What materials are typically used to construct artificial levees?

Artificial levees are primarily constructed from soil, sand, gravel, and similar materials because these substances are readily available and easily compacted to create barriers that can effectively direct and contain water flow. The use of these materials allows for flexibility in design and enables the levee to effectively withstand the hydraulic pressure exerted by the water.

Soil, in particular, is crucial as it can be manipulated to achieve various engineering properties such as compaction and moisture retention. Sand and gravel contribute to drainage capabilities while still being strong enough to hold back water. This combination supports the structural integrity of levees and ensures they function effectively in flood control.

The other options do not reflect typical construction methods for artificial levees. Concrete and bricks may be used in specific situations but are not the primary materials due to their cost and inflexibility. Natural soil and grass would not provide the necessary strength and structure needed for levee construction. Rock and metal alloys are also generally not utilized in levee construction because they are more suited to different types of infrastructure rather than earthen barrier systems.