APES- Unit 2- Water

Why is water scarcity becoming more common?

- Population growth
- Wasteful use of water resources
- Climate change

Diversion

Using technology or engineering to move water from one location to another, often against natural processes

Conservation

Using existing freshwater sources efficiently to make the supply last longer

Aqueducts

Manmade canals to transport water from one place to the next, common in western US

Form of diversion

Problems of dams

- Floods upstream (displaces people ad land loss)
- Water lost from eveporation
- Dam blocks sediment
- Water qualities in reservoir change (deeper, colder, stagnant, clearer)

Dams

Placed on rivers to control water fow downstream, generate electricity, collect water for irrigation and drinking, recreation

Form of diversion

Levees

Wall built around water resources to prevent flooding, usually on floodplains

Form of diversion

Problems of levees

Floods adjacent land, can flood other cities with lower levees

River channelization

Manual deepening or straightening of a river (river flows faster)

Form of diversion

What happens in area where a river is flowing quickly?

sediments are taken away and carried, causes erosion

What is an oxbow lake and how does it form?

A river curves so much it runs into each other, the river takes the straighter route and cuts off most of the curve which turns into an oxbow lake and slowy dries up

How do you deepen a river?

Dredging- digging up the bottom to deepen it. Dredging causes more erosion from faster moving water and unstable banks

Where is the best place to put manmade river enbankments/levees?

Set back from the river for green space, this gives space in case of a flood to prevent river flow

What are consequenses of narrow levees (right up to the river bank)?

- Increase in flooding downstream
- Increased risk of flooding if flood surpasses levee

Central Arizona Project

- Diversion of Colorado River
- Aqueducts made to move water uphill to large cities
- Critical for populations and farming (Arizona is a desert)

Cloud seeding

- Silver iodide or dry ice sprayed from planes in the air to create bigger and heavier raindrops and cuase rain
- Does not create rain- just increases liklihood

James Bay Project

- Canadian project, one river completely rerouted to increase water volume in new river area
- Dams built on the river, more electricity generated
- Huge change in the river habitats, some organisms could not adjust

California Water Project

- System of aqueducts to distribute water
- Water taken from the North and moved to the South (area of more water -> area of higher population)
- Open aqueducts (evaporation) over 400 miles long sometimes
- Need for water to be moved uphill in some areas

Hoover Dam

- First major dam, on the Colorado
- Resevior is Lake Mead
- Controls downstream flooding, irrigation and drinking water
- Inspired many more US dams

Desalination

- Creating freshwater by forcing salt water through filters under high pressure, separating water from salt
- Requires a lot of energy, expensive and uses fossil fuels
- Common in Middle East (Saudi Arabia, UAE) because of low water supply but high oil supply

Three Gorges Dam

- Biggest dam on Earth
- At confluence of multiple rivers, duilt downstream from them to utilize the water
- Proposed to produce 10% of China's energy (But very muddy, some think it might just turn into a mud pit instead of producing energy)
- Displaced millions of people as the reservoir fills up

Iceberg towing

- Process of towing frozen freshwater from a larger iceberg to a place that needs water and then melting it to use

Aral sea

- Used to be the 4th largest freshwater lake in the world (Located in central Asia)
- Farmers started using the water and diverting the water for crop irrigation
- Along with evaporation and droughts, the water level has gone down by over 90%
- Ecosystem has had an increase in salinity, loss of organism, habitat loss, reduced crop yields from less water, exposure to pollutants that used to be at the lake bottom

Mono lake

- California lake, outside major cities that have high water demands
- Cities diverted water from the lake and drained it over 50%
- Rights to use lake water now revoked to let the lake (slowly) start to refill

Decomposting toilets

Disposal system that uses no water to break down waste, waste broken down by bacteria over time

Drip irrigation

Watering crops by slowly feecing water directly to the plant roots via piping next to the plant

Greywater system

Taking water that was used in one application (not toilet or kitchen water, risk of contamination) and slightly dirty and using it for another (ex. shower water-> garden water)

Low flow appliances

Slowers or toilets that use less water to perform their function compared to older models

Rain barrels

Catching water from rooftops during raindalls into containers for other uses, like watering gardens

Xeriscaping

In dry climates, using vegetation adated to those conditions on your lawn to reduce need to watering plants (like succulents and cacti)

Flood irrigation

Filling an entire field with water, about 20% water loss from runoff and evaporation, risk of waterlogging

Furrow irrigation

Cutting small channels in the soil between crop rows and filling with water. About 33% water loss from evaporation an runoff.

Spray irrigation

Pumping groundwater and applying water through nozzles over a field, about 25% water loss from evaporation and runoff.

Point source

When pollution is originating from a single, identifiable source (ex. a pipe draining sewage into a lake)

Nonpoint source

Pollution that is scattered and afflicting a larger area, nontraceable (ex. runoff from a farm, a large area of land)

What is the biggest polluter?

Farmers and agriculture

What nutrients pollute?

Nitrogen, Phosphorus, Potassium (often in form of potash)- N-P-K in fertilizers

How does nutrient pollution affect water?

Causes algae blooms, which then die and are decomposed by bacteria which use oxygen, and oxygen levels decrease, organisms who need this dissolved oxygen die

What is the process of oxygen levels decreasing from nutruent pollution called?

Cultural eutrophication

What is BOD?

Biologial oxygen demand, measured by scientists and tells how much stuff in the water could be eaten or decomposed by bacteria.

What does a high BOD indicate?

That there will soon a be a high oxygen demand which indiates that there is some kind of decomposable waste in the water.

What is a dead/hypoxic zone?

An area of water where there is no more dissolved oxygen, after a Harmful Algae Bloom/Red Tide. Some can give off harmful toxins.

What is a watershed?

An area of land that drains water to the same location.

What is an aquifier?

Wet, inundated rock layers in the earth (water under the surface)

What is an unconfined aquifier?

An aquifier with a permeable layer of soil above it, water can easily enter from above

What is a confined/artisan aquifier?

An aquifier stuck between two impermeable rock layers

What is the water table?

The upper level of water in the soil, level changes with climate/conditions

What is a spring?

Where water fows out of an aquifier onto Earth's surface

What is a well?

A hole drilled by humans into the earth to access groundwater

What is recharge?

Aquifiers refilling from percolation

What is a cone of depression?

Water table lowering as a result of a overused well, pulling the water table into a cone shape towards the well

What is the world's largest aquifier?

Ogalalla aquifier (Mid-US)

What is saltwater intrusion?

When satwater gets into a freshwater well (will make it unusable)

What are causes of saltwater intrusion?

- Rising sea level
- Well overuse/overdrawing- freshwater is less dense but a cone of depression will draw the saltwater to the well

What is the best way to prevent groundwater pollution?

Seal old wells when they are not in use (they go directly to the groundwater so it is easy to pollute through them)

What three things are needed to classify an area as a wetland?

- Hydrophylic plants (plannts that like water)
- Hydric soils (soils that indicate wet conditions, like gray color from low oxygen)
- Soil that is covered or saturated with later for all/part of the year

Why are wetlands important?

- Absorb water (prevents flooding)
- Filter water (can absorb polluttants, water perlocates slowly)
- Coastal storm protection
- Provide habitats and food
- Recreational areas (hhelps economy)
- Stores carbon

How do wetlands get degraded?

- Draining
- Filling
- Pollution and dumping
- Water diversion
- Invasive species
- Climate change
- Dredging and channelization

What is mitigation?

When you develop on a wetland, you have to make a new one somewhere else so you don't lose the net weetland area. Not very successful.

What is evaporation?

liquid water (on land) -> air

What is infiltration/perlocation?

liquid water ON land -> liquid water IN land

What is precipitation?

Water in the air -> liquid water on land (rain)

What is runoff?

Liquid water on land -> Liquid water in a bod of water (high -> low elevation)

What is transpiration?

Water from plamts -> water in the air

How much of Earth's water is freshwater?

2%

How much of Earth's freshwater is liquid?

13%

Where is most of Earth's liquid freshwater?

In the ground (groundwater)

What is most water used for?

Agriculture (~70%)

What are buffer strips?

Physical land boundaries to control and manage water

Where is most oil pollution from?

Runoff

How can you physically control and clean oil spills?

Skimming, booms, absorbing

How can you chemically clean oil spills?

Burning (releases toxic gasses), spraying dispersants

How can you biologicaly clean oil spills?

Oil-eating bacteria

What/When was the Exxon Valdez spill?

- 1989 oil spill
- Operating error in Alaska
- 11-25 million galons spilled
- Very damaging to wildlife and food chain

What/When was Deepwater Horizon?

- 2010 BP oil spill
- Largest spill ever in Gulf of Mexico
- Lots of dispersants used
- up to 4 million gallon/day spilled, leaking for 3 months

What are the effects of sediment pollution?

Lowers clarity, blocks sunlight, clogs fish gills

What are the effects of hot water pollution?

Lowers holding capacity of dissolved oxygen, can kill organisms not meant for hot water

What is stormwater?

Runoff and precipitation that is NOT caught or cleaned. Percolates and drains into water sources- or will sit on impervious surfaces if given no other choice.

What is wastewater?

Water that us used and then collected to be cleaned at a water treatement plant.

What is the traditional solution to stormwater?

Storm drains to relocate the water from impervious surfaces

What is a better way to decrease storm water?

Low impact design- things designed to increase percolation and decrease runoff as well as reducing pollutant load in runoff (ex. rain gardens, rain barrels, greenroofs)

What are the steps of wastewater treatment?

Primary, secondary, tertiary, disinfection, disposal

What does the primary phase of wastewater treatment do?

Physical decontamination (bar screens) and then a primary settling tank to remove all to most solids

What does the secondary phase of wastewater treatment do?

Biological removal of contaminants- heating and aerating water to encourage bacterial activity to consume what organic materials they can, and then a secondary settling tank period to collect the bacteria

What does the tertiary phase of water do?

It's expensive so not done much but it adds chemicals to the water (chlorine, ozone, or UV light) to remove everything else in the water like dissolved nonorganic chemicals

How is wastewater collected and treated in rural areas?

Septic systems- wastewater goes to a septic tank that then either degrades in the tank or sent out to a leachfield to percolate

What US legislation for water pollution was signed in 1972?

Clean Water Act, created water quality standards

What US legislation for water pollution was signed in 1974?

Safe Drinking Water Act, set new standards for drinking water