● Anasazi - internal collapse● Key Features:○ any evolved civilization had to deal with water shortage/management○ higher elevation: precipitation, cooler temp, better suited for growing crops○ lower elevation: could dig wells that weren’t too deep○ use of irrigation○ high degree of sophistication in buildings/technology ○ successful over 600 years - longer than USA!● Q: were these societies sustainable?● A: Probably not. success created complex infrastructure that meant communities weren’tself-sufficient under adversity ex: Los Angeles is highly complicated, and not self-sustainable. needs to import goods/foods● Find evidence in archaeology○ such as Tree Rings - spacing between rings depends on conditions (ie. drought)○ no data from tropical trees b/c no seasonality○ packrat middens = pack objects, provides proof● Hopi and Zumi tribes survived! but smaller, and only at places w/ reliable water sources● Freshwater○ = relatively pure, w/ few dissolved salts○ may seem abundant, but drinkable water is rare.○ 98% Ocean, 2% Fresh water■ Fresh water >20% Ground water, 79% ice caps/glaciers, 1% surface water. ● Groundwater○ Anasazi could have possibly survived w/ use of ground water○ Q: why valuable? (provides transport)○ A: a lot cleaner, not where you use it, plentiful, reliable/not seasonal● Cycle○ Precipitation○ Confined Recharge Area (where rain falls)○ Aquifers (confined/unconfined)● The Ogallala Aquifer○ all connected under the Great plains of the US.○ largest aquifer○ however, is on overdraft - we’re taking more water than is going in.○ Groundwater Pumping in Saudi Arabia (1986-2004)● Was there any civilizaion that lacked water?○ Collapse on Maya Civilization○ climate records and written records revealed droughts were significant problems○ in 900 AD, 150 yr-long drought● Yucatan Peninsula (Mexico) = water is exceptionally clean! no rivers = no muddy water from suspended particles● Cenotes = collapse of sinkholes create craters○ occurs when groundwater is close to surface, but not surface water○ so has all advantages of ground water● Thus:○ southern Mayan cities collapsed before the northern cities○ instead of putting resources/energies into finding new ways to get water, they exhausted in war/fighting/competitionField trip to Page Museum● www.tarpits.org/la-brea-tar-pits/timeline● Pleistocene● possible that human impact caused extinction● photographs of early Los Angeles○ excavation○ large gas
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