aquifer: A formation, group of formations, or part of a formation that contains enough saturated permeable material to yield sufficient, economical quantities of water to wells and springs.
bedrock: a general term for the consolidated rock that underlies soils or other unconsolidated surficial materials.
community public water supply system: water systems that serve a permanent residential population and include municipalities, rural water systems, mobile home courts, and housing developments.
conduit flow: groundwater movement down-gradient along fractures, faults, joints, bedding planes, and solution openings resulting in 'flashiness'. Flashiness is indicated by rapid aquifer recharge; turbulent flow; and highly variable chemistry, temperature, and flow rates. Darcy's Law does not apply in conduit flow conditions.
confined aquifer: An aquifer bounded above and below by confining units of distinctly lower permeability than the aquifer media; or an aquifer containing confined groundwater. An aquifer in which groundwater is under pressure significantly greater than atmospheric and its upper limit is the bottom of a bed of distinctly lower hydraulic conductivity than that of the aquifer itself.
consecutive public water supply system: a water system that is served by another public water supply system.
contaminant: An undesirable substance not normally present, or an unusually high concentration of a naturally occurring substance in water, soil, or other environmental medium.
contamination: The degradation of natural water quality as a result of man's activities. There is no implication of any specific limits, since the degree of permissible contamination depends on the intended end use or uses of the water.
contaminant source inventory: the process of identifying and inventorying potential sources of contamination delineated source water assessment areas through recording existing data, describing contaminant sources within the source water assessment area, targeting likely contaminant sources for further investigation, and verifying accuracy and reliability of the information gathered.
diffuse flow: groundwater movement down-gradient along fractures, faults, joints, and bedding planes resulting in less turbulent flow, slower aquifer recharge, and more uniform chemistry, temperature, and flow rates than observed in conduit flow. Groundwater movement is similar to that in porous flow environments and may be described using Darcy's Law. Groundwater movement through a fractured-rock aquifer may be considered to be diffuse flow if: 1) the fractures are closely spaced, 2) the fractures are evenly sized, evenly distributed, and randomly oriented, and 3) the area of consideration is large relative to the spacing of the fractures. Criteria such as pumping test responses, configuration of the water table, water chemistry variations, distribution of hydraulic conductivity, and the ratio of the fracture scale to the problem scale may be used to determine which type of flow regime exists.
drawdown: the vertical distance ground water elevation is lowered, or the amount pressure head is reduced, due to the removal of ground water. Also the decline in potentiometric surface caused by the withdrawal of water from a hydrogeologic unit.
Drinking Water State Revolving Fund (DWSRF): under section 1452 of the Safe Drinking Water Act, the EPA awards capitalization grants to states to develop drinking water revolving loan funds to help finance drinking water system infrastructure improvements, Source Water Protection, to enhance operations and management of drinking water systems, and other activities to encourage Public Water System compliance and protection of public health.
groundwater: The water contained in interconnected pores located below the water table in an unconfined aquifer or located in a confined aquifer.
hydraulic conductivity (k): Proportionality constant relating hydraulic gradient to specific discharge, which for an isotropic medium and homogeneous fluid, equals the volume of water at the existing kinematic viscosity that will move in unit time under a unit hydraulic gradient through a unit area measured at right angles to the direction of flow.
hydraulic gradient (I): slope of the water table or potentiometric surface.
igneous rock: A rock that solidified from molten or partly molten material.
karst: a landscape or region characterized by rock dissolution.
metamorphic rock: a rock formed when preexisting rocks undergo mineralogical, chemical, and structural changes caused by high temperature, pressure, and other factors.
non-transient non-community public water supply system: nonresidential water systems that serve the same population for at least six months per year and includes factories and schools.
permeability: ability of a porous medium to transmit fluids under hydraulic gradient.
porosity: ratio of the total volume of voids available for fluid transmission to the total volume of a porous medium. Also the ratio of the volume of the voids of a soil or rock mass that can be drained by gravity to the total volume of the mass.
potentiometric surface: an imaginary surface representing the level to which water will rise in a well.
public water supply system (PWS): system for provision to the public of piped water for human consumption, if such system has at least 15 service connections or regularly serves at least 25 individuals daily or at least 60 days out of the year.
pumping rate: the rate at which water is withdrawn from the well.
radius of influence: the radial distance from the center of a well bore to the point where there is no lowering of the water table or potentiometric surface.
recharge area: area in which water reaches the zone of saturation by surface infiltration. An area in which there are downward components of hydraulic head in the aquifer. Infiltration moves downward into the deeper parts of an aquifer in a recharge area.
semiconfined aquifer: an aquifer that has a "leaky" confining unit and displays characteristics of both confined and unconfined aquifers.
sensitivity: the potential for a water source to become contaminated based on the intrinsic hydrogeologic characteristics of the watershed or aquifer.
source water assessment area: the area delineated by the state for a public water supply, whether the water source is groundwater or surface water or both, as part of the state Source Water Assessment and Protection program approved by EPA under section 1452 of the Safe Drinking Water Act.
source water assessment: three step process which includes delineating the part of the watershed or groundwater area that contributes water to the water supply system; identifying the potential sources of pollution in the delineated area; and conducting a susceptibility analysis of the water supply to potential contaminant sources.
susceptibility: the potential for a public water supply system to draw water contaminated at concentrations that would pose concern, through geologic strata and overlying soil, direct discharge, overland flow, or cracks/fissures in the physical well or surface-water intake.
transient, noncommunity public water supply system: water systems that serve a transient or nonresidential population and includes campgrounds, rest stops, and resorts.
time of travel: the time required for a contaminant to move in the saturated zone from a specific point to a well.
unconfined aquifer: conditions in which the upper surface of the zone of saturation forms a water table under atmospheric pressure.
watershed area: a topographic area that is within a line drawn connecting the highest points uphill of a drinking water intake, from which overland flow drains to the intake.
wellhead protection area: a designated area around a public water supply well(s) that is to be protected from contaminants that may adversely affect human health.
Wellhead Protection Program: A program to protect wellhead protection areas within a states jurisdiction from contaminants that may have any adverse effects on the heath of persons (Safe Drinking Water Act, subsection 1428(a)).
Chapters
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Glossary |
Acronyms
Appendices
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D
Wyoming's Source
Water Assessment Guidance Document Contents