Chapter 5: Running Water and Ground Water Flashcards
(41 cards)
The process of the Hydrologic Cycle?
Precipitation Evaporation Infiltration Runoff Transportation
(this cycle illustates the unending circulation of Earth’s water supply)
What is a Drainage Basin?
specific land area that contributes water to a river system
a Divide separates separate drainage basins.
The beginning of water being added to the surface is called what?
Streamflow
Stream flow begins as moving what?
Sheet wash:
thin surface layer of water
moves down steepest slope
erodes substrate
What creates tiny rill channels when forming streams?
sheet wash erosion
Rills the deepen and down cut into channels
The three factors to determine water velocity
1) Gradient/ slope of channel (vertical drop of steam over distance)
2) Channel characteristics (shape, size, roughness of channel bed)
3) Stream discharge (volume of water flowing in stream)
What is the Stream Longitudial Profile?
Cross-sectional view of stream across landscape.
It is a smooth curve.
Gradient decreases from the head to the mouth.
The two factors that increase downstream?
Discharge- volume of water in stream increases
Channel size- width changes from narrow to wide
The two factors that decrease downstream?
Gradient (slope)- channel becomes less steep
Channel roughness- channel smooths out
When the sediment is deposited in the opposite bank, it is called what?
point bar
When fast water erodes one stream bank is called what?
cut bank
The most common natural hazard _____.
Floods
Three causes to flooding?
1) Weather.
heavy rainfall/ rapid snow melt/ several days of rain
2) Human interference.
interference w/ stream system
3) Ground too dry to adsorb participation.
runs over land instead of infiltrating/ can result in flash flooding
Missouri and Mississippi Rivers near St. Louis facts
*Regional flooding last for 70 days!
*50 people died
*Property loss was over $27 billion
Normal Stage: 1988
Flood Stage: 1993
Big Thompson River Flood of 1976, Estes Park, Colorado facts
- Within 4 hrs 12 inches fell
- Rock and soil stripped away and added to the flow
- Wall of water was 20 ft deep in 30 min
- Houses, bridges, roads, and people vanished.
- At least 144 peoples died
The two efforts of flood control?
1) Engineering efforts to reduce flooding
2) Non-structural approach through sound floodplain management
The engineering efforts to reduce flooding?
Artificial Levees: earthen mounds built on river banks to increase the volume of water the channel can hold
Flood-control Dams: built to store floodwater and then let it out slowly
Channelization” altering stream channel in order to spread the flow of water to prevent from reaching flood height
What is one flood-controlled dam?
Hoover Dam
built in 1931 - 1936
What running water “work” streams involves what?
1) Erosion
2) Transportation
What is running water stream load?
An amount of transported material carried by the stream
Three types of stream load?
1) Dissolved load: ions from weathering of minerals
2) Suspended load: fine particles (slit or clay) in the flow
3) Bed load: larger particles roll, slide, and bounce along stream bed
Transportation - Depositional features include…
Deltas- exist at mouth of stream that enters ocean or lake. Form when sediment from a stream, drops out due to lock of water velocity.
Natural Levees- form parallel to the stream channel due to flooding along stream bank.
What are stream deposited sediments?
Deposits are known as alluvium
They are well-sorted deposits
Sediment deposition is caused by what?
A decrease in velocity
