> **Time: 15 -- 20 minutes**

Larry Larson and Rod Emmer

SESSION 15. What are Hazards?

WHAT -- key concepts

1.  Authors define hazard, hazard event, hazard identification, and
    flood hazard in slightly different terms. But these definitions
    share related concepts. Identify and discuss some of the common
    ideas and concepts these terms share.

ANSWER:

a\. A hazard may be connected to human activity.

b\. Hazards are extreme events.

> c\. Hazards generally pose a risk of damage, loss, or harm to people
> and/or their property.

2.  Discuss the criteria for describing a "flood" as used by the
    National Flood Insurance Program when mapping a Special Flood Hazard
    Area as contrasted to a natural event.

> ANSWER:

FLOOD is a general and temporary condition of partial or complete
inundation of two or more acres of normally dry land area or of two or
more properties from overflow of inland or tidal waters, from unusual
and rapid accumulation or runoff of surface waters from any source, or
from mudflow (FEMA, 2001a). \[notice how FEMA placed conditions on its
definition, which omits smaller floods\]

SPECIAL FLOOD HAZARD AREA is an area of land that would be inundated by
a flood having a 1-percent chance of occurring in any given year (also
referred to as the base flood or 100-year flood) (FEMA, 2001a).

What the profession knew, but was seldom explained and even less seldom
understood was **probability theory.** First, our prediction might be
based on stream gage records of far less than 100 years, often 10 to 30
years, meaning there was a great chance the predicted event reflected a
period of abnormal flooding, and was not accurate. In addition, the
"once every 100 year average" would only balance out only over perhaps
thousands of years. As history has shown, the predicted 1% event can and
has occurred more than once in the same year; has occurred four times in
eight years on some major streams, etc. It is simply a predicted
probability.

SO WHAT -- Implications and impacts

1.  A flood hazard encompasses four elements that should influence which
    management practices should be employed. Identify and discuss each
    of these four elements.

> ANSWER:

1\. **severity**: magnitude (depth, velocity, quantity), duration (time
period), and extent (coverage, area, expanse);

2\. **probability or occurrence interval:** frequency (annual, 1%.
0.2%), seasonality, and probability of re-occurrence;

3\. **location or distribution across space**: geographic location,
spatial distribution, and presence on the landscape; and

> 4\. **countdown interval or speed of occurrence**: rapidity of
> commencement, warning time, and life cycle (flash flood, slow rise
> flooding, etc.).

NOW WHAT -- Management measures and tools

1.  Now that you know what constitutes a "flood hazard", how would you
    use this information to develop management measures and tools?

> ANSWER:
>
> Management measures and tools must include a range of options, such as
> physical modifications of the landscape and biological techniques to
> stabilize landforms and reduce runoff, erosion, and sedimentation.
> Regulatory and planning practices help people and businesses reduce or
> eliminate flood damages and help victims and communities recover after
> a flood and prepare for and mitigate damages from the inevitable next
> event.

SESSION 16 What is a Risk?

WHAT -- key concepts

> 1\. What is a Risk? What is Vulnerability?
>
> ANSWER:
>
> **RISK** - The estimated impact that a hazard would have on people,
> services, facilities, and structures in a community; the likelihood of
> a hazard event resulting in an adverse condition that causes injury or
> damage. Risk is often expressed in relative terms such as a high,
> moderate, or low likelihood of sustaining damage above a particular
> threshold due to a specific type of hazard event. It also can be
> expressed in terms of potential monetary losses associated with the
> intensity of the hazard (FEMA, 2001, p. a-6).
>
> Vulnerability is the level of exposure of human life and property to
> damage from natural hazards (Schwab et al. 1999a, p. 330).

SO WHAT -- Implications and impacts

> 1\. Define the relationship between Risk and Vulnerability. How is
> each of them shown or demonstrated?
>
> ANSWER:

**Risk** identifies the geographic areas most likely to be affected by a
given natural hazard, which in our case is the base flood.

1\. We usually show risk areas on a map. FEMA has done this for us on
the FIRM.

2\. People can live and work within a risk area and be less vulnerable
to the hazard. Some buildings within the defined SFHA do not flood
because they are flood proofed, elevated, or in some other way
protected. **(PP10, Two houses...)**

The people and the infrastructure that serves them are still
**vulnerable**.

1\. Getting to and from a structure, having power or water, etc. may
still present a major problem and cost.

2\. Many people and structures in the SFHA are vulnerable. These
properties will flood and suffer damages.

NOW WHAT -- Management measures and tools

> For determining what will be damaged, we divide the community into
> critical facilities, social enclaves, economic activities, and
> environmental components. Discuss how this information can be used to
> identify and prepare management measures and tools to reduce or
> eliminate flood damages.
>
> ANSWER:
>
> Risk states the probability of an event, in our case flooding.
> Vulnerability describes the susceptibility of a place to damage.
>
> Once we know where the risk exists and what is vulnerable we can
> estimate the direct and indirect (primary and secondary) adverse
> impacts resulting from flooding. This serves as the base for preparing
> a mitigation plan and implementing mitigation measures.

SESSION 17 Assessing Risk and Vulnerability to a Flood Hazard -- an
Exercise

WHAT -- key concepts

NO QUESTIONS ARE PROPOSED FOR SESSION 17 AS THIS IS AN EXERCISE.

SO WHAT -- Implications and impacts

NOW WHAT -- Management measures and tools

SESSION 18 A History of Floodplain Management

WHAT -- key concepts

1\. Floodplain management is defined by the interest of the
practitioner. Distinguish among floodplain management of the physical
landscape, biological components, and human activities?

> ANSWER:
>
> PHYSICAL LANDSCAPE: The physical landscape includes the channel,
> overflow deposits normally saturated and/or covered by water at least
> part of the year, and elevated features inundated on a less frequent
> but still predicable basis. Management practices are:
>
> channels - dredging, the placement of riprap and concrete mats,
> groins, and diversions;
>
> overflow deposits (point bars, swamps, and marshes) - construction of
> drainage systems, embankments and structures to direct water, and
> pumps; and
>
> elevated features (natural levees, terraces, and alluvial fans) -
> artificial levees and floodwalls, channels, canals, and ditches, and
> dams.
>
> BIOLOGICAL COMPONENTS: The biological landscape includes the channel,
> riparian zone, adjacent wetlands, and higher ground. Management
> practices are:
>
> physical - drainage, dredging, dams, and embankments;
>
> manipulation of the vegetation - cutting, clearing, silvaculture,
> agricultural practices, and use of herbicides; and
>
> introduction of exotic species.
>
> HUMAN ACTIVITIES: The third approach to floodplain management focuses
> on the structural and nonstructural measures that reduce flood
> damages.

SO WHAT -- Implications and impacts

> ANSWER:
>
> Sessions 3 - 14 discussed management of the physical landscape and
> biological components of areas subject to floods. Session 18 focuses
> on floodplain management of human activities.
>
> When human activities are considered we can lower or eliminate the
> adverse impacts of floods while protecting and maintaining the natural
> values and functions of floodplains.
>
> Three basic strategies are: (1) modifying the susceptibility to flood
> damage and disruption, (2) modifying the floods themselves, and (3)
> modifying (reducing) the adverse impacts of floods on the individual
> and the community (FEMA, 1986, p. IV-1).

NOW WHAT -- Management measures and tools

> ANSWER:
>
> We have established that we are working to maintain and protect the
> natural values and functions of floodplains while lowering or
> eliminating the adverse impacts of floods. Now we can select the
> appropriate management measures or tools for flood damage reduction.
> The palette of options includes:
>
> 1\. STRUCTURAL MEASURES represent the engineering approach.
>
> a\. Corrective Measures address existing problems.
>
> b\. Preventive Measures avoid creating new problems.
>
> c\. Examples of structural measures are:
>
> 1\'. Dams and reservoirs
>
> 2\'. Dikes, levees, and floodwalls
>
> 3\'. Channel alterations
>
> 4\'. High flow Diversions and spillways
>
> 5\'. Land treatment measures
>
> 2\. NONSTRUCTURAL MEASURES are the people approaches.
>
> a\. Corrective Measures address existing problems.
>
> b\. Preventive Measures avoid creating new problems.
>
> c\. Both measures may be address the susceptibility of people to
> flooding or modify the impacts of flooding.
>
> 1\'. SUSCEPTIBILITY:
>
> a\'. Acquisition and relocation
>
> b\'. Floodplain regulations and building codes
>
> c\'. Development and redevelopment policies
>
> d\'. Floodproofing and elevation in place
>
> e\'. Disaster preparedness and response plans
>
> f\'. Flood forecasting and warning systems
>
> 2\'. MODIFY THE IMPACTS OF FLOODING
>
> a\'. Information and education
>
> b\'. Flood insurance
>
> c\'. Tax Adjustments
>
> d\'. Flood emergency measures
>
> e\'. Disaster assistance
>
> f\'. Post-flood recovery
>
> g\'. Preservation and restoration strategies to manage natural and
> cultural resources of the floodplain

SESSION 19 Mitigating Flood Losses

WHAT -- key concepts

> Define and discuss mitigation as the most important element of
> floodplain management.
>
> ANSWER:
>
> Mitigation encompasses those actions taken to eliminate or reduce to
> an acceptable level the undesired consequences of floods.

SO WHAT -- Implications and impacts

> ANSWER:
>
> For the community and individual mitigation means preventing flood
> damages, protecting existing land uses and future development,
> reducing injuries, and avoiding loss of life. Mitigation measures
> include a range of structural and nonstructural practices that when
> implemented have positive (favorable) characteristics and negative
> (adverse) characteristics that should be considered by decision-makers
> when addressing flood damage reduction.

NOW WHAT -- Management measures and tools

> ANSWER:
>
> Mitigation measures include a range of structural and nonstructural
> practices as identified in Session 18.
>
> The instructor should ask the class to discuss the beneficial and
> adverse attributes of structural and nonstructural practices that
> occur in proximity to their educational institution. The following is
> an example of beneficial and adverse attributes of the National Flood
> Insurance Program.

Flood insurance (discussed in detail in Session 18)

1\. Functions

a\. A Federal program providing property owners in participating
community the opportunity to purchase flood insurance for structures and
contents

b\. Flood insurance is available through the National Flood Insurance
Program.

c\. To participate, the community must adopt and enforce floodplain
management measures applicable to the Special Flood Hazard Area. An
approved regulatory program is designed to reduce future flood damages.

2\. Beneficial Attributes

a\. Nationally, by 2005 20,000 communities with identified floodplains
participate in the National Flood Insurance Program.

b\. Administrative costs, mapping, and other NFIP expenses are paid
through insurance premiums and fees. This reduces the costs to the
taxpayer for disaster assistance.

c\. Insurance claims, unlike loans (principle plus interest), do not
have to be repaid.

d\. As of 2004 total building coverage available on a single-family
dwelling is \$250,000 plus contents (insurance coverage limits of
\$100,000) while grants are very small (sometimes only \$10,000).

e\. Similar to all insurance programs the NFIP spreads the cost of
insurance through time and over and across a large number of properties
that are at risk.

3\. Detrimental Attributes

a\. To be eligible for flood insurance a property owner must maintain
their flood insurance policy and pay the premiums.

b\. Communities must enforce floodplain regulations on how properties
within the Standard Flood Hazard Area may be used, constructed, or
reconstructed.

c\. The NFIP does not reduce damages. To gain lower premiums owners are
encouraged to reduce their exposure. The Community Rating System does
the same thing for communities.

SESSION 20 Mitigation Programs

Identify and discuss selected programs available for reducing or
eliminating flood damages. (INSTRUCTOR MAY CHOOSE TO FOCUS ON SPECIFIC
PROGARMS THAT HAVE A DIRECT APPLICATION TO THE LOCAL WATERSHED).

WHAT -- key concepts

> ANSWER:
>
> A range of federal, state, and local programs and activities are
> available to mitigate flood damages. Many federal programs offering
> technical assistance such as those by FEMA rely on bottom up efforts
> and provide technical or financial assistance to implement appropriate
> mitigation approaches. On the other hand, structural approaches by the
> Corps and NRCS are most often top down programs.

SO WHAT -- Implications and impacts

> ANSWER:
>
> Federal, state, and local assistance addresses many aspects of flood
> losses, including small business loans, rehabilitation, and planning.
> The mitigation programs contribute to making the community and the
> victims less susceptible to floods. Existing problems are corrected
> and the potential for flooding are integrated into future activities.

NOW WHAT -- Management measures and tools

> ANSWER:
>
> Instructor should select one or more programs and have students
> discuss the characteristics and application of the program(s) to
> issues important to their watershed or region. For example, the class
> may discuss the HMGP and show how it applies to their community.