A sandbag is a sack made of burlap or woven polypropylene that is filled with sand or soil and used for such purposes as flood control and military fortification. Sand bags are an excellent choice for the construction of levees, berms, dikes and barricades for erosion control, flood walls, and traffic control. Sandbags may be used during emergencies when rivers threaten to over-flood, or a levee or dike is damaged. Quick action and bags on-hand could save countless dollars in personal and property damage.
The use of sandbags is a simple, but effective way to prevent or reduce flood water damage. Properly filled and placed sandbags can act as a barrier to divert moving water around, instead of through, buildings. Sandbag construction does not guarantee a water-tight seal, but is satisfactory for use in most situations. Sandbags are also used successfully to prevent overtopping of streams with levees, and for training current flows to specific areas.
Sandbags alone should not be relied on to keep water outside a building. Use baffle boards (plywood sheeting) or sheets of plastic tarp with sandbags. To form a sandbag wall, place bags tightly against one another to form the first layer of defense. Stagger the second and subsequent layers of bags, much like the pattern of bricks in a wall.
Sandbags, when properly filled and placed, will redirect storm and debris flows away from property improvements.
Woven Polypropylene When treated for UV exposure, commercial plastic (polypropylene) sandbags are available. They provide the strongest material for flood control, levee, trench and berm construction and all temporary or permanent protective barriers. When covered from ultra violet exposure, Polypropylene Sandbags last almost indefinitely with a minimum of care, but are not biodegradable. Thus they have to be disposed of, or will remain around a long time.
Use bags about 14-18" wide, and 30-36" deep. Sandbags should be filled half full for easy stacking and will weigh approximately 30 pounds. Thirty sandbags are equal to approximately ½ ton (one ton is 2000 pounds) and is the maximum legal load limit for a ½ ton truck.
It takes an average of 600 sandbags to cover a 100 foot section, 1-foot high.
A heavy bodied or sandy soil is most desirable for filling sandbags, but any usable material at or near the site has definite advantages. Coarse sand could leak out through the weave in the bag. To prevent this, double bag the material. Gravelly or rocky soils are generally poor choices because of their permeability. Filled bags of earth material will deteriorate quickly.