Table 4-1 Flood Criteria Summary

DOE-STD-1020-2002

Table 4-1 Flood Criteria Summary

Performance Category

Item

Flood

Flood insurance stu-

Site probabilistic haz-

Hazard

dies or equivalent

ard analysis, including

Input

input, including the

the combinations in

combinations in Table

Table 4-2

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Mean Hazard

Annual

2x10-3

5x10-4

1x10-4

1x10-5

Probability

Design

Applicable criteria (e.g., governing local regulations, IBC 2000) shall be used for building design for

Requirements

flood loads (i.e., load factors, design allowables), roof design and site drainage. The design of

flood mitigation systems (i.e., levees, dams, etc.) shall comply with applicable standards as referred

to in these criteria.

Emergency

Required to evacuate

Required to evacuate on-site personnel not

Operation

on-site personnel if

on-site personnel and

involved in essential operations. Provide for an

Plans

facility is impacted by

to secure vulnerable

extended stay for personnel who remain.

the DBFL

areas if site is

Procedures must be established to secure the

impacted by the DBFL

facility during the flood such that operations may

continue following the event.

4.1.1 Design Basis Flood (DBFL)

As part of the flood hazard assessment1 that is performed for a site, the sources of

flooding (e.g., rivers, lakes, local precipitation) and the individual flood hazards (e.g.,

hydrostatic forces, ice pressure, hydrodynamic loads) are identified. A site or individual SSC

may be impacted by multiple sources of flooding and flood hazards. For example, many DOE

sites must consider the hazards associated with river flooding. In addition, all sites must design a

stormwater management system to handle the runoff due to local (on-site or near site)

precipitation. Events that contribute to potential river flooding such as spring snowmelt,

upstream-dam failure, etc. must be considered as part of a probabilistic flood hazard analysis.

Therefore, at a site there may be multiple DBFLs that are considered. For sites with potential for

river flooding a DBFL is determined for river flooding and for local precipitation which

determines the design of the site stormwater management systems. (Note, for sites located on

rivers or streams, the meteorologic and hydrologic events that produce intense local precipitation

are often distinct from those which produce high river flows). In this instance, various aspects of

the design for a SSC may be determined by different flood hazards. As a result, the term DBFL

is used in a general sense that applies to the multiple flood hazards that may be included in the

design basis.

Guidelines for conducting a probabilistic flood hazard assessment are contained in (DOE-STD-1023).

The analysis includes an evaluation of the hydrologic and hydraulic characteristics of a site and site

region. As part of the probabilistic assessment, an evaluation of uncertainty is also performed.

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