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CWA Hydrologic cycle Global weather patterns

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Title: CWA Hydrologic cycle Global weather patterns


1
CWA Hydrologic cycle Global weather patterns
  • Global Water Issues
  • 9 January 2007

2
CWA
  • Federal Water Pollution Control Act (1972)
  • Considered the cornerstone of surface water
    quality protection in the US
  • Authorized EPA to implement pollution control
  • Regulatory and non-regulatory tools to reduce
    pollutant discharge into waterways
  • Finance municipal wastewater treatment facilities
  • Manage polluted runoff
  • Required water quality criteria
  • Initial focus
  • Chemical integrity
  • Regulate point source discharges
  • States must follow or justify changes
  • Clean Water Amendment of 1977, 1981, 1987, 1990

3
CWA
  • Provides tools to achieve the broader goal of
    restoring and maintaining the chemical, physical,
    and biological integrity of the nation's waters
    so that they can support "the protection and
    propagation of fish, shellfish, and wildlife and
    recreation in and on the water."

4
The Big Picture
http//www.epa.gov/region5/water/cwa.htm
5
The Big Picture
  • 303(d) States list of impaired waters
  • NPDES National pollutant discharge elimination
    system (point source)
  • 401 NPDES 404 State water quality
    certification
  • 404 USACE dredged or fill material into
    water of US
  • 319 State NPS management (5yrs)
  • SRF replaced funding for municipal sewer
    treatment Provides grants for water
    quality projects

http//www.epa.gov/region5/water/cwa.htm
6
303d list of impaired waterways
7
WQC
  • Ambient water quality criteria defines
  • Pollutant
  • Speciation
  • Variance factors
  • Based on species specific endpoints
  • Peer-reviewed published manuscripts
  • Ranks species according to sensitivity
  • Incorporates variance factors (temp/pH)

8
Water quality standards
  • Set by the states
  • Most states have environmental governing
    departments
  • Other states governed by the US EPA
  • Standards vs. criteria
  • States ? standards
  • Site specific
  • Species present
  • Numerical vs. descriptive

9
Water quality standards
  • Advantages of state DEQs
  • Define site-specific requirements
  • Species survey
  • Background levels
  • HUC units
  • Species of concern
  • listed / threatened / endangered
  • 303D listing / delisting

10
Water quality standards
  • Concerns for state DEQs
  • Cost
  • Variations on theme
  • Sites, background values, 8-12 digit HUC units
  • Flow regime
  • Surveys
  • Historical data vs. new surveys
  • Restoration

11
How to eat an elephant
  • One bite at a time……
  • Ecoregion approach
  • Watershed approach
  • Approach used most recently for CWA compliance
  • HUC
  • 8 12 unit approach
  • Stream segments
  • Site specific

12
Water quality standards
  • Analytical/chemical values
  • Based on acute toxicity testing endpoints
  • GMAV
  • FMAV (geometric mean of GMAVs)
  • Endpoints not available for all species
  • Sensitive species vs. surrogate species

13
Not take into account…
  • Changes in flow regime
  • Seasonal
  • Low flow seasons change in water quality
    parameters
  • Trends in groundwater / surface water
  • Influent vs. effluent systems
  • Additional stressors
  • Additive / synergistic effects
  • Limited variables taken into account
  • Biotic / abiotic effects

14
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15
Watershed the fundamental hydrologic unit of
land that contributes surface water to a stream.
Drainage divide a ridge of high ground along
which all rainfall is shed as runoff down one
side of the rise or the other
16
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17
The hydrological cycle
Fetter, 2001
18
Freshwater resources
  • Of the available freshwater (lt1 earths water)
  • Subsurface water 99 of freshwater resources

Fetter, 2001
Younger, 2006
19
Subsurface water
  • Groundwater soil moisture
  • Water table
  • The horizon of available groundwater
  • Soil moisture above the water table
  • Groundwater below the water table
  • Aquifer body of saturated rock that stores and
    transmits important quantities of groundwater
  • Aquitard saturated body of rock that impedes
    movement of groundwater
  • Confined lying below an aquitard
  • Unconfined upper limit of saturation (except
    the capillary fringe) is the water table

20
Subsurface water distribution
Typical distribution of subsurface waters in an
unconfined aquifer setting.
Younger, 2006
21
Subsurface water flow
  • Subsurface water flow
  • Vertical percolation horizontal subsurface
    movement
  • Interflow lateral flow in the vadose zone

Fetter, 2001
22
Influent (losing) river loses water by
infiltration into the ground Effluent (gaining)
river gains water through inflow of
groundwater. Depth of the water table may
fluctuate in response to recharge and discharge.
23
Water cycle
  • A. Water as a medium for material movement
  • B. Solar energy drives evaporation driving
    force
  • C. Precipitation/ interception
  • D. Infiltration/ groundwater
  • E. Up the plants ? transpiration
  • F. Ground plants evapotranspiration
  • G. Water movements shape freshwater marine
    environment
  • H. Tides from sun moon

24
Smith Smith 2006
25
Water cycle
Smith Smith 2006
  • Precipitation ? infiltration ? groundwater
  • Precipitation ? infiltration ? transpiration
  • Precipitation ? infiltration ? subsurface flow
  • Precipitation ? surface runoff ? surface water ?
    evaporation
  • Precipitation ? interception ? evaporation

26
Angular arrangement and open structure
Smith Smith 2006
27
Waters Unique Characteristics
  • A. Structure
  • Hydrogen bonds between H2O molecules
  • - cohesion (sticking together)
  • 2. Covalence- shared electrons between H O
  • 3. 105o ? polarity
  • Ice completing the lattice (gt density 3.98o
    C)
  • 5. Seawater solution of salts NaCl
  • 34.5 g salt / 1000 g water

Smith Smith 2006
28
Water characteristics, contd
  • B. Specific heat - calories to raise 1 gm water
    1 C, storage of heat and resist change
  • C. Evaporation liquid to gas
  • D. Viscosity - resistance of a liquid to flow
  • - again, H-bonds
  • E. Surface tension breaking the barrier
  • Buoyancy wt. of object lt displaced water

Smith Smith 2006
29
Water as a solvent
  • Solution / solvent
  • Dissolution of ions (cations/anions)
  • Rainwater / groundwater / surface water
  • Movement of minerals and salts
  • CO2 solubility
  • Carbonate alkalinity equilibrium
  • CO2 H2O ?? H2CO3
  • H2CO3 ?? HCO3- H
  • HCO3- ?? H CO32-

30
Global weather patterns
  • Inherent climate change
  • Earths axis (22.5 24)
  • Influences climate
  • 41,000 yr cycle
  • Ice ages
  • 10,000 - 15,000 yrs ago
  • North American Ice Age

31
Atmospheric CO2
  • Increased by gt 25 / past 100 years
  • 1850 280ppm
  • 1995 360 ppm
  • Greenhouse effect / greenhouse gases
  • Glacial air bubbles provides history
  • Deforestation
  • Land clearing / atmospheric CO2 complex issue
  • Carbon sequestration

Smith Smith 2006
32
CO2 fate
  • Sinks
  • Oceanuptake from atmosphere
  • Terrestrial ecosystemsreforestation
  • Key component of carbon sequestration
  • Uptake by photosynthesis exceeds losses by
    respiration

Smith Smith 2006
33
Ocean as a sink
  • CO2 diffuses from atmosphere into surface waters
  • Transformed into carbonates and bicarbonates
  • Never reaches equilibrium
  • Atmospheric CO2 rises rise in oceanic
    sequestration

34
Limits of ocean sequestration
  • Ocean waters not homogeneous
  • CO2 absorption limited to epilimnion
  • Does not mix below thermocline
  • Deep water currents take 100s years to mix

35
Terrestrial ecosystems
  • Plants increase photosynthesis rate with
    increased CO2
  • CO2 fertilization effect
  • Limiting factors in photosynthesis
  • Controls carbon sequestration

Smith Smith 2006
36
Greenhouse effect
  • CO2 absorbs long-wave radiation from earth
  • Acts as thermal blanket
  • Greenhouse gases
  • CO2 most plentiful
  • By 2050, 2oC rise in temperature
  • Not evenly distributed
  • Global warming or global climate change

37
Climate change
  • Climate change ecosystem change
  • Distribution and abundance of species changes
  • Indirect and direct effects
  • Change in evaporation/transpiration
  • Forest migrations
  • Aquatic ecosystem distribution affected
  • Coral reefs

38
Rise in sea level
  • Warming will cause rise in sea level
  • Change coastal environments
  • Estuary ecosystems
  • sensitive areas
  • nurseries
  • Ocean rise 1.8 mm/year
  • Oceanic cities
  • Coastal wetlands
  • Barrier islands

Smith Smith 2006
Portage glacier 1988-1998
39
Agricultural effects
  • Range in temperature and precipitation for crops
  • Developing countries

Smith Smith 2006
40
Tropical zones that could support tropical rain
forests a) under present climate conditions b)
under conditions predicted by the UK
Meteorological Office for doubled atmospheric CO2
concentrations
  • Put global figure here

Smith Smith 2006
41
Sum it up
  • Protecting our resources
  • Includes protecting quantity and quality
  • Protection of groundwater resources
  • Groundwater 99 of freshwater resources
  • Part of the water cycle
  • Groundwater quality and quantity
  • Climate change
  • Change in the hydrological cycle
  • Evaporation and transpiration
  • Precipitation quantity
  • Precipitation patterns

42
Things to ponder
  • US CWA does not address
  • water quantity
  • groundwater resources
  • out of sight out of mind???
  • Climatic changes effects on water cycles
  • Increased temp
  • Increased evaporation
  • Increased violent weather
  • Agricultural production changes
  • Changes in developing countries
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