Glossary
Acre-Foot (AF)
The quantity of water that will cover an acre of land to a depth of
one foot (i.e., 43,560 cubic feet or 325,900 gallons).
Acute Effect
Any toxic effect that is produced within a short period of time, generally
96 hours or less. Although the effect most frequently considered is
mortality, the end result of an acute effect could be any harmful biological
effect.
Algae
Simple rootless plants that grow in bodies of water at rates in relative
proportion to the amounts of nutrients available in the water or, in
the case of nitrogen, in the atmosphere overlying the water body.
Ambient Monitoring
Monitoring that is done to determine existing environmental conditions,
pollutant levels, rates, or species in the environment.
Amphipods
Small shrimp-like crustaceans such as sand fleas and related forms.
Many live on the bottom (i.e., are benthic) and feed on algae and detritus.
Anadromous
Pertaining to fish that spend part of their life cycle in the ocean
and return to freshwater streams to spawn.
Beneficial Use
Uses of waters of the State that may be protected against quality degradation.
They include, but are not limited to, domestic municipal, agricultural,
and industrial supply; power generation; recreation; aesthetic enjoyment;
navigation; and preservation and enhancement of fish, wildlife, and
other aquatic resources or preserves. [Cal. Water Code Sec. 1 3050(f)].
Benthic Organisms
Organisms that live in or on the bottom of a body of water.
Benthos
The whole assemblage of plants or animals living on the bottom of a
water body; distinguished from plankton.
Bioaccumulation
The process by which a pollutant accumulates in the tissues of an organism.
For example, certain chemicals in food eaten by a fish tend to accumulate
in its liver and other tissues.
Bioassay
A test procedure that measures the response of living plants, animals,
or tissues to potential pollutants. For example, water fleas have been
exposed to the waters of the Bay/Delta estuary, and their responses
have been used to determine if the water is harmful to life.
Bioavailability
The extent to which a pollutant is available for uptake and accumulation
by living organisms.
Biochemical Oxygen Demand (BOD)
The quantity of oxygen-demanding materials present in a sample as measured
by a specific test. A major objective of conventional wastewater treatment
is to reduce the biochemical oxygen demand so that the oxygen content
of the water body will not be significantly reduced. Although BOD is
not a specific compound, it is defined as a conventional pollutant under
the federal Clean Water Act.
Biomagnification
The process by which concentrations of pollutants increase (magnify)
as they pass up the food web such that each animal in the food web has
higher tissue concentrations than did its food. For example, concentrations
of certain pollutants can increase as they are passed from plankton
to salmon to seals.
Biota
The animals, plants, and microbes that live in a particular location
or region.
Bivalve
An aquatic invertebrate animal of the class Bivalvia. Bivalves, such
as clams and oysters, have two shells (valves), and most are filter
feeders.
Bloom
A proliferation of algae and/or higher aquatic plants in a body of water.
Brackish Water
Water containing dissolved minerals in amounts that exceed normally
acceptable standards for municipal, domestic, and irrigation uses. Brackish
water is considerably less saline than sea water.
Carcinogenic
Causing cancer.
Chronic
Effect Any toxic effect on an organism that results after exposure of
long duration (often l/l0th of the life span or more). The end result
of a chronic effect can be death, although the usual effects are sublethal
(e.g., inhibited reproduction or growth). These sublethal effects may
be reflected by changes in the productivity and population structure
of the community.
Combined Sewer Overflow (CSO)
A pipe that discharges untreated wastewater during storms from a sewer
system that carries both sanitary wastewater and stormwater. The overflow
occurs because the system does not have the capacity to transport, store,
or treat the increased flow caused by stormwater runoff.
Conventional Pollutant
Conventional pollutants as specified under the federal Clean Water Act
are total suspended solids, fecal coliform bacteria, biochemical oxygen
demand, pH, and oil and grease. Today a large number of nonconventional
and toxic pollutants are of concern in addition to the conventional
pollutants.
Copepod
A type of herbivorous microscopic crustacean (subclass Copepoda). Copepods
are very important in the food chain because they are eaten by many
fish or by other organisms that are eventually eaten by fish.
Dichloro diphenyl trichloroethane (DDT)
A chlorinated hydrocarbon insecticide whose accumulation and persistence
in aquatic and terrestrial ecosystems led to its ban in the United States
in 1971 for virtually all but emergency uses. DDT metabolites include
DDE and DDD.
Delta
The delta of the Sacramento and San Joaquin rivers as defined in the
California Water Code, Section 12220.
Delta Inflow
Freshwater flows entering the Sacramento-San Joaquin Delta in the Sacramento,
Cosumnes, Mokelumne and San Joaquin rivers; the Yolo Bypass; and various
small streams draining the lands east of the Delta.
Delta Outflow
Freshwater flows from the Delta into San Francisco Bay. This flow is
calculated as total Delta inflow plus precipitation, minus in-Delta
uses and exports.
Deposit Feeder
Organisms that feed on organic material on and in bottom sediments.
Because they ingest sediments directly to extract the organic component,
these organisms may concentrate toxic contaminants.
Depuration
The holding of clams, mussels, or oysters (for commercial or bioassay
purposes) in clean water until pollutants are removed from the gut.
Detritus
Dead organic material comprising mostly phytoplankton, large aquatic
plants, and litter from terrestrial vegetation. This material provides
substantial amounts of organic carbon to the estuary and may be an important
source of energy for the food web in some parts of the estuarine ecosystem.
Disinfection Byproducts
Pollutants formed when organic materials in a drinking water source
react with the disinfectant, such as chlorine or ozone. Trihalomethanes
(THMs) are a major group of disinfection byproducts.
Dissolved Oxygen
Oxygen that is present (dissolved) in water and therefore available
for fish and other aquatic animals to use. If the amount of dissolved
oxygen in the water is too low, aquatic animals may die. Wastewater
and naturally occurring organic matter contain oxygen-demanding substances
that consume dissolved oxygen.
Domestic Wastewater (Sewage)
Human-generated wastewater that flows from homes, businesses, and industries.
Drainage Basin
The area of land from which water drains into a river; as, for example,
the Sacramento River Basin, in which all land area drains into the Sacramento
River. Also called "catchment area." "watershed." or "river basin."
Ecology
The study of the interrelationships of living organisms to one another
and to their surroundings.
Ecosystem
A community of living organisms interacting with one another and with
their physical environment, such as a rain forest, pond, or estuary.
Damage to any part of a complex system may affect the whole. A system
as complex as the Bay/Delta estuary can also be thought of as the sum
of many interconnected ecosystems such as the rivers, wetlands, and
bays. Ecosystem is thus a concept applied to communities of different
scale, signifying the interrelationships that must be considered.
Effluent
The liquid that flows out of a facility or household into a water body
or sewer system. For example, the treated liquid discharged by a wastewater
treatment plant is the plant's effluent.
Entrainment
Direct entrainment occurs when fish are pulled along with water into
a diversion structure because of strong currents created by pumps. Indirect
entrainment is caused by the transport of eggs or larve into less desirable
areas because of induced flows in channels surrounding diversion structures.
Entrapment Zone
An area in an estuary where seaward surface flows and landward bottom
currents cause suspended materials (including certain small plants and
animals) to accumulate. Particles that sink from the surface flows into
the bottom currents are carried upstream and toward the surface. Because
the entrapment zone concentrates phytoplankton and zooplankton, it is
an important area for some estuarine fish species (see Null Zone).
Environment
The sum of all external influences and conditions affecting the life
and development of an organism or ecological community.
Escapement
The number of adult salmon escaping harvest and returning to the spawning
grounds.
Estuary
A partially enclosed, coastal water body where ocean water is diluted
by out-flowing fresh water.
Estuary Basin
The land and waters within the boundaries of the immediate San Francisco
Bay watershed, Suisun Marsh, and the Sacramento-San Joaquin Delta.
Eutrophication
A condition in an aquatic ecosystem where high nutrient concentrations
stimulate blooms of blue-green algae. Algal decomposition may generate
odors and lower dissolved oxygen concentrations. Although eutrophication
is a natural process in the aging of lakes, it is accelerated by point
and nonpoint pollutant loads.
Evapotranspiration
The quantity of water transpired (given off) and evaporated from plant
tissue and surrounding soil surfaces.
Filter Feeder
An organism that feeds on microscopic food by filtering very large volumes
of water. Because of the amount of water filtered, these organisms may
tend to concentrate toxins. Filter feeders that live on bottom sediments
(e.g., clams and oysters) are particularly susceptible to contamination.
Gravitational Circulation
Net internal motions caused by horizontal density gradients. The denser
fluid flows along the bottom and lighter fluid along the surface in
an attempt to restore a stable vertical stratification. In the case
of the longitudinal salinity gradient, this produces a net landward
bottom current and compensating seaward current of fresher water at
the surface.
Ground Water
Underground water supplies stored in aquifers. Ground water is supplied
by rain which soaks into the ground and flows downward until it collects
at a point where the ground is not permeable. Ground water then usually
flows laterally toward a river, lake, or the ocean. Wells tap ground
water for consumptive uses.
Habitat
The sum of environmental conditions in a specific place that is occupied
by an organism, population, or community.
Historic Flows
The actual flows recorded during a specific period of time in the past.
Hydrocarbon
An organic compound composed of carbon and hydrogen; for example, petroleum
compounds.
Hydrodynamics
The motion and action of water and other liquids, i.e., the dynamics
of liquids, and the study thereof.
Hydrology
The science of water in nature: its properties, distribution, and behavior.
Intertidal Area
The area between high and low tide levels. The alternate wetting and
drying of this area makes it a transition between land and water and
creates special environmental conditions.
Lacustrine
A wetland classification that includes permanently flooded lakes and
reservoirs, intermittent lakes, and tidal lakes with ocean-derived salinities
below 5 ppt.
Land Use
The way land is developed and used in terms of the kinds of activities
allowed (agriculture, residences, industries, etc.) and the size of
buildings and structures permitted. Certain kinds of pollution problems
are often associated with particular land-use practices, such as sedimentation
from construction activities, oil and grease from streets and highways,
and pesticides from agricultural lands and urban parks.
Loading
The total amount of material entering a system from all sources.
Marsh
A wetland where the dominant vegetation is non-woody plants such as
grasses and sedges, as opposed to a swamp where the dominant vegetation
is woody plants like trees.
Natural Flows
The embayment and channel flows which existed at the time of the first
Spanish exploration of California, i.e., before the Gold Rush. Natural
flows were not measured.
Nonpoint Source Pollution
Pollution that enters water from dispersed and uncontrolled sources
(such as surface runoff) rather than through pipes. Nonpoint sources
(e.g., forest practices, agricultural practices, on-site sewage disposal,
and recreational boats) may contribute pathogens, suspended solids,
and toxicants. While individual sources may seem insignificant, the
cumulative effects of nonpoint source pollution can be significant.
Null Zone
The region in a partially- or well-mixed estuary where the residual
bottom currents are effectively zero. Landward of this point there is
a net seaward residual velocity along the bottom caused by river inflow;
seaward of the null zone, gravitational circulation produces a net landward
transport of denser more saline water along the bottom. The null zone
is the theoretical upstream boundary of the entrapment zone.
Nutrients
Essential chemicals needed by plants or animals for growth. If other
physical and chemical conditions are optimal, excessive amounts of nutrients
can lead to degradation of water quality by promoting excessive growth,
accumulation, and subsequent decay of plants, especially algae. Some
nutrients can be toxic to animals at high concentrations.
Palustrine
A wetland classification that includes all nontidal wetlands dominated
by trees, shrubs, peristent emergents, emergent mosses or lichen, and
all such wetlands that occur in tidal areas where salinities due to
ocean-derived salts are less than 5 ppt.
Pesticide
A general term used to describe chemical substances that are used to
destroy or control pest organisms. Pesticides include herbicides, insecticides,
algicides, fungicides, and others. Many of these substances are manufactured
and do not occur naturally in the environment. Others, such as pyrethrum,
are natural toxins which are extracted from plants and animals.
Photosynthesis
The process by which plants use light energy to make simple carbohydrates
from carbon dioxide and water.
Phytoplankton
Minute plants, usually algae, that live suspended in bodies of water
and that drift about because they cannot move by themselves or because
they are too small or too weak to swim effectively against a current.
Plankton
Small plants (phytoplankton) and animals (zooplankton) that are suspended
in the water and either drift with the currents or swim weakly.
Point Source
Any discernible, confined, and discrete conveyance, including but not
limited to any pipe, ditch, channel, tunnel, conduit, well, discrete
fissure, container, rolling stock, concentrated animal feeding operation,
or vessel or other floating craft, from which pollutants are or may
be discharged.
Pollutant
A substance that adversely alters the physical, chemical, or biological
properties of the environment. The term includes pathogens, toxic metals,
carcinogens, oxygen-demanding materials, and all other harmful substances.
With reference to nonpoint sources, the term is sometimes used to apply
to materials released in low concentrations from many activities which
collectively degrade water quality. As defined in the federal Clean
Water Act, pollutant means dredged spoil, solid waste, incinerator residue,
sewage, garbage, sewage sludge, munitions, chemical wastes, biological
materials, radioactive materials, heat, wrecked or discarded equipment,
rock, sand, cellar dirt, and industrial, municipal, and agricultural
waste discharged into water.
Polychlorinated Biphenyls (PCBs)
A group of manufactured chemicals including about 70 different but closely
related compounds made up of carbon, hydrogen, and chlorine. If released
to the environment they persist for long periods of time and can biomagnify
in food chains because they have no natural usage in the food web. PCBs
are suspected of causing cancer in humans. PCBs are an example of an
organic toxicant.
Polycyclic or Polynuclear Aromatic Hydrocarbons (PAHs)
A class of complex organic compounds, some of which are persistent and
cancer causing. These compounds are formed from the combustion of organic
material and are ubiquitous in the environment. PAHs are commonly formed
by forest fires and by the combustion of gasoline and other petroleum
products. They often reach the environment through atmospheric fallout
and highway runoff.
Pretreatment
The treatment of industrial wastewater to remove contaminants prior
to discharge into municipal sewage systems.
Primary Production
The production of plant matter (plant tissues) from carbon dioxide and
water through photosynthesis. By comparison, secondary production is
the production of animal tissue. Different plant communities are often
compared by measuring their rates of primary production.
Primary Treatment
A wastewater treatment method that uses settling, skimming, and chlorination
to remove solids, floating materials, and pathogens from wastewater.
Primary treatment typically removes about 35 percent of BOD and less
than half of the metals and toxic organic substances.
Salinity
The salt content of water, usually expressed as ppt (grams/liter), or
ppm (milligrams/liter).
Salinity Intrusion
The movement of salt water into a body of fresh water. It can occur
in either surface water or ground water bodies.
Salvage
Those fish diverted away from or removed from screens at intakes to
diversion structures and subsequently returned to a water body.
Secondary Treatment
A wastewater treatment method that usually involves the addition of
biological treatment to the settling, skimming, and disinfection provided
by primary treatment. Secondary treatment may remove up to 90 percent
of BOD and significantly more metals and toxic organic material than
primary treatment.
Sediment
Material suspended in or settling to the bottom of a liquid, such as
the sand and mud that make up much of the bottom of San Francisco Bay.
Semidiurnal Tide
A tidal variation consisting of two high and two low tides per lunar
day (24.84 hrs.). In San Francisco Bay, the cycle typically consists
of a high high followed by a low low, a low high, a high low and back
to a high high tide.
Shellfish
An aquatic animal, such as a mollusk (clams and snails) or crustacean
(crabs and shrimp), having a shell or shell-like exoskeleton.
Silviculture
Practices associated with forest development.
Smolt
An anadromous fish that is physiologically ready to undergo the transition
from fresh to salt water; age varies depending on species and environmental
conditions.
Source Control
A practice, method, or technology that is used to reduce pollution from
a source; for example, best management practices or end-of-pipe treatment.
Spawning
The deposit of eggs (or roe) by fish and other aquatic life.
Species Diversity
The number of species within a community of organisms. Areas of high
diversity are characterized by a great variety of species. A biological
community with high diversity is better capable of withstanding environmental
disturbances. Pollution tends to reduce biological diversity.
Stormwater
Water that is generated by rainfall and is often routed into drainage
systems in order to prevent flooding.
Striped Bass Index (SBI)
An index of the number of young bass which have survived through their
first summer. Young bass are sampled with nets which are most efficient
for fish about 1.5 inches in length. Sampling methods are consistent
(with respect to location, frequency, technique, etc.) so that the number
of young striped bass caught may be compared with the catch at various
locations year to year. The number of young bass caught by the standard
sampling methods allows statistical treatment of data to estimate the
abundance of young striped bass and to correlate changes in the number
caught with changes in environmental factors.
Subtidal
Below the ebb and flow of the tide. Used to refer to the marine environment
below mean lower low tide.
Suspended Solids
Organic or inorganic particles that are suspended in and carried by
the water. The term includes sand, mud, and clay particles as well as
solids in wastewater.
Teratogenic
Causing birth defects.
Total Suspended Solids (TSS)
Particles of all sizes that are suspended in a measured volume of water.
TSS reduce light penetration in the water column, can clog the gills
of fish and invertebrates, and are often associated with toxic pollutants
because organic materials and metals tend to bind to particles.
Toxic
Poisonous, carcinogenic, or otherwise directly harmful to life.
Transpiration
The process in which plant tissues give off water vapor to the atmosphere
as an essential physiological process.
Treatment
Chemical, biological, or mechanical procedures applied to an industrial
or municipal discharge or to other sources to remove, reduce, or neutralize
pollutants.
Turbidity
A measure of the amount of material suspended in the water. Increasing
the turbidity of the water decreases the amount of light that penetrates
the water column. Sustained, high levels of turbidity are harmful to
aquatic life.
Unimpaired Flow
The embayment and channel flows which would exist in the absence of
upstream impoundments and diversions of rainfall or snowmelt runoff,
but in the presence of existing channel configurations, both upstream
and in the Delta.
Water Column
The water in a lake, estuary, or ocean which extends from the bottom
sediments to the water surface. The water column contains dissolved
and particulate matter and is the habitat for plankton, fish, and marine
mammals.
Water Quality
A term used to describe the chemical, physical, and biological characteristics
of water, usually with regard to its suitability for a particular purpose.
Water Year
A continuous 12-month period for which hydrologic records are compiled
and summarized. In California. the water year be~ins October 1.
Watershed
The geographic region within which water drains into a particular river,
stream, or body of water. A watershed includes hills, bottom land, and
the body of water into which the land drains. Watershed boundaries are
defined by the ridges of separating watersheds. The Bay/Delta estuary's
watersheds include those of the estuary basin and the Central Valley.
Wetlands
Habitats where the influence of surface- or groundwater has resulted
in development of plant or animal communities adapted to aquatic or
intermittently wet conditions. Wetlands include tidal flats, shallow
subtidal areas, swamps, marshes, wet meadows, bogs, and similar areas.
Zooplankton
Free-floating aquatic animals found in most water bodies. Zooplankton
range in size from microscopic protozoans to large jellyfish. In the
estuary, they are an important food source for many species of fish
and other organisms.
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Site created and hosted by ABAG
Last updated July 15, 2004
Michael Smith, Regional Planner