Table E-2 Causes of Flooding

DOE-STD-1020-2002

flood hazards. In most cases, the principal hazard of interest is submergence or inundation.

However, the damage potential of a flood is increased if there are impact or dynamic forces,

hydrostatic forces, water-borne debris, etc. Table E-2 lists the various sources or causes of

flooding that can occur and the particular hazards they pose. From the table, one notes that

many of the causes or sources of flooding may be interrelated. For example, flooding on a river

can occur due to dam or levee failure or to precipitation.

In most cases, flood hazards are characterized in terms of the depth of flooding that

occurs on site. Depth of inundation is the single most relevant measure of flood severity.

However, the degree of damage that is caused by flooding depends on the nature of the hazard.

For example, coastal sites experience significant damage due to wave action alone, even if the

site is not completely inundated by a storm surge. Similarly, high-velocity flood waters on a

river add substantially to the potential for loss of life and the extent of structural damage. In

many cases, other hazards - such as wave action, sedimentation, and debris flow - can compound

the damage caused by inundation.

Table E-2 Causes of Flooding

Source/Cause

Hazard

River flooding/precipitation,

snow melt, debris jams, ice

Inundation, dynamic forces, wave action, sedimentation, ice loads

jams

Dam failure/earthquake,

flood, landslide, static failure

Inundation, erosion, dynamic loads, sedimentation

(e.g., internal erosion, failure

of outlet works)

Levee or dike

failure/earthquake, flood,

Inundation, erosion, dynamic loads, sedimentation

static failure (e.g., internal

erosion, subsidence)

Precipitation/storm runoff

Inundation (ponding), dynamic loads (flash flooding)

Tsunami/earthquake

Inundation, dynamic loads

Seiche/earthquake, wind

Inundation, dynamic loads

Storm surge, usually

accompanied by wave

Inundation, dynamic loads

action/hurricane, tropical

storm, squall line

Wave action

Inundation, dynamic loads

Debris

Dynamic loads

E-9