Freshwater Systems

Lakes & Ponds

• Both are large holes filled with standing or still water
• A pond is shallow and/ or clear enough to allow sunlight to reach the bottom
• This will result in rooted plants throughout the pond
• A lake does not allow sunlight to reach the bottom either due to depth or to clarity
• There may be rooted plants along shoreline but not in the middle of the lake.

Barrier Lake – Kananaskis

This lake is created by Barrier Dam that is one of several dams along the Kananaskis River.

Glacial dust suspended in the water makes it look bluish green.

Pond

Notice how you can see all the way to the bottom!

There are grasses and other rooted plants growing along the bottom.

WETLANDS!

• Usually formed by a depression in the land that causes it to sink below the water table.
• Soil is spongy and absorbs water very well.
• Wetlands are important in preventing against flood damage and for filtering toxins out of groundwater.

MARSH

• Often bordered by grassy meadows and stands of trees and shrubs.
• Water source is mostly run-off and precipitation but groundwater often feeds marshes.
• In Alberta, marshes are also called SLOUGHS

Bow River Marsh area. Close to Banff Alberta.

BOG

• Formed where glaciers have left a depression in the land
• Lots of PEAT (partially decomposed organic matter)
• High water tables and usually slightly acidic
• Water source is primarily precipitation
• Water is stagnant (unmoving) so they are often smelly!
• formed in cool, wet areas where drainage is poor and the soil lacks oxygen.

SWAMP

• Forested wetlands
• Flooded seasonally by standing or slow moving water.
• not common in Alberta
• Many wetlands are incorrectly referred to as swamps.

FEN

• Resemble bogs in peat composition
• Because they are fed by groundwater, soil is not as acidic.
• Support marsh-like vegetation

Rivers and Streams

• Moving bodies of water.
• As they start out in the mountains, they are cold and fast moving – this makes them high in oxygen.
• Rocks and pebbles are eroded into smooth, round shapes.
• Sediments are deposited as rivers and streams start to lose energy.
• Contain pools and riffles

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Groundwater

• Very important source of freshwater.
• Water moves through pores and cracks in rocks via PERCOLATION
• Once it reaches the impermeable bedrock it cannot go further.
• Water backs up and forms an AQUIFER
• The layer of groundwater at which all pores are full is called the WATER TABLE

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Watersheds

Another name for a DRAINAGE BASIN

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An area of land that drains into a body of water.

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There can be smaller watersheds within larger watersheds

Canada’s Watersheds

Alberta’s Watersheds

Alberta is unique because at least 3 of Canada’s watersheds converge in one province!

Landforms and Watersheds

Landforms will determine:

• The size of a watershed
• Speed of water flow within a watershed
• Direction of water flow

Upstream areas of watersheds are called the HEADWATERS

The end point of the watershed is called the OUTFLOW

RUN-OFF

• Any water that does not evaporate or soak into the ground is called run-off
• Run-off can cause erosion of soil and change drainage patterns.
• Run-off patterns can be changed by
• paving over land (pavement doesn’t absorb water)
• logging (tree and plant roots reduce run-off by soaking up water)

Runoff and Erosion

Four Factors that can affect the amount of runoff in an area:�1. Amount of rainfall – large increases in rainfall can increase runoff

2. Time it takes rain to fall – large amount in shorter time can increase runoff because it doesn’t have time to soak into the ground

3. Slope of the land – steep slopes will increase runoff while gentle slopes descrease.

4. Amount of vegetation – plant and tree roots absorb water so decrease runoff

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River Flow Monitoring

Streamflow: Amount of water discharged by a watershed

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This information helps scientists:

• Analyze water quality and quantity accurately
• Warn about floods
• Predict drought conditions
• Design irrigation systems

Three ways an eroded river can be restored:

1. Plant native vegetation along its banks to stabilize the soil
2. Reinforce banks of rivers with logs or rip-rap baskets
3. Digger logs – make artificial rapids which increase oxygen content and deepen rivers

Material that has been eroded upriver where currents are strong, gets deposited as the land levels off, the river slows down and loses energy.

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Sediments

• The greater the river’s flow rate, the more energy it has to carry sediments
• Sediments can carry pollutants downstream
• Sediments are classified as:
• Suspended in water
• Rolling/ bouncing along the bottom
• Stationary

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What do each of these classifications tell us about the river’s energy?

If too much sediment is built up at a river mouth (or OUTFLOW) then dredging may have to occur.

Groundwater Contamination

Because groundwater flows underground and makes its way to surface water, contamination in one area can cause problems over a wide-spread area

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There are 2 kinds of contamination sources:

1. Point Source: small, defined area

Example: leaking gas can, local spills

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2. Non-Point Source: wide, undefineable area Example: run-off from farmers’ fields

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The Water Dilemma

Remember that Southern Alberta tends to be dry and drought-ridden while Northern Alberta tends to risk flooding.

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Dams are often built as an attempt to control the flow of water through river systems but their impact on the surrounding environment is substantial

Predicting Floods: Page 409

Work with a partner and examine the two graphs on page 409. Answer the two questions (What Did You Find Out) in complete sentences and turn them in by next class. You will be marked on how well you use the evidence in the graphs to support your answers.