What preparation must occur prior to fill being placed?

The appropriate preparation prior to placing fill involves the removal of topsoil and organic material. This step is crucial because topsoil and organic matter can lead to settlement issues and instability within the fill once it is placed and compacted. The existing organic materials can decompose, leading to voids and reduced support for structures built on top of the fill. Therefore, clearing away these materials ensures a more stable and uniform subgrade is established for the fill placement. By preparing the site in this manner, the chance of improper compaction and future differential settlement is significantly reduced, leading to enhanced structural integrity.

In contrast, while watering existing soil may serve a purpose in other contexts, it does not directly address the necessity of a stable foundation for the fill. Soil compaction before filling is generally not standard practice, as the fill itself should ideally be compacted once placed. Lastly, beginning filling immediately without any preparation compromises the integrity of the fill placement and can lead to performance issues later on.