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Rate of exchange for water in:
Glaciers: 8000 years
Groundwater: 280 years
Lakes: 7 years
Rivers: 11.3 days
Relative amount of fresh water in:
Terms to know:
Water table: upper limit of zone of saturation
Zone of aeration: pore spaces filled mainly with air (above water table) includes soil moisture (cannot pump water from this zone)
Effluent stream: humid climate, groundwater moves into channel
Influent stream: arid climate, downward seepage from the stream channel to the water table
Porosity: proportion of void space in material holes or cracks expressed as percentage
Permeability: measure of how readily fluids pass through the material - how well holes or cracks are connected
Porosity and permeability of:
Shale: 50 % porosity, less than 0.01 permeability
Sandstone: 5-30% porosity, 0.3 to 10 permeability
Limestone: 1-10% porosity, 0.00003 to 0.1 permeability
Granite: 0.1-5% porosity, 0.00003 to 0.003 permeability
Know about Wells and Springs
Aquifer: permeable rock that freely transmits groundwater (sandstone, limestone, sand, gravel)
Aquiclude: impermeable layers (shale, clay, massive igneous rocks)
Springs: Water table intersects earth's surface
Drawdown: drop in water table in vicinty of well
Wells: opening bored into the zone of saturation
Cone of depression: Conical shaped draw-down of water table
Geology of groundwater in Georgia
Valley and Ridge: Aquifers underlie a broad band that trends northeast through eastern Alabama and the northwestern corner of Georgia. The narrow, parallel band in northeastern Alabama is the Sequalchie Valley.
Rock type is a major factor determining aquifer yield in the Valley and Ridge physiography province. The most productive aquifers are predominately limestone.
Piedmont: Crystalline-rock aquifers underlie the rollig hills of the Piedmont physiographic province and the rugged mountains of the Blue Ridge physiographic province in a band that extends from east-central Alabama northeastward through western Carolina.
Ground water percolates downward through the unsaturated zone to the water table, then moves laterally to discharge points. In the bedrock, the water is channeled through fractures.
Coastal Plain: The South eastern Coastal Plain aquifer system underlies the entire Coastal Plain of Alabama, South Carolina, and almost all of the Coastal Plain of Georgia. The system extends into Florida for a short distance and also underlies much of the Coastal Plain of Mississippi to the west.
Ground water problems:
Subsidence: Surface Sinks - caused by heavy pumping of groundwater from sediment or drought that lowers water table
Salt water contamination: coastal areas-salt groundwater pumped toward coastal wells
Sewage: septic tanks, inadequate and broken sewer lines, barnyard waste (bacteria, nitrate, and chemicals)
Harmful bacteria: filtered by sand (filtered out, destroyed by oxidation or eaten by other organism) not filtered by limestone, gravel and highly fractured rock
Septic tanks: Bacterial action within a septic tank helps to break down the solids in the waste water that enters the tank. The tank must be large enough and the rate of flow small enough, to ensure sufficient "residence time" of waste water in the tank. Waste water flows from the tank into a drain field.
Arsenic: Naturally occurs in some groundwater at levels that are toxic. 53rd most abundant element in the earth's crust. Other sources are insecticides, herbicides, fungicides, glass and ceramics, folk remedies, metal alloys, and leathering tanning, paint pigments, fertilizers, semiconductors, light emitting diodes, and animal feed
About 140 million people worldwide drink groundwater containing unsafe levels of arsenic. Chronic exposure to this tasteless, odorless poison leads to health effects such as skin lesions and cacer. Issue in 1971 in Bangladesh. Origin from arsenic sulfides washed from ore bodies in the Himalayas and becoming part of the delta sediment submerged in the reducing groundwater. Intensive irrigation dropped the water tables bringing the sulfides into contact with oxygen. Oxidized water seeping through the sediment dissolved the arsenic that seeped into the tubes wells of Bangladesh.
Lead: natural abundance in groundwater and surface water is usually low. Thirty sixth most abundant element in the earth's crust. Lead has no known beneficial function in humans, but have many harmful health effects.
Drinking water in 1992 contained lead in 819 public water systems. Sources are batteries, radiation shielding, ammunition, glass and ceramics, and casting metals. Lead pollution in drinking water is caused by humans.
Origin of hot springs
Hot spring: water 6-9 Celsius warmer than mean annual air temperature
Eastern US: Deep circulation of groundwater geothermal gradient of 20 degree Celsius/km
Western US: heat from cooling magma
Origin of Geysers
Geyser- hot water ejected with great force at intervals
Extensive underground chambers within hot rock. Water boils at 230 Celsius at bottom of 300-meter chamber as water heats it expands and some flows out at surface. Reduced pressure lowers boiling point of deep water. Deep water Rapidly turns to stream and geyser erupts. Cool groundwater flows into chamber.
Role of limestone and groundwater: Landscapes shaped by groundwater (solution of limestone)
Caverns = cave formed by dissolving limestone in the zone of saturation (acid groundwater dissolves calcite)
Sinkholes: sinks- surface depressions. Origin 1) gradual dissolving of limestone 2) sudden collapses of cave roof
Stalactites: icicle-like, hang from ceiling
Stalagmites: form on floor
Percentage of energy usage in the US for:
- Petroleum: 34.7
- Natural gas: 26
- Coal: 17.4
- Nuclear: 8.1
- Water: 2.48
- Geothermal: 0.24
- Biomass (wood,biofuels, biowaste): 4.24
- Solar: 0.08
- Wind: 0.88
Definitions of the following:
an organic sedimentary rock consisting of a complex mixture of substances
- Peat: High Carbon 14.7 energy a brown, soil-like material characteristic of boggy, acid ground,
- consisting of partly decomposed vegetable matter. It is widely cut and
- dried for use in gardening and as fuel.
- Lignite: 5-35% Carbon 30 Energy a soft brownish coal showing traces of plant structure, intermediate between bituminous coal and peat.
: 45-85% Carbon 35 Energy
a black viscous mixture of hydrocarbons obtained naturally or as a residue from petroleum distillation
: 86-97% Carbon 36 Energy
coal of a hard variety that contains relatively pure carbon and burns with little flame and smoke
Origin of coal
First step involved chemical decomposition of plant matter assisted by organisms. Involves the rapid decay of water soluble substances and slow decay of carbohydrates, protein & lipids. Peat is produced in this stage. Peat is formed from the deposition of organic material with a restricted supply of oxygen. Peat forming environments are swamps.
Second step occurs when overburden is deposited on top of the peat, heat and pressure change the chemistry and structure of the altered organic material.
Water is squeezed out and pore size reduced as pressure increases and oxygen and hydrogen are released during thermal cracking.
Coal production in the US and China
Coal makes up ~17.4% of US energy usage. Generates 37.4% of US electricity in 2011. Coal makes up largest reserves of energy. Coal is an organic sedimentary rock consisting of a complex mixture of substances.
China is now the world's largest producer and consumer of coal. 71% of China's energy is generated from coal - some of this is burned in homes for cooking and heating. Has 13% of wolds coal reserves. Generates 69% of electricity from coal. Imported 126 million tons of coal in 2009. 14% of world's CO2 emissions.
Amount of coal reserves in the US and how long they could last