D. Shell, SMHS 2017

Water Properties, Resources & Pollution

General notes about water (review from previous courses): 70% of Earth is covered in water

Water’s properties are a result of their hydrogen bonds (strong intermolecular forces) o Has a high boiling point & melting point (for covalent molecules) o Takes a lot of energy to change phases o Helps to keep animals cool (sweat)

High specific heat (amount of heat it holds) – water changes temp very slowly. o Moderates the earth’s climate o Protects living things from temperature fluctuations o Excellent coolant for power plants & car engines.

Known as the universal solvent b/c it dissolves most molecules

Adhesion – sticks to solid surfaces

The only substance that expands as it freezes instead of contracts. o Allows ice to float on top of lakes & animals to survive below. o Allows soil to form as rock breaks up (frost wedging)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I. Earth Systems and Resources (10-15%) C. Global Water Resources and Use

A. Freshwater/saltwater; a. 97% of water on Earth is salt water (found in oceans, seas & some lakes)

i. Salt water contains more than 3% by composition of salt (salt = ionic substances, not just NaCl) b. 3% of water is fresh water (found in some lakes, rivers, ponds, bogs, aquifers, creeks, etc)

i. 69% of this water is frozen in the arctic / in glaciers 1. Not available for human consumption 2. Removal would result in reduction of Albedo (reflection of sunlight back into the space)

ii. 30% in groundwater (water found under ground – in aquifers) iii. 0.9% is surface water (rivers, swamps, lakes, etc)

B. ocean circulation – water moves from one region of the Earth to another via 2 major circulation patterns a. Surface Water Currents (10%): Weather / surface water near the equator is warm; near the poles is cold. Cold water

moves towards warm water causing ocean currents. (Also fueled by winds formed b/c of air pressure differences) b. Density Currents (90%) (aka. Thermohaline Currents – THC) caused by differences in water temperature & salinity

i. Convection ocean circulation: cold water deep under the ocean moves upwards towards warm water. (Called an “upwelling” – also brings nutrients to the surface; good for plankton).

1. Salinity – closer to the equator = more saline b/c of evaporation. Salt water sinks. c. Human Caused problems: as global warming heats up the water…

i. Ocean circulation slows ii. Ice sheets melt

iii. Decrease in upwellings iv. Accelerated global warming – CO2 & CH4 released as ice melts

C. Agricultural: 70% of all freshwater is used to irrigate 16% of the world’s croplands (#1 use of water); runoff from farms causes eutrophication

D. Industrial: 20% of freshwater use – mainly used as coolants to keep machinery from overheating

E. Domestic: Used at homes / by cities – 10% of freshwater usage – includes what you use at your home, watering lawns, fountains, etc (flushing toilets = #1 use)

F. surface and groundwater issues; a. Surface Water: water found on land (rivers, lakes, ponds, bogs, swamps, creeks, etc)

i. Watershed / Drainage basin – large region of land from which water drains into the lowest point (lake, river, reservoir, etc)

1. Water ultimately flows into the ocean 2. Surface Runoff (problem) – precipitation that does not infiltrate the ground & percolate downwards or

evaporate back into the atmosphere runs downhill. a. Carries pollutants found on the ground to the rivers – fertilizer, chemicals that were spilled,

oil from cars, trash, etc. PAGE 1

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D. Shell, SMHS 2017

3. In the US: a. East of the Eastern Continental Divide (Appalachian mountains) flows into the Atlantic b. West of the Continental Divide (Rocky Mountains) flows into the Pacific Ocean c. In between the two Continental Divides – flows into the Mississippi River

i. Mississippi River basin – largest river basin in the US ii. Made of many river basins

iii. Dead Zone in the Gulf of Mexico at the end of the river because of pollution – mainly from agricultural runoff.

ii. Storm drain water often has trash / oil from improper oil changes or runoff from streets b. Groundwater: water found beneath the surface of the land.

i. Aquifers – porous water-saturated layers of sand, gravel, or bedrock through which groundwater flows 1. Source of water for humans, especially important in regions that have few surface water supplies 2. Largest in the US – Ogallala Aquifer (used to hold more water than all rivers, streams & lakes on Earth) 3. Aquifers divided into layers (See “Groundwater & The Water Cycle” activity) 4. Pros of using groundwater over surface water:

a. Is not lost by evaporation b. Usually is less expensive to develop than surface water systems (dams) c. Provide drinking water for ¼ of the world’s population (1/2 in the US)

5. Problems: a. Contamination (chemical from underground drums, leaching from above; microorganisms

from septic systems). b. Water table lowering c. Intrusion of salt water (occurs when aquifer is close to an ocean & water is being pulled out

too quickly) d. Subsidence (sink holes) occur when too much is removed e. Slow to recharge (takes a long time for water to reach the aquifer; subject to overuse without

enough rain to recharge). US withdraws 4-40 x its replacement rate f. Slow to recover from contamination – cold temperatures, lack of oxygen results in lack of

microorganisms that would decompose the contaminant. G. global problems;

a. In the US: i. most precipitation falls in the Eastern half of nation – energy production, manufacturing jobs, etc often set up in the

eastern US because of the abundant water 1. Problem: flooding, pollution, urban shortages (for domestic use) – lowering of lakes = habitat loss for

aquatic organisms, especially those living in ecotones ii. In the western US – most water is used for irrigation

1. Problem: low precipitation, high evaporation, droughts (may result in Dust Bowl conditions), depletion of aquifers, depletion of lakes – Mono Lake in California is almost dry because of use by Los Angeles

2. Solution – transfer water via pipes & aquaducts (very expensive) b. Rising Sea Levels:

i. Due to thermal expansions b/c of global warming (10oF change in Temp = 430’ rise in sea level) ii. Melting of ice – causes more liquid water in oceans & reduces albedo, increasing heat retention of water

iii. Other factors – land build up or erosion of mountains; plate tectonics; sedimentation, groundwater & oil extraction; changes in ocean currents & tides; distribution changes in the water cycle.

c. Causes of water Scarcity: i. Dry climate (due to long term weather patterns)

ii. Drought (21 days or longer in which precipitation is at least 70% lower & evaporation is higher than avg) 1. Often happens during summer months. 2. Cities put water restriction in place limiting irrigation, car washing, etc. 3. Often lead to famines – extreme scarcity of food (differ from other natural disaster b/c of the length of time

they last) 4. Worst on record: China (1958 – 1961) estimated 15-43 million died as a result

a. 6 of the 10 worst droughts in recorded history occurred in China & India iii. Desiccation – drying of soil because of deforestation & overgrazing. Result – hardpan iv. Water stress – low per capita availability of water caused by increasing numbers of people relying on limited levels of

runoff 1. 40% of world clashes are over water supplies (one of the causes of genocide in Darfur)

2. 500 million people in 34 nations are water stressed PAGE 2

D. Shell, SMHS 2017

The diagram on the left shows current levee systems that

eliminate flood plains for development. On the right it shows

smaller levees OUTSIDE of the existing flood plain (flood plain

helps soak up excess rain during floods and provides habitat)

d. Too much water: Floods i. Naturally caused by heavy rain & rapid melting of snow

ii. Floodplain – areas adjacent to normal channels of water (rivers, tributaries) 1. Provide natural flood & erosion control 2. Floods deposit rich silt for farming 3. Recharge groundwater & swamps around rivers 4. Ex: Charlotte’s Greenways

iii. Humans increase severity of flood damage by: 1. Removing water-absorbing vegetation (esp. On

hillsides) 2. Draining wetlands for development in floodplains

that absorb flood waters iv. Human attempts to minimize flood damage

1. Water Diversion: changing the course of water flow. Problems:

a. Decreased nutrient-rich sediment downstream decreases plant growth, decreases net primary productivity, disrupts food chains

b. Increased salinity as water volume decreases kills plants & animals c. Increased concentration of pollutants as water is not present to dilute – chemicals like arsenic

are toxic to plants & animals d. Decreased water volume in waterways downstream / below dams results in decreased

dissolved oxygen, increased water temperatures, decreased habitat, increases erosion e. Decreased water flow / flow rate leads to stagnation of water, contributes to lowering of DO

& increased water temperatures f. Increased water volume results in saturation (waterlogging) of soils results in lack of oxygen in

soil for plant growth 2. Channelization: section of stream is deepened, widened, or straightened to allow more rapid runoff

(worse for those downstream – increases erosion & flooding, loss of habitat, fewer nutrients downstream)

3. Artificial Levees – built along stream banks to reduce the chances of water overflowing into floodplains.

a. Failure causes big floods – most famous levee failures in US = New Orleans levees after Hurricane Katrina & in 1993, the Mississippi River flooded (2/3 of levees failed)

4. Arguments for diverting water to urban areas versus natural area

D. Shell, SMHS 2017

H. Conservation of water supplies a. Build dams & reservoirs to store runoff

i. Pros: 1. Areas subject to rainy season followed by dry seasons get more reliable water source from reservoirs. 2. Downstream flooding is reduced 3. Reservoir is useful for recreation & fishing 4. Provides water year-round for irrigation of cropland 5. Helps shallow water ways become navigable 6. Can produce cheap electricity (hydropower – reduces air pollution) 7. Stimulates local economy (job growth – construction, maintenance, operation)

ii. Cons: 1. Many dams in sequence can reduce the downstream flow to a trickle & prevent it from reaching the

ocean (Colorado, Ganges, & Indus Rivers) 2. Changes region’s ecosystem – reduction in native species 3. Enormous losses of water through evaporation 4. Mass of water behind the dam may cause small earthquakes 5. Flooded lands destroy forests or cropland & displaces people 6. Danger of collapse 7. Sedimentation behind the dam causes stress on the dam 8. Downstream cropland & estuaries are deprived of nutrient rich silt &

water (Japan has inflatable dams that can be removed easily to allow water to flow when necessary)

9. Migration & spawning of some fish are disrupted (some dams have “steps” along the side so fish can make their way over the dam) Cannon

10. Expensive to build 11. Methane production by biomass decomposing in reservoir causes global

warming 12. Release of mercury or other toxins from flooded soils 13. Increased risk of disease associated with reservoirs (Ex: Aswan Dam –

schistosomiasis) iii. Case Studies

1. Three Gorges Dam (China – Yangtze River) – largest dam in the world 1.6 miles long; 607’ high (5 x larger than Hoover Dam

a. Pros: Supplies power to 150 million people (same as 32 nuclear reactors – reduces dependence on coal) 225 GW of energy i. Holds back flood waters that have killed more than 500,000 people

b. Cons: Had to flood large areas of farmland, 140 towns, and 13 cities, displacing 2 million people & destroying architectural & cultural sites

2. Hoover Dam – largest dam in the US a. On the NV-AZ border near Las Vegas on Colorado River b. Lake Mead (behind the dam) – largest reservoir in US (supplies Las Vegas) c. Supplies enough energy for a town of 750,000 residents

3. Aswan High Dam (Egypt) a. Near Cairo on the Nile River b. Water is not traveling downstream – hurting farmland, residents c. Agriculture – poorly drained lands have led to soil saturation & salinization d. Increased diseases – especially schistosomiasis & malaria e. Fishing industry – has increased f. Erosion of delta – because of reduction of silt & sediment g. Evaporation is a bigger problem than expected = less water available

4. James Bay Project (Canada, 1970s) – Hydro-Quebec diverted rivers flowing into the James Bay flooding more than 4,000 square miles of tundra & coastal wetlands along the eastern shore of the Hudson Bay. The project consists of 600 dams, dikes & will block 19 large rivers. Adverse impacts: caribou were drowned while migrating; Hg poisoning of the Cree; coastal marshes & estuaries were degraded; salmon & other spawning fish died

b. Colorado River Basin – Diversion (large dams) has led to disputes between CA, AZ, & Mexico Page 4

Diagrams of different types of

dams

D. Shell, SMHS 2017

c. Better irrigation practices i. Microirrigation – drip irrigation (pipes on the ground have small holes that allow water to drip through – reduces

evaporation); trickle irrigation (pipes above the ground, but close, that allow small amounts of water to trickle little by little – allows water to infiltrate the ground, reducing evaporation & flooding)

ii. Irrigate at night / early morning when evaporation is low. Best time of day to use the sprinklers: iii. Monitor moisture levels – don’t irrigate unnecessarily. iv. Point sprinkler heads towards the ground to reduce evaporation

1. 7 problems associated with gravity flow:

d. GM crops require less water / choose crops for a region that are not water intensive i. Breed, develop, select crops that are drought resistant

e. Reduce runoff i. Level fields

ii. Contour planting, strip cropping, terracing, etc f. Increase soil content – organic material holds water g. Cover ground with mulch to reduce evaporation (done with recycled tires in some areas) h. Reduce meat consumption – more water is used in meat production than plant production alone i. Change in personal habits:

i. Reduce shower lengths / shower less frequently ii. Low flow shower heads and/or toilets

iii. Fix / replace leaky faucets / pipes iv. Better irrigation practices on lawns v. Turn off water when not necessary (while brushing teeth)

vi. Use water-efficient appliances vii. Reduce car washing at home – use a car wash service that recycles water

viii. Use gray water (water from sinks, rain barrels, etc) to water plants or put in toilets ix. Only run dishwasher / washing machine when full or handwash dishes. Don’t use dishwasher at all (use disposable

products j. Desalination (convert salt water to fresh water)

i. Distillation – boiling salt water to evaporate water (then condense); salt left behind ii. Reverse Osmosis – salt water is pumped at high pressure through a thin membrane w/ small holes that allow water

molecules to pass, but not salts iii. Used a lot in Africa & Middle East (especially oil producing nations)

1. Problem: Expensive; produces large quantities of waste water containing high levels of salts & minerals

IV. Land and Water Use (10-15%) C. Fishing A. overfishing;

a. China responsible for 1/3 of all fishing (human consumption, fish oil, fish meal, animal feed) b. Problem with “bycatch” – animals that are not targeted but are dredged up/caught in nets & die as a result of fishing c. Fisheries Management:

i. Regulate locations & # of fish farms; monitor pollution ii. Encourage production of herbivorous fish

iii. Label fish products as wild or fish farm (sustainable) iv. Set catch limits below sustainable yield (fishing seasons) v. Increase fees for harvesting from public waters (permits/license)

vi. REQUIRE the throwing back of bycatch vii. Monitor/destroy invasive species being transported accidentally

viii. Prevent importation from or place trading restriction on countries who don’t use sustainable fishing PAGE 5

D. Shell, SMHS 2017

B. aquaculture **See Unit 2 Notes C. Fishing techniques;

VI. Pollution (25-30%) C. Water pollution

A. Types; sources, causes, and effects;

Types Sources Causes Effects

Sewage

Fecal Coliform Bacteria Animal waste Ex: E. Coli

Runoff from animal farms Lowered dissolved oxygen (DO) / increased biological oxygen demand (BOD)

Disease-causing agents

Bacteria Typhoid Fever, Cholera, Dysentery, salmonella

Poor water quality Diarrhea, fever, dehydration, death

Viruses Hepatitis Can spread person-to-person Liver damage

Protozoa Cryptosporidium, amoebic dysentery

Parasites Diarrhea, fever, dehydration, death

Sediment Pollution construction sites, deforestation, etc

Silt runoff

Reduces photosynthesis by scattering light; destroys spawning grounds of benthic species; fills reservoirs; heats up water by absorbing sunlight

Inorganic Fertilizers & Chemicals

Farms, factories, coal burning power plants, salts from roads, sulfuric/nitric acid & Hg (rain)

N, P, K from farm runoff Acids, toxic metals (Pb, As, Hg), salts from roads

Damages human systems (causes cancer); harms aquatic life; Makes water nonpotable; hypoxia (reduced DO)

Organic Chemicals Gasoline, motor oil, plastics, pesticides, solvents, detergents, coolants, grease, tire residue, antifreeze

Leaks; industrial effluents, household cleaners, surface runoff from farms, yards & roads

Threatens human health & harms wildlife

Radioactive Substances Nuclear power plants, nuclear weapons, medical equipment

Illegal dumping Cancer in animals, mutations

Thermal Pollution Power plants, industrial plants that require cooling

Water is heated up Lowered DO b/c of evaporation; causes thermal shock in fish

Trash Animals ingest, decomposition

D. Shell, SMHS 2017

DO SAG

point of WASTE discharge

B. Two board categories of pollutants: a. Point Sources – the source of the pollution is easily identified, monitored; dumped directly into a water source b. Nonpoint Sources – indirectly placed in water; runoff from farmlands, etc; more difficult to control & monitor

C. Oil spills: worst ever – Deepwater Horizon (BP Oil Spill) in the Gulf of Mexico (4/20/2010 – 9/19/2010) = Estimates: 185-207

million gallons; other notables – Exxon Valdez (1989), a. Caused by: leaking oil rigs (Deepwater Horizon), tanker leaks (Exxon Valdez), slow leaks from cars on roads (runoff),

pipeline leaks, tapping into the oil glut to start flow, facilities, commercial dumping, truck spills

b. Problems: (environmental, economic, cultural) i. animals die (especially birds & marine mammals) due to lack of

insulation, ingestion, inhalation, suffocation, absorbing oil through skin, inability to fly

ii. Degradation of nurseries (estuaries), breeding grounds, habitat destruction

iii. Food webs disrupted (plankton, filter feeders) iv. Decreases photosynthesis v. Cost of cleanup

vi. Cost to local fishermen / tourism vii. Monetary loss of crude oil

c. Clean up: i. Physical: booms stop it from reaching shore; absorbents; burning; people

washing rocks; dredging/vacuuming ii. Chemical: dispersants (break large oil pockets into smaller droplets)

iii. Biological: microbes

D. cultural eutrophication: excess nutrients in the water (typically a natural process) Hypoxia = <1 ppm DO a. nitrogen & phosphorus runoff gets into water ways (usually from local farms – fertilizer & animal waste) b. N & P act as fertilizer for algae c. Algae grows out of control

i. As it competes algae dies & decomposes, removing DO from water ii. Algae covers the water blocking sunlight; photosynthesis can’t take place, resulting in a lack of oxygen

http://www.msnbc.msn.com/id/3032619/vp/49203207#49203207

d. Streams recover as water flows – oxygen gets trapped in the water as it flows over rocks e. Ponds often become swamps (stagnant water)

E. groundwater pollution;

a. Injection Wells: 60% of hazardous liquid waste solvents, heavy metals & radioactive materials injected directly into deep groundwater (EPA requires it to be deeper than water supply)

b. Pollution in an aquifer could remain for up to 1400 years c. Often comes from leaky underground storage tanks (i.e. gas stations, storage drums, landfills, etc) PAGE 7

D. Shell, SMHS 2017

F. maintaining water quality; a. Water quality testing to determine types & amount of pollution

i. pH (low pH = more acid); ii. Dissolved Oxygen (low DO = fewer animals);

iii. Biological Oxygen Demand (high BOD = fewer animals); iv. Temperature (High Temp results in less DO); v. Turbidity (high turbidity = more suspended particles);

vi. Heavy Metals (Pb, Hg, Cd, etc); vii. NO3

- & PO4-3(stream fertility increases results in algal bloom)

viii. Salinity, Cl, Odor (bad smell = decomposition), CH4 , CO2; ix. Pesticides x. Flow rate

b. Biodiversity Index used to determine types & numbers of species i. Large fish (trout, bass, etc) have a high BOD – first to die if there’s a problem

ii. Small organisms (worms, larvae, leeches, catfish, etc) have a lower BOD & can survive poor water quality

G. water purification; making water safe for human consumption a. Absorption – contaminants stick to the surface of granular or powdered activated coal b. Disinfection – Cl, O3 or UV radiation kills bacteria c. Filtration – removes clay, silt, organic matter, precipitants from treatment process d. Ion exchange – removes inorganic compounds

https://www.yahoo.com/katiecouric/the-flint-water-crisis-explained-031412993.html

H. sewage treatment/septic systems

a. Municipal waste water treatment (waste water treatment plant –WWTP) – involves physical, biological & chemical removal of contaminants (trash, sewage, nutrients, etc) from water. Influent (waste water that enters the system) goes through the following process..... i. Phase 1: Primary Treatment (Physical removal of debris)

1. Bar screen (or filters, nets, etc) to remove large solid material (branches, rocks, gravel, trash, toys, remote controls, etc). Screen catches the materials, dumps them into a dumpster, goes to a landfill.

2. Primary Settling (aka sedimentation, detritor, or sand catcher) tank – water sits in tanks allowing sand, grit, feces, small debris to settle to the bottom (called sludge). a. Sludge is dried. Goes to a landfill, is incinerated, or applied to crops (not done often b/c of contamination)

ii. Phase 2: Secondary Treatment (Biological process)

1. Aeration – bacteria is placed in tanks which digest the fecal matter, soaps, food waste, pathogens (i.e. E Coli) that was too small to settle out during primary settling. a. Aeration tanks are pumped with oxygen to

allow proper decomposition b. pH must be monitored c. risk of bacteria dying because of anti-bacterial

soaps/detergents 2. Secondary sedimentation – water from aeration

tanks (along with bacteria) move into a tank without excess oxygen. Bacteria floc together, sink to the bottom of the tank, and are pumped back to the aeration tanks.

iii. Phase 3: Tertiary Treatment (Chemical) 1. Disinfection – kills pathogens (any bacteria that

didn’t settle: E. Coli, coliform bacteria, pathogens, cholera, viruses) using ozone, uv light, or chlorine.

2. Phosphate removal - using lime, alum, etc Nitrate / ammonia removal – denitrifying bacteria (anaerobic microbial digester) PAGE 8

D. Shell, SMHS 2017

iv. Effluent is dumped into tributaries v. Some cities have water treatment plants attached to waste water treatment plants – effluent goes straight to the

disinfection/cleaning process to return to homes. vi. Entire process takes a few days, but can be sped up if necessary.

vii. From your flush to your faucet takes about 30 days.

b. Septic Tanks – used in rural areas where municipal treatment is not available. i. Must be maintained by the home / business owner

ii. Tank in the ground where water from the home goes iii. Must add bacteria to encourage decomposition

I. Clean Water Act and other relevant laws)

a. Clean Water Act (AKA – Water Pollution Control Act 1972, 1977, 1987)

regulate the discharge of pollutants into U.S. waterways • attain water quality levels that make these waterways safe to fish and/or swim in • restore and maintain the chemical, physical, and biological integrity of the nation.s water • set water quality standards to limit pollutants • require states and tribes to complete an assessment of all state rivers impacted, or potentially impacted, by non-point pollution (Section 319) • reduce polluted runoff from urban areas and animal feeding operations (Section 319) • provide enforcement mechanisms (e.g. civil actions/criminal penalties) to ensure compliance • develop management plans to address problems • establish ongoing monitoring of local waterways • require discharge permits for effluent emissions • provide financial assistance to fund improvements/education/training • prevent habitat destruction • establish best practical control technology (BPT) to reduce pollution • establish best available, economic achievable technology (BAT) to reduce toxics • establish best management practices (BMPs) to reduce pollution.

b. Laws to monitor sewage: i. Water Pollution Control Act (1956)

ii. National Environmental Policy Act (1969) iii. Safe Drinking Water Act (1974, 1996): sets standards for how much of various pollutants can be in water.

c. Laws to monitor fish harvesting:

i. Endangered Species Act ii. Marine Mammal Protection Act

iii. CITES Treaty iv. International Whaling Commission – regulates the species that can be harvested, sets quotas on the number of

whales that can be harvested

d. Ocean Dumping Ban Act (US - 1988) - makes it illegal to dump trash in the ocean

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