A
Aquifer
A layer of gravel, sand, or porous, fractured, or cavernous rock capable of holding and/or conducting water. An aquifer saturated with water is referred to as being fully charged. An aquifer is a formation, group of formations or part of a formation containing enough saturated permeable material to produce significant amounts of water to wells and springs. A confined or artesian aquifer is an aquifer bounded both below and above by beds of considerably lower permeability than that in the aquifer itself. The groundwater in a confined aquifer is under pressure that is significantly greater than that existing in the atmosphere.

Artesian Well
A well obtaining its water from an artesian or confined aquifer in which the water is forced upward from below. The water level in a flowing artesian well rises above the land surface.

B
Blackwater
Wastewater from toilets.

Biodiversity
The variety, distribution and abundance of different plants, animals, and microorganisms; the ecological functions and processes they perform; and the genetic diversity they contain.

D
Drought
In British Columbia there is no easy definition of this condition. Three different types of drought may be considered when deciding whether or not a given area is suffering drought conditions. These are: 1) meteorological drought – a lack of precipitation, 2) agricultural drought – lack of soil moisture to support crops, 3) hydrological droughts – low water levels in streams, lakes and wells.

E
Evapotranspiration
The movement of water from the soil, an individual plant, or plant communities to the atmosphere by evaporation of water from the soil and transpiration of water by plants.

G
Greywater
Wastewater generated by household processes such as washing dishes, laundry and bathing.

Groundwater
The water that moves down into the soil from the upper soil layers following precipitation. Groundwater is stored in aquifers. Groundwater may move underground by streams and seepage.

H
Hydrologic or Hydrological Cycle
The continuous circulation of water between the ocean, atmosphere and land.

I
Infiltration
The movement of water from the surface into the soil.

M
Mainstem
The main course of a river or stream where most of the water flows most of the time.

Maximum Contaminant Level (MCL)
The greatest amount of a contaminant that can be present in water without causing a risk to its intended use; the maximum level of a contaminant allowed in water to maintain aquatic life, to minimize pollution, to permit recreation, or to allow water to be used as a drinking water source.

P
Percolation
The movement of water down through the subsurface layers of soil, usually continuing to the depth of groundwater or water table. The oozing or soaking of water through openings in rock or soil. The entrance of a portion of the stream flow (surface water) into the channel materials (silt, rock, soil) and making its way down through the soils to become part of groundwater.

R
Recharge Rate
The volume of water coming from precipitation (rain and snow) that flows into an aquifer over a unit time period.

Riparian
Pertaining to anything connected with or immediately adjacent to the banks of a stream or other body of water.

Riprap
A layer of large rocks placed along stream banks or lakeshores to protect them from erosion. It also refers to the rocks themselves.

Runoff
The part of precipitation and snowmelt that reaches streams by flowing over or through the ground. Surface runoff flows away without penetrating the soils.

S
Storm Water
Water which is primarily surface runoff from streets and other impervious surfaces associated with urbanization/development.

Surface Water
Water that flows in streams and rivers, lakes and ponds, in wetlands and in reservoirs constructed by humans, but on the surface of the land and not underground as distinguished from groundwater.

T
Tributary
A smaller stream which flows into a larger stream. Usually a number of tributaries flow into a larger water course to form a river.

W
Wastewater
Water with waste materials or pollutants in it, including greywater, blackwater or other contaminated water. Wastewater is not suitable for reuse unless treated.

Watershed
The land on which precipitation falls from the atmosphere and moves downslope to other locations. Each watershed is a catchment area divided from the next watershed by topographic features, most noticeably ridgetops.

Water Cycle
See Hydrologic Cycle

Water Quality
The chemical, physical and biological characteristics of water.

Water Table
Below a certain depth, the ground is saturated with groundwater. This is the saturated zone. Above this depth, the pores and fracture spaces are unsaturated and may contain some water and air. This is the unsaturated or vadose zone. At the top of the saturated zone, as well as in the vadose zone, the groundwater is held in the pores and fracture spaces under tension (negative or vacuum pressure) by capillary forces. This thin saturated layer where water is held under tension is the capillary fringe. The pressure head increases from a negative value at the top of the capillary fringe to zero at the bottom of the capillary fringe. The bottom of the capillary fringe layer where pressure head is zero is defined as the water table.