Water+Resources

Chapter Overview

  • Title: Water Resources

  • Author: Dr. Christy Jean

The Hydrosphere

  • Definition: One of Earth's four spheres; includes all water on the planet.

  • Water Coverage: 2/3 of the planet's surface is water.

  • Types of Water: 97.2% is saltwater; 2.8% is freshwater, mostly locked in ice or difficult to access.

Hydrologic Cycle

  • Processes: Movement of water through evaporation, condensation, precipitation, infiltration, and runoff.

  • Pools: Storage locations for water such as oceans, lakes, rivers.

  • Fluxes: Various movements of water between these poolsi.e., evaporation and precipitation.

Freshwater Distribution

  • Freshwater Availability: Less than 1% of Earth's freshwater is available for human use.

  • Sources: Lakes, reservoirs, groundwater, and streams.

  • Major Lakes: Lake Superior - largest by surface area; Lake Baikal - largest by volume.

Evaporation and Precipitation

  • Evaporation: Water turns from liquid to vapor from various sources.

    • Transpiration: Evaporation from plant surfaces.

    • Evapotranspiration: Combined total of evaporation and transpiration.

  • Condensation: Water vapor changes to liquid in the atmosphere, leading to precipitation (rain, snow).

Groundwater

  • Infiltration: Process of water entering the ground and moving into aquifers.

  • Aquifers: Underground layers of permeable rock storing groundwater.

  • Saturation: Zone where all voids in soil or rock are filled with water.

Lakes and Wetlands

  • Types of Wetlands: Swamps (tree-dominated), marshes (grass-dominated), and constructed wetlands (for treatment purposes).

  • Importance: Wetlands filter runoff, provide habitats, & regulate water cycles.

Environmental Concerns

  • Thawing Permafrost: Rapid thawing due to climate change may release pollutants like mercury.

  • Water Pollution: Sources include industrial waste, agricultural runoff, and fracking.

Human Impact on Water Resources

  • Water Withdrawals: Sourced from agriculture, industry, and municipal use.

  • Groundwater Depletion: Excessive pumping leads to subsidence and diminished water supply.