Flood Risk Management

Plan Formulation, Project Development, & Stakeholder Issues

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

Structural FRM Measures

Dams Reservoirs Floodwalls Levees Channels Straightening Clearing and snagging Closure structures

Bridge modifications Conveyance

modifications Pumping Channel diversions Beach Nourishment

Structural - Reservoirs

McCook, Ill.Mt. Morris Dam

Center Hill Lake, Tenn. Yatesville Lake, Ky.

Structural - Walls & Levees

Lock Haven, PAFrankfort, KY

Frankfort, KYWest Columbus

Channel Modification Projects

Harlan, KY, tunnels

Minnesota River, MN, diversion

Martins Fork, KY, diversion

River Rouge, MI, channelization

Beach Nourishment, (Before) Miami/Dade

County, FL

Beach Nourishment, (After) Miami/Dade County, FL

NATIONAL FLOOD PROOFING COMMITTEE

US Army Corps of Engineers

FloodProofing

National National Nonstructural/ Flood Nonstructural/ Flood Proofing CommitteeProofing Committee

National National Nonstructural/ Flood Nonstructural/ Flood Proofing CommitteeProofing Committeehttp://www.usace.army.mil/inet/functions/cw/cecwp/NFPC/nfpc.htmhttp://www.usace.army.mil/inet/functions/cw/cecwp/NFPC/nfpc.htm

Nonstructural FRM Measures

Elevation

Relocation

Floodwalls, Levees and Berms

Buyout/Acquisition

Dry Flood Proofing

Wet Flood Proofing

Flooding Warning/Preparedness

Elevating on Extended Foundation Walls

Elevating on Fill

Elevation on Piers, Posts, Piles, or Columns

Piers

Piles

Columns

Posts

Relocation Process

Moving the Structure Evacuate

temporary roadway

Attach structure to trailer

Transport structure to new site

Relocation Process Restoration of Old SiteRestoration 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

Evacuated floodplain area

Ring wall/levee

Ring wall/levee - closure

Ring wall/levee

Waterproof Sealant

Dry Flood Proofing: Methods

Dry Flood Proofing Method:Waterproof Sealant

Elevate Utilities

Wet Flood Proofing

Wet Flood Proofing

Louvre

Let Water In

Flood Warning/Preparedness Components

Flood Threat Recognition System

Warning Dissemination

Emergency Response

Post-Flood Recovery

Continued Plan Management

- Detailed evacuation plans and inundation mapping

- Stream gages with/without remote sensing

- Rain gages with remote sensing

Flood Warning & Emergency Evacuation Plans (FWEEP)

Nonstructural FDR Solutions

FWEEP’s are almost always cost effective and relatively inexpensive

National Flood Insurance Program 44CFR 59-78

Flood Plain Regulation (FDR)

Flood Insurance (Risk Sharing)

Flood Mitigation (FDR)

STREAM CHANNEL

FEMA Definition: 100 Year Floodplain

FLOODWAY FLOOD FRINGEFLOOD FRINGE

______________________________100 year flood _____

Base Flood

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

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.

How - Formulation Strategies

All possible combinations

Measures strategy

Convergent thinking

Divergent thinking

Formulation Strategies

Outputs Maximum damage

reduction

Life cycle costs

Sponsor financial capability

Locally Preferred (LPP)

Change location Flood Resources

Nonstructural (statutory requirement)

Change timing Flood Resources

Change magnitude Flood Resources

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

Nonstructural Opportunities

How do we help this situation?

High groundbehind red line

Town limits

What measures would help?

High groundbehind red line

Levee/Wall?

Detention pond?

Town limits

Channel Modification?Non-Structural Measures?

Evaluation of Existing

Damage Reach

Discharge

Dis

char

ge

Discharge

Probability

Sta

ge

StageD

amag

e

Future Without Conditions

Damage Reach

Discharge

Dis

cha

rge

Discharge

Probability

Sta

ge

Stage

Fill placement to elevate new development

New Development

Attrition of damaged property

Urbanization affects funoff

Channel Modification

Damage Reach

Discharge

Discharge

Dis

char

ge

Probability

Sta

ge

Stage

Dam

age

May induce higher flow rates downstream if storage eliminated

Reservoir / Detention Storage

Damage Reach

Discharge

Discharge

Dis

char

ge

Probability

Sta

ge

Stage

Dam

age

Non-Structural Measures

Damage Reach

Discharge

Discharge

Dis

char

ge

Probability

Sta

ge

Stage

Dam

age

Raise

Floodproof

Levee

Damage Reach

Discharge

Discharge

Dis

char

ge

Probability

Sta

ge

Stage

Dam

age

HEC-FDA S-$ curve

HEC-FDA truncated in EAD

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

0

200000

400000

600000

800000

1000000

1200000

Stage

Dama

ge

020000400006000080000

100000120000140000160000180000

Stage

Disc

harg

e

0

20

40

60

80

100

120

Discharge

Freq

uenc

yFormulation With FDA Model

Walls, leveesFloodproofing

ChannelsClearing & snagging

DamsDetention reservoirs

DISCHARGE FEET FREQUENCY DAMAGES ANNUAL DAMAGES -------- ----- --------------- ------------------ ------------------ 1000's NGVD % % INTERVAL AT STAGE AVERAGE INTERVAL SUMMATION

0 910 99.999999 na $0 na NA3000 911 99.99999 0.000 $0 $0 $0 $06000 912 99.9999 0.000 $0 $0 $0 $08500 913 99.999 0.001 $0 $0 $0 $0

12000 914 99.99 0.009 $0 $0 $0 $015500 915 92 7.990 $0 $0 $0 $018000 916 44 48.000 $0 $0 $0 $022000 917 26 18.000 $25,435 $12,717 $2,289 $2,28926000 918 20 6.000 $44,462 $34,948 $2,097 $4,38629500 919 14 6.000 $60,830 $52,646 $3,159 $7,54534000 920 10 4.000 $69,770 $65,300 $2,612 $10,15738000 921 7 3.000 $86,980 $78,375 $2,351 $12,50842500 922 5 2.000 $118,074 $102,527 $2,051 $14,55948000 923 4.7 0.300 $144,044 $131,059 $393 $14,95252500 924 3.7 1.000 $152,355 $148,200 $1,482 $16,43458000 925 2 1.700 $160,326 $156,340 $2,658 $19,09263000 926 1.6 0.400 $168,262 $164,294 $657 $19,74970500 927 1.4 0.200 $176,062 $172,162 $344 $20,09379500 928 1.2 0.200 $183,964 $180,013 $360 $20,45390000 929 0.9 0.300 $191,832 $187,898 $564 $21,017

102000 930 0.65 0.250 $199,359 $195,596 $489 $21,506112000 931 0.5 0.150 $207,432 $203,396 $305 $21,811128000 932 0.38 0.120 $215,266 $211,349 $254 $22,064142000 933 0.3 0.080 $225,621 $220,443 $176 $22,241157000 934 0.22 0.080 $227,877 $226,749 $181 $22,422

EADCalculation for with projectcondition

Where do we begin in formulation?

High groundbehind red line

Levee/Wall?

Detention pond?

Town limits

Channel Modification?Non-Structural Measures?

First or Last?

High groundbehind red line

Levee

Detention pond

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.)

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

-$15M$85M$100MChannel

$20M$80M$60MLevees/Walls

-$20M$20M$40MPond

$10M$40M$30M Non-Structural

Measure NED Cost NED Benefit Net NED Benefit

Initial Formulation (we have only just begun)

And we look at it all again - Reformulation

First or last positioning of measures

Dependencies

Combinability

Incremental Analysis

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.”

Another Example - What’s An Increment?

High groundbehind red line

Reach 1

Reach 2

Reach 3

Levee alignment

Levee tie-back options

Town limits

Separable Increments of a Flood Damage Reduction Plan

Plan Increment NED CostsNED

BenefitsNet NED Benefits

Levee A (1) $21M $20M -$1M

Levee B (1&2) $40M $70M $30M

Levee C (1,2 &3) $60M $80M $20M

Separable Increments – Did we miss an opportunity the first time?

Plan Increment NED CostsNED

BenefitsNet NED Benefits

Levee D (2) $21M $50M $29M

Levee E (3) $20M $10M -$10M

Levee F (2 &3) $39M $60M $21M

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

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

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?

Flood Protection Levee Lock Haven, PA

Do you think this property could be affected?

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)

Sponsors’ Old RoleSponsors’ Old Role Sponsors’ Old RoleSponsors’ Old Role Prior to 1986:

Not as politically active

Uninvolved in project development

No cost sharing other than LERRD’s

Sponsors’ Changing RolesSponsors’ Changing Roles Sponsors’ Changing RolesSponsors’ Changing Roles Today’s 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.

Sponsors Political ActivitiesSponsors Political ActivitiesSponsors Political ActivitiesSponsors 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)

Actively building state and local coalitions

Campaigning for tight state revenues

Working closely with Congressional Delegations

Actively participating in national associations

Engaging ASA(CW)

Greater Involvement in Project Greater Involvement in Project DevelopmentDevelopmentGreater Involvement in Project Greater Involvement in Project DevelopmentDevelopment

- 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

Greater Involvement in Project Greater Involvement in Project DevelopmentDevelopmentGreater Involvement in Project Greater Involvement in Project DevelopmentDevelopment 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

Demanding Faster, Better, CheaperDemanding Faster, Better, CheaperDemanding Faster, Better, CheaperDemanding Faster, Better, Cheaper

Section 203 WRDA 96

– If feasibility study cost increases greatly after the FCSA has been signed, the sponsor’s incremental share can be delayed until after project construction or 5 years after the Chief of Engineers’ report is issued.

Reconnaissance Studies

Equal TreatmentEqual TreatmentEqual TreatmentEqual Treatment

- Regional consistent analysis

- Equal application of policies

- In-kind credit Crediting for construction related activities now allowed under

Section 2003 of WRDA 2007!!

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.