Chapter 13 Outline

Chapter 13 Outline - Chapter 13: Water Resources:...

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Chapter 13: Water Resources: Preserving Our Liquid Assets and Protecting Aquatic Ecosystems 13.1 The Hydrological Cycle Water is a renewable resource, purified and distributed in the hydrological cycle, which is driven by solar energy. Although the Earth is endowed with an enormous quantity of water, only a small fraction of the planet’s water is available for human use, a fact that underscores the importance of managing it wisely. 13.2 Water Issues Related to Supply and Demand Where Does Water Come From and Who Uses It? Globally, agriculture and industry are the major users of water. Most water comes from surface water supplies – rivers, streams, and lakes. Water Shortages Water shortages occur virtually everywhere. They are most prevalent in areas that receive small amounts of precipitation but can occur in any region in which demand exceeds existing water supplies. Population growth, agricultural expansion, and demand for water by industrial sector are likely to make water shortages even more prevalent in coming years. Drought and Water Shortages Droughts occur naturally, but may also result from human actions such as deforestation and overgrazing. Droughts reduce water supplies and create significant social, economic, and environmental problems. Impacts of the Water Supply System Water comes from an elaborate and costly system that has a tremendous impact on the environment. Understanding the system and its impacts may help us design more sustainable systems of water supply. Excessive withdrawal of surface water can cause streams to dry up, with profound effects on fish and wildlife. Groundwater overdraft results in many problems, too, among them depletion of water levels in connected surface waters and subsidence. Dams and reservoirs have many benefits, such as flood control and water storage, but they also have profound impacts on people, wildlife, and the economy. They can eliminate native fishes, block fish migration routes, flood wildlife habitat and farmland,
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This note was uploaded on 11/03/2009 for the course GEOS 105 taught by Professor Staff during the Spring '08 term at Texas A&M.

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Chapter 13 Outline - Chapter 13: Water Resources:...

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