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Soil Chemistry: Soil Water and porosity.ppt
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- 2. Water as aResource
- 3. CIA Global Trends:Natural Resources and Environment (projections for 2015) Overall food production will be adequate to feed the world's growing population, but poor infrastructure and distribution, political instability, and chronic poverty will lead to malnourishment in parts of Sub-Saharan Africa. The potential for famine will persist in countries with repressive government policies or internal conflicts. Despite a 50 percent increase in global energy demand, energy resources will be sufficient to meet demand; the latest estimates suggest that 80 percent of the world's available oil and 95 percent of its gas remain underground. In contrast to food and energy, water scarcities and allocation will pose significant challenges to governments in the Middle East, Sub-Saharan Africa, South Asia, and northern China. Regional tensions over water will be heightened by 2015.
- 4. India China Pakistan ½ the world’s totalagricultural groundwater use In India, 80% of domestic supply and 70% of agricultural supply is from groundwater Fastest growing countries
- 5. The water tableunder some of the major grain-producing areas in northern China is falling at a rate of five feet per year, and water tables throughout India are falling an average of 3-10 feet per year.
- 6. ½ China’s wheat,1/3 corn Levels dropping 10 ft. or more / year Shift to Deep fossil aquifer (non-replenishable) Agricultural well depths can exceed 1000 feet ($) Municipal well depths can exceed 3000 ft. Shallow aquifer largely depleted (replenishable) China’s grain production has fallen from its historical peak of 392 million tons in 1998 to an estimated 358 million tons in 2005, a drop of 34 million tons. China largely covered the drop-off in production by drawing down its once vast stocks until 2004, at which point it imported 7 million tons of grain.
- 7. India 21 million wells watertable is falling by 6 meters (20 feet) per year falling water tables have dried up 95 percent of the wells owned by small farmers drilling 1000m to reach water agriculture is rain-fed and drinking water is trucked in Population Pakistan is growing by 3 million per year, In the Punjab plain, the drop in water tables appears to be similar to that in India. In the province of Baluchistan, water tables are falling by 3.5 meters per year. within 15 years Quetta will run out of water if the current consumption rate continues Pakistan Quetta
- 8. 1984 Saudi nationalsurvey reported fossil water reserves at 462 billion tons ½ has been depleted irrigated agriculture could last for another decade al-Disi aquifer sandstone aquifer not subject to recharge Saudi Arabia Shared by Saudi Arabia and Jordan Wheat and Soybeans
- 9. 408 billion gallonsper day total withdrawal Thermoelectric power = 50% Irrigation = 30% Public-supply = 10% Industrial = 5% U.S. Water Rainfall: 4,200 billion gal/day
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- 12. Use Gallons perCapita Percentage of Total Daily Use Showers 12.6 17.3% Clothes Washers 15.1 20.9% Dishwashers 1.0 1.3% Toilets 20.1 27.7% Baths 1.2 2.1% Leaks 10.0 13.8% Faucets 11.1 15.3% Other Domestic Uses 1.5 2.1% Water Usage 74 gallons Total
- 13. How do youconserver water?
- 14. Peanuts: Domestic water use:10% Industrial water use: 20% Irrigation water use: 70% 1 pound of Rice 650 gallons 4800 pounds 1 pound of Wheat 130 gallons 1000 pounds 1 pound of Sugar 400 gallons 3000 pounds 1 pound of coffee 2650 gallons 10 tons 1 beer: 66 gallons 1pound = 100 gal
- 15. Secondary Water Grain Livestock ¼pounder Quart of milk Pound of cheese 3000 gallons 11 tons 1000 gallons >3 tons 650 gallons 2.5 tons Carnivores consume 100 times their weight in water each day Vegetarians consume about ½ as much.
- 16. Breakfast Toast: 40 gal Eggs:130 gal Milk: 265 gal Coffee: 37 gal Sugar: 3 gal Total: 475 gal
- 17. Yearly Totals Total water:1500 – 3000 tons Drinking water: 250 - 300 gallons
- 18. Americans drink morethan 1 billion glasses of tap water per day. On average, 50 to 70 percent of home water is used outdoors for watering lawns and gardens. Average household water use annually: 127,400 gallons Average daily household water use : 350 gallons Factoids
- 19. It takes about4,776 gallons of water to raise a Christmas tree. To raise the 35 million Christmas trees U.S. families enjoy each year, a total of 167 billion gallons is required. If mothers refresh their floral arrangements and flowering plants during the Mothers' Day week, they will use 2,835,000 gallons of water. After Thanksgiving dinner in 1999, 16.4 million Americans watched football. At halftime, American toilets flushed 16.4 million times and used 48.5 million gallons of water. Water efficient toilets would save us 22.3 million gallons of water. Factoids
- 20. Where is allthe Water?
- 21. How much wateris there? 400 billion billion gallons 326 million mi3 (one estimate)
- 22. 688 miles Total EarthWater = Total Earth Water = 326 million mi3
- 23. 93 million miles 1cubic mile Distance to the sun?
- 24. 326 million mi3 0.12%of the earth’s volume Where is all this water?
- 25. Where is allthe Water? Oceans, Seas, & Bays Wetlands, Swamps Lakes Soil Moisture Atmosphere Biological Water Rivers Groundwater Ice caps, Glaciers, & Permafrost
- 26. Where is allthe Water? Water source Percent of fresh water Percent of total water Oceans, Seas, & Bays -- 96.5 Ice caps, Glaciers, & Permafrost 69.6 1.79 Groundwater 30.1 1.7 Lakes 0.26 0.013 Soil Moisture 0.05 0.001 Atmosphere 0.04 0.001 Wetlands, Swamps 0.03 0.0008 Rivers 0.006 0.0002 Biological Water 0.003 0.0001 Source: USGS
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- 28. Cycling of Waterin the Environment
- 29. The hydrologic cycletakes place in the hydrosphere, this is the region containing all the water in the atmosphere and on the surface of the earth. The cycle is the movement of water through this hydrosphere. Hydrologic Cycle
- 30. Condensation Infiltration Runoff EvaporationPrecipitation
- 31. overland flow Evaporation/Transpiration groundwater interflow Fate ofPrecipitation percolation infiltration
- 32. Understanding Soil Water:The Water Molecule
- 33. O H H Water Molecule O Shared electrons Bondof shared electrons H H Shared electrons
- 34. O H H Electrons are negativelycharged, protons positive Oxygen is “electron greedy” Oxygen pulls electrons toward itself and away from hydrogen e- e- e- e- e- e- e- e- This pulling of electrons toward itself is called “electronegativity” P+ P+ P+ P+
- 35. O H e- e- e- e- e- e- e- e- Abundant electrons(negative charge) Two protons (+ charge) H P+ P+
- 36. + + _ Red = lotsof e- Blue = few e- Polarity + Electric Dipole
- 37. Slight negative charge Slightpositive charge Polarity Electric Dipole - +
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- 39. Hydrogen Bonding inWater Bonds are ephemeral, continuously breaking and reforming
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- 41. The cohesion ofwater molecules is partly responsible for the overall movement and retention of water in soils Next: Movement of water: Forces and Energies
Editor's Notes
- #5 The water table under some of the major grain-producing areas in northern China is falling at a rate of five feet per year, and water tables throughout India are falling an average of 3-10 feet per year. The reservoir beneath the Taklamakan desert has a capacity about the same as the 244-square-mile reservoir being filled behind China's massive Three Gorges Dam, newspapers and the official Xinhua News Agency said, citing a study that said the lake could produce about 35 billion cubic feet of water a year. The survey that found the lake also discovered 49 other underground sources could alleviate the need to construct 10 major reservoirs, Xinhua said.
- #6 Falling water tables are already adversely affecting harvests in some countries, including China, the world’s largest grain producer. A groundwater survey released in Beijing in August 2001 revealed that the water table under the North China Plain, which produces over half of that country’s wheat and a third of its corn, is falling faster than earlier reported. Overpumping has largely depleted the shallow aquifer, forcing well drillers to turn to the region’s deep fossil aquifer, which is not replenishable. The survey, conducted by the Geological Environmental Monitoring Institute (GEMI) in Beijing, reported that under Hebei Province in the heart of the North China Plain, the average level of the deep aquifer was dropping nearly 3 meters (10 feet) per year. Around some cities in the province, it was falling twice as fast. He Qingcheng, head of the GEMI groundwater monitoring team, notes that as the deep aquifer is depleted, the region is losing its last water reserve—its only safety cushion. He Qingcheng's concerns are mirrored in a World Bank report: “Anecdotal evidence suggests that deep wells [drilled] around Beijing now have to reach 1,000 meters [more than half a mile] to tap fresh water, adding dramatically to the cost of supply.” In unusually strong language for a Bank report, it foresees “catastrophic consequences for future generations” unless water use and supply can quickly be brought back into balance. The U.S. embassy in Beijing reports that wheat farmers in some areas are now pumping from a depth of 300 meters, or nearly 1,000 feet. Pumping water from this far down raises pumping costs so high that farmers are often forced to abandon irrigation and return to less productive dryland farming. Falling water tables, the conversion of cropland to nonfarm uses, and the loss of farm labor in provinces that are rapidly industrializing are combining to shrink China’s grain harvest. The wheat crop, grown mostly in semiarid northern China, is particularly vulnerable to water shortages. After peaking at 123 million tons in 1997, the harvest has fallen in five of the last eight years, coming in at 95 million tons in 2005, a drop of 23 percent. The U.S. embassy also reports that the recent decline in rice production is partly a result of water shortages. After peaking at 140 million tons in 1997, the harvest dropped in four of the following eight years, falling to an estimated 127 million tons in 2005. Only corn, China’s third major grain, has thus far avoided a decline. This is because corn prices are favorable and because the crop is not as irrigation-dependent as wheat and rice are. Overall, China’s grain production has fallen from its historical peak of 392 million tons in 1998 to an estimated 358 million tons in 2005. For perspective, this drop of 34 million tons exceeds the annual Canadian wheat harvest
- #7 21 million wells drilled in this global epicenter of well-drilling are lowering water tables in most of the country. In North Gujarat, the water table is falling by 6 meters (20 feet) per year. In Tamil Nadu, a state with more than 62 million people in southern India, wells are going dry almost everywhere. According to Kuppannan Palanisami of Tamil Nadu Agricultural University, falling water tables have dried up 95 percent of the wells owned by small farmers, reducing the irrigated area in the state by half over the last decade. As water tables fall, well drillers are using modified oil-drilling technology to reach water, going as deep as 1,000 meters in some locations. In communities where underground water sources have dried up entirely, all agriculture is rain-fed and drinking water is trucked in. Tushaar Shah, who heads the International Water Management Institute’s groundwater station in Gujarat, says of India’s water situation: “When the balloon bursts, untold anarchy will be the lot of rural India.”
- #8 eastern Arabia and in the Jabal Tuwayq, artesian wells and springs are plentiful
- #9 Estimates of water use for 2000 indicate that about 408 billion gallons per day (abbreviated Bgal/d) were withdrawn for all uses during the year. This total has varied less than 3 percent since 1985 as withdrawals have stabilized for the two largest uses—thermoelectric power and irrigation. Freshwater withdrawals were about 80 percent of the total, and the remaining 20 percent was saline water. Combined withdrawals for self-supplied domestic, livestock, aquaculture, and mining activities represented about 3 percent of total water withdrawals for 2000. Thermoelectric power accounts for about half of total water withdrawals. Most of the water is derived from surface water and used for once-through cooling at power plants. About 52 percent of fresh surface-water withdrawals and about 96 percent of saline-water withdrawals are for thermoelectric-power use. Irrigation accounts for about a third of water use and is currently the largest use of fresh water in the United States Saline water is defined as water with 1000 mg/L or more of dissolved solids; it is usually undesirable for drinking and for many industrial uses. Irrigation uses about 60 percent of all the water it withdraws. Compare that to thermoelectric power (which uses only 3 percent of withdrawals) and all domestic, commercial, and other industrial uses, which use about 20 percent of withdrawals.
- #10 After video: high flow = 5-8 gpm. Low flow = 1.6-2.5 gpm. Toilets went from 3.5 gpf to 1.6 gpf. Do you take long showers, leave the tap on while brushing, have a swimming pool, use a dishwasher, take baths, clean outdoors with water, keep your car impeccably clean?
- #13 Low flow shower heads, water off during brushing, dirty car, limit watering, time watering, shower
- #14 8-16 gallons of water to make one gallon of bottled water.
- #15 Carnivores consume about 100 times their weight in water each day
- #21 One estimate.
- #23 3.5 trips to the sun.
- #27 In terms of available freshwater: groundwater, Lakes, soils, wetlands and rivers yield 0.775% of total.
- #33 In other words, we have an imbalance of electrons in water. There is a greater density of negative charge near the oxygen atom due to the unbonded electrons and a slightly greater positive charge near the hydrogen atom. This is one of the features of water molecules that give them their unusual properties compared to other substances.
- #34 In other words, we have an imbalance of electrons in water. There is a greater density of negative charge near the oxygen atom due to the unbonded electrons and a slightly greater positive charge near the hydrogen atom. This is one of the features of water molecules that give them their unusual properties compared to other substances.
- #35 In other words, we have an imbalance of electrons in water. There is a greater density of negative charge near the oxygen atom due to the unbonded electrons and a slightly greater positive charge near the hydrogen atom. This is one of the features of water molecules that give them their unusual properties compared to other substances.
- #37 Water molecules behave essentially the same way. Instead of a magnetic dipole, we have an electric dipole with positve charge near the hydrogen end of the molecule and negative charge near the oxygen end of the molecule.
- #38 If we place two water molecules near each other they will behave just like the magnets. They will orient themselves so that the opposite poles align and they will be attracted to each other. They will bond electrostatically together. This bond is called a hydrogen bond.
- #39 In liquid water, the water molecules orient themselves so that their partial positive charges align with the partial negative charges of neighboring molecules to form a loose structure like that pictured here. The dotted lines represent the hydrogen bonds between the water molecules. Each of these bonds is relatively weak, less than one twentieth of that between hydrogen and oxygen within each water molecule. However they are extremely numerous. So while they are individually weak they are collectively very strong. Like strands in a rope. This makes water a very stable and a very powerful structure and imparts a number of unique properties.