FLOOD06680

• County: Statewide
• Basin: Statewide
• Title: Flood Damage in the United States, 1926-2000
• Date: 6/1/2000
• Prepared By: NOAA
• Floodplain - Doc Type: Flood Documentation Report

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2. SOURCES OF FLOOD DAMAGE ESTIMATES, 1926-2000

For nearly a century, the NWS and its predecessor, the U.S, Weather Bureau, have
collected flood damage estimates through a nationwide system of field offices. The quality of
the flood damage estimates is uneven, depending on operational constraints at particular field
offices and diverse sources of damage reports, Policies and procedures for collecting and
compiling the estimates have changed somewhat in the course of time,

A. Overview of Historical NWS Estimates
The NWS has published flood damage estimates almost annually since 1933, From 1933
to 1975, reporting units were defined by natural boundaries (river basins), which could be useful
for local planning on issues such as water supply, agriculture, and flood contro1. In 1955, annual
summaries of damage by state were added, Consistent administration, methodology, and format
of the published reports suggest that these data form a reasonably homogeneous time series,

From 1976 through 1979, reduction of funding led to cutbacks in the compilation of flood
damage data, Data collection was consistent with prior years, but there appears to have been less
checking and updating of initial damage information, Publication of annual summaries ceased,
In 1980, compilation of flood damage estimates was discontinued entirely,

In 1983, Congress ordered the U.S, Army Corps of Engineers (USACE) to provide annual
reports of flood damage suffered in the V,S, The USACE contracted with the NWS to provide
the required data, NWS estimates of flood damage in each state have been published annually
since 1983 by the USACE. The NWS Hydrologic Information Center (NWS-IDC) has gradually
improved its procedures for compiling and checking the damage estimates.

The long-term consistency in collection of flood damage data results from its connection to
weather forecasting and storm warning operations of the NWS, Since at least 1950, reports on
severe storms have been submitted regularly to NWS headquarters from field offices distributed
across the U,S, The reports include descriptions of severe storms and associated deaths and
damage, Since 1959, these reports have been published monthly in a NOAA periodical, Storm
Data, and have provided the initial information used in compiling flood damage estimates,
However, the field office reports are filed soon after the storm events and receive only minimal
quality control before publication, thus the damage estimates provided are preliminary and
incomplete, Staff at NWS headquarters perform considerable checking and follow-up to produce
final flood damage estimates,

This brief overview highlights a major change in the purpose and format of the flood
damage data, Before 1980, the NWS compiled damage estimates for meteorological and
hydrological purposes, based on natural units such as watersheds, Annual estimates were
compiled by calendar year. Since 1983, the USACE and NWS have prepared flood damage
information for Congress, whose members focus on the state as a political unit, Estimates are
compiled by federal fiscal year,