U6115: Water
Monday, July 19 2004
The early bird may get
the worm…
but the second mouse
gets the cheese.
One thing we should remember from this summer
(and the last 6…)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
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Q ui ck Ti m e ™ an d a
T IF F ( Un co m p re ss ed ) d ec om pr e ss or
a re ne ed ed t o s ee th i s pi c tu r e.
Q ui ck Ti m e ™ an d a
T IF F ( Un co m p re ss ed ) d ec om pr e ss or
a re ne ed ed t o s ee h
t i s pi c tu r e.
Today: Water/Hydrology
• Intro to Hydrology
• Systems and Cycles
• Flux, Source/Sink, Residence time, Feedback
mechanisms…
U6115 Syllabus: Course Outline
• The water cycle part of the class is focused on basic
physical principles (evaporation, condensation,
precipitation, runoff, stream flow, percolation, and
groundwater flow), as well as environmentally relevant
applications based on case studies.
• Most specifically, students will be exposed to water
quantity and issues from global to regional scales and how
human and natural processes affect water availability in
surface and groundwater systems.
• Note: water quality issues will be mentioned but only
briefly since they have been covered more extensively in
the Environmental Chemistry course (ENVU6220)
U6115 Syllabus: Course Outline
Wk 8 - Jul 18-24
9:30AM-12:00PM
1-2PM
2-4PM
4-6PM
Wk 9 - Jul25-31
9:30AM-12:00PM
1-2PM
2-4PM
4-6PM
18-Jul
Final Exam
(1-3PM) Climate
25-Jul
NJ
19-Jul
Water 1
Pre-lab Meeting
Water 1 Lab-a
Water 1 Lab-b
20-Jul
Environ. Policy
Workshop
21-Jul
Toxico 2
Pre-lab Meeting
Toxico 2 Lab-a
Toxico 2 Lab-b
22-Jul
Pop 8
Pre-lab Meeting
Pop 8 Lab-a
Pop 8 Lab-b
26-Jul
Water 2
Pre-lab Meeting
Water 2 Lab-a
Water 2 Lab-b
27-Jul
Environ. Policy
Workshop
28-Jul
Toxico 3
Pre-lab Meeting
Toxico 3 Lab-a
Toxico 3 Lab-b
29-Jul
Pop 9
Pre-lab Meeting
Pop 9 Lab-a
Pop 9 Lab-b
Wk 10 - Aug 1-7
9:30AM-12:00PM
1-2PM
2-4PM
4-6PM
1-Aug
2-Aug
Water 3
Pre-lab Meeting
Water 3 Lab-a
Water 3 Lab-b
3-Aug
Environ. Policy
Workshop
4-Aug
Toxico 4
Pre-lab Meeting
Toxico 4 Lab-a
Toxico 4 Lab-b
5-Aug
Pop 10
Pre-lab Meeting
Pop 10 Lab-a
Pop 10 Lab-b
Wk 11 - Aug 8-14
9:30AM-12:00PM
1-2PM
2-4PM
4-6PM
8-Aug
9-Aug
Water 4
Pre-lab Meeting
Water 4 Lab-a
Water 4 Lab-b
10-Aug
Environ. Policy
Workshop
11-Aug
Toxico 5
Pre-lab Meeting
Toxico 5 Lab-a
Toxico 5 Lab-b
12-Aug
Pop 11
Pre-lab Meeting
Pop 11 Lab-a
Pop 11 Lab-b
Wk12 - Aug 15-19
9:30AM-12:00PM
1-2PM
2-4PM
4-6PM
15-Aug
16-Aug
Water 5
Pre-lab Meeting
Water 5 Lab-a
Water 5 Lab-b
17-Aug
Environ. Policy
Workshop
18-Aug
Water 6
19-Aug
Exam Pop/Land
1) Class 1: (July 19) Introduction - Water for the world - Lab 1: Global and regional water budgets
2) Class 2: (July 26) Global water issues - Hydrological cycle - Lab 2: Hydrological Forecasts and
their Communication to Decision-Makers
3) Class 3: (August 02) Dams & Reservoirs - Lab 3: Reservoirs and greenhouse gases
4) Class 4: (August 09) Condensation/Precipitation – Streamflow/Floods - Lab 4: Precipitation and
Flood predictions: A Statistical Analysis
5) Class 5: (August 16) Evaporation - Droughts – Land Use Impact on Streamflow
6) Class 6: (August 18) Groundwater flow - Groundwater transport
U6115 Syllabus: Grading (activities)
Water (40% of grade)
 Labs: 100% (4 formal labs)
 Mostly minds-on experiments with
computers. Lab report due
Water for the World
The role of water is central to most natural processes
• transport
– Weathering, contaminant transport
• energy balance
– transport of heat, high heat capacity
• greenhouse gas
– ~ 80% of the atmospheric greenhouse effect is caused by
water vapor
• life
– for most terrestrial life forms, water determines where they
may live; man is exception
Hydrology
• literally "water science," encompasses the study of
the occurrence and movement of water on and
beneath the surface of the Earth
• finite though renewable resource
– finite in quantity, unlimited in supply, use rate is
limited by 'recycling times'
• hydrologic sciences have pure and applied aspects
– how the Earth works
– scientific basis for proper management of water
resources (or any natural resource…)
Introduction to hydrology
use of water in 20th century has grown dramatically
Inventory of water on Earth
Water on land
3%
Lakes, soil moisture,
atmosphere, rivers
Deep groundwater
1%
(750-4000 m)
Shallow groundwater
(<750 m)
14%
11%
74%
97%
Ice caps and glaciers
Oceans
After Berner and Berner, 1987
Cycle Approach
 Some Definitions
 Transport and transformation processes within definite reservoirs: Carbon,
Rock, Water Cycles
 Reservoir: (box, compartment: M in mass units or moles) An amount of
material defined by certain physical, chemical, or biological characteristics
that can be considered homogeneous
– O2 in the atmosphere
– Carbon in living organic matter in the Ocean
– Water in the Ocean
 Flux: (F) The amount of material transferred from one reservoir to another
per unit time (M/s or M/s.L2)
– The rate of evaporation of water from the surface Ocean
– The rate of deposition of inorganic carbon (carbonates on marine
sediments
 Source: (I or Q) A flux of material into a reservoir
 Sink: (O or S) A flux of material out of a reservoir
More Definitions…
 Budget: A balance sheet of all sources and sinks of a reservoir.
If sources and sinks balance each other and do not change with
time, the reservoir is in steady-state (M does not change with
time). If steady-state prevails, then a flux that is unknown can
be estimated by its difference from the other fluxes.
for a control volume this means: dM/dt = I'-O'
 Turnover time: The ratio of the content (M) of the reservoir to
the sum of its sinks (O) or sources (I). The time it will take to
empty the reservoir if there aren’t any sources. It is also a
measure of the average time an atom/molecule spends in the
reservoir. Or:
0 = M/O (or M/I)
 Cycle: A system consisting of two or more connected
reservoir, where a large part of the material (energy) is
transferred through the system in a cyclic fashion
The Water (Hydrologic) Cycle
The Water Cycle (in detail)
 The volume (M) of water at the surface of the Earth is
enormous: 1.37 109 km3! (total reservoir) – The Oceans cover
71% of the Earth’s surface (29% for the continent masses
above sea level)
Reservoir
Biosphere
Volume (km3)
0.6 103
Rivers
Atmosphere
Lakes
Groundwater
Glacial and other land ice (?)
Oceanic water and sea ice
Total
% Total
0.00004
1.7 103
13 103
125 103
9500 103
29000 103
0.0001
0.001
0.01
0.68
2.05
1,370,000 103
97.25
1,408,640 103
Adapted from Berner & Berner (The Global Water Cycle; Prentice Hall, 1987)
100
Fluxes (F in 103 km3/yr)
 Of total yearly evaporation, 84% evaporates from the Oceans and 16%
from surface of continents.
 However, return to Earth via precipitation: 75% falls directly on the
Oceans and 25% on the continents.
 During the year, the atmosphere transports 9% of Oceans’ evaporation
to the continents!
 This water is returned via surface streams and as groundwater
Errors!
 Precipitation and
evaporation are difficult to
measure precisely over the
oceans. They are mostly
estimated from models and
satellite data.
 Groundwater reservoir
estimates bear a inherent
error in the fact that they
are indirectly determined.
 Soil moisture and
evapotranspiration rates
depend on indirect
measurements and average
soil quality and
global/regional respiration
rates
Residence Time
(years – months – weeks)
 High probability that a certain fraction of the atoms or molecules forming
the reservoir (M) will be of a certain age (mean age of the element when it
leaves the reservoir)
 The simplified residence time  turnover time
The time it would take to empty a reservoir if the sink (O or “outflow”)
remained constant while the sources were zero
0 = M/O (or M/I)
M = 0O
Residence time of water in the atmosphere
M = ?; O = ?; 0 = ?
M = 13 103 km3
S = 297(O) + 99(C) 103 km3/yr = 396 103 km3/yr
0 = 0.033 yr = 12 days!
Replacement ~30 times/year
Residence Time
(years – months – weeks)
 High probability that a certain fraction of the atoms or molecules forming
the reservoir (M) will be of a certain age (mean age of the element when it
leaves the reservoir)
 The simplified residence time  turnover time
The time it would take to empty a reservoir if the sink (O) remained constant
while the sources were zero

0
= M/O (or M/I)
M = 0O
Residence time of water in the ocean
M = ?; S = ?; 0 = ?
M = 1,370,000 103 km3
S = 334 103 km3/yr (evaporation)
0 = M/S = 4102 yrs!
Continental Mass Balance
• quantitative description  applying the principle of conservation of mass
• for continents as control volume this can be written as
dV/dt = p - rso - et = 0 (all averaged)
• on average this means: p = rso+ et
• the water budget for all land areas of the world is: p=800mm, rs = 310mm, and et
= 490mm
• the global runoff ration (rs/p) is ~39% there are lots of local and regional
variations.
System Approach…
Feedback: All closed and open systems respond to inputs
and have outputs. A feedback is a specific output that
serves as an input to the system.
Negative Feedback (stabilizing): The system’s response is
in the opposite direction as that of the output. CLOUDS!
System Approach…
Positive Feedback (destabilizing): The system’s
response is in the same direction as that of the output.
Number of bacteria
"Bacteria in a bottle"
1.4E+18
1.2E+18
1.0E+18
8.0E+17
6.0E+17
4.0E+17
Bottle half full
2.0E+17
0.0E+00
0
10
20
30
40
Time (minutes)
50
59 min
60
System Approach…
Positive Feedback (destabilizing):
CLOUDS!
Surface waters
BRF
Watershed, catchment, drainage basin
Catchement (drainage basin, watershed): the basic unit of
volume (control) which is an area of land in which water flowing
across the land surface drains into a particular stream and
ultimately flows a single point or outlet.
dV/dt = p - rso - et = 0
on average  p = rso + et
Catchment
Our concern with precipitation and evapotranspiration is in
knowing the rates, timing, and spatial distribution of these
water fluxes between the land and the atmosphere.
dV/dt = p - rso - et = 0
Texas
New York
Measurement techniques
 precipitation
 evapotranspiration
Evapotranspiration
Average statewide evapotranspiration for the conterminous United States
range from about 40% of the average annual precipitation in the Northwest
and Northeast to about 100% in the Southwest.
Annual Precipitation - Australia
Annual Evaporation - Australia
Annual Evapotranspiration - Australia
Rivers and
Streams
Measurement techniques
 flow depth (stage)
 discharge
Colorado River
hydrograph
Questions:
• When does discharge peak and
why?
• The hydrographs were taken at
different locations of the river,
what is the difference in the
hydrographs and why is there
one?
Colorado River
hydrograph
• Hydrographs are
variable between years
• Discharge often peaks
in late winter or
spring, snowmelt
• Reservoirs smooth out
extremes
Canada del Oro hydrograph
 extended periods with no discharge at all!
http://water.usgs.gov
Santa Cruz River (Tucson, AZ, 1930 vs. 1964 - 1983 flood)
Lakes and
Reservoirs
Reservoir distribution in the U.S.
Wetlands
Definition (U.S. Fish and Wildlife Service):
"WETLANDS are transitional systems between terrestrial and aquatic systems
where the water table is usually at or near the surface or the land is covered by
shallow water. For purposes of this classification wetlands must have one or
more of the following three attributes:
(1) at least periodically, the land supports predominantly hydrophytes;
(2) the substrate is predominantly undrained hydric soil; and
(3) the substrate is saturated with water or covered by shallow water at some time
during the growing season of the year."
Hydrologic conditions: Groundwater (water table or zone of saturation) is
at the surface or within the soil root zone during all or part of the
growing season.
Hydric soils: soils that are saturated, flooded, or ponded long enough during
the growing season to develop oxygen-free conditions in the upper six
inches
Hydrophytic vegetation: plants typically adapted to wetland and aquatic
habitats; plants which grow in water or on a substrate that is at least
periodically deficient in oxygen due to excessive water content.
Wetlands are classified into two general categories: coastal and
inland. Coastal wetlands are further classified into marine and
estuarine categories
Inland wetlands are further subdivided in riverine, lacustrine, and
palustrine wetlands.
Bog
Fen
Mire
Marsh
Playa
Slough
Peat accumulation usually dominated by moss. Receives
only direct precipitation; characterized by acid water, low
alkalinity, and low nutrients.
Peat accumulation; ma y be dominated by sedge, reed,
shrub or forest. Receives some surface runoff and/or
ground water, which has neutral pH and moderate to high
nutrients.
Used mainly in Europe to include any peat-forming wetland
(bog or fen).
Permanently or periodically inundated site characterized by
nutrient-rich water. In Europe, must have a mineral
substrate and lack peat accumulation.
Shallow, ephemeral ponds or lagoons that experience
significant seasonal changes in semi-arid to arid climates.
Often have high salinity or may be completely dry.
Widely used term for wetland environment in a channel or
series of shallow lakes. Water is stagnant or may flow
slowly on a seasonal basis. Synonym--bayou.
Characterized by forest, shrub, or reed cover (fen).
Swamp Particularly a forested wetland in North America. Depends
on nutrient-rich ground water derived from mineral soils.
Wet
Open prairie, grassland or savannah with waterlogged soils
meadow but without standing water for most of the year.
Open
water
Deeper, normally perennial pools within wetlands and
shallow portions of lakes and rivers. Typically home to
submerged macrophytes.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Fens receive water from the surrounding watershed in inflowing streams and
groundwater, while bogs receive water primarily from precipitation. Fens, therefore,
reflect the chemistry of the geological formations through which these waters flow.
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Loss of floodplain forested wetlands and
confinement by levees have reduced the
floodwater storage capacity of the Mississippi
by 80 percent increasing dramatically the
potential for flood damage.
The 1993 flood proved this prediction to be
true and resulted in immeasurable damage
Benefits of
Wetlands
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Coastal Wetlands
Tidal coastal wetlands store carbon densely, holding on to 10% of the
global stock of soil organic carbon in only 0.1% of the Earth’s surface.
Despite their relatively small area (203 103 km2), tidal coastal wetlands
may act as substantial sinks for atmospheric carbon due both to
exceptional carbon burial fluxes and negligible CH4 and N2O
emissions.
Because the projected sequestration efforts in North American
croplands (0.5-2.5 Pg C) are of the same order of magnitude as C
stocks estimated to exist in the surface meter of wetlands (~4 Pg),
major losses of these ecosystems could easily offset any improvement
in preservation of SOC within managed croplands even at its highest
efficiency.
In many coastal regions (i.e. Louisiana Gulf Coast), these wetlands are
being lost are substantial rates (50-100 km2/yr)
Groundwater
Groundwater flow is
controlled by
– differences in water table
(hydraulic head)
– hydraulic conductivity
(relation between specific
discharge – Vol/t – and
hydraulic gradient)
– Hydraulic conductivity
depends on both the nature
of the fluid (viscosity) and
the porosity of the material
Hornberger et al., 1998
Measurement techniques
 Hydraulic head, conductivity