WATER GLOSSARY

Acre-foot: The amount of water required to cover one acre to a depth of one foot. It is equal to 325,851 gallons.

Active Management Area (AMA): A geographical area that has been designated by the Legislature as requiring active management of ground water withdrawals from pumping.

Alluvium: Sediments of varying sizes deposited by flowing water as in a river bed or flood plain.

Aquifer: A geologic formation, group of formations, or part of a formation that contains sufficient saturated material capable of transmitting significant quantities of water to wells and springs.

Baseflow: Groundwater that has been discharged into a stream channel as spring or seepage water.

CFS: A unit of measure of unit of flowing water. One CFS means that one cubic foot of water or 7.48 gallons, passes a given point during an interval of one second (449 or minute).

Direct Runoff: Water entering stream channels promptly after rainfall or snowmelt.

Discharge: The volume of water flowing in a stream or through an aquifer past a specific point in a given period of time.

Discharge of groundwater: The process by which water leaves an aquifer.

Diversion: A structure or facility, such as a damn, built for the purpose of taking water from a source.

Effluent: Treated waste water which may be used for various purposes.

Ephemeral Stream: A stream that flows only in direct response to precipitation.

Flood Plain: Lowland area adjacent to the active stream channel that is periodically inundated by flood water; the land outside of a stream channel formed by sediments deposited by the stream.

Gauging Station: A location along the watercourse where stream flow is regularly measured by permanently installed equipment.

Groundwater: The water contained in interconnected pores located bellow the water table in an unconfined aquifer or located in a confined aquifer.

Groundwater Water Recharge: The natural or artificial replacement or groundwater, or addition of water to a groundwater aquifer.

Hydrogeology: The study of the interrelationships of geologic materials and processes with water, especially groundwater.

Infiltration: The flow of water downward from the land surface into and through the upper soil layers.

Intermittent Stream: A stream that flows only at certain time of the year or flows seasonally. Streamflow is supported by baseflow during part of the year when the elevation of the water table in an adjacent aquifer rises above the streambed elevation.

Instream Flow: The amount of water remaining in a stream, without diversion, that is required to maintain a particular aquatic environment or water use.

Monitoring Well: A well drilled with the specific purpose of measuring groundwater elevation or quality.

Perennial Stream: A stream that flows continuously year round.

Precipitation: Any form of rain, snow or hail falling to the earth's surface.

Reach: A specific length of a river, stream or channel.

Recharge: The addition of water to an aquifer by natural infiltrat5ion or by artificial injection through wells.

Riparian Area: A geographically declined area with a distinct resource value. It is characterized by deep-rooted plant species that depend on having roots in the water table or its capillary zone and that occurs within or adjacent to a natural perennial or intermittent stream channel or within or adjacent to a lake, pond, or marsh bed maintained primarily by natural water sources.

Runoff: The total amount or water flowing in a stream. It includes overland flow, return flow, interflow, and Baseflow.

Safe Yield: The amount of naturally occurring groundwater that can be economically and legally withdrawn from an aquifer on a sustained basis without impairing the native groundwater quality or creating an undesirable effect such as environmental damage. It cannot exceed the increase in recharge or leakage from adjacent strata plus the reduction in discharge, which is due to the decline in head caused by pumping.

Storage: The volume of water naturally detained in an aquifer.

Sub-basin: An area which encloses a relatively hydrological distinct body of groundwater within a groundwater basin, and which is described horizontally by surface description.

Subflow: Subsurface water in alluvial deposits that are hydraulically connected to a perennial or intermittent stream such that withdrawal of this subsurface water would diminish the flow of the stream. It is the downstream flow of water through the permeable deposits that underlie a stream and are vertically and laterally bounded by rocks or sediments of lower hydraulic conductivity.

Sustainability: A decision making concept describing development that meets current needs without compromising the ability of future generations to meet their needs.

Surface Water: Water that occurs on the land surface including ponds, lakes, streams and rivers.

Water Budget: An evaluation of all the sources of supply and the corresponding discharges with respect to an aquifer or a drainage basin.

Watershed or Drainage Area: An area in which water drains to a single point; in a natural basin, the area contributing flow to a given place or a given point on a stream.

Water Table: The top zone of saturation in the ground.

Wetland: Area with standing water or a high water table either permanently or for some significant period each year generally includes swamps, marshes, bogs and areas with water-loving vegetation that grows in or around water.

Xeriscape: A landscape concept to describe beautiful landscaping that has low water needs.