Part 2 - Too Little Water VS To Much Water Water Resources Part 2 - Too Little Water VS To Much Water Remember: The stuff in yellow you do not have to write but that doesn’t mean it is not important. The stuff in yellow is probably on your outline 

Scarcity VS. Drought Water scarcity is caused by dry climate, dry soil, and too many people straining the water supply. (Water Scarcity is like the beginning stages of drought) Drought occurs when precipitation is at least 70% lower than usual and evaporation is higher than normal for more than 21 days.

What Is Desiccation? Desiccation occurs when the soil dries out because of the causes of drought and because of deforestation and overgrazing. THIS IS EXTREME DROUGHT.

Increasing numbers of people relying on limited runoff produces lower availability of water, which leads to water stress. Water stress in a region comes when reliable runoff availability drops to less than 60,000 cubic feet per year. Water scarcity occurs when water availability falls below 35,000 cubic feet per year. Almost 41% of the world’s population lives in river basins that suffer from either water stress or water scarcity. This figure could reach 40 countries by 2020 and 60 countries by 2050.

The volumes of water in some of the world’s largest lakes have shrunk by 85–92% since 1960 because of water diversion and periods of prolonged drought. A United Nations study found that one of six people do not have access to adequate, affordable, and clean water. Poor people live in hydrological poverty—they have no access and/or cannot afford clean water at a reasonable cost. Freshwater supply can be increased by building dams to store water for later use, importing water from elsewhere, using groundwater, and utilizing desalination processes.

STOP! Work on your HW! Water Resources Outline Due 2.9 Read Pages 289-303 in the BLUE BOOK by 2.9 Current Event 4 on Insects & Food Due 2.13

People in developed countries usually live near water supplies. Illegal in Florida People in developed countries usually live near water supplies. People in developing countries have to make do with what they have. (Some walk miles to get to a water source) Most people believe that everyone has a right to clean water. What do you think? Most water resources are owned by governments and managed as publicly owned resources, but a number of governments are hiring private companies to manage them.

Why would people live near floodplains? Flooding Flooding occurs when heavy rain or snowmelt cause streams & rivers to overflow onto land. Why would people live near floodplains?

Positives of living on Flood Plains: Fertile soil. A lot of water. Nearby rivers for transportation and recreation. Flat land for crops, buildings, highways, and railroads. Negatives: Floods kill thousands of people and destroy properties. Floods are usually considered natural disasters, but since the 1960s, humans have contributed to floods & flood destruction.

Flooding Continued… Fact: Paving and building on floodplains also increases the chance of severe floods. (water just flows on the pavement) Removal of water-absorbing vegetation contributes to greater flooding. (deforestation) Fact: Draining wetlands removes a needed “sponge” to absorb floodwaters and reduce the severity of floods. (this is bad) Great floods used to occur about every 50 years or so, but since the 1970s, they now occur about every 4 YEARS.

Case Study: Hurricane Katrina What Happened? Hurricane Katrina was a devastating natural disaster with far reaching effects. The Hurricane Breached over 23 drainage canals resulting in massive flooding. Over 80% of New Orleans was flooded and some parts of the city were under 15 feet of water. 1,464 people died. Over $150 BILLION in damage. WHY did this happen?

Case Study: Hurricane Katrina Extremely destructive storm, during a high tide, with a large storm surge (wall of water). New Orleans is below or at sea level in most areas of the city.

Solving Floods Levees or floodwalls can be built. This method contains/accelerates the stream flow but increases the possibility for damage downstream. (If not properly maintained, disaster can occur) Building dams can also reduce the threat of flooding by storing water in a reservoir for later slow release. (If not properly maintained, disaster can occur) Preserve existing wetlands and restore degraded wetlands to take advantage of natural flood control. Identify and manage flood-prone areas.

Dams & Reservoirs! The Good, The Bad, & The ugly 9/21/2018 8:01 PM Yellow = Do Not Write Down © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Dams! Dams and Reservoirs capture and store runoff water. There are an estimated 800,000 dams that restrict the flow of rivers worldwide.

The Good: The water is released to control floods, generate electricity, and irrigate lands. Reservoirs also provide for swimming, fishing, and boating. The Bad: Dam and reservoir construction displaces people and floods productive land behind the dam.

The Ugly: A series of dams on a river in an arid area can disrupt the hydrologic cycle, since the water may not reach the sea that it previously supplied with water. *Colorado River* The Really Ugly: About 60% of the world’s major river basins are strongly or moderately fragmented and disturbed.

The Colorado River is 1,400 miles long and has been altered by 14 major dams and reservoirs to the point that water rarely reaches the Gulf of California now. This endangers many species that spawn in the river system and has led to increased salt contamination of aquifers near the coast.

The Good: The dams and reservoirs make it possible to grow crops, have recreation, raise livestock, generate electric power, and increase the population of rather arid areas. The Bad: The pacts that were drawn for water allocations to the U.S. and Mexico did not consider environmental needs; no allocations were made for the environment. The Ugly: Water was supplied to farmers and ranchers at a low price. This has led to inefficient use of this water, including growing high water demand crops such as cotton, rice, and alfalfa. Other problems include evaporation, leakage, and siltation from large reservoirs.

1.4 miles long and 600 feet tall! Case Study: The Three Gorges Dam on the Yangtze River (in China) is the largest hydroelectric dam and reservoir in the world. The Bad: 1.3 million farming people were relocated on some land that will not grow much food. 1.4 miles long and 600 feet tall!

The Good: The dam will reduce China’s dependence on coal and hold back the Yangtze’s floodwaters. Large cargo-carrying ships will be able to go into China’s interior and thus reduce current transportation costs. The Ridiculously Bad: The dam is built over a seismic fault, and there is worry that millions of people will be killed should the dam collapse.