Geology and Soil Mechanics, UW-Stout

Flooding and Construction

Every year flooding causes more property damage in the United States than any other type of natural disaster. There are more than 6 million dwellings and a large number of non-residential buildings are currently located in the nation’s 160 million acres of flood prone area. Historically, people have settled next to waterways because of the advantages in transportation, commerce, energy, water supply, soil fertility, and waste disposal. In recent times, tourism and recreation is drawing a large number of people to waterways.

The problem arises when economic development and construction fail to take sufficient precautions to avoid flood damage. This is a question of economic costs verses the benefits. To reduce the effect flooding has on the loss of life and property we must (i.) design the structure (or drainage) to reduce flood damage, (ii.) apply flood control measures (i.e. dams and levees), and/or (iii.) prohibit rebuilding or initial construction in flood prone areas. Many "at-risk" communities participate in the NFIP (National Flood Insurance Program). Flood insurance is made available to property owners in participating communities. In return, they adopt and enforce land-use and floodplain management ordinances.

For more information see the following documents:

National Flood Insurance Program from FEMA
Flood Resistant Design Construction Publications from FEMA
Avoiding Flood Damage: A Checklist For Homeowners from FEMA (Adobe Acrobat format)
Examples of Flood Mitigation with QuickTime movies (Lozoff Home, Crisler Mobile Home)
FEMA Flood Preparedness and Safety Tips
Some FEMA publications that are free by calling 1-800-480-2520: 
    FEMA - 15: Design Guidelines for Flood Damage Reduction
    FEMA - 54: Elevated Residential Structures
    FEMA - 114: Design Manual for Retrofitting Flood-Prone Residential Structures
    FEMA - 235: Repairing Your Flooded Home

Flooding and water accumulation is a particular hazard at a construction excavation site. OSHA requirements indicate that:

(1) Employees shall not work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees against the hazards of water accumulation. Some precautions include special support or shield systems to protect from cave-ins, water removal to control the level of accumulating water, and/or use of a safety harness and lifeline.

(2) If water is controlled or prevented from accumulating by the use of water removal equipment, the removal equipment and operations shall be monitored by a competent person to ensure proper operation.

(3) If excavation work interrupts the natural drainage of surface water (such as streams), diversion ditches, dikes, or other suitable means shall be used to prevent surface water from entering the excavation and to provide adequate drainage of the area adjacent to the excavation.

Or see the OSHA manual on Excavations: Hazard Recognition in Trenching and Shoring and scroll down to the topic Protection from the hazards associated with water accumulation (h1) .

For questions or comments regarding these pages contact Dr. Alan Scott / / this page was last updated July 09, 2002