Water Issues: Understanding Water Scarcity, Pollution, and Dam Impacts, Slides of Geology

Download Water Issues: Understanding Water Scarcity, Pollution, and Dam Impacts and more Slides Geology in PDF only on Docsity! Water Issues • Where is the Water? • Hydrologic Cycle • Water Quality and Pollution • Dams, Irrigation, and River Regulation • Invasive Species Docsity.com WHERE THE WATER IS ALL WATER af which: Oceans 97.5% Freshwater 25% of whoch: Ice caps and glaciers 79% Easily accessible Groundwater |furface 20% Vireshwater : % eff which: Lakes 52% Rivers 1% in living organisms 1% spheric water vapor 8% Source: FAD, GLOBAL LAND LAND DAMAGED BY AREA UNDER IRRIGATION, 1980s IRRIGATION Top five irrigators 1983 Million — "%of hectares irrigated of land land 1968 — damaged damaged 1973 India 20.0 36 China 70 15 1978 USA 5.2 vay Pakistan 3.2 20 1983 USSR 25 12 ‘d 3 4. 1988 Worl 60.2 2 ‘Source: UNEP, 1993 1998 O 50 190 150 200 250 300 Million hectares Source: FAD, WATER LOST IN IRRIGATION 55% water loss distribution losses 15% wae effectively us cro ae Source: FAD. POLLUTANTS IN WATER: toxins (cause damage to human body, often kidneys or liver, or cause disease or cancer) • Natural: selenium, arsenic (Bangladesh), others • Anthropogenic (human-caused): Point Source: – Industry: • heavy metals such as mercury, cadmium, chromium, lead, others (metal smelters, steel plants, dumping of sewage sludge) • thalium, mercury, selenium, arsenic ( coal burning power plants) - harms infants and pregnant women, others • Petroleum spills from ships (e.g., Exxon Valdez, 1984) and wells (e.g., Santa Barbara Channel, 1969 and Gulf of Mexico, 2010) – Agriculture: • animal waste encourages toxic bacteria growth (e. coli and others), fertilizer causes excess nitrogen and phospate/eutrophication, dioxins (from herbicides), hormones, antibiotics, DDT – Sewage: leaks, overflows - E. Coli infections result Docsity.com Water Quality • Non-point source: – Urban Storm Run-Off : • Oil Changes, Anti-Freeze, Detergents, Lawn Fertilizers, and plastics become lodged in river and marsh sediments, endangering wildlife and plants. Eutrophication Docsity.com Gulf of Mexico Oil Spill, 2010 Docsity.com The Geography of Large Dams • Over 39,000 large dams by 1986 Docsity.com The Impact of Dams • Northern third of the world: 77% overall impacted by dams and river regulation. (Dynesius and Nilsson, 1994) • Industrialized countries - more impact! – USA: 98% (Escheverria et. al., 1989) Docsity.com Upstream Impact of Dams • Built 1956-1966. • Aesthetics: Glen Canyon, Colorado River Docsity.com Downstream Impacts of Dams • Altered hydrology - no seasonality • Altered water quality/character • Modify nutrient cycling • Reduce sediment supply • Channel adjustments • Habitat modification • Species impacts • River fragmentation Docsity.com Flow of the Colorado River Hoover Dam completed (1935) NJ NO Ww oe) © on oO wm 1 ! i J Glen Canyon Dam completed (1963) = uw 1 Billion m3/yr = oO ! 55 0 ! ! ! T 1900 1915 1930 1945 1960 1975 1990 2005 Year 3 Docsity.com California’s Water System • California’s Water Projects – Los Angeles Aqueduct – Salton Sea – Colorado Aqueduct – Mono Lake Decisions Docsity.com Ca lif or ni a Hy dr og ra ph y Docsity.com Native Water Issues Distribution of surface water: 70% is in 20% of state, mostly in north. Population is mainly in south and central. Sacramento River System: 1/4 of total flow - 1/3 of this water is from the northwestern tributaries. Only 1/10 from San Joaquin. Seasonal Variation: Dry summer: water arrives when farmers least need it. Irrigation and storage are necessities. Winter flooding: In 1840’s the only way to get to Sacramento from the west was by skiff, not horse. Seasonal floods and native streams provide habitat for spawning fish, including steelhead trout and salmon. Threatened by damns and water control. Docsity.com Los Angeles Aqueduct (DWP) Eastern Sierra • Started in 1908 by William Mulholland • appropriated water feeding Owens Valley • taps surface flow from Eastern Sierra south • 250 miles, cost $25,000,000 and took five years • pipe and flume, tunnel, and trench • gravity feed, no pumping • generates hydroelectric power • L.A. purchased riparian land, used appropriation rights to get away with this. Ranchers in Owens Valley fought back with dynamite and guns - California’s only range war. Docsity.com Mono Lake • In 1941, L.A. DWP started diverting Mono Basin streams to add to L.A. Aqueduct. • Mono Lake’s volume halved while salinity doubled. The simple ecosystem began to fail and threatened migrating birds and nesting gulls. • The State of California and courts now mandate raising the level of the lake 17 feet. It will take about 20 years. Docsity.com & Sacram erie, if San Frarcisco Mokelumne Aqueduct Hetch Hetchy Aqueduct Los Angeles Aqueduct rado River duct Diego Docsity.com