Sources of Fresh Water Chapter 10.3

When it rains, water… a) Evaporates  makes precipitation b) Soaks into the ground  called groundwater c) Stays on the surface  called run-off

Run-Off Run-off = water that stays on Earth’s surface - Gravity pulls it downhill  stream or river  pond, lake or ocean

Run-off is important to think about It brings good & bad things to lakes, rivers, & oceans with the water Minerals Nutrients Pollution These things affect plant and animal life

Run-off is important to think about http://www.youtube.com/watch?v=GYMK9U57j0w&feature=related

Factors that affect Run-off 1. Type of ground material More run-off on rock than soil

2. Precipitation Length of time Amount

3. Slope of the land Steeper land  less water absorbed (more run-off)

4. Vegetation

E.g., Clearcuts

Development (roads, cities) Concrete doesn’t allow water to be absorbed into the ground http://www.youtube.com/watch?v=HcY8sfLDeYA&feature=related

Run-off Problems Flooding Soil carried away by run-off Pollution Soil & silt churned up  harmful to fish Let’s think about this stuff! Read p 376, 377, 378. Do the Activity on p 378. Make a drawing of the landscape, including the proposed development “What to Do” #1 “What Did You Find Out?” #1 & 2

Drainage Basins The area of land where precipitation falls and finds its way into a common river Small streams feed into bigger streams which feed into rivers which feed into the ocean

Ground Water Water that is stored in pores of rocks underground Aquifers are rocks Layers with good porosity Water Table Aquifer

Glaciers 2/3 of the world’s fresh water is trapped in glaciers

Large blocks of ice flowing downhill Compressed snow becomes ice

Two Types Alpine – mountain glaciers Continental – cover large areas of land: Antarctica and Greenland

Alpine glaciers move downhill until it is warm enough for them melt faster than gravity pulls it down Or Glaciers reach the ocean and break off to form icebergs Homework: Text p 385 1-10

Homework: P 385 1-10 (Textbook)