Geography: Topography and Land Use

Slope/Gradient/Topography

• Steepness of the land surface affects discharge and watershed, with increased slope resulting in higher potential energy and erosive power of water.
• Steep slopes have a high degree of runoff and are more susceptible to erosion.

Land Use/Land Cover

• Vegetative cover helps control runoff and erosion by:
  • Reducing raindrop impact on the soil surface
  • Reducing water flow velocity
  • Allowing for greater infiltration of water into the soil
• Impervious surfaces (e.g., streets, parking lots, rooftops) increase runoff and erosion by:
  • Reducing water absorption
  • Increasing water flow to waterways
  • Causing stream bank erosion, sedimentation, and flooding
• Natural features like wetlands, uncompact soils, and vegetation absorb water runoff and reduce erosion.

Human Impact on Watersheds

• Industrial and agricultural activities can alter watersheds through:
  • Point sources of pollution (e.g., pipes discharging pollutants from industrial plants or sewage treatment facilities)
  • Nonpoint sources of pollution
• Human activities affect watershed productivity, including:
  • Hydrological cycle
  • Water provision for urban, agricultural, and environmental needs
  • Sociopolitical-ecological entity ensuring food, social, and economic security

Importance of Watersheds

• Watersheds provide life support services to rural people, including:
  • Water provision
  • Food security
  • Social and economic security