the results of which met criteria” and move to the beginning of the sentence as shown in the text.Same applies to American River North Levee write up below and in Section 7.5 Underseepage (both study areas).

Text revised (RLM 6/27/24) accepted - closed
42 ULDC 7.4, Slope Stability for Intermittently Loaded Levees, NEMDCEL, 12th line Suggest revising text to state “which covers the section of levee from Station 2986+50 to 3001+50 and a majority of the levee segments……”. Assuming this is factually correct. This comment applies to other similar sections of the reportRegarding the use of the word ‘majority’, does this mean there are sections of levee that are not covered by analysis by others, or the Statement of Performance provided by the Corps?
Text revised (RLM 6/27/24) accepted - closed
43 ULDC 7.5, Undedrseepage for
Intermittently Loaded Levees, 2nd
paragraph
Should information be presented to outline FOS requirements for the HTOL? Text revised (RLM 6/27/24) accepted - closed 44 ULDC 7.6, Frequently Loaded Levee ‘wse’ acronym previously introduced Text revised (RLM 6/27/24) accepted - closed 45 ULDC 7.7 Seismic Vulnerability
This section notes that a Post Earthquake Remediation Plan (PERP) is required for a segment of the ARNL to meeting ULDC certification criteria due to the high seismic vulnerability (Appendix E, Kleinfelder). Cursory review of the plan provided (Appendix J1) indicates this plan is draft/incolente, with coordination required between Kleinfelder and MBK. When is this report expected to be completed to support certificaion? The full document will be complete for review during comment response backcheck (RLM 6/27/24)
Appendix J1 does not appear to have been provided for review.

Comment remains open.

Appendix J1 and the Post Earthquake Remediation Plan have been provided to fulfill Comment 45 (5 files).

Based on Updates to the PERC, Comments 1 and 2 on
Supporting Document Appendix J1 have been resolved.

Accepted - closed
46 ULDC 7.8 Heading of LDC should be ULDC Text revised (RLM 6/27/24) accepted - closed 47 ULDC 7.8, Arcade Creek and NEMDC Should state who determine these to be minor streams and what criteria was used to determine it The last sentence in paragraph 1 describes the requested information. No change to the text was made (RLM 6/27/24) accepted - closed ULDC_AmNorthLevee_IPE_06272024_ResponsesBackCheck_08292024 2 of 3 No. DOCUMENT LOCATION IN DOCUMENT

IPE'S COMMENT
(06/21/2024)

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(08/28/2024)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
48 ULDC 7,8, Arcade Creek and NEMDCEL
These sections states that levee cross sections are included in Appendix D of the AECOM report. However, the AECOM report does not have an Appendix D, and it does not have a corresponding section ULDC 7.8. Suggest referencing Appendix E of the MBK report instead (Arcade Creek), which includes cross sections for all levee segments. Alternatively, add ULDC 7,8 to the AECOM report and include the cross sections in the AECOM report for consistency/completeness.

AECOM has added the Psomas figures to their report. The text has been revised to clarify that the cross sections are not in Appendix D of AECOM's report, but in the AECOM report included as Appendix D. (RLM 6/27/24)
This change does not appear to have been made to Section 7.8 of the Engineer's report The text still states the appendices are in Appenix D of the AECOM report, and there are no track changes in the section.

However, the sections were added to the AECOM report as Appendix D. Please confirm intent of response.

Comment remains open.

Revised Engineer’s Report text provided to clarify Comment 48 (1 word file). Accepted- Closed.
49 ULDC 7.9, ACSL
Items #4 and #5 state, "This structure was reviewed and meets the geotechnical requirements of this criteria." Suggest a similar statement be added for each structure. This would apply to all transitions and all levee segments.

Text revised (RLM 6/27/24) accepted - closed
50 ULDC 7.9, ACSL
Items #6 describes the issue but not the conclusion. Suggest describing that offset and overlap between the two walls was determined to be acceptable based on twodimensional seepage evaluation. Text revised (RLM 6/27/24) accepted - closed 51 ULDC 7.9, NEMDCEL
Item #3 in Appendix F (MBK), ULDC 7.9, NEMDC STA 3051+00, with a 100 foot overlap in the seepage cutoff wall, does not appear to be included in the list and should be added.

This is for American River north levee, the project was called NEMDC north. It is in the ARNL section. accepted - closed
52 ULDC 7.9, NEMDCEL
Items #4 and #5 (ditch and pumping plant, respectively) both state no past performance issues have been observed. However, Kleinfelder also noted that seepage and stability analysis had been reviewed. We stuggest adding that information so this isn't relying comply on observations. Similarly, Item #7 (telecom vault) does not mention concrete-encased conduits or crest cut off trench which are key components of the certification.

Text was revised to reference meeting geotechnical requirements (RLM 6/27/24)
Although the detail suggested wasn't provided, the intent of the comment was met with the text that was added. Accepted - closed. 53 ULDC 7.10 General for all segments
There are not indications where the cited flow velocities come from. I suspect from the MBK hydraulic models - is so they need to be cited and in the references. Also, for the ANLS, should cite the wind/wave report if waves are not an erosion mechanism.

Text revised to reference MBK reports (RLM 6/27/24) accepted - closed 54 ULDC 7.10, ACLS
The section states there are no major constructions in the channel. However, there are stretches with significant, large woody vegetation, homeless encampments and wood platforms, etc., within the narrow channel. Do any of these items have the potential to contribute to localized erosion during a storm event? Text revised (RLM 6/27/24) accepted - closed
55 ULDC 7.11, General This sections references the Right of Way plan as being in both Appendix H and J, and should be conformed. The Right of Way plan was not available for review. Text revised to reference both Appendix H and J (RLM 6/27/24) Appendix references have been clarified, although Appendix H and J have not been provided for review. Accepted- Closed. 56 ULDC 7.12, Encroachments General clean up of this section is required. The section refernces Appendix G as Mead & Hunt (2024) rather than the inspection by MBK (2024); the M&H report is in Appendix I; and the summary maps and tables are in Appendix H1 and H2. Also, it seems that this section should briefly discuss that for large portions if ACSL and ARNL development extends to the levee toe, which is why there is such a large number of encroachments.

Text revised (RLM 6/27/24) accepted - closed
57 ULDC 7.13, Penetrations
The appendix labels should also be corrected in Section 7.13 (and subsequent sections).Also, the section states that a penetration plan is required for ULDC compliance for the 240 penetrations identified. The plan is buried in a subappendix to Appendix I and is easy to overlook. We suggest MBK consider adding this “Penetration Exception Work Plan Technical Memorandum” to “Appendix J – Plans” so that it can be referenced with the other required compliance plans.

Text revised and we agree the plan will also be included in Appendix J (RLM 6/28/24)
Appendix J6 was provided for review.Time frames for implementation of the work plan have been added, which the IPE is in concurrence with. Accepted - closed.
58 ULDC 7.14, Floodwalls, Retaining Walls, and Closure Structures, ACSL, fourth paragraph What are the retaining walls use for? Same comment applies where this comment is used elsewhere.

The text states retaining walls are located at bridge structures and then are discussed in Mead & Hunt's report. Changes to text were made to provide more information on retaining wall systems. (RLM 6/27/24 and Sullivan 7/20/24)
accepted - closed
59 ULDC 7.14, Floodwalls, Retaining Walls,
and Closure Structures, ACSL, fourth
paragraph
Will be discussed or are discussed? Also, 7.13 is very general and doesn’t specifically mention retaining walls. Same comment applies where this comment is used elsewhere.

Text revised to better describe the retaining walls and point to Mead & Hunt's report (RLM 6/27/24) accepted - closed
60 ULDC 7.17, 1st para Perhaps explcitly state that if the wind set up and wave runup is 3 feet or less, it meets the 7.17 criteria. The criteria is not the result it is simply completing the analysis. The results are used in the MTOL determination (MA 6/27/24) Slight modification to the text made (Sullivan 7/20/24) accepted - closed ULDC_AmNorthLevee_IPE_06272024_ResponsesBackCheck_08292024 3 of 3 No. DOCUMENT LOCATION IN

DOCUMENT

IPE'S COMMENT
(06/21/2024)
Significance
Rating

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(8/28/24)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
1 Appendix C, MBK H&H Report of Feb 9,
2024 Figure 1
Should state that the solid yellow line is the levee being studied and the dotted yellow line is a levee that is not part of the study, either in section2 or in the figure.

A legend has been added to Figure 1 to define the line types. (MA 7/2/24) accepted - closed 2 section 3.1, 1st para Did MBK create the LAR hydraulic model or was it adapted from another one? The model was adapted from the CVFED Sacramento River watershed model. This info, and reference, has been added to report in new Section 4.1. (MA 7/2/24) accepted - closed 3 section 3.1, 2nd para Figure 2 shoulf be reference in this paragraph Disagree. The 1st paragraph is the appropriate location for Figure 2 reference in new Section 4.2. (MA 7/2/24) accepted - closed4 section 3.2, 1st para Should the cited Figure 2 be actually Figure 3 and the Figure 2 schematic be actually Figure 3? Figure numbering has been corrected in new Section 4.2. (MA 7/2/24) accepted - closed5 page 5 Figure 3 and 4 should actually be Figure 4 and 5, respectively Figure numbering has been corrected. (MA 7/2/24) accepted - closed6 page 6 Figure 5 should be Figure 6 Figure numbering has been corrected. (MA 7/2/24) accepted - closed7 section 3.3 Please expand why the weir widening project used the 1986 pattern and not the 1995 pattern The report, new Section 4.3, was modified to better describe the need for the two Sacramento River system models. To facilitate this description, the Hydrology section was moved to Section 3 in front of the Hydraulic Models section, new Section 4. (MA 7/2/24) accepted - closed
8 Table 4
For Fair Oaks-latitude of Sacramento, expound on why the the 200 year is 1986 event scaled to 110% but the 500 year is the 1986 event (same event) but scaled to only 100% in the context of selection by I cannot expound on this. The CVHS event selection was done by USACE. (MA 7/2/24) accepted - closed 9 section 5.2, beginning of
2nd para Cite Appendix C for the letter and add reference to reference section Comment noted, no change made. With the letter included in Appendix C, including a reference in the reference section is unnecessary. (MA 7/2/24) accepted - closed
10 Figure B-3 in Suspect bubble, should say"see Table B-2, Dry Creek East Branch at Elkhorn Blvd." Reference to Table B-2 was added to Figure B-3. (MA 7/2/24) accepted - closed 11 Table D-1 and others Suggest defining SVRP again in title of table A list of profile acronyms was added to the Appendix D title page. (MA 7/2/24) accepted - closed12 General Suggest a section on abbreviations/acronyms An acronyms and abbreviations section has been added. (MA 7/2/24) accepted - closed 1 Appendix D: North Area Streams ULDC
Geotechnical Findings for NEMDC East Levee Stations 3029+00 to 3051+00 and Arcade Creek South Levee Stations 4000+00 to 4110+00, AECOM March 15, 2024.

1.0 Introduction, first
paragraph, second line
and Table 2-1
Station limits for NEMDC and ACSL are not complete on Figure 1 (e.g. NEMDC missing downstream end (3029+00) and reach stationing (3034+00) and ACSL missing upstream end and reach stationing).

Station limits for each reach are provided in the table on Figure 1. However, reach limit station have been added to the plan on the figure. (Barnes 7/23/24) accepted - closed
2 1.0 Introduction, second
paragraph, first bullet
End Station of 3051+00 is shown, byt Figure 1 of MBK's Engineers Report shows3051+40. Assess which is correct and update accordingly. Comment applies elsewhere throughout the report. 3051+00 is the historic end point referenced in the supporting documentation for the project as shown on Figure 1. 3051+40 is the station where the NEMDC and Arcade Creek south levee centerlines intersect. Changed to 3051+00 for consistency. (Barnes 7/23/24)
accepted - closed
3 1-1 North Area Streams
Background, Page 1-2,
first paragraph first line
SAFCA is missing the letter 'A' at the end. Text revised (Barnes 7/23/24) accepted - closed 4 Section 2.1.3, second
paragraph
There is no details in the reference of what section of levee the AECOM 2016 report referes to. The report reference appears incomplete.

Reference expanded as follows: AECOM, 2016. North Area
Streams Levee Improvement Project, Final Geotechnical Engineering Report for Project Design (GERPD) . (Barnes 7/23/24)
accepted - closed
5 Table 2-2 Fifth column, '2024 Survey Check Data' should read '2023 Survey Check Data' based on text.4 Corrected here, elsewhere in the text, and in Section 5 references (Barnes 7/23/24) accepted - closed 6 Section 2.1.7 Design
Water Surface Elevation
Text suggests that the DWSE was developed to include 1 foot of resiliency that takes into account climate change, whereas the Engineers Report states differently. Please make text consistent. 1-foot increase and resilience discussion removed. (Barnes 7/23/24) accepted - closed 7 Section 2.1.7 Design
Water Surface Elevation,
page 2-4, first
paragraph, second line.

Use of the phrase 'current geotechnical analyses' could imply analysis as part of AECOM's 2024 report, but I don’t think that is the case, and therefore the wording could be misleading. I believe the phrase is referencing previous analysis as part of the PIRs prepared in 2014/2015 ot the 2016 GERPD. IF this is the case consider refereencing these docuents for clarity. This comment applies to other locations where the same phrase has been used.

Deleted all places where it appears in connection with geotechnical analyses. (Barnes 7/23/24) accepted - closed 8 2.2.1 Subsurface
Investigations, page 2-6,
second paragraph, thrid
line
Text does not indicate the water surface elevation related to the hydraulic head. Presumably it is the DWSE, in which case this should be added to the text - e.g. 'where the DWSE htdraulic head on the levee'.

Added DWSE (Barnes 7/23/24) accepted - closed
9 2.2.1.1 Conclusions
Should this paragraph include reference to 'exceptions' as in strict accordance with ULDC 7.3, the frequency, location and number of explorations does not meet criteria.

Reference to exception to ULDC 7.3 is added. (Barnes 7/23/24) accepted - closed 10 2.2.1.1 Conclusions Text references SPK SOP (USACE, 2019). I think the latest addition is May 2022. Changed to APK SOP USACE 2022 (Barnes 7/23/24) accepted - closed 11 Table 2-5 Third row first column missing the word 'Slope' at the end. Text revised (Barnes 7/23/24) accepted - closed 12 2.3.1 Conclusions, sixth
line.

The sentence as written is incomplete. Suggest adding the words "based on a' in front of the word review. Comment applies elsewhere in the report where this statement has been used.

Changed to "..a review.." where appears in the text (Barnes 7/23/24) accepted - closed 13 Table 2-6, page 2-8 Second row, thrid column contains the number 1 by mistake. Text revised (Barnes 7/23/24) accepted - closed 14 Table 2-6, page 2-8 There are no numbers in the Table corresponding to notes 2 and 3 to inform the reader where the note is applicable. Text revised (Barnes 7/23/24) accepted - closed

SUPPORTING REPORTS

REVIEW BY INDEPENDENT PANEL OF EXPERTS (IPC)
1 No. DOCUMENT LOCATION IN

DOCUMENT

IPE'S COMMENT
(06/21/2024)
Significance
Rating

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(8/28/24)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
15 Section 2.4, page 2-8,
fourth paragraph Fifth line of text references Table 2-5, when I believe it sould be 2-6 Table 2-5 is correct, however, in first sentence, revised reference to Table 2-6 to specify allowable exit gradients for clarification. (Barnes 7/23/24) Table 2.5 references minimum ULDC FOS for Slope Stability. This doesn't appear correct in the context of the paragraph, which is discussing underseepage exit gradients. Comment remains open.

Report text updated to address comment. Accepted - closed 16 2.4.1, page 2-8 Same comment as above regarding insertion of 'based on a review'. Changed to "..a review.." wherever it appears (Barnes 7/23/24) accepted - closed17 Table 2-7, page 2-9 Sixth row, thrid column should be a Station range and not a specific station. Text revised (Barnes 7/23/24) accepted - closed 18 2.5.1 Toe Cutoff Wall
Interface - Station
3029+00, second
paragraph, second bullet
Typo - 'failure' should be 'fails' Text revised (Barnes 7/23/24) accepted - closed (this is now Section 2.7.1) 19 2.5.4 Slurry Cutoff Wall
Interface -ACSL Station
4031+18, third
paragraph, fourth line
Typo - sentence missing the word 'and' between 'issue, further' Text revised (Barnes 7/23/24) accepted - closed (this is now Section 2.7.4) 20 2.5.4 Slurry Cutoff Wall
Gap -ACSL Station
4068+45
Heading should state the station range of the gap and not a specific Station.

Section 2.5.5 chnged to add start and end stations (Barnes 7/23/24) accepted - closed
(this is now Section 2.7.4)
21 2.5.4 Slurry Cutoff Wall
Gap -ACSL Station
4068+46, page 2-13,
third paragraph, seventh
line
Typo - 'to meet" is repeated and needs to be deleted. Text revised (Barnes 7/23/24) accepted - closed (this is now Section 2.7.4) 22 Table 3-1 does the table need to indicate that ULDC 7.3 meets by exception? Added "By Exception" for both instances. (Barnes 7/23/24) accepted - closed 23 Appendix A
The updated ULDC water surface elevations are referenced as MBK 11/14/23. Appendix C (MBK H&H Report) is dated February 9, 2024.

Were there any meaninful changes to the water surface elevations Low Table header changed to 2024 (Barnes 7/23/24) accepted - closed 24 Appendix B
Table 8-1 contains one location (ST 4040+00) with breakbout above the levee toe with potentially erodible levee material (SM) and multiple other locations with likely less to non-erodible material (SC).

Not all locations have a cut off wall. Altuogh underseepage and through seepage criteria are satisfied, we suggest adding a brief description to the text as to why progressive erosion at the toe is not a concern from a certification standpoint.

Medium
To address this, Section 2.7 has been added to the report. It addresses potential breakout erosion on the landside levee slope. (Barnes 7/23/24) accepted - closed
(a period '.' is needed after 'evaluated' and before 'Since' in the fifth line of Section 2.8.1 NEMDC East Levee.
25 General
The AECOM report does not have a section discussing ULDC 7.7 Seismic Vulnerability. The Engineer's report states the materials were previously determined to be non-liquefiable. How was this determined? Should AECOM provide a section to support this statement.

High New Paragraph 2.5 has been inserted addressing ULDC Section 7.7, Seismic Vulnerability. (Barnes 7/23/24) accepted - closed Appendix D:Additional Comment
Section 2.0, Physical Description American River North, last paragraph.

I think it is important to note that numerous swimming pools have been built in this section of levee. These presence of swimming pools needs to have been address by the associated geotechnical reports.

The one pool along ACSL at Sta. 4060+00 has been described in new Section 1.2. The seepage evaluation for the pool has been added in new paragraph 2.4.1 and analysis results are added to appendix B. (Barnes 7/23/24) accepted - closed
Appendix D:Additional Comment
ULDC 7.3, Soil Sampling, Testing and Logging.

General comment - it is noted that an exception is based in part by reliance of information from full time trench logging of cutoff walls Was the quality  and findings of the historic trench logging verified at all as part of the due diligence reports by AECOM, Kleinfelder and MBK?
For AECOM, the only slurry cutof walls installed are those completed as part of the most remediation work for which the trench logging was perfromed by AECOM as described in Section 2.2.1. There are no historic loggs to review. (Barnes 7/23/24) accepted - closed
Appendix D:Additional Comment
ULDC 7.3, Arcade Creek
South and other sections
of the system
Just mentioning the AECOM study or description for the other segments do not explicitly say why the exception is justified - sample spacing?. Number of samples?  Did the AECOM report say it was confident that the area was covered adequately, etc.?  For instance, the last sentence for ANLS says "As such, this review indicates that sufficient documentation exists to meet this ULDC requirement through exception."  Perhaps say this for all segments.

Refer to the last sentence in 2.2.1.1 that has been modified to address the comment. (Barnes 7/23/24) accepted - closed Appendix D:Additional Comment
ULDC 7.4, Slope Stability
for Intermittently Loaded
Levees
Please check with consultants to make sure the presence of swimming pools was accounted for in selection of critical cross sections for analysis.

Same comment applies to Section 7.5 Underseepage
See response to Section 2 comment above (Barnes 7/23/24) accepted - closed 1 Appendix E: ULDC Geotechnical Findings -
American River North Levee Station 3000+00 to 3051+00 and NEMDC East Levee Station3001+50 to 3029+00, Kleinfelder, May 2024
Section 1.2.1, ARNL Station 3000+00 to
3051+00, page 2, 10th
and 11th lines
Qualify the datum being used for elevation at the start of the report.

Added Section 1.2 "Project Stationing and Datums" to define the project stationing and the elevation datum (Beswick 7/23/24) accepted - closed
(Table of Contents needs to be updated to reflected new section numbering)
2 Section 1.2.1, ARNL
Station 3000+00 to
3051+00, page 2, 7th
and 8th lines
Distance between statioing does not match for stated ranges - distance of 1310 feet for one and 1380 feet for the other (USACE).

The USACE stations and the corresponding ULE station have been reviewed and the ULE stations have been revised as needed (Beswick 7/23/24) accepted - closed
3 Section 1.2.2, NEMDCEL
Station 3001+50 to
3029+00, page 2, second
paragraph, third line
Typo - missing the word 'and' between '3 feet widening' Sentence revised to, "The improvements from Stations 3001+50 to 3029+00 included raising the crown elevation and an approximately 3-foot widening of the embankment toward the waterside." (Beswick 7/23/24)
accepted - closed
4 1.3 Methodolody, page
3, first para., second line Typo - missing the word 'in' between 'docemnted kleinfelder' Sentence revised to, "ARNL analyses were documented in the Kleinfelder 2009 Seepage and Slope Stability Report, ... " (Beswick 7/23/24) accepted - closed
5 1.3 Methodolody, page
3, third para., third line Should the sentence be referencing 'lowest' rather than 'highest WSE' The sentence is intended to make a blanket statement that the WSE previously analyzed is higher than the current/2024 WSE. Demonstrating that the analysis met with a higher WSE. (Beswick 7/23/24) Understood, but as written it still doesn't clarify whether the lowest WSE analyzed by KLF was above or below the 2023 HTOL WSE. This is why it is suggested to revise the sentence to" The 2023 HTOL WSE is lower than the lowest WSE analyzed in the above referenced reports", provided this is factually correct. Comments remains open.

Report text updated to address comment. Accepted closed 1 No. DOCUMENT LOCATION IN

DOCUMENT

IPE'S COMMENT
(06/21/2024)
Significance
Rating

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(8/28/24)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
6 2.1 ULDC Section 7.3 Soil
Sampling Testing and
Logging, page 11,
second para., last
sentence
Typo - sentence is incomplete as written.

The sentence was revised to, "The Geophysical HEM in the subject portion of the NEMDCEL, generally showed a moderate resistivity, which is typical of soils such as sandy silts and sandy clays. " (Beswick 7/23/24) accepted - closed
7 2.2 ULDC Sect5ion 7.4
Slope Stability, page 13,
second, para., fourth line.

I believe the word 'below' should be replaced with above. That is the previously perfromed analysis were completed using a WSE above the current WSE.

The sentence was revised to, "Since the previously performed analyses were analyzed with a WSE that is above the current 2023 200-year and HTOL WSEs …" (Beswick 7/23/24) accepted - closed
8 2.3 ULDC Sect5ion 7.5
Underseepage, page 17,
second paragraph,
fourth line
Same comment as above
The sentence was revised to, "Since the previously performed analyses were analyzed with a WSE that is above the current 2023 200-year and HTOL WSEs …" (Beswick 7/23/24) accepted - closed
9 2.5.1 Current Levee
Geometry, page 23, first
para., sixth line
Typo - 'selection' should be 'select'. The sentence was revised to, "Psomas performed surveys at select locations along ARNL and NEMDCEL. " (Beswick 7/23/24) accepted - closed 10 2.6.7 Transition Start of
ARNL Cutoff Wall, page
28, first para., first line
Typo - the word 'of' after 'tip' is not needed.

The sentence was revised to, "Kleinfelder reviewed the as-built drawings for the seepage cutoff wall that was installed to tip Elevation +5 feet…" (Beswick 7/23/24) accepted - closed
11 2.6.9 Interface of UPRR
Embankment on
NEMDCEL Landside
Slope, page 29, second
para., first line.

Is reference to 'seepage and slope stability analysis' accurate, because there is no mention of analysis in the preceeding paragraph? This comment applies to other sections of the report.

The paragraph above cites, "The UPRR embankment geometry was included in the seepage and stability analysis which met criteria." (Beswick 7/23/24)If the feature being assessed was included in one or more models then this statement was included. "seepage and stability analysis" was removed from Sections 2.6.5, 2.6.6,

2.6.11, and 2.6.12.
accepted - closed
12 2.7.4 Conclusions, page
33, second bullet. Typo - sentence mising the word 'stability' at the end.

Second bullet revised to, "•UPRR closure structure meet the geotechnical requirements of the ULDC for seepage and slope stability" (Beswick 7/23/24) accepted - closed
13 3.0 American River North
Levee Summary of
Results, page 34, first
paragraph.

Typo - sentence is incomplete as written. It seems 'it is' should be replaced with 'in'.

Sentence revised to, "Based on the review summarized in Section 2, above, Table 3.1 includes those reaches that in Kleinfelder’s opinion meet..." (Beswick 7/23/24) accepted - closed
1 Appendix F, Geotechnical Due Dilligence
Report - Urban Levee Design Criteria American River North Basin - Arcade Creek South Levee, NEMDC East Levee, and American River North Levee, MBK, Feb 2024
General Please add page numbers to the document. Page numbers added (RLM 6/26/24) accepted - closed 2 Report Title
The title of the report is confusing. First heading states three different stufy area, and the second heading indicates just ARNL and NEMDC. Is there a way of combining these headings so it is less confusing? For example - Geotechnical Due Diligence Report - Urban Levee Design Criteria for Americak River North Levee (Station 3051+00 to 3548+00 and NEMDC East Levee Station 2986+50 to 3001+50.

Title revised (RLM 6/26/24) accepted - closed
3 Background, first
paragraph, second
sentence, fourth and
fifth lines
Sentence states "ongoing efforst that are necessary to complete the remaining improvements in reducing flood risk". This needs further clarification to define what needs to be completed and by what time.

Projects needing completion were added (RLM 6/26/24) accepted - closed 4 Background, second
paragraph, first
sentence, third line.
the word 'respectively' isn't needed. Word removed (RLM 6/26/24) accepted - closed 5 Background Table 1.

ULDC Certification
Criteria
Item 7.14 Floodwalls, Retaining Wall, and Closure Structures is covered in the report and therefore should it be italicized based on the notes to the table.

Table revised (RLM 6/26/24) accepted - closed
6 Background Table 1.

ULDC Certification
Criteria, Footnote
Last sentence of footnote states "scope shall be perfromed by others". What is the status of these reviews? Footnote revised (RLM 6/26/24) accepted - closed 7 Background Table 2.

Additional
Documentationto
Support ULDC
Certification
Table 2 is not referenced in the report. Reference added to Table 2 in Background paragraph (RLM 6/26/24) accepted - closed 8 Background, second
page of document, Item
1, fourth line
Sentence appeasr incomplete. Should it read "parcel and placed a restriction"? Text revised (RLM 6/26/24) accepted - closed 9 Water Surface Elevations
and Datums, second
paragraph
Typo - reference needs a 'd' at the end. Reference revised (RLM 6/26/24) Comment referenced a typo for the word 'reference' in the second paragraph. Comment not critical.

Accepted - closed
10 UTDC 7.3, Second
paragraph, sixth line
Sentence states a'cursory review' was perfromed and then states 'that sufficient documentationexistis to meet this requirement through exception'. Given the nature of the work being done, i.e. certification, I don't think reviews should be cursory.

Text revised (RLM 6/26/24) accepted - closed
11 ULDC 7.4, fifth
paragraph
Paragraph states that analyses were not reviewed in detail and no review was perfromed to confirm that each reach was evaluated. A;so, the final sentence is somewhat vague. Why was a detailed evaluation not perfromed? This should be clearly stated in the report.Same comments apply to ULDC 7.5 Text revised (RLM 6/26/24) accepted - closed
12 ULDC 7.4, last
paragraph
Typo - the word 'configuration' before after the word 'levee' is not needed.

Same comments apply to ULDC 7.5
Text revised (RLM 6/26/24) accepted - closed
13 ULDC 7,.8 Levee
Geometry
Since Appendix D (AECOM) does not cover Levee Geometry, and Appendix E of this report includes surveyed cross sections for the entire project, for clarity we suggest this section be reivsed to provide evidence for the entire project, rather than the ARNL and NEMDCEL stations listed.

Low
Disagree, AECOM will add a statement in their report. The Engineer's Report will summarize all findings on Geometry (RLM 6/26/24) Response acceptable. Inclusions of cross sections in Appendix D of AECOM report has been confirmed. Closed.
1 No. DOCUMENT LOCATION IN

DOCUMENT

IPE'S COMMENT
(06/21/2024)
Significance
Rating

ENGINEER'S RESPONSE
(06/28/24)
IPE's COMMENT
(08/13/2024)

ENGINEER'S RESPONSE
(8/28/24)
IPE's FINAL COMMENT / CLOSURE
(08/29/2024)
14 ULDC 7.9
This section lists the reaches in paragraph form, but the transitions in numbered list form. This section would be easier to read, and to correlate to the Engineer's Report, if the stations, description, and evaluation were all group together, either in the list or in a table.

Medium Text revised (RLM 6/26/24) Accepted - closed.
15 Appendix D
Several different water surface elevations are refenced in this table, some of which are defined in the report. For clarity, it would be helpful to define these, either ina table in the text or a footnote to the table. That would provide context for the acceptability of the gradient and Factors of Safety provided. For example, I'm assuming EEWSE > HTOL, and therefore, the target factor of safety is 1.2.

High Notes were added to the table in Appendix D to clarify the WSE definitions (RLM 6/26/24) The complete report for Appendix F was not provided for review - only the updated text was provided. The tables from Appendix D, therefore, could not be backchecked. Comment still open. Complete report has now been provided Appendix F – 15 – Appendix D was provided for review and backcheck and all comments have been resolved. Accepted - closed 1 Appendix I - American River North Levee System Due Diligence Review for ULDC & FEMA Certification, Mead & Hunt, April 2024.

Main text No significant comments. Comment acknowledged accepted - closed 2 Appendix D, ANLS Wind Set-up and Wave Runup Analysis, Wind-Wave Analysis for American River North and RoblaArcade Levee Systems No significant comments are made for Appendix D. Comment acknowledged accepted - closed 1 Appendix J1 - Post-Earthquake
Remediation Plan, Kleinfelder, April 2024
Main Text and Appendix
A Comments added during backcheck process
Based on review of Appendix J1, there are several requirements of the PERP that do not clearly comply with the requirements of Section 7.7.1 of the ULDC. Up to 324,000 CY of fill volume is estimated, as a worst case, for interim levee repairs, which must be constructed within 8 weeks or less. There is no discussion of the feasibility of hauling and placing, at minimum, 6,000 CY/day of fill. This assumed all 8 weeks, 7 days a week, were avaialble for interim levee repairs, which is unlikely.

Appendix J1 and the revised Post Earthquake Remediation Plan provided for review.

J1-1 – SAFCA confirmed that annual on-call construction contracts are in place so that contractor resources can be mobilized quickly to meet the needs of the PERP.

Comment Resolved.

Aceepted - closed
2 Appendix J1 - Post-Earthquake
Remediation Plan, Kleinfelder, April 2025
Main Text and Appendix
A Comments added during backcheck process
Based on review of Appendix J1, there are several requirements of the PERP that do not clearly comply with the requirements of Section 7.7.1 of the ULDC. Alhough borrow areas are identified and haul routes are mapped, there is no indication that up to 324,000 CY of material can be generated from the available borrow pits. We agree material properties are less relevant in an emergency, but site size and potentail volume of available materials is relevant.

Appendix J1 and the revised Post Earthquake Remediation Plan provided for review.

J1-2 - SAFCA confirmed that sufficient material is present in the identified borrow sources to meet the needs of the PERP.  Comment Resolved.

Acepted - closed
1 Appendix C.

American River North ULDC
Water Surface Elevation Profiles -
MBK Engineers
Water Resources  Flood Control  Water Rights

TECHNICAL MEMORANDUM
DATE: July 1, 2024
PREPARED FOR: SAFCA
PREPARED BY: Michael Archer, P.E.

REVIEWED BY: Don Trieu, P.E.

SUBJECT: American River North Levee System - Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 2 2 Acronyms and Abbreviations
1-D one dimensional
2-D two dimensional
AEP annual exceedance probability
ARN American River north
cfs cubic feet per second
CVFED Central Valley Floodplain Evaluation and Delineation CVFPP Central Valley Flood Protection Plan
CVHS Central Valley Hydrology Study
DWR California Department of Water Resources
DWSE Design Water Surface Elevation
FEMA Federal Emergency Management Agency
HTOL Hydraulic Top of Levee
LAR Lower American River
MBK MBK Engineers
MTOL Minimum Top of Levee
NAS North Area Streams
NAVD88 North American Vertical Datum of 1988
NEMDC Natomas East Main Drainage Canal
RM River Mile
SAFCA Sacramento Area Flood Control Agency
SNRR Sacramento Northern Railroad
SVRP Seismic Vulnerability Restoration Profile
ULDC Urban Levee Design Criteria
ULOP Urban Level of Flood Protection
UPRR Union Pacific Railroad
USACE U.S. Army Corps of Engineers
WSE water surface elevation

1. Purpose
The Sacramento Area Flood Control Agency (SAFCA) is in the process of evaluating the levees within its jurisdictional boundaries for compliance with the State of California’s Urban Levee Design Criteria (ULDC) (DWR, 2012). This technical memorandum provides documentation of the determination of the hydraulic parameters listed in Table 1, which are necessary for the ULDC compliance evaluation of the American River North (ARN) levee system.

All elevations are referenced to the North American Vertical Datum of 1988 (NAVD88).

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 3 Table 1. ULDC Hydraulic Parameters
Parameter ULDC Definition
Design Water Surface Elevation (DWSE) Median 200-year water surface elevation (WSE) Minimum Top of Levee (MTOL)
DWSE plus the higher of
• 3 feet, or
• wind setup and wave runup
Hydraulic Top of Levee (HTOL)
The lower of
• DWSE plus 3 feet, or
• Median 500-year WSE
Seismic Vulnerability Restoration Profile (SVRP)
10-year water surface elevation plus the higher of
• 3 feet, or
• wind setup and wave runup

2. Study Area
The American River North (ARN) levee system protects the floodplain bounded on the south by the American River, on the west by the Natomas East Main Drainage Canal (NEMDC), on the north by Arcade Creek, and on the east by high ground (see Figure 1). The levee system is made up of the three levee segments summarized in Table 2.

Table 2. American River North Levee System
Levee Segment Length (feet) Upstream Limit Downstream Limit American River north levee 54,850 Arden Way NEMDC east levee Arcade Creek south levee 11,000 Marysville Blvd. NEMDC east levee NEMDC east levee 6,512 Arcade Creek south levee American River north levee Figure 1. American River North Levee System
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 4

3. Hydrology
Central Valley Hydrology Study (CVHS) procedures and hydrologic data were used in this analysis. The CVHS was commissioned by DWR and prepared by the USACE (USACE, 2015). For the Sacramento River and San Joaquin River basins, the CVHS defines a procedure in which a scaled flood event with a pattern based on a historical flood event is selected to represent the flood of a specific frequency at a specific location, or centering. The CVHS also developed hydrologic data for several smaller ungaged watersheds, including the Natomas-Area Stream Group, which includes Dry Creek, Robla Creek and Arcade Creek (USACE, 2013). The hydrologic data for the Natomas-Area Stream Group was developed for discrete Nyear flood frequencies with centerings defined by contributing area (C) parameters. The Natomas-Area Stream Group hydrologic data was updated by USACE in 2019. There are four CVHS defined flood centerings that influence the NAS model study area:
• Natomas-Area Stream Group: Dry Creek
• Natomas-Area Stream Group: Robla and Magpie Creeks
• Natomas-Area Stream Group: Arcade Creek
• Sacramento River Basin: American River at Fair Oaks and Latitude of Sacramento The ULDC requires the computation of water surface elevations for the 10-year, 200-year, and 500-year flood events. The Sacramento River Basin scaled flood events and Natomas-Area Stream Group C parameters for these flood frequencies and flood centerings are summarized in Table 3. The final computed maximum WSE is the composite maximum of the maximum WSE’s computed for the four flood centerings.

The County of Sacramento’s D-15 pump station, at the upstream end of the modeled NEMDC reach, is an inline pump station with gates (County of Sacramento, 2007). During large flood events the gates close automatically when the water surface elevation at the pump station reaches a pre-defined trigger elevation, preventing backwater due to high flows in Dry and Robla creeks from affecting flood stages north of the pump station. After the gates close, the pumps will automatically turn on to ensure positive flow from north to south. The station has three 333 cfs capacity pumps. The operation criteria specify a firm capacity based on use of two of the three pumps, keeping one for a backup. However, all three pumps may be operated concurrently if required. For the ULDC analysis, the conservative assumption of a three-pump operation, with a total flow of 999 cfs, was used.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 5 Table 3. CVHS Flood Events
Flood Centering
Flood
Frequency
(Recurrence
Interval)
Watershed
North Area Streams Sacramento River
Dry Creek 10-year 10yr_C=99.5 1 1995-60% 2, 3
200-year 200yr_C=99.5 1 1995-105% 2
500-year 500yr_C=99.5 1 1995-120% 2
Robla-Magpie Creeks 10-year 10yr_C=RIOLINDA_MAGPIE 1 1995-60% 2, 3 200-year 200yr_C=RIOLINDA_MAGPIE 1 1995-105% 2
500-year 500yr_C=RIOLINDA_MAGPIE 1 1995-120% 2
Arcade Creek 10-year 10yr_C=ARC 1 1995-60% 2, 3
200-year 200yr_C=ARC 1 1995-105% 2
500-year 500yr_C=ARC 1 1995-120% 2
Fair Oaks-latitude of
Sacramento 10-year 1986-55% 2 1986-55% with 40% on American R. 1, 2 200-year 1986-110% 2 1986-110% with 125% on
American R. 2
500-year 1986-100% 4 1986-100% with 176% on
American R. 4
1 Data ID from USACE 2019 updated hydrologic data set.
2 Event selection by USACE (USACE, 2019). “1995-60%” = 1995 flood pattern with a 60% scale factor. 3 CVHS hydrologic data does not include the 1995-60% flood event. The closest available flood event data, 1995-75%, was used in the analysis. The 1995-75% data approximately represents the 20-year flood event. 4 Event selection by USACE (USACE, 2020).

4. Hydraulic Model
Four HEC-RAS1 hydraulic models were used to determine the ULDC water surface elevations for the American River North levee system:

1. Lower American River (LAR) model

2. North Area Streams (NAS) model

3. Sacramento River system model, 2019 version

4. Sacramento River system model, 2016 version
1 HEC-RAS is software developed by the USACE Hydrologic Engineering Center for the purpose of performing one-dimensional (1-D) and two-dimensional (2-D) hydraulic calculations for a full network of natural and constructed channels (USACE, 2023a).

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 6 The four models were used to leverage previously developed models and minimize the need for new model development.

4.1. Lower American River (LAR) Model
The LAR model is a 1-D model consisting of the American River from Nimbus Dam (Lake Natoma) to the Sacramento River, and the NEMDC from Arcade Creek to the Sacramento River. It was adapted by MBK from the Sacramento River Watershed HEC-RAS model developed for the DWR Central Valley Floodplain Evaluation and Delineation (CVFED) project (Wood Rodgers, 2015). A schematic of the LAR model is provided in Figure 2. The LAR model was developed and executed with version 6.4.1 of HEC-RAS.

Figure 2. Lower American River HEC-RAS Model Schematic
The LAR model was calibrated using the January 1997 flood event, which had a peak American River flow of about 117,000 cfs. On February 10, 2017, when the flow in the lower American River was about 85,000 cfs, cbec Eco-engineering surveyed the water surface elevation at several locations. A simulation of the February 10, 2017, conditions was made to verify the model calibration. The results of the calibration and verification simulations are provided in Appendix A.

The LAR model was used to compute the ULDC WSE’s for the American River north levee.

4.2. North Area Streams (NAS) Model
The NAS model is a combined 1-D and 2-D model consisting of the stream reaches summarized in Table

4. The model was developed by MBK from an existing 1-D model, which was modified to use 2-D flow areas for reaches with small low flow channels and wide floodways, such as Dry Creek, Robla Creek and Magpie Creek. The 1-D elements are adapted from the CVFED modeling. A schematic of the model is provided in Figure 3. The downstream boundary of the model is the NEMDC at the American River north levee. WSE’s computed by the LAR model were used to define the downstream boundary condition of the NAS model The NAS model was developed and executed with version 6.4.1 of HEC-RAS.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 7 Table 4. Streams Within the Model Study Area
Stream Upstream Boundary Downstream Boundary Model
Element
Length
(miles)
Dry Creek Below Q Street NEMDC 2-D 3.5
Robla Creek Above 16th Street NEMDC 2-D 3.3
Magpie Creek Patrol Road Robla Creek 2-D 1.8
Don Julio Creek Patrol Road Magpie Creek 2-D 1.3
Arcade Creek Auburn Blvd. NEMDC 1-D 6.6
NEMDC D-15 Pump Station American R. north levee 1-D 4.3 Figure 3. North Area Stream HEC-RAS Model Schematic
A terrain model is required for 2-D modeling, as it is used to establish the geometric and hydraulic properties within 2-D flow areas. The primary terrain used for the NAS model was developed by USACE for use in their hydraulic analysis of the Magpie Creek project (USACE, 2021). The USACE terrain did not provide coverage of the entire NAS model study area, as shown in Figure 4. Terrain developed for the CVFED program (Wood Rodgers, 2014) was used to extend coverage to the entire NAS model study area, SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 8 as shown in Figure 5. The vertical and horizontal accuracy and resolution of the USACE terrain is not provided in the referenced documentation. The CVFED terrain has a vertical accuracy of 0.6 feet, a horizontal accuracy of 3.5 feet, and an average point spacing of 3.28 feet.

Figure 4. USACE Terrain Coverage (elevations are Figure 5. Final Terrain Coverage (elevations are in in feet NAVD88) feet NAVD88)
Manning’s n roughness coefficient values within the 2-D flow areas were defined using land classification mapping from the National Land Cover Database, as shown in Figure 6. Manning’s n-values were initially assigned for the various land classifications based on recommendations in the HEC-RAS 2D User’s Manual (USACE, 2023b), and refined as necessary through the calibration process. The land classifications and final associated n-values are listed in Table 5.

Table 5. Land Classifications and Assigned Manning’s n-values Land Classification Manning’s
n-value Land Classification Manning’s n-value
Barren Land Rock-Sand-Clay 0.035 Emergent Herbaceous Wetlands 0.06 Cultivated Crops 0.038 Evergreen Forest 0.08
Deciduous Forest 0.08 Grassland-Herbaceous 0.035
Developed, High Intensity 0.10 Open Water 0.03
Developed, Low Intensity 0.05 Pasture-Hay 0.042
Developed, Medium Intensity 0.07 Shrub-Scrub 0.08
Developed, Open Space 0.04 Woody Wetlands 0.07
The model was calibrated to the high flow event that occurred during the end of December 2005 and the beginning of January 2006 (the “2006 flood”). Calibration results are provided and summarized in Appendix B.

The NAS model was used to compute the ULDC WSE’s for the NEMDC east levee and the Arcade Creek south levee.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 9 Figure 6. Land Classification Map

4.3. Sacramento River System Models
The Sacramento River System models include the Sacramento River from Colusa at the upstream end to Collinsville at the downstream end, at the confluence of the Sacramento River and San Joaquin River in the eastern Sacramento-San Joaquin Delta. These models were used to compute the WSE at the mouth of the American River for use as downstream boundary conditions for the LAR model, accounting for the effects of sea level rise, as required by the ULDC, and the Federally authorized and under construction Sacramento Weir Widening project. The original intent had been to use the 2019 version, which had been used by MBK for a hydraulic impact analysis for the Sacramento Weir Widening Project (MBK Engineers, 2019), for the analysis. However, the 2019 analysis did not include simulations of the CVHS 1995 pattern flood events necessary for the Arcade Creek, Robla-Magpie Creeks, and Dry Creek flood centerings (see Table 3). Attempts were made to simulate the 1995 pattern flood events with the 2019 model, but these proved to be problematic. An earlier analysis was found that was made with the 2016 version of the SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 10 model and included simulations of the CVHS 1995 pattern flood events. Due to time constraints, it was decided to use the 2016 version of the model to compute the 1995 pattern WSE’s at the mouth of the American River for use as boundary conditions for the LAR model.

The 2019 version used HEC-RAS 5.0.7, and the 2016 model used HEC-RAS 5.0.1.

5. Urban Levee Design Criteria (ULDC)
Section 7.1 of the ULDC allows for two options for the determination of the DWSE. The first option is the Federal Emergency Management Agency (FEMA) Approach, in which the DWSE is computed deterministically with a hydraulic model. The second option is the U.S. Army Corps of Engineers Approach, which incorporates uncertainty into the determination of the DWSE. The approach selected for this analysis was the FEMA Approach, due to its application and results being more straightforward and economical.

The ULDC defines the DWSE as the “200-year stage or water level used to design a levee or floodwall”.

Section 7.1.1 of the ULDC specifies that the hydraulic modeling used to determine the DWSE must consider the following:
• Upstream, downstream, and nearby levees and floodwalls protecting urban areas are assumed to be raised to the median 200-year water surface elevation plus 3 feet and not allowed to breach, even if overtopped. Overtopping flows are assumed to leave the channel and remain in the 200- year floodplain.
• All project levees and floodwalls are to be modeled to incorporate a minimum crown elevation equal to the authorized (usually the 1955/1957) USACE design profiles – this affects nonurbanized areas for the most part – all such levees and floodwalls are to be allowed to overtop, act as weirs, and not breach for floods up to and including the median 500-year flood.

Overtopping flows are assumed to leave the channel and remain in the 200-year floodplain. • Non-project levees and floodwalls in non-urbanized areas in the region, to the extent they may affect the DWSE, are to be modeled at their existing or authorized height, whichever is higher, and to act as weirs without breaching if overtopped.
• Debris loading on bridges must be considered. Bridges with less than 3 feet of clearance above the DWSE may experience extraordinary debris loading that must be evaluated in addition to typical pier/bent debris loading. The evaluation should include historic and potential debris transport in the stream, an analysis of loading on the bridge, and analysis of backwater impacts on the DWSE in the vicinity of the bridge.

Section 7.1.3 of the ULDC requires adjustments to the DWSE for the effects of superelevation, when applicable. Superelevation is a tilting of the water surface, which may occur as water flows through a bend in the channel. Computational methods for determining superelevation adjustments are in the USACE Engineering Manual 1110-2-1601.

Section 7.1.3 of the ULDC also states that the “…the civil engineer should consider increasing the DWSE to account for the potential increases in water surface associated with climate change, updated hydrology, updated hydraulic models, and sea level rise”. This statement implies that adjustment for sea level rise is SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 11 optional; however, Section 7.19 of the ULDC states, “the effects of sea level rise are to be estimated and addressed for the duration during which a Finding that the urban level of flood protection exists may be valid”. Based on the second statement, sea level rise adjustment appears to be mandatory.

Additionally, Section 7.1.3 of the ULDC states:
“[T]he civil engineer also needs to address two other situations: (1) whether upstream levee or floodwall breaches could produce overland flows that would reach the area protected by the levee system or increase the water surface elevation along the levee system, and (2) whether flooding in a nearby leveed area could fill that area and breach a nearby levee or floodwall, returning flow to the stream and increasing the DWSE for a portion of the levee system".

Neither of these conditions are applicable to the Study Area, and therefore were not evaluated.

The following sections address the requirements in the ULDC and discuss the application of each requirement for the American River North levee system.

5.1 Levees
As per the ULDC, all urban levees were assumed to have a minimum top elevation of the median 200-year water surface elevation plus 3 feet. All non-urban State-Federal Project levees were assumed to have a minimum crown elevation equal to the authorized USACE design profiles.

5.2 Debris Loading
The ULDC specifies that debris loading on bridges must be considered, and that “bridges with less than 3 feet of clearance above the DWSE may experience extraordinary debris loading that must be evaluated in addition to typical pier/bent debris loading”.

Bridge pier debris are applied in accordance with guidelines provided in a July 2014 letter, sent by USACE to the California Central Valley Flood Protection Board in order to clarify the level of screening and analysis that should be included on encroachment permit applications that are sent to the USACE for review. A copy of the letter is provided in Appendix C. Included in the letter was guidance for modeling debris build-up. Based on this guidance, under the ULDC “typical” debris loading condition, the hydraulic analysis included floating debris with a width equal to double the pier width, and a depth of 2 feet below the water surface. Under the ULDC “extraordinary” debris loading condition, floating debris with a depth of 2 feet below the water surface were modeled for the full width with the “extraordinary” condition.

Debris were not applied to bridges in the model upstream of the levee reaches, as debris on these bridges would have no effect on the water surface elevation in the levee reaches.

A summary of the bridge pier debris conditions included in the hydraulic analysis is provided in Table 6.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 12 Table 6. Bridge Pier Debris Loading
River River
Station1 Bridge Debris Loading Condition2
200-yr 500-yr
Dry Creek West Branch 1,340 ft Rio Linda Blvd. E E
Dry Creek East Branch 3,910 ft SNRR Bike Trail t t
640 ft Rio Linda Blvd. E E
Dry Creek (lower) 6,120 ft private bridge E E
110 ft UPRR (near mouth) E E
Robla Creek 9,680 ft SNRR Bike Trail E E
8,290 ft Rio Linda Blvd. E E
90 ft UPRR (near mouth) E E
Magpie Creek 6,120 ft Raley Blvd. E E
4,010 ft Vinci Ave. E E
1,130 ft Dry Creek Rd. E E
Arcade Creek 1.344 mi Rio Linda Blvd. E E

1.26 mi SNRR Bike Trail E E

0.722 mi Norwood Avenue E E

0.045 mi UPRR (near mouth) E E
NEMDC 6.139 mi Main Avenue t t

5.168 mi Interstate 80 t t

4.347 mi Silver Eagle Road t t

3.03 mi West El Camino Avenue mix E

2.653 mi Arden-Garden Connector t t
American River 13.46 mi Bike Trail bridge t E

9.31 mi Watt Ave t E

7.748 mi Howe Ave t E

7.065 mi Guy West t E

6.588 mi H St t E

3.989 mi Cap City Fwy t t

3.715 mi RR t E

2.333 mi RR t E

2.235 mi Bike Trail t E

2.068 mi CA-160 E t mix

2.046 mi CA-160 W t mix

0.355 mi I-5 t mix

0.242 mi Jibboom St mix E
1 River station in miles for 1-D reaches and in feet for 2-D flow areas. 2 t = typical; E = extraordinary; mix = combination of t and E.

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American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 13

5.3 Superelevation
Superelevation is a tilting of the water surface that occurs on the outside of a river bend. The ULDC notes that, “on the outside of a bend, the superelevation needs to be added to the DWSE”. The superelevation adjustment, per USACE Engineer Manual 1110-2-1416, River Hydraulics, is specific to 1-D hydraulic modeling. There are three locations in the ARN levee system where the superelevation adjustment applies (see Figure 7):
• American River, River Mile (RM) 5.7
• American River, RM 3.6
• NEMDC, RM 2.6
As recommended in the ULDC, computational methods in USACE Engineering Manual 1110-2-1601 were used to compute superelevation. Superelevation is computed with the following equation:
y = CV2
W/gr
where
y = superelevation (feet)
C = coefficient = 0.5 (tranquil, or subcritical, flow)
V = mean channel velocity (feet/second)
W = channel width at elevation of center-line water surface (feet) g = acceleration of gravity (32.2 feet/second2)
r = radius of channel center-line curvature
Figure 7. Superelevation Evaluation Locations
The computed superelevation and corresponding parameters are summarized in Table 7.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 14 Table 7. Superelevation
Location
r
(feet)
1/200 AEP 1/500 AEP
V
(feet/
second)
W
(feet)
Superelevation
(feet)
V
(feet/
second)
W
(feet)
Superelevation
(feet)
American R, RM 5.6 1,300 3.7 1,920 0.3 4.2 2,030 0.4
American R, RM 3.6 2,900 4.4 2,290 0.2 4.5 2,330 0.3
NEMDC, RM 2.6 1,900 2.4 470 0.0 3.4 500 0.0
The American River RM 5.6 superelevation adjustment was applied to the computed water surface elevations at cross sections 5.682 and 5.502. The American River RM 3.6 superelevation adjustment was applied to the computed water surface elevations at cross sections 3.735, 3.688 and 3.600. No superelevation adjustment was needed at the NEMDC RM 2.6 location.

5.4 Climate Change
The effects of climate change on extreme precipitation events in the Central Valley are being studied, but there is no indication of what the outcome of that work will be. Therefore, the hydrology used in this analysis has not been adjusted for the effects of climate change.

5.5 Updated Hydrology
This analysis makes use of the most recent accepted hydrologic data for the Study Area, which was developed as part of the Central Valley Hydrology Study, as noted in Section 4 of this report.

5.6 Updated Hydraulic Model
The hydraulic model used for this analysis was developed from the most current available data. Due to the calibration process, an updated hydraulic model would not be expected to have a substantial effect on the computed results unless significant physical changes have occurred in the modeled system. Since no significant physical changes have occurred since the data used for the model development was collected, no adjustment for updated hydraulic model has been included.

5.7 Sea Level Rise
The ULDC notes that, “the effects of sea level rise are to be estimated and addressed for the duration during which a Finding that the urban level of flood protection exists may be valid”. The duration of finding proposed for the subject project is 20 years.

The analysis assumed a sea level rise of 3.68 feet at San Francisco. This is the 50-year sea level rise projection determined by DWR for the 2022 update of the Central Valley Flood Protection Plan (CVFPP) (DWR, 2022). Being that the duration of the Urban Level of Protection finding is 20 years, the use of a 50- year projection is a conservative assumption. The effects of this sea level rise were applied at the downstream boundaries of the Sacramento River systemwide hydraulic model simulations, which were used to determine the downstream boundary conditions for the LAR model.

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American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 15

6. Computed ULDC Hydraulic Parameters
The following sections present the computed ULDC hydraulic parameters that were described in Section 1 of this technical memorandum:
• Design Water Surface Elevation (DWSE)
• Minimum Top of Levee (MTOL)
• Hydraulic Top of Levee (HTOL)
• Seismic Vulnerability Restoration Profile

6.1 Design Water Surface Elevation (DWSE)
The ULDC defines the DWSE as “[the] median 200-year water surface elevation”, with adjustments for the following factors:
• Bridge pier debris loading
• Superelevation
• Sea level rise
Debris loading and sea level rise are accounted for in the hydraulic model simulations, as described in Sections 5.2 and 5.7. As noted in Section 5.3, the superelevation adjustment was applied at two locations on the American River north levee.

Profile plots of the computed DWSE for each of the levee segments in the ARN levee system are provided in Figures 8, 9 and 10. The levee crest profiles are included on the profile plots. Tabulations of the DWSE profiles are provided in Appendix D.

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American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 16 Figure 8. ULDC DWSE Profile, American River North Levee Figure 9. ULDC DWSE Profile, Arcade Creek South Levee
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 17 Figure 10. ULDC DWSE Profile, NEMDC East Levee

6.2 Minimum Top of Levee (MTOL)
The ULDC defines the MTOL as the higher of the DWSE plus 3 feet, or the DWSE plus the computed wind setup and wave runup. Wind setup and wave runup for the ARN levee system has been computed by Mead & Hunt (Mead & Hunt, 2024). The maximum computed wind setup and wave runup is 3.0 feet.

Since this does not exceed 3 feet, the MTOL for the ARN levee system levees is the DWSE plus 3 feet.

Profile plots of the MTOL for each of the levee segments in the ARN levee system are provided in Figures 11, 12 and 13. Tabulation of the MTOL profiles are provided in Appendix D.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 18 Figure 11. ULDC MTOL Profile, American River North Levee Figure 12. ULDC MTOL Profile, Arcade Creek South Levee
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 19 Figure 13. ULDC MTOL Profile, NEMDC East Levee

6.3. Hydraulic Top of Levee (HTOL)
The ULDC defines the HTOL as the lower of the DWSE plus 3 feet, or the median 500-year WSE. Profile plots of the HTOL for each of the levee segments in the ARN levee system are provided in Figures 14, 15 and 16. For reference, the DWSE plus 3 feet and 500-year WSE profiles are also shown. Tabulations of the HTOL profiles are provided in Appendix D.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 20 Figure 14. ULDC HTOL Profile, American River North Levee Figure 15. ULDC HTOL Profile, Arcade Creek South Levee
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 21 Figure 16. ULDC HTOL Profile, NEMDC East Levee

6.4 Seismic Vulnerability Restoration Profile (SVRP)
The ULDC specifies that if there is the potential for levee damage due to a seismic event, a plan needs to be in place to “restore grade and dimensions for at least 10-year WSE plus 3 feet of freeboard or higher for wind setup and wave runup within 8 weeks”. An evaluation of seismic performance of the American River North levee system by Kleinfelder (Kleinfelder, 2024) determined that there were locations on the American River north levee that have high seismic vulnerability, as defined in the DWR Urban Levee Evaluation (ULE) program, and that the Arcade Creek south levee and NEMDC east levee have low seismic vulnerability. Therefore, the seismic vulnerability restoration profile has been developed for the American River north levee, but is unnecessary for the Arcade Creek south levee and NEMDC east levee. A profile plot of the seismic vulnerability restoration profile for the American River north levee is provided in Figure17. A tabulation of the seismic vulnerability restoration profile is included in Appendix D.

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American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 22 Figure 17. Seismic Vulnerability Restoration Profile, American River North Levee SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 23 References
County of Sacramento. (2007). D-15 NEMDC Drainage Pump Station Summary of Operations and Procedures Manual. May 2007.

DWR. (2012). Urban Levee Design Criteria. May 2012.

DWR. (2022). 2022 CVFPP Update - Technical Analyses Summary Report. November 2022.

Kleinfelder. (2024). Seismic Performance Summary Report, North Area Streams Levee Areas. February 12, 2024.

MBK Engineers. (2019). Technical Memorandum - Sacramento Weir Widening Project, Initial Hydraulic Impact Analysis. October 31, 2019.

Mead & Hunt. (2024). Wind-Wave Analysis for American River North and Robla-Arcade Levee Systems.

January 16, 2024.

USACE. (2013). Central Valley Hydrology Study: Natomas-area Stream Group - Pleasant Grove Creek, Dry Creek, and Arcade Creek Watersheds Hydrologic Analysis. March 26, 2013.

USACE. (2015). Central Valley Hydrology Study. November 29, 2015.

USACE. (2019). Memorandum for Record, Subject: CVHS Hydrograph Package for HEC-RAS Model Inputs. February 20, 2019.

USACE. (2020). Hydrology Technical Memorandum for Developing WRDA 2016 Water Surface Profiles.

April 10, 2020.

USACE. (2021). Hydraulic Model Summary Magpie Creek Canal For American River Common Features Project. USACE - Vicksburg District. April 2021.

USACE. (2023a). HEC-RAS User's Manual. Retrieved from
https://www.hec.usace.army.mil/confluence/rasdocs/rasum/6.4 USACE. (2023b). HEC-RAS 2D User's Manual. Retrieved from https://www.hec.usace.army.mil/confluence/rasdocs/r2dum/latest Wood Rodgers. (2014). Central Valley Floodplain Evaluation and Delineation, Lower Sacramento River Technical Memorandum. January 17, 2014.

Wood Rodgers. (2015). Refine/Calibrate Combined Sacramento River and San Joaquin River Systems, Sacramento River System Study Area Report. May 29, 2015.

APPENDIX A
Lower American River
Hydraulic Model Calibration
Simulation Event Peak American River flow
Calibration January 1997 flow 117,000 cfs
Verification February 10, 2017 ~85,000 cfs
Figure A-1. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River river miles 10 to 23 (Mayhew Drain to Nimbus Dam) Figure A-2. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River river miles 0 to 11 (Sacramento River to Mayhew Drain) Figure A-3. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevation, American River river miles 10 to 23 (Mayhew Drain to Nimbus Dam)
Figure A-4. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevation, American River river miles 0 to 11 (Sacramento River to Mayhew Drain)

Figure A-1. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River, river miles 10 to 23 (Mayhew Drain to Nimbus Dam) Figure A-2. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River, river miles 0 to 11 (Sacramento River to Mayhew Drain)

Figure A-3. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevations, American River, river miles 10 to 23 (Mayhew Drain to Nimbus Dam) Figure A-4. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevations, American River, river miles 0 to 11 (Sacramento River to Mayhew Drain)

APPENDIX B
North Area Streams
Hydraulic Model Calibration
B-1
Calibration flood event: December 2005-January 2006
The stream gages listed in Table B-1 provided the available observed data used for calibration of the Dry Creek and Robla Creek watershed area. All the gages are part of the Sacramento County ALERT system (https://www.sacflood.org/). The gage data was provided by Sacramento County. The gage locations are shown in Figure B-1.

Table B-1. Stream Gages with Observed Data Available for Calibration Gage Agency Sensor ID
Dry Creek West Branch at SNRR Bike Trail Sacramento County ALERT 2230 Dry Creek West Branch at Elkhorn Blvd. Sacramento County ALERT 1661 Dry Creek Bypass at Elkhorn Blvd. Sacramento County ALERT 1662 Dry Creek East Branch at Elkhorn Blvd. Sacramento County ALERT 2782 Robla Creek at SNRR Bike Trail Sacramento County ALERT 2753 D15/NEMDC Downstream Sacramento County ALERT 2772
Figure B-1. Stream Gage Location Map
A comparison of the observed and computed peak stages at the gage locations is provided in Table B-2.

Profile plots of the computed maximum water surface elevations with available observed gage peaks are B-2
provided in Figures B-2 through B-6.

Table B-2. Calibration Results, Comparison of Observed and Computed Peak Stages Gage Maximum Stage (feet NAVD88) Difference
Observed Computed (feet)
Dry Creek West Branch at SNRR Bike Trail 47.62 48.06 +0.44 Dry Creek West Branch at Elkhorn Blvd. 46.06 46.17 +0.11 Dry Creek Bypass at Elkhorn Blvd. 46.95 46.58 -0.37
Dry Creek East Branch at Elkhorn Blvd. 46.88 49.33 +2.45 a Robla Creek at SNRR Bike Trail 40.59 40.78 +0.19
D15/NEMDC Downstream 36.44 36.69 +0.25
a The Sacramento County ALERT website for this gage notes that “when the east branch reaches 49.9’ +/- the stage at the west branch is approximately 46.5’ +/-“. The computed peak stage difference for these locations of 3.2’ is similar to the reported difference of 3.6’. Therefore, it can be concluded that the reported peak stage of 46.88’ at the Dry Creek East Branch at Elkhorn Blvd gage is suspect.

Figure B-2. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek West Branch B-3
Figure B-3. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek East Branch Figure B-4. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek (lower) B-4
Figure B-5. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek Bypass Channel Figure B-6. Calibration Analysis Maximum Water Surface Elevation Profile, Robla Creek

Appendix C
USACE Letter with Debris Loading Guidance
C-1
C-2
C-3
C-4
C-5
C-6
C-7
C-8
C-9

APPENDIX D

Tabulation of ULDC Hydraulic Parameter Profiles for the American River North Levee System Profile Acronyms:

DWSE design water surface elevation
MTOL minimum top of levee
HTOL hydraulic top of levee
SVRP seismic vulnerability restoration profile
D-1
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3000+00 35.64 38.64 38.64 34.46 3052+00 37.09 40.09 40.09 35.52 3001+00 35.61 38.61 38.61 34.47 3053+00 37.10 40.10 40.10 35.53 3002+00 35.58 38.58 38.58 34.48 3054+00 37.11 40.11 40.11 35.53 3003+00 35.55 38.55 38.55 34.48 3055+00 37.12 40.12 40.12 35.54 3004+00 35.52 38.52 38.52 34.49 3056+00 37.14 40.14 40.14 35.55 3005+00 35.50 38.50 38.50 34.50 3057+00 37.15 40.15 40.15 35.56 3006+00 35.47 38.47 38.47 34.51 3058+00 37.16 40.16 40.16 35.57 3007+00 35.48 38.48 38.48 34.51 3059+00 37.17 40.17 40.17 35.58 3008+00 35.49 38.49 38.49 34.52 3060+00 37.18 40.18 40.18 35.59 3009+00 35.51 38.51 38.51 34.53 3061+00 37.20 40.20 40.20 35.60 3010+00 35.52 38.52 38.52 34.54 3062+00 37.21 40.21 40.21 35.61 3011+00 35.53 38.53 38.53 34.55 3063+00 37.23 40.23 40.23 35.63 3012+00 35.55 38.55 38.55 34.56 3064+00 37.24 40.24 40.24 35.64 3013+00 35.56 38.56 38.56 34.56 3065+00 37.26 40.26 40.26 35.65 3014+00 35.55 38.55 38.55 34.56 3066+00 37.27 40.27 40.27 35.66 3015+00 35.55 38.55 38.55 34.55 3067+00 37.29 40.29 40.29 35.67 3016+00 35.91 38.91 38.91 34.77 3068+00 37.30 40.30 40.30 35.68 3017+00 35.99 38.99 38.99 34.82 3069+00 37.32 40.32 40.32 35.69 3018+00 36.07 39.07 39.07 34.89 3070+00 37.34 40.34 40.34 35.70 3019+00 36.15 39.15 39.15 34.94 3071+00 37.37 40.37 40.37 35.71 3020+00 36.29 39.29 39.29 35.02 3072+00 37.40 40.40 40.40 35.71 3021+00 36.28 39.28 39.28 35.00 3073+00 37.44 40.44 40.44 35.72 3022+00 36.30 39.30 39.30 35.00 3074+00 37.47 40.47 40.47 35.72 3023+00 36.32 39.32 39.32 35.01 3075+00 37.50 40.50 40.50 35.72 3024+00 36.33 39.33 39.33 35.02 3076+00 37.53 40.53 40.53 35.73 3025+00 36.35 39.35 39.35 35.03 3077+00 37.57 40.57 40.57 35.74 3026+00 36.36 39.36 39.36 35.04 3078+00 37.63 40.63 40.63 35.79 3027+00 36.38 39.38 39.38 35.04 3079+00 37.69 40.69 40.69 35.83 3028+00 36.40 39.40 39.40 35.05 3080+00 37.75 40.75 40.75 35.87 3029+00 36.41 39.41 39.41 35.06 3081+00 37.81 40.81 40.81 35.91 3030+00 36.43 39.43 39.43 35.07 3082+00 37.87 40.87 40.87 35.95 3031+00 36.44 39.44 39.44 35.08 3083+00 37.92 40.92 40.92 35.99 3032+00 36.46 39.46 39.46 35.08 3084+00 37.94 40.94 40.94 36.02 3033+00 36.48 39.48 39.48 35.09 3085+00 37.87 40.87 40.87 35.97 3034+00 36.49 39.49 39.49 35.10 3086+00 38.06 41.06 41.06 36.12 3035+00 36.54 39.54 39.54 35.13 3087+00 38.06 41.06 41.06 36.13 3036+00 36.58 39.58 39.58 35.16 3088+00 38.05 41.05 41.05 36.13 3037+00 36.63 39.63 39.63 35.18 3089+00 38.05 41.05 41.05 36.13 3038+00 36.67 39.67 39.67 35.21 3090+00 38.04 41.04 41.04 36.14 3039+00 36.72 39.72 39.72 35.25 3091+00 38.03 41.03 41.03 36.14 3040+00 36.77 39.77 39.77 35.28 3092+00 38.03 41.03 41.03 36.14 3041+00 36.83 39.83 39.83 35.32 3093+00 38.02 41.02 41.02 36.14 3042+00 36.88 39.88 39.88 35.36 3094+00 38.01 41.01 41.01 36.15 3043+00 36.92 39.92 39.92 35.39 3095+00 38.01 41.01 41.01 36.15 3044+00 36.95 39.95 39.95 35.41 3096+00 38.00 41.00 41.00 36.15 3045+00 36.98 39.98 39.98 35.43 3097+00 37.99 40.99 40.99 36.16 3046+00 37.01 40.01 40.01 35.45 3098+00 37.99 40.99 40.99 36.16 3047+00 37.03 40.03 40.03 35.47 3099+00 37.98 40.98 40.98 36.16 3048+00 37.04 40.04 40.04 35.48 3100+00 37.99 40.99 40.99 36.17 3049+00 37.06 40.06 40.06 35.49 3101+00 38.02 41.02 41.02 36.20 3050+00 37.07 40.07 40.07 35.50 3102+00 38.14 41.14 41.14 36.27 3051+00 37.08 40.08 40.08 35.51 3103+00 38.09 41.09 41.09 36.22 D-2
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3104+00 38.12 41.12 41.12 36.23 3156+00 40.06 43.06 43.06 37.93 3105+00 38.15 41.15 41.15 36.26 3157+00 40.11 43.11 43.11 37.99 3106+00 38.19 41.19 41.19 36.29 3158+00 40.13 43.13 43.13 38.00 3107+00 38.22 41.22 41.22 36.32 3159+00 40.15 43.15 43.15 38.01 3108+00 38.25 41.25 41.25 36.34 3160+00 40.16 43.16 43.16 38.02 3109+00 38.28 41.28 41.28 36.36 3161+00 40.18 43.18 43.18 38.03 3110+00 38.31 41.31 41.31 36.38 3162+00 40.19 43.19 43.19 38.04 3111+00 38.34 41.34 41.34 36.40 3163+00 40.21 43.21 43.21 38.05 3112+00 38.37 41.37 41.37 36.42 3164+00 40.22 43.22 43.22 38.06 3113+00 38.41 41.41 41.41 36.44 3165+00 40.24 43.24 43.24 38.06 3114+00 38.43 41.43 41.43 36.45 3166+00 40.25 43.25 43.25 38.07 3115+00 38.43 41.43 41.43 36.45 3167+00 40.27 43.27 43.27 38.08 3116+00 38.43 41.43 41.43 36.44 3168+00 40.28 43.28 43.28 38.09 3117+00 38.43 41.43 41.43 36.44 3169+00 40.32 43.32 43.32 38.11 3118+00 38.44 41.44 41.44 36.43 3170+00 40.39 43.39 43.39 38.15 3119+00 38.44 41.44 41.44 36.43 3171+00 40.45 43.45 43.45 38.18 3120+00 38.44 41.44 41.44 36.43 3172+00 40.51 43.51 43.51 38.21 3121+00 38.44 41.44 41.44 36.42 3173+00 40.58 43.58 43.58 38.25 3122+00 38.44 41.44 41.44 36.42 3174+00 40.64 43.64 43.64 38.28 3123+00 38.45 41.45 41.45 36.42 3175+00 40.71 43.71 43.71 38.32 3124+00 38.50 41.50 41.50 36.46 3176+00 40.77 43.77 43.77 38.35 3125+00 38.57 41.57 41.57 36.53 3177+00 40.83 43.83 43.83 38.39 3126+00 38.64 41.64 41.64 36.59 3178+00 40.90 43.90 43.90 38.42 3127+00 38.71 41.71 41.71 36.66 3179+00 40.96 43.96 43.96 38.45 3128+00 38.78 41.78 41.78 36.73 3180+00 41.02 44.02 44.02 38.49 3129+00 38.85 41.85 41.85 36.79 3181+00 41.05 44.05 44.05 38.51 3130+00 38.92 41.92 41.92 36.86 3182+00 41.07 44.07 44.07 38.53 3131+00 38.99 41.99 41.99 36.93 3183+00 41.10 44.10 44.10 38.55 3132+00 39.06 42.06 42.06 36.99 3184+00 41.12 44.12 44.12 38.58 3133+00 39.10 42.10 42.10 37.03 3185+00 41.15 44.15 44.15 38.60 3134+00 39.14 42.14 42.14 37.05 3186+00 41.17 44.17 44.17 38.62 3135+00 39.17 42.17 42.17 37.07 3187+00 41.19 44.19 44.19 38.65 3136+00 39.20 42.20 42.20 37.10 3188+00 41.22 44.22 44.22 38.67 3137+00 39.23 42.23 42.23 37.12 3189+00 41.24 44.24 44.24 38.69 3138+00 39.27 42.27 42.27 37.15 3190+00 41.27 44.27 44.27 38.71 3139+00 39.30 42.30 42.30 37.18 3191+00 41.29 44.29 44.29 38.74 3140+00 39.34 42.34 42.34 37.21 3192+00 41.31 44.31 44.31 38.76 3141+00 39.39 42.39 42.39 37.25 3193+00 41.30 44.30 44.30 38.78 3142+00 39.43 42.43 42.43 37.28 3194+00 41.30 44.30 44.30 38.81 3143+00 39.47 42.47 42.47 37.31 3195+00 41.29 44.29 44.29 38.83 3144+00 39.51 42.51 42.51 37.35 3196+00 41.28 44.28 44.28 38.85 3145+00 39.55 42.55 42.55 37.38 3197+00 41.28 44.28 44.28 38.88 3146+00 39.59 42.59 42.59 37.41 3198+00 41.27 44.27 44.27 38.90 3147+00 39.63 42.63 42.63 37.45 3199+00 41.27 44.27 44.27 38.92 3148+00 39.67 42.67 42.67 37.49 3200+00 41.26 44.26 44.26 38.95 3149+00 39.72 42.72 42.72 37.55 3201+00 41.25 44.25 44.25 38.97 3150+00 39.77 42.77 42.77 37.60 3202+00 41.25 44.25 44.25 38.99 3151+00 39.82 42.82 42.82 37.66 3203+00 41.22 44.22 44.22 38.97 3152+00 39.87 42.87 42.87 37.71 3204+00 41.19 44.19 44.19 38.95 3153+00 39.92 42.92 42.92 37.77 3205+00 41.15 44.15 44.15 38.93 3154+00 39.96 42.96 42.96 37.82 3206+00 41.12 44.12 44.12 38.91 3155+00 40.01 43.01 43.01 37.88 3207+00 41.09 44.09 44.09 38.89 D-3
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3208+00 41.06 44.06 44.06 38.87 3260+00 43.77 46.77 46.77 41.24 3209+00 41.03 44.03 44.03 38.85 3261+00 43.83 46.83 46.83 41.28 3210+00 41.00 44.00 44.00 38.83 3262+00 43.89 46.89 46.89 41.31 3211+00 40.97 43.97 43.97 38.81 3263+00 43.95 46.95 46.95 41.35 3212+00 40.94 43.94 43.94 38.79 3264+00 44.01 47.01 47.01 41.39 3213+00 40.92 43.92 43.92 38.78 3265+00 44.32 47.32 47.32 41.62 3214+00 41.03 44.03 44.03 38.89 3266+00 44.41 47.41 47.41 41.68 3215+00 41.15 44.15 44.15 38.99 3267+00 44.50 47.50 47.50 41.74 3216+00 41.26 44.26 44.26 39.10 3268+00 44.59 47.59 47.59 41.80 3217+00 41.38 44.38 44.38 39.21 3269+00 44.67 47.67 47.67 41.86 3218+00 41.49 44.49 44.49 39.32 3270+00 44.76 47.76 47.76 41.92 3219+00 41.60 44.60 44.60 39.40 3271+00 44.85 47.85 47.85 41.98 3220+00 41.69 44.69 44.69 39.46 3272+00 44.96 47.96 47.96 42.07 3221+00 41.79 44.79 44.79 39.53 3273+00 45.10 48.10 48.10 42.18 3222+00 41.89 44.89 44.89 39.60 3274+00 45.23 48.23 48.23 42.29 3223+00 41.99 44.99 44.99 39.67 3275+00 45.13 48.13 48.13 42.21 3224+00 42.09 45.09 45.09 39.76 3276+00 45.34 48.34 48.34 42.36 3225+00 42.20 45.20 45.20 39.85 3277+00 45.61 48.61 48.61 42.58 3226+00 42.30 45.30 45.30 39.94 3278+00 45.68 48.68 48.68 42.64 3227+00 42.41 45.41 45.41 40.03 3279+00 45.75 48.75 48.75 42.69 3228+00 42.46 45.46 45.46 40.07 3280+00 45.81 48.81 48.81 42.74 3229+00 42.47 45.47 45.47 40.09 3281+00 45.83 48.83 48.83 42.76 3230+00 42.49 45.49 45.49 40.12 3282+00 45.85 48.85 48.85 42.77 3231+00 42.50 45.50 45.50 40.14 3283+00 45.87 48.87 48.87 42.79 3232+00 42.52 45.52 45.52 40.16 3284+00 45.89 48.89 48.89 42.80 3233+00 42.54 45.54 45.54 40.20 3285+00 45.91 48.91 48.91 42.82 3234+00 42.58 45.58 45.58 40.26 3286+00 45.93 48.93 48.93 42.83 3235+00 42.61 45.61 45.61 40.32 3287+00 45.95 48.95 48.95 42.85 3236+00 42.64 45.64 45.64 40.37 3288+00 45.99 48.99 48.99 42.88 3237+00 42.69 45.69 45.69 40.43 3289+00 46.06 49.06 49.06 42.93 3238+00 42.75 45.75 45.75 40.50 3290+00 46.13 49.13 49.13 42.99 3239+00 42.82 45.82 45.82 40.57 3291+00 46.20 49.20 49.20 43.04 3240+00 42.88 45.88 45.88 40.63 3292+00 46.27 49.27 49.27 43.09 3241+00 43.04 46.04 46.04 40.77 3293+00 46.34 49.34 49.34 43.15 3242+00 42.84 45.84 45.84 40.65 3294+00 46.32 49.32 49.32 43.13 3243+00 42.99 45.99 45.99 40.74 3295+00 46.31 49.31 49.31 43.12 3244+00 43.14 46.14 46.14 40.84 3296+00 46.36 49.36 49.36 43.17 3245+00 43.29 46.29 46.29 40.93 3297+00 46.40 49.40 49.40 43.22 3246+00 43.45 46.45 46.45 41.03 3298+00 46.45 49.45 49.45 43.27 3247+00 43.50 46.50 46.50 41.07 3299+00 46.49 49.49 49.49 43.32 3248+00 43.55 46.55 46.55 41.11 3300+00 46.56 49.56 49.56 43.38 3249+00 43.60 46.60 46.60 41.15 3301+00 46.65 49.65 49.65 43.44 3250+00 43.65 46.65 46.65 41.19 3302+00 46.74 49.74 49.74 43.51 3251+00 43.66 46.66 46.66 41.20 3303+00 46.82 49.82 49.82 43.57 3252+00 43.64 46.64 46.64 41.18 3304+00 46.91 49.91 49.91 43.63 3253+00 43.62 46.62 46.62 41.17 3305+00 46.95 49.95 49.95 43.67 3254+00 43.60 46.60 46.60 41.15 3306+00 46.98 49.98 49.98 43.70 3255+00 43.60 46.60 46.60 41.15 3307+00 47.01 50.01 50.01 43.73 3256+00 43.63 46.63 46.63 41.17 3308+00 47.04 50.04 50.04 43.76 3257+00 43.66 46.66 46.66 41.18 3309+00 47.08 50.08 50.08 43.79 3258+00 43.69 46.69 46.69 41.20 3310+00 47.11 50.11 50.11 43.82 3259+00 43.73 46.73 46.73 41.22 3311+00 47.15 50.15 50.15 43.85 D-4
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3312+00 47.19 50.19 50.19 43.88 3364+00 48.70 51.70 51.70 45.16 3313+00 47.23 50.23 50.23 43.92 3365+00 48.67 51.67 51.67 45.15 3314+00 47.27 50.27 50.27 43.95 3366+00 48.64 51.64 51.64 45.13 3315+00 47.31 50.31 50.31 43.98 3367+00 48.61 51.61 51.61 45.12 3316+00 47.32 50.32 50.32 43.99 3368+00 48.58 51.58 51.58 45.10 3317+00 47.33 50.33 50.33 43.99 3369+00 48.55 51.55 51.55 45.08 3318+00 47.33 50.33 50.33 44.00 3370+00 48.52 51.52 51.52 45.07 3319+00 47.34 50.34 50.34 44.01 3371+00 48.49 51.49 51.49 45.05 3320+00 47.35 50.35 50.35 44.01 3372+00 48.47 51.47 51.47 45.03 3321+00 47.34 50.34 50.34 44.01 3373+00 48.44 51.44 51.44 45.02 3322+00 47.33 50.33 50.33 44.00 3374+00 48.42 51.42 51.42 45.02 3323+00 47.32 50.32 50.32 44.00 3375+00 48.54 51.54 51.54 45.11 3324+00 47.31 50.31 50.31 43.99 3376+00 48.59 51.59 51.59 45.13 3325+00 47.30 50.30 50.30 43.99 3377+00 48.67 51.67 51.67 45.20 3326+00 47.30 50.30 50.30 43.98 3378+00 48.75 51.75 51.75 45.27 3327+00 47.32 50.32 50.32 44.00 3379+00 48.83 51.83 51.83 45.35 3328+00 47.33 50.33 50.33 44.01 3380+00 48.91 51.91 51.91 45.42 3329+00 47.35 50.35 50.35 44.03 3381+00 48.99 51.99 51.99 45.49 3330+00 47.36 50.36 50.36 44.04 3382+00 49.07 52.07 52.07 45.56 3331+00 47.36 50.36 50.36 44.04 3383+00 49.15 52.15 52.15 45.63 3332+00 47.36 50.36 50.36 44.05 3384+00 49.23 52.23 52.23 45.70 3333+00 47.37 50.37 50.37 44.05 3385+00 49.30 52.30 52.30 45.77 3334+00 47.39 50.39 50.39 44.07 3386+00 49.34 52.34 52.34 45.82 3335+00 47.42 50.42 50.42 44.10 3387+00 49.39 52.39 52.39 45.87 3336+00 47.45 50.45 50.45 44.13 3388+00 49.43 52.43 52.43 45.92 3337+00 47.49 50.49 50.49 44.16 3389+00 49.48 52.48 52.48 45.97 3338+00 47.52 50.52 50.52 44.19 3390+00 49.52 52.52 52.52 46.02 3339+00 47.50 50.50 50.50 44.17 3391+00 49.57 52.57 52.57 46.07 3340+00 47.47 50.47 50.47 44.15 3392+00 49.62 52.62 52.62 46.12 3341+00 47.45 50.45 50.45 44.14 3393+00 49.66 52.66 52.66 46.17 3342+00 47.42 50.42 50.42 44.12 3394+00 49.71 52.71 52.71 46.22 3343+00 47.41 50.41 50.41 44.11 3395+00 49.79 52.79 52.79 46.29 3344+00 47.47 50.47 50.47 44.16 3396+00 49.90 52.90 52.90 46.39 3345+00 47.53 50.53 50.53 44.21 3397+00 50.01 53.01 53.01 46.48 3346+00 47.58 50.58 50.58 44.26 3398+00 50.12 53.12 53.12 46.57 3347+00 47.64 50.64 50.64 44.31 3399+00 50.22 53.22 53.22 46.66 3348+00 47.70 50.70 50.70 44.36 3400+00 50.26 53.26 53.26 46.69 3349+00 47.76 50.76 50.76 44.41 3401+00 50.30 53.30 53.30 46.72 3350+00 47.81 50.81 50.81 44.46 3402+00 50.34 53.34 53.34 46.75 3351+00 47.86 50.86 50.86 44.50 3403+00 50.38 53.38 53.38 46.78 3352+00 47.92 50.92 50.92 44.55 3404+00 50.40 53.40 53.40 46.82 3353+00 47.97 50.97 50.97 44.59 3405+00 50.42 53.42 53.42 46.87 3354+00 48.04 51.04 51.04 44.65 3406+00 50.44 53.44 53.44 46.91 3355+00 48.11 51.11 51.11 44.70 3407+00 50.45 53.45 53.45 46.96 3356+00 48.18 51.18 51.18 44.75 3408+00 50.51 53.51 53.51 47.02 3357+00 48.25 51.25 51.25 44.81 3409+00 50.58 53.58 53.58 47.09 3358+00 48.32 51.32 51.32 44.86 3410+00 50.65 53.65 53.65 47.16 3359+00 48.39 51.39 51.39 44.92 3411+00 50.72 53.72 53.72 47.22 3360+00 48.46 51.46 51.46 44.97 3412+00 50.79 53.79 53.79 47.28 3361+00 48.53 51.53 51.53 45.02 3413+00 50.85 53.85 53.85 47.34 3362+00 48.59 51.59 51.59 45.08 3414+00 50.91 53.91 53.91 47.40 3363+00 48.66 51.66 51.66 45.13 3415+00 50.96 53.96 53.96 47.46 D-5
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3416+00 51.02 54.02 54.02 47.51 3468+00 53.04 56.04 56.04 49.16 3417+00 51.08 54.08 54.08 47.55 3469+00 53.03 56.03 56.03 49.15 3418+00 51.13 54.13 54.13 47.59 3470+00 53.02 56.02 56.02 49.15 3419+00 51.18 54.18 54.18 47.63 3471+00 53.01 56.01 56.01 49.15 3420+00 51.23 54.23 54.23 47.67 3472+00 53.00 56.00 56.00 49.14 3421+00 51.30 54.30 54.30 47.72 3473+00 52.99 55.99 55.99 49.14 3422+00 51.38 54.38 54.38 47.77 3474+00 52.99 55.99 55.99 49.14 3423+00 51.45 54.45 54.45 47.82 3475+00 52.99 55.99 55.99 49.14 3424+00 51.53 54.53 54.53 47.87 3476+00 52.98 55.98 55.98 49.14 3425+00 51.63 54.63 54.63 47.95 3477+00 52.98 55.98 55.98 49.14 3426+00 51.77 54.77 54.77 48.05 3478+00 52.98 55.98 55.98 49.14 3427+00 51.90 54.90 54.90 48.15 3479+00 52.98 55.98 55.98 49.15 3428+00 52.04 55.04 55.04 48.26 3480+00 52.98 55.98 55.98 49.15 3429+00 52.13 55.13 55.13 48.33 3481+00 52.97 55.97 55.97 49.15 3430+00 52.14 55.14 55.14 48.33 3482+00 52.97 55.97 55.97 49.15 3431+00 52.14 55.14 55.14 48.33 3483+00 52.97 55.97 55.97 49.15 3432+00 52.17 55.17 55.17 48.35 3484+00 52.98 55.98 55.98 49.16 3433+00 52.21 55.21 55.21 48.39 3485+00 52.99 55.99 55.99 49.17 3434+00 52.26 55.26 55.26 48.43 3486+00 53.01 56.01 56.01 49.18 3435+00 52.30 55.30 55.30 48.47 3487+00 53.02 56.02 56.02 49.20 3436+00 52.34 55.34 55.34 48.50 3488+00 53.03 56.03 56.03 49.21 3437+00 52.39 55.39 55.39 48.54 3489+00 53.04 56.04 56.04 49.22 3438+00 52.43 55.43 55.43 48.58 3490+00 53.06 56.06 56.06 49.23 3439+00 52.47 55.47 55.47 48.62 3491+00 53.07 56.07 56.07 49.24 3440+00 52.52 55.52 55.52 48.66 3492+00 53.08 56.08 56.08 49.26 3441+00 52.56 55.56 55.56 48.69 3493+00 53.10 56.10 56.10 49.27 3442+00 52.58 55.58 55.58 48.71 3494+00 53.12 56.12 56.12 49.27 3443+00 52.60 55.60 55.60 48.73 3495+00 53.14 56.14 56.14 49.28 3444+00 52.62 55.62 55.62 48.75 3496+00 53.17 56.17 56.17 49.29 3445+00 52.64 55.64 55.64 48.77 3497+00 53.19 56.19 56.19 49.29 3446+00 52.66 55.66 55.66 48.79 3498+00 53.21 56.21 56.21 49.30 3447+00 52.68 55.68 55.68 48.80 3499+00 53.24 56.24 56.24 49.31 3448+00 52.70 55.70 55.70 48.82 3500+00 53.26 56.26 56.26 49.31 3449+00 52.72 55.72 55.72 48.84 3501+00 53.34 56.34 56.34 49.40 3450+00 52.73 55.73 55.73 48.86 3502+00 53.46 56.46 56.46 49.54 3451+00 52.75 55.75 55.75 48.87 3503+00 53.58 56.58 56.58 49.68 3452+00 52.77 55.77 55.77 48.89 3504+00 53.70 56.70 56.70 49.82 3453+00 52.79 55.79 55.79 48.91 3505+00 53.72 56.72 56.72 49.86 3454+00 52.81 55.81 55.81 48.93 3506+00 53.68 56.68 56.68 49.84 3455+00 52.83 55.83 55.83 48.95 3507+00 53.64 56.64 56.64 49.83 3456+00 52.86 55.86 55.86 48.97 3508+00 53.61 56.61 56.61 49.81 3457+00 52.88 55.88 55.88 48.99 3509+00 53.73 56.73 56.73 49.91 3458+00 52.90 55.90 55.90 49.01 3510+00 53.94 56.94 56.94 50.06 3459+00 52.92 55.92 55.92 49.04 3511+00 54.15 57.15 57.15 50.22 3460+00 52.95 55.95 55.95 49.06 3512+00 54.34 57.34 57.34 50.38 3461+00 52.97 55.97 55.97 49.08 3513+00 54.51 57.51 57.51 50.55 3462+00 52.99 55.99 55.99 49.10 3514+00 54.67 57.67 57.67 50.72 3463+00 53.01 56.01 56.01 49.12 3515+00 54.80 57.80 57.80 50.85 3464+00 53.04 56.04 56.04 49.14 3516+00 54.85 57.85 57.85 50.89 3465+00 53.06 56.06 56.06 49.16 3517+00 54.90 57.90 57.90 50.94 3466+00 53.06 56.06 56.06 49.17 3518+00 55.04 58.04 58.04 51.09 3467+00 53.05 56.05 56.05 49.16 3519+00 55.15 58.15 58.15 51.21 D-6
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3520+00 55.21 58.21 58.21 51.29 3552+00 57.20 60.20 60.20 54.90 3521+00 55.28 58.28 58.28 51.38 3553+00 57.29 60.29 60.29 55.03 3522+00 55.35 58.35 58.35 51.45 3554+00 57.38 60.38 60.38 55.17 3523+00 55.40 58.40 58.40 51.52 3555+00 57.47 60.47 60.47 55.30 3524+00 55.47 58.47 58.47 51.60 3556+00 57.56 60.56 60.56 55.44 3525+00 55.47 58.47 58.47 51.63 3557+00 57.64 60.64 60.64 55.57 3526+00 55.49 58.49 58.49 51.66 3558+00 57.74 60.74 60.74 55.68 3527+00 55.52 58.52 58.52 51.70 3559+00 57.85 60.85 60.85 55.79 3528+00 55.60 58.60 58.60 51.81 3560+00 57.95 60.95 60.95 55.90 3529+00 55.69 58.69 58.69 51.94 3561+00 58.05 61.05 61.05 56.01 3530+00 55.82 58.82 58.82 52.15 3562+00 58.15 61.15 61.15 56.12 3531+00 55.92 58.92 58.92 52.31 3563+00 58.21 61.21 61.21 56.20 3532+00 56.00 59.00 59.00 52.41 3564+00 58.24 61.24 61.24 56.26 3533+00 56.09 59.09 59.09 52.52 3565+00 58.26 61.26 61.26 56.32 3534+00 56.20 59.20 59.20 52.65 3566+00 58.34 61.34 61.34 56.42 3535+00 56.30 59.30 59.30 52.78 3567+00 58.49 61.49 61.49 56.58 3536+00 56.35 59.35 59.35 52.85 3568+00 58.64 61.64 61.64 56.74 3537+00 56.40 59.40 59.40 52.92 3569+00 58.79 61.79 61.79 56.89 3538+00 56.47 59.47 59.47 53.03 3570+00 58.95 61.95 61.95 57.03 3539+00 56.54 59.54 59.54 53.14 3571+00 59.11 62.11 62.11 57.17 3540+00 56.62 59.62 59.62 53.24 3572+00 59.27 62.27 62.27 57.31 3541+00 56.66 59.66 59.66 53.32 3573+00 59.43 62.43 62.43 57.45 3542+00 56.69 59.69 59.69 53.38 3574+00 59.57 62.57 62.57 57.58 3543+00 56.71 59.71 59.71 53.44 3575+00 59.65 62.65 62.65 57.69 3544+00 56.74 59.74 59.74 53.52 3576+00 59.73 62.73 62.73 57.79 3545+00 56.76 59.76 59.76 53.63 3577+00 59.82 62.82 62.82 57.90 3546+00 56.78 59.78 59.78 53.75 3578+00 59.90 62.90 62.90 58.00 3547+00 56.80 59.80 59.80 53.86 3579+00 59.98 62.98 62.98 58.11 3548+00 56.76 59.76 59.76 53.99 3580+00 60.14 63.14 63.14 58.21 3549+00 56.73 59.73 59.73 54.14 3581+00 60.29 63.29 63.29 58.31 3550+00 56.87 59.87 59.87 54.39 3582+00 60.45 63.45 63.45 58.42 3551+00 57.04 60.04 60.04 54.66 3582+80 60.58 63.58 63.58 58.50 D-7
Table D-2. ULDC Hydraulic Parameter Profiles, Arcade Creek South Levee Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
4000+00 37.10 40.10 40.10 4037+00 37.77 40.77 40.77 4074+00 38.48 41.48 41.48 4001+00 37.44 40.44 40.44 4038+00 37.78 40.78 40.78 4075+00 38.50 41.50 41.50 4002+00 37.53 40.53 40.53 4039+00 37.78 40.78 40.78 4076+00 38.52 41.52 41.52 4003+00 37.63 40.63 40.63 4040+00 37.78 40.78 40.78 4077+00 38.54 41.54 41.54 4004+00 37.64 40.64 40.64 4041+00 37.78 40.78 40.78 4078+00 38.56 41.56 41.56 4005+00 37.64 40.64 40.64 4042+00 37.78 40.78 40.78 4079+00 38.58 41.58 41.58 4006+00 37.65 40.65 40.65 4043+00 37.79 40.79 40.79 4080+00 38.60 41.60 41.60 4007+00 37.65 40.65 40.65 4044+00 37.79 40.79 40.79 4081+00 38.64 41.64 41.64 4008+00 37.66 40.66 40.66 4045+00 37.79 40.79 40.79 4082+00 38.67 41.67 41.67 4009+00 37.66 40.66 40.66 4046+00 37.79 40.79 40.79 4083+00 38.70 41.70 41.70 4010+00 37.66 40.66 40.66 4047+00 37.80 40.80 40.80 4084+00 38.74 41.74 41.74 4011+00 37.67 40.67 40.67 4048+00 37.80 40.80 40.80 4085+00 38.80 41.80 41.80 4012+00 37.67 40.67 40.67 4049+00 37.81 40.81 40.81 4086+00 38.87 41.87 41.87 4013+00 37.67 40.67 40.67 4050+00 37.81 40.81 40.81 4087+00 38.95 41.95 41.95 4014+00 37.67 40.67 40.67 4051+00 37.82 40.82 40.82 4088+00 39.02 42.02 42.02 4015+00 37.67 40.67 40.67 4052+00 37.82 40.82 40.82 4089+00 39.10 42.10 42.10 4016+00 37.68 40.68 40.68 4053+00 37.83 40.83 40.83 4090+00 39.16 42.16 42.16 4017+00 37.68 40.68 40.68 4054+00 37.85 40.85 40.85 4091+00 39.22 42.22 42.22 4018+00 37.68 40.68 40.68 4055+00 37.86 40.86 40.86 4092+00 39.28 42.28 42.28 4019+00 37.68 40.68 40.68 4056+00 37.88 40.88 40.88 4093+00 39.33 42.33 42.33 4020+00 37.68 40.68 40.68 4057+00 37.89 40.89 40.89 4094+00 39.39 42.39 42.38 4021+00 37.69 40.69 40.69 4058+00 37.90 40.90 40.90 4095+00 39.43 42.43 42.38 4022+00 37.69 40.69 40.69 4059+00 37.91 40.91 40.91 4096+00 39.46 42.46 42.38 4023+00 37.69 40.69 40.69 4060+00 37.92 40.92 40.92 4097+00 39.48 42.48 42.38 4024+00 37.69 40.69 40.69 4061+00 37.92 40.92 40.92 4098+00 39.51 42.51 42.38 4025+00 37.70 40.70 40.70 4062+00 37.93 40.93 40.93 4099+00 39.54 42.54 42.39 4026+00 37.70 40.70 40.70 4063+00 37.93 40.93 40.93 4100+00 39.70 42.70 42.41 4027+00 37.71 40.71 40.71 4064+00 37.92 40.92 40.92 4101+00 39.96 42.96 42.44 4028+00 37.71 40.71 40.71 4065+00 38.07 41.07 41.07 4102+00 40.21 43.21 42.47 4029+00 37.71 40.71 40.71 4066+00 38.12 41.12 41.12 4103+00 40.47 43.47 42.50 4030+00 37.72 40.72 40.72 4067+00 38.13 41.13 41.13 4104+00 40.73 43.73 42.54 4031+00 37.74 40.74 40.74 4068+00 38.14 41.14 41.14 4105+00 40.95 43.95 42.57 4032+00 37.74 40.74 40.74 4069+00 38.34 41.34 41.34 4106+00 41.12 44.12 42.60 4033+00 37.74 40.74 40.74 4070+00 38.37 41.37 41.37 4107+00 41.30 44.30 42.63 4034+00 37.74 40.74 40.74 4071+00 38.39 41.39 41.39 4108+00 41.47 44.47 42.66 4035+00 37.74 40.74 40.74 4072+00 38.42 41.42 41.42 4109+00 41.65 44.65 42.69 4036+00 37.73 40.73 40.73 4073+00 38.45 41.45 41.45 4110+00 41.82 44.82 42.73 D-8
Table D-3. ULDC Hydraulic Parameter Profiles, NEMDC East Levee Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
2986+49 35.64 38.64 38.64 3020+00 36.29 39.29 39.29
2987+00 35.65 38.65 38.65 3021+00 36.32 39.32 39.32
2988+00 35.69 38.69 38.69 3022+00 36.39 39.39 39.39
2989+00 35.72 38.72 38.72 3023+00 36.44 39.44 39.44
2990+00 35.73 38.73 38.73 3024+00 36.46 39.46 39.46
2991+00 35.74 38.74 38.74 3025+00 36.49 39.49 39.49
2992+00 35.76 38.76 38.76 3026+00 36.52 39.52 39.52
2993+00 35.77 38.77 38.77 3027+00 36.55 39.55 39.55
2994+00 35.78 38.78 38.78 3028+00 36.57 39.57 39.57
2995+00 35.80 38.80 38.80 3029+00 36.60 39.60 39.60
2996+00 35.81 38.81 38.81 3030+00 36.63 39.63 39.63
2997+00 35.82 38.82 38.82 3031+00 36.65 39.65 39.65
2998+00 35.84 38.84 38.84 3032+00 36.67 39.67 39.67
2999+00 35.85 38.85 38.85 3033+00 36.70 39.70 39.70
3000+00 35.86 38.86 38.86 3034+00 36.72 39.72 39.72
3001+00 35.92 38.92 38.92 3035+00 36.74 39.74 39.74
3002+00 35.93 38.93 38.93 3036+00 36.77 39.77 39.77
3003+00 35.94 38.94 38.94 3037+00 36.79 39.79 39.79
3004+00 35.95 38.95 38.95 3038+00 36.82 39.82 39.82
3005+00 35.96 38.96 38.96 3039+00 36.85 39.85 39.85
3006+00 35.96 38.96 38.96 3040+00 36.87 39.87 39.87
3007+00 35.97 38.97 38.97 3041+00 36.90 39.90 39.90
3008+00 35.99 38.99 38.99 3042+00 36.93 39.93 39.93
3009+00 36.02 39.02 39.02 3043+00 36.95 39.95 39.95
3010+00 36.05 39.05 39.05 3044+00 36.98 39.98 39.98
3011+00 36.08 39.08 39.08 3045+00 36.99 39.99 39.99
3012+00 36.11 39.11 39.11 3046+00 37.01 40.01 40.01
3013+00 36.14 39.14 39.14 3047+00 37.03 40.03 40.03
3014+00 36.17 39.17 39.17 3048+00 37.05 40.05 40.05
3015+00 36.20 39.20 39.20 3049+00 37.06 40.06 40.06
3016+00 36.22 39.22 39.22 3050+00 37.08 40.08 40.08
3017+00 36.24 39.24 39.24 3051+00 37.10 40.10 40.10
3018+00 36.26 39.26 39.26 3051+61 37.10 40.10 40.10
3019+00 36.28 39.28 39.28
Appendix D.

American River North ULDC
Due Diligence, Geotech - AECOM
Final REPORT
July 22, 2024
North Area Streams
ULDC Geotechnical Findings For
NEMDC East Levee
Stations 3029+00 to 3051+00
And
Arcade Creek South Levee
Stations 4000+00 to 4110+00
Prepared For
Sacramento Area Flood Control Agency
Only the Client or its Designated Representatives May Use this Document and Only for the Specific Project for Which
This Geotechnical Findings Report is Prepared
July 22, 2024
Mr. Dan Tibbitts, PE
Director of Engineering
Sacramento Area Flood Control Agency
1325 J Street, Suite 1700
Sacramento, CA 95814
Subject: ULDC Geotechnical Findings Report
NEMDC East Levee - Stations 3029+00 to 3051+00
Arcade Creek South Levee - Stations 4000+00 to 4110+00
Dear Mr. Tibbitts:

Enclosed please find AECOM’s Geotechnical Findings Report containing conclusions regarding whether the NEMDC east and Arcade Creek south levees conform to geotechnical-related criteria in the following sections of the State of California, Department of Water Resources, Urban Levee Design Criteria (ULDC) (DWR, 2012), which is required for certification:

Section 7.3, Soil Sampling, Testing, and Logging
Section 7.4, Slope Stability for Intermittently Loaded Levees Section 7.5, Underseepage for Intermittently Loaded Levees Section 7.7 Seismic Vulnerability
Section 7.8 Levee Geometry
Section 7.9 Interfaces and Transitions
Section 7.10 Erosion
Section 7.13 Penetrations
Section 7.14 Floodwalls, Retaining Walls, and Closure Structures Note that Sections 7.7, 7.8, 7.10, and 7.13 are also included in compliance reports being prepared by other consultants. The information being provided in this report is geotechnical-related information supporting the other reports.

AECOM completed the geotechnical evaluation for the Sacramento Area Flood Control Agency (SAFCA). The evaluation examined available subsurface and soil characterization data, reports, design evaluations, record drawings, and other relevant documentation for the project prepared by AECOM and other consultants to SAFCA. No new investigations or geotechnical analyses were performed. Geotechnical analyses and results were compared against current standards of practice for levees contained in USACE and other agency standards, and the ULDC.

If you have questions regarding this report, please contact the undersigned.

Sincerely,
Richard Millet, PE, GE
Senior Geotechnical Engineer
Cc: Mr. Pro Mitra, PE/MBK Engineers ([email protected]) Ms. Becky Money, PE/GE/MBK Engineers ([email protected]) ULDC Geotechnical Findings NEMDC Arcade South i July 22, 2024

TABLE OF CONTENTS

1.0 Introduction .......................................................................................................... 1-1

1.1 North Area Streams Background ................................................................. 1-1

1.2 In-ground pools ........................................................................................... 1-2

2.0 Geotechnical Review ........................................................................................... 2-1

2.1 Data, Criteria, and Methods ......................................................................... 2-1

2.1.1 Data Review ................................................................................... 2-1

2.1.2 Stationing and Reaches .................................................................. 2-1

2.1.3 Documents Reviewed ..................................................................... 2-1

2.1.4 Applicable Criteria ........................................................................... 2-2

2.1.5 Critical Levee Sections ................................................................... 2-2

2.1.6 Levee Height and Hydraulic Head .................................................. 2-3

2.1.7 Design Water Surface Elevations ................................................... 2-3

2.2 ULDC Section 7.3 Soil Sampling, Testing, and Logging .............................. 2-4

2.2.1 Subsurface investigations ............................................................... 2-5

2.2.1.1 Conclusion .........................................................................2-6

2.2.2 Sampling and Testing ...................................................................... 2-6

2.2.2.1 Conclusion .........................................................................2-6

2.3 ULDC Section 7.4 Slope Stability for Intermittently Loaded Levees ............ 2-7

2.3.1 Conclusion ...................................................................................... 2-8

2.4 ULDC Section 7.5 Underseepage ............................................................... 2-8

2.4.1 In-ground Pool Evaluation, Station ACSL 4060+00 ........................ 2-9

2.4.2 Conclusion ...................................................................................... 2-9

2.5 ULDC Section 7.7 Seismic Vulnerability ...................................................... 2-9

2.6 ULDC section 7.8 levee geometry ............................................................... 2-9

2.6.1 Conclusion .................................................................................... 2-10

2.7 ULDC Section 7.9 Interfaces and Transitions ............................................ 2-10

2.7.1 Toe Cutoff Wall Interface - Station 3029+00 ................................. 2-11

2.7.1.1 Conclusion ....................................................................... 2-11

2.7.2 Cutoff Wall Gap, NEMDC Station 3051+00 to ACSL Station 4001+85........................................................................................ 2-11

2.7.2.1 Conclusion .......................................................................2-12

2.7.3 Slurry Cutoff Wall Interface, ACSL Station 4013+00 ..................... 2-13

2.7.3.1 Conclusion .......................................................................2-13

2.7.4 Slurry Cutoff Wall Interface, ACSL Station 4031+18 ..................... 2-13

2.7.4.1 Conclusion .......................................................................2-14

2.7.5 Slurry Cutoff Wall Gap, ACSL Stations 4065+20 to 4067+00 ....... 2-14

2.7.5.1 Conclusion .......................................................................2-14

2.7.6 Slurry Cutoff Wall Interface, ACSL Station 4083+21 ..................... 2-14

2.7.6.1 Conclusion .......................................................................2-15

2.7.7 ACSL End Transition at Marysville Boulevard ............................... 2-15

2.7.7.1 Conclusion .......................................................................2-15 ULDC Geotechnical Findings NEMDC Arcade South ii July 22, 2024

2.7.8 Arcade Creek South Levee Transitions at Road Crossings .......... 2-15

2.7.8.1 Conclusion .......................................................................2-16

2.8 ULDC Section 7.10 Erosion ....................................................................... 2-16

2.8.1 NEMDC East Levee ...................................................................... 2-16

2.8.2 Arcade Creek South Levee ........................................................... 2-16

2.9 ULDC Section 7.13 Penetrations ............................................................... 2-17

2.9.1 Review of Penetration Data .......................................................... 2-17

2.9.2 Drainage Pipe Reconstruction, Station 4076+60 .......................... 2-18

2.9.3 AT&T Duct Bank, Station 4067+60 ............................................... 2-18

2.10 ULDC Section 7.14 Floodwalls, Retaining Walls, and Closure Structures . 2-18

2.10.1 Existing Flood Walls and Curbs .................................................... 2-19

2.10.2 Conclusion .................................................................................... 2-19

3.0 Arcade Creek South Levee and NEMDC East Levee Study Area Summary of Results ................................................................................................................. 3-1

4.0 Limitations ............................................................................................................ 4-1

5.0 References .......................................................................................................... 5-1 TABLES
Table 2-1 Levee Reaches and Stationing ............................................................... 2-1 Table 2-2 Available Critical Levee Cross Sections.................................................. 2-3 Table 2-3 Subsurface Explorations – NEMDC ........................................................ 2-5 Table 2-4 Subsurface Explorations – ACSL ............................................................ 2-5 Table 2-5 Minimum ULDC Safety Factors for Slope Stability .................................. 2-7 Table 2-6 Allowable Exit Gradients ......................................................................... 2-8 Table 2-7 Interfaces, Transitions, and Gaps ......................................................... 2-10 Table 2-8 Gap Seepage Analysis Results ............................................................ 2-12 Table 3-1 Summary of Results................................................................................ 3-1

FIGURES
Figure 1 AECOM Levees Evaluated

APPENDICES
A 200-Year Design Water Surface Elevations
B Geotechnical Evaluation Results Summary
C UPRR Stoplog Closure Arcade Creek South
D Levee Geometry Cross Section Evaluation
E AECOM Completion Report - Waterside Fill Replacement Station 4067+60 ULDC Geotechnical Findings NEMDC Arcade South iii July 22, 2024

ACRONYMS AND ABBREVIATIONS
AAR Alternative Analysis Report
AECOM AECOM Technical Services, Inc.

ACSL Arcade Creek South Levee
CPT Cone Penetrometer
DWR California Department of Water Resources
DWSE Design Water Surface Elevation
ft feet
GDR Geotechnical Data Report
GERPD Geotechnical Engineering Report for Project Design HTOL hydraulic top of levee
MBK MBK Engineers
NAS North Area Streams
NEMDC Natomas East Main Drainage Canal East Levee
PBI Peterson Brustad, Inc.
pcf pounds per cubic feet
PIRs Problem Identification Reports
SCCB slag cement-cement-bentonite
SAFCA Sacramento Area Flood Control Agency
SRFCP Sacramento River Flood Control Project
ULDC Urban Levee Design Criteria
UPRR Union Pacific Railroad
USACE U.S. Army Corps of Engineers
WSE Water Surface Elevation
ULDC Geotechnical Findings NEMDC Arcade South 1-1 July 22, 2024

1.0 INTRODUCTION
This geotechnical finding report documents AECOM’s (formerly URS’s) evaluation of the levees listed below and shown in Figure 1. These levees have a combined length of approximately 2.5 miles and are a part of the North Area Streams (NAS) levee system.  Natomas East Main Drainage Canal east levee (NEMDC), Stations 3029+00 to 3051+00
 Arcade Creek south levee (ACSL), Stations 4000+00 to 4110+00 AECOM’s evaluation was conducted at the request of the Sacramento Area Flood Control Agency (SAFCA) to ascertain levee compliance with the geotechnical criteria specified in the following eight sections of the California Department of Water Resources (DWR) Urban Levee Design Criteria (ULDC) (DWR, 2012):
 Section 7.3 Soil Sampling, Testing, and Logging
 Section 7.4 Slope Stability for Intermittently Loaded Levees  Section 7.5 Underseepage for Intermittently Loaded Levees  Section 7.7 Seismic Vulnerability
 Section 7.8 Levee Geometry
 Section 7.9 Interfaces and Transitions
 Section 7.10 Erosion
 Section 7.13 Penetrations
 Section 7.14 Floodwalls, Retaining Walls, and Closure Structures Note that Sections 7.7, 7.8, 7.10, and 7.13 are also included in compliance reports being prepared by other consultants. The information being provided for these sections in this report is geotechnical-related information supporting the other reports. AECOM’s findings and conclusions presented herein reflect the current criteria contained in the 2012 version of the ULDC. Findings and conclusions may change if the ULDC criteria is changed.

1.1 NORTH AREA STREAMS BACKGROUND
As shown in Figure 1, the NAS levee system includes about 12 miles of levee along the east bank of NEMDC, the north and south banks of Dry/Robla Creek, and the north and south banks of Arcade Creek. These levees, which includes the ones covered in this report, were originally constructed in the 1930s and 1950s as components of the Sacramento River Flood Control Project (SRFCP) by the U.S. Army Corps of Engineers (USACE) as authorized by Congress under the Flood Control Act of 1917, including subsequent amendments.

After completing certain upgrades to conform these levees to SRFCP requirements, the operation and maintenance responsibility was transferred to the State of California. The Central Valley Flood Protection Board is the non-Federal project sponsor; the American River Flood Control District is responsible for maintaining the levees. SAFCA is responsible for implementing levee improvement projects as the managing agency for these levees.

ULDC Geotechnical Findings NEMDC Arcade South 1-2 July 22, 2024 Beginning in the 1990’s SAFCA implemented various improvement projects within the NAS levee system. Improvements typically included crest raises and widening, waterside slope blanket construction, landside drainage improvements, addition of waterside flood walls to existing levee crests, and other work. The most recent improvement project, completed in 2019, included construction of centerline and toe slurry cutoff walls, reconstructing waterside slopes, and other related work to remediate seepage and stability deficiencies identified in problem identification reports (PIRs).

Also, gravity storm drainage pipelines and pump station discharge pipelines at City of Sacramento interior drainage pump stations were upgraded to conform to ULDC and other applicable requirements. More detailed description of completed levee improvement projects and sources for available site investigations, engineering analyses, record drawings, and other supporting documentation can be found in the documents referenced in Section 2.1.3.

1.2 IN-GROUND POOLS
In-ground pools on the landside of the levee can present a seepage-related failure risk, particularly if they are located close to the levee toe. From site reconnaissance, topographic surveys, and aerial photography, there is only one in-ground pool located along ACSL at Station 4060+00 that requires evaluation. The pool location is identified on Figure 1. The seepage analysis for the pool is provided in Section 2.4.1.

ULDC Geotechnical Findings NEMDC Arcade South 2-1 July 22, 2024

2.0 GEOTECHNICAL REVIEW

2.1 DATA, CRITERIA, AND METHODS

2.1.1 Data Review
AECOM’s geotechnical review involved examining the site investigations, engineering analyses, construction records, and other information contained in the reports cited in Section 2.1.3. AECOM believes the available information is adequate to arrive at conclusions regarding levee compliance with the ULDC criteria. Further site investigations or engineering analyses are not considered necessary to complete the compliance review. Refer to Section 2.2.1 for the evaluation of the adequacy of available site investigation data.

2.1.2 Stationing and Reaches
Historic centerline crown stations along the NEMDC and ACSL are used in this report to identify site investigation and geotechnical analysis locations, and the locations of interfaces, transitions, and other levee features described herein. To complete the geotechnical analyses described in the reference reports listed in Section 2.1.3, the levees were subdivided into reaches. Reach limits were selected so that the physical and geotechnical characteristics within the reach were consistent, allowing geotechnical evaluations using one or more critical analytic cross sections. In the reference reports, site characterizations of the levees and analysis results are presented by reach as well as by station. Table 2-1 shows the reach identifier names used in the reference reports and associated reach station limits. Figure 1 also shows the reach locations and station limits.

Table 2-1 Levee Reaches and Stationing
NEMDC East Levee
Stations 3029+00 to 3051+00
ACSL
Stations 4000+00 to 4110+00
Station Limits
(feet)
Reach Station Limits
(feet)
Reach
3029+00 to 3034+00 NE-1 4000+00 to 4013+00 ARS-1
3034+00 to 3051+00 NE-2 4013+00 to 4031+18 ARS-2
- - 4031+18 to 4068+45 ARS-3
- - 4068+45 to 4083+21 ARS-4
- - 4083+21 to 4110+00 ARS-5

2.1.3 Documents Reviewed
To assess compliance with the ULDC criteria, AECOM reviewed the following reports that contained relevant supporting data and geotechnical analyses:
 AECOM, 2016. North Area Streams Levee Improvement Project, Final Geotechnical Engineering Report for Project Design (GERPD)  AECOM, 2020. SAFCA North Area Streams Levee Improvement Project, NEMDC East, Arcade Creek North, and Arcade Creek South Record Drawings ULDC Geotechnical Findings NEMDC Arcade South 2-2 July 22, 2024  MBK Engineers, 2014. Technical Memorandum, 1/10, 1/200, 1/500 AEP Water Surface Elevations for SAFCA Levee Certification Reaches. April  MBK Engineers, 2024. Updated ULDC Water Surface Elevations, Arcade Creek South Levee and NEMDC East Levee. February 9, 2024
 Peterson Brustad, Inc (PBI), 2019. Record Drawings, SAFCA NAS, Miscellaneous Improvements
 Spink, 1996. Arcade Creek Unit 1B Levee Improvement, Record Drawings  Spink, 1996. NEMDC Levee Improvements Units 2B and 3B, Record Drawings  URS, 2014b. Geotechnical Data Report (GDR)
 URS, 2014d. Problem Identification Report (PIR)
 URS, 2014c. Alternatives Analysis Report (AAR)
 URS, 2015a. Geotechnical Data Report, Addendum 1
 URS, 2015b. Problem Identification Report, Addendum 1  URS, 2015e. Geotechnical Data Report, Addendum 2
 URS, 2016b. Geotechnical Data Report, Addendum 3
 United States Army Corps of Engineers, 2023. Supplement to the Standard Operations and Maintenance Manual, Sacramento River Flood Control Project, Unit No. 118-Part No. 2

2.1.4 Applicable Criteria
AECOM’s evaluations included comparing geotechnical analysis methods and calculated safety factors with recommended current practices provided in the following guidance documents:
 USACE EM 1110-2-1913 Design and Construction of Levees, April 30, 2000  USACE ETL 1110-2-569 Design Guidance for Levee Underseepage, May 1, 2005
 USACE EM 1110-2-1902, Engineering and Design, Slope Stability, October 2003  USACE EM 1110-2-1901, Engineering and Design, Seepage Analysis and Control for Dams. April 1993
 USACE SOP SPK EDG-03 Standard Operating Procedure 3, Geotechnical Levee Practice, May 2022
 Urban Levee Design Criteria (ULDC), State of California Department of Water Resources, May 2012

2.1.5 Critical Levee Sections
Table 2-2 list the available critical levee sections available from the reference geotechnical analysis documents that AECOM evaluated for ULDC compliance. Critical analytical sections represent worst case conditions within each levee reach for potential seepage, stability, and settlement considering stratigraphy, soil characteristics, topography, levee geometry, hydraulic head, and previous histories of poor performance. The GERPD and PIR documents provide additional background on selecting critical analytic sections.

ULDC Geotechnical Findings NEMDC Arcade South 2-3 July 22, 2024 Table 2-2 also compares levee crest and design water surface elevations used for critical section analyses in the reference documents with recently collected field verification survey data and design flood evaluation updates. Comparisons are described further in Section 2.1.6 and Section 2.1.7.

Table 2-2 Available Critical Levee Cross Sections
Critical Cross
Section Location
Landside
Toe El.
(feet)
Hydraulic
Head1
(feet)
Crest El. Comparisons
(feet)
Design Water Surface El. Comparison
(feet)
Used For
Analyses
2023
Survey
Check
200-Year
(feet)
(MBK, 2014)
Base Flood
El. (feet)
(MBK, 2024)
Difference
(feet)
NEMDC
Station 3032+00
Station 3038+00

22.0 19.6

17.4 19.9

43.2 43.3

42.87 43.53

39.4 39.5

36.67 36.82
-2.73
-2.68
Arcade Creek
Station 4001+10
Station 4008+00
Station 4022+00
Station 4040+00
Station 4063+57
Station 4079+00
Station 4090+00
Station 4094+00
Station 4102+30
Station 4108+00

24.0 24.1

25.9 28.6

34.1 34.3

35.6 36.3

39.5 37.7

14.9 15.9

13.1 11.5

6.0 6.2

4.2 3.7

1.1 3.6

44.0 44.5

44.8 44.1

45.0 43.63

43.13 43.53

43.73 44.23

43.7 44.6

44.5 44.53

44.82 43.52

43.04 43.35

43.80 44.12

38.9 40.0

39.0 40.1

40.1 40.5

39.8 40.0

40.6 41.3

37.44 37.66

37.69 37.78

37.93 38.58

39.16 39.39

40.29 41.47
-1.46
-2.34
-1.31
-2.32
-2.17
-1.92
-0.64
-0.61
-0.31

0.17 1. 200-year design water surface elevation hydraulic head relative to the landside toe.

2. All elevations (feet) based on North American Vertical Datum 1988.

3. Top of levee embankment excluding low concrete curb freeboard wall.

2.1.6 Levee Height and Hydraulic Head
Table 2-2, summarized from information in the tables in Appendix B, provides levee design characteristics for the critical sections evaluated, including crest elevations, landside toe elevations, and hydraulic head measured above the landside toe for the 200-year design water surface elevation (DWSE) (refer to Section 2.1.7). These characteristics are representative for the levee in the reaches they represent.

To confirm that the levee crest profiles have not changed since the analyses in the GERPD and PIR documents were performed, SAFCA authorized Psomas to survey elevations along the levee crown (Psomas, 2023). Table 2-2 provides a comparison of the 2023 crest elevation survey results with the elevations used for the analyses. There are no differences in elevation large enough to warrant updating any of the analyses.

2.1.7 Design Water Surface Elevations
The 200-year DWSE profile used in the geotechnical analyses of the levees was developed by MBK Engineers (MBK, 2014). The hydraulic top of levee (HTOL) water surface elevation, also included in the analyses, was typically set three feet above the DWSE.

ULDC Geotechnical Findings NEMDC Arcade South 2-4 July 22, 2024 To support the ULDC compliance reviews, MBK updated the DWSE and HTOL profile information (MBK, 2024). Appendix A provides the updated information by levee station in tabular form.

Table 2-2 compares the 2024 DWSE update with the corresponding values used for the geotechnical analyses at critical sections. In all but one case, the MBK 2024 updated water surface elevations are lower than the earlier MBK 2014 elevations. For the one, higher case (ACSL Sta. 4108+00), the difference is minor. Based on data in Table 2-2, there is no need to update geotechnical analyses.

2.2 ULDC SECTION 7.3 SOIL SAMPLING, TESTING, AND LOGGING AECOM evaluated the geotechnical field investigations and laboratory testing completed for the NEMDC and ACSL to provide conclusions regarding compliance with guidance provided in ULDC Section 7.3, Soil Sampling, Testing, and Logging, which is reproduced below:

ULDC (DWR, 2012) 7.3 requires soil sampling, testing, and logging per standard procedures prescribed in guidance documents, including the USACE Sacramento District’s Geotechnical Levee Practice Standard Operating Procedures (SPK SOP) (USACE, 2022) and DWR’s Division of Flood Management Soil and Rock Logging, Classification, Description and Presentation Manual (2009). This includes an evaluation of soil exploration quantity and location as outlined in the SPK SOP (USACE, 2022). Based on this document, explorations for a feasibility levee evaluation should be obtained at a spacing of approximately 1,000 feet along the levee crest. For preconstruction and design studies a spacing of approximately 500 feet along the waterside toe, levee crown, landside toe. Exploration depths should be a minimum of four times the levee height and extending to an appropriate stratum. Additional borings may be performed landward and waterward of the levee (100 to 500 ft away from the levee) to evaluate the distal seepage conditions. Explorations that did not meet the requirements outlined (e.g., explorations that were not drilled deep enough) above were not included.

The SPK SOP recommends a thorough evaluation of existing information as part of a levee evaluation program. This includes a review of original construction (if available), improvements, performance history, existing subsurface information, and regional and local geomorphology. The standard also recommends the use of cone penetrometers (CPTs) and geophysics to supplement borings, where appropriate.

In addition, where available, the as-built plans, conformance laboratory tests, and in-place compaction tests for the construction and improvements of each levee were retained as part of the ULDC (DWR, 2012) evaluation. This information was used to evaluate the levee geometry and material properties within the newly constructed and improved levee sections.

Sources of information for AECOM’s review include the following:
 The GDR, PIR, and GERPD for information on surficial geologic mapping and geomorphic assessments from various consultant reports, including URS - AMEC Geomatrix (2009, 2011), Fugro William Lettis and Associates (2008, 2011), and Kleinfelder (2013b)
ULDC Geotechnical Findings NEMDC Arcade South 2-5 July 22, 2024  The GDR for information on electric resistivity imaging surveys along the waterside toe of the Arcade Creek levees and along the crown and toe of the NEMDC east levee (about 10,700 feet in total)
 GDR, PIR and GERPD for boring logs to develop subsurface profiles and laboratory testing on borehole samples used to characterize soil layers for analysis. Borings, sampling, and testing are covered by reports prepared by USACE (1954), Caltrans (1967), Wahler Associates (1987), Kleinfelder (1994a 1994b, 1995, 2002, 2013a, 2013b), Parikh (2006), URS/AMEC Geomatrix (2009, 2011, URS and AECOM covered in GDR and GERPD reports
 GDR for groundwater information developed from piezometers installed in separate boreholes adjacent to investigation boreholes. Depths ranged to 20 to 66 feet

2.2.1 Subsurface investigations
Table 2-3 and Table 2-4 summarize bore hole drilling statistics for NEMDC and ACSL.

Boring logs and location maps are included in the GERPD and GDR documents. Logs and subsurface profiles are also included in the record drawings (AECOM, 2020).

Table 2-3 Subsurface Explorations – NEMDC
Exploration
Location
Number of
Explorations
Average Spacing
(feet)
Waterside 2
Levee Crown 9 323
Landside Toe 6 329
Landside Field
Total 17
Table 2-4 Subsurface Explorations – ACSL
Exploration
Location
Number of
Explorations
Average Spacing
(feet)
Levee Crown 27 357
Landside Toe 4 2,000
Total 31
The boring count only includes deeper borings ranging from 35 to 80 feet below grade.

Shallower borings used to investigate levee slopes and waterside near surface conditions are not included, but still provide useful data on levee soil composition and blanket conditions. It should be noted that locating and drilling bore holes away from the levee crown along both NEMDC and ACSL was inhibited by factors, including lack of access to landside toe areas due to property lines being located near the levee toe, ponding conditions that limited access on the waterside in some locations, and environmental restrictions preventing access on the waterside due to the presence of delineated wetlands.

ULDC Geotechnical Findings NEMDC Arcade South 2-6 July 22, 2024 Deep centerline and toe slurry cutoff walls were installed along NEMDC and significant portions of ACSL as part of the most recent remediation work completed by AECOM for SAFCA (reference record drawings [AECOM, 2020]). During cutoff wall installation, excavations were monitored, and trench logs were prepared by AECOM every ten feet on average. Logging was used to verify actual conditions against soil profiling used for design on a real time basis. Where variations were noted, conditions were evaluated by the AECOM design staff and the slurry wall depth was varied up or down as needed to ensure penetration into suitably dense, low permeability materials.

In areas along ACSL without a slurry cutoff wall, the channel is incised relative to the landside toe and hydraulic head above the landside toe is low. This is particularly true for the upper end of ACSL where the hydraulic head on the levee for the DWSE at critical analytic sections is 4.5 feet or less. Historic performance shows no landside seepage issues.

An independent consulting board for SAFCA reviewed and approved the scope of field exploration and designs, and periodically reviewed construction progress for the most recent remediation work completed. Their work included reviewing the historic background geotechnical data as part of their review of planned explorations for the most recent improvements to identify and close any potential gaps.

2.2.1.1 Conclusion
Geotechnical data supporting levee analyses includes levee and foundation drilling, surficial geologic mapping and geomorphic assessments, resistivity surveys, construction observations during recent deep slurry cutoff wall and slope reconstruction work, other historic construction records, and past performance evaluations. While the extent of drilling may not meet SPK SOP (USACE, 2022) guidelines, AECOM believes site characterization documentation based on all the data available from the different investigations and observations methods described above is adequate to support geotechnical analyses and to verify compliance with the ULDC requirements through exception.

2.2.2 Sampling and Testing
Borings were sampled and logged in accordance with ASTM D1586. Soils were classified in accordance with ASTM specification D2488 and the Unified Soil Classification System (ASTM D2487). Undisturbed samples were also obtained at selected locations in borings based on the boring logs to obtain representative samples for laboratory testing to support seepage and stability analyses and settlement evaluations.

The GDR documents describe sampling and testing programs and the use of the results to assist in defining soil layering and soil characteristics for the critical sections used in design analyses. Results are summarized in tables in the GDR and GERPD.

2.2.2.1 Conclusion
Based on AECOM’s review of the sampling and testing program, including reviews by SAFCA’s independent consulting board, AECOM believes the program is adequate to define soil layering and soil characterizations used in levee design analyses.

ULDC Geotechnical Findings NEMDC Arcade South 2-7 July 22, 2024

2.3 ULDC SECTION 7.4 SLOPE STABILITY FOR INTERMITTENTLY LOADED LEVEES
This section provides a summary of AECOM’s review of existing geotechnical stability analyses for NEMDC and ACSL and our conclusions regarding compliance with ULDC Section 7.4, Slope Stability.

The ULDC provides the following definition for intermittently loaded levees:
“Intermittently loaded levee means a levee that does not experience a water surface elevation of one foot or higher above the elevation of the levee toe at least once a day for more than 36 days per year on average.”
The NEMDC east and Arcade Creek south levees are considered intermittently loaded because historical flood hydrographs confirm short-term peak flood flow events. ULDC requirements and criteria for intermittently loaded levees as reproduced below apply.

ULDC Section 7.4, Slope Stability for Intermittently Loaded Levees: Requires slope stability analysis for the design water surface elevation (DWSE) and at the Hydraulic Top of Levee (HTOL) WSE. “Engineers should use sound engineering judgment and guidance from EM 1110-2-1902 to decide what constitutes a minor, insignificant slip surface versus a sliding surface that threatens the integrity of the levee. These determinations should be based on performance history, levee geometry, type of levee fill material, stratigraphy of the levee embankment and foundation soils, seepage conditions (including pore water pressures calculated for the seepage analysis), soil strength characteristics, and potential for erosion. Those surfaces which significantly threaten the integrity of the levee must meet minimum slope stability criteria.” Steady-state landside stability and rapid drawdown waterside stability should be evaluated using the minimum factors of safety summarized in Table 2-5.

Table 2-5 Minimum ULDC Safety Factors for Slope Stability Stability Analysis ULDC Minimum Factor of Safety1
Steady-State DWSE, Landside Slope 1.4
Steady-State HTOL WSE, Landside Slope 1.2
Rapid Drawdown DWSE, Waterside Slope 1.0-1.2
End of Construction2 1.3

1. Critical failure surface should intersect the levee crown and exceed a minimum of 3-foot depth into the level slope.

2. End of construction case does not apply due to the age of the levees, including the most recent repairs in 2018.

AECOM reviewed the slope stability evaluations for the critical sections listed in Table 2-2 to verify compliance with the ULDC safety factors given in Table 2-5. The evaluations included applicable underseepage and through seepage pressure gradients from seepage analyses discussed in Section 2.4. Analysis results are summarized in tables in Appendix B. Required safety factors equal or exceed what is required for each design case listed in Table 2-5. As discussed previously in Section 2.1.7, the updated ULDC Geotechnical Findings NEMDC Arcade South 2-8 July 22, 2024 MBK 2024 water levels confirm the stability analyses using the MBK 2014 DWSEs and HTOLs are still applicable.

2.3.1 Conclusion
NEMDC and ACSL have been evaluated and found to meet slope stability criteria using the 200-year DWSE and HTOL water levels. Underseepage and through seepage evaluations for the DWSE condition are reflected in the analyses. Levee crest profiles and levee cross sections used previously for slope stability analyses are consistent with recent surveys (Psomas, 2023) and reevaluations at critical sections is not necessary.

Based on a review of available construction records, geotechnical data, construction materials, construction quality control and quality assurance testing, historic performance, and the slope stability analysis referenced in this report, AECOM believes that NEMDC and ACSL meet the ULDC requirements for 7.4, Slope Stability, for intermittently loaded levees.

2.4 ULDC SECTION 7.5 UNDERSEEPAGE
This section provides a summary of AECOM’s review of existing geotechnical seepage analyses for NEMDC and ACSL and conclusions regarding compliance with ULDC Section 7.5, Underseepage. The general requirements of this ULDC section for intermittently loaded levees are reproduced below.

ULDC Section 7.5, Underseepage: Requires seepage analysis performed for the design water surface elevation (DWSE) and the hydraulic top of levee (HTOL) WSE. Exit gradients measured at the landside levee toe, seepage berm toe, ditches, canals, depressions, or areas of thin blanket. The allowable maximum exit gradients are summarized in Table 2-6.

Table 2-6 Allowable Exit Gradients
Seepage Analysis Location Allowable Maximum Exit Gradient Steady-State DWSE
Landside Levee Toe 0.52,3
Ditches, canals,
depressions, berms 0.5-0.81,2,3
Steady-State HTOL WSE
Landside Levee Toe 0.62,3
Ditches, canals,
depressions, berms 0.6-0.92,3

1. The allowable underseepage exit gradient through the combined seepage berm/blanket layer between the levee toe and the seepage berm toe for a water surface set at the DWSE is determined by interpolation, using 0.5 at the levee toe and

0.8 at the seepage berm toe.

2. Maximum allowable exit gradient at the landside levee toe is 0.5 and up to 0.8 at 150 feet from the levee toe, using linear interpolation for distances in between. ULDC (DWR, 2012) does allow for higher exit gradients at the seepage berm toe provided sound engineer judgement, and additional analysis. For the HTOL, “In general if the berm is less than 100-ft wide, the maximum exit gradient may increase by up to 20 percent of the DWSE maximum exit gradient. “

3. ULDC (DWR, 2012) 7.5 provides criteria for blanket layer soils with saturated unit weights of 112 pcf or less.

As discussed previously in Section 2.1.7, the updated MBK 2024 water levels confirm the seepage analyses using the MBK 2014 DWSEs and HTOLs are still applicable.

AECOM reviewed the seepage evaluations for the critical sections shown in Table 2-2 to verify compliance with the ULDC allowable exit gradients given in Table 2-6. Analysis results are summarized in tables in Appendix B. AECOM reviewed completed remediation construction records where available. AECOM also evaluated the only inground pool located along ACSL at Station 4060+00. The seepage analysis results for ULDC Geotechnical Findings NEMDC Arcade South 2-9 July 22, 2024 the pool area are discussed in Section 2.4.1 below and seepage analysis exit gradients for pools meet criteria summarized in Table 2-6.

2.4.1 In-ground Pool Evaluation, Station ACSL 4060+00
AECOM completed a seepage analysis for the only existing in-ground pool located landside of ACSL at Sta 4060+00 using the 200-year DWSE (Refer to Figure 1 for approximate location). Results show an exit gradient of 0.37 which is less than the 0.5 allowable in the ULDC criteria. The analysis assumes water in the pool during the DWSE flood event. Results of the analysis are provided on figures included at the end of Appendix B.

2.4.2 Conclusion
NEMDC and ACSL have been evaluated and found to meet seepage exit gradient criteria using the 200-year DWSE and HTOL water levels. Levee crest profiles and levee cross sections used previously for seepage analyses are consistent with recent surveys (Psomas, 2023) and updates at critical sections is not necessary. AECOM evaluated seepage for the only in-ground pool located at ACSL Station 4060+00, which meets the allowable seepage gradient. Based on a review of available construction records, geotechnical data, construction materials, construction quality control and quality assurance testing, historic performance, and the post-construction seepage analysis referenced in this report, AECOM believes that the NEMDC east levee and ACSL meet the ULDC Section 7.5 requirements for underseepage for intermittently loaded levees.

2.5 ULDC SECTION 7.7 SEISMIC VULNERABILITY
A seismic vulnerability analysis was performed by Kleinfelder to evaluate liquefaction potential and pseudo static stability. This evaluation is summarized in the 2024 Kleinfelder Seismic Performance Summary Report included with Kleinfelder’s due diligence report. That report can be found in Appendix E in MBK’s Engineer’s Report.

The seismic vulnerability analysis concluded the ACSL and NEMDC levees have low seismic vulnerability based on acceptable factors of safety against liquefaction.

Therefore, a post-earthquake remediation plan required under ULDC 7.7.1 is not required.

2.6 ULDC SECTION 7.8 LEVEE GEOMETRY
ACSL and NEMDC levees are classified as minor stream levees, and the following minimum geometric requirements are provided in ULDC Section 7.8:
 2H:1V landside slope
 12-foot-wide levee crown
 3H:1V waterside slope
Psomas obtained representative levee cross sections (Psomas, 2024) to evaluate the existing geometry with the ULDC criteria. Cross sections for ACSL and NEMDC prepared by MBK are included in Appendix D. Each section shows two profiles, the required ULDC geometry and the surveyed cross section. The crest elevation for the required geometry section is the design water surface elevation plus three feet for ULDC Geotechnical Findings NEMDC Arcade South 2-10 July 22, 2024 minimum freeboard; the centerline is the historic centerline. The cross sections show the levee is typically overbuilt.

Since originally constructed, remediation projects have modified the original levees, including geometry. However, record drawing sections for past remediations as well as the recent Psomas survey data verify compliance with the ULDC geometry criteria.

2.6.1 Conclusion
Based on the record drawings and the recent Psomas cross section surveys, AECOM believes the NEMDC east levee and ACSL meet the requirements for ULDC Section

7.8, Levee Geometry.

2.7 ULDC SECTION 7.9 INTERFACES AND TRANSITIONS
This section addresses NEMDC and ACSL compliance with the requirements of ULDC Section 7.9, Interfaces and Transitions. Conclusions regarding compliance are based on AECOM’S review of existing information contained in the reports listed in Section 2.1.3.

ULDC Section 7.9 contains the following requirements:

The civil engineer must consider, evaluate, and explicitly design for interfaces and transitions between different types of levee sections and features along a levee system.

Appropriate overlaps, transitions, and connections between features must be evaluated and designed to ensure that the levee system functions holistically, such that no levee reach is more susceptible to problems than an adjacent reach due to gaps in features, loading/demand concentrations, or other three-dimensional effects. Such interfaces, transitions, and connections commonly occur at the ends of seepage berms, seepage cutoff walls, revetments, and floodwalls.

Table 2-7 lists the interfaces, transitions, and gaps present within NEMDC and ACSL that are evaluated in this section.

Table 2-7 Interfaces, Transitions, and Gaps
Condition Description Location
Interface End of Toe Slurry Cutoff Wall Station 3029+00 NEMDC Gap Gap in Slurry Cutoff Wall
Between Station 3051+00 NEMDC
and
Station 4001+85 ACSL
Interface End of Centerline Slurry Cutoff Wall Station 4013+00 ACSL Interface End of Centerline Slurry Cutoff Wall Station 4031+18 ACSL Gap Lateral Gap Between Offset Toe and
Centerline Slurry Cutoff Walls Stations 4065+20 to 4067+00 ACSL Interface End of Toe Slurry Cutoff Wall Station 4083+21 ACSL Transition End of Levee at Marysville Blvd. Station 4110+00 ACSL Transition Centerline Slurry Cutoff Walls at
Existing Road Crossings
ACSL
Station 4035+10 at Norwood Avenue
Station 4063+00 at Bike Trail Bridge
ULDC Geotechnical Findings NEMDC Arcade South 2-11 July 22, 2024

2.7.1 Toe Cutoff Wall Interface - Station 3029+00
NEMDC was originally constructed in the 1930s on the waterside of an existing Union Pacific Railroad (UPRR) embankment. Waterside levee enlargement occurred in 1995 and 1996 and consisted of 1-foot to 3-foot levee raises and widening.

The PIR (URS, 2014d) analysis for NEMDC indicates the following:
 The levee between NEMDC Stations 3029+00 and 3034+00 marginally meets ULDC criteria for underseepage for the 200-year and HTOL cases  The levee between NEMDC Stations 3034+00 and 3051+00 fails to meet ULDC criteria for underseepage because of the presence of a thin fine-grained blanket overlying an aquifer
Based on the Alternatives Analysis Report (AAR) (URS, 2014c), the preferred improvement for underseepage between NEMDC Stations 3034+00 and 3051+00 was constructing a waterside slag cement-cement-bentonite (SCCB) toe cutoff wall with select levee fill placed over the wall and tied into an existing waterside clay blanket on the levee slope.

SAFCA and the AECOM team decided to extend the toe cutoff wall downstream an additional 500 feet to NEMDC Station 3029+00 as a resilience measure. This would avoid potential future seepage remediations for this section of levee, which marginally meets ULDC criteria. Downstream from NEMDC Station 3029+00, the levee meets ULDC criteria based on evaluations by other consultants as described in their reports.

Based on GERPD and PIR documents, there is no potential for adverse NEMDC levee settlement or end around seepage upstream or downstream of the interface at NEMDC Station 3029+00.

2.7.1.1 Conclusion
The completed installation of a toe slurry cutoff wall between NEMDC Stations 3034+00 and 3051+00 has remediated underseepage for 200-year DWSE and HTOL cases.

Further, as a resiliency measure, the toe slurry cutoff wall was extended further downstream from NEMDC Station 3034+00 to NEMDC Station 3029+00 since analyses showed this levee segment only marginally met ULDC criteria. Analyses by AECOM and others confirm the levee downstream of the interface at NEMDC Station 3029+00 conforms to ULDC criteria and end around seepage and settlement is not a concern.

Based on the above information, it is AECOM’s opinion that the levee section and toe wall interface at NEMDC Station 3029+00 meets the geotechnical requirements of ULDC Section 7.9, Interfaces and Transitions.

2.7.2 Cutoff Wall Gap, NEMDC Station 3051+00 to ACSL Station 4001+85 As indicated in Figure 1, NEMDC merges with ACSL at the NEMDC/Arcade Creek confluence. As indicated in the GERPD and PIR documents, and described above, NEMDC upstream of NEMDC Station 3034+00 did not meet ULDC criteria for underseepage and a toe slurry cutoff wall was installed for remediation. Similar subsurface conditions exist under the ACSL, and a centerline slurry cutoff wall was ULDC Geotechnical Findings NEMDC Arcade South 2-12 July 22, 2024 installed beginning at ACSL Station 4001+85 for remediation of seepage and associated slope stability concerns.

It was not possible to merge the NEMDC toe wall with the ACSL centerline wall at the confluence because the UPRR would not grant a right-of-entry to their property for construction. As a result, the NEMDC toe slurry wall terminates at Station 3051+00 and the ACSL centerline slurry wall began at Station 4001+85 to avoid encroaching on UPRR property. This left a gap in protection across railroad property. This gap also includes a low clearance railroad trestle. AECOM evaluated this gap for compliance with ULDC criteria.

A two-dimensional seepage analysis was performed for the cutoff wall gap. As described in the GERPD, an analysis cross-section was developed for the shortest seepage path through the gap, which was determined to be on the Arcade Creek side of the railroad. Seepage paths are typically longer on the NEMDC side. Table 2-8 summarizes the results of the seepage analyses from the GERPD that indicate ULDC seepage criteria is met across the gap, and no special closure remediation is needed.

Table 2-8 Gap Seepage Analysis Results
Flood Level WSE
(feet,
NAVD88)
Vertical Exit Gradient
[Location, criteria]
Comments
200-year DWSE 39.0 0.44 [Toe, icriteria=0.5] Meet underseepage and through seepage criteria HTOL WSE 42.0 0.54 [Toe, icriteria=0.6] It should be noted that there is a City of Sacramento interior drainage pump station on the landside of the levees at the confluence that does not encroach into the landside toes of NEMDC or ACSL. The pump station includes an excavated, concrete-lined runoff collection basin. As part of the gap seepage evaluation, AECOM evaluated the stability of the collection basin bottom slab assuming flood conditions in the creek and a drained basin. This analysis is described in the GERPD. Results indicated the basin did not influence the levee gap seepage analysis and residual underseepage pressure at the basin was not a concern. However, as a resiliency measure, a drainage relief trench was installed in the bottom of the basin. The basin analysis and relief trench design are documented in the GERPD.

2.7.2.1 Conclusion
The gap seepage analysis shows that vertical exit gradients at the critical section for seepage conform with the applicable ULDC criteria. Analyses in the GERPD confirm that slope stability is not an issue for NEMDC, or for ACSL in the gap area following construction of the toe and centerline slurry cutoff walls. Analysis also indicates that the presence of City of Sacramento pump station sump landside of the levees does not influence results for the critical seepage section analyzed for the gap. Records reviewed show no indication of poor performance in and around the gap area. Based on GERPD and PIR documents, there is no potential for adverse levee settlement. It is AECOM’s opinions that the gap area conforms with the geotechnical requirements of ULDC ULDC Geotechnical Findings NEMDC Arcade South 2-13 July 22, 2024 Section 7.9, Interfaces and Transitions, as well as the other ULDC sections covering seepage and slope stability.

2.7.3 Slurry Cutoff Wall Interface, ACSL Station 4013+00 Originally constructed in early 1930s using waterside borrow. Levee improvements were made around 1957 by USACE by widening the existing levee toward the waterside to provide a 20-foot crown width and a 2H:1V slope.

The PIR (URS, 2014d) analysis indicates the levee between ACSL Stations 4001+85 (UPRR property line) and 4013+00 did not meet ULDC criteria for underseepage and stability. Based on the AAR (URS, 2014c), the preferred improvement for both problems was to construct a centerline soil-bentonite slurry cutoff wall between ACSL Stations 4001+85 and 4013+00. Based on a review of construction record documents, the centerline wall has been successfully installed.

The existing levee upstream from the end of the centerline slurry cutoff wall at ACSL Station 4013+00 was found to meet ULDC criteria as described in the PIR analysis (URS, 2014d). Since end around seepage analysis results at the cutoff wall interface at ACSL Station 4013+00 met criteria, further extension of the centerline slurry cutoff wall upstream beyond ACSL Station 4013+00 was not required. Analysis also indicates that the remediated levee between ACSL Stations 4001+85 and 4013+00 meets ULDC stability criteria after the centerline slurry cutoff wall was installed, and settlement is also not a concern.

2.7.3.1 Conclusion
Based on the above information, it is AECOM’s opinion that the interface at ACSL Station 4013+00 meets the geotechnical requirements of ULDC Section 7.9, Interfaces and Transitions.

2.7.4 Slurry Cutoff Wall Interface, ACSL Station 4031+18 Originally constructed in the early 1930s with waterside borrow. Levees were improved around 1957 by USACE by widening the existing levee toward the waterside to provide a 20-foot crown width and a 2H:1V slope.

AECOM’s PIR analysis (URS, 2014d) indicates ACSL between Stations 4031+18 and 4068+45 does not meet ULDC criteria for underseepage, through seepage, and stability. Based on AECOM’s AAR (URS, 2014c) for the segment, the selected improvement for underseepage, through seepage, and stability was constructing a soilbentonite slurry cutoff wall along the centerline of the levee crown between ACSL Stations 4031+18 and 4068+45. Based on a review of completed construction records, the centerline wall has been successfully installed.

At the downstream end, the centerline cutoff wall at ACSL Stations 4031+18 interfaces with existing levee determined to meet ULDC criteria for seepage, stability, and settlement as documented in the PIR (URS, 2014b). End-around seepage at the interface was not found to be an issue, and further extension of the centerline slurry cutoff wall downstream from Station 4031+18 was not required. GERPD and PIR documents also indicates that stability, settlement, and seepage are not a concern ULDC Geotechnical Findings NEMDC Arcade South 2-14 July 22, 2024 between ACSL Stations 4031+18 and 4068+45 following construction of the centerline slurry cutoff wall.

2.7.4.1 Conclusion
Based on the above information, it is AECOM’s opinion that the above-described centerline slurry cutoff wall interface at ACSL Station 4031+18 meets the geotechnical requirements of ULDC Section 7.9 for Interfaces and Transitions.

2.7.5 Slurry Cutoff Wall Gap, ACSL Stations 4065+20 to 4067+00 Aa mentioned above, ACSL at Stations 4068+45 near Rio Linda Boulevard did not meet ULDC criteria for underseepage, through seepage, and stability and a soil-bentonite slurry cutoff wall was constructed along the centerline of the levee for remediation based on recommendations in the AAR (URS, 2014c). Upstream of ACSL Station 4068+45, between Stations 4068+45 and 4083+21, AECOM’s PIR analysis (URS, 2014d) analysis showed that the levee did not meet ULDC underseepage and stability criteria, and the preferred improvement was to construct a waterside toe SCCB slurry cutoff wall combined with waterside slope reconstruction to remediate the seepage and stability issues.

It was impractical to adequately merge the centerline and toe cutoff wall remediations described above due to topographic constraints, utility interferences, the presence of the Rio Linda bridge, and existing freeboard floodwalls and curbs east of Rio Linda Boulevard. To avoid these constraints, the centerline slurry cutoff wall was terminated at ACSL Station 4067+00 just west of Rio Linda Boulevard and the toe cutoff wall was continued downstream under the Rio Linda bridge to ACSL Station 4065+20. This resulted in an offset overlap between the centerline and toe cutoff walls 180 feet long.

The offset gap as shown on the record drawings (URS, 2020) is approximately 65 feet wide. As documented in the GERPD, AECOM evaluated the offset.

To evaluate the gap between the two walls, a two-dimensional seepage analysis was performed as described in the GERPD (AECOM, 2016). Analysis cross-sections encompassing both walls were developed following the shortest seepage path through the cutoff wall gap from the waterside channel toward the landside. Analyses were performed assuming a range of cutoff wall overlap lengths to determine the minimum overlap distance needed to meet ULDC underseepage criteria. As documented in the GERPD, a minimum overlap of 110 feet was required to meet criteria for 200-year and HTOL water surface cases. The constructed overlap is longer, approximately 180 feet, based on the record drawings.

2.7.5.1 Conclusion
Based on the above information and a review of completed construction records, it is AECOM’s opinion that the centerline slurry cutoff wall overlap with the toe cutoff slurry wall at Rio Linda Boulevard between ACSL Stations 4065+20 and 4067+00 meets the geotechnical requirements of ULDC Section 7.9, Interfaces and Transitions.

2.7.6 Slurry Cutoff Wall Interface, ACSL Station 4083+21 Originally constructed in early 1930s with waterside borrow (Kleinfelder, 2013a). A 1996 levee raise increased available freeboard using reinforced concrete curb walls of ULDC Geotechnical Findings NEMDC Arcade South 2-15 July 22, 2024 varying height above the levee crown extending from Rio Linda Boulevard east to Marysville Boulevard (ACSL Stations 4068+50 to 4110+00).

The PIR (URS, 2014d) analysis indicates this segment does not meet ULDC (DWR, 2012) criteria for underseepage, through seepage, and stability. Based on AECOM’s AAR, the preferred improvement was to construct a SCCB slurry cutoff wall at the waterside toe of the levee combined with waterside slope reconstruction; each has been successfully constructed.

At ACSL Station 4083+21, the toe slurry cutoff wall and waterside slope reconstruction interfaces with existing upstream levee determined to meet all ULDC criteria as documented in the PIR analysis (URS, 2015b). Since end around seepage at ACSL Station 4083+21 was not determined to be an issue, further extension of the toe slurry cutoff wall and slope reconstruction upstream was not required. GERPD and PIR documents also indicates that stability, settlement, and seepage are not a concern between ACSL Stations 4065+20 and 4083+21 following construction of the centerline slurry cutoff wall.

2.7.6.1 Conclusion
Based on the above analysis information and a review of the completed construction record drawings, it is AECOM’s opinion that the above-described toe slurry cutoff wall interface at Station 4083+21 meets the geotechnical requirements of ULDC Section 7.9, Interfaces and Transitions.

2.7.7 ACSL End Transition at Marysville Boulevard
ACSL terminates at Marysville Boulevard at approximate ACSL Station 4110+00. At this location, the levee crown also includes a freeboard wall as mentioned previously. The levee is set back from the creek approximately 60 feet, and the flood duration is short.

As indicated in the GDR documents, the levee was investigated to develop geotechnical data needed for seepage and stability analyses. Results of the analyses showing compliance with ULDC criteria are shown in Appendix B. A review of construction documents, and historic satisfactory performance at the transition indicate the levee and associated crest wall interfaces with the road were constructed to required standards.

Analysis of subsurface data and performance also indicates settlement at the transition is not a concern.

2.7.7.1 Conclusion
Based on the above review it is AECOM’s opinion that the termination of ACSL at Marysville Boulevard meets the geotechnical requirements of ULDC Section 7.9, Interfaces and Transitions.

2.7.8 Arcade Creek South Levee Transitions at Road Crossings As shown in Figure 1, ACSL crosses the following two roads:
 Norwood Avenue, ACSL Station 4035+10
 Sacramento Northern Bile Trail, ACSL Station 4063+00
ULDC Geotechnical Findings NEMDC Arcade South 2-16 July 22, 2024 The levees at the crossings include a centerline soil-bentonite (SB) slurry cutoff wall. At each crossing, the SB wall was discontinued, and a slag cement-cement-bentonite (SCCB) wall with the same depth was constructed across the road to address seepage and minimized road closure time. The SCCB wall was constructed first, followed by construction of the SB wall on both sides with a direct contact overlap of the wall a minimum of 25 feet long. Crossing details are shown in the record drawings (AECOM, 2020).

As indicated in the GDR documents, the levees were investigated to develop geotechnical data needed for seepage and stability analyses. These investigations include a boring on the Norwood Avenue shoulder, and a cone penetrometer hole and nearby bore hole at the bike trail crossing. Results of the analyses presented in Appendix B and the GERPD show compliance with ULDC criteria after slurry cutoff wall construction. Analysis of subsurface data and performance history indicate settlement at or adjacent to road crossings are not a concern.

As discussed in Section 2.7.5, there are no slurry wall crossings of Rio Linda Boulevard.

In addition, there are no interfaces of levees or levee improvements with existing flood walls constructed on the levee crown extending from Rio Linda Boulevard east to Marysville Boulevard (ACSL Stations 4068+50 to 4110+00) that require evaluation.

2.7.8.1 Conclusion
Based on the above review it is AECOM’s opinion that the transitions at road crossings described in this section meet the geotechnical requirements of ULDC Section 7.9, Interfaces and Transitions.

2.8 ULDC SECTION 7.10 EROSION
This section addresses the potential for surface or internal erosion developing where seepage analyses indicate through seepage could exit the landside slope at or above the levee toe. Erosion evaluation for the waterside levee slope for ULDC compliance is addressed in reports prepared by other consultants.

2.8.1 NEMDC East Levee
Based on seepage evaluation results included in Appendix B, the NEMDC East Levee between Stations 3029+00 and 3034+00 (Reach NE-1) meets ULDC seepage criteria but could have phreatic surface breakout above the landside toe in soils classified as clay (CL). Between stations 3034+00 and 3051+00 (Reach NE-2) there is no breakout above the landside toe for the section evaluated Since soils are consistent in the levee, the section evaluated is considered representative of the reach. Based on these findings, landside toe erosion due to seepage is not considered a risk.

2.8.2 Arcade Creek South Levee
Based on seepage evaluation results included in Appendix B, ACSL between Stations 4000+00 and 4013+00 (Reach ARS-1) meets ULDC seepage criteria after centerline slurry cutoff wall remediation. However, one section evaluated showed minor surface breakout above the toe in soils classified as clay (CL). The other showed no breakout on the slope. Because of these findings, landside toe erosion due to seepage is not considered a risk.

ULDC Geotechnical Findings NEMDC Arcade South 2-17 July 22, 2024 Based on seepage evaluation results included in Appendix B, ACSL between 4013+00 and 4031+18 (Reach ARS-2) meets ULDC seepage criteria. However, the section evaluated for seepage showed surface breakout in soils classified as clayey sands (SC). There is no record of poor performance in this reach due to seepage erosion at the toe. Because of these findings, landside toe erosion due to seepage is not considered a risk for the levee.

Based on seepage evaluation results included in Appendix B, ACSL between Stations 4031+18 and 4068+45 (Reach ARS-3) meets ULDC seepage criteria after installation of a centerline slurry cutoff wall. However, the two sections evaluated show minimal breakout of seepage (0.8 to 1.5 feet) in soils classifies as clayey sand (SC) or silty sand (SM). There is no record of poor performance in this reach due to seepage erosion at the toe and flooding is intermittent. Because of these findings, landside toe erosion due to seepage is not considered a risk for the levee.

Based on seepage evaluation results included in Appendix B, ACSL between Stations 4068+45 and 4083+21 (Reach ARS-4) meets ULDC seepage criteria after toe cutoff wall construction and waterside slope reconstruction. The section evaluated shows no seepage breakout on the landside slope. In addition, the hydraulic head is low in this reach (six feet or less) for the DWSE and there are no records of poor performance.

Based on these findings, landside toe erosion due to seepage is not considered a risk for the levee.

Based on seepage evaluation results included in Appendix B, ACSL between Stations 4083+21 and 4110+00 (Reach ARS-5) meets ULDC seepage criteria with no remediation required. The three sections evaluated showed no seepage breakout, or minimal breakout (0.3 to 2.5 feet) in clayey sand (SC) soils. The hydraulic head is minimal (1.1 to 3.7 feet) for the DWSE and there are no records of poor performance.

Because of these findings, toe erosion due to seepage is not considered a risk for the levee.

2.9 ULDC SECTION 7.13 PENETRATIONS
Compliance with ULDC criteria for penetrations in the levees is addressed in reports prepared by other consultants. This section provides supplemental geotechnical-related information related to penetrations.

2.9.1 Review of Penetration Data
As part of AECOM’s evaluation of NEMDC and ACSL, the tabulation of known penetrations in the penetration report prepared by Mead & Hunt was compared with penetrations shown on the record drawings. Any inconsistencies were noted and resolved. Also, wherever possible, AECOM confirmed suitable abandonment of culverts and other utilities as part of its inspections performed during the most recent levee remediation work.

There are small diameter active gas and electric penetrations remaining in the levees.

These were reviewed by AECOM on a case-by-case basis and AECOM verified that the penetrations do not present a hazard to the levee from the geotechnical perspective.

ULDC Geotechnical Findings NEMDC Arcade South 2-18 July 22, 2024

2.9.2 Drainage Pipe Reconstruction, Station 4076+60
A previously unidentified 18-inch-diameter drainage pipe was encountered in slope reconstruction excavations at ACSL Station 4076+60 (refer to Figure 1 for approximate location). To avoid construction delays to replace the culvert, the toe slurry cutoff wall installation and waterside slope reconstruction work was completed. A design was subsequently prepared by Peterson Brustad, Inc. (PBI) to replace the pipe.

Replacement included a new pipe, a slide gate vault at the waterside edge of levee crow, and flap gate outlet. Replacement included removing and replacing levee fill on the slope and installing the pipe through the completed slurry wall.

AECOM provided PBI criteria for removing and replacing levee fill and repairing the toe slurry cutoff wall after pipe installation. AECOM also provided field observation of the earthwork and wall repair during construction to confirm compliance with the geotechnical requirements. Observation of the existing SCCB slurry wall exposed in the excavation showed it to be well constructed. AECOM believes the drainage pipe installation and slurry wall repair meets geotechnical criteria and poses no seepage or stability threat to the levee.

PBI provided a set of post-construction record design drawings for the drainage pipe replacement work and other minor improvements showing design details (PBI, 2019).

2.9.3 AT&T Duct Bank, Station 4067+60
AT&T did not raise an existing concrete encased duct bank at approximate ACSL Station 4067+60 (refer to Figure 1 for location) above the DWSE as required prior to the start of levee remediation work required in the area. To avoid construction delays, the contractor avoided excavating the upper slope over the duct bank to construct a toe slurry cutoff wall. Subsequently, AECOM evaluated the geotechnical characteristics of the existing slope over the duct bank and determined that raising the duct bank would not be needed if the slope was excavated to a depth of 3 feet and replaced with compacted select levee material to provide a low permeability blanket extending a specified distance upstream and downstream of the duct bank.

AECOM prepared a design for the blanket excavation and backfill work. AECOM also evaluated the proposed borrow area to confirm material suitability and provided site observations of the construction for SAFCA. A memorandum in Appendix E includes plans documenting the slope blanket design and a record of construction observations and findings.

AECOM believes the blanket construction over the concrete encased duct bank satisfactorily addresses concern for seepage along the exterior of the duct bank for the DWSE condition. Also, the concrete encasement is continuous across Arcade Creek and up both waterside slopes preventing entry of water into the conduits.

2.10 ULDC SECTION 7.14 FLOODWALLS, RETAINING WALLS, AND CLOSURE

STRUCTURES
This section covers geotechnical aspects of the stoplog closure structure located on the UPRR railroad on the south bank of Arcade Creek at approximate ACSL Station 4001+00 at the confluence with NEMDC. Typical details of the structure are shown on a ULDC Geotechnical Findings NEMDC Arcade South 2-19 July 22, 2024 copy of the design sheets provided in Appendix C. Reinforced concrete seepage cutoff walls cast integral with the structure are provided on the back sides of the retaining walls and under the stoplog support beam. Field inspection by AECOM indicates the structure was built according to the plans. The stoplogs used are aluminum.

Documentation includes reports of periodic test installations of the stoplogs by the City of Sacramento staff and USACE, including time to install.

AECOM understands that compacted levee backfill was placed against the sides of the structure for tie in of the NEMDC and Arcade Creek levees. During the 200-year flood event, three to four feet of water would be retained against the stoplogs. Minor, controllable seepage may occur under the stoplogs that AECOM believes would not present a threat to the levee or the protected areas on the landside. Seepage and stability analyses for NEMDC and Arcade Creek levees that abut the closure structure meet ULDC requirements as described in other sections of this report.

2.10.1 Existing Flood Walls and Curbs
It is noted that there are existing reinforced concrete freeboard curbs and low flood walls along the waterside crown of ACSL between Rio Linda Boulevard and Marysville Boulevard (ACSL Stations 4068+50 and 4110+00). These features were not disturbed or modified by any subsequent waterside remediations that flattened slopes, or by toe cutoff wall construction work. Structural evaluation of the walls is included in reports prepared by other consultants. There are no reports of poor performance of the wall during high water events. Geotechnical evaluation of Interfaces is not considered necessary.

2.10.2 Conclusion
Based on the above information, AECOM believes the closure structure meets the geotechnical requirements of ULDC Section 7.14, Floodwalls, Retaining Walls, and Closure Structures. Structural analysis of the closure structure and flood walls is the responsibility of other SAFCA consultants, and the results of those analyses are provided in their reports.

ULDC Geotechnical Findings NEMDC Arcade South 2-20 July 22, 2024 Intentional Blank
ULDC Geotechnical Findings NEMDC Arcade South 3-1 July 22, 2024

3.0 ARCADE CREEK SOUTH LEVEE AND NEMDC EAST LEVEE

STUDY AREA SUMMARY OF RESULTS
Based on the evaluations described in Section 2.0 above, Table 3-1 summarizes AECOM’s conclusions regarding levee compliance with the criteria contained in the ULDC (DWR, 2012):

Table 3-1 Summary of Results
Project Levee Stationing Meets All
Criteria
Does Not
Meet All
Criteria
ULDC Criteria Selection
NEMDC East
Levee
Stations 3029+00 to
3051+00
X
By
Exception

7.3 Soil Sampling, Testing, and
Logging. Refer to Section 2.2.1 for
discussion of bore hole data.

X 7.4 Slope Stability
X 7.5 Underseepage,
X 7.7 Seismic Vulnerability
X 7.8 Levee Geometry
X 7.9 Interfaces and Transitions
X 7.10 Erosion
X 7.13 Penetrations
X

7.14 Floodwalls, Retaining Walls, and
Closure Structures
Arcade Creek
South Levee
Stations 4000+00 to
4110+00
X
By
Exception

7.3 Soil Sampling, Testing, and
Logging. Refer to Section 2.2.1 for
discussion of bore hole data.

X 7.4 Slope Stability
X 7.5 Underseepage,
X 7.7 Seismic Vulnerability
X 7.8 Levee Geometry
X 7.9 Interfaces and Transitions
X 7.10 Erosion
X 7.13 Penetrations
X

7.14 Floodwalls, Retaining Walls, and
Closure Structures
It is AECOM’s opinion as outlined above in Table 3-1, that the NEMDC east and Arcade Creek south levees meet the geotechnical-related requirements of the ULDC.

ULDC Geotechnical Findings NEMDC Arcade South 3-2 July 22, 2024 Intentional Blank
ULDC Geotechnical Findings NEMDC Arcade South 4-1 July 22, 2024

4.0 LIMITATIONS
This Report, along with the associated data collection and preparation, has been conducted in adherence to the standard of care commonly practiced in the due diligence profession. The standard of care is defined as the ordinary diligence exercised by professionals in this field performing similar services under comparable circumstances during the same period.

Summaries of pertinent information referenced and provided in this report are based on due diligence review of available information.

No warranty, whether express or implied, is made in the provision of this report, which is the outcome of due diligence evaluation services. There is no guarantee, whether express or implied, that actual conditions on-site will precisely match the conditions described herein.

The accuracy, completeness, or reliability of data collected by third parties and referenced in this report, including, but not limited to, geotechnical borings and subsurface data, is not attested by AECOM. In the creation of this report, reliance is placed on data and information provided by external sources, without the ability for independent validation or verification.

Data presented in this report are time-sensitive and are applicable only to the locations and conditions that existed at the time of data collection. Such data should not be extrapolated to other projects in the vicinity or applied at a future date without appropriate verification.

This Geotechnical Findings Report is intended for the use and benefit of SAFCA or its designated representatives only. Any use by other parties is at their own discretion and risk.

ULDC Geotechnical Findings NEMDC Arcade South 4-2 July 22, 2024 Intentional Blank
ULDC Geotechnical Findings NEMDC Arcade South 5-1 July 22, 2024

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Fugro, William Lettis & Associates, Inc. 2008. Summary of Surficial Geologic Mapping, Natomas Basin, California Department of Water Resources Urban Levee Program, Sacramento County, California. April.

Kleinfelder, 2013a. Geotechnical Data Report, North Area Streams, SAFCA FEMA Accreditation, American River, Sacramento River downstream of American River, and Beach Lake Levee, Sacramento County, California. May.

Kleinfelder, 2013b. Problem Identification Report, North Area Streams, SAFCA FEMA Accreditation, American River, Sacramento River downstream of American River, and Beach Lake Levee, Sacramento County, California. September.

Kleinfelder, 1994a and 1994b. Geotechnical Evaluations of North and South Banks of Arcade Creek and Dry Creek.

Kleinfelder, 1995. Geotechnical Investigation Along the East Bank of NEMDC.

Kleinfelder, 2024. Seismic Performance Summary Report, North Area Streams Levee Areas, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento County, California. February 12, 2024.

MBK Engineers, 2014. Technical Memorandum, 1/10, 1/200, 1/500 AEP Water Surface Elevations for SAFCA Levee Certification Reaches. April.

MBK Engineers, 2024. Updated ULDC Water Surface Elevations, Arcade Creek South Levee and NEMDC East Levee. February 9, 2024.

Parikh. 2008. Geotechnical Investigations for Bridge Design, NEMDC East and West Banks.

PBI. 2019. Record Drawings, SAFCA NAS, Miscellaneous Improvements 2019.

Psomas, 2023. Updated levee crown and Cross Section Surveys for FEMA and ULDC compliance Reviews. December.

State of California Department of Water Resources. 2012. Urban Levee Design Criteria.

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United States Army Corps of Engineers. 1954. Sacramento River, California, Flood Control Project, American River, Natomas Canal, Arcade Creek, and Linda Creek, Levee Construction (including field boring logs.

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Technical Procedures Document. Prepared for DWR. April.

United States Army Corps of Engineers. 2005. Engineer Technical Letter 1110-2-569, Engineering and Design: Design Guidance for Levee Underseepage. May.

United States Army Corps of Engineers. 2003. Engineer Manual 1110-2-1902, Engineering and Design: Slope Stability. October.
2023.

ULDC Geotechnical Findings NEMDC Arcade South 5-2 July 22, 2024 United States Army Corps of Engineers. 2000. Engineer Manual 1110-2-1913, Engineering and Design: Design and Construction of Levees. April.

United States Army Corps of Engineers. 1993. Engineer Manual 1110-2-1901, Engineering and Design: Seepage Analysis and Control for Dams. April.

United States Army Corps of Engineers. 2023 Supplement to the Standard Operations and Maintenance Manual, Sacramento River Flood Control Project, Unit No. 118- Part No. 2, North Levee of American River, East Levee of Natomas Canal, Both Levees of Arcade Creek, South Levee of Linda Creek, and Magpie Creek Diversion Channel. October.

URS Corporation. 2014b. Geotechnical Data Report, Sacramento Flood Control Agency, North Area Streams Improvement Project. May.

URS Corporation. 2014c. Alternatives Analysis Report, Sacramento Area Flood Control Agency, North Area Streams Levee Improvement Project. August.

URS Corporation. 2014d. Problem Identification Report, Sacramento Flood Control Agency, North Area Streams Improvement Project. August.

URS Corporation. 2014e. Drain Trench System Design along Reach NAS-NE-3 (City of Sacramento Sump No. 157 at Magpie Creek).

URS Corporation. 2015a. Geotechnical Data Report, Addendum 1, Sacramento Area Flood Control Agency, North Area Streams Levee Improvement Project. February.

URS Corporation. 2015b. Problem Identification Report, Addendum 1, Sacramento Area Flood Control Agency, North Area Streams Levee Improvement Project. February.

URS Corporation. 2015c. Guidance Document for Geotechnical Analyses. Prepared for Department of Water Resources, April.

URS Corporation. 2015d. North Area Streams (NAS) Levee Improvement Project Geotechnical Data Report for Borrow Site 2K. October.

URS Corporation. 2015e. Geotechnical Data Report, Addendum 2, Sacramento Area Flood Control Agency, North Area Streams Levee Improvement Project. June.

URS Corporation. 2015f. North Area Streams (NAS) Levee Improvement Project, Geotechnical Data Report for Borrow Site 2K. October.

URS Corporation. 2016a. 100% PS&E Engineering Report, Sacramento Area Flood Control Agency North Area Streams Levee Improvement Project. August.

URS Corporation. 2016b. Addendum No. 3 to Geotechnical Data Report, North Area Streams Levee Improvement Project. August.

URS Corporation/AMEC Geomatrix. 2015b. Geotechnical Evaluation Report, Volume 2, Remedial Alternatives, NEMDC East Study Area. Prepared for Department of Water Resources. April.

URS Corporation/AMEC Geomatrix. 2011. Supplemental Geotechnical Data Report (SGDR), Natomas East Main Drainage Canal (NEMDC) East Study Area, Urban Levee Evaluations Project. November.

URS Corporation/AMEC Geomatrix. 2009. Phase 1 Geotechnical Data Report for Natomas East Main Drainage Canal (NEMDC) East Study Area, Urban Levee Evaluations Project. March.

Wahler Associates. 1987. Levee Investigation: American River Flood Control District and Maintenance Areas 10 and 11, Dry Creek, Arcade Creek, Natomas East Main ULDC Geotechnical Findings NEMDC Arcade South 5-3 July 22, 2024 Drainage Canal, American River, and Sacramento River, Sacramento County, California.

ULDC Geotechnical Findings NEMDC Arcade South 5-4 July 22, 2024 Intentional Blank

FIGURES
Figure 1 AECOM Levees Evaluated
5038+00
4060+00 In-ground Pool
AT&T Duct Bank
4076+60
Unidentified Culvert
Appendix A
ULDC 200-Year Design Water Surface Elevations
Updated ULDC Water Surface Elevations
Arcade Creek South Levee
MBK Engineers 11/14/23
Arcade Creek
South Levee
Station (ft)
DWSE
(ft, NAVD88)
HTOL
(ft, NAVD88)
Arcade Creek
South Levee
Station (ft)
DWSE
(ft, NAVD88)
HTOL
(ft, NAVD88)
4000+00 37.10 40.10 4056+00 37.88 40.88
4001+00 37.44 40.44 4057+00 37.89 40.89
4002+00 37.53 40.53 4058+00 37.90 40.90
4003+00 37.63 40.63 4059+00 37.91 40.91
4004+00 37.64 40.64 4060+00 37.92 40.92
4005+00 37.64 40.64 4061+00 37.92 40.92
4006+00 37.65 40.65 4062+00 37.93 40.93
4007+00 37.65 40.65 4063+00 37.93 40.93
4008+00 37.66 40.66 4064+00 37.92 40.92
4009+00 37.66 40.66 4065+00 38.07 41.07
4010+00 37.66 40.66 4066+00 38.12 41.12
4011+00 37.67 40.67 4067+00 38.13 41.13
4012+00 37.67 40.67 4068+00 38.14 41.14
4013+00 37.67 40.67 4069+00 38.34 41.34
4014+00 37.67 40.67 4070+00 38.37 41.37
4015+00 37.67 40.67 4071+00 38.39 41.39
4016+00 37.68 40.68 4072+00 38.42 41.42
4017+00 37.68 40.68 4073+00 38.45 41.45
4018+00 37.68 40.68 4074+00 38.48 41.48
4019+00 37.68 40.68 4075+00 38.50 41.50
4020+00 37.68 40.68 4076+00 38.52 41.52
4021+00 37.69 40.69 4077+00 38.54 41.54
4022+00 37.69 40.69 4078+00 38.56 41.56
4023+00 37.69 40.69 4079+00 38.58 41.58
4024+00 37.69 40.69 4080+00 38.60 41.60
4025+00 37.70 40.70 4081+00 38.64 41.64
4026+00 37.70 40.70 4082+00 38.67 41.67
4027+00 37.71 40.71 4083+00 38.70 41.70
4028+00 37.71 40.71 4084+00 38.74 41.74
4029+00 37.71 40.71 4085+00 38.80 41.80
4030+00 37.72 40.72 4086+00 38.87 41.87
4031+00 37.74 40.74 4087+00 38.95 41.95
4032+00 37.74 40.74 4088+00 39.02 42.02
4033+00 37.74 40.74 4089+00 39.10 42.10
4034+00 37.74 40.74 4090+00 39.16 42.16
4035+00 37.74 40.74 4091+00 39.22 42.22
4036+00 37.73 40.73 4092+00 39.28 42.28
4037+00 37.77 40.77 4093+00 39.33 42.33
4038+00 37.78 40.78 4094+00 39.39 42.38
4039+00 37.78 40.78 4095+00 39.43 42.38
4040+00 37.78 40.78 4096+00 39.46 42.38
4041+00 37.78 40.78 4097+00 39.48 42.38
4042+00 37.78 40.78 4098+00 39.51 42.38
4043+00 37.79 40.79 4099+00 39.54 42.39
4044+00 37.79 40.79 4100+00 39.70 42.41
4045+00 37.79 40.79 4101+00 39.96 42.44
4046+00 37.79 40.79 4102+00 40.21 42.47
4047+00 37.80 40.80 4103+00 40.47 42.50
4048+00 37.80 40.80 4104+00 40.73 42.54
4049+00 37.81 40.81 4105+00 40.95 42.57
4050+00 37.81 40.81 4106+00 41.12 42.60
4051+00 37.82 40.82 4107+00 41.30 42.63
4052+00 37.82 40.82 4108+00 41.47 42.66
4053+00 37.83 40.83 4109+00 41.65 42.69
4054+00 37.85 40.85 4110+00 41.82 42.73
4055+00 37.86 40.86
A-1
2023
Updated ULDC Water Surface Elevations
NEMDC East Levee
MBK Engineers 11/14/23
NEMDC
East Levee
Station (ft)
DWSE
(ft, NAVD88)
HTOL
(ft, NAVD88)
NEMDC
East Levee
Station (ft)
DWSE
(ft, NAVD88)
HTOL
(ft, NAVD88)
2986+49 35.64 38.64 3021+00 36.32 39.32
2987+00 35.65 38.65 3022+00 36.39 39.39
2988+00 35.69 38.69 3023+00 36.44 39.44
2989+00 35.72 38.72 3024+00 36.46 39.46
2990+00 35.73 38.73 3025+00 36.49 39.49
2991+00 35.74 38.74 3026+00 36.52 39.52
2992+00 35.76 38.76 3027+00 36.55 39.55
2993+00 35.77 38.77 3028+00 36.57 39.57
2994+00 35.78 38.78 3029+00 36.60 39.60
2995+00 35.80 38.80 3030+00 36.63 39.63
2996+00 35.81 38.81 3031+00 36.65 39.65
2997+00 35.82 38.82 3032+00 36.67 39.67
2998+00 35.84 38.84 3033+00 36.70 39.70
2999+00 35.85 38.85 3034+00 36.72 39.72
3000+00 35.86 38.86 3035+00 36.74 39.74
3001+00 35.92 38.92 3036+00 36.77 39.77
3002+00 35.93 38.93 3037+00 36.79 39.79
3003+00 35.94 38.94 3038+00 36.82 39.82
3004+00 35.95 38.95 3039+00 36.85 39.85
3005+00 35.96 38.96 3040+00 36.87 39.87
3006+00 35.96 38.96 3041+00 36.90 39.90
3007+00 35.97 38.97 3042+00 36.93 39.93
3008+00 35.99 38.99 3043+00 36.95 39.95
3009+00 36.02 39.02 3044+00 36.98 39.98
3010+00 36.05 39.05 3045+00 36.99 39.99
3011+00 36.08 39.08 3046+00 37.01 40.01
3012+00 36.11 39.11 3047+00 37.03 40.03
3013+00 36.14 39.14 3048+00 37.05 40.05
3014+00 36.17 39.17 3049+00 37.06 40.06
3015+00 36.20 39.20 3050+00 37.08 40.08
3016+00 36.22 39.22 3051+00 37.10 40.10
3017+00 36.24 39.24 3051+61 37.10 40.10
3018+00 36.26 39.26
3019+00 36.28 39.28
3020+00 36.29 39.29
A-2
2023
Appendix B
Geotechnical Evaluation Results Summary
SECTION 8.0 GEOTECHNICAL EVALUATION RESULTS SUMMARY
SAFCA_GERPD-Final.docx 8-2 Issue Date: 08-2016
Table 8-1. Seepage and Stability Analysis Results.

Reach and
Station for
Analysis
Section
Top of Levee
Elevation
(NAVD88,
approx.
feet)
Landside
Toe
Elevation
(NAVD88,
approx.
feet)
Levee or
Floodwall
Height
(feet)
Hydraulic
Head
(feet)
Flood
Level
Analyzed
Water
Surface
Elevation
(NAVD88,
feet)
Steady State Seepage Analysis Results Landside Slope Stability Analysis Results
Waterside Rapid Drawdown
Slope Stability Analysis
Results
Average Vertical
Exit Gradient, i [Location, Blanket
Thickness]
Breakout
Above
Landside
Toe (feet)
Comments Minimum
Factor
of Safety
Comments Minimum
Factor
of Safety
Comments
Reach NAS-NE-1 (Station 3030+00 to 3034+00, 400 feet)
Station 3032+00
Waterside SCCB
Cutoff Wall

43.2 22.0 21.1 17.4 200-year
DWSE

39.4 0.27 [Toe, blanket = 24.7 feet]

0.58 [48 feet from toe, blanket = 18.3 feet]

4.8 (CL) Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

1.74 Meets criteria for the 200-
year DWSE and HTOL
WSE
NA

20.4 HTOL
WSE

42.4 0.32 [Toe, blanket = 24.7 feet]

0.63 [48 feet from toe, blanket = 18.3 feet]

5.5 (CL) 1.60
Reach NAS-NE-2 (Station 3034+00 to 3051+00, 1,700 feet) Station 3038+00
Waterside SCCB
Cutoff Wall

43.3 19.6 23.7 19.9 200-year
DWSE

39.5 0.12* [Toe, blanket = 28.3 feet]

0.29* [29 feet from toe, blanket =

25.0 feet]

0.0 Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

2.61 Meets criteria for 200-year
DWSE and HTOL WSE

1.43 Meets criteria for
200-year DWSE with
a 13 foot drop

22.9 HTOL
WSE

42.5 0.14* [Toe, blanket = 28.3 feet]

0.34* [29 feet from toe, blanket =

25.0 feet]

0.0 2.56
Reach NAS-ARS-1 (Station 4000+00 to 4013+00, 1,300 feet) Station 4001+10
Drain Trench

44.0 24.0 20.0 14.9 200-year
DWSE

38.9 0.25* [Basin toe, blanket = 9.6 feet]

0.19* [Beneath drain trench, 13 feet from
basin toe, blanket=6.2 feet]

0.11* [15 feet from basin toe, blanket =

9.6 feet]

0.0 Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

1.55 (1.22 =
localized
stability)
Meets criteria for 200-year
DWSE and HTOL WSE
NA

17.9 HTOL
WSE

41.9 0.29* [Basin toe, blanket = 9.6 feet]

0.22* [Beneath drain trench, 13 feet from
basin toe, blanket=6.2 feet]

0.12* [15 feet from basin toe, blanket =

9.6 feet]

0.0 1.49
(1.20 =
localized
stability)
Reach NAS-ARS-1 (Station 4000+00 to 4013+00, 1,300 feet) Station 4008+00
Centerline SB
Cutoff Wall

44.5 24.1 20.4 15.9 200-year
DWSE

40.0 0.13* [Toe, blanket = 10.3 feet]

0.17* [7 feet from toe, blanket = 9.9 feet]

1.0 (CL) Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

1.48 Meets criteria for 200-year
DWSE and HTOL WSE

1.21 [Layer 3
undrained
strength
C=500 psf,
Φ=4
degrees]

1.11 [Layer 3
undrained
strength
C=125 psf,
Φ=17
degrees]
Meets criteria for
200-year DWSE with
a 12 foot drop 18.9 HTOL
WSE

43.0 0.18* [Toe, blanket = 10.3 feet]

0.22* [7 feet from toe, blanket = 9.9 feet]

1.4 (CL) 1.44
Reach NAS-ARS-3 (Station 4031+18 to 4068+45, 3,727 feet) Station 4040+00
Centerline SB
Cutoff Wall

44.1 28.6 15.5 11.5 200-year
DWSE

40.1 0.29 [Toe, blanket = 5.9 feet]

0.38 [17 feet from toe, blanket = 5.8 feet]

0.8 (SM) Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

1.73 Meets criteria for 200-year
DWSE and HTOL WSE
NA

14.5 HTOL
WSE

43.1 0.37 [Toe, blanket = 5.9 feet]

0.47 [17 feet from toe, blanket = 5.8 feet]

0.8 (SM) 1.72
Table taken from the final GERPD.

Analysis results are for remediated levees.

SECTION 8.0 GEOTECHNICAL EVALUATION RESULTS SUMMARY
SAFCA_GERPD-Final.docx 8-3 Issue Date: 08-2016
Table 8-1. Seepage and Stability Analysis Results.

Reach and
Station for
Analysis
Section
Top of Levee
Elevation
(NAVD88,
approx.
feet)
Landside
Toe
Elevation
(NAVD88,
approx.
feet)
Levee or
Floodwall
Height
(feet)
Hydraulic
Head
(feet)
Flood
Level
Analyzed
Water
Surface
Elevation
(NAVD88,
feet)
Steady State Seepage Analysis Results Landside Slope Stability Analysis Results
Waterside Rapid Drawdown
Slope Stability Analysis
Results
Average Vertical
Exit Gradient, i [Location, Blanket
Thickness]
Breakout
Above
Landside
Toe (feet)
Comments Minimum
Factor
of Safety
Comments Minimum
Factor
of Safety
Comments
Station 4063+57
Centerline
SCCB Cutoff
Wall Closure
(66-inch sewer
crossing)

45.0 34.1 10.9 6.0 200-year
DWSE

40.1 0. 29 [Toe, blanket = 14.0 feet] 1.1 (SC) Meets underseepage and through seepage criteria for 200-
year DWSE and HTOL WSE.

2.15 Meets criteria for 200-year
DWSE and HTOL WSE
NA

9.0 HTOL
WSE

43.1 0.42 [Toe, blanket = 14.0 feet] 1.5 (SC) 2.03
Reach NAS-ARS-4 (Station 4068+45 to 4083+21, 1,476 feet) Station 4079+00
Waterside SCCB
Cutoff Wall with
Waterside Slope
Replacement

43.6 (Top of
levee)

44.9 (Top of
floodwall)

34.3 9.3 (From
top of
levee)

10.6 (From
top of
floodwall)

6.2 200-year
DWSE

40.5 0.02 [Toe, blanket = 32.7 feet] Below
levee toe
Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

1.46 Meets criteria for 200-year
DWSE and HTOL WSE.

1.88 Meets criteria for
200-year DWSE with
a 12 foot drop 9.2 HTOL
WSE

43.5 0.04 [Toe, blanket = 32.7 feet] Below
levee toe

1.46 Reach NAS-ARN-3 (Station 5038+00 to 5075+00, 3,700 feet) Station 5049+00
Centerline SB
Cutoff Wall

44.5 31.9 12.4 8.2 200-year
DWSE

40.1 NA [Toe, blanket = 8.3 feet]

0.13 [17 feet from toe, blanket = 6.8 feet]

0.0 Meets underseepage and
through seepage criteria for 200-
year DWSE and HTOL WSE.

1.85 Meets criteria for 200-year
DWSE and HTOL WSE.

NA

11.2 HTOL
WSE

43.1 0.01 [Toe, blanket = 8.3 feet]

0.18 [17 feet from toe, blanket = 6.8 feet]

0.0 1.80
Station 5065+27
Centerline
SCCB Cutoff
Wall Closure
(66-inch sewer
crossing)

44.7 33.8 10.9 6.3 200-year
DWSE

40.1 0.31 [Toe, blanket = 11.1 feet] 0.0 Meets underseepage and through seepage criteria for 200-
year DWSE and HTOL WSE.

1.89 Meets criteria for 200-year
DWSE and HTOL WSE
NA

9.3 HTOL
WSE

43.1 0.45 [Toe, blanket = 11.1 feet] 0.0 1.79
Reach NAS-ARN-4 (Station 5075+00 to 5110+00, 2,500 feet) Station 5097+00
Waterside SCCB
Cutoff Wall with
Waterside Slope
Replacement

42.1 (Top of
levee)

44.0 (Top of
floodwall)

35.6 6.5 (From
top of
levee)

8.4 (From
top of
floodwall)

5.4 200-year
DWSE

41.0 0.03 [Toe, blanket = 14.7 feet] 0.0 Meets underseepage and through seepage criteria for 200-
year DWSE and HTOL WSE.

1.92 Meets criteria for 200-year
DWSE and HTOL WSE.

NA

8.4 HTOL
WSE

44.0 0.05 [Toe, blanket = 14.7 feet] 0.2 (SM) 1.88
*An increase of 20 percent was applied to two-dimensional average exit gradients to account for three-dimensional effects in Reaches NE-2 and ARS-1.

Table taken from the final GERPD.

Analysis results are for remediated levees.

SECTION 7.0 GEOTECHNICAL EVALUATION RESULTS SUMMARY
20150226_SAFCA_PIR-Addendum1.docx 7-3 Issue Date: 02-2015 Table 7-1 Seepage and Stability Analysis Results.

Reach and
Station for
Analysis
Section
Top of Levee
Elevation
(NAVD88,
approx.
feet)
Landside
Toe
Elevation
(NAVD88,
approx. f
eet)
Levee or
Floodwall
Height
(feet)
Hydraulic
Head (feet)
Flood
Level
Analyzed
Water
Surface
Elevation
(NAVD88,
feet)
Steady State Seepage Analysis Results Landside Slope Stability Analysis Results Average Vertical
Exit Gradient, i [Location, Blanket
Thickness]
Breakout
Above
Landside
Toe (feet)
Comments Minimum
Factor
of Safety
Comments
Reach NAS-ARN-5 (Station 5100+00 to 5112+43, 1243 feet)Station 5100+00 42.5 (Top of the Levee) 45.2 (Top of Floodwall)

37.4 5.1 (From the
top of the levee) 7.8 (From top of floodwall)

2.0 100-year 39.4 0.12 [Toe, blanket = 9 feet] 0.5 (SC) Meets underseepage and through seepage criteria for 100-year, 200-year, and HTOL WSEs.

2.92 Meets criteria for 200-year and
HTOL WSEs

2.7 200-year 40.1 0.17 [Toe, blanket = 9 feet] 0.9 (SC) 2.81 5.7 HTOL 43.1 0.34 [Toe, blanket = 9 feet] 1.5 (SC) 2.37 Station 5110+46 NA (No Levee)

46.5 (Top of Floodwall)

39.6 (Base of Flood Wall)

6.9 (From top of floodwall)

1.3 100-year 40.9 0.18 [Toe, blanket = 7.2 feet] NA (No Levee)
Meets underseepage and through seepage criteria for 100-year, 200-year WSE, and HTOL WSEs. The calculated gradient at the HTOL WSE is only 0.01 higher than the criteria of 0.6. Also, a sensitivity analysis using site-specific hydraulic conductivity testing results indicate this section meets criteria for the HTOL WSE.

NA (No Levee) Not applicable (No levee).

1.8 200-year 41.4 0.24 [Toe, blanket = 7.2 feet] NA (No Levee)
NA (No Levee)

4.8 HTOL 44.4 0.61 [Toe, blanket = 7.2 feet]

0.53 [Toe, blanket = 7.2 feet, Sensitivity with measured Kv=5.3E-05 cm/sec in layer 2 (aquifer)] NA (No Levee)
NA (No Levee)
Reach NAS-ARS-5 (Station 4083+21 to 4110+00, 2679 feet) Station 4090+00 43.1 (Top of the Levee) 44.7 (Top of Floodwall)

35.6 7.5 (From the
top of the levee) 9.1 (From top of floodwall)

3.5 100-year 39.1 0.21 [Toe, blanket = 5.3 feet]

0.24 [4 feet from toe, blanket = 5.1 feet]

1.2 (SC) Meets underseepage and through seepage criteria for 100-year, 200-year, and HTOL WSEs. Sensitivity Analysis Sensitivity: Landside blanket (Layer 2) thickness decreased 0.5 feet by raising the interface of Layers 2 and 3. 100yr, i=0.23 at toe, i=0.26 at 4 feet from toe 200yr, i=0.29 at toe, i=0.30 at 4 feet from toe HTOL, i=0.46 at toe, i=0.46 at 4 feet from toe Sensitivity results meet criteria.

2.10 Meets criteria for 200-year and
HTOL WSEs Sensitivity Analysis: Sensitivity #1: Determine factor of safety using combination circular/non-circular failure mode for 200-yr WSE. 200yr, FOS=2.02 Sensitivity meets criteria. Sensitivity #2: Determine factor of safety using non-circular failure mode for 200-yr WSE. 200yr, FOS=2.24 Sensitivity meets criteria.

4.2 200-year 39.8 0.25 [Toe, blanket = 5.3 feet]

0.27 [4 feet from toe, blanket = 5.1 feet]

1.5 (SC) 2.04

7.2 HTOL 42.8 0.42 [Toe, blanket = 5.3 feet]

0.41 [4 feet from toe, blanket = 5.1 feet]

2.5 (SC) 1.79
Station 4094+00 43.5 (Top of
the Levee) 45.0 (Top of Floodwall)

36.3 7.2 (From the
top of the levee) 8.7 (From top of floodwall)

3.0 100-year 39.3 0.29 [Toe, blanket = 7.8 feet] 1.3 (SC) Meets underseepage and through seepage criteria for 100-year, 200-year, and HTOL WSEs.

2.23 Meets criteria for 200-year and
HTOL WSEs

3.7 200-year 40.0 0.35 [Toe, blanket = 7.8 feet] 1.3 (SC) 2.14 6.7 HTOL 43.0 0.60 [Toe, blanket = 7.8 feet] 3.2 (SC) 1.74 Station 4102+30 43.7 (Top of
the Levee) 45.7 (Top of Floodwall)

39.5 4.2 (From the
top of the levee) 6.2 (From top of floodwall)

0.5 100-year 40.0 0.03 [Toe, blanket = 9.3 feet]

0.01 [20 feet from toe, blanket = 7.2 feet]

0.0 (SC) Meets underseepage and through seepage criteria for 100-year, 200-year, and HTOL WSEs.

3.20 Meets criteria for 200-year and
HTOL WSEs

1.1 200-year 40.6 0.08 [Toe, blanket = 9.3 feet]

0.06 [20 feet from toe, blanket = 7.2 feet]

0.3 (SC) 3.08

4.1 HTOL 43.6 0.26 [Toe, blanket = 9.3 feet]

0.25 [4 feet from toe, blanket = 7.2 feet]

1.1 (SC) 2.56
Table taken from the PIR Addendum 1.Analysis results are for existing levees meeting criteria without requiring remediation.

SECTION 7.0 GEOTECHNICAL EVALUATION RESULTS SUMMARY
20150226_SAFCA_PIR-Addendum1.docx 7-4 Issue Date: 02-2015 Table 7-1 Seepage and Stability Analysis Results.

Reach and
Station for
Analysis
Section
Top of Levee
Elevation
(NAVD88,
approx.
feet)
Landside
Toe
Elevation
(NAVD88,
approx. f
eet)
Levee or
Floodwall
Height
(feet)
Hydraulic
Head (feet)
Flood
Level
Analyzed
Water
Surface
Elevation
(NAVD88,
feet)
Steady State Seepage Analysis Results Landside Slope Stability Analysis Results Average Vertical
Exit Gradient, i [Location, Blanket
Thickness]
Breakout
Above
Landside
Toe (feet)
Comments Minimum
Factor
of Safety
Comments
Station 4108+00 44.2 (Top of
the Levee) 46.6 (Top of Floodwall)

37.7 6.5 (From the
top of the levee) 8.9 (From top of floodwall)

3.1 100-year 40.8 0.31 [Toe, blanket = 6.5 feet] 1.0 (SC) Meets underseepage and through seepage criteria for 100-year, 200-year WSE, and HTOL WSEs. The calculated gradient at the HTOL WSE is only 0.02 higher than the criteria of 0.6. Also, a sensitivity analysis using site-specific hydraulic conductivity testing results indicate this section meets criteria for the HTOL WSE.

2.10 Meets criteria for 200-year and
HTOL WSEs Sensitivity Analysis: Sensitivity #1: Determine factor of safety using combination circular/non-circular failure mode for 200-yr WSE. 200yr, FOS=2.00 Sensitivity meets criteria. Sensitivity #2: Determine factor of safety using non-circular failure mode for 200-yr WSE. 200yr, FOS=2.18 Sensitivity meets criteria.

3.6 200-year 41.3 0.35 [Toe, blanket = 6.5 feet] 1.5 (SC) 2.04 6.6 HTOL 44.3 0.62 [Toe, blanket = 6.5 feet]

0.46 [Toe, blanket = 6.5 feet, Sensitivity with measured Kv=5.8E-05 cm/sec in layer 2 (blanket)]

2.2 (SC) 1.68
Table taken from the PIR Addendum 1.Analysis results are for existing levees meeting criteria without requiring remediation.

PREPARED BY:

CHECKED BY:

ISSUE DATE:

AECOM PROJECT NO
RICH MILLET 60709232
07/15/2024

GEOMETRY AND MATERIAL ZONING FOR BLANKET LAYER CONDITION FIGURE 1 STEAD-STATE SEEPAGE ANALYSIS
REACH NAS-PRS-3
Station 4060+00
(1)
(6)
(2)
(1)
Sheet Pile Wall

SACRAMENTO AREA FLOOD

CONROL AGENCY

NORTH AREA STREAMS

LEVEE IMPROVEMENT PROJECT

WATERSIDE LANDSIDE

YAO ZHANG
(3)
(4)
(5)
(7)
(8)
(2) (9)
(10)
(1)
SEEPAGE ANALYSIS RESULTS – 200 YEAR WSE AT 40.1 FT

AVERAGE GRADIENT

ACROSS BLANKET
PREPARED BY:

CHECKED BY:

ISSUE DATE:

AECOM PROJECT NO
RICH MILLET 60709232
07/15/2024 FIGURE 2 STEAD-STATE SEEPAGE ANALYSIS
REACH NAS-PRS-3
Station 4060+00

SACRAMENTO AREA FLOOD

CONROL AGENCY

NORTH AREA STREAMS

LEVEE IMPROVEMENT PROJECT

YAO ZHANG
= (37.4 - 34.0)
(29.2 - 20.1) = 0.37200 YEAR WSE 40.1 FT
Appendix C
UPRR Stoplog Closure
Arcade Creek South

Appendix D

LEVEE GEOMETRY

CROSS SECTION EVALUATION
American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 1 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx Note:

MTOL = Base Flood Elevation Plus 3' Freeboard
American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 2 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx Note:

MTOL = Base Flood Elevation Plus 3' Freeboard
American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 3 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx Note:

MTOL = Base Flood Elevation Plus 3' Freeboard
American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 4 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx Note:

MTOL = Base Flood Elevation Plus 3' Freeboard
American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 17 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx Note:

MTOL = Base Flood Elevation Plus 3' Freeboard
American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 18 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx Note:

MTOL = Base Flood Elevation Plus 3' Freeboard
Appendix E

AECOM COMPLETION REPORT

WATERSIDE FILL REPLACEMENT

ARCADE CREEK SOUTH LEVEE
STATION 4067+60
AECOM
2020 L Street, Suite 400
Sacramento, CA 95811
tel: 916 414 5800
fax 916 414 1557
www.aecom.com
July 23, 2024
Ms. Becky Money, PE, GE
Supervising Engineer
MBK Engineers
455 University Avenue, Suite 100
Sacramento, CA 95825
Regarding: AECOM Completion Report Waterside Fill Replacement “Final Draft” Arcade Creek – Station 4067+60
Sacramento, California
Dear Ms. Money:

This memo documents the successful completion of the placement of a low permeable soil blanket cover over the existing AT&T Duct Bank on the water side of the south levee of Arcade Creek at approximately Station 4067+60. See Figure 1 in Attachment A for the location of the completed work.

At the request of SAFCA, AECOM prepared the Construction Plans included in Attachment A for the subject earthwork addressing the concern that this duct bank invert crosses the crest of the levee slightly below the 200-year design water surface that could be a source of thorough seepage.

Based upon investigation of the soil covering the duct bank, it was determined that the soil did not have sufficient fine grain material (clay and silt) to adequately reduce seepage through the levee embankment in the area of the duct bank. To remediate this condition AECOM designed an excavation plan to uncover the duct to a depth of 3 feet and then backfill the excavation with a new blanket meeting Title 23 levee fill (see plans in Attachment A). Sources of levee fill borrow materials were investigated at the ECHO Treatment Plant in south Sacramento. Stockpiled waste soils were sampled and tested and found to meet project criteria for low permeable levee fill.

In the spring of 2024, SAFCA placed under contract the North Star Construction and Engineering company to implement the proposed remedial work. Prior to implementation of the work the contractor completed the underground service alert (USA) and utility research for the excavation area which was clearly marked in the field. Pot holing was completed within the excavation area to verify utility locations on 10 June 2024. Mobilization and construction started on 11 June 2024 with the clearing and grubbing of the work areas, followed by excavation of existing soils covering the duct bank in accordance with the project plans (see photos in Attachment B). This was followed by the placing of the ECHO Treatment Plant fill material in the excavated area. The fill material was placed in 6-inch loose lifts and benched into the excavated slope. Fill was compacted with a CAT CP34 or Multiquip Mikasa MTX-70 compactor and achieved the required density of 95% relative