How does desertification reduce supplies of drinking water?

Desertification reduces the availability of potable water primarily by diminishing surface water and groundwater flow. This process is driven by several ecological and human-induced factors:1

• Reduced Recharge: Desertification often involves the loss of vegetation and the degradation of soil structure. Because healthy soil and plant cover are essential for facilitating the drainage that replenishes aquifers, their loss hinders the natural process of groundwater recharge.123
• Increased Sedimentation: As land becomes degraded, erosion increases. Rising sedimentation in rivers and lakes can disrupt water flow and quality, further limiting the supply of usable water.1
• Soil Compaction and Runoff: Activities such as overgrazing can compact the soil and destroy plant roots that bind the earth. This prevents water from infiltrating the ground, leading to increased surface runoff rather than the absorption necessary to maintain water tables.4
• Pollution: The degradation of these environments often leads to increased water pollution from dust and sediment, which further compromises the safety and availability of existing water stocks.1