Chapter 16: Surface Waters
Why are the Great Salt Lake and Dead Sea so salty?
They have inlets but no outlets. As a result, dissolved minerals are brought in and as the water evaporates from the surface, the mineral concentrations increase, thus making the lakes saltier.
What happen to most lakes in the natural course of events, over time?
They shrink
Why would an engineer design and build a levee?
To control flooding ( a levee is a wall along the channel of a river to contain the river to the channel )
What do we call a smaller stream that feeds a larger stream?
Tributary
What sort of naturally occuring geographic features can turn into a lake?
Volcanic Craders ( caldera ) Meteor Craters Sinkholes Basins
How can a low-gradient stream suddenly develop into a high-gradient stream?
When the low-gradient streams water flows over the edge of an eroded rock it can become a high-gradient stream. A good example is the Niagara Falls.
What are 3 possible sources for water that is found in a lake?
1) Flow in by an inlet stream 2) Precipitation 3) Underground Spring 4) Meltwater from Glaciers
Describe how a stream's rates of erosion and deposition are related to its gradient.
A high-gradient stream will have a higher erosion rate with a lower deposition rate, whereas a low-gradient stream will have a lower erosion rate with a higher deposition rate.
How would you describe the shape of a high-gradient stream?
A small V shaped stream. They tend to be fast flowing because they are V shaped.
What do we call water that flows either seasonally or continuously on a distinct course over land?
A stream
A stream along with all of its tributaries is called what?
A stream system
What is Eutrophication?
An increase of nutrients in a body of water. It causes "blooms" of algae and bacteria, reduces oxygen levels, increases turbidity, and can ultimately change what organisms can live in that water.
If you look at a topographic map and see a dotted blue line, what sort of stream is that indicating?
An intermittent stream ( a stream that is sometimes there and other times dry )
Explain how a stream's meander can move sideways across the land.
As erosion occurs more rapidly on one side of the meander, sediment deposition occurs on the inside of the bend, overtime moving the meander sideways. In short it moves sediment from one side to the other.
What do we call the lowest level to which a stream can erode?
Base Level
What are some advantages of building dams to produce hyrdroelectric energy?
Clean Energy ( doesn't pollute) Helps control flooding Store water for drinking or recreation Reduces soil erosion Kinetic and Potential energy to create electricity
A crosswise view of a stream
Cross Section
What geographical feature describes the are drained by a stream system?
Drainage Basin
The gradient of a stream relates to its what?
Elevation Profile
Broad, fertile, topsoil deposits from the flooding of a stream
Floodplain
Steepness of a stream's channel
Gradient
The measure of the slope of a stream is it's _____________?
Gradient ( High, Medium, and Low )
What do we call the origin of a stream?
Headwaters or Source
Which stream has rapids and waterfalls?
High-Gradient
Generally speaking, where can we find the greatest amount of the earth's fresh surface water?
In lakes and ponds
What is an Elevation Profile?
It is the description of how the stream changes from its beginning to end.
What is the worlds largest freshwater lake in volume?
Lake Baikal ( in Russia )
What is the worlds largest freshwater lake in area?
Lake Superior
Scientist who studies lakes
Limnologist
The study of lakes and freshwater systems
Limnology
Which gradient stream has floodplains?
Low-Gradient
These develop in the channels of low-gradient streams as they erode the sides of the riverbed.
Meanders
Why are floodplains good areas for farming?
The flood water bring minerals and nutrients to the soil. It replenishes the land for farmers to have better growing conditions with fertile topsoil deposits.
What is the lowest point to which a stream flows?
The mouth ( where it flows to a body of water )
What are some ways lakes can affect man?
Moderate Weather Provide Transportation Routes Used for Recreation Used for Agricultural Purposes Provides Drinking Water Provides Water for Power Production/Provides Water for Industry
What is a seiche?
Movements in a lake or pond which is like sloshing. This is caused by changes in air pressure due to weather. They can change surface height by up to several meters.
Do "older streams" have a high or low gradient?
Older streams have lower gradients as they have longer time to erode soils to base levels.
This is produced when a meander gets cut off from the main flow of a stream?
Oxbow Lake
