Flood Risk Management

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Flood Risk Management

• Plan Formulation, Project Development,
  Stakeholder Issues

2
Flood Risk Management Measures

• Structural measures
• Modify flood behavior
• Dams and reservoirs, levees, walls, diversion
  channels, bridge modifications, channel
  alterations, pumping, and land treatment
• Nonstructural measures
• Modify damage susceptibility
• Flood warning and preparedness Evacuation and
  relocation National Flood Insurance Program
  (NFIP) Flood proofing

3
Structural FRM Measures

• Dams
• Reservoirs
• Floodwalls
• Levees
• Channels
• Straightening
• Clearing and snagging
• Closure structures

• Bridge modifications
• Conveyance modifications
• Pumping
• Channel diversions
• Beach Nourishment

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Structural - Reservoirs
Mt. Morris Dam
McCook, Ill.
Yatesville Lake, Ky.
Center Hill Lake, Tenn.
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Structural - Walls Levees
Lock Haven, PA
Frankfort, KY
Frankfort, KY
West Columbus
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Channel Modification Projects
Minnesota River, MN, diversion
Martins Fork, KY, diversion
Harlan, KY, tunnels
River Rouge, MI, channelization
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Beach Nourishment, (Before) Miami/Dade County, FL
Beach Nourishment, (After) Miami/Dade County, FL
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National Nonstructural/ Flood Proofing Committee
http//www.usace.army.mil/inet/functions/cw/cecwp/
NFPC/nfpc.htm
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Nonstructural FRM Measures

• Elevation
• Relocation
• Floodwalls, Levees and Berms
• Buyout/Acquisition
• Dry Flood Proofing
• Wet Flood Proofing
• Flooding Warning/Preparedness

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Elevating on Extended Foundation Walls
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Elevating on Fill
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Elevation on Piers, Posts, Piles, or Columns
Piers
Posts
Columns
Piles
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Relocation Process

• Moving the Structure

• Evacuate temporary roadway
• Attach structure to trailer
• Transport structure to new site

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Relocation Process Restoration of Old Site

• Plan must include a new use for the evacuated
  floodplain
• Demolish and remove foundation and pavement
• Disconnect and remove all utilities
• Grading and site stabilization

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Evacuated floodplain area
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Ring wall/levee
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Ring wall/levee - closure
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Ring wall/levee
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Dry Flood Proofing Methods
Waterproof Sealant
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Dry Flood Proofing Method Waterproof Sealant
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Wet Flood Proofing
Elevate Utilities
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Wet Flood Proofing
Let Water In
Louvre
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Flood Warning/Preparedness Components

• Flood Threat Recognition System
• Warning Dissemination
• Emergency Response
• Post-Flood Recovery
• Continued Plan Management

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Nonstructural FDR Solutions
Flood Warning Emergency Evacuation Plans (FWEEP)
- Detailed evacuation plans and inundation
mapping - Stream gages with/without remote
sensing - Rain gages with remote sensing
FWEEPs are almost always cost effective and
relatively inexpensive
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National Flood Insurance Program 44CFR 59-78

• Flood Plain Regulation (FDR)
• Flood Insurance (Risk Sharing)
• Flood Mitigation (FDR)

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FEMA Definition 100 Year Floodplain
______________________________?100 year flood
_____
Base Flood?
STREAM CHANNEL
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Structural and Nonstructural Measures

• Structural measures keep the floods away from
  resources in the floodplain

• Nonstructural measures keep the resources away
  from floods in the floodplain

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Basic Formulation Strategy

• The basic formulation strategy is to formulate to
  meet each of your planning objectives without
  violating any constraints.
• Every iteration of the formulation step must
  employ this basic strategy.

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How - Formulation Strategies

• All possible combinations
• Measures strategy
• Convergent thinking
• Divergent thinking

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Formulation Strategies

• Nonstructural (statutory requirement)
• Change timing
• Flood
• Resources
• Change magnitude
• Flood
• Resources

• Outputs
• Maximum damage reduction
• Life cycle costs
• Sponsor financial capability
• Locally Preferred (LPP)
• Change location
• Flood
• Resources

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Nonstructural Opportunities

• New Uses of the Evacuated Flood Plain
• Ecosystem Restoration
• Recreation
• Spillover Benefits
• Water Quality Improvement
• E.O. 11988
• NFIP Regulations
• Mitigation of Adverse Effects of Structural
  Projects

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How do we help this situation?
High ground behind red line
Town limits
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What measures would help?
Detention pond?
Channel Modification?
Non-Structural Measures?
High ground behind red line
Town limits
Levee/Wall?
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Evaluation of Existing
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Future Without Conditions
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Channel Modification
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Reservoir / Detention Storage
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Non-Structural Measures
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Levee
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FDA Model Evaluates Measures

• Mathematical models are used to evaluate the
  impacts of alternatives for flood damage
  reduction
• The Corps Flood Damage Assessment (FDA) model of
  expected annual damage estimation is the
  preferred method of modeling the effects of
  formulated plans
• Developed and Maintained at HEC Specific
  training is available on the FDA model

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Formulation With FDA Model
Walls, levees Floodproofing
Channels Clearing snagging
Dams Detention reservoirs
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EAD Calculation for with project condition
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Where do we begin in formulation?
Detention pond?
Channel Modification?
Non-Structural Measures?
High ground behind red line
Town limits
Levee/Wall?
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First or Last?
Detention pond
High ground behind red line
Levee
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Dependencies

• Flood damage reduction plans often comprise
  several measures
• Some measures may require implementation of other
  measures in order to function properly
• Interior drainage measures (pump stations and/or
  ponding areas) with levees/floodwalls
• Warning system, operations manual, or FWEEP when
  plans have closure structures requiring human
  intervention (put the sand bag in the slot, flip
  the switch on the gate motor power control, etc.)

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Combinability

• Flood damage reduction plans often comprise
  several increments
• More often flood damage reduction plans have
  measures that can be combined in many ways,
  shapes, and sizes to achieve NED

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Initial Formulation (we have only just begun)
Measure NED Cost NED Benefit
Net NED Benefit
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And we look at it all again - Reformulation

• First or last positioning of measures
• Dependencies
• Combinability
• Incremental Analysis

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Increment Defined

• An increment is any part of a plan that can be
  eliminated without jeopardizing the proper
  function of the remaining parts of the plan.
• Thus, different levels of project performance are
  not increments.
• WRDA 1986 Definition of Separable Element.
  For purposes of this Act, the term
  "separable element" means a portion of a
  project-- (1) which is physically separable from
  other portions of the project and (2) which--
  (A) achieves hydrologic effects, or (B) produces
  physical or economic benefits, which are
  separately identifiable from those produced by
  other portions of the project.

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Another Example - Whats An Increment?
Levee alignment
Reach 1
Levee tie-back options
Reach 2
High ground behind red line
Town limits
Reach 3
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Separable Increments of a Flood Damage Reduction
Plan
Plan Increment NED Costs NED Benefits Net NED Benefits
Levee A (1) 21M 20M -1M
Levee B (12) 40M 70M 30M
Levee C (1,2 3) 60M 80M 20M
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Separable Increments Did we miss an opportunity
the first time?
Plan Increment NED Costs NED Benefits Net NED Benefits
Levee D (2) 21M 50M 29M
Levee E (3) 20M 10M -10M
Levee F (2 3) 39M 60M 21M
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Identifying the NED Plan

• Without-project damages
• With project damages
• Benefits are damages reduced
• Net benefits are benefits less project costs
  (total life cycle costs, including environmental
  mitigation)
• Compare across project scales and between
  alternatives to determine plan that yields
  greatest NED benefits
• Decision-makers always have the final say

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Environmental Consequences

• Flooding is natural flood damage reduction is
  not
• Flood damage reduction measures can have
  environmental consequences
• Some are intended, some are not
• Some are anticipated, some are not
• Some are beneficial, some are adverse
• Unanticipated, unintended consequences may be the
  worst type

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Flood Plain Management Issues

• Induced flooding is not the NED issue
• Induced damages are the issue
• Avoiding or mitigating for induced damages are
  part of project costs and must be considered in
  plan formulation
• Induced flooding is an NFIP/EO 11988 issue that
  must be disclosed in the documentation

Where does the water go?
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Flood Protection Levee Lock Haven, PA
Do you think this property could be affected?
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FEMA and NED Formulation Issues

• National Flood Insurance Program participation
  assumed
• FEMA coordination essential and a matter of
  policy
• FEMA buyout land restrictions on Corps measures
• Locally desired protection (especially 100-year)

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Sponsors Old Role

• Prior to 1986
• Not as politically active
• Uninvolved in project development
• No cost sharing other than LERRDs

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Sponsors Changing Roles

• Todays Sponsors are
• Very politically active
• In many cases technically capable of
  accomplishing work without COE support
• Actively involved in project development
• Demanding faster, better, cheaper
• Want special application of policies for their
  projects.

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Sponsors Political Activities

• Actively building state and local coalitions
• Campaigning for tight state revenues
• Working closely with Congressional Delegations
• Actively participating in national associations
• Engaging ASA(CW)

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Greater Involvement in Project Development

• - Integral member of study team
• - Performing more in-kind services
• - Meeting often with Corps team
• - In on major study changes
• - Will call and visit HQ quickly

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Greater Involvement in Project Development

• Congress provided sponsors authorities to conduct
  planning, design and construction of project.
• Section 203 WRDA 86 - study deep draft navigation
  
• Section 204 WRDA 86 - design and construct deep
  draft navigation
• Section 303 WRDA 90 - construct small navigation
• projects
• Section 206 WRDA 92 - construct shoreline
  protection projects
• Section 211 WRDA 96 - construct flood control
  project
• Section 2003 WRDA 07 credits for materials and
  services provided for design and/or construction

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Demanding Faster, Better, Cheaper

• Section 203 WRDA 96
• If feasibility study cost increases greatly after
  the FCSA has been signed, the sponsors
  incremental share can be delayed until after
  project construction or 5 years after the Chief
  of Engineers report is issued.
• Reconnaissance Studies

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Equal Treatment

• - Regional consistent analysis
• - Equal application of policies
• - In-kind credit
• Crediting for construction related activities now
  allowed under Section 2003 of WRDA 2007!!

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Take Away Points

• Plan formulation is the art of creating plans to
  address the objectives and constraints related to
  flood damage reduction problems and opportunities
• In developing plan formulation strategies, you
  need to understand the basic policies affecting
  plans for flood damage reduction improvements.
• Breakpoints in costs are especially important to
  formulation and associated costs need to be
  included in the analysis
• While a study may recommend a locally preferred
  plan, the NED Plan establishes the limit on the
  Federal investment.