See also
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Aquifer - A geological formation that contains sufficient saturated permeable material to yield
significant quantities of water to wells and springs.
Aquifer Stress Assessment - Water use is sustainable when supply and demand are in balance. When more water is extracted than replenished, an aquifer may experience stress. Aquifer stress compares the total demand for groundwater to the amount of natural aquifer recharge.
Aquitard - A geological formation, or part of a formation, through which virtually no water moves.
Bedrock - The solid rock that underlies unconsolidated surficial sediments.
Bedrock aquifer - A bedrock unit that has the ability to transmit significant volumes of water to a well completed within it. Typical examples include sandstone and siltstone or significantly fractured intervals.
Block-Faulted - High-angle faulting in which blocks of the crust move vertically up or down relative to each other. Often occurs in areas undergoing horizontal extension.
Brackish water - Slightly salty. In this study, defined as water with a chloride concentration of greater
than 250 mg/L (EC greater than 1,000 μS/cm) and less that of seawater (~19,000 mg/L).
Cadastre - Property boundary.
Channel - An eroded depression in the soil or bedrock surface within which alluvial deposits accumulate (i.e. gravel, sands, silt, clay).
Contaminant - A substance that is present in an environmental medium in excess of natural baseline concentration.
Contemporaneous - Formed or existing at the same time.
Cumulative Effects - The changes to the environment caused by all past, present, and reasonably foreseeable future human activities.
Datalogger - Submersible electronic device that records characteristic data collected from
groundwater such as level, temperature, electrical conductivity, etc.
Demand - Water demand is an estimate of actual water use.
Drawdown - The distance between the non-pumping water level and the surface of the cone of depression.
DWWP - Drinking Water & Watershed Protection program - Through the RDN's DWWP, we are working to learn more about water in the Region, use this information to make better land use decisions, and help communities protect the environment. The DWWP is supported by the City of Nanaimo, District of Lantzville, City of Parksville, Town of Qualicum Beach, and the RDN’s seven electoral areas. Learn more at dwwp.ca
Evaporation - The process by which water changes from a liquid to atmospheric water vapour – an essential part of the water cycle.
Evapotranspiration - The process by which water is discharged to the atmosphere as a result of evaporation from the soil and surface-water bodies and transpiration by plants. Transpiration is the process by which water passes through living organisms, primarily plants, into the atmosphere.
Fault - A break in material in which material on one side of the break has moved relative to that on the other side. In the Foothills and Rocky Mountain Front Ranges Thrust faulting is the most common – Thrust faults are low angle faults in which older material may be ‘thrust over’ younger material.
Fluvial - Produced by the action of a stream or river
Fresh water - As defined in this study, water with chloride concentration below the CDWQG value of
250 mg/L (EC of less than ~1,000 μS/cm).
Freshwater lens - In this study, the static body of groundwater (does not include transient recharge
mounding) that floats above the denser, saline water below.
Geological formation - A geological unit or group of units with similar age or type of depositional
history, and other geological similarities on larger regional scale.
Geological unit - A volume of rock with similar lighology or other geologic properties.
Geometric mean - A geometric mean, unlike an arithmetic mean, tends to dampen the effect of very high or low values, which might bias the mean if a straight average (arithmetic mean) were calculated. This is helpful when analyzing transmissivity estimates, which may vary over 10 orders of magnitude. A geometric mean is a log (base 10) transformation of data to enable meaningful statistical evaluations.
Groundwater - All water beneath the surface of the ground whether in liquid or solid state.
Hydraulic conductivity - The rate of flow of a unit volume of water a prevailing density and viscosity passes through one square unit of porous medium under a unit hydraulic gradient (meters/second).
Hydraulic Gradient - In an aquifer, the rate of change of total head per unit distance of flow at a given location and direction. It has both horizontal and vertical components.
Hydrogeological unit - A volume of rock or sediment which has similar hydraulic properties for groundwater flow.
Hydrogeology - The science that relates geology, fluid movement (i.e. water) and geochemistry to understand water residing under the earth’s surface. Groundwater as used here includes all water in the zone of saturation beneath the earth’s surface, except water chemically combined in minerals.
Infiltration - The flow or movement of precipitation or surface water through the ground surface into the subsurface. Infiltration is the main factor in recharge of groundwater reserves.
Instream Flow Needs - The amount of water required in a river to sustain a healthy aquatic ecosystem, and/or meet human needs such as recreation, navigation, waste assimilation or aesthetics.
Karst - An area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns.
Lacustrine - Fine-grained sedimentary deposits associated with a lake environment and not including shore-line deposits
Litholog - For this study; a record (log) of the rock types encountered during drilling. The Ministry of
Environment well database contains summary lithologic units made by drillers.
Monitoring Well - A constructed controlled point of access to an aquifer which allows groundwater observations. Small diameter observation wells are often called piezometers.
Numerical modelling - A method of describing groundwater flow by mathematical approximations with
specified values for boundary conditions.
Overburden - Any loose material which overlies bedrock (often used as a synonym for Quaternary sediments and/or surficial deposits) or any barren material, consolidated or loose, that overlies an ore body.
Permeability - A physical property of the porous medium providing an indication of how easily water will flow through the material. Has dimensions Length2. When measured in cm2, the value of permeability is very small, therefore more practical units are commonly used - Darcy (D) or millidarcy (mD). One darcy is equivalent to 9.86923×10−9 cm².
Precipitation - Rainfall and snowfall, expressed as depth of water equivalent which accumulates on
land or water, measured with rain gauges. Not all precipitation infiltrates to the aquifer.
Receptor - Components within an ecosystem that react to, or are influenced by, stressors.
Recharge - Water from precipitation and surface waters which infiltrates down to the water table and
adds to water storage in the aquifer.
Reservoir - An artificial lake used to store water.
Salt water - As defined in this study, water with chloride concentration above the CDWQG value of
250 mg/L (EC of greater than ~1,000 μS/cm).
Saltwater Intrusion - The migration, either lateral or vertical, of saltwater into freshwater aquifers under the influence of groundwater development such as pumping of freshwater near a source of saltwater.
Significant Aquifer - A permeable water-bearing horizon of sufficient thickness and lateral extent that can yield useable quantities of water. An aquifer in excess of 5 m thick, 100 m or more in width and extending a lateral distance of 500 m or more may be considered a significant aquifer.
Static - Characterized by a fixed or stationary condition.
Steady-state - A condition that does not change over time, or in which any one change is continually
balanced by another, such as the stable condition of a system in equilibrium.
Storativity - The volume of water released from, or taken into, storage by a confined aquifer per unit surface area of aquifer per unit change in hydraulic head.
Stratigraphy - The geological science concerned with the study of sedimentary rocks in terms of time and space.
Stress - Stress is a relative measure that compares the amount of water going into and out of a system. When more water is extracted than replenished, the system may experience stress. Stress can also be seasonal and variable.
Aquifer stress compares the total demand for groundwater to the amount of natural aquifer recharge. Surface water stress compares the total demand and minimum conservation flows to the amount of natural water supply and storage.
Strike - The strike line of a bed, fault, or other planar feature is a line representing the intersection of that feature with a horizontal plane.
Subcrop - An occurrence of the strata directly beneath an unconformity (e.g., base of unconsolidated materials constituting a weathering surface).
Surface Water - Water that flows in streams and rivers, and exists in natural lakes, wetlands, and in reservoirs.
Sustainable - A characteristic of an ecosystem that allows it to maintain its structure, functions and integrity over time and/or recover from disasters without human intervention.
Thalweg - The line defining the lowest points along the length of a river bed or valley. Also the line defining the central (long) axis of a buried channel or valley.
Thrust Faulting - A shallow dipping fault in which the hanging wall moves up relative to the footwall. It is caused by horizontal compression. This results in placing older rock over younger rock.
Till - A sediment deposited directly by a glacier that is unsorted and consisting of any grain size ranging from clay to boulders.
Total Dissolved Solids - Concentration of all substances dissolved in water (solids remaining after evaporation of a water sample).
Transmissivity - The rate at which water of a prevailing density and viscosity is transmitted through a unit width of porous medium under a unit hydraulic gradient. It is a function of properties of the liquid, the porous media, and the thickness of the unit and is the product of hydraulic conductivity and the saturated thickness of the aquifer (metres2/second).
Transpiration - Loss of water vapour from plants.
Trend - The relationship between a series of data points (e.g. Mann Kendall test for trend).
Upconing - In this study, the process in which dense salt water is vertically transported through less dense freshwater by means of a pressure gradient established by pumping. The process is named for the inverted cone shape of saline water that may form at the interface below a pumped well.
Water Balance - The flow of water in and out of a system.
Water Budget - A Water Budget uses simple accounting to compare how much water goes into and out of a system. When more water is taken out than is replenished, the system may experience stress.
Water Demand - Water demand is an estimate of actual water use.
Water Level - A measurement of depth to water in a well or an elevation of water in a water body or a well. It is made with water level tape or other sensor. Water level accuracy depends on how well the well collar is surveyed and other considerations.
Water Management - A framework to enable water planning, allocation and Framework management of water resources.
Water Management Plan - A plan that provides guidance for water management
and sets out clear and strategic directions for how water should be managed.
Water Use - Volume or rate of water diverted or withdrawn from a water body (e.g. a stream, lake, or groundwater aquifer) for use by humans on the land surface. Actual water use is determined through direct measurement.
Water Well - A hole in the ground for the purpose of obtaining groundwater; “work type” as defined by AEW includes test hole, chemistry, deepened, well inventory, federal well survey, reconditioned, reconstructed, new, old well-test.
Watershed - The geographic area of land that drains water to a shared destination. The boundary is determined topographically by ridges, or high elevation points. Water flows downhill, so mountains and ridge tops define watershed boundaries.
Watershed Stress Assessment - Water use is sustainable when supply and demand are in balance. When demand outstrips supply, a watershed can experience stress. Stress can also be seasonal and variable. Surface water stress compares the total demand and minimum conservation flows to the amount of natural water supply and storage.
Yield - A regional analysis term referring to the rate a properly completed water well could be pumped, if fully penetrating the aquifer: Apparent Yield: based mainly on apparent transmissivity, and Long-Term Yield: based on effective transmissivity.