420 likes | 586 Views
Soil Water. Water as a Resource. CIA Global Trends: Natural Resources and Environment (projections for 2015)
E N D
CIA Global Trends: Natural Resources and Environment(projections for 2015) Overall food production will be adequateto 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.
Fastest growing countries India China Pakistan ½ the world’s total agricultural groundwater use In India, 80% of domestic supply and 70% of agricultural supply is from groundwater
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.
½ China’s wheat, 1/3 corn Shallow aquifer largely depleted (replenishable) Shift to Deep fossil aquifer (non-replenishable) Agricultural well depths can exceed 1000 feet ($) Municipal well depths can exceed 3000 ft. Levels dropping 10 ft. or more / year 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.
India Population 21 million wells water table 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 Pakistan Quetta 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
Saudi Arabia al-Disi aquifer sandstone aquifer not subject to recharge Shared by Saudi Arabia and Jordan 1984 Saudi national survey reported fossil water reserves at 462 billion tons ½ has been depleted irrigated agriculture could last for another decade Wheat and Soybeans
U.S. Water Rainfall: 4,200 billion gal/day 408 billion gallons per day total withdrawal Thermoelectric power = 50% Irrigation = 30% Public-supply = 10% Industrial = 5%
1.6-2.5 gpm Guilty Pleasures 5-8 gpm http://www.youtube.com/watch?v=vMITcQUe-9M
How much water do you use? http://ga.water.usgs.gov/edu/sacsq.html
Water Usage Total 74 gallons
Peanuts: 1pound = 100 gal 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
Secondary Water Grain Livestock 3000 gallons 11 tons 1000 gallons >3 tons 650 gallons 2.5 tons ¼ pounder Quart of milk Pound of cheese Carnivores consume 100 times their weight in water each day Vegetarians consume about ½ as much.
Breakfast Toast: 40 gal Eggs: 130 gal Milk: 265 gal Coffee: 37 gal Sugar: 3 gal Total: 475 gal
Yearly Totals Drinking water: 250 - 300 gallons Total water: 1500 – 3000 tons
Factoids Americans drink more than 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 householdwater use annually: 127,400 gallons Average daily household water use : 350 gallons
Factoids It takes about 4,776 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.
How much water is there? 400 billion billion gallons 326 million mi3(one estimate)
Total Earth Water = 326 million mi3 688 miles
1 cubic mile Distance to the sun? 93 million miles
326 million mi3 0.12% of the earth’s volume Where is all this water?
Where is all the Water? Source: USGS
Freshwater Groundwater Lakes Soils Wetlands Rivers Atmosphere Biological 0.775% 0.8%
Hydrologic Cycle The hydrologic cycle takes 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.
Condensation Infiltration Runoff Evaporation Precipitation
Evaporation/Transpiration overland flow infiltration interflow percolation groundwater Fate of Precipitation
Shared electrons Water Molecule Shared electrons Bond of shared electrons O H H O H H
e- e- e- e- e- e- e- e- P+ P+ Electrons are negatively charged, protons positive Oxygen is “electron greedy” Oxygen pulls electrons toward itself and away from hydrogen O H H P+ P+ This pulling of electrons toward itself is called “electronegativity”
e- e- e- e- e- e- e- e- P+ P+ Abundant electrons (negative charge) O H H Two protons (+ charge)
Polarity _ Red = lots of e- Blue = few e- + + + Electric Dipole
+ - Polarity Slight positive charge Electric Dipole Slight negative charge
Bond + + - - Orientation Opposite charges attract each other
Hydrogen Bonding in Water Bonds are ephemeral, continuously breaking and reforming
The cohesion of water molecules is partly responsible for the overall movement and retention of water in soils Next: Movement of water: Forces and Energies