Sandbag structures do not prevent water seepage and therefore should be built with the central purpose of diverting flood water around or away from buildings. Sandbags can also be used to fortify existing flood control structures and limit the effects of sand boils. Sandbags can be used to build levees, barricades, dikes and berms to limit erosion from flooding. Properly stacked sandbags are an effective deterrent against damaging flood waters. Usage Troops from the Grenadier Guards constructing sandbag defenses around government buildings in Birdcage Walk, London, May 1940. Since the 1990s, machine filling has become more common, allowing the work to be done more quickly and efficiently. Sandbags have traditionally been filled manually using shovels. In a military context, improvised up-armouring of tanks or armored personnel carriers with sandbags is not effective against cannons (though it may offer protection against some small arms). They can also become contaminated by sewage in flood waters making them difficult to deal with after flood waters recede. They can degrade prematurely in the sun and elements once deployed. Without proper training, sandbag walls can be constructed improperly causing them to fail at a lower height than expected, when used in flood-control purposes. Disadvantages are that filling bags is labor-intensive. They can be brought to a site empty and filled with local sand or soil. When empty, the bags are compact and lightweight for easy storage and transportation. The advantages are that the bags and sand are inexpensive. Members of the Georgia National Guard filling sandbags in preparation for floods.Ī sandbag or dirtbag is a bag or sack made of hessian (burlap), polypropylene or other sturdy materials that is filled with sand or soil and used for such purposes as flood control, military fortification in trenches and bunkers, shielding glass windows in war zones, ballast, counterweight, and in other applications requiring mobile fortification, such as adding improvised additional protection to armored vehicles or tanks. Residents and volunteers work to fill sandbags during the Mississippi and Missouri river floods of 1993. JSTOR ( June 2008) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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