CLEAN WATER ACT
Michael J. Kennish
Department of Marine and Coastal Sciences,
School of Environmental and Biological Sciences,
Rutgers University, New Brunswick, NJ, USA
Synonyms
Federal Water Pollution Control Act Amendments
Definition
The US Congress enacted the Clean Water Act in 1972
(P.L. 92-500, the 1972 Amendments to the Federal Water
Pollution Control Act), which is the principal law dealing
with polluting activity in streams, rivers, lakes, and estuaries of the USA (Copeland, 2006). The Clean Water Act
established a water quality standards approach for regulating water quality, with the US Environmental Protection
Agency responsible for developing national water quality
criteria. A waterbody found to be in violation of a water
quality standard was to be listed as “impaired” with consideration of the establishment of a total maximum daily
load (TMDL) of the pollutant in violation of the standard
(Lee et al., 2005).
Description
The Federal Water Pollution Control Act was originally
enacted in 1948 and later amended in 1972 as the Clean
Water Act (P.L. 92-500). Subsequent amendments were
made in 1977 (P.L. 95-217), 1981 (P.L. 97-117), and
1987 (P.L. 100-4). As noted by Copeland (2006), the
Clean Water Act consists of two main parts: “regulatory
provisions that impose progressively more stringent
requirements on industries and cities in order to meet the
statutory goal of zero discharge of pollutants, and
provisions that authorize federal financial assistance for
municipal wastewater treatment construction.”
Bibliography
Copeland, C., 2006. Water Quality: Implementing the Clean Water
Act. Washington, DC: Congressional Research Service. CRS
Report for Congress, Order Code RL33466.
Lee, G. F., and Jones-Lee, A., 2005. Clean Water Act, water quality
criteria/standards, TMDLs, and weight-of-evidence approach for
regulating water quality. In Water Encyclopedia: Water Law and
Economics. Hoboken, NJ: Wiley, pp. 598–604.
Cross-references
Anoxia, Hypoxia, and Dead Zones
Eutrophication
Halogenated Hydrocarbons
Nonpoint Source Pollution
Oil Pollution
Polycyclic Aromatic Hydrocarbons
Trace Metals in Estuaries
Water Quality
CLIMATE CHANGE
Thomas M. Cronin
US Geological Survey, Reston, VA, USA
Synonyms
Climate variability
Definitions
Climate change (including climate variability) refers to
regional or global changes in mean climate state or in patterns of climate variability over decades to millions of
years often identified using statistical methods and sometimes referred to as changes in long-term weather conditions (IPCC, 2012). Climate is influenced by changes in
continent-ocean configurations due to plate tectonic processes, variations in Earth’s orbit, axial tilt and precession,
atmospheric greenhouse gas (GHG) concentrations, solar
variability, volcanism, internal variability resulting from
interactions between the atmosphere, oceans and ice
(glaciers, small ice caps, ice sheets, and sea ice), and
anthropogenic activities such as greenhouse gas emissions
and land use and their effects on carbon cycling.
Introduction
Earth’s climate has varied over all timescales due to
changes in global energy balance and radiative forcing
caused by changes in solar radiation reaching Earth’s
atmosphere, volcanism, Earth’s orbital configuration
(precession, tilt, eccentricity), atmospheric greenhouse
gas concentrations, and ocean basin-continent distributions. Regional and global climate changes can be amplified or dampened by complex feedback mechanisms
involving sea-ice albedo, methane release from permafrost and marine sediments, land surface vegetation cover,
ice sheet dynamics, and atmosphere-ocean-land exchange
of carbon dioxide. In addition to natural climate changes,
there is substantial evidence from instrumental records,
climate modeling, and paleoclimate reconstructions that
humans have influenced global and regional climate.
Estuaries, inlets, bays, fjords, tidal marshes, and other
coastal systems are directly or indirectly affected by climate change. Instrumental records from stream gauges,
water quality measurements, and, more recently, satellites
provide trends in salinity, temperature, turbidity, dissolved
oxygen, and many other parameters that can be linked to
regional climate change and variability. Climate, hydrological, and ecosystem modeling studies are another
approach to understanding climate impacts. For example,
there are growing efforts to project estuarine response to
elevated greenhouse gas concentrations (Najjar et al.,
2010) some using downscaling methods that link global
climate and regional models (Hostetler et al., 2011).
Because instrumental records are usually limited to the last
few decades, a third approach employs paleoclimatic and
122
CLEAN WATER ACT
Michael J. Kennish
Department of Marine and Coastal Sciences,
School of Environmental and Biological Sciences,
Rutgers University, New Brunswick, NJ, USA
Synonyms
Federal Water Pollution Control Act Amendments
Definition
The US Congress enacted the Clean Water Act in 1972
(P.L. 92-500, the 1972 Amendments to the Federal Water
Pollution Control Act), which is the principal law dealing
with polluting activity in streams, rivers, lakes, and estuaries of the USA (Copeland, 2006). The Clean Water Act
established a water quality standards approach for regulating water quality, with the US Environmental Protection
Agency responsible for developing national water quality
criteria. A waterbody found to be in violation of a water
quality standard was to be listed as “impaired” with consideration of the establishment of a total maximum daily
load (TMDL) of the pollutant in violation of the standard
(Lee et al., 2005).
Description
The Federal Water Pollution Control Act was originally
enacted in 1948 and later amended in 1972 as the Clean
Water Act (P.L. 92-500). Subsequent amendments were
made in 1977 (P.L. 95-217), 1981 (P.L. 97-117), and
1987 (P.L. 100-4). As noted by Copeland (2006), the
Clean Water Act consists of two main parts: “regulatory
provisions that impose progressively more stringent
requirements on industries and cities in order to meet the
statutory goal of zero discharge of pollutants, and
provisions that authorize federal financial assistance for
municipal wastewater treatment construction.”
Bibliography
Copeland, C., 2006. Water Quality: Implementing the Clean Water
Act. Washington, DC: Congressional Research Service. CRS
Report for Congress, Order Code RL33466.
Lee, G. F., and Jones-Lee, A., 2005. Clean Water Act, water quality
criteria/standards, TMDLs, and weight-of-evidence approach for
regulating water quality. In Water Encyclopedia: Water Law and
Economics. Hoboken, NJ: Wiley, pp. 598–604.
Cross-references
Anoxia, Hypoxia, and Dead Zones
Eutrophication
Halogenated Hydrocarbons
Nonpoint Source Pollution
Oil Pollution
Polycyclic Aromatic Hydrocarbons
Trace Metals in Estuaries
Water Quality
CLIMATE CHANGE
Thomas M. Cronin
US Geological Survey, Reston, VA, USA
Synonyms
Climate variability
Definitions
Climate change (including climate variability) refers to
regional or global changes in mean climate state or in patterns of climate variability over decades to millions of
years often identified using statistical methods and sometimes referred to as changes in long-term weather conditions (IPCC, 2012). Climate is influenced by changes in
continent-ocean configurations due to plate tectonic processes, variations in Earth’s orbit, axial tilt and precession,
atmospheric greenhouse gas (GHG) concentrations, solar
variability, volcanism, internal variability resulting from
interactions between the atmosphere, oceans and ice
(glaciers, small ice caps, ice sheets, and sea ice), and
anthropogenic activities such as greenhouse gas emissions
and land use and their effects on carbon cycling.
Introduction
Earth’s climate has varied over all timescales due to
changes in global energy balance and radiative forcing
caused by changes in solar radiation reaching Earth’s
atmosphere, volcanism, Earth’s orbital configuration
(precession, tilt, eccentricity), atmospheric greenhouse
gas concentrations, and ocean basin-continent distributions. Regional and global climate changes can be amplified or dampened by complex feedback mechanisms
involving sea-ice albedo, methane release from permafrost and marine sediments, land surface vegetation cover,
ice sheet dynamics, and atmosphere-ocean-land exchange
of carbon dioxide. In addition to natural climate changes,
there is substantial evidence from instrumental records,
climate modeling, and paleoclimate reconstructions that
humans have influenced global and regional climate.
Estuaries, inlets, bays, fjords, tidal marshes, and other
coastal systems are directly or indirectly affected by climate change. Instrumental records from stream gauges,
water quality measurements, and, more recently, satellites
provide trends in salinity, temperature, turbidity, dissolved
oxygen, and many other parameters that can be linked to
regional climate change and variability. Climate, hydrological, and ecosystem modeling studies are another
approach to understanding climate impacts. For example,
there are growing efforts to project estuarine response to
elevated greenhouse gas concentrations (Najjar et al.,
2010) some using downscaling methods that link global
climate and regional models (Hostetler et al., 2011).
Because instrumental records are usually limited to the last
few decades, a third approach employs paleoclimatic and
122
CLEAN WATER ACT