Water

What is the water table? What occurs where the water table intersects with the surface? What causes a well to go dry?

2 types of aquifers: • Unconfined aquifer = aquifer in which the layers of rock above are porous and allow surface water directly above them to seep downward, replacing the aquifer contents • The upper limit of an unconfined aquifer, below which the ground is saturated with water (saturated zone), is called the water table • In deserts, the water table is generally far below the surface • Lakes, streams, and wetlands occur where the water table intersects with the surface • When a well goes dry, the water table has drop

Who got a share of the water in 1944? What was the main problem with these agreements? What has happened to the Colorado River Delta? How have San Diego and Los Angeles been able to keep pace with the water needs of their growing populations?

A 1944 treaty gave Mexico a share of the river water • The Colorado R. Compact and the Mexico treaty overestimated the flow of the river, so now these allotments have made it so very little or no water reaches the Colorado R. Delta and the Gulf of CA • The lower Colorado has become saltier than ocean water in some places • Imperial Valley farmers have agreed to sell some of the water they would use for irrigation to San Diego and Los Angeles

What are the characteristics of a eutrophic body of water? What is an example?

A eutrophic body of water has: • High nutrients (enriched) • Poor light penetration • Low dissolved oxygen • Shallow waters • High algal growth • Large populations of aquatic organisms • Increased sediment accumulation rate • Silt, sand, or clay bottom (mud) • Ex - Lake Erie in spring

What is a harmful algal bloom? Which algae are often responsible? How can this affect humans? What is a HAB called when the number of dinoflagellates is so high that the water changes color?

A harmful algal bloom (HAB) occurs when the algae have negative effects on other organisms via production of natural toxins • Ex - dinoflagellates produce toxins that can kill fish (and humans, if we eat shellfish that have filtered these dinoflagellates out of the water and concentrated the poison) • Number of dinoflagellates in the water can become so large that the water turns red - this is commonly called a red tide

On a graph of distance downstream from a sewage spill vs. concentration of dissolved oxygen, where is BOD highest? What happens to BOD downstream? Why?

A large amount of sewage or organic material dumped into water creates a large BOD, robbing the water of oxygen • Note on the graph that: • BOD is highest at the point of the sewage spill, and decreases downstream as the sewage is diluted and degraded

What fraction of the U.S. population uses groundwater for drinking? What are some large U.S. cities that depend entirely on groundwater? What percentage of irrigation water comes from groundwater?

About half of the U.S. population uses groundwater for drinking • Many large cities, such as Tucson, Miami, San Antonio, and Memphis, have municipal well fields and depend entirely on groundwater for drinking • 40% of the water used for irrigation in the U.S. comes from groundwater

What are the 5 steps that occur during an algal bloom caused by cultural eutrophication?

Algal blooms occur during cultural eutrophication - the sequence of events is as follows: • Nutrients, such as nitrogen, phosphorus, or organic material, are introduced into the water • Algae and plants grow and multiply quickly with the introduced excess nutrients • Algae have a short lifespan, resulting in a large amount of dead organic matter that begins to decay • The decay organisms multiply, and the decay process uses up the dissolved oxygen in the water • Hypoxic conditions result in die offs of other organisms, such as fish and invertebrates

What are the characteristics of an oligotrophic body of water? What is an example?

An oligotrophic body of water has: • Low nutrients • Good light penetration • High dissolved oxygen • Deep waters • Low algal growth • Small populations of aquatic organisms • Rock, gravel, or sand bottom • Ex - Crater Lake, Oregon

What is the main factor causing global water problems to become more serious? What percentage of the available water is located in Asia? Why do they still have a water shortage?

As the world's population continues to increase, global water problems become more serious • Asia has the world's largest available water resources (36%) of the total • But it is home to 60% of the world's people - creates water shortage

What continent has the most agricultural land under irrigation? What 3 countries dominate in terms of irrigated land? Why?

Asia has the most agricultural land under irrigation • China, India, and Pakistan account for most of it - necessary to feed their huge populations

How much water does the average American use per day? How is this split between indoor and outdoor use? What are the two biggest indoor uses for water?

Average American uses 100 gallons of water per day • 70 gallons/day indoor use • Toilet is biggest use, followed by washer, shower, faucets, and leaks • 30 gallons/day outdoor use • Lawn sprinklers and car washing

What is channelization? What are 3 advantages to channelization?

Channelization = a method of river engineering that widens or deepens rivers to increase the capacity for flow volume • Advantages: • Prevents damage to river banks during high flow times • Prevents flooding at the channelized portion • Allows building or farming near the river without risk of flooding

What type of well is formed by drilling into a confined aquifer? Why does this type of well often not require pumping?

Confined (artesian) aquifer = a groundwater storage area between impermeable layers of rock • Water is trapped and usually under pressure • If a well is drilled into a confined aquifer, the pressure will cause water to flow to the surface, forming an artesian well (water does not need to be pumped to the surface, as it flows upward under pressure from below)

What is cultural eutrophication? What are 5 human activities that cause it? Explain how agriculture causes eutrophication.

Cultural eutrophication = overnourishment of an aquatic ecosystem by nutrients such as nitrates and phosphates due to human activities, such as: • Agriculture • Fertilizer contains nitrogen and phosphorus, essential nutrients for photosynthetic organisms • Causes an algal bloom (rapid reproduction of algae)

What is desalination? Name and define the 2 major types of desalination.

Desalination = the removal of salt from ocean or brackish water • 2 major types: • Distillation = heat saltwater until water evaporates, leaving salt behind (then condense the water vapor to produce freshwater) • Reverse osmosis = force saltwater through a membrane that is permeable to water but not salt • Most popular filtration system for desalination • Less expensive than distillation because requires less energy

Where do disease-causing agents that cause water pollution originate? What are 3 bacterial examples? What are 2 viral examples? What are 2 protozoan examples? What are 2 worm examples?

Disease-causing agents are a type of water pollution • These agents originate in the fecal wastes of infected individuals • Common disease-causing agents include bacteria such as: • Vibrio cholera - causes cholera • Shigella dysenteriae - causes dysentery by producing shiga toxin • Salmonella typhi - causes typhoid fever • Disease-causing viruses: • Hepatitis virus • Poliovirus - causes polio (currently only in Pakistan and Afghanistan) Protozoans: • Cryptosporidium - caused an outbreak of diarrhea in Milwaukee in 1993 that affected 370,000 • Entamoeba histolytica - causes amoebic dysentery Worms • Schistosoma - causes schistosomiasis - liver, intestine, and bladder disease with snails as the intermediate host • Ancyclostoma - hookworm - sucks blood in the intestine

What technique is much more efficient? How does it work? Where are the best systems located? How much does it reduce water use over center-pivot irrigation?

Drip irrigation is much more efficient • Also called trickle irrigation or microirrigation • Pipes with tiny holes drilled in them deliver water directly to individual plants • Best systems are subsurface, delivering water directly to plant roots • Reduces water use by 40-60% over flood or center-pivot irrigation

What are the economic effects of the fertilizer-induced Gulf of Mexico dead zone? Which organisms are especially vulnerable?

Economic impacts of fertilizer flow into the Gulf of Mexico, causing the dead zone: • Decreased revenue due to lower fish catches • Especially affects bottom dwellers, such as shrimp, oysters, and some fin fish

What ancient civilization famously relied on the annual flooding of the Nile River? What was left behind when the flood waters receded? What activity was made more productive by this flooding?

Egyptians relied on annual flooding of the Nile River • When the floodwaters receded, a thin layer of sediment was left behind that was rich in organic material • This organic material enriched the soil, making farming more productive (allowed farming in the desert)

What are the benefits of dams?

Ensure a year-round supply of water for: • Agriculture, industrial, and domestic use • Generate inexpensive and clean electricity • Flood control Increase navigable waterways, which can be used for: • Boating • Fishing • Reduced air pollution by reducing dependence on fossil fuels for electrical generation

What causes natural eutrophication to occur? How does the lake change over time?

Eutrophication happens naturally over time • Lake slowly becomes enriched and shallower over time from the immense number of dead organisms that have settled, as well as other sediment that has entered and accumulated at the bottom of the lake • Eventually the sediments fill the lake bed, forming a meadow with grasses and shrubs - it's now a land biome

What forms every spring in the northern Gulf of Mexico? What is the cause of this phenomenon? Explain the steps involved in this phenomenon.

Every spring, a dead zone forms in the northern Gulf of Mexico • Due to nutrient input into the ocean from the Mississippi River • These nutrients are nitrates andphosphates from fertilizer use in the Mississippi basin, which has a huge amount of agricultural activity • Nutrients cause an algal bloom, after which they die and sink to the bottom • Bacteria decompose the dead algae, depleting the oxygen • The stagnant, hypoxic water is trapped near the bottom by the warmer spring/summer water near the surface • Oxygen ranges from 1-10 mg/L in the ocean - when the value gets down to hypoxic levels marine life either flees or dies (normally at levels less than 2 mg/L)

What is the chemical formula for water? What is a unique property of water at normal Earth temperatures?

Formula is H2O • Consists of 2 hydrogen atoms, each of which is bound to the lone oxygen atom • One of the few substances that can exist as a solid, liquid and gas at normal Earth temperatures

Too little water is a problem in what type of lands? What country has a huge supply of freshwater? What is the freshwater availability as a whole in the U.S.?

Freshwater availability: • Canada has a huge supply • U.S. as a whole has plentiful freshwater

What is gray water? What can it be used for? What country has the most advanced system for treating and reusing municipal wastewater? What do they use the reclaimed water for? Even though this water has pollutants, why is it still useful for irrigation?

Gray water = water that has already been used for a relatively nonpolluting purpose, such as showers, dishwashing, and laundry • Gray water is not potable (drinkable), but it can be reused for toilets, plants, or car washing • Systems can be installed to collect, store, and use gray water • Israel has the most advanced system for treating and reusing municipal wastewater • Use reclaimed water for irrigation, and save high-quality water for municipal uses • Used water contains pollutants, but most of these are nutrients from treated sewage and are beneficial to crops

What is meant by the fact that water has a high heat capacity? What impact does this have on the temperatures of places located close to bodies of water?

High heat capacity • Good at absorbing heat, and once it has acquired heat, it is slow to give it up • This property moderates temperature (Santa Monica, close to the ocean, rarely gets very hot or very cold)

What are 4 ways in which urban development (e.g. cutting down a forest and replacing it with buildings and pavement) affects the hydrologic cycle? Explain why each of these effects occurs.

Human urban development (e.g. cutting down a forest and covering parts of the land with buildings, roads, and parking lots) affects the hydrologic cycle by: • Decreasing evaporation • Less surface water in contact with the atmosphere • Decreasing transpiration • Fewer plants • Increasing runoff • Less water is able to enter the soil and become part of the groundwater, so more leaves the area as runoff • Decreasing groundwater recharge • Water is not able to enter the soil and replenish the groundwater (recharge) when it is covered with buildings and pavement

Besides the fact that more building increases the potential for damage, what are 3 other negative effects on the water cycle of constructing buildings?

Humans construct buildings on floodplains, increasing the potential for damage - buildings also: • Decrease evaporation and transpiration • Increase surface runoff • Decrease groundwater recharge

What are 2 reasons why modern floods are more disastrous in terms of property damage than ancient floods? How does the cutting of forests affect runoff?

Humans often remove water-absorbing plant cover from the soil • Forests, particularly on hillsides and mountains, trap and absorb precipitation, providing nearby lowlands protection from flooding • Cutting forests causes rapid runoff during heavy rainfall, causing flooding and increased erosion • Humans construct

What are 3 advantages of using recycled water for industry?

Industries can cut production costs, pollution, and water usage by

What factor is tightly linked to water consumption?

Irrigation

What has increased the agricultural productivity of arid and semiarid lands? Why is the amount of irrigated land going up so fast? How much has it increased since 1955?

Irrigation increases the agricultural productivity of arid and semiarid lands • Irrigation has become increasingly important worldwide • Population is going up rapidly, so more land must be irrigated in order to supply the increased food demand • Since 1955, the amount of irrigated land has tripled

Why is water a liquid at room temperature? Why is water called the universal solvent? Why do most things dissolve in water?

It is good at dissolving (pulling apart) any substance with a charge • Most substances have some charge, so most things dissolve in water

What do LEPA and GIS stand for? How does this irrigation method work? How efficient is it?

LEPA = low-energy precision application • Newer form of irrigation • Utilizes GIS (geographic information systems) • Involves dragging hoses across fields in a computer-controlled pattern • Water is released only when and where needed • GIS uses signals from satellites to identify locations for irrigation (within 8 inches or less of the target plants) • LEPA and GIS used together is 90-95% efficient (similar to drip irrigation)

Lack of water in the West has forced a reliance on what structures? What do they do? What is a famous example?

Lack of water in the West and Southwest has forced a reliance on aqueducts • Aqueducts divert water from distant sources and transport to places that do not have enough local water • Ex - L.A. Aqueduct brings water from the Owens River in the Eastern Sierra to Los Angeles

What have many local governments done to prevent building on floodplains? What is one main problem of building levees to hold back rivers? What is a famous example?

Many local governments around the world have put zoning restrictions in place to prevent building on floodplains • Levees built to hold back rivers often fail • Ex - Hurricane Katrina and New Orleans flooding

What region has the lowest amount of naturally available freshwater per capita? What are 2 reasons why India and China have fairly low freshwater availability?

Middle East has the lowest amount of naturally available freshwater per capita • Lowest per capita is Kuwait, followed by Bahrain, UAE, Egypt, and Qatar (Bahamas, Saudi Arabia, Sudan, Yemen, Maldives, and Israel are also very low) • India and China have fairly low availability (populations are so big, and they irrigate a lot for agriculture)

In 1941, Los Angeles began diverting water from the creeks that feed what lake? What did this do to the water level? What happened to the salinity? What phenomena became more common as the dry lake bed was exposed?

Mono Lake is a saline lake in the Eastern Sierra • In 1941, Los Angeles began diverting water from the creeks that feed Mono Lake into the L.A. Aqueduct • The diversion of the inflow caused the water level in the lake to drop 46 feet • The salinity of the lake doubled, disrupting the ecosystem and making it too salty for most things to live • Dust storms on the exposed dry lake bed threatened air quality • The courts halted diversions in 1989, and an agreement was reached between L.A. and environmental groups, which has brought the lake level up to about 72% of its original volume

Why can South America support only a small population, even though there is a high amount of rainfall? Why can Asia support a large population?

Most of South America's precipitation falls in the Amazon Basin, but the soil here is poor and unsuitable for large-scale agriculture • So not many people can be supported here, whereas in Asia most of the rain falls on land suitable for agriculture, allowing it to support a large population

Which portion of the U.S. is arid or semiarid land? What has water historically been used for in this area? What uses now compete for the available water, and why? What has cut down on the available water?

Overall, the U.S. has a plentiful supply of freshwater • Many areas, though, have severe shortages, due to geographic variations and seasonal variations in temperature and rainfall • Much of the American West and Southwest is arid or semiarid • Historically, water in these regions was used primarily for irrigation, but municipal, commercial, and industrial uses now compete heavily for available water • Reason for the increase is the large growth of the population in the West • Reduced snowfall, apparently caused by climate change, has cut down on the available water

What is often the problem with people and water? What is a good example?

People and water are often not in the same places • Ex - India has 20% of the world's people, but has access to only 4% of the world's fresh water

Water is a polar molecule. What does this mean? What type of bonds form between water molecules due to this polarity? What atoms are connected by these bonds, and are these bonds strong or weak?

Polar molecule • Oxygen end is slightly negative, and each hydrogen is slightly positive • Polarity allows water to form weak hydrogen bonds (between the H of one water and the O of another water) • H-bonding accounts for the fact that water is a liquid at room temp (H-bonds are continually breaking and reforming - if the bonds were strong, water would be a solid at room temp, and if they were weaker, water would be a gas at room temp)

What is recharge? What is the recharge area for an unconfined aquifer? Where is the recharge area for a confined aquifer often found?

Recharge = the process in which surface water moves downward (infiltrates) the ground, becoming groundwater and entering into aquifers • The recharge area for an unconfined aquifer is the entire land surface above the aquifer • The recharge area for a confined aquifer may be hundreds of kilometers away

What region carries out the most desalination? What country has the largest desalination plant, and obtains the greatest percentage of its drinking water from desalination? Where is the largest plant in the Western Hemisphere?

Region with the most desalination is the Middle East • Saudi Arabia has the world's largest desalination plant • Saudi Arabia obtains 70% of its drinking water from desalination • Israel also obtains a large amount of its freshwater via desalination • Carlsbad (San Diego) has the largest desalination plant in the Western Hemisphere (50 million gallons/day)

What are 2 compounds that can be dispersed into clouds during cloud seeding? What happens to these crystals inside of clouds? Cloud seeding causes the formation of what, which normally would not form? What is a potential drawback of cloud seeding?

Silver iodide crystals or dry ice are dispersed into clouds via flares mounted on the wings of a plane • Droplets of supercooled water attach/condense onto the silver iodide crystals and freeze, causing the crystals to increase in size • When the crystals get large enough they fall, melt, and become rain - allows raindrops to form when they normally would not • Effects of silver iodide on the environment are not well-studied

What is surface water? What are 3 main classes of surface water? What is runoff? What percentage of the total precipitation becomes runoff?

Surface water = precipitation and snowmelt that remains of the surface of the land and does not seep down through the soil - includes: • Streams and rivers • Lakes, ponds, and reservoirs • Wetlands • Runoff = precipitation, including snowmelt, that does not infiltrate the ground or return to the atmosphere by evaporation • Encompasses about 39% of all precipitation

Where is the Aral Sea? What 2 rivers supply it with water? What did the Soviets do to these rivers? Why was this done? What happened to the Aral Sea due to this diversion?

The Aral Sea straddles Kazakhstan and Uzbekistan • In the 1950s, the Soviet Union began diverting the 2 major rivers that supply the Aral Sea with water, the Amu Darya and Syr Darya, to irrigate the surrounding desert for cotton farming • The Aral Sea was once the world's 4th largest freshwater lake • The lake has shrunk by more than 80% • All 24 fish species originally found there are gone

What structure was built to control the flow of the Nile and prevent flooding? What is a floodplain?

The Aswan High Dam was built to control the flow of the Nile and prevent flooding • Floodplain = the area bordering a river channel that has the potential to flood

What is the major river supplying water to the American Southwest? What major cities does it supply with water? What agreement was reached in 1922, and what did it say?

The Colorado River is fed by snowmelt in Colorado, Utah, and Wyoming • It flows through Arizona, then along the border between California, Nevada, and Arizona, before entering Mexico and emptying into the Gulf of California • Supplies water for 30 million people, including the cities of Denver, Las Vegas, Salt Lake City, Phoenix, Los Angles, and San Diego • Has 49 dams along it, 11 of which provide hydroelectric power • The Colorado River Compact in 1922 allotted 7.5 million acre feet (a square acre covered one foot deep with water) to the lower Colorado R. (CA, NV, AZ, and NM), with the remainder going to the upper Colorado (CO, UT, WY)

What 4th largest river in North America is the most heavily dammed river in North America? What 2 things were done to help restore salmon populations?

The Columbia River is the 4th largest river in North America • Over 100 dams - 19 are major hydroelectric generators • Supplies water to Portland, Seattle, and Boise • Has had a major negative effect on salmon populations • Endangered Species Act was invoked to protect all salmon in Pacific Northwest rivers • Fish ladders help, but not enough

What dams were removed in Washington State in 2012? What effect did this have on sediment flow and salmon?

The Elwha and Glines Canyon dams on the Olympic Peninsula of Washington state were removed in 2012 • Allowed stored sediments to rebuild the mouth/delta of the Elwha River • Allowed salmon to once again travel upstream (impossible since 1912)

What is the largest groundwater deposit in the world? Where is it located? How many times faster is the groundwater being removed than nature is replacing it in some areas?

The Ogallala Aquifer is the largest groundwater deposit in the world • Located in the upper Midwest U.S., centered on Nebraska and stretching south into Colorado, Kansas, Oklahoma, Texas, and New Mexico • In some places, water is being withdrawn for agriculture 40 times faster than nature is replacing it

What test can be used to test for the presence of disease-causing agents in water? This technique tests for the present of which bacterium?

The presence of diseasecausing agents in a water sample can be detected using a fecal coliform test • Tests for the presence of E. coli in a sample of water

What is the world's largest dam and hydroelectric facility? Where is it located? What issues occurred as a result of constructing the dam and reservoir?

Three Gorges Dam • Located on the Yangtze River in China (longest river in Asia and 3rd longest in the world) • World's largest hydroelectric facility • The construction of the dam and the resulting reservoir: • Displaced 1.3 million people, who were relocated to new cities and towns • Flooded significant cultural and archaeological sites • Altered the ecology of the river

Briefly describe the hydrologic cycle. What is transpiration? What process carried out by most organisms releases water vapor to the atmosphere?

Water cycle = hydrologic cycle • Water at Earth's surface evaporates, cools as it rises, condenses, then falls back to Earth as precipitation • Plants give off water vapor into the atmosphere from their leaves in a process called transpiration • Organisms that do aerobic respiration (animals, plants, and most other organisms) give off water vapor during cellular respiration

What is a watershed (drainage basin)? The Colorado River drainage basin encompasses what percentage of the total land area of the lower 48 states?

Watershed (drainage basin) = the area of land drained by a single river or stream • A watershed is the land from which runoff drains into a particular stream • Ex - the Colorado River drainage basin encompasses about 1/12 of the total land area of the lower 48 states

What is water used for? What are 2 reasons why our usage of fresh water is increasing?

What is water used for? • Cooking • Washing • Agriculture • Manufacturing • Mining • Energy production • Waste disposal • Our usage of fresh water is increasing • Population is increasing • Water usage per individual is increasing

What does sewage do to BOD? What does this do to dissolved oxygen levels? How does this affect organisms? Why does the water eventually smell bad?

When sewage enters water, microorganisms begin to decompose it, using up the oxygen in the water • Sewage creates a high BOD • When O2 drops too low, fishes and other organisms die • Eventually anaerobic organisms go to work, giving off gases that further deteriorate the water, and smell bad as well

What is xeriscaping? What should be removed from the yard, and what should be planted instead? What should be used for ground cover?

Xeriscaping = landscaping and gardening that reduces or eliminates the need for supplemental water from irrigation • Get rid of lawn • Plant drought-tolerant plants • Use ground cover that doesn't require water, such as bark, gravel, or stone

Homes and buildings can be modified to match water ___________ to water __________.

quality; use

What two ions are most prevalent in seawater? Why does water become easily polluted?

salts in seawater include: • Chloride ion (19.3 g/L) • Sodium ion (10.7 g/L) • Many of the substances water is able to dissolve cause water pollution

What percentage of Earth's water is seawater? Freshwater? Of the freshwater portion, most is tied up in what form? Of the available freshwater, what percentage is groundwater? What percentage of all the water on Earth exists in the form of lakes, rivers, and atmospheric water?

• 97.5% seawater • 2.5% freshwater • Ice caps and glaciers make up 1.97% (most) of Earth's fresh water (inaccessible to us) • 2.5 - 1.97 = 0.53, so only about 0.5% of the water on Earth is available freshwater • Of the 0.53% that is available freshwater, 94% of it is groundwater • So 6% of the available freshwater, which comes out to 0.03% of all the water on Earth, exists in the form of lakes, rivers, and atmospheric water

How do nearby agriculture and logging affect sediment flow?

• Agriculture • Increased agricultural runoff increases erosion, increasing the sediment load in the river • Deforestation/logging • Increases erosion, increasing the sediment load to the river

What are some general methods that can be used to deal with eutrophication?

• Apply herbicides to kill nuisance plants/algae • Dredge lakes to deepen them • Pump oxygen into the deep waters of the lake • Introduce insects that feed on nuisance plants/algae

What often happens to the land above an aquifer composed of porous sediments that has been depleted? What is a sinkhole? Where are sinkholes common Why?

• Aquifer depletion from porous sediments causes subsidence (sinking) of the land above it • Some parts of the San Joaquin Valley in Central California have sunk almost 10 m (33 ft) in the past 50 years • Florida has bedrock made of limestone, and sinkholes are common • Sinkhole = surface depression where an underground cave roof has collapsed • Excessive pumping and lowering of the water table means sinkholes occur more frequently

Why is water never completely pure in nature? What is the average salinity of seawater? If you evaporate 1,000 g of seawater, how many grams of salt will remain?

• Because of its dissolving power, water is never completely pure in nature • Ex - seawater has an average salinity (quantity of dissolved solids) of 35 parts per thousand (1,000 g of seawater contains 35 g of dissolved salts)

What does BOD stand for? What is the definition of BOD? How is it usually expressed?

• Biological oxygen demand = the amount of oxygen microorganisms need to decompose biological wastes into CO2, water, and minerals • Expressed as mg of dissolved oxygen per liter of water for a specific number of days at a given temperature

How has building dams altered the natural flow of sediments into Gulf Coast ecosystems?

• Blocks flow of sediment from upstream, decreases deposition of sediment downstream (coast/delta is starved of sediments)

How does center-pivot irrigation work? Why is it so inefficient? What technique can be used to level fields? How does this save water?

• Center-pivot irrigation is more efficient than flood irrigation, but less efficient than drip irrigation • A line of sprinklers rotates around a pivot point • Water is sprayed in small drops, so much is lost by evaporation • Laser-leveling of fields saves water • A laser beam sweeps across a field, allowing a field grader to receive the beam, scrape the soil, and make it perfectly level • If field is not level, extra water is necessary to ensure plants at higher points in the field get enough water • Laser-leveling prevents runoff

How does channelization affects sediment flow? What about building levees

• Channelization • Prevents deposition of sediment in adjacent wetlands • Increases stream velocity and decreases deposition in the floodplain and along the coast (sediments are carried offshore) • Building levees • Prevents deposition of sediment in wetlands and increases sediment deposition at the mouth of the river or further offshore • Increases flow velocity, so sediment is carried offshore (delta is shrinking, as are wetlands)

What 5 industries use 90% of the industrial water?

• Chemical products • BASF (Germany) is the world's largest chemical company, followed by Dow (U.S.) • Paper and pulp • Petroleum and coal • Primary metals • Food processing

Besides drip irrigation and laser-leveling, what are some other strategies to reduce agricultural water consumption?

• Choose crops that don't require irrigation in that climate • Selectively breed drought tolerant crops • Irrigate at night, when evaporative loss is lower • Transport irrigation water in pipes to minimize evaporation • Direct sprinkler heads downward • Use windbreaks to minimize evaporation • Cover surface with mulch to reduce evaporative loss

What are 2 problems with decreasing sediment downstream? What does water diversion do to salinity? What is an example?

• Decreased nutrient-rich sediment downstream • Decreases plant growth/NPP, and disrupts food chain/web • Coast/delta starved of sediment • Increased salinity with decreased water volume • Decreases plant growth and animal health (e.g. Mono Lake)

What effects can decreased water volume have downstream from water diversion or dams? What does diverted water often contain after returning from diversion?

• Decreased water volume downstream/below dam • Less dissolved oxygen • Increased water temp • Lowers water table/decreased recharge of aquifers • Water taken from one place to supply another causes you to end up with two deserts instead of one • Diverted water returns with pollutants/fertilizers • Decreases dissolved oxygen

On the above graph, where does dissolved oxygen reach its minimum value? Why? What happens farther downstream in terms of BOD and dissolved oxygen? Why?

• Dissolved oxygen begins to drop at the site of the spill, and keeps decreasing until it reaches a minimum a little ways downstream (it takes awhile for the sewage to get decomposed, so it takes awhile for the oxygen level to reach its minimum - at this point the fish population will reach its lowest numbers) • The stream begins to recover further downstream as the sewage is diluted and degraded, causing BOD to decrease and dissolved oxygen to come back up to normal

What strategies can be used to reduce the flow of nutrients into the Mississippi River?

• Establish riparian (stream-side) buffer zones, with plants that trap fertilizer before it enters the river • Limit farming near floodplains • Limit fertilizer use, or apply it when less runoff will occur • Treat storm water to reduce nutrients before releasing into river • Treat waste from livestock farms

What are 3 problems with desalination?

• Expensive- requires a large energy input (reverse osmosis requires less energy, but still requires some), Must transport desalinated water from where it is produced to where it is used, Currently costs 3-4 times what conventional water costs •Disposal of the salt/brine- Dumping it back into the ocean harms marine organisms • Requires intake of large amounts of ocean water- Marine organisms in the water are killed during intake/filtration/heating

Where do experts recommend building levees? What are 3 benefits to this strategy?

• Experts recommend building levees farther away from the river, allowing the river to flood naturally (prevents property damage, enriches soil, and provides habitat for wildlife)

What is groundwater? What is an aquifer? Name and define the 2 types of aquifers?

• Groundwater = the supply of fresh water under Earth's surface that is stored in underground aquifers • Aquifer = underground caverns and/or porous layers of sand, gravel, or rock in which groundwater is stored • Two types of aquifers: • Unconfined (artesian) • Confined

Which areas in the U.S. are overdrawing the groundwater? What can withdrawal of too much groundwater cause to happen in areas along the coast?

• Groundwater has been overdrawn for irrigation in many arid and semiarid areas (dark brown areas on the right) • Withdrawal of too much groundwater has caused saltwater intrusion along the coasts of California, Washington, Texas, Florida, and Hawaii

What are the environmental consequences of damming a river?

• Habitat alteration and displacement of native species • River habitat is converted to a reservoir habitat • Decline of migratory fish species, or disruption of fish migration • Ex - salmon must travel to stream they were born in to mate (fish ladders can alleviate this problem) • Downstream areas deprived of: • Sediments • Coast delta is starved of sediments • Lack of sediment deposition on floodplain alters habitat and makes farming more difficult • Aswan High Dam on the Nile River in Egypt has caused most of the nutrientrich silt to be deposited behind the dam, instead of being deposited downstream where it can support agriculture • Nutrients • Water • Increased flow velocity downstream increases erosion

What are the disadvantages to channelization? What is a famous example of a channelized river?

• Increased speed of flow on the channelized portion increases the risk of flooding downstream on the unchannelized portion • Causes loss of wetlands adjacent to the river • Rapid flow increases soil erosion • Reduces habitats in the stream, by eliminating riffles and pools • Straightens the river, taking away its natural beauty • Ex - the L.A. River has been channelized and lined with concrete to prevent flooding

What are some strategies for conserving water at home?

• Installing water-saving showerheads and faucets (WaterSense fixtures are recommended by the EPA) • Installing low-flush toilets • Flushing toilet less frequently • Taking shorter showers • Fixing leaky fixtures • Purchasing high-efficiency appliances (such as washers) • Using the dishwasher instead of washing by hand • Turning off the tap while brushing teeth or shaving

What process generally makes inefficient use of water? What is flood irrigation? How efficient is it? Why is it so inefficient?

• Irrigation generally makes inefficient use of water • Flood irrigation is inefficient • Water is pumped through unlined ditches, where it flows by gravity to the crops being watered • Plants absorb 40% of the water - the rest evaporates or seeps into the soil • Method used in developing countries

In order, what are top 3 uses for water worldwide? Which use dominates in each of the following countries: U.S., India, Lithuania?

• Main uses for water worldwide: • Agriculture = 70% • Industry = 22% • Domestic = 8% • Usage varies by area/country • Industry uses the most water in the U.S. • Agriculture uses the most water in India (by far) • Domestic use is dominant in Lithuania (little industry or farming)

Dams cause what problems for salmon?

• Problems w/dams for salmon: • Harder to migrate upstream • Slower water means it takes longer for juveniles to migrate downstream • Slower water makes it easier for predators to catch juveniles • Altered water temperature alters salmon behavior • Fewer nutrients for young

What is sediment pollution? What are the sources of excess sediments? What are 3 problems caused by excess sediments? How are corals affected by excess sedimentation?

• Sediment pollution = excessive amounts of suspended soil particles • Where do excess sediments come from? • Erosion of agricultural lands • Forest soils exposed by logging • Plants stabilize the soil, keeping it from washing into waterways during rain • Degraded stream banks • Overgrazed rangelands, exposing bare soil • Strip mines • Construction • Problems with excess sediments: • Limits light penetration • Makes photosynthesis (PS) difficult • Covers aquatic animals/plants • Coral reefs get covered with sediment, making it impossible for zooxanthellae to do PS (coral dies as a result) • Brings insoluble toxins into waterways

What is sewage? What 3 things are included in sewage? What are 3 environmental problems caused by sewage?

• Sewage = wastewater from drains or sewers (from toilets, washing machines, and showers) - includes: • Human wastes • Soaps • Detergents • 3 environmental problems due to sewage: • Carries disease-causing agents • Enrichment = the fertilization of a body of water, due to the presence of high levels of plant and algal nutrients, such as nitrogen and phosphorus • Increase in biological oxygen demand (BOD) • Also called biochemical oxygen demand

How will climate change affect water availability? What are 2 potential issues regarding climate?

• Some areas will get more rainfall, others will get less • Reduced snowfall impacts water resources downstream • Ex - less water in the Colorado River if less snowmelt • Sea level rise will cause saltwater intrusion into coastal drinking water supplies

It is estimated that how many people lack access to safe drinking water? How many lack access to satisfactory wastewater and fecal waste disposal?

• The WHO (World Health Organization) estimates that 1.1 billion people lack access to safe drinking water • 2.6 billion lack access to satisfactory domestic wastewater and fecal waste disposal

Many developing countries have a lot of water, but what are two issues regarding the water? What percentage of human illness results from insufficient or poor quality water?

• The water exists, but it is either contaminated or people must travel great distances to reach the water • WHO estimates that 80% of human illness results from insufficient water supplies and poor water quality caused by lack of sanitation

Briefly explain how a fecal coliform test is conducted. Why is the Petri dish incubated at a high temperature? Why is this a good test for the presence of untreated animal fecal waste?

• The water sample is forced through a filter, so microorganisms get caught on the filter • The filter is then blotted onto a Petri dish containing agar • The plate is incubated at 44.5 C, suppressing the growth of non-fecal bacteria • After 24 hours, you check for the presence of bacterial colonies (fecal bacteria) • E. coli bacteria only inhabit the intestines of warm-blooded animals, so this is a good test for the presence of untreated animal fecal waste

How far has the water table been lowered in some places? Why have many farmers stopped irrigating?

• This has lowered the water table more than 30 m (100 ft) in some places • This has made it too expensive too irrigate in many places, as deep drilling is costly

What are the 3 categories of water use and resource problems?

• Too much water • Too little water • Poor quality/contaminated water

What are some strategies for conserving outdoor water?

• Water lawn less often and for shorter periods of time • Don't use water to clean sidewalks • Don't wash car

What is water pollution? What are the different categories of water pollution?

• Water pollution = any physical or chemical change in water that adversely affects the health of humans and other organisms • 8 categories of water pollution: • Sewage • Disease-causing agents • Sediment pollution • Inorganic plant and algal nutrients • Organic compounds • Inorganic chemicals • Radioactive substances • Thermal pollution

Even though we have enough freshwater on the planet for everyone, what are two problems? What is stable runoff? What is an example of a place that has low stable runoff, even though the total runoff is high?

• it is unevenly distributed and some places lack stable runoff • Stable runoff = the share of runoff from precipitation that can be depended on every month • Stable runoff can be low, even though total runoff is high • Ex - India has a monsoon season during summer in which 90% of its rainfall occurs - most drains into rivers and is unavailable the rest of the year

What are the 3 main causes for lack of water? What is a drought? When did the severe drought in California begin?

•Drought •Overdrawing water for irrigation purposes •Aquifer depletion Drought = a prolonged period of lower than average rainfall • California has been in a severe drought since 2011 • In 2015 our reservoirs are only holding 54% of their historical average

What does inorganic mean? What are 2 types of inorganic plant and algal nutrients? What are 3 ways these nutrients get into water? What do these nutrients cause during an algal bloom?

•Inorganic = no carbon •Inorganic plant and algal nutrients include: • Phosphorus (often in the form of phosphate) • Nitrogen (often in the form of nitrate) • Both nitrates and phosphates come from fertilizers, atmospheric deposition, human/animal wastes • As already mentioned, inorganic nutrients can cause high BOD during algal blooms

What is saltwater intrusion? When and where does it occur? What does over pumping do to the water table and the saltwater layer?

•Overuse/overpumping of groundwater in coastal areas often results in a phenomenon called saltwater intrusion • In coastal areas, the fresh groundwater overlies salty groundwater • Pumping fresh groundwater from a well forms a cone of depression, which is an area around the well where the water table has dropped • As the water table drops (from overpumping), the saltwater migrates upward, intruding into the well and causing it to start pumping saltwater Excessive removal of groundwater lowers the water table and eventually empties an aquifer, eliminating it is a water source