Unit 3 FEMA Flood Moduleflghc.org/ppt/2014/Training Sessions/TS20 Benefit List... · 2016-02-29 ·...

Unit 3. Flood BCA Module 3-1

Unit 3

FEMA Flood Module


Unit 3 Objectives

Define a flood event and the different types of flood zones and flood mitigation projects

Describe the National Flood Insurance Program (NFIP) tenets

Identify the sources of documentation necessary to complete a successful Benefit-Cost Analysis (BCA)

Review the Flood portion of the BCA module

Identify available resources in the BCA Tool

Unit 3. Flood BCA Module

Flood depths = flood elevations minus FFE

First Floor Elevation (FFE)

Flood Elevations

(10-, 50-, 100-, 500- years)

Flood Damages

3-3

Flood Module Overview

Flood depths = flood elevations minus FFE

Unit 3. Flood BCA Module 3-4-4

Flood Statistics

Floods are the most common, most predictable, and most

costly of all natural disasters in the United States

90 percent of all presidential disaster declarations involve

flooding

Congress established the NFIP in 1968 to regulate affordable

flood insurance for communities in flood-prone areas

Through NFIP, FEMA has identified and mapped out more

than 21,000 communities


Obtaining Riverine Data

Unit 3. Flood BCA Module -63-6

Flood Terminology Review Activity

Match the terms and

their definitions.

When you think that

you have the correct

answers, let the

instructor know.


BCA Information Provided by a FIRM

A FIRM provides important BCA data inputs:

If the property is in the Special Flood Hazard Area (SFHA)

Flood zone

Base Flood Elevation (BFE) for the property

Community number, map panel and effective date


How to Read a Flood Insurance Rate Map (FIRM)


How to Read a FIRM

The FEMA FIRM Tutorial is a step-by-step process that you may

follow to obtain hazard-specific information on a FIRM. The tutorial

educates users on the use and application of FEMA FIRMs.

The full tutorial can be found at

http://www.fema.gov/media/fhm/firm/ot_firm.htm

This tutorial will help the user:

Find the correct FIRM panel

Find the general location of a property

Find the specific location of a property

Identify the flood insurance risk zone designation


How to Read a FIRM (continued)

Step 1: Find the

Correct Panel

Use the index to find

the FIRM panel you

need. This sample

index is composed of

four panels (0001,

0002, 0003, and 0004).

Determine the general

area of your property

and locate it on the

index. Check the title

boxes on the panels to

find the panel you need

– panel 0004 in this

example.



Step 2: Find the General

Location

After obtaining panel

0004, find the general

location by referring to

features such as major

roads or city limits.



Step 3: Find the Specific

Location of the Property

To find the specific location

and dimensions of the

property refer to:

A plat map,

A tax assessor’s map, or

The property description on the deed.

Then convert the known

property dimensions to inches

using the flood map scale and

measurements on the flood

map panel.



Step 4: Identify the Flood

Insurance Risk Zone of the

Property

As shown on the map on the

right, the property you are

considering buying is partially

within the dark-tinted SFHA.

Identify the flood insurance risk

zone designation for the

property by finding the labeled

zone.

The SFHA near the property is

labeled Zone AE.


Obtaining Data from a Flood Insurance Study (FIS)


BCA Information Provided by a Flood Insurance Study

A FIS provides important BCA data inputs:

Flood elevation data from flood profiles

Streambed elevation

Flood discharges


Obtaining Riverine Data

This section outlines a step-by-step process to obtain hazard-specific

information from a FIRM and a FIS that are needed to complete a

comprehensive BCA

The full FEMA tutorial can be found at

http://www.fema.gov/media/fhm/fis/ot_fis.htm

This tutorial will help the user:

Locate and effectively use a FIS flood profile

Understand and identify flood frequencies

Determine the BFE and Streambed Elevation of a riverine property

Locate flood discharge data


Flood Profiles

A flood profile is a graph of the flood elevations along the centerline of a stream. Flood profiles show the predicted water surface elevation for the 100-year-flood event (1-percent-annual chance), and often show the flood elevation profiles for the 10-, 50- and 500-year (equal to the 10-, 2-, and 0.2-percent annual chance, respectively) flood events.

Other information shown on the flood profiles include:

Location of flood map cross sections (a letter within a hexagon)

Location of streets crossing streams

Streambed elevation

Flood profiles should be used to determine the precise BFE for an area in the floodplain, rather than the FIRM, where the BFEs are rounded to the nearest whole foot. Precise streambed elevations can be derived using this same method.


Obtaining Riverine Base Flood Elevations (BFE)

Step 1: Locate the property ( ) on the Flood Insurance Rate Map and

identify the flooding source


Obtaining Riverine BFEs (continued)

Step 2: Locate the boundary of the property. Locate a physical feature

near the site that appears on the flood profile, such as a road or an

intersection.



Step 3: Using the map scale, measure the distance along the stream centerline on the FIRM from the reference location to the project site. Note that this distance is greater than the straight-line distance from

the reference location to the project site.



Step 4: Measure the distance from the reference location (e.g., road or

intersection) to the site on the profile.



Step 5: Draw a vertical line to find where the site intersects the flood

profiles.



Step 6: Draw a straight line to the edge of the graph to determine the

elevations for each of the 10-, 50-, 100-, and 500-year flood profiles

at the project site.


Obtaining Streambed Elevation

The streambed, or the bottom of a stream below the water source,

provides a baseline for riverine measurement.

The Streambed Elevation is easily located on the flood profile by the

symbol indicated below and can be determined using the same

method as you would the BFE.


Obtaining Flood Discharge Data

The Summary of Discharges Table lists the peak water discharges for

various flood frequencies at locations within the study area.

For example, using the summary of discharges table below, the 100-year

flood discharge for Cobb Brook at the confluence with the Rocky River is

1,080 cubic feet per second (cfs). This means that during the peak of the

100-year flood, 1,080 cubic feet of water will pass this point each second.


Peak Discharges for a Site

To determine the peak discharges for a specific site:

Locate the flooding source identified for the project site on the

Summary of Discharges table (within the community’s FIS).

Identify the closest physical location to the project site that is listed

for the flooding source.

Enter the peak discharges for the closest location to the site for the

10-, 50-, 100-, and 500-year floods into the BCA Tool.


Obtaining Coastal Data


Coastal Stillwater Elevation

Most coastal floods are caused by coastal storms, usually hurricanes and

northeasters. Such storms bring air pressure changes and strong winds

that pile water up against the shore in what is called a storm surge.

Based on data from past storms, computer models simulate coastal storms

to determine the Stillwater Elevation -- the elevation of coastal floods

without waves.

Stillwater Elevations are found in the Summary of Stillwater Elevations

table in a FIS, typically in Section 3.


As with riverine studies, a hydraulic analysis determines where moving water

goes. The coastal flood engineering survey uses techniques similar to those

used in a riverine study, but it uses transects instead of cross sections.

Transects


Wave Runup

In addition to storm surge, wave action is an important aspect of

coastal storms. Wind-driven waves produce water velocities and

impacts that may cause significant structural damage.

When waves hit the shore, water moves with such force that it

keeps traveling inland, called wave runup.

The official BFE of coastal areas is the Stillwater Elevation plus

wave runup, or the wave crest elevation, whichever is greater. The

resulting BFE can be many feet higher than the Stillwater Elevation.


Obstructions such as dunes or buildings break waves, dissipating the wave

energy so that wave height and BFEs are reduced as you go inland.

Coastal Obstructions


Coastal High Hazard Area

Coastal High Hazard

Areas are the most

hazardous part of the

coastal floodplain due

to their exposure to

wave effects. These

areas are designated

as V Zones where the

"V" stands for "velocity

wave action," and

includes an increased

degree of risk. Coastal

flood areas not within

the coastal high hazard

area are mapped as A

Zones.



Step 1: Locate the property and read the flood zone and BFE on a

FIRM. The BFE is listed in parentheses below the zone label. Unlike

Riverine properties, the BFE cannot be found in an FIS Flood Profile.

Property Location



Step 2: Locate the property on the Transect Location Map in the FIS.

A description of the start of the transects can be found on the

Transect Location Map.

Property Location



Step 3: Find the 100-year Stillwater Elevations at the start of the two

transects nearest the property in the Transect Data Table in the FIS.



Step 4: Interpolate between the two 100-year Stillwater Elevations at

the transects to estimate the 100-year Stillwater Elevation at the

property.

Transect 1 100-year Stillwater Elevation = 10.0 feet NGVD

Transect 2 100-year Stillwater Elevation = 10.0 feet NGVD

The property is halfway between Transect 1 and 2, so it would be

equal to the midpoint between these two transects, which is 10 ft.

NGVD.

Stillwater Elevation = 10 feet NGVD


Flood BCA Data Inputs and Documentation

3-37


Data Documentation Template

Reminder: the Flood Data Documentation Template gives you

potential data sources and can be used as a data checklist

3-38


Flood BCA Tool File Path

Mitigation Project Type

Mitigation Project Cost

Hazard-Specific Data

Structure Information

Depth Damage

Functions


Flood BCA Documentation: General Guidance

Data used in place of

FEMA standards or

default values MUST

be documented

Documentation should include

justification for the use of data in

place of FEMA values.

Hydrologic and hydraulic analyses

Building Replacement and Contents Values

Elevation Certificate(s)

All data must be obtained

from a credible source

Federal, State, county, regional, and local

government agencies

Qualified professionals such as licensed

architects, engineers, and surveyors





Mitigation Project Types

Acquisition

The purchase and demolition of a building. Future damage is eliminated because the project site is deed-restricted as open space.

Elevation

The raising of a building on an extended foundation or fill to place the lowest floor at or above the designated flood elevation.


Mitigation Project Types

Dry Flood Proofing/Flood Barrier

Mitigation measures added or

incorporated into an asset to

prevent flood damage by

making the exterior walls

impermeable to floodwater.

Drainage Improvement

An activity within or adjacent to

a flood source intended to

improve the flow capacity,

drainage, erosion and

sedimentation control, or

stability.







Unit II: Estimating Costs and Benefits

Pre-construction, Construction, Ancillary, and Annual Maintenance Costs

Sources:

Local historical cost data

Current contractor bids

Cost estimating software

Flood BCA Documentation: Mitigation Project Cost







FIS and/or Hydrology and Hydraulics (H&H) Study

Riverine: Flood Profile, Streambed Elevation, Discharges

Coastal: Stillwater Elevation (SWEL), BFE or 100-year elevation including wave action

FIRM

Panel Number, Effective Date, Community ID Number

Flood BCA Documentation: Hazard-Specific Data








Elevation Certificate

Flood BCA Documentation: Structure Information


SECTION B: FLOOD INSURANCE RATE MAP (FIRM) INFORMATION

B1: NFIP Community Name & Community Number

B2: County Name

B3: State

B4: Map/Panel Number

B5: Suffix


B6: FIRM Index Date

B7: Firm Panel Effective Date/Revised Date

B8: Flood Zone(s)

B9: BFE(s) (Zone AO, use base flood depth)


SECTION C: BUILDING ELEVATION INFORMATION (SURVEY REQUIRED)

a) Top of bottom floor (including basement, crawlspace, or enclosure floor

b) Top of the next higher floor

c) Bottom of the lowest horizontal structural member (V Zones only)



Other Sources of Structure Elevation Data

Professional Surveyor

Estimated elevation from a known

elevation of neighboring structure

Estimated elevation from high-

resolution topographic data (i.e.,

LiDAR)


Flood BCA Documentation:Structure Type and FFE

First Floor Elevation (FFE)

Finished Basement

Unfinished Basement

Finished Walkout Basement


Size of Building

Measured in square feet

Sources

Building Replacement Value

Cost per square foot to build a comparable structure

Sources



Foundation/Building Type, Number of Stories

What are some acceptable forms of documentation?

Where can you obtain them?

Flood BCA Documentation: Residential Structure


Primary Use of Building / Number of Stories

Sources: owner, local building inspector, local tax assessor’s office,

or title documents on letterhead from a credible source

Service Types by Facility (Value of Public Service)/Annual Budget

Service Name Examples: government, library, education, hospital,

emergency medical service (EMS), safe room, fire, police, or

Emergency Operations Center

Sources: agency providing service or published annual report

Flood BCA Documentation: Non-residential Structure







Depth Damage

Functions


Flood BCA Documentation: Depth Damage Functions

Depth Damage Functions

Choose from three options

Default

Library

Custom

If FEMA Standard Value is not used, sources include: historical loss records and engineering judgments





Depth Damage

Functions


Flood BCA Documentation: Depth Damage Functions

Adjusted Library

Depth Damage

Function for

Finished

Basements







Depth Damage

Functions

Other

Avoided

Damages


Flood BCA Documentation:Other Avoided Damages

BCA Tool automatically estimates avoided losses/damages:

Building and Contents Damages

Displacement Costs

Other Avoided Damages Table allows user-entered benefit

categories that may include:

Debris removal

Emergency Management Costs

Disruption of Life


Flood BCA Documentation: Contents Value

FEMA Standard Value: Contents

Residential and Default DDF (USACE) table:

100 percent of Building Replacement Value

(BRV)

All Others: 50 percent of BRV

If default is not used, sources include:

Insurance records

Appraisals

Receipts

Estimates based on current market prices for similar contents


Flood BCA Documentation: Displacement/Loss of Rent

Displacement/Loss of Rent

Monthly costs – Rent, furniture rental, utilities

one-time costs - moving and utility hook-up fees

FEMA Standard Values

$1.44 square foot per month for residential

Loss of Rent for rental properties only and do not include one-

time costs


What documentation is necessary

for the following benefits (damages

or losses avoided)?

Displacement Costs

Loss of Rent

Contents Value

Flood BCA Documentation: Documentation Exercise


BCA Tool Case Study

Flood

Case

Study 1


Overview of Flood BCA Tool

Add a new

structure

Select the

State and

county from

the drop-

down



Add a new

project

Organization

is

subapplicant

POC is the

person who

can answer

questions

about the

project



Associate the

structure with

the project.



Select Flood

to begin the

mitigation

project

analysis



Select

Mitigation

Project Type:

Acquisition

Elevation

Dry Flood

Proofing/

Flood Barrier

Drainage

Improvement

Other


Tool asks a series of questions to ensure the user has the appropriate documentation to conduct a full flood analysis

If documentation is deficient, Tool will redirect user to the Damage-Frequency Assessment module




Source of Flood Data?

FIS

H&H Study

Both

Project in a SFHA?

Located on FIRM

Source of Flooding?

Riverine

Coastal



Enter the

project useful

life

Select Yes to

detailed SOW

Enter project

Mitigation

Project Cost

Enter Annual

Project

Maintenance

Costs


Input

information

about flood

data source

using:

FIS

H&H Study

FIRM

Dynamic Help

will guide users

to location of

data



Riverine Data:

FFE and Diagram Description

Flood

Source

Name and

Flood

Profile

Number

Streambed

Elevation



Coastal Data:

FFE and Diagram Description

BFE or 100-

year elevation

including wave

action

Flood Source

Name and

Flood Profile

Number

Stillwater

Elevation




Total size of

building

(square feet)

BRV

(dollars

/square foot)

Demolition

damage

threshold



RESIDENTIAL

Riverine/Coastal A

Building Type

Foundation

Type

Basement

Coastal V

Obstruction



NON-RESIDENTIAL

Structure Type

Engineered

Pre-Engineered

Primary Use of

Building

Contents Value

Default changes

based on

primary use of

building

Displacement Cost

One-Time

Displacement Cost



Depth Damage Functions

Default/ Library/ Custom

Displacement Costs

FEMA Standard Value:

$1.44/sf/month

One-time

OR

Loss of Rent (rental property)

Building Contents Value

DDF Table populates after inputs are entered



Select other

benefits by adding

columns

Provide justification

Table is

dynamically

generated based

on user-entered

categories



Expected

Annual

Damages

Report

Provides annual damages based on earlier inputs

No further action

is required after

this screen



Summary of Benefits

provides a report on:

Annual Damages

(Before and After

Mitigation)

Expected Avoided

Damages

Mitigation Benefits

Mitigation Cost

Benefit-Cost Ratio


Flood BCA Case Study

Refer to the Case Study in the

Student Manual

Complete the Flood BCA module

using the Case Study


Review of BCA Activity

BCR Value Discussion

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Unit 3 FEMA Flood Moduleflghc.org/ppt/2014/Training Sessions/TS20 Benefit List... · 2016-02-29 ·...

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