Freshwater Systems
description
Transcript of Freshwater Systems
Freshwater Systems
• less than 1% of the water on Earth is available for us as freshwater
• freshwater exists as– surface water– groundwater
Surface Water
• lakes and ponds → standing water– in a pond sunlight
reaches the bottom– in a lake sunlight does
not reach the bottom• wetlands → areas
that are saturated with water
• rivers and streams → flowing water– speed, temperature,
clarity varies– more dissolved oxygen
than in standing water
Lakesnear shore, lots of plants
bottom-dwelling life that eats mainly waste from above
open water, affected by wind and currents
near surfa ce, lots of light & life
PROFUNDAL ZONEdeep & dark,
little life
Lake Succession
• sediments slowly fill in lake… and vegetation grows in from the sides
Rivers
• rivers are powerful forces… because they move they erode the land they flow over
• rivers can move vertically (cutting down) and horizontally (cutting sideways)
• rivers transport a lot of sediment with the water
• sometimes river channels get cutoff leaving an OXBOW LAKE
• old channels will eventually fill in like a lake
• rivers also dump tons of sediments into lakes and oceans
• sediments dropping out of suspension form deltas
Groundwater• most precipitation that falls on the Earth becomes
groundwater• groundwater sits just above bedrock
– the layer of saturated soil is called the WATER TABLE– the water table is closer to the surface in wet years… and
deeper from the surface in drier years• it is similar to a surface river system… except
underground• 25% of Albertans get their water from groundwater…
mainly for agriculture– when a well is drilled pressure forces groundwater to the surface
in the well• when groundwater gets heated up it often erupts to the
surface as a GEYSER
Run-off and Erosion• factors affecting run-off
– amount of precipitation & form (rain vs snow)– time it takes to fall/how fast it melts– slope of the land– type of soil– vegetation cover
• the movement of sediments from one place to another is called EROSION
• after sediments are transported they are deposited … this is called DEPOSITION
How can we reduce erosion?
Watersheds• the area of land that
drains into a body of water
• upstream areas or start of watershed is called HEADWATERS
• downstream areas or end of watershed is called OUTFLOW
Watershed Management• slow down water flow• keep vegetation on surface• protect river banks
– vegetation– rip rap
• direct water
Watershed Management
• control what goes into our waterways