37-40 Watersheds & Earth's Atmosphere

APES 2024

Watershed

Watershed

All land in a given landscape that drains into a particular stream, river, lake, or wetland

Characteristics of watersheds

• Area

• Length

• Slope

• Vegetation types

• Divids with adjoining watersheds

Watersheds can be affected by

• Dams

• Floodplains

• Designing housing development along a river

Importance of watersheds

Analysis of upstream land and downstream water for quality indicators

Surface water and stormwater runoff will drain downstream

Water sheds

Area

Reflects the volume of water that can b egenerated from a rainfall

Length

Can be measured in different ways, generally considered the principle flow path

Slope

Will affect momentum of runoff, velocity, overland flow, watershed erosion potential, and local wind systems

Atmosphere

The thin layer of gases around Earth

What does the atmosphere do

• Provides oxygen

• Absorbs radiation

• Moderates climate

• Transports and recycles water & nutrients

Composition of the atmosphere

• 78% Nitrogen

• 21% Oxygen

• 9% Argon

• Trace amounts of other gases (carbon dioxide, ozone, nitrous oxide, and methane)