What role do soils play in stormwater management?

Soils play a critical role in stormwater management primarily through their ability to absorb and filter runoff. When rainwater falls on impermeable surfaces such as asphalt or concrete, it can lead to an increase in surface runoff, which can wash pollutants into local waterways. However, when that rainwater comes into contact with soil, the soil acts as a natural filter. It absorbs the water, allowing it to percolate through the soil layers. This process not only helps in reducing the volume of runoff but also aids in filtering out sediments and pollutants, improving water quality before the water recharges groundwater supplies or flows into streams and rivers.

Furthermore, different types of soils have varying capacities for absorption and filtration. For instance, sandy soils typically drain quickly, while clay soils may have slower absorption rates but can still retain water effectively. This inherent ability of soils to manage stormwater is vital for preventing flooding, managing water quality, and sustaining local ecosystems.