Watersheds and Their Importance

Definition of a Watershed

• A watershed is a land area where all water drains into a central body, like a river, lake, or stream.
• Determined by the slope of the land, acting like a funnel directing water due to gravity.
• Boundaries decided by slope: Water on one side flows to one watershed, on the other side to another.

Factors Influencing Watersheds

• Vegetation: More vegetation increases infiltration, slowing water, and aiding soil permeability.
• Slope: Greater slope increases runoff velocity, causing more soil and debris movement.
• Soil Permeability: Determines whether water runs off or infiltrates and recharges groundwater.
• Human Activities: Actions like mining and agriculture introduce pollutants; affect water quality.

Chesapeake Bay Watershed

Overview

• One of the largest watersheds in America, covering six states.
• Rivers and streams drain into Chesapeake Bay.

Ecological and Economic Importance

• Estuary Habitat: A mix of salt and fresh water, rich in nutrients and sediments.
• Ecosystem Services:
  • Tourism: Economic benefits from activities like kayaking, canoeing.
  • Water Filtration: Natural pollutant filtration by estuaries and wetlands.
  • Habitats: Support for species like crabs and shellfish; crucial for seafood industry.
  • Storm Water Protection: Acts as overflow or surge protection during storms.

Human Impacts on Chesapeake Bay

Nutrient Pollution

• Excess nitrogen and phosphorus lead to eutrophication (algae blooms).
• Blocks sunlight, causing plant death; bacteria consume oxygen, leading to hypoxia (low oxygen levels).

Sources of Nutrient Inputs

• Wastewater treatment discharge, especially during overflows.
• Runoff from agriculture, including synthetic fertilizers and CAFOs manure.

Other Pollutants

• Endocrine Disruptors: Medications not fully removed by treatment plants.
• Sediment Pollution: Resulting from clear-cutting, urbanization, farming.
  • Covers stream bottoms, affecting aquatic life; decreases photosynthesis, increases water temperature.

Solutions to Water Pollutants

Agricultural Practices

• Cover Crops: Prevent soil erosion and nutrient runoff.
• Manure Management: Improved lagoons, frequent draining, converting to fertilizer.

Riparian Buffers

• Vegetation along water bodies acts as a filter and sponge to reduce pollutants.

Human Waste Management

• Septic Tank Upgrades: Optimizing drain fields to filter more effectively.
• Biological Waste Removal: Microbes consume waste nutrients, reducing river nutrient release.