Class Notes (905,607)
CA (538,462)
UTSC (32,636)
EESA07H3 (45)
Lecture

Lecture 5

5 Pages
161 Views

Department
Environmental Science
Course Code
EESA07H3
Professor
Tanzina Mohsin

This preview shows pages 1-2. Sign up to view the full 5 pages of the document.
Lecture 5: Lakes and Rivers
Rivers and Streams
Rivers are flowing bodies of waters on the surface of the earth that usually end at sea
Some simply define river as large stream, which flows in a channel
Rivers and streams are interchangeable
Streams flow in a channel and river in a large body
Stream is any body of running water that moves down slope under influence of gravity in a narrow and
defined channel on earths surface
Bottom of channel of river/stream is called the bed and sides of channel are called banks
Rivers generally start at source, like snow melt (such as glacier) or natural spring
Early course of river often in steep, mountain areas, which widens as surrounding terrain flattens out
Beginning of flow of river is steep and as it moves towards land it widens because the surface is flat
The Worlds Rivers
Can be categorized in terms of: length, flow, fame
5 great rivers in North America: Yukon, Mackenzie, Nelson, Mississippi, St. Lawrence
Yangtze River in China has history of flooding and many natural disasters (also known as sorrow of
Asia)
Know river figure for midterm
Rivers by length
oFirst 5: Nile, Amazon, Chang Jiang (Yangtze), Ob, Huang Ho (Yellow)
oFinal 3: Mississippi, Mekong, Niger
Rivers by flow
oAmazon, Congo, Yangtze, Ganges, Parana, Mississippi
oLowest is Murray (Darling) in Australia
Rivers by fame
oMackenzie: Canadas longest river
oMurray: longest in Australia
oColorado: river famous for Grand Canyon
oSt. Lawrence: links Greats Lakes with Atlantic Ocean
oMissouri: longest in U.S.
Residence time and fish population
oIn general, if residence time is lower, fish population will decline
oSometimes if residence time is higher, fish will die
Stream Flow
Streamflow = baseflow + interflow + runoff
Baseflow: composed of contributions from delayed interflow and groundwater runoff
Interflow: portion of streamflow contributed by infiltrated water
Losing stream: where stream levels are higher than surrounding watertable, so stream has potential to
lose water to aquifer
Gaining stream: stream levels are lower than surrounding watertable, so there is potential for
groundwater to discharge into stream channel
River Erosions and depositions
River and stream flow are very important agents of erosion and deposition- part of the global sediment
cycle
Flow associated with rivers and streams decides on deposits and landforms created on the landscape
www.notesolution.com
Flow velocities and channel patterns decide on shape on resulting landscape
Erosion is associated withmass wasting”
Sediment deposition is determined mainly by “stream energy” associated with velocity
If velocity is low, will get another type of landscape
Grand Canyon
oErosion of landfall
Niagara Falls
oHorseshoe shape created by erosion
Channel types
oMeandering: stream flowing left to right, mainly results of low velocities
oBraided: islands in between, results of high flow velocity
oFlow velocities are key
oHigh in catchment, velocities tend to be high leading to “braided stream
oSometimes braided streams turn into braided rivers when they are overflowed
oMost depositions of fine particles are in the inner loop of meandering
Inner loop has low flow zone and outer loop has high flow zone
Erosion occur on the outside of loop
Deltas
oForm at mouth of river, where the river meets the sea
oSome consider Deltas as compromise between flow velocity and action
oHigh- constructive: highly river dominated
oHigh-destructive: highly people dominated
Flooding
Flood: rising of body of water and its overflowing onto normally dry land. Occurs when rate of inflow
greater than rate of outflow
Rivers carry silt and clay
During natural flooding, sediments deposited on flanks of river floodplain
Ridges of sediment build up along floodplain, which limited lateral extent of flooding
Man-made causes of flood: construction of dams
Sea level rise
New Orleans
oGrown along the river
oMajor shipping centre on lower Mississippi River, is protected by levees
oRiver now stands 4 meters above downtown area
oLevees failed after Hurricane Katrina (2005)
oAlthough blame was on forecaster of hurricanes, William Gray, it was lack of emergency
preparedness that caused the damage
Why dams are built?
oGeneration of hydroelectric power
Subject to potential damage if reservoirs behind them are overfilled
There is tendency for managers to let water out of reservoir if it begins to get excessively
full
This result in conflict between hydroelectric and agricultural uses, results in flooding
oFlood control: cause problem when rainfall is heavy, water escape from reservoir, although dam
did not fail
oWater for irrigation
oRecreation
1996 Flooding at the Saguenay Valley, Quebec
www.notesolution.com

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
Lecture 5: Lakes and Rivers Rivers and Streams Rivers are flowing bodies of waters on the surface of the earth that usually end at sea Some simply define river as large stream, which flows in a channel Rivers and streams are interchangeable Streams flow in a channel and river in a large body Stream is any body of running water that moves down slope under influence of gravity in a narrow and defined channel on earths surface Bottom of channel of riverstream is called the bed and sides of channel are called banks Rivers generally start at source, like snow melt (such as glacier) or natural spring Early course of river often in steep, mountain areas, which widens as surrounding terrain flattens out Beginning of flow of river is steep and as it moves towards land it widens because the surface is flat The Worlds Rivers Can be categorized in terms of: length, flow, fame 5 great rivers in North America: Yukon, Mackenzie, Nelson, Mississippi, St. Lawrence Yangtze River in China has history of flooding and many natural disasters (also known as sorrow of Asia) Know river figure for midterm Rivers by length o First 5: Nile, Amazon, Chang Jiang (Yangtze), Ob, Huang Ho (Yellow) o Final 3: Mississippi, Mekong, Niger Rivers by flow o Amazon, Congo, Yangtze, Ganges, Parana, Mississippi o Lowest is Murray (Darling) in Australia Rivers by fame o Mackenzie: Canadas longest river o Murray: longest in Australia o Colorado: river famous for Grand Canyon o St. Lawrence: links Greats Lakes with Atlantic Ocean o Missouri: longest in U.S. Residence time and fish population o In general, if residence time is lower, fish population will decline o Sometimes if residence time is higher, fish will die Stream Flow Streamflow = baseflow + interflow + runoff Baseflow: composed of contributions from delayed interflow and groundwater runoff Interflow: portion of streamflow contributed by infiltrated water Losing stream: where stream levels are higher than surrounding watertable, so stream has potential to lose water to aquifer Gaining stream: stream levels are lower than surrounding watertable, so there is potential for groundwater to discharge into stream channel River Erosions and depositions River and stream flow are very important agents of erosion and deposition- part of the global sediment cycle Flow associated with rivers and streams decides on deposits and landforms created on the landscape www.notesolution.com
More Less
Unlock Document


Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit