Chapter 15 (science).pptx

Because learning changes everything. ENVIRONMENTAL SCIENCE A Study of Interrelationships, 16th Edition Chapter 15 Water Management Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. ® 15.1 The Global Water Chal...

Because learning changes everything. ENVIRONMENTAL SCIENCE A Study of Interrelationships, 16th Edition Chapter 15 Water Management Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. ® 15.1 The Global Water Challenge Global freshwater resources are threatened by rising demands. Growing populations need ever more water for drinking, hygiene, sanitation, food production, and industry. Climate change is expected to contribute to more droughts. Policy makers must figure out how to supply water without degrading the natural ecosystems that provide it. © McGraw Hill 2 15.2 The Water Issue 1 Water is the material that makes life possible on Earth. Water has remarkable physical properties: Water molecules are polar: one part of the molecule is slightly positive, and the other is slightly negative. Molecules tend to stick together. They also can separate other molecules from each other (solvent). Store Heat. Water quality is as important as its quantity. Potable water is unpolluted fresh water, suitable for drinking. Shortages can be directly attributed to human-induced water pollution. © McGraw Hill 3 Science behind water Water is a simple molecule consisting of one oxygen atom bonded to two different hydrogen atoms. Because of the higher electronegativity of the oxygen atom, the bonds are polar covalent (polar bonds). The oxygen atom acquires a partial negative charge, while the hydrogen atom acquires a partial positive charge. Water can change from a liquid to a solid or a gas and back to a liquid, but its molecules always stay the same. © McGraw Hill 4 Fun Fact When astronauts first ventured to the Moon in the late 1960s, they were captivated by a vision of the Earth in colour as it had never been seen before. It is not surprising that, after pictures like this were published, the Earth became known as the 'blue planet'. © McGraw Hill 5 15.2 The Water Issue 3 The World Health Organization estimates 10% of the world’s population does not have access to safe drinking water. According to the U.N. Environment Program, between 5 and 10 million deaths occur each year from water-related diseases, including cholera, malaria, dengue fever, and dysentery. These illnesses have been increasing over the past decade and without economic investments in safe drinking water supplies, the rate of increase will continue. © McGraw Hill 6 70% of Earth’s surface is covered by water in the form of oceans, representing 97% of all the Earth’s water. Of Earth’s freshwater (3% of total), only a tiny fraction is available for use. Estimated volume of water stored in earth: © McGraw Hill 7 Areas of the World Experiencing Water Stress Source: United Nations World Water Development Report 2015. Access the text alternative for slide images. © McGraw Hill 8 Water cycle or The Hydrologic Cycle Evaporation Transpiration Condensation Precipitation Runoff Evapotranspiration is the process of plants giving off water. Runoff is surface water that moves across the surface of the land and enters streams and rivers. Groundwater is water that fills spaces in the substrate. © McGraw Hill 9 15.3 The Hydrologic Cycle 4 Water entering the soil is either taken up by plant roots or moves downward until it reaches an impervious layer of rock, and accumulates in porous strata called an aquifer. An aquifer is an underground layer of gravel, sand, or permeable rock that holds groundwater that can be extracted by wells. An unconfined aquifer is usually near land’s surface. The top layer saturated with water is the water table. The lower boundary is impermeable layer of clay or rock. Vadose zone (zone of aeration) is the area above the water table unsaturated with water. The water in these aquifers is at atmospheric pressure and is recharged by rainfall and percolation. A confined aquifer is bounded on top and bottom by layers impermeable to water. Water in these aquifers is stored under high pressure and recharged by rain and surface water from a geologic recharge zone. An impervious confining layer is called an aquiclude. A permeable confining layer is called an aquitard. Porosity is a measure of the size and number of spaces in the substrate. © McGraw Hill 10 Aquifers and Groundwater Access the text alternative for slide images. © McGraw Hill 11 15.4 Human Influences on the Hydrologic Cycle A major concern in many urban areas is transportation of storm water. If trends continue 1.8 billion people will have a water scarcity by 2025, and 2/3 of the world’s populations could suffer water stress. Water must be treated before release A 2011 study found more than 200 unregulated chemicals, such as industrial solvents, weed killers, refrigerants, and rocket fuel component percholate in the drinking water of 45 states. Public attitude is a major cause of water loss. As long as water is a considered limitless, inexpensive resource, few conservation measures will be taken. © McGraw Hill 12 Urban Domestic Water Uses Shortages of water and increasing purification costs have raised the price of domestic water in many parts of the world, and increased costs do tend to reduce use. Many cities in China are setting quotas on water use that are enforced by higher prices for larger users. At the federal level, the U.S. Environmental Protection Agency (E P A) is in the process of developing a national consumer labeling program of water-efficient products modeled after its highly successful Energy STAR program. Leaking water pipes and mains account for significant losses of water. Even in the developed world, losses may be as high as 20%. Poorer countries may lose over 50% of water to leaks. Access the text alternative for slide images. © McGraw Hill 13 World Uses of Water Source: Data from World Resources Institute, 2012. Access the text alternative for slide images. © McGraw Hill 14 Agricultural Use of Water 2 There are four common irrigation methods: Surface / Flood: Requires extensive canal systems. Spray: Requires the use of pumps. Trickle: Strategically placed openings deliver water directly to the roots of plants. Sub-Irrigation: Underground pipes supply water to plants and can be used for drainage as well. © McGraw Hill 15 1 6 Types of Irrigation © McGraw Hill 16 Typical sprinkler (spray) irrigation Flood  © McGraw Hill Sub-Irrigation 17 Industrial Use Of Water 1 Industrial water use accounts for nearly 50% of all water withdrawal in U.S., 75% in Canada, and 23% worldwide. 90% of water used by industry is for cooling, and is returned to the source. Water is also used to dissipate and transport waste, resulting in stream and lake degradation. The Clean Water Act (1972) seeks to protect U.S. waters from pollution. Setting water quality standards for surface water. Limiting effluent discharges into the water. © McGraw Hill 18 In-Stream Use of Water 1 In-stream water use makes use of water in its channels and basins. In-stream uses are non-consumptive. Major in-stream uses are hydroelectric power, recreation, and navigation. Presently, hydroelectric power plants produce 6% of all electricity generated in U.S. Although hydroelectric dams control flooding and create electricity, they have drawbacks. Dams Interrupt the Flow of Water © McGraw Hill ©Stan Usinowicz/AP Photo 19 Effect of Organic Wastes on Dissolved Oxygen Dissolved organic matter is a significant water pollution problem because it decays in the water. Biochemical oxygen demand (BOD) is the amount of oxygen required to decay a certain amount of organic matter. If too much organic matter is added, all available oxygen will be used up. Disease-causing organisms are a very important pollution problem in most of the world. In the developed world, sewage treatment and drinkingwater treatment plants greatly reduce this public health problem. Nutrients can also be a pollution problem. Eutrophication is excessive growth of algae and aquatic plants due to added nutrients. Particulate matter can also affect quality. Access the text alternative for slide images. © McGraw Hill 20 15.6 Kinds and Sources of Water Pollution 4 A point source is a source of pollution readily located and identified. © McGraw Hill Nonpoint sources are more difficult to identify and control. 21 15.6 Kinds and Sources of Water Pollution 5 Individuals can protect surface and ground waters from nonpoint pollution: Use less toxic or nontoxic alternatives to commonly used home chemicals. Buy chemicals only in the amount you intend to use, and apply them only as directed. More is not better. Take unwanted household chemicals to hazardous waste collection centers. Do not pour them down the drain. Never pour unwanted chemicals on the ground. Use water-based products whenever possible. When landscaping your yard, select native plants that have low requirements for water, fertilizers, and pesticides. Test your soil before applying fertilizers. © McGraw Hill 22 Municipal Water Pollution 1 Waste from homes consists primarily of organic matter from garbage, food preparation, cleaning of clothes and dishes, and human waste. Fecal coliform bacteria is a generic term for bacteria found in the intestines of warm-blooded animals, such as Escherichia coli and Streptococcus faecalis. Numbers and types of bacteria present in water are directly related to amount of fecal matter entering the system. By January 2011, over 2000 Haitians died from a cholera outbreak due to contaminated drinking water. © McGraw Hill 23 Municipal, Industrial and Agricultural Water Pollution 2 Wastewater from cleaning dishes and clothing contains some organic material along with soap or detergent. Detergents contained phosphates, which contributed to eutrophication. eliminated from most major detergents since 19 94. Pharmaceuticals, hormones, detergent metabolites, insecticides, fire retardants, and plasticizers, among other chemicals, also found in municipal water discharge. Agricultural activities are the primary cause of water pollution. Excessive fertilizer use may lead to eutrophication in many aquatic habitats. Agricultural runoff from large, open expanses is a major source of water pollution Factories and industrial complexes frequently dispose of waste in municipal sewage systems. Mining is a special source of industrial water pollution. © McGraw Hill 24 Thermal Pollution 1 Thermal pollution occurs when industry withdraws water from a source, uses it for cooling purposes, and returns heated water to its original source. Today in the industrialized world, most cooling water is not released in such a way that aquatic ecosystems are endangered. methods of discharging heated water include: Large, shallow cooling ponds Cooling towers Dry Towers © McGraw Hill 25 Marine Oil Pollution 1 Marine pollution has many sources, including accidents such as the Deep Water Horizon spill in 2010. The Exxon Valdez ran aground in Prince William Sound, Alaska, in 1989 and spilled 42 million liters (11 million gallons) of oil. © McGraw Hill 26 Sources of Groundwater Contamination Access the text alternative for slide images. © McGraw Hill 27 15.7 Water-Use Planning Issues 1 Historically, wastes were discharged into waterways with little regard for costs imposed on other users by the resulting decrease in water quality. The population has grown dramatically, and thus domestic water use has intensified. There has not been enough water to satisfy everyone’s needs. Metropolitan areas must deal with and provide three basic services: Water supply for human and industrial needs. Wastewater collection and treatment. Storm water collection and management. © McGraw Hill 28 15.7 Water-Use Planning Issues 4 Future issues will have to be addressed: Increased demand will generate pressure to divert water to high-use areas. There will be increased demand for wastewater treatment and reuse of existing water supplies. Salt buildup due to evaporation may lower water quality. Groundwater over-pumping will cause water tables to be lowered. Seawater intrusion in coastal aquifers will ruin water supplies. There will be increased demand for water-based recreation, which demands high water quality. © McGraw Hill 29 Water Diversion Water diversion is the process of transferring water from one area to another. It is seen as a necessity in many parts of the world. One major consequence of diverting water for irrigation and other purposes is water bodies downstream are deprived of their source of water. This often has serious ecological effects. Lake levels decline, affecting fish and other wildlife populations. © McGraw Hill 30 © McGraw Hill 31 Wastewater Treatment 1 Primary sewage treatment removes large particles via filtration and then pumps remaining water into settling ponds and lakes. Secondary sewage treatment is a biological process that usually follows primary treatment. In a trickling filtering system, wastewater is sprayed over a surface of rock or other substrate to increase the amount of dissolved oxygen. Sewage sludge is a mixture of organisms and other particulate matter that have settled out during the treatment process. Activated-sludge sewage treatment plants hold wastewater in settling tanks with air continuously bubbled through it, and water and sludge eventually separate out. cis an additional stage used to remove inorganic nutrients such as phosphorous and nitrogen left after primary and secondary treatments. This process is extremely costly because it requires specific chemical treatment of the water. © McGraw Hill 32 Primary and Secondary Wastewater Treatment © McGraw Hill (a): ©Ray Pfortner/Photolibrary/Getty Images; (b): ©Jonathan A. Meyers/Science Source 33 Salinization 1 Salinization is an increase in salinity caused by growing salt concentrations in soil. As plants extract water from the ground, the salts present in all natural waters become concentrated.. © McGraw Hill 34 Groundwater Mining 1 Groundwater mining is removing water from an aquifer faster than it can be replenished. Extended periods of mining can lead to: Land settling. Lowering of the water table. Saltwater intrusion into wells near coastal areas. © McGraw Hill 35 Groundwater Mining 4 Groundwater sustainability is a tradeoff between groundwater use and the long-term effects of that use. Management strategies include: Shift from groundwater to surface water, import water from outside the local water-system boundaries. Control pumping with guidelines, policies, taxes, or regulations. Conservation practices, techniques, and technologies. Reuse wastewater (grey water) and treated wastewater (reclaimed water) for non-potable purposes. Desalination of brackish groundwater. © McGraw Hill 36 Preserving Scenic Water Areas and Wildlife Habitats Some bodies of water have unique scenic value. All federal agencies must consider the wild, scenic, or recreational values of certain rivers when planning and for the use and development of rivers and adjacent land. Historically, poorly drained areas were considered worthless, and were filled or drained and used as building sites. Only recently has the natural and economic importance of wetlands been recognized. © McGraw Hill 37 The Value of Wetlands ©Eldon Enger Access the text alternative for slide images. © McGraw Hill 38 UAE in Action for Wetlands The UAE became a member of the Ramsar Convention in 2007 and since then has pioneered wetland preservation. The Ras Al Khor Wildlife Sanctuary became the first UAE wetland listed by Ramsar as a site of international importance in 2007. Wadi Wurayah National Park (Fujairah), Al Wathba Wetland Reserve (Abu Dhabi) and the Mangrove Protected Area in Khor Kalba (Sharjah) were later added. The other sites in the UAE are Bul Syayeef Marine Sanctuary (Abu Dhabi), Sir Bu Nair Island (Sharjah) and Al Zorah (Ajman). © McGraw Hill 39 Water in UAE In addition to the available conventional water sources , the UAE started using desalinated water and treated wastewater since 1970s, in order to meet the growing water needs , as a result of unprecedented urban development, population growth and rising standards of living. © McGraw Hill 40 The unbalance between limited available water resources and high groundwater exploitation has caused decline in groundwater levels , increase of salt-water intrusion problems and total drought of many wells. Geographic location and prevailing climate are the main reasons for the absence of surface water sources such as rivers and lakes. © McGraw Hill 41 Water Stress The UAE is a water stressed country where the natural water supply is well below the water demand. In order to close the gap between supply and demand, several options for using nonconventional water resources were adopted, among those, is the desalination of sea water and brackish groundwater. The second option is reuse of treated sewage water as a second nonconventional water source. © McGraw Hill 42 © McGraw Hill 43 Strategies In 2010, the UAE Cabinet has approved the National Strategy for Preservation of Water Resources. This strategy adopts policies for water use , conservation and protection in all sectors. The integrated water resources management aims at managing water demand rather than maximizing and provision of water supplies. It also targets increasing rates of natural recharge of groundwater resources through the establishment and management of dams and breakers to raise the recharge rates of groundwater resources. © McGraw Hill 44 End of Main Content Because learning changes everything. ® www.mheducation.com Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.