Flood Screening Analysis

DOE-STD-1023-95

For determination of the DBFL, the flood hazard assessment shall consider the possibility of

simultaneous occurrence of flood events as specified in Section 3.3.4 of this Standard.

In completing a flood hazard assessment, it is extremely important that a site-specific data base be

available. DOE-STD-1022-94 provides criteria for the types of data that shall be collected and

compiled for such a data base.

3.3.2 Flood Screening Analysis

The objective of the flood screening analysis is to conduct a preliminary flood hazard assessment that

identifies potential flood hazards including flood induced rise in ground water and to determine

whether flooding can take place or whether the site can be considered a flood-dry site (ANS, 1987).

A flood-dry site is defined as one where the structures are physically removed from the potential

sources of flooding so that safety from flooding is obvious and can be documented with minimal

effort.

In the case of flood-dry sites, the flood screening analysis will conclude that flooding is not a design

basis event.

In the case of non-flood-dry sites, the flood screening analysis will provide a preliminary measure of

the magnitude and probability of occurrence of extreme floods.

The flood screening analysis includes the following three steps:

Step 1:

Identification of the sources of flooding.

Step 2:

Evaluation of flooding potential.

Step 3:

Preliminary flood hazard analysis.

Examples of acceptable previous flood screening analyses for 10 DOE sites are presented in McCann

and Boissonnade (1988a, 1988b, and 1991) and summarized in Savy and Murray (1988). The

elements comprising a flood screening analysis are further described in Appendix A.

3.3.3 Comprehensive Flood Hazard Assessment

Results of the flood screening analysis determine whether floods could impact DOE operations. For

sites that could be exposed to flooding and do not meet the design basis, a comprehensive flood

hazard analysis is required. The need to perform a site comprehensive hazard assessment depends on

the potential DBFL impact on the facilities for the flood hazard exceedance probabilities. Guidelines

to evaluate these impacts are provided in DOE-STD-1020-2002. These guidelines recommend the

design basis for DOE facilities based on the following factors:

(1)

Types of potential flood hazard

(2)

Performance Category