SURFACE WATER

Hydrosphere

Learning Targets

1. Compare streams and rivers and their importance

2. Describe what ponds and lakes are, and why they are important

3. Explain why wetlands are significant in the water cycle, and describe their biodiversity

4. Describe the causes of floods and their effects

Surface Freshwater

1. 3 categories: a) Moving waterb) Non-moving waterc) Wetlands

Moving water

1. Flows downhill, constantly movinga) Streams – moving water confined by

earthen banksb) Rivers – largest bodies of moving water

i. Amazon river moves 220,000 m3/sec

c) Source: where a stream beginsd) Mouth: where a stream ends

Non-moving Water

1.Ponds – small body of freshwater2.Lakes – larger body of freshwater

a) Most lakes are in the Northern Hemisphere

Glacier melt from the last ice ageCanada: 60% of worlds lakes

Parts of a lake

1. Littoral zonea) Along the shore

2. Photic zone (Limnetic)a) Sunlight reaches this area

3. Aphotic zone (profundal)a) Deep water; very little

photosynthesis

Wetlands

1. Wetland – land that holds a significant amount of water; can be fresh or saltwater

2. Types of Wetlandsa) Marsh – grasses; no treesb) Swamp – lush trees

Low oxygen conditions – organisms must be adapted

c) Estuary – place where river and ocean mix Brackish water

Wetlands Ecological Importance

1. Wetlands are very importanta) Unique ecosystems – fragile and

sensitive; many endangered species

2. Very high biodiversitya) 5% of U.S. land area/30% of U.S. Plant

species

3. Wetlands naturally purify watera) Trap and remove fertilizers and pollutants

Floods

1. Flood: overflow of water in one placea) All bodies of water flood; too much

precipitation to be absorbed

2. Lots of vegetation is the best way to limit flooding

a) Wetlands minimize flooding; act as buffer between water and land

3. Flooding moves and deposits nutrient rich sediments in floodplains

a) Erosion