3 7 16 Work Session_Levee Breach Prevention and Preparedness Copyright 2014
City of Dubuque Work Session # 1.
ITEM TITLE: 5:30 PM- Levee Breach Prevention and Preparedness
Activities
SUMMARY: The Engineering staff will conduct a work session with the
City Council on Levee Breach Prevention and
Preparedness Activities.
SUGGESTED DISPOSITION:
ATTACHMENTS:
Description Type
Levee/Flood Breach Prevention and Preparedness- City Manager Memo
MVM Memo
Staff Memo Staff Memo
Levee Presentation Outline Supporting Documentation
THE CITY OF Dubuque
UBE I
erica .i
Masterpiece on the Mississippi 2007-2012-2013
TO: The Honorable Mayor and City Council Members
FROM: Michael C. Van Milligen, City Manager
SUBJECT: Levee/Floodwall Breach Prevention and Preparedness Activities, City
Council Work Session Materials
DATE: February 26, 2016
City Engineer Gus Psihoyos has provided some information related to the
Levee/Floodwall Breach Prevention and Preparedness Activities City Council Work
Session on Monday, March 7, 2016 at 5:30 p.m.
S4-'6�-
MicKael C. Van Milligen
MCVM:jh
Attachment
cc: Barry Lindahl, City Attorney
Cindy Steinhauser, Assistant City Manager
Teri Goodmann, Assistant City Manager
Gus Psihoyos, City Engineer
C)ubuque
THE CI'T'Y OF �,�
DUB E NlAmericaCitV
LI
Masterpiece on the Mississippi 21„,;..2012,2013
TO: Michael C. Van Milligen, City Manager
FROM: Gus Psihoyos, City Engineer
DATE: February 26, 2016
SUBJECT: Levee/Floodwall Breach Prevention and Preparedness Activities,
City Council Work Session Materials
INTRODUCTION
The purpose of this memorandum is to provide materials for the City Council Work Session
scheduled for March 7, 2016 to discuss the City's various levee/floodwall breach prevention and
preparedness activities.
BACKGROUND
The John C. Culver Floodwall floodwall/levee system was designed to protect the City of
Dubuque from Mississippi River floods. It was authorized by the federal Flood Control Act of
1962. It consists of a combination of levees and floodwalls along the entire Dubuque riverfront
from the upstream Lock& Dam 11 to the downstream end of the city near Maus Park.
Construction began in 1968 and was completed in 1973.
Dubuque's "Flood Control System” consists of earthen levees (22,500 ft.) and concrete
floodwalls (7,120 ft.), providing protection against a Mississippi River flood that has a 0.5
percent chance of occurring in any given year. The Flood Control System includes gravity
outlets for discharge into the river at low stages and pumping stations and ponding areas for
use when the Mississippi River is high.
The improvements associated with the John C. Culver Floodwall flood protection system is
operated and maintained by the City of Dubuque with U.S. Army Corps of Engineers (USACE)
oversight.
DISCUSSION
Funded and built by the U.S. Army Corps of Engineers (USACE) and operated and maintained
by the City of Dubuque, the John C. Culver Floodwall flood protection system (Flood Protection
System) protects thousands of properties from Mississippi River flooding. According to the
USACE, the Flood Protection System "has prevented an estimated $103,955,700 in flood
damages as of 2009." And the protection provided has been recognized in the Flood Rate
Insurance Maps published by the Federal Emergency Management Agency (FEMA). The
USACE, City of Dubuque, and FEMA all play roles to ensure that the Flood Protection System
will provide the intended protection when the Mississippi rises.
In exchange for the USACE agreeing to fund and construct the Flood Protection System, the
City of Dubuque agreed to maintain and operate the floodwall system after completion in
accordance with regulations prescribed by the USACE.
The USACE conducts two types of inspections to help ensure the Flood Protection System is
adequately operated and maintained. An Annual Inspection is performed by USACE Rock
Island District employees. The Annual Inspection usually conforms to the following process:
• Joint inspection of the Flood Control System by USACE and City staff;
• USACE provides a report to the City with inspection findings and recommendations;
• Independent inspection and corrective actions are undertaken by the City; and
• City submits a report to USACE outlining actions taken or planned to correct defects
noted in the USACE inspection report.
A Periodic Inspection occurs every five years if federal funding is available. It is usually
performed by a third party hired by the USACE. The Periodic Inspection is more comprehensive
than the Annual Inspection. Dubuque's most recent Periodic Inspection was conducted in 2010
and its findings report issued in March of 2011.
The Federal Emergency Management Agency's role is related to the Flood Rate Insurance
Maps (FIRMs) they publish for Dubuque. The FIRMs identify the individual properties that are
required to carry federally subsidized flood insurance based on their risk of flooding. Dubuque's
Flood Protection System was designed to protect many properties that would be otherwise
damaged due to Mississippi River flooding. The FIRMs recognize this fact identifying the areas
and properties protected by the Flood Protection System and waiving the requirement for these
properties to be covered by flood insurance.
Whenever new FEMA flood insurance rate maps are produced, levees must be evaluated,
effectively"certified" that they still provide protection they claim. This was the case when FEMA
updated the FIRMs for Dubuque in 2011. Levee Certification means that a levee meets federal
standards for design, construction, maintenance and operation to adequately reduce the risk of
flooding.
Certification of Dubuque's Flood Protection System was a two-year process, requiring extensive
engineering analyses and studies. The Public Works, Engineering, and Planning Services
Departments worked with FEMA, the USACE, and engineering consultants to prepare the
necessary documentation for the City Engineer to "certify" Dubuque's Flood Protection System.
Re-certification is anticipated every ten years or when FEMA provides updated FIRMs.
The USACE, FEMA, and City of Dubuque all recognize that Dubuque's Flood Protection System
does not eliminate the risk associated with Mississippi River flooding. While the situation's
surrounding the failure of the levee systems in New Orleans as a result of Hurricane Katrina, it
does serve to remind citizens that levees do fail. Recognizing this reality, the City of Dubuque
set aside funding in FY2014 for the Floodwall Breach Analysis (CIP#7202239). The stated
purpose of the study was to "identify actions that could be taken in the event of a floodwall
failure to reduce the flood and limit property damage."After reaching out to the Rock Island
District of the United States Army Corps of Engineers (District), the City's primary partner when
it comes to the Flood Protection System, the City was informed that the District had been
involved with a similar effort for the City of Muscatine and another was planned for the City of
Cedar Falls. And in August of 2014, the District was able to secure federal funding to prepare a
levee breach analysis for the City of Dubuque. The USACE levee breach analysis was not
initiated because of any known imminent risk of failure to the levee protecting Dubuque, but
instead as an effort to improve emergency planning and communication of the potential risks
associated with the levee.
2
The District created a sophisticated computer model that can predict the depth of inundation,
time to inundation, and inundation paths at critical infrastructure for hypothetical levee breach
scenarios. The main goal of the District's work was to further advance the USACE's new
computer software tool [HEC-RAS 5.0]. But the work also helped to further their mission to
ensure that the public understands the risks of"living behind a levee." The USACE levee breach
analysis serves as a starting point for additional more detailed analysis of evacuation routes,
potential flood hardening, and overall resiliency planning and design.
In 2015, the City hired an engineering consultant to advance the 2-D modeling work started by
the USACE funded through the FY14 Floodwall Breach Analysis appropriation. To date, the
engineering consultant has updated the model with break lines, spatially varied Manning's
roughness coefficients, and inclusion of buildings within the model domain. With the Fiscal Year
2017 budget, non-recurring funds in the amount of$160,000 was requested to provide funding
for an engineering consultant to advance the work. The additional work involves further defining
depth of inundation, time to inundation, and inundation paths at critical infrastructure for
hypothetical levee breach scenarios. It would provide an evaluation of how sensitive the
hydraulic characteristics of the resultant flooding are to different breach locations,
characteristics, and river conditions. This would allow the City an understanding of what might
be done before, during, and after a levee breach to mitigate the threat to human safety/heath
and property.
The Engineering, Planning Services, and Public Works staff will be there to present more
detailed information and lead the discussion. An outline of the presentation is attached.
REQUESTED ACTION
No action is required. This memo is for informational purposes only.
Prepared by Deron Muehring
Attach.
Cc: Teri Goodmann, Assistant City Manager
Don Vogt, Public Works Director
John Klostermann, Street and Sewer Maintenance Supervisor
Laura Carstens, Planning Services Manager
Kyle Kritz, Associate Planner
Randy Gehl, Public Information Officer
Bob Schiesl, Assistant City Engineer
Deron Muehring, Civil Engineer
3
Outline
Presentation to City Council on March 7, 2016
Levee Breach Prevention/Preparedness Activities
1) History of Floodwall/Levee System
a) Why it came to be
i) Flooding (1952 & 1965)
ii) Cost versus benefits
iii) Federal funding
b) When constructed and by whom
c) What the John C. Culver flood protection system consists of
i) Levees
ii) Floodwalls
iii) Pumping facilities
iv) Ponding areas
2) Federal role
a) Funded construction
b) Joint Oversight — USACE & City
i) Review/approve modifications
ii) Annual inspections
iii) Periodic inspections
iv) Encroachments
3) City role
a) Operation - actions taken during flood event
i) Close gates
ii) Operation pump stations
iii) Monitor
b) Maintenance — actions prior to flood event
i) Debris removal
ii) Exercise pumps
iii) Repair/replace pump station elements
iv) Maintain (dredge) ponding areas
v) Maintain culverts through system
c) Replacements & Improvements
i) Gate replacement
ii) Pump replacement
iii) Generators
iv) 10-inch auxiliary pumps
v) Flood Barriers (i.e. HESCO)
d) Budget
i) Operating
ii) CIP
(1) Dredging
(2) Gate replacement
4) Levee/floodwall certification - FEMA
i) Background
(1) Related to flood insurance rate maps
(a) Map of area protected by system
(b) Insurance requirements without certified system
(2) Post-Katrina, local communities served by system must certify
ii) Engineering analysis
(1) Stability analysis
(2) Interior drainage analysis
(3) Condition analysis
5) Levee Breach Study
a) Purpose — empower citizens (living behind a levee)
b) USACE work
i) Build 2D model (depth versus time)
ii) Analysis of 4 breach locations
c) City work
i) Enhance model to create better planning tool
ii) Modifications to evacuation routes
iii) Look closer at how breach might impact critical facilities & infrastructure
(1) Map
(a) Population centers
(b) Utility providers
(c) Infrastructure
(d) Disaster response
iv) Run additional "what if' scenarios
v) Identify best practices and possible improvements that might mitigate flood
damage that could occur during a breach (i.e. backflow prevention).
d) Study Budget
6) On the horizon — USACE Levee Safety Action Classification (LSAC)
7) Discussion/Questions
03/07/2016
Levee/Floodwall Breach
Prevention & Preparedness Activities
Sutton Pool
History of Levee/Floodwall System
Chaplain
Schmitt
Island
East Du.uque, IL
Maus Lake
Port of
Dubuque
ism* Flcs:
NMevee
111111111111111111111
1
03/07/2016
History of Levee/Floodwall System
1941 U.S. Supreme Court ruling confirmed that the U.S. Army
Corps of Engineers could hold back floodwaters with the
Bellevue dam and flood Dubuque's low-lying areas
Flood of April 1951
Photo courtesy of Pictorial Dubuque: Dubuque's Greatest Flood
River crested
at 22.65 feet
Looking NW from 5th & White Streets
2
03/07/2016
Flood of April 1952
Photos courtesy of Pictorial Dubuque: The Floods Return to Dubuque
River crested at 22.70 feet
Looking west from 16th & Sycamore Streets
Looking east down 17th Street from Washington Street
Modest Protections
Dubuque Packing Company
subsequently funded and
built a levee and pumping
station (Bee Branch Station)
to protect its facility
(future) 16th Street
Detention Basin
3
03/07/2016
Modest Protections
In early 1965, aware of imminent flooding, the City constructed
a temporary levee to protect its new Kerper Industrial Park
Photo courtesy of TH Media Archives
3
Modest Protections
City also constructed temporary levees to keep the Iowa -
Illinois Bridge open during the 1965 flood
Photo courtesy of TH Media Archives
4
03/07/2016
Levee/Floodwall System Funding
• 1965 Flood was the turning point — community consensus that
a floodwall was needed
• Federal funds sought — but competing with the Vietnam War
and the Space Race
• Congressman John Culver
instrumental in securing
$11 million in federal funds
Levee/Floodwall System
Construction
• Construction began in June 1968
• Completed in early 1973 — dedicated on
August 4th that year
Image courtesy of TH Media Archives
5
03/07/2016
Dubuque Flood Control System
20,500 feet - Earthen Levees
900 feet - Concrete Floodwall
4 - Pumping Stations
10 - Gatewell Structures
10 - Gated Closures
1- Miter Gated Harbor Closure
2 - Sandbag Closures
Dubuque Flood Control System
System Improvements
• Installed backup power
generators at all 4 pumping
stations
• Increased pumping capacity
at Ice Harbor
• Buried floodwall and
eliminated 3 closure gates
03/07/2016
Joint Oversight: Army Corps & City
Project Agreement Requires:
City will operate and maintain
the flood control system as
required by Title 33, Code of
Federal Regulations.
Joint Oversight: Army Corps & City
Requirements:
• AH project changes be approved by the Corps of Engineers
• Provide staff to aid Corps required inspections
— Annual Inspections
— Periodic Inspections
• Take corrective actions to correct defects found during inspections
• Take corrective actions to permit or eliminate encroachments into the
flood control easements.
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03/07/2016
Joint Oversight: Army Corps & City
Annual Inspection Schedule
• November/December: Joint inspection with Corps
• January: Corps provides inspection report
— January 26, 2016: Levee condition "Acceptable" -- highest rating given
(as defined by Public Law 8-99 project maintenance standards)
• April thru June: Independent inspection/corrective actions
• July: Submit report to the Corps of Engineers
Joint Oversight: Army Corps & City
Periodic Inspections
• 5 years or as funding is available
• Last Periodic Inspection: 2010/2011
8
03/07/2016
City Responsibilities
• Preparation
• Maintenance & Pre -Flood Event
• Operations — Flood Event Action Steps
• Operations — Post Flood Repair
Preparation
Self sufficient in flood emergencies
Adequate stock of flood fighting
equipment
Sandbags: 43,000+
Flood Control Barriers: 20,000 ft.
Plastic sheeting: 1,300 ft.
9
03/07/2016
Maintenance & Pre -Flood Event
Remove debris from levee
Exercise gate closures
Test electric pump motors (5 locations -
11 pumps)
Underwater inspections at Ice Harbor &
Bee Branch gates
Inspect Back-up Power Generators
Inspect Portable Pumps
Operations — Flood Event Action Steps
River Stage Predictions: 14 —16 ft.
• Close 8th St., Bee Branch, Hawthorne
St., & Kerper gates
• Start pumping operations at Bee
Branch and Hawthorne Street
Pumping Stations
• Test Ice Harbor gates and notify
harbor users of likely closures
10
03/07/2016
Operations — Flood Event Action Steps
River Stage Predictions: 17-19 ft
• Close Ice Harbor & Maus Lake gates
• Close Commercial St./4th St. gate
• Close Kilgore Dr. gate
• Set up pumps at 4th St (24 hr. operation)
• Start Pumps at Ice Harbor and draw down
harbor to 10 feet
• Start Pumps at Maus Lake Pumping Station
1
Operations — Flood Event Action Steps
River Stage Predictions: 21— 25 ft.
• Shut off power and remove poles at
American Trust River's Edge Plaza
• Remove ramp and close gate at plaza
• Close South Port gates (3)
• Close gate & install portable pump at
Gavilon site
• Fill 5,000 sandbags for emergency use
r inspections
11
Operations — Flood Event Action Steps
River Stage Predictions: 25 — 30 ft.
• Close gates Koch Dr. & Purina Dr. areas
and set up portable pumps
• Notify Railroads of possible track
closures
• Fill 10,500 sandbags for possible track
closure
03/07/2016
Operations — Flood Event Action Steps
River Stage Predictions: 30 — 33 ft.
• Install sandbag railroad closures at
each end of the levee
• Deploy flood control barriers to
raise height of the levee to prevent
overtopping
12
03/07/2016
Operations — Post Flood Repair
River Stage: 9 ft
• Complete post flood inspection
• Identify necessary repairs and costs
• Request funding assistance from the
Corps (PL 84-99 Program)
• Complete repairs before next flood
season with or without financial
assistance from the Corps of Engineers
1
Flood Control Budget
Public Works Department
• Fiscal Year 2017 Operating Budget $183,424
— Limited budget to cover short time operations and general
maintenance items
• Fiscal Year 2017 Capital Improvement Projects (CIPs)
— Floodwall Post -Flood Repair Program $25,000
— Temporary Flood Control Units $295,000
13
03/07/2015
Levee/Floodwall Certification
Background on FEMA Certification
• Devastation caused by Hurricanes Katrina and Rita:
-- local communities served by levee & floodwall systems must certify
• Related to Flood Insurance Rate Maps and National Flood
Insurance Program
• Certification means flood risk is reduced (not removed)
14
Background on FEMA Certification
03/07/2016
• Devastation caused by Hurricanes Katrina and Rita:
— local communities served by levee & floodwall systems must certify
• Related to Flood Insurance Rate Maps and National Flood
Insurance Program
• Certification means flood risk is reduced (not removed)
Engineering Technical Review
• Satisfied the Corps' hydraulic, geotechnical, mechanical and
electrical design standards
• Satisfied the minimum standards of the National Flood
Insurance Program
US Army Corps of Engineers
15
03/07/2015
Interior Drainage Analysis
• Modeled any flooding greater
than 1 -foot depth in 9 basins.
• Result: no areas in the interior
basins with greater than 1 -foot
of flooding depths.
Seepage and Stability Evaluation
• Meets minimum for Embankment and Foundation Stability
• Identified 3 areas for flood monitoring and response measures
Chaplain
Schmitt
Island
Dubuque Levee &
Floodwall System
Port of
Co;n.suiirtq Engirierrs Dubuque
East Dubuque, IL
16
Protected by Dubuque levee/Flood call
03/07/2016
Flood Insurance Recommended
1. You do not need to live near water to be flooded.
2. Flood damage is not covered by typical property owner's
insurance.
3. Flood insurance is available for buildings and contents.
17
03/07/2016
Dubuque Levee System Breach Analysis
Dubuque Urban Levee
System
Levee Breach Analysis
Rock Island District
Tom Gambucci
Shirley Johnson
Toby Hunemuller
June 15, 2015
BUILDING STRONG®
Levee Risk
Levees are not designed/constructed to a height to
protect against all floods. Therefore, there are residual
risks for inhabitants and structures behind a levee.
Project Goal
Produce products that the City of Dubuque can use to
reduce residual flood risk through planning and
preparation.
For Internal Use Only
36
BUILDING STRONG()
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03/07/2016
Study deliverables
Analysis of failure scenarios, timing, and inundation mapping to
serve as input for stakeholder's emergency preparedness planning,
and selection of evacuation routes and procedures.
The study was not initiated because of any known imminent risk of
failure to the levee protecting the City of Dubuque.
BUILDING STRONG®
Dubuque Urban
Levee System Study
Breach Analysis
Flood Plain Management Services Special Study
Section 206 (PL 86-645) of the 1960 Flood Control Act as Amended
2 -Dimensional Hydraulic Modeling Results
Using HEC -RAS 5.0 Beta (Oct 2014)
BUILDING STRONG®
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03/07/2016
Time to Depth Summary
All events modeled use the Design Event hydrograph,
peak flow 362,000 cfs (approximately 2 ft above the 500 -year flood)
The inundation mapping has been compiled using the best
information available and is believed to be accurate, however, its
preparation required many assumptions. Actual conditions during a flood
event may vary from those assumed, so the accuracy cannot be
guaranteed. The limits of flooding shown should only be used as a
guideline for emergency planning and response actions.
BUILDING STRONG®
History of Levee/Floodwall System
Chaplain
Schmitt
Island
East Du. 'g'que, IL '
Crescent Community
Health Center
20
03/07/2016
21
Arrival Time Results for Levee Breach Scenarios
Time From Breach to 1 ft Water Depth (Hours)
Time From Breach to 2 ft Water Depth (Hours)
Design Event (362,000 cfs), approx 2 ft above the 0.2% (500 -year) annual chance flood
Name
ID Number
Time (Hours)
Crescent Community Health Center
1
4.5
tiA
For Internal Use Only BUILDING STRONG®
42
For Internal Use Only BUILDING STRONG®
41 ,. ofr;c,, u<„ o,,i,
21
Arrival Time Results for Levee Breach Scenarios
Time From Breach to 2 ft Water Depth (Hours)
Design Event (362,000 cfs), approx 2 ft above the 0.2% (500 -year) annual chance flood
Name
ID Number
Time (Hours)
Crescent Community Health Center
1
6.0
tiA
For Internal Use Only BUILDING STRONG®
42
21
03/07/2016
Start of Breach
BUILDING STRONG®
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Arrival Time Results for Levee Breach Scenarios
Maximum Depth at Structure in Feet
Design Event (362,000 cfs), approx 2 ft above the 0.2% (500 -year) annual chance flood
Name
ID Number
Depth (Feet)
Crescent Community Health Center
1
6.6
9791
For Internal Use Only BUILDING STRONG®
43 For Official Use Only
Start of Breach
BUILDING STRONG®
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1 Hour after
Breach
BUILDING STRONG®
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03/07/2016
3 Hours after
Breach
BUILDING STRONGe
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03/07/2016
5 Hours after
Breach
BUILDING STRONG®
8 Hours after
Breach
BUILDING STRONG®
25
03/07/2016
04.pilt (arid
.2ft
MI
ON 4 0 "
MT 4 1I
MS0
- • IP°.
12 Hours after
Breach
BUILDING STRONG®
:p1
MO
—
solow X
14 Hours after
Breach
BUILDING STRONG®
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03/07/2016
16 Hours after
Breach
1_7711
BUILDING STRONG®
Levee/Floodwall System —Breach Analysis
• Next step
— develop a more detailed topographic surface
• Results:
— model has more local relevance
— model suitable to guide local resiliency projects
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03/07/2016
Model Reflects Real -World Conditions
i
Reliance on Model Flooding Predictions
03/07/2016
Levee/Floodwall System —Breach Analysis
• The City invested in the development of a better model
• Now its time to use it to reduce risk to the city of Dubuque
and to facilitate better emergency planning.
1
Levee/Floodwall System —Breach Analysis
Evacuation Planning
29
03/07/2016
Levee/Floodwall System — Breach Analysis
FY2017 Improvement Level Decision Package
• Project Management (Six Months)
• Model Refinement (Sensitivity Analysis)
• Technical Memorandum
• Preliminary Results Workshop
• Alternative Analysis (Mitigation Modeling)
• Mitigation Workshop
ha 1
$ 26,000
$ 52,000
$ 13,000
$ 12,000
$ 45,000
$ 12,000
TOTAL $160,000
Levee Safety Action Classification
US Army Corps of Engineers:
• Began assessing the approximately
2,500 levee systems nationwide
through levee screenings
• Began establishment of a Levee
Safety Action Classification (LSAC)
for each levee
BUILDING STRONG0
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03/07/2016
Levee Safety Action Classification
• Designed to be used as an "apples to apples" comparison of all levees
in the nation
• Results of the screening process and the resulting LSAC will:
— provide an initial quantitative risk estimate
— assist local, state, and federal stakeholders in identification and
prioritization of funding needs
• Preliminary levee screening process and LSAC has been undertaken
• Schedule for additional process steps unknown at this time
BUILDING STRONG®
naccn amr
Levee/Floodwall Breach
Prevention & Preparedness Activities
March 7, 2016
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