The pyramid placement is used to increase the height of sandbag protection. Stamp each bag in place, overlap sacks, maintain staggered joint placement, and tuck in any loose ends. Free flowing water wants to move to lower elevations. If a levee is stopping floodwaters, the water may be able to find weak points to enter. If the water finds a large enough path, the flow will become visible, and is a serious threat to the integrity of the levee.
Most boils occur in sand, silt, or some combination.
A boil can be found only by close inspection. Another is obvious water movement in what appears to be standing water. Carefully examine the water for movement. If there is any movement in the water, carefully approach the site, disturbing the water as little as possible. Let the water settle, and look at the suspected site.