1 

# ENGINEERING AND

C ONSTRUCTION 

# B ULLETIN

No. 2014

- 2 Issuing Office: CECW

- C E Issued: 5 M a r 2 0 1 4 Expires: 5 M a r 2 0 1 6

Subject: Interim Risk Reduction Measure s (IRRM s ) for Levee Safety

Applicability : Dir ective and Guidance

. The US Army Corps of Engineers ( USACE ) will use

this directive and guidance for all levee systems in the USACE Levee Safety Program , which

includes t hose 1) USACE operated and /or maintained; 2) F ederally authorized, typically USACE

co nstructed

, and locally operated and maintained; and 3) locally constructed and locally operated

and maintained, but have been accepted into the USACE Rehabilitation and Inspection Program (RIP)

. Content of this Engineering and Construction Bulletin (ECB) will be incorporated into the future Levee Safety Program Engineer Circular (EC).

1. Introduction

I nterim R isk R eduction M easures (IRRMs) are actions to reduce inundation risks posed by a levee system that has identified levee safety issues while more long

- term and comprehensive inundation risk reduction and management solutions are being pursued

. “Inundation risk” is

defined as the likelihood and consequences that may arise from inundation of a leveed area. For the USACE Levee Safety Program, fou r inundation scenarios have been adopted as defined below in Figure 1. Many IRRM s are good practice for levee operators and maintainers regardless of the levee condition

. It is important to understand that IRRM s represent an important step in an ongoing adaptive risk management process that recognizes the dynamic

nature of sources of inundation risk

. In establishing IRRM s , the prevention of loss of life is

paramount , followed by prevention of high economic or environmental losses. T he IRRM P lan (IRRMP) is intended to reduce the probability and consequences of inundation risk of the leveed

area from the four inundation scenarios . These four scenarios are to be addressed in the IRRMP.

Figure 1. Inundation ScenariosECB No. 2014

- 2 Subject: Interim Risk Reduction Measures (IRRMs) for Levee Safety

2 2

. When to Develop and Implement an I nterim R isk R eduction M easures P lan (IRRMP)

The development and implementation of the IRRMP is “triggered” for levee systems that have the potential for loss of life and/ or high economic or environmental consequences . This can arise from the occurrence of a flood event that exposes weaknesses in the levee system or specific levee safety acti vities that indicate a need for additional risk reduction measures beyond ordinary operations and maintenance. Those triggers include

, but are n ot limited to

, the following :

a. Routine, Periodic or S pecial I nspection s that indicate operation, maintenance and/or
performance concerns.

b. Flood events , emergencies or incidents revealing performance issues with levees (e.g.
seepage, instability, erosio n, etc

. that could threaten levee integrity)

.

c. R isk assessments , such as Levee Screening s or other types, which indicate safety

issues (i.e. L evee Safety A ction C lassification (LSAC) I, II or III)

. d. Deviations to an approved water control plan to reduce potential consequences.

e. System

- w ide Improvement Framework (SWIF) request by a levee sponsor

. Reference Memorandum CECW

- H S , “ Policy for Developmen t and Implementation
of System

- W ide Improvement Framework s (SWIFs) ” dated 29 Nov 2011.

f. I

- wall evaluations that did not pass the P hase II criteria

. Reference “ Phase II Interim
Guidance for Evaluating Existing I

- Walls ” dated 25 Oct 2006.

3

. Interim Risk Reduction Measures Plan (IRRMP) Conten t

T he general content of the IRRMP should include the following:

a. Overall levee system description and p urpose. Include the National Levee Database (NLD) identification number.

b. Overview of identified potential failure modes associated with the four inundation

scenarios in Figure 1

.

c. General consequences associated with each identified potential failure mode as associated with the four inundation scenarios

. d. Structural and nonstructural IRRM alternatives , examples are in P aragraphs 5 and 6, considered to reduce the probability of inundation or consequences in the leveed areas

associated with the four inundation scenarios

.

e. General discussion of potential consequences and impact s on project purpose,

environmental considerations , and economic s associated with the IRRM s , both positive and negative.

f. Recommended I RRM s and risk informed justification for each recommended

IRRM.

g. Schedules and costs associated with implementation of IRRM recommendations.

h. Schedule and costs associated with a more detailed risk assessment

, if needed

, to
better evaluat e I RRM s

.ECB No. 2014

- 2 Subject: Interim Risk Reduction Measures (IRRMs) for Levee Safety

3 i. C ommunic ation p lan ( i nternal and e xternal)

. The plan shall specifically address communication with all responsible, affected, and interested stakeholders , including the public

.

4. Formulation and Prioritization F actors for I nterim R isk R eduction M easure s (IRRM s )

In formulating and prioritizing IRRM s , it must be kept in mind that each levee system has its own unique attributes that have to be addressed on a case by case basis using expert judgment. The following questions sh ould be considered when determ ining appropriate IRRMs :

a. How will the probability of inundation of the leveed area and the associated

c onsequence s be reduced using structural and nonstructural measures ?

b. Is it ensured that implementation of the IRRM will not increase the life safety risks at any time?

c. Have the IRRMs been assessed for potential adverse impacts to the levee system, including the areas upstream and downstream of the levee system?

d. D oes the IRRM i ncreas e the level of confidence that any changes associated with the

levee sa fety issue (failure mode) will be promptly detected ?

e. D oes the IRRM i ncreas e the confidence that emergency management agencies will be notified promptly when a levee safety issue is detected?

f. D oes the IRRM i ncreas e the warning time and effectiveness of eva cuation of the population at risk ?

g. Does the IRRM r educ e the probability of the initiating load ( for example, if adjusting

an upstream reservoir water control plan

- discuss the consequences of changing the reservoir water control plan ) ?

h. Does the IRRM p rese rv e the public trust and address stakeholder issues ?

i. Is the degree of confidence or uncertainty in understanding the scope of the problem

and effectiveness of the interim solution improved? j. Can the IRRM be incorporated into permanent solutions ?

k. Are there i mpact s to the authorized project purposes or other project benefits ?

l. Do the recommended IRRMs m aximiz e cost effectiveness ?

m. Has the recommended IRRMs considered any social disruption and environmental impacts ?

5

. Examples of N onstructural Interim Risk Red uction Measures (IRRMs)

a. Develop or update a levee system

- specific Emergency Preparedness P lan ( EPP ) that reflects system

- specific risks and includes emergency exercises that are appropriate
for the risk involved. A coordinated EP P addresses who, what, when and how the flood warning and emergency response will be executed

. The EP P should include an explanation of flood warning procedures, emergency notification, evacuation routes, trigger elevations, monitoring, detection and flood fighting. The EP P sh ould also include inundation mapping that illustrate consequences of potential failure mode(s).

The EP P should describe the actions by the entity responsible for levee system operation s and maintenance in the event of a flood or hurricane, earthquake or na turalECB No. 2014

- 2 Subject: Interim Risk Reduction Measures (IRRMs) for Levee Safety

4 disaster type emergen cy. The EP P document should be comple mentary to the Federal Emergency Management Agency (FEMA) All Hazards Mitigation Plan requirement and the Comprehensive Preparedness Guide 101

. See also the US Army Corps of Engineers; “ General Guidelines for Comprehensive Flood Warning/Preparedness
Studies” dated October 1988.

b. Develop specific response plans with specific “trigger” conditions to activate plans. For example, use stream gages, instrumentation and monitor visual indicat ors as “trigger points ” or threshold limits t o initiate more urgent or emergency response. This includes contingency plans or “what’s next type planning” if initial actions prove
ineffective.

c. Conduct appropriate emergency exercises that plan for a range of failure scenarios (including the combined effects of multiple failure modes and different timing of detection). Train existing and/or additional personnel for prompt and effective

emergency response . E xercises should include setting closures on a rout ine basis.

d. Pre

- position emergency supply contracts or stockpile emergency materials, such as, rock, sand, sand bags, emergency bulkheads, or other operating equipment or supplies

.
e. Consider temporary deviations to upstream reservoirs water control plan wit hin existing authorities and policies to reduce the potential impact of known levee

deficiencies. Follow appropriate guidance to obtain approval of deviations.

f. Improve and/or increase inspection and monitoring pre

- flood event, during and after

the flood ev ent to detect evidence of worsening conditions. M ap and document levee system performance. For example

, identify seepage areas and the related water level

when the seepage started. Use this information to guide repairs and pre

- flood preparation for fut ure events

. g. Conduct appropriate engineering investigations and analysis to confirm potential

failure modes.

h. Adapt local National Levee Database processes to accommodate use during

emergency response. i. Co llaborate with federal, state and local agencies, including the N ational W eather

S ervice, FEMA, and state and local Emergency Management Agencies (EMA s )

. More specifically, ensure collaboration with state Hazard Mitigation Officers and state National Flood Insurance Program (NFIP) coordinators. Work wit h existing interagency teams when available. j. Work with the local communities to promote flood mitigation and emergency response. Inform them of opportunities and resources available to complete activities that reduce risk and provide reduction in NFIP pr emiums through FEMA ’s

C ommunity R ating S ystem and other programs ( www.fema.gov ).

k. Create and implement a communication plan to a ctively advise people about the levee condition and potential inundation risk, flood insurance availability and EP P

measures. Ensure information about flood insurance, flood risk, floodplain
management, and evacuation is readily available, for example, through direct mailings, community events, community website s and social m edia, local television and print media, and at the local library.

l. Enact and enfo rce regulations that exceed FEMA’s NFIP minimum standards.ECB No. 2014

- 2 Subject: Interim Risk Reduction Measures (IRRMs) for Levee Safety

5 m. Prepare, adopt, implement, evaluate, and update a comprehensive floodplain management plan , which may include zoning

. A cquire, relocate, or retrofit existing buildings and maintain drainage ways and retention basins.

n. Reinforce landward critical facilities (e.g., medical and emergency services).

o. Additional information on nonstructural alternatives can be found o n the USACE National Nonstructural Floodproofing Committee (NFPC) website. Link is as

follows: http://www.nwo.usace.army.mil/nfpc/

.

6

. Examples of S tructural Interim Risk Reduction Measures (IRRMs)

a. Isolate problem area ( for example construct sub

- levee around failed gravity drain(s)

or other levee feat ure to reduce head differential ).

b. Construct or improve seepage control measures to re tard seepage and reduce uplift,

such as toe drains, relief wells, riverside or landside seepage control blankets, or shallow cutoff trench es

.

c. Implement a target grout program specifically for suspected problem area(s) to slow

seepage.
d. Increase resilienc e to overtopping.

e. Increase erosion protection at water side toe where necessary.
f. Lower levees along the downstream perimeter until the levee can safely withstand design water levels (this may result in more frequent interior flooding).

g. Construct landside stability

- berm to strengthen weak areas.

h. Evaluate internal drainage features, such as ponding areas, and consider alternatives such as additional pumps, to address potential issues.

Note: Structural measures may require S ection 408 approval processes to be followed for federally authorized

- locally operated and maintained levee systems

.

7

. USACE Operated and /or Maintained Levee Systems

USACE d istricts that operate and/ or maintain levee systems that require IRRMs shall develop the levee system specific IRRMP. The d istrict is to implement the IRRMs for all h igh

c onsequences levee systems as aggressively as possible and preferably prior to the next flood season. District IRRMPs shall be approved by the d istrict Levee Safety Officer (LSO) and copie s furnished the Major Subordinate Command (MSC) LSO. Changes to the IRRMP shall be

for mally approved by the d istrict LSO and furnished to the MSC LSO

. IRRMs that include deviations in water control operations should follow normal processes and guidance to obtain approval of the deviation. Within 90 days of approval of t he IRRMP, the d istrict shall develop and implement a communication plan that is coord inated through the appropriate p ublic a ffairs offices at the MSC and HQUSACE as needed

. Funding for IRRMP s preparation and implementation of IRRM s for USA CE operated and / or maintained levees will be from the general O perations and M aintenance account or project specific appropriations, if applicable

.ECB No. 2014

- 2 Subject: Interim Risk Reduction Measures (IRRMs) for Levee Safety

6 8

. Federally Authorized

- Local ly Operated and Maintained Levee Systems and Non

Federal Levee Systems

For the F ederally a uthorized

- locally operated and maintained levee systems and non

- F ederal levee systems in the USACE Levee Safety Program, d evelopment and implementation of

IRRMP s will be the levee sponsors’ decision

. Based on information from the L evee S afety

P rogram activities as described in Paragraph 2, USACE will advise the levee sponsors of identified levee safety issues and recommend the need for IRRMs. It is ultimately the responsibility of the levee sponsor to develop and implement the IRRMs. USACE d istricts may use levee safety funding (Inspection of Completed Works or Flood Control and Coastal Emergencies (FCCE) accounts ) to advise l evee sponsors in the development of their IRRMP

. In addition, p otential programs for joint collaboration of IRRMPs include the Silver Jackets Program; Planning Assistance to the States (PAS); and Floodplain Management Services (FPMS).

9. The implementation point

- of

- contact for this action is the d istrict L evee Safety P rogram
M anager (LSPM) . The HQ technical proponent is Ms. Tammy Conforti, HQUSACE LSPM,

202

- 761

- 4649

.

/ / S / /

J AMES C. D ALTON

, P.E. , SES Chief, Engineering and Construction Division

Directorate of Civil W orks