https://zoom.us/j/92000306539?pwd=SHNmQ29aT2NnOVNjbm5JeFZYTTJPUT09Meeting ID: tophatPasscode: 628356Lecture 6What's your favorite river? Here's a story about mineSan Francisco (CNN)- Three weeks and about 400 miles ago, I started a trip down the "most endangered" river in the UnitedStates, California's San Joaquin. The underloved river is born in the Sierra Nevada and snakes acrossone of the most productive agricultural regions in the world, California's Central Valley.- I finished that journey -- which mostly involved kayaking, but also a fair bit of walking, since the SanJoaquin runs dry for about 40 miles -- on Friday beneath the Golden Gate Bridge here in San Francisco.It was a moment I'll always remember: that behemoth, cardinal-red bridge towering overhead, clangingin the wind, the distant roar of traffic, water rushing through a 1.7-mile channel that drains about 40% ofthis countrysized state's land area. The ocean tossed the kayak around like a piece of doug.2 Videos-10% of Earth’s people do not have enough water, and nearly 40% must drink and bathe in water thatdoes not meet even the most minimal standards of sanitation.-Freshwater is a limited resource and we are using it faster than it can be replenished. Althoughmethods are available to recover and purify some of the water we use, conservation is also seriouslyneeded.On the planet covered with water, why is its availability becoming a crisis?-Amount of water in the system is finite.Less than 1/100 of this water is usable by humans (Freshwater contains few dissolved ions)Of this, almost 35 million cubic kilometers are held in glaciers with additional water in rivers, lakes, andother organisms.Hydrological Cycle: linkage of all marine & freshwater aquatic environments, process of water travelfrom atmosphere -> earth -> atmosphere.- We depend on water going through state changes in the hydrological cycle. Heat causes evaporationand transpiration.- Rising gases are cooled to yield another state change back to liquid. The liquid water is returned toEarth to fill ground storage, underground storage, and to become available for uptake by plants throughtheir root systems.-At each stage within the hydrological cycle, bonds are made and broken.-Toxins may be picked up, transported, or eliminated.Watershed: The land area surrounding a body of water over which water (such as rain) could flow andpotentially enter that body of water.-The World Health Organization estimates that 1 in 3 people – more than 2 billion – lack access to cleanwater-Even more lack access to sufficient sanitation facilities 265 million gallons of raw sewage enters-The Ganges River daily 3,000 people die from water-borne illnesses in Africa daily-Predictions suggest that 2 out of 3 people will face water shortages by 2025-In many developing nations, people use nearby surface waters to meet their basic needs.-Without improved sanitation, this water is contaminated with raw sewage and other forms ofContamination.A Few DefinitionsAquifer: An underground region of soil or porous rock which is saturated with waterInfiltration: The process of water soaking into the groundWater Table: The top of the underground water-saturated region-Water trickling down into the Earth naturally fills cracks and crevices while maintaining thewater table and refilling the aquifer.-In coastal areas, such as on the Georgia coast, proximity to seawater and lower water tableshave resulted in saltwater intrusion into the freshwater sources.Where is much of Georgia getting their water?-ACT & ACF River Basins in GeorgiaHow to solve the water shortage in Georgia?-Damming rivers and creating reservoirs, like Lake Lainer, GA.-Benefits:+ Source of freshwater+ Flood control+ Electricity production+ Boating, fishing & other recreationBut there are also serious downsides:-An enormous potential for evaporation, especially during summer when we need water the most(globally, more water lost than through industry and domestic)The other serious downside is that others live downstream from us!(Tri-State water wars: River basins in dispute)-Metro Atlanta obtains 99 percent of its water water supply from rivers, lakes and streams.-Groundwater cannot be a major source of supply because the bedrock is nonporous hard rock, likeStone Mountain granite.-Rainfall is variable, from as low as 30 inches per year to as high as 70 inches per year, with an averageof 50 inches per year.-There is no natural lakes in North Georgia. Therefore, metro Atlanta must use man-made reservoirs tostore water during rainy periods to use during dry times and drought.-Buford Dam, creating Lake Lanier, was constructed in 1957-Currently there are two federal reservoirs that are used for water supply in metro Atlanta: Lake -Lanierand Lake Allatoona.-Lake Lanier is located in the Apalachicola-Chattahoochee-Flint (ACF) River Basin.-Lake Allatoona is located in the Alabama-Coosa-Tallapoosa (ACT) River Basin.Who are the players in the Tri State War?-Each state has its own concerns about the allocation of water:-Georgia: The upstream user, they are concerned that Georgia’s increasing need for water will severelylimit its own use of water for power generation, fisheries among other uses.-Alabama: A downstream user, they are concerned that GA’s increasing need for water will severely limitits own use of water for power generation, fisheries among other uses.-Florida: the other downstream user, Florida wants enough freshwater to reach the Apalachicola Bay tosupport its multi-million dollar shellfish industry.-To date, the state Georgia have spent close to $20 million in outside legal fees in thetwo-decades-long-tri-state water wars negotiating and litigating (kien tung) to preserve Atlanta’s accessto drinking water from Lake Lanier!Water scarcity will be an on on-going issue in Georgia, in part because of droughts.July 2011, January 2012, June 2012, January 2017, August 2017Solving global water shortages is not easy-Much of our water usage can be reduced by using new water efficient technologies and waste water.-Buying less stuff and using less energy also saves waterThree Gorges Dam(China is economically strong)Three Gorges Dam VideoBenefit: great economicDownside: ability to change the length of day and night. That we are not aware of it tho. Turning Yangtzeto a nightmare; people have been forced homeless because the river height rise. Phosphorus andNitrogen are increasing in the water.• Three Gorges Dam is a massive