riverbed

The San Gabriel River Discovery Center guides visitors through the world of the San Gabriel River watershed, its history, plants and animals and how we use and manage water in the Los Angeles area.  The glossary introduces us to the words we need to learn about to discuss nature, water and how to protect the environment.

A
acre-feet
How water is measured, equal to about 326,000 gallons 

allotment
A share or portion. 

aqueduct
A structure used to transport water from remote areas to large urban centers. 

aquifer
An underground space where water collects. 

artesian aquifer
A confined aquifer where water is contained under great pressure between two impermeable layers.

B
bacteria
A single-celled microscopic organism. 

bog
A wetland covered by a shallow layer of water, or no visible water at all, and containing ground that is made of sphagnum moss. 

bottom life
Animals that live on the bottom of a healthy body of water.

brackish water
Refers to water with a mineral content in the general range between freshwater and seawater.

C
California Aqueduct
a 444-mile structure that transports water from the San Francisco/San Joaquin Delta to Southern California. 

Central Basin Aquifer
an aquifer that underlies the Southern California communities of Central Basin Municipal Water District within its territory. 

Clean Water Act of 1972
A law that requires the federal government to regulate the quality of the nation’s water supply. 

Colorado River Aqueduct
A 242-mile structure that transports water from the Colorado River to Southern California. 

Comprehensive Environmental Response, Compensation and Liability Act of 1980 (Superfund)
A law enacted by the federal government to clean up hazardous waste sites that threaten groundwater resources. 

condensation
Water vapor or gas forming a cloud prior to becoming a liquid again. 

confined aquifer
An aquifer found between two impermeable layers. 

conservation
saving water and other natural resources.

D
dam
A structure used to hold back the flow of water.

desalination
A process that removes dissolved salts from salty or brackish water. 

dike
A structure used to confine or control water. 

disinfection
A process in which chlorine and other chemicals are added to water to kill harmful microorganisms. 

diversion canal
A structure used to change the directional flow of water. 

desalination
Salt removal from sea or brackish water.

E
estuary
An area where a river empties into an ocean or sea. 

evaporation
Water turned into a vapor or gas and rising into the atmosphere.

F
filtration
A process that separates small particles from water by using a porous barrier to trap the particles and allowing the water through.

fish
A vertebrate (animal with a spine) that lives in water.

flocculation
A process in which a chemical such as alum or ferric chloride is added to water to cause dirt and other small particles to join together into “floc” or large clumps.

G
groundwater
Water that is stored in aquifers. Aquifers are replenished naturally with rainfall or snowpack or artificially through recharge basins with imported or recycled water.

H
hydrologic cycle
A three-step process by which Earth is continuously able to recycle its water.

I
imported water
Water transported to our region from Northern California or the Colorado River Aqueduct.

L
levee
A raised structure used to contain water and prevent flooding. 

Los Angeles Aqueduct
A 335-mile structure that transports water from the eastern Sierra Nevada to the City of Los Angeles.

M
mangrove swamp
Tropical and subtropical saltwater swamp that contains a species of saltwater tolerant tree or shrub. 

marsh
A wetland that is wet throughout the year and found at the edge of a river, lake or pond.

N
non-potable water

Water not suitable for drinking. Can be used for landscaping, irrigation and industrial uses. 

non-point pollution source
Pollution that comes from various sources not easily identified.

O
Ogalla Aquifer
The largest aquifer in the United States, located in the Midwest. 

organism
A living plant or animal. 

oxygen
A gas upon which most life depends.

P
potable water
Water that is suitable for drinking. 

peak flow
Highest flow level of a body of water. 

permeability
A measurement of how freely water moves between pieces of soil and rock. 

phytoplankton
Microscopic free-floating green plants. 

point pollution source
Pollution that comes from an easily identified source. 

porosity
A measurement of the amount of water held between pieces of soil and rock. 

Porter-Cologne Water Quality Act
A California law that gives the State Water Resources Control Board ultimate authority over water rights and water control policy.

precipitation
Water falling to Earth as rain, sleet, snow or hail. 

pretreatment
A process in wastewater treatment where metal screens are used to remove large objects and chunks of debris. 

primary treatment
The first process in wastewater treatment where solid matter is removed.

R
reclaimed or recycled water
Cleaned wastewater that can be reused for non-drinking purposes. 

recycled water
Domestic wastewater purified through primary, secondary and tertiary treatment. Recycled water is ideal for most non-drinking water purposes such as landscaping, irrigation and industrial uses.

S
Safe Drinking Water Act of 1974
A law enacted by the federal government that regulates the nation’s drinking water. 

saltwater marsh
A wetland that is wet throughout the year and found at the edge of a saltwater body. 

secondary treatment
The second process in wastewater treatment where microorganisms are used to digest organic particles. 

sediment
Mud, sand or gravel that has settled to the bottom of a body of water. 

sedimentation
A process in which gravity causes small particles to settle to the bottom of a tank or basin. 

semi-arid
A mostly dry region that gets a small amount of precipitation. 

Superfund
See Comprehensive Environmental Response, Compensation and Liability Act. 

surface water
A body of water easily seen as it flows downhill to where it collects. 

swamp
A wetland that can alternate between being wet and dry for periods of time throughout the year.

T
tertiary treatment
The third process in wastewater treatment where remaining small particles are filtered out of the water before disinfection. 

turbidity
Cloudy or muddy looking water caused by suspended or stirred up particles in the water.

U
Ultra-Low-Flush Toilet
Often referred to as ULFTs, these fixtures require only 1.6 gallons of water per flush. These conservation devices save a typical household 7,900 to 21,700 gallons of water each year. 

unconfined aquifer
An aquifer found close to Earth’s surface that allows water to seep into it.

W
water conservation
The best tool for stretching water supplies without making unnecessary investments in infrastructure, shifting available water resources or negatively impacting the environment.  

watershed
An area of land where water drains from the higher elevation points into a larger body of water or into the soil. 

water table
The top surface of a body of groundwater. 

well
A hole dug into the ground that begins at the surface and ends where it reaches the water. 

West Coast Basin Aquifer
An aquifer that underlies the Southern California communities of West Basin Municipal Water District within its territories. 

wetland
An area of land that is wet for a period of time during the year.

Z
zooplankton
Microscopic free-floating animals.