Sculpting Earth's Topography Lab Practical on Flash Flooding
pdf
keyboard_arrow_up
School
Arizona State University *
*We aren’t endorsed by this school
Course
111
Subject
Geography
Date
Feb 20, 2024
Type
Pages
5
Uploaded by PresidentUniverse10621
Unit 3 Sculpting Earth's Topography: Lab Practical on
Flash Flooding (2 points) Due
No due date
Points
2
Questions
4
Time Limit
None
Instructions
Attempt History
Attempt
Time
Score
LATEST
Attempt 1 (https://asu.instructure.com/courses/172892/quizzes/1298473/history?version=1)
7 minutes
1 out of 2
Score for this quiz: 1
out of 2
Submitted Jan 22 at 11:44am
This attempt took 7 minutes.
This lab practical relates to the lecture on "
In or Out (https://www.youtube.com/watch?v=1Csgc6adNaE%20https://www.youtube.com/watch?
v=wj7WnkgjhM0%20https://www.youtube.com/watch?v=MChe0ltPdzQ)
(https://www.youtube.com/watch?v=1Csgc6adNaE%20https://www.youtube.com/watch?
v=wj7WnkgjhM0%20https://www.youtube.com/watch?v=MChe0ltPdzQ)
where this video just shows an example of a flash flood. They key is whether precipitation sinks into the ground or runs off. In particular, this
question deals with the issue of materials with a low infiltration capacity (see slides 14, 17 and 19). Flash flooding occurs when the
surrounding drainage basin has a low infiltration capacity. This means that water can be shed quickly into the channel. Flash flooding tends to
happen more often in deserts and cities, but it can happen in any climate/vegetation with enough rainfall.
Certainly, the most important point of this lab practical is to make you aware of just how fast waters can flood stream or even a normally
dry desert wash. Sadly, there are lots of news stories about people who perished because they did not understand the basic science of flash
flooding. Simply read the questions and select the best answer.
0 / 0.5 pts
Question 1
This question relates to the lecture on fluvial
processes
(http://www.asu.edu/courses/gph111/BreezeLectures/29FluvialProcesses/29PublishFluvialProcesses/index.htm
-- whether precipitation sinks into the ground or runs off. In particular, this question deals with
the issue of materials with a low infiltration capacity (see slide 11). For the question, you will
need to watch a video about a flash flooding event captured in drone footage.
https
://
www
.
youtube
.com/watch?v=
MChe
0
ltPdzQ
(https://www.youtube.com/watch?v=MChe0ltPdzQ)
(https://www.youtube.com/watch?v=MChe0ltPdzQ)
In the study of rivers, a very common indicator that physical geographers measure is discharge
(Q). Discharge is the amount of water that moves past a given cross-section of a river per
second. The measurement in the USA is cubic feet per second. Width x depth x velocity allows
you to calculate discharge.
A good view of the flash flooding event can be seen when the floating log comes into view at
2:32 and the scene changes at 2:49. The distance traveled is about 75 feet. This gives you the
information you need to calculate velocity (ft/sec). The depth of flow was about 1.8 feet, and the width of the flow was approximately 26 feet.
What was the discharge of the flash flood (approximately) between 232 and 2:49
1920 f
/sec
You Answered
You Answered
You Answered
You Answered
2
3510 f
/sec
3
206 ft
/sec
Correct Answer
Correct Answer
Correct Answer
Correct Answer
3
3510 f
/sec
2
26 ft x 1.8 ft x 4.4 ft/sec = rounded to 206 ft
/sec
velocity is 4.4 ft/sec = 75 feet in 17 seconds = 75ft/17 seconds
3
0 / 0.5 pts
Question 2
For this question, you will need to watch a video about a flash flooding event captured in 2013.
Massive Flood Water in Vadi Fija Saudi Arabia
(https://www.youtube.com/watch?v=hi8D_jz31ls)
(https://www.youtube.com/watch?v=hi8D_jz31ls)
In the study of rivers, a very common indicator that physical geographers measure is discharge
(Q). Discharge is the amount of water that moves past a given cross-section of a river per
second. The measurement in Saudi Arabia is cubic meters per second. Width x depth x velocity
allows you to calculate discharge.
Please fill in the blank with the best answer. At the height of this flash flood, velocity of the flood
would have been _____________ with a width of 100 m, a depth of 4.5 m and a discharge of
1800 m /sec
3
4 m/sec
Correct Answer
Correct Answer
Correct Answer
Correct Answer
12 m/sec
12 ft/sec
8 m/sec
You Answered
You Answered
You Answered
You Answered
100 m x 4.5 m x 4 m/sec = 1800 m
/sec
3
0.5 / 0.5 pts
Question 3
For this question, you will need to watch a video about a flash flooding event captured in the
summer of 2011 in Australia.
Most amazing flash flooding footage ever
(https://www.youtube.com/watch?
v=cxAUoXTUtS8)
(https://www.youtube.com/watch?v=cxAUoXTUtS8)
As you watch the flood in progress, you can watch cars float away one-by-one. I hope that this
gives you pause before you yourself consider driving across a flooded roadway.
The topic here is how much running water does it take to make a SUV (sport utility vehicle) or
pick-up truck to float away.
Water weights 62.4 pounds per cubic foot. Given typical velocities of water running across
sloped roadways, for each foot the water rises, about 500 pounds of lateral force is applied and
the a typical vehicle volume displaces about 1500 pounds of water. This means that the car
weights 1500 pounds less for each foot the water rises.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
A typical pickup truck weighs about 5000 pounds, while a Suburban weights about
5500 pounds. A car like a Civic weighs about 3000 pounds.
QUESTION: what is the height of water needed to float a Civic (divide the weight
by 1500)?
About 2 feet of water
Correct!
Correct!
Correct!
Correct!
About 4 feet of water
About 0.5 feet of water
About 1500 feet of water
3000 divided by 1500 comes to 2. You should expect to see your car (and
perhaps your life) float down a river if you try to drive across in 2 feet of
water. If you drive a heavier SUV or pick-up, keep in mind that other forces
are coming into play to help float a vehicle away because there is a lot
more space underneath the vehicle to promote turbulence.
0.5 / 0.5 pts
Question 4
Watch
this video clip
(https://www.youtube.com/watch?v=y50dmIKvGic)
(https://www.youtube.com/watch?v=y50dmIKvGic)
and listen to the interview with the person who filmed it. The flash flood led to a
mudflow that trapped the individual being interviewed. In addition to the
thunderstorm, what key factor promoted the flash flooding that you watched?
A wildfire burn promoted the recorded flash flooding and mudflow.
Correct!
Correct!
Correct!
Correct!
A major water main leaked and generated the recorded flash flooding and mudflow.
Bare rock slopes generated the recorded flash flooding and mudflow.
A dam burst and generated the recorded flash flooding and mudflow.
The individual being interviewed was correct. After a fire, flash flooding
potentials jump. Fires decrease the infiltration capacity of slopes, shedding
water more efficiently. Quiz Score: 1
out of 2