The Hydrologic/Water Cycle
Chapter 13, p. 432-433
News: http://www.downtoearth.org.in/news/-36-cities-to-face-water-crisis-by-2050--59955
Life needs water!
You require 3L of
water a day to
maintain essential
fluids of the body
maintaining a
healthy water supply
is vital
Hydrosphere has about 326
million cubic miles of water!
https://mediaplayer.
pearsoncmg.com/a
ssets/secs-geologySmartFiguresThe_Water_Cycle
Observe all the places where water is present on Earth
Atmosphere
Oceans
Glaciers
Rivers
Lakes: fresh
or salty
Biological
water
Swamps
and wetlands
Water in
minerals: may
be large
amount
Groundwater
17.01.a1
How Does Water Move? Water Cycle
Reservoirs
Sun provides
energy
Condensation
Air currents
Infiltration:
water
seeps
into
ground
Runoff
Evaporation
(oceans, lakes,
rivers,…)
Most precipitation
into ocean; some
evaporates on
way down
Precipitation
(rain, snow,
hail)
Groundwater
flows
Transpiration
from plants
Water Use in U.S.
17.02.a
Domestic Water
Needs
UN estimates that people
need a minimum of 50 liters
(~13 gallons) of water a day
for drinking, washing,
cooking and sanitation
• Average American uses 100176 gallons of water each day!
The Economy of Water
Industry
“hidden” water costs
• 30,000 gallons of water to produce
one ton of steel
• 200 gallons to make one pound of
synthetic rubber
• 184,000 gallons for a ton of high
quality book paper
• 1 gallon to brew a pint of beer
The 630 foot high,
stainless-clad
Gateway Arch, St.
Louis, Missouri
The Economy of Water
Agriculture
• 4,000 gallons to raise one pound of beef
• 500 gallons to grow one pound of rice
• 1,000 gallons to produce a liter of cow’s milk
• 1,300 gallons to grow one pound of cotton
• 5,300 gallons to fill kg jar coffee
National Rural Water Associatio
Water Usage in the US
322,000 million
gallons per day!
(USGS, 2018)
Source: https://water.usgs.gov/watuse/wuto.html
https://water.usgs.gov/watuse/wutrends.html
Mostly Thermoelectric withdrawal decrease
Increase irrigation and mining
Source: https://water.usgs.gov/watuse/wutrends.html
Water Use in U.S.
17.02.a
Observe all the places where water is present on Earth
Atmosphere
Oceans
Glaciers
Rivers
Lakes: fresh
or salty
Biological
water
Swamps
and wetlands
Water in
minerals: may
be large
amount
Groundwater
17.01.a1
How Does Water Move? Water Cycle
Reservoirs
Sun provides
energy
Condensation
Air currents
Infiltration:
water
seeps
into
ground
Runoff
Evaporation
(oceans, lakes,
rivers,…)
Most precipitation
into ocean; some
evaporates on
way down
Precipitation
(rain, snow,
hail)
Groundwater
flows
Transpiration
from plants
Hydrosphere has about 326
million cubic miles of water!
Streams
& Flooding
Rivers and
Flooding
Chapter
8
(Chapter 9)
2011 Missouri River Flood @ IA-Source:
NOAA
How Does Water Move? Water Cycle
Sun provides
energy
Condensation
Air currents
Runoff
Evaporation
(oceans, lakes,
rivers,…)
Most precipitation
into ocean; some
evaporates on
way down
Precipitation
(rain, snow,
hail)
Infiltration:
water
seeps
into
ground
Groundwater
flows
Transpiration
from plants
Runoff starts as thin sheets
->rills->gullies->streams
Can become rivers
17.01.b1
Stream…River?
• Stream- any body of
flowing water confined
within a channel,
regardless of size.
– ‘river’ is often used to
describe large streams
Streams…..
• Flow downhill through
topographic lows
• Carry away water over
earth’s surface.
https://mediaplayer.pearsoncmg.com/assets/39gUDZlEPbFv0zHlu53XTMH_7_wHmVGS
Water flows downhill
through topographic lows
Stream- any body of flowing water
confined within a channel, regardless of
size.
1. Flowing water changes size from
small to larger
Streams are classified by their size and by how many
streams have joined into them  stream order
First order streamssmall and have no other
streams flowing into them
When two first order
streams meet together
they form a second order
stream
As streams go up in
order, they get
Why is important to study streams?
• Source of freshwater
• Shape the Earth’s surface and
subsurface
– Erosion and weathering
– Earth material’s resources (sediment,
minerals…)
– Earth’s history
• Is an ecosystem for many species…
• Agriculture
• Hazards…floods
http://blogs.agu.org/landslideblog/2014/03/23/oso-landslide-1/
How Does Water Move? Water Cycle
Reservoirs
Sun provides
energy
Condensation
Air currents
Infiltration:
water
seeps
into
ground
Runoff
Evaporation
(oceans, lakes,
rivers,…)
Most precipitation
into ocean; some
evaporates on
way down
Precipitation
(rain, snow,
hail)
Groundwater
flows
Transpiration
from plants
Streams and Their Features
• Drainage Basin (watershed)- the region
from which a stream draws water
Drainage divides
separate basins
https://ees.as.uky.edu/sites/default/files/ele
arning/module12swf.swf
http://www.phillyh2o.org/backpages/Maps/SchuylkillWatershed.jpg
Streams and Their Features
Drainage divide
• Drainage Basin (watershed)- the
region from which a stream draws
water
• Drainage divides separate basins
Carries 40% of the US water flow!!!
Outlet
US Drainage Divides
Why this lake is so salty?
(Great Salt Lake, UT)
Why the Great Lakes are not so salty?
16.01.d4
Why oceans are salty?
Drainage Patterns:
Types and why?
Based on Geology of Area: rock type(s), geometry, etc.
Jointed bedrock
Weak & resistant rock
Flooding
• A flash flood= @ upper part river basin
• Intense, short rainfall @ small area
• Downstream flood happens when a stream overflows
its banks during times of higher discharge.
When water input exceeds the streams capacity
to carry water away
Historical Schuykill River flood list:
https://www.weather.gov/media/marfc/Floo
dClimo/SEPA/Philadelphia.pdf
Figure 5.5
Upper reach
“just
Middle reach
around
the river
bend”
Lower reach
https://mediaplayer.pearsoncmg.com/assets/secs-geologySmartFigures-Head_to_Mouth
How a stream channel changes?
https://mediaplayer.pearsoncmg.com/asset
s/secs-geology-SmartFiguresHead_to_Mouth
The ENERGY of flowing water changes
depending on the slope of the land
A high energy
A ‘reach’ is a
upper reach
section of
stream
The steeper the
land that water
flows down, the
faster it will
flow.
The faster
water flows,
the more
energy it has to
carry things.
Upper Reach
• When a stream is
flowing fast and the
gradient is steep 
rapid downcutting
happens
– large, boulder-sized
rocks in the stream
bed
– often a series of
pools and flows.
Streams don’t flow
straight for long...
V
V-shaped valley
and mostly
straight stream
Alluvial Fans
Formed where narrow, high
gradient stream enters
broad valley  sudden drop
in gradient + water depth
How an alluvial fan will look
in topo maps?
Alluvial: stream-deposited sediment
Google Earth Image
of an alluvial (inside
red circle). Note
the triangular or fan
shape characteristic
of them
Same alluvial fan as above, but
on a topo map. Note the
triangular or fan shape
characteristic of them, as well
as the spread out of the
contour lines. Alluvial fans can
occur at the valleys, down high
elevations, as a result of the
sudden drop in elevation (aka,
steep gradients). Recall that
on topo maps, steep is denoted
by close contour lines
Figure 5.5
Upper reach
“just
Middle reach
around
the river
bend”
Lower reach
How a stream channel changes?
https://mediaplayer.pearsoncmg.com/asset
s/secs-geology-SmartFiguresHead_to_Mouth
Figure 5.5
Upper reach
“just
Middle reach
around
the river
bend”
Lower reach
Alluvial Channel Patterns
Braided
Meander
Development of Meanders
Irregularities in the channel cause
changes in velocity
• Erosion occurs on
the side of the
channel where water
flows strongly (
cut bank)
• Deposition occurs
where it slows down
a bit (point bar)
Animation
“Anatomy” of Meandering Rivers
Inside
bend
Inside of bend= low velocity
Outside bend= faster velocity
Cutbank= erosion
Point Bar= deposition
Kahoot
Outside
bend
Pools= erosion
Deeply eroded channel
Rifle= shallow waters, sediment
deposition
Oxbow lakes/Cutoff Meanders
– Meanders
migrating toward
each other or…
– During floods
Kahoot
Animation
Floodplain
Middle Reach to
Lower Reaches
• Overtime downstream
meander migration
and sediment
deposition  a broad,
flat expanse of land
covered with sediment
(floodplain)
– Where the streams
spills over during
floods
Oxbows (cutoff
meanders)
Meandering Streams Features
https://mediaplayer.pearsoncmg.com/asset
s/secsgeol_proj_condor_meandering_rivers
Floodplain
Floodplain
https://mediaplayer.pearsoncmg.com/assets/xWGgTPn
sjzmTrRLkl9Z5_XWDzx8RbIsF
https://mediaplayer.pearsoncmg.com/asset
s/secs-geol-proj-condor-river-terracesbase-level
Mississippi River for features typical of low-gradient
rivers
Oxbow lake
Meander scars
Point bar
Cutbank
Meander
Cutoff
meander
16.08.b2
Google Earth image of the
Mississippi
River floodplain between
Illinois and Missouri
(barren brown area, left side
of image).
Topographic map
section
of the Mississippi
River floodplain (same
Shown above). Note
How the floodplain
looks on a topo map:
Flat or plain so the
contour lines are
spread out. Other
streams might have
floodplains on both
sides of the river, but
this one only has it on
its left or west side at
this location. Recall
that floodplains are
made (see other example at
http://home.moravian.edu/users/phys/mejjg01/geol
ogy/geology%20pages/geo_map_folder/geo_map_
pages/Floodplain.htm)
Flowing water energy changes
depending on the slope of the land
In the lower river reach, the energy is
very low, the river moves slowly and the
river bottom is small gravel and mostly
silt.
Lower reaches often
break into many different
channels
Distributary
How a stream channel changes?
https://mediaplayer.pearsoncmg.com/asset
s/secs-geology-SmartFiguresHead_to_Mouth
• Base level and deltas
Base level- the lowest elevation to
which the stream can erode
downward.
Base
Level
Delta @ Nile River
Deltas @ base level
Delta @ Mississippi River
Kahoot
Selenga River Delta@
Mongolia and Buryatia, Russia
Lake Baikal
Lake Baikal
Effects on a stream due to dam construction
Water slowdown
Increase sedimentation
Overall shape of the stream changes
Decrease sedimentation
Sediment capacity could increase
Slope could decrease
Bio & chem changes will occur too:
https://www.internationalrivers.org/environmental-impacts-of-dams
Stream Capacity
• Stream Capacity is a measure of the total
load of material a stream can move.
The faster water flows
 and the more water
present  the more
material can be
moved.
How a stream channel changes?
https://mediaplayer.pearsoncmg.com/asset
s/secs-geology-SmartFiguresHead_to_Mouth
Sediment Transport
Debris may:
• be rolled, dragged or pushed along
the bottom (traction load)- heavier
debris
• be carried in short hops along the
bottom (saltation)- intermediate size
Bed Load
• be suspended in the water- light or
fine debris
Suspended
Load
• be completely dissolved in the water
Dissolved
Load
How is Material Transported and Deposited?
Fine particles can be carried in
suspension (floating) in water
Sand grains can
roll and bounce
along
Cobbles and boulders
mostly roll and slide
during high flows
Soluble ions are dissolved in and
carried by moving water
Material moving on river
bed is bed load
16.02.a1
Observing Load in a Stream
• http://www.youtube.com/watch?v=7Z0Xw
YkqXy4
traction load
Saltation- particles move in short jumps
Streams & grain-size distrubution
As a stream slows down, it starts leaving
behind the heaviest, largest particles
 Stream deposited sediments are usually
well sorted by size and density
Big
small
smaller
Figure 5.5
Upper reach
“just
Middle reach
around
the river
bend”
Lower reach
Velocity, Gradient, and Base
Level
• Stream velocity is related partly to
discharge and to the steepness of slope.
– Gradient- the steepness of the stream
channel
• The higher the gradient, the steeper
the
Gradient Google Earth
channel
Stream Discharge
https://ees.as.uky.edu/sites/default/files/elearning/module12swf.swf
• Discharge
(Q)- the
volume of
water flowing
past a given
point in a
specified
length of time
• •Gauging
varies widely
stations
depending
on stream
size
• Can vary
with season,
weather…
Q=volume water*velocity
Volume water= depth*width
How data is collected?
http://geology.com/articles/gaging-station.shtml
Historic flood in PA: http://abcnews.go.com/2020/story?id=2918360&page=1
Schuylkill River data: https://waterdata.usgs.gov/usa/nwis/uv?01474500
Stream Hydrographs
• Plot of
fluctuations in
stream stage or
discharge
• Show trends in
stream behavior
over time
Yellowstone River Discharge
16.14.b1
How a stream channel changes?
https://mediaplayer.pearsoncmg.com/asset
s/secs-geology-SmartFiguresHead_to_Mouth
Flood Characteristics
• Stage: elevation of a stream surface
at a given point along the stream’s length
• Flood stage: when a stream exceeds
bank height
• Crest: maximum stage reached during a
flood event
bank
bank
Missouri River @ NE 2019 Flood
https://www.nytimes.com/interactive/2019/09/11/us/midwestflooding.html?fbclid=IwAR2_XuFAvBV5CYb7gKVJrbXClvosZotc62l6J3GNkCy-HlIJxXZD9HzpSn0
Flooding
• A flash flood= @ upper part river basin
• Intense, short rainfall @ small area
• Downstream flood happens when a stream overflows
its banks during times of higher discharge.
When water input exceeds the streams capacity
to carry water away
Harvey @ TX 2017: https://www.washingtonpost.com/graphics/2017/national/harvey-photosbefore-after/?utm_term=.b3f455659f5b
https://www.nytimes.com/interactive/2018/02/06/climate/flood-toxic-chemicals.html
Flood Characteristics
• Stage: elevation of a stream surface
at a given point along the stream’s length
• Flood stage: when a stream exceeds
bank height
• Crest: maximum stage reached during a
flood event
bank
bank
https://water.weather.gov/ahps/
Stream Hydrographs
• Plot of
fluctuations in
stream stage
or discharge
• Show trends
in stream
behavior over
time
Yellowstone River Discharge
16.14.b1
Source: NOAA
https://water.weather.gov/ahps2/hydrograph.php?wfo=phi&gage=ptnp1&hydro_type=2
Flooding
Most floods are linked to precipitation:
• Some sinks into the
ground (infiltration)
• Some water percolates
through soil and rock
• Some water on the
surface evaporates
All the rest of the water
becomes surface runoff
Flood Severity
Many factors together determine whether a flood
will occur.
• Important Factors:
Amount of
– Quantity of water
– Rate at which water enters the stream surface runoff
–
–
–
–
Porosity and permeability of sediments
Topography
Vegetation
Urbanization!!
Ex. In Southeast Asia storms can
produce 80 inches of rain in <3
days!!! (that’s more than double
annual rainfall in the US)
Runoff=
Stormwater!!!
How are streams affected on the last two scenario
What is lag time?
Stream Discharge: Hydrograph
Lag time
See also:
https://geographyas.info/rivers/dischargeand-hydrographs/
https://www.pennlive.com/life/2017/06/tropi
cal_storm_agnes_197_a_fiv.html
What
about
storm
sewers?
Interpret this graph
(times before
Urbanization)
100/500/1000 year floods?
• https://www.livescience.com/39633-100year-flood-colorado.html
• Video explanation:
https://scied.ucar.edu/whats-100-yearflood
Flood-Frequency Curves
See: https://www.grida.no/resources/6062
Recurrence Interval = (n+1)/Rank
• Constructed from
long-term records
• Function of
discharge and
recurrence
intervals (average
of how frequently
a flood of a certain
severity occurs)
P =100 ÷ RI
What is a 100-year flood?
• A flood with 1% probability in any given
year
P =100 ÷ the RI.
Recurrence intervals and probabilities of occurrences
Recurrence
interval, in years
Probability of
occurrence in any
given year
Percent chance of
occurrence in any
given year
100
1 in 100
1
50
1 in 50
2
25
1 in 25
4
10
1 in 10
10
5
1 in 5
20
2
1 in 2
50
FLOOD FREQUENCY PLOT
Plot RI vs. Peak Annual Discharge
Flood Frequency
Grand River @ Fulton St., Grand Rapids
Discharge (cfs)
100000
10000
1000
1
10
100
1000
Recurrence Interval (yrs)
Flood frequency activity
“100-year” flood
Recurrence interval & 100-year floods
Flood Recurrence Intervals For The Grand River Near Grand Rapids, MI
60 000
March 28, 1904
1% probability
Maximum Yearly Discharge (ft3/s)
50 000
40 000
April 21, 2013
4% probability
30 000
20 000
10 000
0
1
10
100
Recurrence Interval (Years)
1 000
Permeable
concrete
https://sourceable.net/pervious-concreteoffers-host-benefits/
Green Roofs
http://www.museumofthecity.org/green-roofs-in-cities/
Biowales
Other suggestions:
http://water.epa.gov/infrastructure/greeninfrastructure/gi_what.cfm
Flood Control
People vs. Nature
•
•
•
•
Channelization
Levees
Dams
reservoirs
What are some pros and
cons of common flood
control methods?
Use of Retention Ponds to
Moderate Flood Hazard
Artificial levees
http://www.floodsmart.gov/floodsmart/page
s/flooding_flood_risks/levee_simulator.jsp
Flood-control dams
Oklahoma: Cloud Creek Dam
Channelization
-Clearing
channel obstructions or changing the
river channel
-Straightening, deepening, widening, clearing…
-Can have other effects: increase erosion
What to do?
Lab: streams