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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. 7 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() 18 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® 19 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® 22 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® 22 03/07/2016 1 Hour after Breach BUILDING STRONG® 23 03/07/2016 3 Hours after Breach BUILDING STRONGe 24 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® 26 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 27 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 30 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 31