New York State Division of Homeland Security & Emergency Services
Proper Sandbagging Techniques
Content provided by the U.S. Army Corps of Engineers, St. Paul District (MN) and NYS Department of Environmental Conservation.
Sandbagging can be an effective flood-fighting tool and is a simple, effective way to prevent or reduce flood water damage. Although sandbags do not guarantee a watertight seal, they are a proven deterrent to costly water damage. Proper sandbag filling and placement methods increase productivity of sandbagging operations. Below are safety tips and proper procedures that are designed to minimize work-related injuries and maximize essential time.
Follow the tips below to ensure safety for ALL personnel:
- Use proper lifting techniques to avoid injury and fatigue. Lift with your legs and bend at the knees to avoid injury to your back.
- Sandbags are treated to prevent deterioration when stored. Use work gloves and avoid contact with your eyes and mouth. Always wear safety goggles or glasses.
- Stay in eye contact with heavy equipment operators and keep alert for truck backup alarms.
- Flood waters can be polluted. Use rubber gloves and appropriate clothing if contact with water is unavoidable.
- The most commonly used bags are treated burlap or woven polypropylene about 24 inches by 14 inches. Unused empty bags can be stockpiled for emergency use and will be serviceable for years, if kept dry and properly stored out of the sun and weather. Filled bags of earth material will deteriorate quickly. In an emergency any kind of bags can be used.
- Untied sandbags are recommended for most situations. Tied sandbags should be used only for special situations or for specific purposes such as filling holes, holding visquine or straw bales in place or to form barriers backed by supportive planks or aluminum sheet piles.
- Untied bags should be filled approximately 2/3rds full. Tied bags can be filled more, but leave enough neck so that it can be tied properly.
- A sandy soil is most desirable for filling sandbags but any other available material such as silt, clay, gravels or a mixture of these may be used. Sand is a pervious material and additional weight is obtained when the soil in the sack gets saturated, and sand filled sacks shape really well. Clay materials are difficult to fill bags with and are difficult to shape. Gravels are too pervious and are very difficult to shape. In emergencies, when vehicle access is cut off, use the back side of the levee or adjacent dry field to obtain the sandbag material. Sandbag levees can be constructed by two people. Teams are better. A filled sandbag weighs 40-50 pounds.
- Sandbag filling operations can be accomplished at or near the placement site, or at centrally located filling sites such as fire stations, or other public works, or at sand borrow pits. If the bags are to be prefilled at a distant location, due consideration must be given to transportation vehicles and placement site access. In many cases, access may be only by boat, tractor or helicopter.
Sandbag Placement: General Guidelines
- Remove any debris from areas where bags are to be placed.
- Place bags lengthwise and parallel to the direction of flow with the untied open ends of the bags facing upstream.
- Fill low spots first before placing bags the full length of the area to be raised.
- Start at the downstream end of the sandbag operation about one foot landward from the river or levee's edge and continue upstream.
- Fold the open end of the bag under the filled portion. Place succeeding bags with the bottom of the bag tightly and partially overlapping the previous bag.
- Offset adjacent rows or layers by one-half bag length to avoid continuous joints.
- Compact and flatten the top of each bag by walking on it – continue this process as each layer is placed to eliminate voids, to prevent slippage between succeeding layers, and to form a tight seal.
Single Stack Placement
Sandbags stacked in a single row work well in areas where there is no streamflow velocity or danger from floating debris, such as logs and tree stumps, or from wave action which could topple the bags. Higher single stack placement can be effectively used as a barricade to protect structures from impending water damage. However, as a rule, do not stack sandbags above three courses or layers in height (approximately one foot).
Use pyramid placement to increase the height of sandbag protection but use caution when raising the levee height.
- Determine the height of the sandbag raise by using the best available forecasts of flood conditions. For example, if the water level is one foot below the top of the levee and is predicted to rise three more feet, construct a 2½-foot sandbag operation, including one-half foot of height as a safety factor.
- Compact each bag in place by walking on it, butting the ends of the sacks together, maintaining a staggered joint placement, and folding under all loose ends.
- Watch for flooding elsewhere and watch for boils on the landward side of the levee due to increased water elevation.
Ringing Sand Boil Placement
A “sand boil” is created by water seepage through the levee foundation or embankment. When seepage transports dirty water, the levee's integrity is threatened. It is generally not necessary to build a ring dike around a boil that is not transporting soils but monitor the boil for any change in condition.
- Do not attempt to place sandbags directly on the boil – pressure applied to plug the boil will cause water seeping through the levee to seek other avenues to follow and could cause levee failure.
- There should be a minimum of two- to three-foot radius from the center of the boil to the inside edge of the ring dike.
- Contain the entire area experiencing boils within the ring dike.
- Build a spillway section in the dike so water runs out in a controlled manner – this diverts overflow water away from the dike and reduces erosion on the levee slope.
- Once the spillway water runs clear and is not transporting soils, then the ring dike is completed.
Collection, Storage and Disposal
The New York State Department of Environmental Conservation encourages reuse of sand bags to the extent it can be reasonably accomplished given limitations of location, health of homeowners, availability of labor, etc.
- Sandbags that have not come into contact with contaminated floodwater can either be stored for reuse or debagged.
- Sandbags which have come into contact with floodwater and/or contaminated with raw sewage, industrial chemicals, petroleum products, etc. must be disposed of at a municipal solid waste landfill.
- Uncontaminated sand can be used as fill or aggregate in upland areas
ACCEPTABLE: Placement of uncontaminated sand on the lake shoreline.
PROHIBITED: Placement of uncontaminated sand in or alongside streams, tributaries, wetlands, or environmentally sensitive areas.