What could occur if excessive compaction happens during retention basin construction?

Excessive compaction during the construction of a retention basin can lead to soil degradation, which primarily refers to the reduction in soil quality and health. When soil is compacted too much, the spaces between the soil particles are minimized, resulting in decreased porosity and reduced infiltration capacity. This can hinder the soil’s ability to absorb and retain water, ultimately affecting the basin's function of managing stormwater.

Soil degradation can also lower the organic matter content and disrupt microbial activity, which are essential for maintaining a healthy soil ecosystem. A well-functioning retention basin relies on healthy soil to facilitate effective filtering of pollutants and the slow release of water, so any degradation impacts these processes adversely.

The other options do not accurately reflect the effects of excessive compaction. Enhanced filtration and improved water retention would not occur since compacted soil tends to impede both of these functions, while the option suggesting that none of the outcomes apply fails to account for the significant threats posed by excessive compaction.