HLTH 6200 Week 8 Flood Mitigation Options Menu Example

Mitigation Options for Mill River Flooding: A Menu of Six Measures, What Each Changes and Who Pays Versus Who Is Protected

Student Name

Walden University

HLTH 6200: Risk Assessment, Preparedness, and Disaster Mitigation

Instructor Name

Month Day, Year

Mitigation Options for Mill River Flooding: A Menu of Six Measures, What Each Changes and Who Pays Versus Who Is Protected

Purpose

This document lays out six measures that could reduce the county's riverine flood risk. It does not rank them; ranking waits for the benefit-cost brief and the priority memo. Instead, each measure is described in the same terms so that very different measures can be compared on one page: what it changes, likelihood of flooding or the losses when flooding occurs; which consequence categories it affects; who carries the cost; and who receives the protection. Federal guidance for local mitigation planning asks jurisdictions to identify and analyze a range of specific mitigation actions for each hazard (Federal Emergency Management Agency, 2023), and this menu is that analysis for flooding. The county and figures are a composite.

Measure 1: Voluntary Buyout of Repetitive-Loss Homes

What it changes: loss, by removing exposure. About 60 homes in the deepest part of the floodplain have flooded repeatedly. Buying them from willing owners, demolishing them and keeping the land as open space removes those homes from future floods entirely. Categories affected: property and life safety. Who pays: typically federal mitigation grants with a state and local share, plus the time and disruption borne by owners who move. Who is protected: the departing households, and taxpayers who would otherwise fund repeated repairs and response. A national study of buyouts found they have been more common in counties with higher incomes and populations, but that within those counties, bought-out properties tended to be in areas of greater social vulnerability (Mach et al., 2019). That pattern raises questions about whether participants are protected or pushed out, which a voluntary program must address through fair offers and relocation help.

Measure 2: Elevating Homes

What it changes: loss, by raising living space above expected flood levels while leaving the home in place. Categories affected: property, with some life safety benefit if residents can shelter above the water. Who pays: grants usually cover much of the cost, with homeowners paying a share and bearing months of disruption. Who is protected: the owners, who keep their homes and neighborhood. Elevation suits structurally sound homes in shallower flooding and leaves streets and access routes flooded.

Measure 3: Floodproofing the Wastewater Treatment Plant

What it changes: loss, by protecting the plant's electrical and pumping equipment with a perimeter wall and by raising critical equipment above the 0.2% annual chance flood level. Categories affected: continuity of services, primarily. Who pays: sewer ratepayers across the system, possibly with grant help. Who is protected: about 52,000 residents served by the plant, most of whom live outside the floodplain. This is the measure with the widest gap between where the hazard is and who benefits.

Measure 4: A Floodwall for the Downtown Riverfront

What it changes: likelihood, by preventing floods up to the wall's design level from reaching the area behind it. Categories affected: property and continuity downtown. Who pays: a large capital cost, usually with substantial local share and long-term maintenance. Who is protected: downtown businesses and the properties directly behind the wall. Researchers have long warned of the levee effect, in which structural protection encourages more development behind the barrier, so that losses are larger when a flood exceeds the design level or the structure fails (Tobin, 1995). A floodwall therefore reduces frequent losses while potentially increasing the rare, catastrophic one.

Measure 5: Higher Elevation Standards for New Construction

What it changes: future loss, by requiring new or substantially improved buildings in the floodplain to be built with their lowest floor at least two feet above the base flood elevation. Categories affected: property, over time. Who pays: builders and buyers of new or rebuilt structures, through higher construction costs. Who is protected: future occupants, lenders and the flood insurance system. It does nothing for existing homes.

Measure 6: Flood Warning and Nursing Home Evacuation Planning

What it changes: loss of life and injury, by improving warning lead time from the river gauge, closing flooded roads automatically and setting a written trigger and transport plan for evacuating the 96-bed nursing home. Categories affected: life safety. Who pays: the county and the nursing home, at relatively low cost. Who is protected: drivers who would otherwise enter floodwater and the nursing home's residents.

The Menu Side by Side

Table 1 summarizes the menu.

Table 1

Flood Mitigation Menu for the Mill River (Composite County)

What the Menu Shows Before Any Ranking

Even before ranking, the menu shows that the measures are not substitutes. They act on different consequence categories, protect different people and place costs on different groups. The measure protecting the most people, wastewater floodproofing, has its benefits far outside the floodplain. The measure with the most direct life safety effect, warning and evacuation planning, is the cheapest. And the measure most often proposed by downtown interests, the floodwall, carries the greatest risk of making a rare catastrophe worse. The benefit-cost brief will compare two of these measures in money terms; the priority memo will decide the order.

Some measures also combine well. Buyouts and higher elevation standards reinforce each other, since one removes the most exposed homes and the other keeps new exposure from replacing them. Warning and evacuation planning complements every structural measure by covering the floods those measures do not stop. A final plan is likely to include several measures, which is why describing them on the same terms matters more than choosing one.

References

Federal Emergency Management Agency. (2023). Local mitigation planning policy guide (FP 206-21-0002).

Mach, K. J., Kraan, C. M., Hino, M., Siders, A. R., Johnston, E. M., & Field, C. B. (2019). Managed retreat through voluntary buyouts of flood-prone properties. Science Advances, 5(10), Article eaax8995. https://doi.org/10.1126/sciadv.aax8995

Tobin, G. A. (1995). The levee love affair: A stormy relationship? Water Resources Bulletin, 31(3), 359-367. https://doi.org/10.1111/j.1752-1688.1995.tb04025.x