A sandbag barrier is an inexpensive, temporary barrier or wall, one to two feet high that is constructed by stacking sand-filled or earth-filled sandbags and placing them to divert mud and other debris flows away from buildings. However, these barriers do not provide protection from high debris flows.
When is a Sandbag Barrier Used?
These barriers are used to protect building sites vulnerable to low mud debris flows from steep, erodible slopes that are partially or completely void of vegetation due to wildfire burns. This is an inexpensive, temporary protection method that can be used by homeowners before predicted rainfall. Sandbags deteriorate when exposed to continued wetting and drying for several months. If the bags need to be used for more than a few months, cement can be mixed with the sand. The cement and sand mixture will harden when the bags dry.
How is a Sandbag Barrier Installed?
Fill sandbags half full using sand or local soil, fold the top of the sandbag down, and then place the bag on its folded top. Place each sandbag as shown, finishing each layer before starting the next. Limit placement to two layers unless they are stacked against a building or sandbags are pyramided. It is important to place the bags with the folded top in the upstream or uphill direction facing the flow of water to prevent them from opening when water runs by.