Grade by Grade
A. Physical Patterns in a Changing World · Physical Patterns in a Changing World

Connected Systems: Challenging Environments, Natural Disasters and Human Responses

A3.11 A1.3 A1.1About 55 minutes
Learning goals
  • I can describe how landforms, climate, water and vegetation interact in a region.
  • I can assess which physical environments create the greatest challenges for people, using criteria.
  • I can describe ways people respond to natural hazards and disasters, and analyse short- and long-term effects of those responses.

Words to know

interaction
When two or more things affect each other, such as climate shaping vegetation and vegetation protecting soil.
natural hazard
A natural event that could harm people, such as an earthquake, flood, hurricane or wildfire.
natural disaster
A natural hazard that seriously harms people, property or communities.
criteria
The standards you use to judge or compare things.
levee
A raised bank built along a river to keep flood water in the channel.
dike
A wall of earth built to hold back the sea or a river.
floodway
A channel built to carry extra flood water around a town or city.
mitigation
Actions taken before a disaster to make its effects less serious.

Everything is connected

Geographers don't look at landforms, climate, water and vegetation one at a time forever. In real places, they interact. Change one, and the others change too. And together, they create both challenges and opportunities for the people who live there.

Interactions in two regions

Desert regions (like the Sahara):

  • Climate → very little rain, so vegetation is sparse.
  • Sparse vegetation leaves the ground bare, so wind can pick up sand and build dunes (a landform).
  • Rare, heavy rainstorms rush over bare ground and carve dry riverbeds and canyons.
  • Water is found at oases, where groundwater reaches the surface, so plants, and people, gather there.

Volcanic regions (like the islands of Indonesia):

  • Plate tectonics builds volcanic mountains.
  • Volcanic ash and rock weather into very fertile soil.
  • With a hot, wet tropical climate, that soil supports thick vegetation and productive farms on volcano slopes.
  • But the same volcanoes can erupt, so the environment is both an opportunity and a hazard.
Date palms surround a small pool of water in a hollow between tall orange sand dunes.
An oasis in the Sahara: groundwater reaches the surface here, so palms (and people) gather around it, while wind shapes the bare sand into dunes. AI-generated image

Which environments challenge people the most?

To assess (judge) which environments have the greatest impact on people, geographers use criteria, such as:

  1. Temperature extremes (very hot or very cold)
  2. Water (too little, or frequent floods)
  3. Natural hazards (earthquakes, volcanoes, hurricanes, tsunamis, wildfires)
  4. Landforms (steep slopes, high elevation)
  5. Growing season (can food be grown?)

People live in every kind of environment, often with deep knowledge of how to live well there. Using criteria helps us compare fairly instead of guessing.

CriterionSahara (hot desert)Canadian Arctic (polar)Ganges–Brahmaputra delta, Bangladesh (low-lying delta)
TemperatureVery hot daysVery cold, long wintersHot and humid
WaterVery littleLittle precipitation; lots of ice and sea iceToo much at times: river floods and storm surges
Natural hazardsDroughts, sandstormsBlizzards; thinning sea iceTropical cyclones, floods
LandformsDunes, rocky plateausTundra, rocky uplands, islandsVery flat and low, close to sea level
Growing seasonOnly near waterVery shortLong; very fertile soil
Using criteria to compare three challenging environments.

Natural hazards and disasters

A natural hazard becomes a natural disaster when it seriously harms people. The same earthquake can be a disaster in one place and cause little damage in another, depending on how many people live there, how buildings are made and how prepared people are.

Responses to hazards:

  • Earthquakes: building codes that require stronger, flexible buildings; strengthening older schools (British Columbia has a program to make schools safer in earthquakes); drills such as "Drop, Cover and Hold On".
  • Tsunamis: warning systems and evacuation routes. After the Indian Ocean tsunami on December 26, 2004, countries around the Indian Ocean set up a tsunami warning system.
  • Floods: dams, levees, dikes, floodways, and rules that stop building on floodplains. The Red River Floodway carries flood water around Winnipeg. After Hurricane Hazel flooded the Toronto area in 1954, many homes in river valleys were not rebuilt; much of that floodplain land became parks.
  • Wildfires: fire bans, firefighting, clearing brush near homes (FireSmart), and planned burns. Many First Nations have long used controlled burning to care for the land, and some communities are bringing this practice back.
  • Living with the sea: the Netherlands protects its land below sea level with dikes, pumps and huge storm barriers.
seadikepolder (farmland)sea levelland below sea levelside view, not to scale
A dike holds back the sea (blue) so that a polder (green farmland) below sea level stays dry. Not to scale.

Short-term and long-term effects of responses

Responses help, but they can have other effects too:

  • A levee protects one town now, but it can push flood water downstream to other places, and people may build more behind it, so a rare failure causes more damage later.
  • A dam controls floods and makes electricity, but it floods land and habitats upstream and changes the river.
  • Turning floodplains into parks means fewer homes are at risk, and it creates green space and wildlife habitat for the long term.

Geographers ask: Who benefits? Who might be harmed? What happens in 5 years, or 50?

Worked example

Let's analyse a response: the Red River Floodway

The Red River often floods in spring. In the 1960s, Manitoba built the Red River Floodway, a huge channel that carries extra water around Winnipeg. Analyse its short- and long-term effects.

  1. Challenge: Winnipeg is on a very flat plain where the Red River flows north. In spring, snow melts in the south first while the river downstream (north) can still be frozen, so water backs up and spreads over the flat land.
  2. Response: the floodway diverts part of the river around the city during floods.
  3. Short-term effects: during major floods, such as in 1997, the floodway helped protect most of Winnipeg from flooding.
  4. Long-term effects: it has been used many times and was expanded in the 2000s. But communities outside the protected area, including some First Nations and rural towns along the river, can still face serious flooding.
  5. Assess: the floodway is very effective for Winnipeg, but flood protection must consider everyone in the river basin.

The floodway is a successful response for Winnipeg in both the short and long term, but it does not protect everyone, so other communities need their own protection and planning.

WinnipegRed River flows northfloodway channelcarries extra wateraround the cityNSketch, not to scale
The Red River flows north through Winnipeg. In a flood, the floodway (dashed) takes part of the water around the east side of the city and returns it to the river downstream. Sketch, not to scale.
Hands-on activity

Build and test a flood barrier

You need: a baking pan, modelling clay or play dough, sand or soil, a cup of water, and a few small toy blocks or bottle caps as "houses". Do this outside (or on a tray you can empty outside, not down a drain).

  1. Shape a river valley in the sand with a channel down the middle. Put some "houses" close to the river and some on higher ground.
  2. Pour water slowly down the channel until it overflows. Which houses flood?
  3. Rebuild. This time, build levees of clay along part of the river. Pour again. What happens to the water at the end of the levees?
  4. Try a third way: move the houses off the floodplain and make it a "park".
  5. Compare the three tests. Which response worked best? Did any response push water somewhere else?

What to look for: your child notices that levees can send water downstream and that keeping homes off the floodplain is a long-term solution.

Just for fun

Riddle: I'm a giant ditch that sits empty most of the year, but in a big spring flood I become one of the busiest "rivers" in Manitoba. What am I?

The Red River Floodway!

Your turn

1

Explain one way climate and vegetation interact in a desert.

2

Why do many people farm on the slopes of volcanoes in Indonesia, even though volcanoes can erupt?

3

What is the difference between a natural hazard and a natural disaster?

4

List three criteria you could use to assess how challenging an environment is for people.

5

Name two ways people reduce the damage from earthquakes.

6

What does the Red River Floodway do?

7

How does a dike help the Netherlands?

More practice: warm-up

1

What is a levee?

2

Where is an oasis, and why are oases important in deserts?

3

In which year did Hurricane Hazel flood the Toronto area?

4

What is the earthquake safety drill called?

5

What is mitigation?

More practice: on your own

1

Use the criteria table to explain why the Ganges–Brahmaputra delta is both an opportunity and a challenge for people.

2

Why might the same strength of earthquake cause a disaster in one city but little damage in another?

3

Give one short-term and one long-term effect of building a levee.

4

Why do many experts think keeping homes off floodplains is a good long-term response?

5

Describe how landforms and water interact to make Winnipeg flood-prone.

Challenge

1

Use at least three criteria to assess whether the Sahara or the Canadian Arctic presents greater challenges to people. Give a reasoned conclusion.

2

A town wants to build a 3 m levee. Write two questions a geographer would ask before deciding.

3

Explain how climate change could make one natural hazard more frequent or severe in Canada.

Check your understanding

Quiz

1.

In a desert, sparse vegetation lets wind build...

2.

Why can soil near volcanoes be good for farming?

3.

A natural hazard becomes a natural disaster when...

4.

The Red River Floodway protects which city?

5.

A possible long-term problem with levees is that they can...

6.

Which is a criterion for assessing how challenging an environment is?

7.

A wall of earth that holds back the sea is a...

For parents and teachers

Big idea: This lesson connects A3.11 (how landforms, climate, water and vegetation interact in regions), A1.3 (assessing which physical environments have the greatest impact on people) and A1.1 (how people respond to challenges and opportunities, and the short- and long-term effects of those responses, such as dams, levees, dikes and earthquake-resistant buildings).

How to help: Check your family's emergency kit and plan together (Public Safety Canada's "Get Prepared" site has checklists). Look up your local conservation authority's floodplain maps. Discuss news of a natural hazard using the criteria and the "who benefits, who might be harmed" questions.

Common difficulties:

  • Thinking a hazard and a disaster are the same: preparation and building quality make a huge difference.
  • Seeing only one side of a response: encourage your child to name both short- and long-term effects.
  • Calling an environment "bad": stress that people live successfully in every environment, and many communities hold deep knowledge of their lands.

Sensitivity: disasters can upset some children, especially if your family has been affected by one. Focus on preparation and helpers. Safety: supervise water play in the activity.