When constructing an evaporation/absorption lagoon, how deep should the berm walls be keyed into the original soil?

The correct depth for keying the berm walls of an evaporation/absorption lagoon is essential for ensuring stability and preventing erosion or failure of the structure. Keying the berm walls into the original soil helps create a solid foundation that can withstand water pressure and retention without collapsing or leaching contaminants into the surrounding environment.

Keying the walls at a depth of 1 foot allows for adequate support while also making construction practical and cost-effective. Additionally, a width of 2 feet at the base provides enough surface area for the berm to distribute the load evenly and to enhance the overall stability of the structure. This balance ensures that the berm can effectively manage the water that will be stored and evaporated in the lagoon, while also preventing failures that could result from too shallow or insufficiently supported berm designs.

Selecting a depth deeper than 1 foot, such as 2 feet, might be excessive for the design requirements, leading to unnecessary excavation and increased project costs, while shallower depths could compromise the integrity of the berm. Therefore, a 1-foot depth combined with a 2-foot width is an optimal choice for the structural needs of the lagoon.