Historical Flood Check

DOE-STD-1023-95

Case 1: Peak flood based on runoff analysis due to rain and snow

melting.

Case 2: Ponding on roof.

Case 3: Peak ground water level and Case 1.

If the hazard annual probability of exceedance for a primary potential flood source is less than the

maximum annual flood hazard exceedance probabilities acceptable for the PC, it need not be

considered.

The combination of the potential flood sources is assumed to be perfectly correlated for the purpose

of developing flood hazard curves.

3.3.5 Historical Flood Check

In assessing the conservatism in the proposed DBFL, the review will consider historical flooding that

may have affected the site and ensure that the proposed DBFL conservatively accounts for a

recurrence of the event causing the flooding. Since the hydraulic characteristics of the basin might

have changed since the maximum historical flood, the flood level itself may not be able to form a

direct comparison to the DBFL. Rather, the amount of water produced, or the rainfall intensity and

distribution, should be compared to the event leading to the DBFL. For PC-3 and PC-4 facilities, the

DBFL event should be equal to or greater than the maximum historical event in the basin.