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Abbreviation Description
AA chemistry - atomic absorption, a spectrophotometric instrumental method used to analyze for trace elements
AAS chemistry - atomic absorption spectrophotometer
absorption chemistry the atomic process whereby an atom or molecule absorbs energy at a given wavelength, causing an electron to move to a higher-energy orbital; the opposite of emission; this term should not be confused with adsorption.
accuracy statistics/quality assurance - the closeness of a measured value to the true value
acre English unit for land area (see unit conversion factors)
acre-ft English volume unit for water, 1 acre-ft = 1,233.5 m3 = 325,851 gallons, (see unit conversion factors)
ACS American Chemical Society
activity chemistry - the concentration of a specific chemical species in moles per liter that has been adjusted for equilibrium conditions such as ionic strength, temperature, and pressure
adipose, adipose fin anatomy - fatty tissue; biology - a small fin without spines or rays on the fish back between the dorsal and caudal fins
adsorption chemistry - the process whereby a chemical compound attaches to a surface; adsorption may involve several attractive forces, including van der Waal's forces, electrostatic attraction, or chemical bonding; this term should not be confused with absorption.
aerobic biology/chemistry - with oxygen
AFS American Fisheries Society
Ag chemistry - the element silver
air bladder biology - the organ that allows a fish to maintain bouyancy and equilibrium in the water
Al chemistry - the element aluminum
alevin biology - fish fry still having visible yolk sac, especially for salmonids
algae biology - microscopic aquatic plants that contain chlorophyll
alkalinity chemistry - the acid neutralizing components in water, usually carbonate (CO32-), bicarbonate (HCO3-) and hydroxide (OH-); often reported in mg/L as CaCO3
allochthonous biology - pertaining to organic materials produced outside an aquatic system
α-emission physics - alpha emission, high energy helium nuclei (2 protons + 2 neutrons) emitted during radioactive alpha decay
α, α-error Greek letter alpha; statistics - the confidence level; the risk of rejecting a true null hypothesis; type I error or rejection error; the probability of a false-positive error
alluvium biology/geology - materials and sediment deposited by flowing water
amu chemistry - atomic mass units
anadromous biology - a fish or other organism living its adult lifestage in salt water, returning to freshwater for spawning
anaerobic biology/chemistry - without oxygen
anal fin biology - rear fin protrouding from bottom of fish
analyte chemistry - the chemical compound or constituent being detected or analyzed
anions chemistry - negatively charged ions, usually HCO3-, CO32-, SO42-, and Cl-
ANOVA statistics - analysis of variance, a method for testing equality of means between several variables or determining the significance of estimated parameters in a regression model
anoxic biology - an environment without oxygen; synonym for anaerobic
ANSI American National Standards Institute
anterior biology/anatomy - on the front or forward part of an anatomical structure
APHA American Public Health Association
approach velocity hydraulic engineering - the water velocity measured perpendicular to and approximately 3 in from a louver face or positive barrier screen
As chemistry - the element arsenic
ASCE American Society of Civil Engineers
ASQC American Society for Quality Control
ASTM American Society for Testing and Materials
atm atmosphere, common unit for atmospheric pressure, equaling atmospheric pressure at mean sea level (see unit conversion factors)
autochthonous biology - pertaining to organic materials produced within an aquatic system
AWWA American Water Works Association
B chemistry - the element boron
Ba chemistry - the element barium
bar non SI atmospheric pressure unit, 1 bar = 105 N/m2 (see unit conversion factors)
BDL chemistry - below detection limit
behavioral device hydraulic engineering/biology - a fish control device, such as a crowder, screen, or louver array, that requires fish to change their locomotor behavior to avoid entrainment
belly biology - bottom of fish between pelvic and anal fins
benthic biology - associated with sediment-water interface in water bodies
β-emission radiochemistry - high energy electrons emitted during radioactive decay
β, β-error Greek letter beta; statistics - the error of accepting a false null hypothesis, also called type II error, or acceptance error; the probability of a false-negative error
bias statistics/quality assurance - a consistent deviation of measured values from the true value caused by a systematic error
bioassay biology/toxicology - an experiment where multiple populations of organisms are exposed to a toxic chemical at zero concentration (the control group) and a series of increasing concentrations (exposure groups) to determine the toxicity of the chemical
biological opinion regulatory - an advisory issued under the Endangered Species Act (ESA) by USFWS or NMFS to federal agencies considering actions that may affect endangered species
biomass biology - the weight of biological matter in a system, usually expressed as weight of carbon per unit area (g/m2) or weight of carbon per volume (mg/m3)
blind chemistry/quality assurance - a certified check sample or duplicate sample submitted to a lab disguised as another different sample
BOD chemistry - biological oxygen demand; the degree to which algae and organisms in a natural water sample will deplete dissolved oxygen in a given length of time
body depth biology - distance from top to bottom of fish excluding fins
Bq Becquerel, SI unit for radioactive decay, 1 Bq = 1 radioactive disintegration per second
Br, Br- chemistry - the element bromine; the bromide ion
breast biology/anatomy bottom of fish between the opercle and pelvic fin
burst speed fish biology - an extreme speed motion that can only be maintained for short periods on the order of seconds; also called darting speed; usually associated with predation and predator avoidance
bypass hydraulic engineering - the fish diversion conduits located at intervals along the primary louver structure at the Tracy Fish Collection Facility. See schematic diagram.
bypass ratio hydraulic engineering - the ratio of the bypass velocity (ft/s) to the channel velocity (ft/s), calculated by dividing the bypass velocity by the channel velocity
C chemistry - the element carbon; coulomb, SI unit for electric charge
Ca, Ca2+ chemistry - the element calcium, or calcium ion
CALFED CALifornia - FEDeral Bay Delta Program, now called the Bay-Delta Authority
candidate species regulatory - species being considered for protection under the Endangered Species Act by inclusion in the List of Endangered and Threatened Species
carcinogen biology - a chemical or influence that causes cancer
carnivorous biology - meat eating
CAS chemistry - Chemical Abstracts Service; an technical abstracting service for the chemistry literature sponsored by the American Chemical Society; a standard reference number for chemicals established by CAS
catabolism biology/biochemistry - the process whereby large molecules are broken down; decomposition
catadromous biology - a fish or other organism living its adult lifestage in fresh water, returning to salt water for spawning
cations chemistry - positively charged ions, usually Ca2+, Mg2+, Na+, and K+
caudal, caudal fin biology/anatomy - located on the tail; the tail fin
Cd chemistry - the element cadmium
CDFG California Department of Fish and Game
CDWR California Department of Water Resources
Celsius, °C SI metric temperature scale with 0° set to the freezing point of water, and 100° to the boiling point of water at 1 atm pressure; formerly called centigrade (see unit conversion factors)
centrarchid biology - fish classified in family Centrarchidae, including bluegill, crappies, sunfish, and black basses
CERCLA Comprehensive Environmental Response, Compensation and Liability Act, Public Law PL 96-510, 40 CFR 300, 1980; the federal environmental law that regulates cleanup of hazardous waste sites; the Superfund program
cfs, ft3/s cubic feet per second, flow unit, 1.00 ft3/s = 28.317 liters per second, (see unit conversion factors)
CH4 chemistry - methane gas, carbon in the -IV oxidation state
cheek biology/anatomy - side of fish head forward of the preopercle below the eye
Χ2, chi squared test statistics - a common significance test based on the Χ2 statistic, for comparing observed variance to theoretical variance expected for a normal distribution, or the goodness of fit between observed and hypothetical frequencies
chlorophyll biochemistry - the green pigment in most plants
Ci physics - Curie, a non-SI unit for radioactive disintegrations, equal to 3.7 x 1010 becquerels (Bq, or disintegrations per second) (see unit conversion factors)
CIPS biology - continuous icthyhion pump sampler, an automated sampling device to collect fish eggs and larvae
Cl, Cl- chemistry - the element chlorine, or the chloride ion
Co chemistry - the element cobalt
CO2 chemistry - carbon dioxide gas
CO32- chemistry - carbonate, or carbonate ion
COD chemistry - chemical oxygen demand
COE or USACE U.S. Army Corps of Engineers
colorimetric chemistry - a spectrophotometric analytical method that uses a chemical to react with the analyte to form a colored compound. The intensity of the colored compound is related to concentration.
composite sample chemistry - a combined sample containing subsamples collected from different locations, depths, or times
condition factor biology - an indicator of fish health, calculated as K =( W/L3) x 100, where W = wet weight in grams, and L = fork length in centimeters
confidence interval, CI statistics - a probability-based estimate of the standard deviation; the interval between the upper and lower confidence limits; for normal data distributions, confidence limits may be calculated using the t-distribution value at a given confidence level, or α
-COOH, -COO- chemistry - the carboxylic acid functional group denoting an organic acid; the carboxylate ion
cortisol biochemistry - a hormone produced by vertebrate organisms when exposed to stress
Cr chemistry - the element chromium
critical habitat regulatory - the areas and habitats identified under the Endangered Species Act that must be protected for a given endangered species to recover or survive
crowder hydraulic engineering - a moveable porous wall or screen used to move fish in a channel
cruising speed fish biology - a speed that can be maintained for periods of time on the order of hours
CRWQB California Regional Water Quality Board
Cu chemistry - the element copper
CVAA chemistry - cold vapor atomic absorption
CVAFS chemistry - cold vapor atomic fluoresence spectrophotometry
CVO Central Valley Operations Office, Bureau of Reclamation, Sacramento, California
CVP Central Valley Project
CVPIA Central Valley Project Improvement Act of 1992
CWA Clean Water Act, Public Law PL 92-500, 1972, 40 CFR 100-140, and 400-470; the federal environmental law regulating pollutant discharges into surface waters
cyprinid biology - fish classified in family Cyprinidae including minnows, carps, chubs, splittails, and daces
degrees of freedom, df statistics - the number of independent data elements needed to calculate a statistical estimate or parameter in a model, usually listed as a column in an ANOVA table; means and other parameter estimates are usually reported with the associated df, usually calculated as (n - 1) or (n - 2)
delta the area where a river empties into a bay or ocean; in California, the Sacramento-San Joaquin Delta region of the Central Valley from Vernalis to Sacramento
dependent variable statistics - a variable that is predicted by other variables called independent variables; the y-variable in a y = f(x) model
detritus biology/limnology - nonliving particulate matter
diatom biology - symmetrical algae having siliceous cell walls
diel biology - a 24-h period, referring to a daily pattern or behavior
dissolved chemistry - an operationally defined term applied to water analysis results, usually meaning that the sample is filtered through a 0.45-µm pore-size membrane filter before analysis
distribution statistics - the characterization of a variable based on a histogram that shows frequency (number of observations) vs. observed values classified into cells based on ranked data value ranges. Common data distributions include the symmetrical normal (bell-curve), and the skewed log-normal.
diversion, diversion dam engineering - a structure that diverts water from a river or other water body; a dam that partially blocks a river or stream to allow diversion of water into canals or other conveyance structures
DL chemistry - detection limit
DMC Delta-Mendota Canal
DO chemistry - dissolved oxygen, mg/L
DOC chemistry - dissolved organic carbon
dorsal biology/anatomy - on the upper surface
double layer chemistry/physics - the electrical double layer, a region of static charge at the surface of an ion in solution or a particle suspended in water; such as the surface charge field surrounding a dissolved ion or clay particle suspended in water
EA regulatory - Environmental Assessment, a preliminary study of the environmental effects of a proposed development or construction project that is required by the National Environmental Policy Act (NEPA). The EA is the initial disclosure of environmental impact and economic cost to benefit analysis. If concerned parties dispute the EA findings, a more involved Environmental Impact Statement (EIS) may be required.
E&L biology - egg and larvae; generally referring to fish egg and larvae collected using tow nets or continuous pumped samplers; see CIPS
EC chemistry - electrical conductivity, measured in microsiemens per centimeter, µS/cm; also electron capture detector, a detector on a gas chromatograph that is sensitive to halogens in organic compounds
effective screen area hydraulic engineering - the cross-sectional area containing void space where water may flow through a screen or other porous barrier structure
egg biology - female gamete; on this site usually refers to fish egg
Eh chemistry - redox or oxidation-reduction potential, measured in millivolts, mV
EIS regulatory - Environmental Impact Statement; a comprehensive technical report and disclosure of the environmental impacts and costs of a proposed construction project, development, or alteration in use of land or water resources, required by the National Environmental Policy Act (NEPA)
electroneutrality chemistry - a property of natural waters where positive ions (sum of cations) and negative ions (sum of anions) have equal concentrations (in meq/L); this principle can be used to independently check analysis results for major ions; see ion balance (in unit conversion factors)
emission chemistry - an atomic process whereby an atom or molecule emits photons of a given wavelength when external energy is applied; the opposite of absorption; a spectrophotometric analytical method based on emission, such as ICP-ES, spark spectrometry, or flame photometry; water quality - a pollutant that is released into the environment
endangered species regulatory - a class of species protected under the Endangered Species Act, (ESA); species in imminent danger of extinction
endocrine biology - relating to the system of glands in vertebrates that secrete hormones to regulate metabolism and reproduction
endocrine disruptor chemistry - a chemical compound in the environment suspected of imitating hormones or blocking the proper functioning of hormones in organisms
entrainment transporting fish out of their native ecosystem by way of water passed through a conduit, penstock or diversion at dams or irrigation canals
EPA U.S. Environmental Protection Agency
epiphyton biology - plants that grow on other plants or nonliving structures
EPRI Electric Power Research Institute
equivalent chemistry - a chemical concentration unit based on reactivity, equal to the molar weight divided by the valence of the compound or ion
ESA regulatory - Endangered Species Act, PL 93-205, 16 USC 1531, 1988, the federal law that identifies and protects endangered and threatened plant and animal species
estuarine biology - pertaining to an estuary
estuary biology - aquatic transition zone where fresh water and salt water mix, influenced by tides
exotic species biology - species not native or indigenous to an ecosystem; an invasive species
extrapolation estimating a data value that lies below or above the measured data range using a regression equation or graphical method
F, F- chemistry - the element fluorine, or the fluoride ion
F, F test statistics - a statistical test based on ratios of sums of squares and other statistics, used to test equality of means in analysis of variance, and significance of parameter estimates in regression analysis; also called a variance ratio test
Fahrenheit, °F Non-SI temperature scale with 32° set to the freezing point of water, and 212° to the boiling point of water (see unit conversion factors)
fatty acid biochemistry - long-chain hydrocarbons in cells that have a terminal hydroxyllic acid functional group (-COOH). Fatty acids form most adipose tissue and are important components of cell walls and other membranes.
Fe chemistry - the element iron
Fe2+ chemistry - the ferrous ion, a reduced form of iron in the +II oxidation state; the stable form of iron found in anaerobic waters and sediments
Fe3+ chemistry - the ferric ion, an oxidized form of iron in the +III oxidation state; the stable form of iron in oxygenated waters
FIA chemistry - flow injection analyzer, a general term for instruments that automate colorimetric analyses
FID chemistry - flame ionization detector, on a GC instrument
fingerling fish biology - a small fish around the size of a human finger, approximately 6 cm
flume hydraulic engineering - an artificial water channel for investigating hydraulic structure designs
fork length, FL biology - the length of a fish measured from the snout to the fork in the tail along the lateral line
Froude number hydraulic engineering - the ratio of inertial forces to gravitational forces in flow (V/(gL)½). When the Froude number is less than one, the flow is tranquil. When the Froude number is greater than one, the flow is rapid. When the Froude number is equal to one, the flow is critical
fry biology - a young fish with developed fins
FTU chemistry - formazin turbidity units
fulvic acid, fulvic materials chemistry - a heterogeneous and polydisperse class of organic compounds with molecular weights from 600 to 2,000 amu, found in natural soil and water environments, that includes fatty acids, proteins, polysaccharides, and their hydrolysis products. Fulvic materials account for most of the DOC in natural waters. Like humic materials, fulvic materials are formed by the decomposition of living matter, but are usually more soluble than the higher molecular weight humic materials
FWS, USFWS U.S. Department of the Interior - Fish and Wildlife Service
g gram, SI mass unit, (see unit conversion factors)
G SI unit prefix for giga, or 109
γ-emission Greek letter gamma; physics - very high energy ionizing radiation released during radioactive decay, or nuclear fission or fusion
GC chemistry - gas chromatograph
GC-MS chemistry - gas chromatograph/mass spectrometer
GFAA chemistry - graphite furnace atomic absorption
gill biology - the breathing organ of fish
Gy Gray, SI unit for radiation dosage, 1 Gy = 1 J/kg (see unit conversion factors)
H0 statistics - the null hypothesis being tested, usually that the means of two samples are equal
H1 statistics - the alternate hypothesis being tested, usually that the means of two samples are unequal
ha hectare, SI area unit, 1 ha = 1.00 X 104 m2 (see unit conversion factors)
halogen chemistry - a class of elements in Group VIIA (IUPAC group 7B, or 17) of the periodic table, including F, Cl, Br, and I
halogenated chemistry - referring to organic compounds where a halogen (Cl, F, Br) has bonded to a carbon atom
hardness chemistry - the sum of divalent ions in a water sample, usually calculated as calcium + magnesium, and often reported in mg/L as CaCO3
HCO3- chemistry - bicarbonate, or bicarbonate ion, the dominant form of alkalinity in most natural surface waters
head hydrology - hydrostatic potential, or pressure difference between two water surfaces or depths, usually expressed in feet or inches of water
head differential hydraulic engineering - water pressure difference across the surface of a screen, louver, or other positive barrier structure, usually measured in inches of water
head length biology - length from opercle to tip of snout
hepatotoxin biology/toxicology - a toxic compound or agent that damages liver tissue or interferes with normal liver biochemistry
herbivorous biology - plant eating
heterogeneous chemistry - poorly mixed and having different phases, such as a solid dispersed nonuniformly in a liquid, or as with soil composed of many minerals in a random mixture
heteroscedasticity statistics - a property where distributions have unequal variances; an assumption violation for least squares regression analysis where the residuals are systematically unequal or correlated over the range of observations
hexavalent chromium chemistry - a toxic form of chromium; chromium in the +VI oxidation state, as in CrO42- (chromate ion) or Cr2O72- (dichromate ion)
Hg chemistry - the element mercury
histogram statistics - a graph of ranked and grouped data that shows the distributional properties of the variable; a graph of number of observations within ranked groups (called cells, based on an arbitrary range of data values) vs. value
homogeneous chemistry - completely and uniformly mixed, as with dissolved constituents in water
homoscedasticity statistics - the property of equal variance among distributions; an assumption for least squares regression analysis where the distribution of residuals is uniform and uncorrelated over the range of observations
humic acid, humic materials chemistry - a heterogeneous and polydisperse class of high average molecular weight (greater than 2,500 amu) organic compounds found in natural soil and water environments that includes fatty acids, proteins, polysaccharides and their hydrolysis products. Humic materials are formed by the decomposition of living matter, and are usually less soluble than the lower molecular weight fulvic materials
H2S chemistry - hydrogen sulfide, a gas that smells like rotten eggs, usually associated with stagnant water and prolonged anaerobic conditions
hydrolysis chemistry - a reaction, usually in aqueous solution, in which hydroxide reacts with C-C bonds causing cleavage (lysis) of molecules; a common reaction that breaks down organic compounds in natural waters, especially at higher pH
hyporheic biology - pertaining to benthic environments in streams including the porous subflow zone and the oxic-anoxic boundary
Hz Hertz, SI unit for frequency; formerly cycles per second
I chemistry - the element iodine  
IC chemistry - ion chromatograph
ichthyology the study of fish
ICP-ES chemistry - inductively-coupled plasma - emisssion spectrograph
ICP-MS chemistry - inductively-coupled plasma - mass spectrometer  
IDL chemistry - instrument detection limit
IEC International Electrotechnical Committee
IEP Interagency Ecological Program
in English length unit, 1 inch = 2.54 cm, (see unit conversion factors)
incidental take biology/regulatory - threatened, endangered, or protected fish or other wildlife entrained or collected incidentally during otherwise lawful activities conducted by government or private organizations
independent variable statistics - a variable in a regression model used to predict the dependent variable; apredictor variable; the x-variable in a y = f(x) model
interpolationestimating a data value that lies between two nearby data values using an average or a graphical method  
invasive species biology/regulatory - a non-native species that reduces species diversity when introduced into an ecosystem
invertebrate biology - an animal lacking a backbone
ion chemistry - an element or molecule dissolved in water with a net positive or negative electrical charge
ion balance chemistry - a percentage calculation used to check major ions data that compares cations to anions; values near zero suggest that the analysis results are accurate and confirm electroneutrality in the water sample (see unit conversion factors)
ISO International Organization for Standardization
IUPAC International Association of Pure and Applied Chemistry, the organization establishing standardized atomic weights and chemical constants
J joules, SI unit for energy, work or quantity of heat, 1 J = 1 N-m (see unit conversion factors); regulatory - EPA data validation code for "estimated"
juvenile biology - lifestage before adult
k SI unit prefix kilo, or 103
K, K+ chemistry - the element potassium, or potassium ion
Keq, K chemistry - the equilibrium constant for a given balanced chemical reaction, based on the stoichiometry of the reactions and ratio of product concentrations to reactant concentrations at chemical equilibrium
Kelvin, °K chemistry/physics - thermodynamic temperature scale with 273° set to the freezing point of water, 373° to the boiling point of water, and 0 °K called absolute zero (see unit conversion factors)
kg kilogram, SI mass unit (see unit conversion factors)
Kolmogorov-Smirnov test statistics - significance test for degree or goodness of fit between a hypothetical and observed data distribution; a test for the equality of two observed distribution functions
Kruskal-Wallis test statistics - a distribution-free test for the equality of two observed distributions, based on the Wilcoxon-Mann-Whitney test
L liter, SI volume unit (see unit conversion factors)
lacustrine biology - pertaining to lakes
λ Greek letter lambda; physics - symbol for wavelength
lamellae biology - the small vaned structures on gills that facilitate oxygen uptake
laminar flow hydraulic engineering - flow that is slow and uniform
larvae biology - newborn fish; first fish lifestage after hatching from egg
lat/long latitude/longitude
lateral line biology/anatomy - a canal running down the side of the fish containing nerves and sensory organs that detect pressure and electrical fields
LC50 toxicology - lethal concentration that kills 50 percent of the test organisms within the exposure period of the bioassay
LD50 toxicology - lethal dosage that kills 50 percent of the test organisms within the exposure period of the bioassay
lentic biology/limnology - pertaining to still water
limnetic biology/limnology - associated with a lake environment
limnology the study of the biology, chemistry, morphology, and hydrodynamics of lakes
listed species regulatory - plant and animal species designated as threatened or endangered under the Endangered Species Act (ESA)
littoral biology/limnology - shallow lake or estuarine enviroment that supports aquatic plants
LOD chemistry - limit of detection, a statistically based estimate of the lowest statistically valid measurement concentration for an instrument or analytical method
LOQ chemistry - limit of quantitation, a statistically based estimate, equal to three times the limit of detection (LOD)
log(AP/(KT) chemistry - see saturation index
lotic biology/limnology - flowing water environment as in streams and rivers
louver hydraulic engineering - a structure containing an array of vertical or horizontal vanes used to control fish movement in flowing water
LR statistics - linear regression
m meter, SI length unit (see unit conversion factors); also SI unit prefix for milli, or 10-3
M chemistry - molarity, moles per liter ( see unit conversion factors); also SI unit prefix for mega, or 106
m/s meters per second, SI velocity unit (see unit conversion factors)
macrophyte biology - any plant visible to the unaided eye
major ions chemistry - higher concentration elements dissolved in water, usually: Ca2+, Mg2+, Na+, K+, CO32-, HCO3-, SO42-, and Cl-
mandible biology/anatomy - lower jaw
marsh biology - wetland, swamp
matrix chemistry - the sum of all chemical components in the sample besides the analyte being tested
MCL Maximum Contaminant Level; federal regulated concentrations defined under the Safe Drinking Water Act and adopted by CERCLA for Superfund site cleanups
MDL chemistry - method detection limit
mean statistics - the arithmetic average, an estimate of central tendency applied to variables having normal distributions
median statistics - an estimate of central tendency that does not depend on the distribution of the data; the middle value in a data set that has been ranked (arranged, or sorted) from minimum value to maximum value; the 50th percentile
medium diversion regulatory - a water diversion structure defined by the State of California to channel flows from 15 to 250 ft3/s (cfs)
Me-Hg chemistry - methylmercury, the methylmercuric ion, CH3-Hg+
meq/L chemistry - concentration unit milliequivalents per liter (see unit conversion factors)
metabolism biochemistry - the biochemical process whereby organisms convert food and nutrients into energy for survival and reproduction
metazoa biology - multicellular animals
µ Greek letter Mu; statistics - the population mean; SI metric unit prefix for micro, or 10-6
µeq/L chemistry - microequivalents per liter, 10-6 equivalents per liter (see unit conversion factors)
µg microgram, SI mass unit, 1 µg = 10-6 g (see unit conversion factors)
µg/kg chemistry - micrograms per kilogram (1,000 g), an SI concentration unit applied to solid samples and liquid samples with high salinity (see unit conversion factors)
µg/L chemistry - micrograms (10-6 g) per liter, SI concentration unit (see unit conversion factors)
µm micrometer, or micron (10-6 m), SI length unit (see unit conversion factors)
µS/cm chemistry - microsiemens per square centimeter, an SI unit for electrical conductivity (see unit conversion factors)
mg milligram, SI mass unit, 1 mg = 10-3 g (see unit conversion factors)
mg/kg chemistry - milligrams per kilogram (1,000 g), an SI concentration unit usually applied to solid samples and liquid samples with high salinity or density (see unit conversion factors)
mg/L chemistry - milligrams per liter, SI concentration unit (see unit conversion factors)
milt biology - the milky fluid containing sperm secreted by male fish during spawning
MINTEQ, MINTEQA2 chemistry - a computer chemical equilibrium model developed by EPA that calculates all the possible chemical species in solution based on equilibrium constants for the competing reactions; also calculates mineral saturation indices based on concentrations entered into the model
mL milliliter, SI volume unit, 1,000 mL = 1.000 L (see unit conversion factors)
MLR statistics - multiple linear regression - a regression model that assumes multiple independent variables (xi) that interact in only an additive or subtractive way (thus linear) to predict a dependent variable, y
mm millimeter (10-3 m), SI length unit (see unit conversion factors)
Mn chemistry - the element manganese
Mo chemistry - the element molybdenum
modulus mathematics - the absolute value of a number; engineering - a coefficient or numerical value that expresses the degree of a property associated with a body or substance
mol/L chemistry - moles per liter (see unit conversion factors)
molal chemistry - moles per 1,000 g of solution (see unit conversion factors)
mole chemistry - a concentration unit equal to the mass of Avogadro's number (6.023 X 1023) of molecules of a chemical compound, or atoms of an element
morbid, morbidity biology - lack of vitality, indicative of sickness or injury
mortality biology - death
MP Mid-Pacific Region, Bureau of Reclamation
mucous, mucus biology - a slippery polysaccharide and protein mixture secreted by fish that covers all surfaces exposed to the environment
mutagenic biology/toxicology - referring to a chemical compound or environmental influence that causes cell mutations
mV millivolt, SI voltage unit (see unit conversion factors)
mw chemistry - molecular weight (see unit conversion factors)
N chemistry - the element nitrogen; chemistry - normality, expressed in equivalents/liter; Newton, SI unit for force, 1.0 N = 1.0 kg-m/s2 (see unit conversion factors)
n SI unit prefix nano, or 10-9; statistics - number of samples, cases, or observations (also n)
N/m2 Newtons per square meter, SI unit for pressure (see unit conversion factors)
Na, Na+ chemistry - the element sodium, or sodium ion
nape biology - top of fish head from snout to dorsal fin
native regulatory - a species naturally occuring in an ecosystem; an indigeneous species not introduced by humans
NCDC National Climate Data Center, NOAA
ND chemistry - not detected
NEPA regulatory - the National Environmental Policy Act of 1969, 42 U.S.C §§ 4321-4370c; the federal environmental law that established the Council on Environmental Quality and requires federal agencies to formally consider environmental impacts of planned actions or decisions potentially affecting the quality of the human environment
ng nanogram, SI mass unit, 1 ng = 10-9 g (see unit conversion factors)
ng/kg chemistry - nanograms (10-9 g) per kilogram (1,000 g), an SI concentration unit applied to solid samples and liquid samples with high salinity (see unit conversion factors)
ng/L chemistry - nanograms per liter, SI concentration unit (see unit conversion factors)
NH3 chemistry - ammonia; nitrogen in the -III oxidation state
NH4+ chemistry - ammonium ion
Ni chemistry - the element nickel
NIH U.S. Department of Health, Education, and Welfare - National Institutes of Health
NIST U.S. Department of Commerce - National Institute of Standards and Technology; formerly the National Bureau of Standards
NMFS NOAA - National Marine Fisheries Service
NO2- chemistry - nitrite, or nitrite ion, nitrogen in the +III oxidation state
NO3- chemistry - nitrate, or nitrate ion, nitrogen in the +V oxidation state
NO3+NO2 chemistry - nitrate plus nitrite
NOAA U.S. Department of Commerce - National Oceanic and Atmospheric Administration
non-native regulatory - a species introduced by human activity into an ecosystem; an exotic or invasive species
nonparametic statistics - a statistic or statistical analysis based on data rank; a statistic or estimate that does not depend on the data distribution
normal statistics - a data distribution having symmetrical tails; the "bell-curve"
NPDES National Pollution Discharge and Elimination System; the permitting system for regulating polution discharge point sources, administered by the states based on national guidelines developed under the Clean Water Act
NSF National Science Foundation
NTIS U.S Department of Commerce - National Technical Information Service
NTU chemistry - nephelometric turbidity units (see unit conversion factors)
nutrients chemistry - a term referring to all nitrogen and phosphorus species, usually includes total-P, ortho-P, TKN, NO3+NO2, NH3
OH- chemistry - hydroxide, or hydroxide ion
omnivorous biology - plant and meat eating
o-P, ortho-P chemistry - orthophosphate
opercle, operculum biology - the bony or cartiligenous flap covering the gills
organic chemistry - referring to compounds containing carbon, excluding inorganic carbon as in carbonates
Organic-N chemistry - nitrogen bound to organic matter in water, calculated as TKN - NH3
ORP chemistry - oxidation-reduction potential; Eh
otolith biology - small calcareous particles found in the inner ear of vertebrates
oxic biology - an environment containing oxygen; synonym for aerobic
oxidizing chemistry - a chemical environment where oxygen is present and/or excess electrons are unavailable; in natural waters, an aerobic environment where dissolved oxygen is present and compounds may undergo oxidation from a lower oxidation state to a higher oxidation state, such as ferrous iron, Fe2+ (Fe in the +II oxidation or valencestate), being oxidized to ferric iron, Fe3+ (Fe in the +III oxidation or valence state); a natural water environment with positive Eh
p SI unit prefix for pico, or 10-12
P chemistry - the element phosphorus; statistics - probability
Pa Pascal - SI unit for pressure (see unit conversion factors)
parameter statistics - a coefficient or constant estimated by a regression or multivariate analysis
parametric statistics - a statistic or statistical analysis based on the least-squares minimization method that assumes data are normally distributed
partial pressure chemistry - the pressure associated with a gas in a mixture of gases, based on the mole fraction of the gas, measured in atm, Pa, or mm of Hg (torr) (see unit conversion factors)
Pb chemistry - the element lead
pCi/cm2 radiochemistry - picocuries per square centimeter, non-SI unit used in water quality for measuring radioactive emissions, 1.0 curie = 3.7 x 1010 radioactive disintegrations per second (see unit conversion factors)
pCO2 chemistry - the partial pressure of carbon dioxide, measured in atm, Pa, or mm of Hg (torr) (see unit conversion factors)
pectoral, pectoral fin biology - protruding from the side; the paired fins located behind the opercle on the side of the fish
peduncle biology - the rear, side-facing, portion of the fish body before the caudal fin
pelagic biology - referring to organisms and habitats in open oceanic environments
pelvic fins biology - the forward paired fins protruding from bottom of fish
Percent R, %R chemistry - percent recovery, in general, (observed value)÷(true value) X 100
periphyton biology - sessile organisms covering surfaces in freshwater aquatic environments
pH chemistry - hydrogen ion concentration as activity, defined as the negative logarithm (base 10) of the hydrogen ion activity; an indicator of the acidity or alkalinity of water that follows a unitless scale (called s.u., or standard units) of 0 to 14
pharyngeal teeth biology/anatomy - teeth associated with the pharynx
phreatic surface hydrology - the surface of groundwater in an aquifer or earth-fill dam
PHREEQE chemistry - a computer chemical equilibrium model developed by the USGS that calculates all the possible chemical species in solution based on equilibrium constants for competing reactions based on concentrations and reactions entered into the model
phytoplankton biology - free-floating microscopic aquatic plants
plankton biology - free floating microscopic aquatic plants and animals
pO2 chemistry - the partial pressure of oxygen, measured in atm, Pa, or mm of Hg (torr) (see unit conversion factors)
PO43- chemistry - orthophosphate, phosphate, or phosphate ion
pOH chemistry - hydroxide ion concentration as activity, defined as the negative logarithm (base 10) of the hydroxide ion activity; an indicator of the acidity or alkalinity of water that follows a unitless scale of 0 to 14; pOH = 14 - pH
polydisperse chemistry - having a range of molecular weights; applied to classes of compounds with a distribution of molecular weights, such humic or fulvic materials
polysaccharide biochemistry - long-chain biological molecules formed from repeating units of various sugar molecules
porosity hydraulic engineering - the ratio of open area to total area of a screen or other porous barrier structure
positive barrier hydraulic engineering - a structure that excludes fish through physical or hydraulic means
posterior biology/anatomy - on the rear or back side
potamon zone biology - a stream reach with very slow flow, elevated temperatures and low dissolved oxygen
ppb chemistry - parts per billion, equivalent to µg/kg and usually applied to solid samples and liquid samples with high salinity or density (see unit conversion factors)
ppm chemistry - parts per million, equivalent to mg/kg and usually applied to solid samples and liquid samples with high salinity or density (see unit conversion factors)
ppt chemistry - parts per trillion, equivalent to ng/kg and usually applied to solid samples and liquid samples with high salinity or density; may also be parts per thousand, a unit for salinity (see unit conversion factors)
PQL chemistry - practical quantitation limit
precision statistics/quality assurance - the repeatability or variability of measurements, usually expressed as a standard deviation or other error
predator biology - an animal that eats other animals
preopercle biology/anatomy - small bone on fin ray fishes immediately anterior to opercular bone
primary hydraulic engineering - the first fish diversion channel at the Tracy Fish Collection Facility, located behind the trash rack and containing the primary louver structure and fish bypasses. See schematic diagram.
primary productivity biology - total biomass per unit time produced by organisms in a given habitat, such as plankton in water
probit analysis statistics/toxicology - a logistic regression used to analyze bioassay data and calculate LC50, LD50, or other indicators of toxicity
profile any collection of a measurements made over several cross-sectional units (depth, altitude, elevation, etc.); limnology - a plot of water quality variables such as T, DO, or pH with depth, measured at a specific time and location in a water body
protein biochemistry - important class of large biological molecules that usually contain a long and complexly folded structural unit (made from fatty acids or polysaccharides) with attached peptide side chains formed from amino acids
protozoa biology - single celled animals
q hydraulic engineering/hydrology - water flow, measured in volume per unit time, such as m3/s or ft3/s (cfs)
QA quality assurance, efforts and tests performed external to the lab to make sure that a lab is following the QC requirements. These could include lab and field sampling audits, or submission of known concentration samples as blind check samples
QC quality control, efforts and tests undertaken in the lab to check or document analysis data quality
r, R2 statistics - r is the correlation coefficient, a measure of interdependence between two variables; R2 is called the coefficient of determination, a measure of the percent variance explained by a model; adjusted R2 has been corrected for degrees of freedom
rad physics - radiation absorbed dose, a non-SI unit for exposure to radiation, equal to 0.01 J/kg, or 0.01 Gy (gray, the SI unit) (see unit conversion factors)
RCRA Resource Conservation and Recovery Act, Public Law 94-580, 40 CFR 240-271, 1976; federal law regulating hazardous waste disposal
recovery chemistry - observed concentration divided by theoretical or true concentration, usually expressed as a percentage
redd biology - prepared habitat where fish eggs are deposited
reducing chemistry - a chemical environment where oxygen is absent and/or excess electrons are available; in natural waters, an anaerobic environment where compounds may undergo reduction from a higher oxidation state to a lower oxidation state, such as nitrate, NO3- (N in the +V oxidation state), being reduced to nitrite, NO2- (N in the +III oxidation state), or sulfate SO42- (S in the +VI oxidation state), being reduced to sulfide S2- (S in the +II oxidation state); a natural water environment with negative Eh
redox chemistry - REDuction-OXidation; referring to oxidation-reduction conditions
regression statistics - a statistical analysis that compares one or more independent variables, xi, to predict a dependent variable, y
residual statistics - the difference between each observation and the average, either the mean or the predicted y-value from a regression
residual sum of squares, RSS statistics - the sum of squared residuals for a population, sample, or regression; used to calculate other statistics, such as variance and standard deviation
respiration biology - the process by which an organism obtains oxygen needed to process food into energy
ρ Greek letter rho; chemistry/physics - density, measured in g/cm3 at STP
RMP Regional Monitoring Program - the water quality data coordination and archiving effort performed by the San Francisco Estuary Institute (SFEI)
roe biology - fish eggs while inside the female
RPD chemistry - Relative Percent Difference, a way to calculate precision from duplicate data
RPP Red Bluff Research Pumping Plant, Bureau of Reclamation
s statistics - sample standard deviation
s2 statistics - s squared, the sample variance
salmonid biology - fish classified in family Salmonidae, that includes trouts, salmons, chars, and whitefishes
Saturation Index chemistry - a unitless number pertaining to the chemical reaction of a mineral compound with water, calculated as log(AP/KT), where AP is the activity product, K is the equilibrium constant, and T is the Kelvin temperature. The saturation index, calculated by several computer chemical equilibrium models such as MINTEQ and PHREEQE, indicates whether a given natural water is oversaturated (positive numbers), undersaturated (negative numbers), or near equilibrium (values near zero) with a particular mineral phase.
Sb chemistry - the element antimony
scale biology - a platelike overlapping structure that forms the epidermis of a fish or reptile
screen hydraulic engineering - a porous structure with a given mesh size or porosity
SDWA Safe Drinking Water Act; Public Law PL 93-523, 42 U.S.C. 300f, 1974; federal environmental law regulating toxic chemicals in drinking water; SDWA defines the National Primary Drinking Water Stanards (40 CFR 141) and the National Secondary Drinking Water Standards (40 CFR 143)
Se chemistry - the element selenium
secondary hydraulic engineering - term applied to the second fish diversion channel at the Tracy Fish Collection Facility, located behind the primary louvers and fed by flow from the primary fish bypasses. The secondary also contains a louver structure with a single fish bypass that conveys fish into the holding tanks for subsequent salvage and transport back to the San Joaquin River. See schematic diagram.
SEE statistics - standard error of the estimate
sessile botany - stalkless leaves attached at the base; zoology - permanently attached or fixed
seston biology - free floating plankton and suspended pariculate matter in water
SFEI San Francisco Estuary Institute
SI Système Internationale d'Unités, the international standard system for metric measurement units
σ Greek letter sigma; statistics - standard deviation of the population
σ2 statistics - sigma squared, the variance of the population
SJR San Joaquin River
SLDMWA San Luis Delta Mendota Water Authority
smolt biology - young fish in transition between juvenile and adult lifestages
Sn chemistry - the element tin
snout length biology/anatomy - length from eye to tip of snout
SO42- chemistry - sulfate, or sulfate ion, the dominant form for sulfur in oxygenated natural waters
solute chemistry - the chemical that is dissolved into the solvent
solvent chemistry - the chemical that dissolves the solute
spawning biology - fish reproductive activity
standard length, SL biology - length of a fish from tip of snout to beginning of caudal fin
stochastic statistics - a model or process involving random variables or probability
stoichiometry chemistry - the process of algebraically balancing chemical reactions; referring to the balanced equation and product and reactant coefficients for a given chemical reaction
STP chemistry - standard temperature and pressure, equal to 1 atm and 273 °K (0 °C)
su or s.u. chemistry - standard units, usually applied to pH
S2- chemistry - sulfide ion, a reduced form of sulfur in the +II oxidation state, found only in anaerobic and reducing natural waters
suspended chemistry - an operationally defined term applied to water analysis results; analytes associated with suspended particles larger than 0.45 µm, usually calculated by subtracting dissolved from total
sustained speed biology - the maximum speed an organism can maintain for periods of time on the order of minutes
sweeping velocity hydraulic engineering - the water velocity in ft/s or m/s measured parallel to a louver or positive barrier screen
SWP State Water Project
T temperature
t, t-test statistics - Student's t-test, a statistical test used to test equality of means from two variables having normal distributions and equal variances; a critical value from the t-distribution
take regulatory - animals or plants protected by the Endangered Species Act (ESA) that are killed, harmed, collected, caught, or trapped; defined in Section 9 of the ESA
taxis biology - movement associated with an organism
TDFF Tracy Demonstration Fish Facility, a research facility proposed to be located across the channel from the Tracy Fish Collection Facility
TDS chemistry - total dissolved solids, mg/L, also called "Filterable Residue"
TEFF Tracy Experimental Fish Facility, former name for TDFF, Tracy Demonstration Fish Facility
teratogenic biology/toxicology - referring to a chemical compound or environmental influence that causes developmental defects
TFCF Tracy Fish Collection Facility
TFFIP Tracy Fish Facility Improvement Program
TFRED Tracy Facility Research and Evaluation Document Team
TFTF Tracy Fish Test Facility, former name for TDFF - Tracy Demonstration Fish Facility
threatened species regulatory - a class of protected species under the Endangered Species Act (ESA); species that are not in imminent danger of extinction, but show population trends suggesting concern
Ti chemistry - the element titanium
titrimetric chemistry - an analytical method that uses a titration
TKN chemistry - total Kjeldahl nitrogen, an digestion analysis that detects both ammonia and organic nitrogen
Tl chemistry - the element thallium
TM chemistry - trace metals
TMDL Total Maximum Daily Load; a flow-weighted average for regulating pollution discharges in watershed reaches under the Clean Water Act
TOC chemistry - total organic carbon
total chemistry - an operationally defined term applied to water analysis results, usually meaning an unfiltered sample that is digested or extracted prior to analysis
total length, TL biology - the length of a fish from the tip of the snout to the terminus of the caudal fin
t-P, total-P chemistry - total phosphorus
TPP Tracy Pumping Plant, U.S. Bureau of Reclamation, Byron, California
trace elements chemistry - a general term applied to low concentration (less than a mg/L) transition metals such as Fe, Pb, Hg, Cd, Cu, Zn, and other elements such as As, Se, and Mo; sometimes called trace metals or toxic metals
trivalent chromium chemistry - one of the common forms of chromium in natural waters; chromium in the +III oxidation state, as in Cr3+
TSC Technical Service Center, Bureau of Reclamation, Denver, Colorado
TSCA Toxic Substances Conrtol Act, Public Law PL 94-469, 40 CFR 700-799, 1977; federal environmental law regulating chemicals not covered under other regulations; covers testing procedures for chemical fate, and environmental and health effects.
TSS chemistry - total suspended solids, mg/L, also called "nonfilterable residue"
TTAT Tracy Technical Advisory Team
turbidity chemistry - particulate matter in water that scatters light causing a cloudy appearance
turbulent flow hydraulic engineering - flow that is fast, complex, and chaotic
U chemistry - the element uranium; quality assurance - EPA data validation code forundetected
ultra-trace chemistry - referring to chemical compounds in water at very low concentrations, usually less than 10 µg/L
USBR, BOR U.S. Department of the Interior - Bureau of Reclamation
USGS U.S. Department of the Interior - Geological Survey
V electricity - volt, SI voltage unit; chemistry - the element vanadium
valence chemistry - the oxidation state of an element, usually denoted by Roman numerals, as Fe(+III) or S(+VI); valence is used to calculate equivalent weight
vascular plant biology - a multicellular plant containing vessels for transport of nutrients
velocity profile hydraulic engineering - the description of water velocity at several depths, usually shown as a graph of water velocity vs. depth
ventral, ventral fin biology/anatomy - located on the bottom; a bottom fin on a fish
vertebrate biology - an animal having a backbone
WEF Water Environment Federation
wetland biology - an area that collects water during part or all of the year
Wilcoxon-Mann-Whitney test statistics - a nonparametric (distribution independent) test for equality of central tendency estimates of two populations based on ranking of the combined sample; also called Mann-Whitney test
z, z-scale statistics - standardized data that have been scaled to have mean = 0 and standard deviation = 1
Zn chemistry - the element zinc
zooplankton biology - free floating microscopic aquatic animals

J. Carl Dealy, TFFIP Manager
(209) 836-6236

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Last Updated: 11/9/20