Docstoc

Session 8

Document Sample
Session 8 Powered By Docstoc
					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                  Bridge modifications
 Reservoirs            Conveyance
 Floodwalls             modifications
 Levees                Pumping
 Channels              Channel diversions
 Straightening         Beach Nourishment
 Clearing and
  snagging
 Closure structures
           Structural - Reservoirs




                           Mt. Morris Dam
  McCook, Ill.




Center Hill Lake, Tenn.     Yatesville Lake, Ky.
                 Structural - Walls & Levees




      Lock Haven, PA
                                     Frankfort, KY




Frankfort, KY
                          West Columbus
          Channel Modification Projects

                                    Minnesota River, MN, diversion




Martins Fork, KY, diversion




                                        Harlan, KY, tunnels
  River Rouge, MI, channelization
Beach Nourishment, (Before)   Beach Nourishment, (After)
  Miami/Dade County, FL        Miami/Dade County, FL
National Nonstructural/
    Flood Proofing
      Committee
http://www.usace.army.mil/inet/functions/cw/cecwp/NFPC/nfpc.htm
                                                 US Army Corps of Engineers




                                                Flood
                                                Proofing
                                            NATIONAL FLOOD PROOFING COMMITTEE
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




               Pier
                s                       Posts

                      Columns




      Piles
Relocation Process
Moving the Structure
            Evacuate
             temporary roadway
            Attach structure to
             trailer
            Transport structure
             to new site
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
Evacuated floodplain area
Ring wall/levee
Ring wall/levee - closure
Ring wall/levee
 Dry Flood Proofing: Methods




Waterproof Sealant
Dry Flood Proofing
Method:
Waterproof Sealant
Wet Flood Proofing

Elevate
Utilitie
s
Wet Flood Proofing

Let Water In




            Louvre
Flood Warning/Preparedness Components

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

                 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)
      FEMA Definition: 100 Year Floodplain


  FLOOD FRINGE                   FLOODWAY             FLOOD FRINGE




______________________________100 year flood _____

                                         Base
Flood




                                                STREAM CHANNEL
Structural and Nonstructural
Measures
 Structural measures      Nonstructural
  keep the floods away      measures keep the
  from resources in the     resources away from
  floodplain                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                    Nonstructural (statutory
    Maximum damage           requirement)
     reduction
                             Change timing
    Life cycle costs
                                Flood
 Sponsor financial             Resources
  capability
                             Change magnitude
 Locally Preferred (LPP)       Flood
 Change location               Resources
    Flood
    Resources
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
How do we help this situation?




High ground                      Town limits
behind red line
What measures would help?

                                             Detention pond?




                  Non-         Channel Modification?
                  Structural
High ground       Measures?
                                                 Town limits
behind red line
                                  Levee/Wall?
            Evaluation of Existing


                          Damage Reach
Discharge




                                                   Damage
                               Stage




            Probability
                                       Discharge            Stage
                       Future Without
                       Conditions


                                  Damage Reach




            Urbanization                       Fill placement to elevate            New Development
            affects funoff                     new development
Discharge




                                                                           Damage
                                       Stage




                                                                                                  Attrition of damaged
                                                                                                  property




                    Probability
                                                  Discharge                                    Stage
             Channel Modification


                               Damage Reach
Discharge




                                                               Damage
                                           Stage




                   Probability
                                                   Discharge            Stage
        May induce higher flow rates
        downstream if storage eliminated
Reservoir / Detention Storage


                     Damage Reach
 Discharge




                                                 Damage
                             Stage




             Probability
                                     Discharge            Stage
       Non-Structural Measures


                    Damage Reach
Discharge




                                                Damage
                            Stage




                                                         Floodproof

                                                                Raise




            Probability
                                    Discharge                 Stage
                              Levee


                    Damage Reach




                                                         HEC-FDA truncated
                                                         in EAD
Discharge




                                                Damage
                            Stage




                                                           HEC-FDA S-$ curve




            Probability
                                    Discharge                 Stage
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
               Formulation With FDA Model
Channels                          Walls, levees
Clearing & snagging               Floodproofing




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

         0      910 99.999999     na              $0     na                NA          EAD
      3000      911 99.99999        0.000         $0         $0       $0          $0   Calculation
      6000      912   99.9999       0.000         $0         $0       $0          $0
      8500      913     99.999      0.001         $0         $0       $0          $0
                                                                                       for with
     12000      914      99.99      0.009         $0         $0       $0          $0   project
     15500      915          92     7.990         $0         $0       $0          $0   condition
     18000      916          44    48.000         $0         $0       $0          $0
     22000      917          26    18.000    $25,435    $12,717   $2,289      $2,289
     26000      918          20     6.000    $44,462    $34,948   $2,097      $4,386
     29500      919          14     6.000    $60,830    $52,646   $3,159      $7,545
     34000      920          10     4.000    $69,770    $65,300   $2,612     $10,157
     38000      921           7     3.000    $86,980    $78,375   $2,351     $12,508
     42500      922           5     2.000   $118,074   $102,527   $2,051     $14,559
     48000      923         4.7     0.300   $144,044   $131,059     $393     $14,952
     52500      924         3.7     1.000   $152,355   $148,200   $1,482     $16,434
     58000      925           2     1.700   $160,326   $156,340   $2,658     $19,092
     63000      926         1.6     0.400   $168,262   $164,294     $657     $19,749
     70500      927         1.4     0.200   $176,062   $172,162     $344     $20,093
     79500      928         1.2     0.200   $183,964   $180,013     $360     $20,453
     90000      929         0.9     0.300   $191,832   $187,898     $564     $21,017
    102000      930       0.65      0.250   $199,359   $195,596     $489     $21,506
    112000      931         0.5     0.150   $207,432   $203,396     $305     $21,811
    128000      932       0.38      0.120   $215,266   $211,349     $254     $22,064
    142000      933         0.3     0.080   $225,621   $220,443     $176     $22,241
    157000      934       0.22      0.080   $227,877   $226,749     $181     $22,422
Where do we begin in formulation?

                                             Detention pond?




                  Non-         Channel Modification?
                  Structural
High ground       Measures?
                                                 Town limits
behind red line
                                  Levee/Wall?
First or Last?

                          Detention pond




High ground
behind red line

                  Levee
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
Initial Formulation (we have only just begun)

  Measure        NED Cost    NED Benefit Net NED Benefit

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

  Pond                $40M         $20M         -$20M

  Levees/Walls        $60M         $80M         $20M

  Channel            $100M         $85M         -$15M
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?

                                  Levee alignment


              Reach 1
                                    Levee tie-back
                                    options
                   Reach 2

 High ground                                         Town limits
 behind red line        Reach 3
 Separable Increments of a Flood
 Damage Reduction Plan

                                NED       Net NED
 Plan Increment    NED Costs   Benefits   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?

                               NED       Net NED
 Plan Increment   NED Costs   Benefits   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

Where does the water go?
                            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
          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 Role
Prior to 1986:


                Not as politically active

                Uninvolved in project development

                No cost sharing other than LERRD’s
          Sponsors’ 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 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)
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
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
Demanding 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 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.

				
DOCUMENT INFO