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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.
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