Groundwater recharge is the process through which water moves downward from surface water to underground aquifers. Soil type and its permeability play a crucial role in determining the rate of groundwater recharge. These factors influence how easily water can infiltrate the ground and reach the water table.
1. Soil Type and Texture
Different soil types have different particle sizes and structures, which affect water infiltration:
- Sandy Soils
- Contain large, coarse particles.
- Have high porosity and very high permeability.
- Water can easily pass through, resulting in rapid groundwater recharge.
- Clayey Soils
- Contain very fine particles.
- Have low permeability due to tightly packed particles.
- Water movement is slow, leading to poor infiltration and low recharge.
- Loamy Soils
- A balanced mixture of sand, silt, and clay.
- Moderate permeability, allowing good infiltration with some water retention.
- Suitable for moderate groundwater recharge.
2. Permeability of Soil
Permeability is the ability of soil to transmit water:
- High Permeability
- Found in well-structured sandy or gravelly soils.
- Promotes quick and efficient groundwater recharge.
- Low Permeability
- Found in compacted or clayey soils.
- Causes surface runoff, reducing recharge rates.
3. Impact of Compacted or Impervious Layers
- Human activities like construction, heavy machinery, or paving can compact the soil.
- This reduces porosity and prevents water infiltration.
- Similarly, impervious layers (e.g., laterite, rock, or concrete) block water movement and hinder groundwater recharge.