Alternatives
Planning Objectives & Constraints
Based on Risk Signals, develop planning objectives for each planning reach. Planning objectives should be linked to the risks developed in the previous step and linked to the planning reach level of spatial organization.
- Each planning objective should consist of:
- Subject – The exposure extracted from the risk statement
- Effect – The effect we want to have on the risk
- Location – Linked to the planning reach
- Duration – Period of time (Typically base year + 50)
- Users should identify factors that will constrain the plan formulation
Measure/Alternative Development
Users should select from the standardized list of all measures deemed reasonable for managing the risk within each planning reach. Table 15 provides a comprehensive (though not exhaustive) list of CSRM measures by category, management approach, and management method.
In the context of the scoping tool, measures could be considered individual actions undertaken to address a portion or component of the risk. Alternatives are one or more measures sited at a location for the purpose of addressing one or more planning objectives. The ultimate goal of the scoping process is to develop a final array of alternatives, and understand the impact of the alternatives on the study scope.
Table 15. CSRM Measures by Category, Management Approach, and Management Method
Measure Category | Coastal Storm Risk Management Approach | Coastal Storm Risk Management Method | Measure List |
Structural | Coastal System Response Based | Armoring | Seawall |
Revetment | |||
Bulkhead | |||
Floodwalls | |||
Deployable Floodwalls | |||
Levees / Dikes | |||
Surge Barrier | |||
Ring-walls | |||
Armoring/Retrofit* | Road Elevation | ||
Restoration | Beach Nourishment | ||
Nearshore Nourishment | |||
Stabilization | Groins | ||
Breakwaters | |||
Natural & Nature Based Features | Restoration | Barrier Island | |
Tidal Flats | |||
Wetland | |||
Maritime Forest | |||
Wet Pine Savannah | |||
Mangroves | |||
Stabilization | Living Shoreline Vegetation | ||
Sub Aquatic Vegetation (SAV) | |||
Coral Reef Breakwater | |||
Oyster Reef Breakwater | |||
Living Shoreline Reefs | |||
Living Shoreline Sills | |||
Non-structural Measures | Exposure-Based | Permanent Retreat | Buyout & Acquisition |
Relocation | |||
Temporary Retreat | Flood Warning Systems | ||
Flood Emergency Preparedness Plans | |||
Evacuation Plans | |||
Vulnerability-Based | Retrofit | Building Elevation | |
Dry Flood Proofing | |||
Wet Flood Proofing | |||
Decision-Based | Informational | Floodplain Mapping | |
Risk Communication | |||
Risk Analysis | |||
Future Exposure | Flood Insurance | ||
Land Use Regulations | |||
Zoning | |||
Land Conservation |
Measure Cost
Upon selecting the range of measures to be used in the scoping process, users have the option of estimating a range of costs associated with those measures if they choose. Upon populating the relevant cost data for each measure the SCT should calculate and display annualized and constant dollar cost ranges. SCT items to consider include the following:
- Discount Rate
- Mob/ Demob/ Fixed Cost Range
- Unit Cost (Variable Cost Range)
- Unit Cost Parameter (Defined for each Parameter)
- # of Construction Events (Min, Max)
Measure Category | Measure Code | Measure Group Name | Measure Unit |
Structural | S-1 | Groins | $/LF |
S-2 | Seawall | $/LF | |
S-3 | Revetment | $/LF | |
S-4 | Bulkhead | $/LF | |
S-5 | Breakwaters | $/LF | |
S-6 | Floodwalls | $/LF | |
S-7 | Deployable Floodwalls | $/LF | |
S-8 | Levees / Dikes | $/LF | |
S-9 | Surge Barrier | $/LF | |
S-101F[2] | Beach Nourishment | $/LF | |
S-112F[3] | Nearshore Nourishment | $/LF | |
S-12 | Road Elevation | $/LF | |
S-13 | Ringwalls | $/LF | |
NNBF | NNBF-1 | Barrier Island | $/AC |
NNBF-2 | Tidal Flats | $/SF | |
NNBF-3 | Wetland | $/AC | |
NNBF-4 | Maritime Forest | $/AC | |
NNBF-5 | Wet Pine Savannah | $/AC | |
NNBF-6 | Mangroves | $/LF | |
NNBF-7 | Living Shoreline Vegetation | $/LF | |
NNBF-8 | Sub Aquatic Vegetation (SAV) | $/AC | |
NNBF-9 | Coral Reef Breakwater | $/LF | |
NNBF-10 | Oyster Reef Breakwater | $/LF | |
NNBF-11 | Living Shoreline Reefs | $/LF | |
NNBF-12 | Living Shoreline Sills | $/LF | |
Non-Structural | NS-1 | Buyout & Acquisition | $/Asset |
NS-2 | Building Elevation | $/Asset | |
NS-3 | Dry Flood Proofing | $/Asset | |
NS-4 | Wet Flood Proofing | $/Asset | |
NS-5 | Relocation | $/Asset | |
NS-6 | Flood Warning Systems | No Cost Included | |
NS-7 | Flood Insurance | No Cost Included | |
NS-8 | Floodplain Mapping | No Cost Included | |
NS-9 | Flood Emergency Preparedness Plans | No Cost Included | |
NS-10 | Land Use Regulations | No Cost Included | |
NS-11 | Zoning | No Cost Included | |
NS-12 | Evacuation Plans | No Cost Included | |
NS-13 | Risk Communication | No Cost Included | |
NS-14 | Risk Analysis | $/Study* | |
NS-15 | Land Conservation | No Cost Included |
- Unit cost range
- Unit cost parameter
Measure/ Alternative Affordability Analysis
The purpose of this analysis is to compare the range of costs to the range of damages. For instances where the estimated costs exceed the estimated economic benefits NED plans will be difficult to justify and overall project justification will likely require policy exceptions. If estimated costs are (roughly) equal to benefits for a given alternative NED justification will require complete prevention of damages.
- EAD – Annualized Test
- Consequences with Cost
Array of Alternatives
The final array of alternatives includes the combination of measures that the PDT will carry into detailed risk analyses following the Alternatives Milestone Meeting. The risk analyses are performed across the period of federal participation capturing lifecycle costs of measures, nonstationarity of hazards and exposure elements, and the resulting damages from coastal storm events and other damage drivers (as applicable).