Glossary of Terms

A glossary of some of the "scientific/technical" and/or "IT" jargon used in our SSI FWC project and more generally in SSI freshwater reporting.  For other general points on the terminology used, and on some of the science please have a look at "DataStream, A Monitor's Guide to Water" (Quality), and/or the Groundwater Foundation Glossary.

"Abstraction" (or "water withdrawals", or off-takes)

- sometimes used to reference freshwater taken from ground, or surface water sources, either permanently or temporarily.  This water is then moved to a place of use.  Cf. "Black Pipes" below.

"Aquiclude"

-  a (partly) subsurface geological unit, that may slowly absorb and hold water, but does not allow water movement or flow at a sufficient rate to supply creeks, springs, wells, etc.

"Aquifer" 

- a body of rock (hard, bedrock) or partially/unconsolidated sediment that holds groundwater. On Salt Spring Island the term "deep" aquifer or "shallow" aquifer (or well) are often used.  Deep being synonymous with groundwater pumped or flowing from "rock" aquifers (sediments or other hard rocks) accessed (abstracted) via drilled wells, or springs, shallow being groundwater from partially consolidated sediments (accessed via drilled wells, dug wells or springs).  Groundwater from aquifers naturally forms an important year-round component of freshwater flow, in island creeks, springs and lakes.BC aquifer groundwater budgets reporting (Hy-Geo Consulting, 2014) suggests that recharge for bedrock aquifers are often relatively direct precipitation independent, and instead are governed by infiltration of runoff /surface water into storage of the bedrock aquifer (Golder 2019).  Natural surface capture mechanisms (ecosystems) are important components of infiltration (and groundwater recharge).

"Aquifer subregions"

- capture a drainage system as well as subsurface aquifer “regions” and include bedrock geology, fault systems and major groundwater divides. The terminology is relevant to considerations investigating surface-to-subsurface freshwater interactions and studies, such as water budget and/or water balance analysis.

"Baseflow" 

- a background fresh groundwater inflow into a creek, often more noticable in the summer when surface run-off from rainwater (precipitation) is absent.  Baseflow (groundwater) is sourced from below the ground surface, from freshwater typically stored in rocks or sediments (an "aquifer").

"Baseline" 

- establishing what is a normal variability in a sampling set (eg chemistry, flow, other measurements) over time.

"Black Pipes" (and other creek off-takes, or abstraction)

- located in and running from creeks, ponds and lakes (surface freshwater bodies) all over the island.  In addition to water district supplies and groundwater wells, black pipes are/have been used to abstract surface freshwater for a variety of purposes, including irrigation, feeding livestock, fire suppression and for domestic house supplies.  In some cases the plans for abstraction were clearly more ambitious!  

Contaminate a surface freshwater body at someone's (or a local communities...) peril!

Chemistry (freshwater)

- freshwater chemistry is a broad subject area with freshwater "chemical components" (salt, sulphur, arsenic, mangesium manganese, etc!), from lakes, creeks, groundwater originating largely from the natural landscape.  The chemical components measured in freshwater (creeks, lakes, wells etc) are typicall influenced by "local" factors such as freshwater temperatures and pH,  these in-turn are influenced by geology (deep and shallow subsurface rocks, and soils) and surface ecosytems (groundcover; lakes where stratification or blending may occur), and/or urban and developed areas (road salt and other anthropogenic contaminates).  On Salt Spring Island we assume that most/all of the chemical variability in the island's freshwater is driven by the natural systems, though there are one or two possible exceptions...As an example of the influence of a natural landscape on freshwater chemistry - weathering of pyritic (suphides, often Fe2S) mudrocks (fine grained and clay-rich sedimentary rocks) may result in the oxidation of sulfides and in the generation of sulfates within the associated ground and/or surface water.  The nature and concentration of these, and other minerals, may be controlled by the mudrock type(s), there are many(!), and by the degree of exposure of these  rocks to ground water and/or surface water chemistry and through-flow.

"Cloud"

- a term used to refer to data stored in a remote location, not to be confused with clouds related to precipitation (aka rainfall).  Often, though not exclusively, cloud data is located in "data centres" around the world, and managed by one of the major/global IT companies.  Our SSIFWC project is a community data collection programme.  The data collected is a  cloud dataset centrally managed (along with many other datasets globally) via an Epicollect5 (software) interface, accessed either on our smartphone app or via a web browser. 

"Conductivity" or "EC" (electrical conductivity)

- a measurement of the electrical conductivity of freshwater.  Surface freshwater conductivities recorded to-date on the island (data collected easily in the field with an Oakton) are usually between 80 and 800 uS/cm (microseimens/cm).  In a natural setting creek and lake conductivities are affected primarily by the geology (rocks, sediments, soils) of the area through which the water flows (giving "groundwater signatures") and by precipitation (rainfall and or groundwater dilution signatures). Depending on the time of year one or both components may contribute to the measured conductivities measured in a stream. Discharges to streams (and conductivity) can also be negatively impacted by anthropogenic activities...

The USA EPA suggests that lower values (< 300μS/cm) protect aquatic life and higher values > 500μS/cm) may be detrimental to certain species of fish.

Useful background reading reference:  Conductivity and groundwater USA, Environment Protection Agency.  A FWC background reading article on this important topic and how it can be used in our island's citizen science project is in the works.

"Cross-section" 

- see "Profile" below

"Dissolved Oyxgen" (DO)

- dissolved oxygen (DO) refers to a concentration of oxygen gas in a body of water.  Oxygen enters water by direct absorption from the atmosphere, absorption is enhanced by turbulence (riffles, waterfalls) and lower water temperatures.  Water also absorbs oxygen released by aquatic plants during the process of photosynthesis. Sufficient DO is essential to growth/life. Useful background reading - the USA Environmental Protection Agency DO site.

"EC" (electrical conductivity)

- see "Conductivity" above

"Ecosystem"

- a geographic area where a community of organisms, as well as weather and landscape, interact as a cooperative system. Ecosystems contain biotic or living parts, as well as abiotic, or non-living parts. See also "Natural Ecosystem Services" below.

"Evapotranspiration"

- is the cumulative sum of water evaporation and plant transpiration from the Earth's land and ocean surfaces to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopies (forest, agricultural land etc), and from water bodies (creeks, lakes and ponds etc) depending on setting and climatic variations evapotranspiration can be very significant.

The variability in the evapotranspiration patterns on the island are a key variable in developing "water budget" models.

"GIS"

- a widely used abbreviation for a "Geographic Information System".  Essentially a GIS allows a user to "play with" any digital set of maps of interest, switching on and off discete map "layers" to look at how features relate to each other.  

GIS(s) are widely used in industry, academia , NGO's and government for data interpretation and planning.  Ideally planning is supported by "ground-truthed" maps... Simple web based GIS systems (or webmaps) include Google Maps, IT MAPIT and our SSIFWC to name a few, more eleborate "technical" GIS workspaces include Esri's ArcGIS and the open source (free) software package QGIS.

"Groundwater" 

- is freshwater sourced from below the grounds surface, from an "aquifer" or "reservoir". Groundwater is the word used to describe precipitation that has infiltrated through the soil below the surface and is stored underground.  Storage is typically in tiny pore spaces between grains in sediments, or within rocks, more unusual is storage in fractures - breaks in the rocks underground that allow water to be captured and to move.  

Groundwater may be characterised by an inverse relationship between water temperature and air temperature (air warm water cool and vice versa), the result of groundwater temperature remaining relatively constant during the course of the year, while air temperature changes seasonally.

Useful background reading reference: Wells & Groundwater (Canada.Ca, online) and Natural Process of Groundwater and Surface Water Interaction (USGS, online).

"Ground-truthing" (maps)

- is physically visiting a field area/site and determining if something on an interpretive map (with data and a map perhaps derived from a GIS), is actually as was/is predicted from "in-the-sky" observation systems, and/or from prior historical ground observations.

Ground-truthing is required in many situations as map products that are used "in planning" (estimates of surface, and sometimes subsurface, natural systems, and in urban and infrastrucutre characterisation) draw on "remote sensing" data derived from in-the-sky ground observation systems (satellites, aircraft, drones or other).  These remote systems developed maps do not (necessarily) give the right answer on what IS actually on the ground. 

Hydraulic Connectivity

-  for our island freshwater systems how surface water (rainfall in creeks, lakes, wetlands) interacts with soils, sediments and rocks, which freshwater can move into and through (via pore space, or fractures network), and vica versa! 

"LIDAR"

- can provide a hi-resolution image of the topography of the earth's surface.  It is often displayed as a bare-earth" (topography without vegetation) map backdrop and can provide very useful insights into (potential) waterbody positions and watershed boundaries (with suitable ground-truthing). The LIDAR acronym is derived from a "laser imaging, detection, and ranging" technique that accurately measures distances (ranges) by illumination of a surface with laser light and the measurements of this light's reflection.

Useful background reading reference: LidarBC the BC Open Lidar data portal

"Local Detail"

- for watershed field areas where volunteer numbers have grown (eg Weston Creek), and/or where more volunteer resources are willing/available for field work, "Local Detail" FWC data collection is being developed.  Local, more detailed data collection (at more sites, and/or more in-stream loggers) in these watershed areas provide additional insights into the watershed, the flow and chemistry variability in its' various stream catchments (particularly if we add-in local wells) and more baseline data.

Natural Ecosystem

- Various words can be used to describe this terminology " a biological community of interacting organisms and their physical environment, a complex network or interconnected system,  a place where the sum of the parts is greater than each part?  Our natural world (including our communities), with/without appropriate stewardship, is dependant on the health of these systems. 

"Natural Ecosystem Services"

- are the benefits to people from natural systems. These benefits include food, water purification, freshwater buffering, carbon sequestration, soil stabilization, recreation and cultural values, among others!

"Oakton"

- used (affectionately) to describe one of the basic, and simple to use field-tools used for quick, field chemistry, FWC data collection.  The Oakton chemistry measurements (water temperature, conductivity and pH) give useful insights into groundwater components in our islands streams (a water quantity parameter), and into water quality.  See also Oakton on our SSIFWC Field Equipment page.

"pH"

- pH is the measurement of the hydrogen-ion concentration in the water. There are numerous drivers that can influence pH levels, including both natural and anthropogenic sources - cf. our Background Reading "What is pH?" article, other useful reading - the USA Environmental Protection Agency pH site.

"Precipitation"

- largely synonymous with "rainfall" landing on the ground, as opposed to that which does not land (Virga).  On the island rainfall (mm/hour) is locally measured by a series of UVIC school weather stations eg at Gulf Island Secondary School.  Island rainfall is locally is orographic in nature, ie is strongly influenced by local topographic relief (hills, valleys, depressions) - increased precipitation is observed at higher topographic elevations, reflecting the effect that orographic lift has on precipitation... and minor rain shadows are observed in the leeward side of the higher elevation areas (Golder, 2019).

The variability in the rainfall patterns on the island are a variable in "water budget" models and more on-island weather stations are needed - interested(?) please contact the SSIFWC Project Lead.  
Note: - calculations of rainfall/precipitation in the various watershed notes assume (as an approximation only) that all points on the island receive 95cm of rainfall per year, the local variability is larger.  Scientific estimates of the volume of annual rainwater staying on the island range between <5% and ca 55%, with a weighting towards the former precentage remaining (recharge) number (Larocque, et al., 2015).

"Profile"

- a stream profile (also known as a stream cross-section), consists of a series of width and depth measurements across a stream, which can be used to calculate the stream area at a particular measured location.  Imagine taking a sharp knife and “cutting” through a stream bed (across the stream, at a representative and measurable point) this is the profile (cross-section). 

"Recharge"

- groundwater recharge (infiltration, deep drainage, deep percolation) is a hydrologic process, where water moves slowly downward from surface water into groundwater in an aquifer.  Recharge is the principle method through which water enters an aquifer.

"Reconnaisance (Scouting)"

- initial FWC field recordings undertaken to determine potential future watershed, and/or regular field sites.  The first (reconnaissance) visits to a field site capture "context-related" location data (eg ecosystems, canopy, water body type etc), to establish baseline data on a site, this enables us to understand the data collection setting and to monitor for change.

Springs

- the natural surface expression of a groundwater inflow.  Formed as a result of natural topographic variations (often geologically related), or where other excavations intersect a flowing body of groundwater at or below the local water table.  Below this point the subsurface aquifer is saturated with water (below the water table). 

"SSI FWC"

- the Salt Spring Island FreshWater Catalogue (SSI FWC) Project is an island-based community data collection programme aimed at developing a catalogue of SSI surface freshwater.  The FWC is a Water Preservation Society project. 

The FWC data collected is stored as a cloud dataset, centrally managed (along with many other datasets globally) by the Oxford University Big Data Institute.  Our data collection is captured using an Epicollect5 (software) interface supported by the Welcome Foundation.

For registered users our project data can be accessed/captured either via our Epicollect5 SSIFWC smartphone app or via an Epicollect5  web browser window. 

"SSIWPA" Salt Spring Island Watershed Protection Alliance 

- comprising a number of island, area districts and stewardship groups, and province agencies and government groups. See "Island Groups" for more details on this alliance and on other local interest groups.

Terroir

- the complete natural environment in which a particular wine is produced, including factors such as the soil, topography, and climate.  Freshwater is similarly influenced by the local terroir, depending on where this might be a mix of surface, near surface and deeper subsurface (groundwater).

"Town ("City", or "Public") Water"

- is filtered and treated to ensure a suitable community drinking water.  The term often invokes something that is somehow detached (distant) from the place we live, not often the case on an island. 

Vested (vs Unvested) freshwater

- vested water is that which is known to some extent (where government can include exemptions etc, a Known Known?) and can be managed via operational flexibility. Unvested water is unregulated, with potential operational risks with water use (a Known Unknown?).

"Water Balance"

- attempts to capture (reflect) the rate of change in water stored in an an area (a unit - e.g. a watershed or other catchment), including the rate at which water flows in and out of the unit.  A water balance is less elaborate than a water budget analysis. Cf this simple animated water balance calculator.

"Water Budget" 

- a tool used to help understand what freshwater resouces might be available in an area (for household use, community use and for ecosystem protection/maintainance).

Making a water budget calculation requires insights into "water INs", and "water OUTs", including precipitation, abstractions (lakes, wells, creeks), natural discharge flow-to-sea, and groundwater recharge.  

Cf. our Background Reading "Water Budgets" article.

"Watershed" (or sub-watershed) 

- is a land area that drains water into a particular "basin" or "catchment" area, for example - into a particular creek (there are no rivers on SSI !), lake, estuary or bay. A watershed is a land feature that can be identified by tracing a line along the highest elevations between two areas on a map (defining two or more basins).  Groundwater discharge is included in a watershed, although groundwater (aquifer) boundaries may not coincide exactly with surface water.  We have over 100 watersheds on SSI, cf. our recent Watersheds article on this subject.  

A sub-watershed is the area of land that water flows over, or through, to drain into a larger body of water within a larger watershed draining (for instance) to the sea.  A SSI sub-watershed example is St Mary Lake (wthin the larger Duck Creek watershed).

Cf. our Background Reading article on "Watersheds".

"Watershed Catchment Volumes" (& Recharge Efficiency)

- comparisons of the various SSI watersheds size and rainfall catchment volumes referred to in various parts of this website assume a constant 95cm of rainfall across the island.  Volume calculations are done using this basic, online, Volume of Rainfall calculator, area calculations use the CRD SSI Watersheds map.

With information on how much rainfall a watershed receives and how much water from a watershed discharges to the sea, and knowing something of evapotranspiration and groundwater discharge to sea, a simple "watershed recharge efficiency" may be determined.  Information on rainfall received, and watershed (sea) discharges, can be used in water balance modelling and in groundwater recharge modelling.

"Well"

- a mechanically drilled bored hole, or dug hole, allowing access to the subsurface, and shallow or deep aquifers (groundwater) respectively.  Well, groundwater, chemistry is an important parameter in improving our understanding of the linkages between surface water flow volumes, from precipitation (often containing a groundwater component), and groundwater per se (water stored in the ground over a longer period of time and not visibly flowing).

Well chemistry data is being collected at several sites in watersheds across the island.  This is to investigate further, surface (groundwater baseflow) water to groundwater calibration, and potential correlations between chemistry and groundwater inflow flow volumes in surface creeks - an imporant parameter in improving our understanding of...

"Wetlands"

- are areas where water covers the soil, is present either at or near the surface of the soil all year, or for varying periods of time during the year.  Wetlands play an important role in "regulation" of groundwater recharge/discharge and in key ecosystem maintainance - wetlands form an important part of natural "ecosystem services".