FLOOD06918

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: The NWS Simplified Dam Break-Flood Forecasting Model
• Date: 5/16/1986
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

Preface

The Federal Emergency Management Agency (FEMA) is responsible
for the coordination of federal efforts to promote dam safety.
To accomplish this goal, the National Dam safety Program has
been developed under FEMA's direction. The Program addresses
two areas which must be carefully integrated: federal programs
for enhancing the safety of federal and nonfederal dams and
nonfederal programs to protect the public from the hazards of
non federal dams.

The problems of nonfederal dams are greater than those faced
with federal dams. There are over 68,000 dams in the United
states. About 95 percent, or 63,400, are nonfederal. Based on
an inspection of nonfederal dams completed in 1981 by the Corps
of Engineers, 8,639 dams constitute a high hazard potential to
the downstream public. Of these, about 2,884 were judged to be
unsafe. Thus, the major problem with unsafe dams rests with
with the nonfederal owners.

The owner of a dam is responsible for its safety. However,
most of the nonfederal dams are privately owned (versus
corporate or government owners). Many of these owners find
the responsibilities of ownership beyond their financial
capability. States also have responsibilities. These include
providing a regulatory framework that informs the owners in
advance of the responsibilities and liabilities of ownership
and that enforce appropriate regulations. Only about 22 states
have adequate dam safety programs which provides this
leadership.

FEMA has undertaken a lead coordination role in encouraging and
effecting the transfer of technical assistance to assist States
and owners in dealing with their responsibilities.

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Owners of dams must recognize the need to work with downstream
populations to minimize the impact of flooding in the event of
a dam failure or accident. The emergency manager,responsible
for the preparedness of that population, must likewise develop
warning systems, in cooperation with the dam owner, and
evacuation plans which respect the unique nature of a
dam-induced flood.

The linchpin of emergency plans to respond to dam accidents or
failures is knowing in advance the areas potentially flooded.
The inundation area takes on great importance. In the past,
the modeling necessary to predict with precision the areas
likely to be flooded by a dam break were computer intensive and

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