Reach Up – Water Resources Module
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Dr. Mike O’Driscoll, Assistant
Professor, Geological Sciences
Mr. Shawn Thieme, Graduate
Assistant, Geological Sciences
Ms. Megan Ganak, Graduate
Assistant, Geological Sciences
Importance of Water
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It is essential for all life on this planet.
The human body consists of about 75% water
We drink and use water everyday.
We can survive 50-60 days without food, but only
2-3 days without water.
Hydrology
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is the study of the movement,
distribution, and quality of water
throughout the Earth.
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Why would someone want to become a
hydrologist?
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to helps us to better understand our
water supplies and provides insight for
environmental engineering, policy and
planning.
Great Job
Opportunities!!!
Environmental
Specialist
And Hydrologist
When it rains where
does the water go?
The Water Cycle
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Infiltration
The process by which water enters the soil surface
Infiltration
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Why study infiltration?
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If water does not infiltrate it usually drains quickly
to rivers.
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Rapid runoff to rivers can increase the likelihood
of flooding.
Runoff generation
When rainfall rate>infiltration capacity
Surface runoff or ponding occurs (overland flow)
Land-use effects on infiltration
Runoff occurs when
water cannot sink into the ground
What is the infiltration rate of asphalt or concrete?
Forested Soils
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Greatest infiltration rates
Organic litter at surface
 Root cavities
 Burrowing animals
 Earthworms
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Overland flow and flooding is
least likely
Asphalt ~ impermeable
(infiltration rate = 0)
Common
Example:
Wal-Mart
Parking Lot
Urban Land Use Effects on Hydrology
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Expansion of impervious surfaces.
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Runoff conveyed to channel by stormwater drains.
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More flooding.
W. Wright Rd.
Greenville, NC
Reedy Branch,
Greenville, NC
How Do Humans Change the
Water Cycle?
•US - impervious surface area/person (297m2) (Range 0-400 m2/ person )
•U.S. average 1.05% (Elvidge et al. 2007)
2.5
cubic meters per second
Total Discharge
2
1.5
Baseflow
Urban Stream
1
0.5
0
Feb-06
Apr-06
Jun-06
Aug-06
Oct-06
Nov-06
2.5
Total Discharge
cubic meters per second
2
1.5
Baseflow
Rural Stream
1
0.5
0
Dec-05
Feb-06
Apr-06
Jun-06
Aug-06
Oct-06
Dec-06
Urban
development
has caused
streams in
Greenville to
transport more
stormwater
By covering the land surface with
asphalt and buildings we can cause
more floods to occur
This is a serious problem in eastern
North Carolina because of the tropical
rainstorms in the fall
(hurricanes and tropical storms).
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Tropical storms may deliver several inches
of rain in an hour! If that water can’t sink
into the ground we experience flooding.
Flood examples from Hurricane Floyd, 1999Greenville (
)
source:USGS
Flood examples from Hurricane Floyd, 1999Greenville
Flood examples from Hurricane Floyd, 1999Greenville
Reach Up Project
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We’ll start today, looking at how
humans have altered the hydrology
in Greenville area, right on ECU
campus.
Let’s see how much humans have
changed the hydrology on ECU campus
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How has infiltration changed on ECU campus?
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The rate at which water enters the soil surface
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To test we will compare infiltration in forest areas
and campus sites where vegetation has been
removed.
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Hypothesis: When humans remove trees and
plants and compact the land surface, less water
can sink into the ground.
East Carolina University
Campus, Greenville, NC
You are here!
Soils
solid earth material that has been altered by
physical, chemical and biological processes
such that it can support rooted plant life
Soil Texture
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Relative proportions of sand, silt or clay
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Sand (0.063-2 mm)
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Silt (0.004 to 0.063 mm)
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Clay (<0.004mm)
Soil Texture
InfiltrationRainwater sinks into the soil
Water sinks into sand easily but takes a long time to sink into clay
because clay pores are very tiny. If soils are compacted their pores
become smaller and they allow less water to infiltrate.
Infiltration rate drops when vegetation is
removed and soil is compacted
The more land
is disturbed,
the less water
it can soak up
When less water sinks into the
ground, more water runs into rivers
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Urban development can increase
flood risk because less water flows
into the ground and more water
flows quickly to rivers
Infiltration comparison on ECU campus
30
25
Infiltration rate (mm/min)
Undisturbed site (Woods)
20
15
10
5
Disturbed site (Flanagan)
0
0
1
2
3
4
Tim e (m inutes)
5
6
7
8
Rules for Reach Up
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Be respectful to instructors and
your classmates.
Follow directions from the
instructors.
Raise your hand when you have a
question.
Don’t be afraid to ask a question.
Learn as much as you can.
Have fun!
What lurks in the forest?
Water sinks into forest soils about 4 times faster!
40
Infiltration
(mm/min)
Undisturbed sites
30
20
Disturbed sites
11.8
mm/min
10
3.4
mm/min
0
dist infiltration
undist infiltration
On campus mall soils were about 2.5 times more compacted than in forest!
1000
900
852 psi
Soil compaction
(psi)
800
700
600
500
400
341 psi
300
200
100
dist max
Disturbed sites
undist max
Undisturbed sites
Disturbed campus soils
Infitration rate = 3.4 mm/min
Soil compaction =852 psi
Increased risk of flooding
in areas where vegetation is
removed and soils compacted
Undisturbed forest soils
Infitration rate = 11.8 mm/min
Soil compaction =341 psi
Low risk of flooding
in areas with vegetation and
uncompacted soils
ECU should conserve and protect
these forested areas!
We learned that…
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Soil compaction and vegetation removal can affect
hydrology by…
Reducing the amount of rain water that can sink into the
ground.
These changes can make urban areas more flood-prone.
There are tools available to check where the floodplains
are in urban areas.
And finally…..
Hydrology is fun!!!!
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ECU camp helps students 'Reach Up' in science
By
ECU News Services and Greenville Daily Reflector
Sunday, July 19, 2009
A summer camp at East Carolina University uses hands-on experiments in biology, chemistry and
geology to help local African-American students develop an interest in science and science-related
careers.
Last week, a group of Reach Up campers studied soils at different locations on campus. With the
help of counselors and ECU faculty, the students used an infiltrometer to compare the rate of water
infiltration in areas used by humans to those in undisturbed land.
"We do these measurements to show how urban land use has changed hydrology," Mike
O'Driscoll, assistant professor of geology, said. "Through our findings, students can see how water
sinks through undisturbed areas a lot easier."
Twenty-four students in grades six through eight in Pitt County Schools are participating in the
three-week summer day camp, which continues through July 31.
The program is free to all participants, thanks to sponsorship by North Carolina GlaxoSmith Kline
Foundation Ribbon of Hope Program and ECU.
Six ECU students who major in chemistry, biology and geology serve as counselors and mentors
for the campers. ECU faculty members Andrew Morehead (chemistry), Anthony Overton (biology)
and Mike O'Driscoll (geology) supervise the laboratory activities for the middle school students.
Cheryl Treadwell, a science teacher at C.M. Eppes Middle School, assists participants with
designing science investigations. Rhea Miles, program director and an associate professor in the
College of Education, directs the program.
Reach Up is one of several camps hosted by ECU this summer.