Which of the following does not help in preventing soil erosion at a construction site?

Excessive excavation is a practice that can significantly contribute to soil erosion at a construction site rather than prevent it. When too much soil is removed from an area, the natural vegetation that holds the soil in place is disturbed, which can lead to increased vulnerability of the soil to wind and water erosion. The lack of ground cover and the exposed soil surfaces make erosion more likely, particularly during rainfall or heavy winds.

In contrast, the other options listed—vegetative cover, proper drainage systems, and retention basins—all play a role in reducing soil erosion. Vegetative cover protects the soil by absorbing rainfall and reducing the force of raindrops on the soil surface, while proper drainage systems help manage water flow and prevent pooling that could lead to erosion. Retention basins are designed to slow down runoff and provide a place for water to collect, thereby minimizing erosion potential.