When a flood’s about to arrive, so are the sandbags. Over the years, sandbags have been made from a variety of materials, including burlap and polypropylene as well as a few others. Once manufactured, the bags are filled with sand or soil, and placed strategically about a city to prevent more flooding where possible. Volunteers are instructed to build “dikes” or “levees,” and often times, these piles of sandbags will be seen near rivers and bridges for added, and necessary, flood prevention.

Sandbags have been used since the 18th century, when they were traditionally used for military purposes. First more commonly made of burlap, times have progressed and sandbags are now popularly made from polypropylene plastic, and are sent to flood-endangered areas by the thousands. With its history of devastating floods, Iowa and other Midwestern states have many businesses and organizations that volunteer to send sandbags to the affected areas, and citizens band together to fill the bags before the floods hit.

Sandbags have continued to retain their popularity thanks to three main advantages. When preparing for a flood, bags and the sand to fill them are considerably inexpensive, and can easily be brought empty to the site and then filled with sand upon arrival. After the flood has passed, sandbags are easily transported and stored once emptied, though there has been a voiced concern about the possible contamination of the sand from floodwater. In constructing and deconstructing sandbag efforts, it’s of utmost importance that volunteers follow directions, like those in the video we’ve posted below, for the safest and most effective levees and dikes.