APES 5.10 Impacts of Urbanization

Enduring Understanding:

Learning Objective:

Essential Knowledge:

Urbanization can lead to depletion of resources and saltwater intrusion in the hydrologic cycle.
Urbanization, through the burning of fossil fuels and landfills, affects the carbon cycle by increasing the amount of carbon dioxide in the atmosphere.
Impervious surfaces are human-made structures – such as roads, buildings, sidewalks, and parking lots – that do not allow water to reach the soil, leading to flooding.
Urban sprawl is the change in population distribution from high population density areas to low density suburbs that spread into rural lands, leading to potential environmental problems.

Urbanization

The shift away from rural, agricultural based living into a human settlement with high population density
Doesn’t have to do with how many people there are, just the density
Jobs in these areas are not agricultural in nature
Lots of human constructions and infrastructure
The home is close to the workplace, medical and schooling resources, grocery and food needs, etc.
- These are either reasonably close by foot or by transit (public/personal)
- Public transit is good for the environment by moving more people with less energy
Space is used very efficiently, often building up instead of out

A lot of water is needed for so many people in one spot
- This often involves the diversion or disruption of normal water flow
- Anytime you disturb waterflow, you are altering habitats and affecting ecosystems
- Dams, in particular, affect both upstream and downstream
When an aquifer supplied by the ocean is drawn upon continuously, the freshwater is depleted and saltwater rises to replace it
- Eventually, salt water is being drawn up, which is unusable unless it goes through an intensive and expensive desalinization process

Water does not infiltrate through pavement/concrete
This means the water is not replenishing groundwater and runs off
- When water runs off, it also picks up anything on the ground and distributes that downstream
The water collects in a low point or runs into other bodies of water
It picks up the chemicals we use on our lawns, physical trash and debris, waste, etc.
From a climate perspective, the precipitation and water that deposits is not staying where it drops
- This destabilizes the local weather
The pollutants that water collects can also end up in drinking water
Heat islands can often occur due to these surfaces
- Surfaces like pavement have very low albedo, meaning they heat up very quickly by absorbing so much heat
- A lot of heat is taken in, stored, and them emenated throughout the day and night

Cities have a lot of electricity running through them, meaning fossil fuels are probably providing that energy
Lots of people means lots of waste, which needs to be disposed of
- Waste also releases greenhouse gasses

Eventually cities can no longer build upwards, or development doesn’t for certain reasons, so people settle further and further outwards
This creates suburbs
- This can create lower-density areas where personal car use is more common
- Which uses more fossil fuels, takes up more land, harms more habitats, more impermeable surfaces, etc.

Incorporating vegetation is a critical and wide-reaching solution
- Helps with habitat restoration, lowering heat, reducing some use of impermeable surfaces, recharge areas for groundwater, taking in carbon dioxide
Extending mass-transit
Permeable pavements have recently been invented and implemented
Urban planning sustainably and thoughtfully
Brownfields, or abandoned industrial constructs, can be torn down and productive replacements can be put in
A lot of these remediations also foster communities, improve human mental and physical health, and overall improve quality of life