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Los Angeles Water Crisis: Where’s the Water?. What is a Water Crisis?. Definition: the available fresh water within a region is less than that region’s demand Causes may include Increased population growth Lower-than-usual annual rainfall Contamination of local water supplies
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What is a Water Crisis? • Definition: the available fresh water within a region is less than that region’s demand • Causes may include • Increased population growth • Lower-than-usual annual rainfall • Contamination of local water supplies • Effects may include • Government regulation on water usage • Increased water costs • Increased food costs
Water Crisis in Los Angeles • Los Angeles Water Supply is NOT Sustainable • Most fresh water is imported from 100+ miles away • Sierra Nevada mountains • Major rivers and deltas • Less than 50% of LA water is from local sources • This can be increased in times of drought for short periods of time
Where Does LA’s Water Come From? Top 3 Sources of LA Water San Joaquin Delta 370 miles Los Angeles Owens River 210 miles Colorado River 280 miles
The Proposed Solution • Reduce Use of Non-Local Water • Use local reservoir reserves • Reduce imported water • Increase use of groundwater (water below Earths surface) • 30% of LA water comes from groundwater (60% in a drought) Mountain Spring (Imported Source) Reservoirs (LA Source) Groundwater (LA Source)
Natural Water Requires Purification • Passive Filtering and Purification • Gravity pulls water through filter • Each filter stage traps different types of particles and microbes • Has difficulty separating extremely small particles (i.e. dissolved solutions) • Active Filtering and Purification • Pumps force water through filter • Pressurized water can be forced through smaller filter holes • Able to capture dissolved particles • High energy requirements = EXPENSIVE
Water Filtration Activity • You will now… • Build a water filtration tower with 4 filter stages • Gravel • Traps large particles in gaps between gravel pieces • Sand • Traps smaller solid particles in gaps between grains • Active carbon • Traps / absorbs substances inside small holes in surface • FUN FACT: 1 gram of active carbon has more surface area than a basketball court • Filter paper • Very small holes strain out the smallest contaminants • Filter different types of dirty / contaminated water • Analyze the effectiveness of the water filter tower • Use what you learn to “solve” the LA Water Crisis