Model 630 Dam Safety

National Flood Insurance Program
Community Rating System

CRS Credit for Dam Safety

2006

A community interested in more information on obtaining flood insurance premium credits
through the Community Rating System (CRS) should have the CRS Application. This and other
publications on the CRS are available at no cost from
Flood Publications

NFIP/CRS

P.O. Box 501016

Indianapolis, IN 46250-1016

(317) 848-2898

Fax: (317) 848-3578

[email protected]

They can also be viewed and downloaded from FEMA’s CRS website,
http://training.fema.gov/EMIWeb/CRS/index.htm

Contents

Section
Page
Introduction ......................................................................................................... 1

Objective....................................................................................................... 1
The CRS........................................................................................................ 2

630 Dam Safety .................................................................................................. 3

Elements Recognized in Activity 630 ........................................................ 3

Definitions .................................................................................................... 3
Security ......................................................................................................... 4

631 Credit Points ................................................................................................ 5

State Dam Safety Program (SDS) ............................................................... 5

Dam Failure Emergency Response Plan (DFP) .......................................... 7

632 Impact Adjustment ..................................................................................... 14

633 Credit Calculation ...................................................................................... 17

634 Credit Documentation ................................................................................ 18

State Dam Safety Program.......................................................................... 18

Dam Failure Emergency Response Plan..................................................... 18

635 For More Information ................................................................................ 19

Appendix A. Elements of an Emergency Action Plan .................................... A-1

Appendix B. An Example of CRS Credit for a Local

Dam Failure Emergency Plan ................................................... B-1

Credit for Dam Safety

−i−

Edition: 2006

[This page intentionally blank.]

Credit for Dam Safety

− ii −

Edition: 2006

Introduction
Objective
One of the objectives of the Community Rating System (CRS) is to protect lives and
health. CRS credit is provided for both state and local dam safety programs.
Dam failures have resulted in numerous disasters in the United States and around the
world. Although catastrophic dam failures are rare in the United States, the threat is
real, and communities should be aware
of the potential for a dam failure that
would affect their residents, and
Recent Disastrous U.S. Dam Failures
prepare for such a disaster.
Dams can create a false sense of
security for floodplain residents. Unlike
levees, they do not need flood
conditions to fail. They can be
breached with little or no warning and
send a wall of water downstream. The
combination of high velocity, great
depth, and short notice has proven
particularly deadly and destructive.
One way to minimize this hazard is to
enforce construction and maintenance
standards. This is usually done through
a state dam safety program.

• Toccoa Falls, Georgia—On

November 5, 1977, the Kelly Barnes

Dam failed, killing 39 students and

college staff and causing about $2.5

million in damage.

• Teton, Idaho—The Teton Dam failed
on June 5, 1976, killing 11 people
and causing property damage totaling
$400 million.
• Buffalo Creek, West Virginia—The
Buffalo Creek Dam failed on February
26, 1972, killing 125 people.

Although the legal definition of a “dam” for regulatory purposes varies from state to
state, many dams are very small. A dam may be as low as 5 feet, with an impoundment
of no more than 5 acre-feet of water. In many states, highway and railroad
embankments may legally be dams, although they may not be rigorously regulated.
Thus, if a community has one or more high hazard dams upstream, it should not
necessarily expect a 100-foot wall of water to suddenly swamp developed areas. On the
other hand, if a dam failure caused even a 25- or 50-year flood with no warning or
preparation on a clear day, the results still could be devastating.
In the last 20 years, federal and state agencies have made great strides in inventorying,
inspecting, and repairing unsafe dams. There are approximately 75,000 U.S. dams
listed on the National Inventory of Dams. These dams are over 25 feet high or have
over 50 acre-feet in storage, or they are smaller structures that pose a safety hazard to a
downstream population.
There are almost 11,000 dams in the United States that are classified as “high hazard”
dams. A high hazard dam is one whose failure threatens life and property. Of these
11,000 high hazard dams, fewer than 45% have emergency action plans (EAPs). All

Credit for Dam Safety

− 1 −

Edition: 2006

states require EAPs for new
dams, but only a few have
statutes that require owners of
existing dams to produce
EAPs.
Data from a dam’s EAP are
needed by downstream
communities to prepare for
their own emergency response
activities.

View northwest toward the breach in Teton Dam (Idaho)
during the dam’s failure. The canyon floor is flooded from
bank to bank, and all works there are completely inundated.
Photo by Mrs. Eunice Olson (Sylvester, 2006).

Even though most communities
are downstream from one or
more hazardous dams, few
have an emergency response
plan that adequately addresses
dam failure emergencies.

The objectives of this activity are
• To encourage state dam safety officials to complete their inventories of dams;
• To encourage state dam safety officials to get the most dangerous dams repaired or
modified to reduce the threat of dam failure;
• To encourage state dam safety officials to get EAPs completed for all dams that
pose high or significant hazards to downstream residents; and
• To encourage communities to integrate dam failure planning into their emergency
plans.

The CRS
The Community Rating System (CRS) is a part of the National Flood Insurance
Program (NFIP). When communities go beyond the NFIP’s minimum standards for
floodplain management, the CRS can provide discounts up to 45% off flood insurance
premiums.
Communities apply for a CRS classification and are given credit points that reflect the
impact of their activities on reducing flood losses, insurance rating, and promoting the
awareness of flood insurance. The Insurance Services Office’s ISO/CRS Specialist
reviews the community’s program and verifies the CRS credit. This includes a review
of the written procedures and records of an activity and, in some cases, a visit to sites
in the field.
A community applies using the CRS Application. CRS credit criteria, scoring, and
documentation requirements are explained in the Coordinator’s Manual. Copies of both
are available free from the office listed on the inside front cover of this publication.

Credit for Dam Safety

− 2 −

Edition: 2006

630 Dam Safety
The CRS credit for state dam safety programs and community dam failure planning is
provided under Activity 630 (Dam Safety) in the Coordinator’s Manual. This
publication explains the CRS credit criteria and gives examples.

Elements Recognized in Activity 630
This activity recognizes two approaches to improving dam safety:
• A state dam safety program provides a state-wide basis for developing an
inventory of dams, determining the risk downstream from dams, and monitoring
the condition of dams throughout the state. Except for dams they own,
communities generally have limited authority over dams that affect them,
especially if they lie outside the community. The acronym used in credit
calculation formulae, “SDS,” is a shorthand way to refer to the CRS credit. The
credit criteria are explained in Section 631.a of the Coordinator’s Manual.
• With detailed information on how upstream dams might fail, and based on regular
communications with upstream dam owners, communities should incorporate a
dam failure emergency response plan in their overall emergency response plans.
“DFP” is a shorthand way to refer to the CRS credit. The credit criteria are
explained in Section 631.b of the Coordinator’s Manual.
This publication reviews these elements and explains the requirements for verification
of credit by the CRS.

Definitions
Some terms and acronyms are used in this publication that may not be familiar to CRS
Coordinators.
Association of State Dam Safety Officials (ASDSO)—The Association of State Dam
Safety Officials (ASDSO) is a not-for-profit organization formed in 1984 in response to
several major dam failures across the United States during the previous decade. It was
recognized at the time that there was a great need for stronger regulatory programs.
ASDSO was established to encourage and assist states in setting up or upgrading their
dam safety programs.
Dam failure inundation area map—A map that shows areas subject to inundation after a
dam failure. These maps are similar to a floodplain map. They are usually part of an
emergency action plan (EAP) prepared by a dam owner. They may extend a long distance
downstream and affect a number of communities.
Emergency action plan (EAP)—A plan developed for a specific dam, usually prepared
by the dam owner, which specifies actions to be taken by the dam owner or operator in the
event of an impending or actual dam failure.

Credit for Dam Safety

− 3 −

Edition: 2006

Emergency response plan—For purposes of this document, an emergency response plan
is a plan developed by a community, a group of communities, or a county that defines the
local responsibilities in dealing with an emergency. This plan probably includes different
types of natural and human-caused emergencies, such as floods, tornados, hurricanes,
hazardous chemical spills, terrorist acts, etc. For CRS credit under this activity, it must
also include a response plan for failure of an upstream dam. Locally, it may be titled an
“Emergency Plan,” an “Emergency Preparedness Plan,” or other similar names.
National Inventory of Dams (NID)—The Water Resources Development Act of 1986
(P.L. 99-662) authorized the U.S. Army Corps of Engineers to maintain and periodically
update the National Inventory of Dams, and appropriated funds for that purpose. Section
215 of the Water Resources Development Act of 1996 (P.L. 104-303) re-authorized
periodic update of the National Inventory of Dams. For the 1998 update and beyond, the
Corps of Engineers has the lead responsibility, and is working with the Association of
State Dam Safety Officials, the Federal Emergency Management Agency (FEMA), and
other state and federal agencies. As of early 2001, the national inventory had 75,000
entries.

Security
The threat of terrorist activity in recent years presents a very real problem to dam
owners and operators and to local emergency management officials. Dam owners may
be reluctant to provide detailed information about their dams to others, and community
emergency managers may be constrained in how they use and disseminate dam failure
information.
These problems are very real, and the CRS makes no recommendations on how they
should be approached. To prepare its response to a dam failure emergency, a
community must have the kind of information contained in EAPs prepared by dam
owners. In order for the public to be prepared to respond to a dam failure in accord
with the community’s dam failure emergency response plan, some amount of
information on the effects of a dam failure must be made public. The CRS leaves it to
the community to determine the best way to provide the documentation required for
CRS credit while keeping vital information about the dams secure.

Credit for Dam Safety

−4−

Edition: 2006

631 Credit Points
This section discusses the two elements (state dam safety program and the community’s
dam failure emergency response plan) and the corresponding CRS credit points under
Activity 630. As in the Coordinator’s Manual, the credit criteria of the CRS Schedule
are shown in shaded boxes with double line borders. Scoring examples are shown in this
typeface.

This section also covers how the elements are scored, provides example language, and
identifies some of the more common problems and misunderstandings found in
community CRS applications.

a. State Dam Safety Program (SDS)
State dam safety programs are scored according to a separate Schedule for State Dam Safety
Programs, based on the standards outlined in the Model State Dam Safety Program developed
by the Association of State Dam Safety Officials and published by FEMA as Publication 123.
If the status of a state’s dam safety program is unknown, the community should contact the
FEMA Regional Office (see Appendix A of the Coordinator’s Manual) or the ISO/CRS
Specialist for that state (see Appendix G of the Coordinator’s Manual). If a state program
receives few or no points, it is hoped that local interest will encourage the appropriate state
agency or legislature to improve the state program.
This credit is available to all communities in states with credited dam safety programs,
including communities that are not downstream from any dams. However, if a
community owns or regulates the construction, operation, or maintenance of any dams,
the community dam safety program must meet the state standards for dam safety in
order for the community to be eligible for SDS credit. The separate dam safety
schedule requires states to advise FEMA when any community is in violation of the
state’s program.
Scoring
a. Two conditions are prerequisites for credit under this element:
1. If a state does not receive credit for this element, no community within
that state is eligible for credit for this element.
2. A community must meet state dam safety standards to receive credit for
this element.
SDS = up to 75 points, if the community is in a state with a dam safety
program that has been accepted by FEMA for CRS credit. The state dam
safety office must have stated that the community’s program is in compliance
with the state program.

Credit for Dam Safety

− 5 −

Edition: 2006

A CRS community does not have to do anything to receive SDS credit. Each year, state
dam safety officials complete a questionnaire and send it to FEMA for evaluation.
FEMA assigns the SDS credit for states that qualify. Each state also provides a list of
communities that are not compliant with its dam safety requirements.
The 2002 SDS credit for each state is shown below. This credit usually does not change
much from year to year, but the most current state credit can be obtained from the
FEMA Regional Office. A list of communities that are not compliant with their state
dam safety programs is also available from the FEMA Regional Office.
CRS Credit for State Dam Safety Programs
subject to revision

State
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Florida
Georgia
Hawaii
Idaho
Illinois
Kansas
Kentucky
Louisiana
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Montana

Credit
58
72
75
74
75
56
67
64
68
71
59
64
69
74
75
52
57
61
68
72

State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Pennsylvania
South Carolina
South Dakota
Texas
Utah
Virginia
Washington
Wisconsin
Wyoming

Credit
68
60
75
67
57
56
58
68
63
56
75
57
71
55
68
75
63
68
54

If its state has not earned SDS credit, a community could use whatever influence it has with the
state legislature to get the state dam safety program up to the minimum CRS standards for SDS
credit. If there is a state association of floodplain or emergency managers, it may be able to help.
NOTE: A community that received credit for Activity 630 in a previous application
does not need to submit a modification to revise or update its SDS credit. Its credit will
be revised automatically by the ISO/CRS Specialist to reflect its state’s credit.
Documentation Needed for Verification
All documentation for this element is provided to FEMA by the state dam safety official.
Credit for Dam Safety

−6−

Edition: 2006

b. Dam Failure Emergency Response Plan (DFP)
Emergency preparedness planning and emergency response take place at the community
level. In many locations, a county agency is responsible for emergency management
throughout the county, including the incorporated communities. In other locations, each
municipality is responsible for its own emergency planning and response.
Local emergency managers prepare for many natural and human-caused emergencies, from
floods, tornados, and earthquakes to hazardous materials spills, nuclear accidents, and
airplane crashes. They usually have a general plan that applies to all types of emergencies and
more specific plans for specific emergencies. To a specific emergency, the local emergency
manager must have specific information.
The first thing for the community to do is determine if there are dams upstream that
would adversely affect the community if they failed. On large rivers, such dams may be
a long ways upstream, outside the county the community is in, or even outside the
state. For most communities, the place to begin is with the state dam safety office.
Other sources of information are regional offices of the Corps of Engineers and the
U.S. Geological Survey.
If there is a dam that would cause flooding in the community, the next step is to obtain
the dam’s EAP, if one exists. Much of the information needed by the local emergency
manager must come from an EAP prepared for the dam.
EAPs are usually prepared by dam owners so that they and downstream communities
can understand the potential results of a dam failure and be prepared for them. A good
EAP will discuss the different ways that the dam may fail and the floods that will result
if such failures occur. An EAP that allows a community to qualify for DFP credit must
also include a hydraulic analysis that produces a dam failure inundation map, flood
elevations, and arrival times at various points downstream from the dam.
If there is no EAP for the dam, it is unlikely that the community will be able to receive
DFP credit for that stream reach. The state dam safety office may be able to require an
EAP from the owner, the community may produce an EAP for the dam, or the
community may be able to convince the dam owner that he or she should produce an
EAP in order to be a good neighbor. However, an EAP is a major technical
undertaking.
Some states require that dam owners prepare EAPs. California’s statutes include the
following requirements for maps of dam failure inundation areas:
8589.5. (a) Inundation maps showing the areas of potential flooding in the
event of sudden or total failure of any dam, the partial or total failure of
which the Office of Emergency Services determines, after consultation
with the Department of Water Resources, would result in death or personal
injury, shall be prepared and submitted as provided in this subdivision
within six months after the effective date of this section, unless the time
for submission of those maps is extended for reasonable cause by the
Office of Emergency Services.
Credit for Dam Safety

−7−

Edition: 2006

The local governmental organization, utility, or other owner of any dam so
designated shall submit to the Office of Emergency Services one map that
shall delineate potential flood zones that could result in the event of dam
failure when the reservoir is at full capacity, or if the local governmental
organization, utility, or other owner of any dam shall determine it to be
desirable, he or she shall submit three maps that shall delineate potential
flood zones that could result in the event of dam failure when the reservoir is
at full capacity, at median-storage level, and at normally low-storage level.

A dam failure emergency is possible whether there are structural problems with a dam
or not. As noted in the Washington State Department of Ecology Dam Safety Section’s
Example EAP, the following situations may cause a sudden release of water
downstream from a dam: earthquake; flood water entering the dam reservoir; erosion,
slumping/sloughing or cracking of the dam abutment; springs, seeps, bogs, sandboils,
increased leakage, or sinkholes; and landslides that affect dam operations.
An emergency plan adopted by a community usually gives the emergency manager
special authority to deal with emergencies. For example, he or she may use vehicles
and personnel from all community departments as needed. A good emergency response
plan tries to anticipate what materials and personnel will be needed for each type of
emergency. Section 610 of the Coordinator’s Manual has more information about
emergency response plans. Also, see CRS Credit for Flood Warning Programs, which
is available from the address on the inside front cover of this publication.
Scoring
b. Dam failure emergency response plan (DFP) (Maximum credit: 100 points)
DFP = DFP1 + DFP2 + DFP3
1. DFP1 = 25, if the community has the following:
(a) An emergency response plan that
(1) Specifies that the community will be notified of an impending or
actual failure of a dam upstream from the community;
(2) Provides projected inundation areas, flood elevations, and
estimated arrival times for flood peaks arising from a failure of the
dam; and
(3) Calls for an exercise at least annually. The results of the exercise
are evaluated and used to revise the response plan;
(b) A procedure to obtain annual reports by the dam operators on the
safety and operational status of their dams. Copies of these reports
must be sent to the community and the state dam safety office; and
(c) Monthly communication checks
emergency services officials.

Credit for Dam Safety

−8−

between

dam

operators

and

Edition: 2006

(a) Emergency Plans: Many communities have prepared multi-hazard emergency
response plans or comprehensive emergency management plans. Unless such a plan
has an annex, standard operating procedures, or other parts that specifically address
the community’s dam safety problem, it may not be specific enough to qualify for
CRS credit. For CRS credit, a dam failure EAP must specifically relate to the dam
safety issue and identify appropriate response activities.
An emergency response plan is adopted by the governing body of the community.
These plans generally reassign authority over community agencies during a declared
emergency. For example, in an emergency, the director of emergency management
may have authority over vehicles and other equipment normally assigned to public
works. Community staff from any department in the community may be temporarily
assigned to respond to the emergency. The dam failure emergency plan must be part of
this adopted plan.
In most states, most emergency management planning is done at the county level,
with specific community plans subordinate to the county plan. This recognizes the
fact that many types of disasters are widespread in area, and may affect several
communities at once. In these cases, the dam safety emergency plan may be partly
contained in the county emergency preparedness plan, and partly within the city’s
emergency preparedness plan. For example, the county may have the ability to
receive dam failure warnings on a 24-hour basis, while the city does not. In that case,
the county would activate its countywide emergency response plan and notify
affected communities. Each community would then activate its plan. The San Diego
County Emergency Plan states
In the early 1960s, all the cities and the County got together and formed a Joint
Powers Agreement which established the United San Diego County Emergency Services Organization (USDCESO) and the Unified Disaster Council
which is the policy making group of the Organization. It also created the Office
of Disaster Preparedness, which is staff to the Unified Organization . . .
This document was created by representatives of all of the jurisdictions in the
Operational Area and all of the agencies with any responsibilities in the plan. It is
intended to be adopted by all of the jurisdictions in the Operational Area with
minor modifications. The goal is to have emergency plans which are as similar as
possible throughout the Operational Area. That way if any one of the members
needs assistance from any of the other jurisdictions, everyone will be familiar with
the Emergency Plan. With representation from all agencies and jurisdictions, it
assures that the commitments that have been made in the plan are realistic.

The basis for a community’s dam failure response planning is the kind of
information contained in the EAP(s) for an upstream dam(s). A community can
develop the dam failure inundation maps and estimated arrival times of peak flows
and conduct exercises of its plan, but the dam owner or operator must agree to
notify the community in the event of an emergency that may lead to a dam failure.

Credit for Dam Safety

− 9 −

Edition: 2006

The dam owner or operator must also cooperate with the community to provide the
annual reports and monthly communications checks required for DFP credit. The
best way to ensure this cooperation is to have it included in the EAP(s).
(b) Annual Report: The annual report by the dam operators must include any factors that
have changed since the EAP was written that affect the safety of the dam or increase the
likelihood of its failure. Such factors might include the results of recent inspections,
revisions to the hydrologic studies used to forecast possible dam failures, revisions in the
operation plans, and/or current conditions such as the water level of the reservoir and the
snowpack in the watershed above the dam.
If an upstream dam owner is reluctant to prepare the annual report required for DFP
credit, the community should use any means necessary to obtain the information. If
a dam fails and the community is not prepared, there will be unnecessary suffering,
loss of property, and perhaps loss of life. Communities should work with their state
dam safety office and legislature to get such reports required from all dam owners.
(c) Monthly Communications Checks: Monthly communications checks with the
dam ensure that the dam owner or operator knows who to contact in the event of an
emergency. It may be decades between the time an EAP is prepared and the
occurrence of an emergency, and for most dams, a dam failure emergency will
never occur. However, the dam owner or operator and the community must be
prepared for an emergency every minute of every day.
If communication with the dam is made by telephone, the community’s emergency
plan should require a telephone call by emergency management staff to the dam
every month. If the dam is so remote that communication requires radio or satellite
communication, that system should be tested monthly.

2. DFP2 = 25, if the community has the following:
(a) credit for DFP1, and
(b) an adopted emergency plan that details at least three methods of
notifying affected residents of an imminent flood event resulting from a
possible or ongoing dam failure. At least three of the following
notification methods must be available:
•

Sound or voice siren system;

•

Telephonic notification, AM transmitters, and receivers dedicated
to dam failure notification;

•

NOAA Weather Radio. Receivers with Specific Area Message
Encoding (SAME) are preferred;

•

Mobile public address;

Credit for Dam Safety

− 10 −

Edition: 2006

•

Emergency Alert System;

•

Cable television override; and

•

Door-to-door notification.

Because a dam failure is generally unexpected, and because the flood wave resulting
from many dam failures travels downstream rapidly, the warning dissemination
methods appropriate for this hazard are those used in flash flood situations. In many
cases, there will be only a few hours to evacuate, and in some cases, only minutes.
Credit for DFP1 ensures that the community can be notified of an upstream dam failure
and that it has some idea how bad the emergency will be. DFP2 credit is provided if the
community is prepared to notify those residents who will be directly affected by a dam
failure.
Large institutions may need their own information dissemination plans. The following
is from a university’s emergency response plan:
ABC University recognizes its responsibility to provide accurate and timely
information to the campus community and the public during emergencies.
The University also recognizes its responsibility to students, faculty and staff
to respond to concerns about personal safety and security, and to follow
University policies concerning the release of personal information. During
emergencies, information will be provided to the campus community through
a variety of methods, including announcements in the news media, e-mail
and audix announcements, web pages, emergency hotlines, telephone trees,
and meetings in affected buildings and residence halls.

3. DFP3 = 50, if the community:
(a) Has credit for DFP1 and DFP2;
(b) Has an adopted emergency plan that includes evacuation routes and
detailed procedures for notifying and evacuating critical facilities,
specifically including schools, hospitals, nursing homes, jails, and
other locations where there are populations that may have difficulty
evacuating the dam failure inundation area; and
(c) At least annually notifies occupants in the dam failure area of the
hazard, the area affected, evacuation routes, and flood safety topics
appropriate to the hazard.

Credit for Dam Safety

− 11 −

Edition: 2006

Because dam failures are rare events, it will be difficult for people to believe that they
are in danger. It is necessary for them to receive repeated messages so that if the event
occurs they understand that they have to act quickly. When the time comes, they also
have to know what to do and where to go. Depending on the community’s situation,
they may have to put the family in the car and leave immediately, leaving animals to
fend for themselves and leaving all of their possessions.
Facilities with special populations are a particular concern in this type of emergency. It is
likely that the staff of such facilities do not have the ability to evacuate their students,
patients, clients, inmates, etc., and will need extraordinary assistance to avoid a catastrophe.
They should have an emergency plan, and they should exercise it regularly. The community
emergency manager should work with the management of such facilities to ensure that these
emergency plans address the potential hazards and meet the needs of their populations.
DFP3 gets into more detailed planning. Because dam failures are unusual events, people need
to have information readily available in order to know how to respond to a warning. A
nursing home may not have any idea how to move its residents if the community tells them
that there has been a dam failure upstream and they need to evacuate within six hours. Just
like the community, the nursing home needs an emergency response plan. The management
needs to know how long it will take to evacuate the clients, how many vehicles they will
need, where they will get them, etc.
Families and others also need to know what to do if notified of a dam failure. More information
on flood safety topics can be found in Activities 330 and 610 in the Coordinator’s Manual.
Documentation Needed for Verification
The community must provide the following documentation:
a. [Required only if the community is applying for credit under Section 631.b.1]
The portions of the community’s emergency plan or other documentation that
show the dam failure inundation areas, flood elevations, and estimated arrival
times, an annual report from the dam operator, annual exercises, and
monthly communications checks.

The community must provide a copy of the cover or other page that shows the date the plan
was adopted. It should also show the date the plan was last reviewed and/or revised. The
appropriate sections of the plan should be marked with the acronym “DFP1.”

b. [Required only if the community is applying for credit under Section 631.b.2]
The portions of the community’s emergency plan that detail at least three
methods of disseminating a dam failure warning.

The appropriate sections of the plan should be marked with the acronym “DFP2.”

Credit for Dam Safety

− 12 −

Edition: 2006

c. [Required only if the community is applying for credit under Section 631.b.3]
1. The portions of the community’s emergency plan that indicate evacuation
routes and procedures for notifying and evacuating critical facilities; and
2. A copy of the materials that notify occupants of the dam failure inundation
area as discussed in Section 631.b.3. The materials must be distributed
each year and must reach at least 90% of the properties in the dam failure
inundation area. An outreach project to the community or to floodplain
properties credited under Activity 330 (Outreach Projects) may qualify for
this credit provided that it explains the dam failure hazard, the area
affected, evacuation routes, and appropriate flood safety topics.

The appropriate sections of the plan should be marked with the acronym “DFP3.” Some or all
of this documentation may have been provided for Activity 330 (Outreach Projects).
Annual Recertification
Each year, a CRS community must submit an annual recertification to FEMA through
its ISO/CRS Specialist. For continued credit for DFP, the recertification must include a
statement that an exercise has been conducted for the dam failure emergency response
plan, that regular communications checks between the community and the dam have
been made, and that the community has received an annual report from the dam
owner/operator. This recertification is due by October 1. The ISO/CRS Specialist
provides the forms with specific instructions.
Common Problems
This element requires documentation from the community emergency manager. The CRS
Coordinator cannot provide documentation for this element without assistance from someone
who is familiar with the community’s emergency response plan.
Some communities have tried to receive credit for providing the EAP for an upstream dam.
While information from the EAP is needed to develop the community’s emergency response
plan, DFP credit is for the community’s own plan.
Some communities have applied for DFP credit without a dam failure inundation map and
flood arrival times. They may have a generic emergency response plan that includes
exercises, dissemination, and other information, but without the dam failure inundation area
the plan does not receive CRS credit.
Some communities have difficulty documenting the monthly communications checks required
in DFP1. In some cases, communications between the community and the dam are so frequent
and routine that they are not mentioned in the emergency response plan. In this case, a letter
from the emergency manager describing the communications checks will provide sufficient
documentation.

Credit for Dam Safety

− 13 −

Edition: 2006

632 Impact Adjustment
The CRS measures the impact of an activity on the community. It does not matter who
owns an upstream dam, or if the dam safety emergency plan is developed by the
community or the county. What counts is that the community has a positive way to
receive notification of a potential dam failure, that the community knows what areas
are likely to flood if there is a failure, and that the community is prepared to take action
when it is threatened by a dam failure.
To simplify the CRS application process, the impact adjustment is not included in the
CRS Application. The ISO/CRS Specialist will help the community determine the
impact adjustment for dam failure planning.

There is no impact adjustment for SDS.
a. Option 1 (for DFP):
If the dam failure emergency plan covers all buildings in the SFHA, the
impact adjustment ratio rDFP = 1.0.

If all buildings in the Special Flood Hazard Areas (SFHAs) on the community’s Flood
Insurance Rate Map (FIRM) are on streams with upstream dams, and if dam failure
emergency plans have been developed for all upstream dams, the community should use
Option 1 for rDFP. If any of the community’s SFHA is coastal, and there are buildings in that
part of the SFHA, the community cannot use Option 1.

Example: Community 1 has one stream on its FIRM. The total number of
buildings in the SFHA is 100. bSF = 100
There is a flood control dam on the stream. The owner produced an EAP,
which Community 1 used to develop the dam failure portion of its emergency
response plan. Since all buildings in the SFHA are covered by the dam failure
emergency plan, Community 1 uses Option 1. rDFP = 1.0.

b. Option 2 (for DFP):
If only some of the buildings in the SFHA are covered by the dam failure
emergency plan, the community may use the default value rDFP =0.25.

The default value provides 25% of the credit the community has for DFP. If more than
25% of the buildings in the community’s SFHA are in dam failure inundation areas,
and the community cannot use Option 1, it should use Option 3.

Credit for Dam Safety

− 14 −

Edition: 2006

Example: Community 2 has two streams on its FIRM. One is a large river
and the other is a small tributary. The total number of buildings in the SFHA is
150, of which 20 are in the floodplain of the tributary.
Community 2 uses Option 2. rDFP = 0.25.

c. Option 3 (for DFP):
The impact adjustment ratio rDFP is computed by dividing the number of
buildings covered by the dam failure emergency response plan by the total
number of buildings in the SFHA (bSF):
rDFP = bDFP ,
bSF

where

bDFP = the number of buildings covered by the dam failure emergency
response plan, and
bSF = the number of buildings in the SFHA.
rDFP cannot be greater than 1.0.

If some of the SFHA is covered by a dam failure emergency plan, the community will
maximize its credit for this element by using Option 3 to determine the impact adjustment. To
calculate rDFP using Option 3, the community must know how many buildings are in its
SFHA (bSF) and how many buildings are within the dam failure inundation areas that have
DFP credit (bDFP).
Note that for any watercourse, if the dam
failure inundation area is larger than the
100-year floodplain, the number of buildings
in the dam failure inundation area may be
greater than the number of buildings in the
SFHA for that watercourse. Therefore, it is
possible that a community can earn full
credit for this element even if all of its
SFHA does not have a dam failure
preparedness plan. However, rDFP cannot
exceed 1.0, regardless of the calculation.

Credit for Dam Safety

Sections 302 and 303 of the Coordinator’s
Manual discuss ways to count buildings for CRS
credit. The number of buildings in the SFHA
(bSF) is also used to calculate credit for
Activities 310, 520, 530, 610, and 620. This is
also the number that should be on the
community’s biennial report to FEMA.
It is likely that the number of buildings in the dam
failure inundation area (bDFP) was determined
during development of the dam failure
emergency response plan. The emergency
manager is a likely source for this information.

− 15 −

Edition: 2006

Example: Community 3 has three streams on its FIRM. One is a large
river and the other two are small tributaries. The total number of buildings in
the SFHA is 150, of which 100 are in the floodplain of the large river. bSF =
150
There is a flood control dam on the large river. The owner produced an EAP
that Community 3 used to develop the dam failure portion of its emergency
response plan. The EAP indicates that the dam failure inundation area for the
large river is about the size of the 500-year floodplain.
The number of buildings in the dam failure inundation area for the large river
is 176. bDFP = 176

Community 3 uses Option 3 to calculate rDFP = bDFP = 176 = 1.17
bSF
150
Since rDFP cannot exceed 1.0, the community uses rDFP = 1.0 to calculate
its credit.

Credit for Dam Safety

− 16 −

Edition: 2006

633 Credit Calculation
The end result of this work is a score for the community’s dam failure emergency
response plan (DFP). It is the product of the credit points multiplied by the impact
adjustment ratio. In the Coordinator’s Manual it is shown as
cDFP = DFP x rDFP, where
cDFP is the final credit DFP;
DFP is the credit for the community’s dam failure response plan, which ranges
from 25 to 100; and
rDFP is the impact adjustment ratio, which ranges from 0.25 to 1.0.
cDFP can range from 6.25 to 100 points.
c630 = SDS + cDFP.

Credit for Dam Safety

− 17 −

Edition: 2006

634 Credit Documentation
a. State Dam Safety Program (SDS)
There is no documentation required for the community to receive credit points based on
the state’s dam safety program (SDS). The credit points will automatically be added to
the community’s credit, provided the state verifies the community’s compliance with
the state’s program.

b. Dam Failure Emergency Response Plan (DFP)
To receive credit for its dam failure emergency response plan (DFP), the community
must provide certain documentation to the ISO/CRS Specialist. The documentation
requirements are discussed in Sections 631.b and 632, above.

Credit for Dam Safety

− 18 −

Edition: 2006

635 For More Information
Most of the references listed below are on EAPs that are prepared by dam owners.
Information from an EAP, especially the dam failure inundation area map and arrival
times of the flood peaks, are needed for the community’s emergency response plan. The
dam failure emergency response plan itself is prepared just like the emergency
response plan for any other hazard, based on the specific hazard the community faces.
Alaska Department of Natural Resources, Division of Mining, Land & Water Dam
Safety and Construction Unit, 2003. Guidelines for Cooperation with the Alaska Dam
Safety Program.
http://www.dnr.state.ak.us/mlw/water/dams/AK_Dam_Safety_Guidelines092603.pdf

Arizona Department of Water Resources, 2002. Simplified Emergency Action Plan
Form, ADWR, Phoenix, AZ.
Federal Emergency Management Agency, 1998. Federal Guidelines for Dam Safety:
Emergency Action Planning for Dam Owners, FEMA-64. FEMA, Washington, D.C.
Pennsylvania Department of Environmental Protection, 2002. Guidelines for
Developing an Emergency Action Plan for Hazard Category 1 & 2 Dams. Harrisburg,
PA. http://www.dep.state.pa.us/dep/deputate/watermgt/WE/DamProgram/EmActPlan/Main.htm
San Diego County Office of Disaster Preparedness, 2000. Unified San Diego County
Emergency Services Organization Operational Area Emergency Plan.
Sylvester, Arthur G. 2006. “Teton Dam Failure.” Slide show posted on the website of
the Geological Sciences Department, University of California at Santa Barbara.
http://www.geol.ucsb.edu/faculty/sylvester/Teton%20Dam/welcome_dam.html

Washington State Department of Ecology, Dam Safety Section, 1998. Example EAP.
http://www.ecy.wa.gov/programs/wr/dams/exameap.html .
Wisconsin Department of Natural Resources, no date. Sample Emergency Action Plan,
Wisconsin DNR, Madison, WI. http://www.dnr.state.wi.us/org/water/wm/dsfm/dams/
documents/damseap.pdf

Credit for Dam Safety

− 19 −

Edition: 2006

[This page intentionally blank.]

Credit for Dam Safety

− 20 −

Edition: 2006

APPENDIX A
ELEMENTS OF AN EMERGENCY ACTION PLAN
An EAP includes a description of the dam and a set of specific actions to be taken by the
dam owner/operator if there is a dam failure or a threat of one. There may be related
actions to be taken by others, but the primary emphasis is on actions to prevent or delay a
dam failure and to notify agencies and facilities that may be affected by it.
It is virtually impossible for a community to properly prepare for a dam failure
emergency without an EAP prepared by the dam owner. It should also be apparent that
downstream communities should participate in the development of EAPs for all dams
upstream from them. The communities certainly need to know that they are included in
the dam owner’s/operator’s notification list. They should also be aware of the nature of
the dam failures that are forecast and the assumptions used to develop them. Finally, the
community should be sure that it always has the latest revision of the EAP.
Although the community is not responsible for the preparation of EAPs unless it owns
dams, it is important that community officials understand what is included in an EAP.
There are many models for EAPs, just as there are for community emergency response
plans, but they have many common elements.

Statement of Purpose
From Dam Safety Guidelines, Part III, An Owner’s Guidance Manual, Washington State
Department of Ecology:
Although most dam owners have a high level of confidence in the
structures they own and are certain their dams will not fail, history has
shown that on occasion dams do fail and that often these failures cause loss
of life, injuries and extensive property damage. A dam owner should
prepare for this possibility by developing an emergency action plan which
provides a systematic means to:
• Identify emergency conditions threatening a dam
• Expedite effective response actions to prevent failure
• Reduce loss of life and property damage should failure occur.
A dam owner is responsible for preparing a plan covering these measures
and listing actions that the owner and operating personnel should take. He
should be familiar with the local government officials and agencies
responsible for warning and evacuating the public.
It is important that dam owners make full use of others who are concerned
with dam safety; emergency plans will be more effective if they integrate
the actions of others who can expedite response. People and organizations
with whom the dam owner should consult in preparing an emergency action
plan include numerous local participants, state and federal agencies.

Credit for Dam Safety

A-1

Edition: 2006

An EAP may have a statement of purpose that explains why it was developed. However,
many EAPs are strictly working documents that do not include such a statement. They
start immediately with contact lists or descriptions of emergency conditions.

Description of the Dam
This section includes a brief description of the watershed above the dam, the type of
construction, the storage capacity, a discussion of the spillway and other outlets, and the
normal operation of the dam. There is also a short description of the river and floodplain
downstream from the dam.
It is important for downstream communities and floodplain residents to understand some
of the characteristics of an upstream dam.
• A flood control dam is normally kept empty or nearly empty. When a flood arrives
from upstream, it releases water at a rate that will keep it from overtopping. These
releases may cause downstream flooding of roads and low areas, but they are
necessary to control and reduce the peak flow from upstream.
• A storage dam for water supply is normally kept as full as possible. It releases
water on a schedule for municipal or irrigation purposes. The operator of a storage
dam may only be able to release a small flow of water until the reservoir is full
and water flows over the spillway. In this case, the dam may do little to reduce
downstream flood peaks. That is not a decision the operator makes; it is inherent
in the design of the dam.
• Like a storage dam, a dam built primarily for the generation of electric power
needs to maintain a certain reservoir elevation for this purpose, and the ability to
release water when a large inflow is expected may be limited.
The normal operation of a dam affects the outcome of a dam failure.

Notification
A notification flow chart is a prioritized list of people and agencies the dam
owner/operator notifies whenever there is an emergency or a potential emergency that
could lead to a dam failure. This may be the first chapter of the EAP. This is the first
thing the dam operator needs to do in a dam failure.
This list may include dam maintenance staff and others who need to monitor the dam. It
will always include state dam safety officials and downstream communities. It may also
include specific facilities that need immediate notification, such as the operators of
recreational facilities adjacent to the river near the dam.
There may be two or more notification flow charts. One may be used when dam failure is
imminent or has already occurred. The priorities in this event are to notify facilities and
agencies downstream that a flood peak is coming and that they should take immediate
and appropriate actions to save lives and property. Another notification flow chart may

Credit for Dam Safety

A-2

Edition: 2006

be used when the dam owner/operator sees a situation developing that could lead to a
dam failure. The priorities and the messages to be used in this event vary according to the
situation.
The notification flow charts include names, telephone numbers, radio frequencies and
call signs, cell phone numbers, and other information on the people who need to be
contacted. There may be office and home numbers, and information for office hours and
after hours.
Like a community’s emergency response plan, each page in the EAP should have a
revision date. It is essential to keep these notification flow charts current.
Emergency Detection and Evaluation
Dams are regularly inspected, monitored, and maintained. Emergency situations may be
identified as a result of these inspections and monitoring. Other events, such as an
earthquake or a forecast of a large upstream flood, may signal an impending emergency.
During an emergency situation, extra efforts are made to monitor a dam. For example,
under normal conditions, the reservoir level may only change a few tenths of a foot per
day. Reservoir levels may be recorded hourly or daily. If there is a sudden drop in the
reservoir level, that signals an emergency. A large flood entering the reservoir may cause
the level to rise several feet in a matter of hours. In these situations, reservoir levels may
be recorded every few minutes.
Most large dams today have telemetered gages so that the dam operator can monitor the
dam and reservoir at all times. Typical measurements include the flow of the river above
the reservoir, the level of the reservoir, and the flow in the river downstream from the
dam. In some cases, there are instruments to measure movement of the dam, moisture
content inside an earthen structure, and other parameters of the dam itself.
During an emergency, it may be necessary for staff to take additional measurements, and
other data may be needed by the operator. For example, if the reservoir is nearly full and
a storm is expected above the dam, the operator may need rainfall data, weather radar
data, and streamgage data from gages far upstream from the dam.
The EAP tries to anticipate these data needs and provide procedures to meet them.

Responsibilities
Responsibilities are specified in the EAP for the dam owner/operator and staff. Their
primary responsibilities are to transmit warning messages according to the notification
procedures specified, to protect the dam from damage, and to limit downstream peak
flows as much as possible.
The emergency preparedness and response of downstream floodplain occupants is the
responsibility of the communities and facility managers. These should be coordinated

Credit for Dam Safety

A-3

Edition: 2006

with the dam owner/operator through the development and periodic revision of the EAP
to ensure that warning messages are clear and unambiguous, and that the appropriate
response will be made.

Preparedness
Emergency preparedness by the dam owner/operator includes
• Ensuring that data collection (and telemetry) equipment is functioning properly at
all times;
• If the dam is not staffed at all times, ensuring that there is a plan to respond

whenever there are no personnel at the dam;

• Ensuring that there is all-weather access to the dam;
• Ensuring that there are sufficient equipment and supplies for an emergency,

including food and water for the staff, at all times; and

• Ensuring that there are alternative means of communications from the dam to
decision makers.

Forecasts of Dam Break Floods
The engineering analysis for an EAP consists of determining the most probable mode of
failure for the various project features and preparing an inundation map for the affected
areas downstream of the dam. The EAP is to consider those things that cannot be forecast
such as instantaneous or rapid failures. Earthquakes, rapid dam or foundation failure,
penstock or spillway failure, and landslides are examples of the failure modes considered.
A Probable Maximum Flood emergency is not considered because advance warning
would be given by the weather. Based on engineering judgments, several assumptions are
made to produce a hypothetical worst dam breach flood. An emergency response can then
be prepared based on this hypothetical worst-case dam breach flood.
This section of the EAP should discuss the type of hydrologic and hydraulic models used
to determine the “hypothetical worst-case flood,” the assumptions made in the modeling,
and the results of the modeling. The results may include several scenarios, including the
cause of a dam failure, water level in the reservoir at the time of failure, current weather
conditions, etc.
The “results” section will generally include a table showing the expected peak flow at
different points downstream, travel times for the flood from the dam to these points,
maximum flood velocities and other information, and maps of dam failure inundation
areas. If there are a number of scenarios, there may be several of these tables. See the
fictitious example at the top of the next page.
These tables are essential to downstream emergency preparedness. As seen in the
fictitious example for Alamo Dam on page A-5, they provide estimates of the
downstream arrival time and peak flood elevations. Both of these factors are needed for

Credit for Dam Safety

A-4

Edition: 2006

the emergency manager to order effective evacuations. If there are several hours of
warning time, it may be possible for residents to remove some items of value. If the time
is shorter, it may be difficult even to get the people out of harm’s way.
Closely related to a data table like the one in this example, there may be a flood profile
for the dam failure(s). The figure on page A-6 is an example of a profile for the Trask
River in Washington. This profile shows the ground elevation and the elevations of the
10-, 100- and 500-year floods, probably from the Flood Insurance Study. It also shows a
“sunny day” dam break flood profile. Because this EAP was developed at least partially
because of a proposal to raise the height of the dam, it also shows flood elevations for
two dam break scenarios with the larger dam in place.

Alamo Dam
Extreme Wet Weather Break 1
Cross Section
(Miles from dam)

Peak Flow
(cfs)

Peak Water Level
(ft)

Travel Time
(hours) 2

Maximum Velocity
(feet/sec) 3

Alamo Dam (0.0)

1,250,000

Elev 2332

0.0

41.0

Highway 23 (7.8)

900,000

Elev 2251

0.7

12.5

Salt Creek (12.2)

725,000

Elev 2205

1.1

10.1

Highway 154
(20.5)

550,000

Elev 2140

2.5

9.8

Big River (28.6)

350,000

Elev 2102

4.0

8.7

1

2
3

Based on a Probable Maximum Flood (PMF) inflow to Alamo Dam and 100-year antecedent
flooding downstream from the dam.
Travel time is based on the start of water level rise at the cross section.
Velocity is average cross section velocity.

Inundation Maps
Maps showing the area that will be inundated are the
final parts of the EAP that are essential to downstream
emergency preparedness and response. The example to
the left shows a rudimentary dam failure inundation
map for a fictitious dam. The area inside the inner
lines is the 100-year floodplain. The area inside the
outer lines is the dam failure inundation area.
The map on page A-7 shows an actual dam failure
inundation area for an area downstream from a dam on the Trask River in Washington.
There is a lot of information on this map that will help in emergency preparedness
planning and emergency response.

Credit for Dam Safety

A-5

Edition: 2006

First, the note in the upper left hand corner explains that the information on this map is
approximate. If the emergency manager has reason to believe that the flood approaching
this area is larger than that used to develop this map, he or she may need to evacuate a
larger area. This map shows the area expected to be inundated by a dam failure flood.
This map can help the emergency manager plan evacuation routes, areas needing
evacuation, and emergency shelters.
The map also shows the 100- and 500-year floodplains. This is useful to indicate that a
dam failure on this river would cause a much larger flood than residents have ever seen.
Note that the map shows the cross section number that would be related to a table similar
to the example on the top of this page. For each cross section, there is a line showing
where the cross section is located, what the cross section number is, and the times when
water is expected to start to rise and when the peak flow is expected to arrive.

Credit for Dam Safety

A-6

Edition: 2006

A profile for the Trask River, Washington.

Credit for Dam Safety

A-7

Edition: 2006

An inundation area map for Barney Dam, Washington.

Credit for Dam Safety

A-8

Edition: 2006

APPENDIX B
AN EXAMPLE OF CRS CREDIT FOR
A LOCAL DAM FAILURE EMERGENCY PLAN
NOTE: The examples in this appendix are from a real county emergency plan. For
security reasons, the county emergency manager asked that information on the threat
posed by dam failures in the county not be widely disseminated. Therefore, all place
names and some geographic facts have been altered to disguise the identity of the
community and the dams.

The Jones County Emergency Management Plan has been adopted by both Jones County
and Jones City. Although it is an all-hazards plan, it has a separate document called the
“Jones County Flood Contingency Plan.” This document, which includes the dam failure
plan, is in a 2-inch ring binder.
The first section of the plan includes the purpose, legal authority, general responsibilities
for various city and county agencies and others, and other general information.
The second section, “Implementing Procedures,” includes emergency phone numbers,
levels of response, public protection strategies, and public information messages for
evacuation and other actions.
The third section of the Flood Contingency Plan includes more detailed information on
the Jones River, the largest river that flows through the population centers in the county.
It has a more specific list of responsibilities and flood data and maps for the Jones River.
The fourth section has detailed information on several tributaries to the Jones River.
Since these cause different flood problems in different areas of Jones City and Jones
County, the specific responsibilities are somewhat different.
The fifth section of the plan discusses dams that affect the county. This is discussed in
more detail below.
The sixth section has detailed information on another large river in the county that runs
through rural areas.
Here is how Jones County documents its dam failure plan and the CRS credit it receives
for DFP in Activity 630.

Credit for Dam Safety

B-1

Edition: 2006

631 Credit Points
Section 631.b in the Coordinator’s Manual specifies the following:

b. Dam failure emergency response plan (DFP) (Maximum credit: 100 points)
DFP = DFP1 + DFP2 + DFP3
1. DFP1 = 25, if the community has the following:
(a) An emergency response plan that
(1) Specifies that the community will be notified in the event of an
impending or actual failure of a dam upstream from the community;
(2) Provides projected inundation areas, flood elevations, and estimated
arrival times for flood peaks arising from a failure of the dam; and
(3) Calls for an exercise at least annually. The results of the exercise are
evaluated and used to revise the response plan.

The Jones County Emergency Manager has copies of the EAPs prepared by the
owner/operator of the three dams upstream from Jones City on the Jones River. Although
each dam has a capability of operation at the dam, the dams are normally monitored and
operated remotely from an operations center in Jones City. Each of the EAPs includes
notification of the Jones County Emergency Management Office in the event of any
emergency situation that might affect the county. These EAPs are updated annually.
The Jones County Flood Contingency Plan includes tables and maps showing dam failure
inundation areas, flood elevations, and flood arrival times at various points downstream
from each dam.
Although the Flood Contingency Plan itself does not call for annual exercises, it states
that “the Jones City-County Emergency Management Office, through the Local
Emergency Planning Committee, is responsible for scheduling, designing, conducting and
evaluating flood incident exercises.” A separate resolution of the Local Emergency
Planning Committee states that the City-County Emergency Plan will be exercised at
least annually, and there is documentation that there have been four exercises in the last
three years. Three of these exercises were flood-related and one was a simulation of a
plane crash near the airport.

(b) A procedure to obtain annual reports by the dam operators on the safety
and operational status of their dams. Copies of these reports must be
sent to the community and the state dam safety office; and

Credit for Dam Safety

B-2

Edition: 2006

During the verification visit, the County Emergency Manager demonstrated that the
safety and operational status of the dams is maintained on the internet by the
owner/operator of the dams, and is monitored daily by emergency management staff.

(c) Monthly communication checks between dam operators and emergency
services officials.

County emergency management staff are constantly in communication with the dam
operators. During normal operations, this communication is by telephone. During a dam
failure emergency, the EAPs and the Jones County Flood Contingency Plan both specify
that a liaison person will be stationed in the City-County Emergency Center with radio
communications with the dams.
DFP1 = 25

2. DFP2 = 25, if the community has the following:
(a) credit for DFP1, and
(b) an adopted emergency plan that details at least three methods of
notifying affected residents of an imminent flood event resulting from a
possible or ongoing dam failure. At least three of the following
notification methods must be available:
• Sound or voice siren system.
• Telephonic notification, AM transmitters and receivers dedicated to
dam failure notification.
• NOAA Weather Radio. Receivers with Specific Area Message
Encoding (SAME) are preferred.
• Mobile public address.
• Emergency Alert System.
• Cable television override.
• Door-to-door notification.

The first page of the Jones County manual is a joint resolution signed by the city and the
county, adopting the plan in 1995.
The Flood Contingency Plan lists the following methods for alerting the public:
• National Weather Service,
• NOAA Weather Radio (CRS credit),
Credit for Dam Safety

B-3

Edition: 2006

•

Emergency Alert System (CRS credit),

•

Television and radio news broadcasts,

•

Vehicles equipped with loudspeakers (CRS credit), and

•

Door-to-door notification (CRS credit).

Since the county has four creditable methods for notification,
DFP2 = 25

3. DFP3 = 50, if the community:
(a) Has credit for DFP1 and DFP2;
(b) Has an adopted emergency plan that includes evacuation routes and
detailed procedures for notifying and evacuating critical facilities,
specifically including schools, hospitals, nursing homes, jails, and other
locations where there are populations that may have difficulty
evacuating the dam failure inundation area; and
(c) At least annually notifies occupants in the dam failure area of the
hazard, the area affected, evacuation routes, and flood safety topics
appropriate to the hazard.

Although the Flood Contingency Plan has a detailed list of critical facilities, there is
generalized information on how some of them should respond, and they have notification
lists, there are no detailed procedures for evacuating these facilities. Also, perhaps
because all of downtown Jones City is within the dam failure inundation area, annual
notifications are not made to occupants of this area.
DFP3 = 0
DFP = DFP1 + DFP2 + DFP3
For Jones County, DFP = 25 + 25 + 0 = 50

Credit for Dam Safety

B-4

Edition: 2006

632 Impact Adjustment
a. Option 1:
If the dam failure emergency plan covers all buildings in the SFHA, the impact
adjustment ratio rDFP = 1.0.
b. Option 2:
If only some of the buildings in the SFHA are covered by the dam failure
emergency plan, the community may use the default value rDFP =0.25.
c. Option 3:
The impact adjustment ratio rDFP is computed by dividing the number of
buildings covered by the dam failure emergency response plan by the total
number of buildings in the SFHA (bSF):
rDFP = bDFP ,
bSF

where

bDFP = the number of buildings covered by the dam failure emergency
response plan, and
bSF = the number of buildings in the SFHA.
rDFP cannot be greater than 1.0.

Because there are no dams on several tributaries of the Jones River in Jones County, the
county cannot use Option 1. It chooses Option 3 to determine rDFP.
Jones County had to determine the number of buildings in its Special Flood Hazard Areas
(bSF) for Activity 520. It determined that bSF = 227 for the county.
The dam failure inundation area for the worst-case dam failure on the Jones River
includes 1,117 residences and 84 non-residential structures. bDFP = 1,117 + 84 = 1,201.
rDFP = 1,201 = 5.29. Since rDFP cannot exceed 1.0, the county uses rDFP = 1.0.
227
Note that Jones County uses rDFP = 1.0 even though there are portions of its SFHA that
have no dam failure planning. This is because the dam failure inundation area is larger
than the SFHA on the Jones River, and there are buildings within the dam failure
inundation area that are not in the SFHA but that do benefit from the county’s dam
failure planning.

Credit for Dam Safety

B-5

Edition: 2006

633 Credit Calculation
cDFP = DFP x rDFP
cDFP = 50 x 1.0 = 50

Credit for Dam Safety

B-6

Edition: 2006