APES

Chapter 9

Groundwater

water found beneath Earth’s surface

Zone of saturation

areas beneath Earth’s surfaces completely filled with water (mixed in with soil, rock)

Zone of saturation

areas beneath Earth’s surfaces completely filled with water (mixed in with soil, rock)

• Uppermost level of this is called water table

Aquifers

underground spaces and layers of soil and rock containing groundwater

• recharge/refill slowly - human development causes slower recharge

  • Ex. replacing vegetation/soil with impermeable surfaces like concrete, blacktop

Natural recharge

precipitation that filters down through soil and rock to replenish aquifer

Lateral recharge

water that moves sideways from rivers, lakes, and streams to recharge aquifer

Effects of over pumping aquifers

• Causes land subsidence: sand and rock of aquifer slowly collapse, compress

  • Land sinks, decreases in elevation

  • Can damage infrastructure, buildings

  • Future recharge of aquifer impossible as soil and rock compresses

  • Can also produce sinkholes: creators produced when subsidence occurs suddenly

Surface water

water that exists aboveground at Earth’s surface (ex. Rivers, lakes)

Surface runoff

precipitation/snowmelt that does not evaporate or soak into ground -> flows across the surface into lakes, rivers, etc.

Watershed (drainage basin)

area of land which drains to a particular body of water

Floodplain

region around surface body of water in which water overflows into

• Floodplains (including wetlands) provide flood and erosion control, purify water, recharge groundwater and soil

• Floodplains heavily populated, waterways altered

Channelization

make a river move a certain way by putting concrete along the edges, can lead to worse flooding

Dam

structure built across river to control water flow

Reservoir

body of water created behind dam

• Advantages/uses: can control flooding, produce electricity (hydroelectricity), can supply water for communities and agriculture, used for recreation

Irrigation

largest use of water in the world (70%)

Flood irrigation

water flows through unlined ditches (canals) through crop fields, absorbed into soil

• Large amount (~40%) of water wasted

Furrow irrigation

trenches/furrows dug alongside crops, filled with water

• ~30% of water wasted

Spray irrigation

uses sprinklers and pumps

• Often produces circular irrigated fields

• Only ~20% or less wasted

Drip irrigation

uses pipes with small holds to deliver water at or below surface

• More costly to set up but less than 10% of water wasted

Tiered pricing system (aka lifeline rates)

idea that governments can raise water prices

• Fixed amount of low-price water

• Charge more for additional water

Polyculture/agroforestry

growing crops among other types of crops/natural plants

• Reduces water loss, evaporation, and runoff; regenerates soil and prevents erosion

Xeriscaping

landscaping using drought tolerant native plants

Greywater

water from showers, sinks, laundry

• Not drinkable but can still be used for other purposes

What are the relative amounts of saltwater/freshwater on Earth?

<1% freshwater

~97% saltwater

Know the general process of the water cycle?

• Evaporation

• Condensation

• Precipitation

What are impermeable surfaces and how do they affect water cycle?

• Impermeable surfaces: water is unable to get through

• They don’t allow water to seep into the ground, resulting in slow recharge/refill of aquifers. More water is just sitting on the surface, flooding.

General facts about the Ogallala aquifer

• Located in central US

• Responsible for supplying water to important agricultural region

• Very slow to recharge (little rainfall

How does saltwater intrusion occur?

• Saltwater moves in as groundwater is extracted, contaminates groundwater

• Sea level rise can also contribute

How do humans make flooding worse, how can flooding be avoided?

• Humans make flooding worse by removing vegetation, destroying wetlands/floodplains, and causing climate change.

• Ways flooding can be avoided: preserve/restore natural state of wetlands/floodplains, replace impermeable surfaces, and address climate change

What are the positive and negative effects of floods?

• Positive: deposit sediment on land, recharge groundwater and wetlands

• Negative: can cause fatalities, cause billions of dollars in damage

What are the positive and negative effects of dams?

• Positive: control flooding, produce electricity, supply water for communities and agriculture, and used for recreation

• Negative: can displace people, destroy ecosystems, prevent river flow, and require large amounts of materials, money, and energy to build

General facts about Colorado River

• Begins from Rocky Mountain snowmelt

• Heavily dammed, water used for irrigation

• Supplies to dry southwestern cities

• Usually fails to reach mouth at Gulf of California

General facts about Thress Gorges Dam

• Yangtze river, China

• Provides huge amount of electricity

• Many ecosystems destroyed, millions of people displaces

What are general facts about California (ex. Central valley agriculture, less snow/ice in Sierras, less rainfall)?

• Salad bowl - grows food for salads

• Dry areas but grows plants that need a lot of water

General facts about Aral Sea

• Located in Kazakhstan

• Water diverted from Aral and feeder rivers for irrigation

• Has lost over 90% of its volume - split in 2 parts

How does water desalination work, pros and cons?

• It removes salts from ocean water or brackish water to make clean water

• Pro: fresh water

• Con: excess amounts of salt

What are relative proportions of human water use, how is water use hidden?

• 70% agriculture/irrigation crops

• 20% industry/manufacturing

• 10% communities/homes

how is water use hidden?

Hidden by growing raw materials for products, extraction, processing of natural resources, and manufacturing of products

How is water used in homes in the US?

Drinking, cleaning, toilets, laundry, and outdoor use

What are pros and cons of water privatization?

• Pros: work better and have more expertise than governments

• Cons: water is a public source, should not be in private hands, could drive up prices

What are some ways that water can be conserved in agriculture, industry, and homes?

• Irrigation at night, only water when necessary, organic farming techniques, grow plants based on climate, irrigate with treated waste water, rainwater harvesting, polyculture/agroforestry

What are pros and cons of polyculture/agroforestry?

• Pros: reduces water loss, evaporation, and runoff; 

• Cons: regenerates soil and prevents erosion

Short Answer 

1. Concentrated work in cities (urbanization) - This created less area for children and they became much more expensive to take care of and women had to start working multiple jobs, leaving less time for them to be with their children.

2. Birth Control pills - Women had access to birth control without prescription, leaving them able to wait longer to have children.

3. Improvement in infant mortality - Families no longer felt the need to have insurance babies, and just had the number of kids they wanted to have.

4. Television - Popular tv showers pictured families with less kids, influencing women to have less children because it was in "style".

5. Women's rights movement - There were very high levels of domestic violence and physical assaults on women, motivating women to stand up for their rights and fight for gender equality.