SCIENCE 8 Unit 1- Water Systems on Earth Slideshow 1 Chapter 1 -The water cycle plays a vital role on Earth Section 1.3 – Sources of Fresh Water

1.3 Sources of Fresh Water Lakes, ponds and wetlands Streams and rivers Ground water Glaciers Drainage basins (c) McGraw Hill Ryerson 2007

Ground water is water that soaks into the ground Rock/ground with good porosity allows more water to enter More pores (spaces in the rock/soil), the better the porosity An aquifer is a layer of porous rock that allows ground water to flow, almost like a river below the surface. (c) McGraw Hill Ryerson 2007

Ground Water Humans get fresh water from Reservoirs, natural or man-made Wells, drilled into aquifers down to the water table (c) McGraw Hill Ryerson 2007

Q…Suggest some conditions which might increase run-off. Precipitation becomes run-off as gravity pulls water down into the groundwater, a lake or an ocean basin. Q…Suggest some conditions which might increase run-off. (c) McGraw Hill Ryerson 2007

Factors That Affect RunOff Type of Surface - Soil vs Rock Saturation of Ground – Saturated soil means more runoff Slope - The Steeper the slope the more run off Vegetation – Less Vegetation more runoff Human Development – ie more runoff on concrete or pavement. (c) McGraw Hill Ryerson 2007

Drainage Basins Drainage basins are large areas where surface water all moves towards one main river Run-off flows into streams and smaller rivers, which are tributaries of large rivers, forming a branching system See e 379 (c) McGraw Hill Ryerson 2007

There may be many small watersheds within a larger drainage basin. Drainage Basins Watershed The area of land that drains into a body of water such as a river, pond, lake or ocean. There may be many small watersheds within a larger drainage basin. (c) McGraw Hill Ryerson 2007

6 Major Drainage Basins in NL Labrador Sea Gulf of St. Lawrence West Coast Gulf of St. Lawrence South Coast Gulf of St. Lawrence Atlantic Ocean Avalon Peninsula Atlantic Ocean North-east Coast (c) McGraw Hill Ryerson 2007

Almost 66% of all fresh water on Earth is in glaciers (c) McGraw Hill Ryerson 2007

Alpine Glaciers (right) Found in mountain valleys Continental Glaciers of Antarctica (above) (c) McGraw Hill Ryerson 2007

Glaciers Glaciers slow down the passage of water through the water cycle by storing vast quantities of water. They release the water during the hot summer months. (c) McGraw Hill Ryerson 2007

Water trapped in glacial ice (c) McGraw Hill Ryerson 2007

Glaciers covered ~ 20% of land on Earth. The Ice Age The most recent began 120 000 years ago ending 11 000 years ago. Glaciers covered ~ 20% of land on Earth. (c) McGraw Hill Ryerson 2007

The Ice Age Why Do you think the coastline during the ice age differed from the modern coastline??? (c) McGraw Hill Ryerson 2007

Glaciers and Global Warming In the last 100 years the average temperature has increased dramatically. The world’s glaciers are melting at a quicker paces than ever before. (c) McGraw Hill Ryerson 2007

Melting Greenland Glacier (c) McGraw Hill Ryerson 2007

Receding Athabasca Glacier in Alberta It has receded Glaciers and Global Warming Receding Athabasca Glacier in Alberta It has receded 1.5 km since 1843. (c) McGraw Hill Ryerson 2007

Glaciers and Global Warming Q….Suggest Some implications of the glacier melting. (c) McGraw Hill Ryerson 2007

Salinity of Oceans may decrease Flood rivers What does this mean? Sea Level may rise Salinity of Oceans may decrease Flood rivers If glaciers disappear, rivers may dry up (c) McGraw Hill Ryerson 2007