Groundwater

Definition

Groundwater is the water that fills the cracks and spaces in underground soil and rock layers, making up a significant portion of the Earth's fresh water supply. It plays a crucial role in the water balance, as it interacts with surface water and is essential for various ecosystems, agriculture, and human consumption.

5 Must Know Facts For Your Next Test

1. Groundwater accounts for about 30% of the world's freshwater supply, making it a vital resource for drinking water and irrigation.
2. The movement of groundwater is influenced by the permeability of soil and rock layers, which affects how quickly or slowly water can flow through aquifers.
3. Groundwater can interact with surface water bodies like rivers and lakes, leading to exchanges that affect both ecosystems and water quality.
4. Over-extraction of groundwater can lead to issues such as land subsidence, reduced water quality, and depletion of aquifers.
5. Groundwater plays a critical role in maintaining base flow in rivers during dry periods, supporting aquatic life and ecosystem health.

Review Questions

• How does groundwater contribute to the global water balance and why is it essential for maintaining ecosystem health?
  • Groundwater contributes to the global water balance by acting as a reservoir that stores a significant amount of freshwater. It supports ecosystems by providing base flow to rivers and streams during dry periods, which helps maintain habitat conditions for aquatic species. Additionally, groundwater replenishes surface water bodies through interactions that help stabilize ecosystems and provide necessary resources for plants and animals.
• What are the primary processes involved in the hydrologic cycle that lead to groundwater recharge, and how do they impact groundwater availability?
  • The primary processes involved in groundwater recharge include precipitation infiltrating into the soil, percolation through unsaturated zones, and lateral movement from surface water bodies. These processes directly impact groundwater availability by determining how much water enters aquifers and how quickly it replenishes. Variations in rainfall patterns or land use changes can significantly influence these processes, affecting both quantity and quality of groundwater resources.
• Evaluate the consequences of groundwater-surface water interactions on both local ecosystems and human communities.
  • Groundwater-surface water interactions have profound consequences on local ecosystems by sustaining river flows during dry spells, which is crucial for maintaining biodiversity. For human communities, these interactions influence water availability for drinking, agriculture, and industry. Over-extraction or contamination of groundwater can disrupt these natural interactions, leading to reduced river flows, negative impacts on aquatic habitats, and challenges for communities reliant on these resources for their livelihoods.

Related terms

Aquifer: A geological formation that can store and transmit groundwater, serving as a crucial source of water for wells and springs.

Water table: The upper surface of groundwater, below which the soil or rock is saturated with water, indicating the level at which groundwater pressure is equal to atmospheric pressure.

Recharge: The process by which groundwater is replenished through precipitation, infiltration, and other means, ensuring sustainable groundwater levels.