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Lecture Environmental science - Chapter 7: Water

After completing this unit, you should be able to: Distinguish the three soil textures; define the relationship between the textures and aeration, workability and water holding capacity; what are ways of desalinating water? What are the disadvantages of this process? Why do different regions of the world receive different amounts of precipitation? Describe how water demands might be reduced in agriculture, industry, and households. | Chapter 7: Water Figure 7-1 Earth’s water supply Problem: Fresh water availability Key Facts The primary use for fresh water in U.S. is for agriculture. In our homes, we use the most fresh water to wash, clean, and flush. The typical person in an industrialized nation uses 700-1000 gallons per week! Figure 7-4 Condensation (The amount of water in the air) Human effects on the Hydrologic Cycle Figure 7-3 The Hydrologic cycle Figure 7-6a Global air circulation Figure 7-6b Global air flow patterns Rain shadow Figure 7-7 Rain shadow The Ogallala Aquifer Figure 7-16 Exploitation of an aquifer Reasonable access to safe drinking water is defined as the availability of at least 20 liters per person per day from an improved source within 1 kilometer of the user's dwelling. Percentage of Population Without Reasonable Access to Safe Drinking Water 2008 http://www.theglobaleducationproject.org/earth/human-conditions.php Population with access to safe water, 1990 pg. 213 Saltwater Intrusion Figure 7-18 Saltwater Intrusion Mono Lake Excellent example of human interference with the water supply. The water in the lake was diverted from the lake to the city of Los Angeles. It became a salt bed. ↑ Salt concentration due to evaporation Agriculture Green Revolution- the introduction of high-yield grains to agriculture. High yield varieties are not ideal for subsistence farming because they need pesticides and chemical fertilizers. Sustainable- Crop rotation, variety of crops, animal wastes for fertilizer. The best, most effective way to solve world hunger is to help people provide for themselves. Water Quality tests Nitrates pH Phosphates What do they tell you about your water? Figure 7-6c Global trade winds Figure 7-5 Global Precipitation Figure 7-5 Global precipitation | Chapter 7: Water Figure 7-1 Earth’s water supply Problem: Fresh water availability Key Facts The primary use for fresh water in U.S. is for agriculture. In our homes, we use the most fresh water to wash, clean, and flush. The typical person in an industrialized nation uses 700-1000 gallons per week! Figure 7-4 Condensation (The amount of water in the air) Human effects on the Hydrologic Cycle Figure 7-3 The Hydrologic cycle Figure 7-6a Global air circulation Figure 7-6b Global air flow patterns Rain shadow Figure 7-7 Rain shadow The Ogallala Aquifer Figure 7-16 Exploitation of an aquifer Reasonable access to safe drinking water is defined as the availability of at least 20 liters per person per day from an improved source within 1 kilometer of the user's dwelling. Percentage of Population Without Reasonable Access to Safe Drinking Water 2008 http://www.theglobaleducationproject.org/earth/human-conditions.php Population with access to safe water, 1990 pg. 213 Saltwater .