What influences surface runoff on a site?

Surface runoff is influenced by several environmental and physical factors that determine how water moves across a landscape after precipitation events. The first key aspect is soil type; different soils have varying capacities for infiltration and retention. Sandy soils, for example, drain quickly and may contribute to higher runoff, while clay soils tend to retain water longer, reducing runoff.

Vegetation plays a crucial role as well. Plants absorb water through their roots and can slow down the movement of water across the surface. Dense vegetation can help intercept rainfall, allowing for more water infiltration and reduced runoff.

Precipitation is another significant factor. The intensity and duration of rainfall impact how much water saturates the ground versus flowing over the surface. Heavy rainfall may lead to increased runoff, especially if the soil is already saturated.

Slope affects both the speed at which water will flow and how much water is actually absorbed into the ground. Steeper slopes typically result in faster runoff rates due to gravity pulling water downward, which also reduces the chances for infiltration.

In contrast, building design and layout, landscape aesthetics, and friction from built surfaces might have indirect effects on runoff but are not the primary factors influencing surface runoff in the way soil, vegetation, precipitation, and slope do. Hence, these aspects do not directly