Glossary of Terms, Q – S

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Raw Water

Water that is in a drinking-water system or in plumbing that has not been treated in accordance with, (a) the prescribed standards and requirements that apply to the system, or (b) such additional treatment requirements that are imposed by the license or approval for the system.

Raw Water Supply

Water outside a drinking-water system that is a source of water for the system.


The exposed target in danger of incurring a potential impact. An example would be any aquifer or surface water body used for drinking water consumption.


Recharge is the process by which water moves from the ground surface, through the unsaturated zone, to arrive at the water table.

Regulated Areas

Those areas for which Conservation Authorities delineate and restrict land uses by making regulations under subsection 28(1) of the Conservation Authority Act. This subsection applies to water courses, streams, lakes, valleys, flood plains, and wetlands in Ontario.

Reliability Influence Area

A geographic area within which water users could have a possible influence on the reliability of a municipal water supply. For surface water intakes, the Reliability Influence Area would be defined as the total contributing drainage area to the intake. For groundwater, the area would be defined by subtracting the simulated groundwater levels under pumping conditions from those without pumping to estimate the drawdown of the municipal pumping system.

Reserve Amounts

Minimum flows in streams that are required for the maintenance of the ecology of the ecosystem.

Response Factor

Typical factors affecting the response include dilution, rate of discharge, absorption, and degradation of the contaminant or pathogen in question. Because of the nature of the water resource, certain contaminants and pathogens may not have an impact great enough to warrant concern or responsive action. The level of impact may not effectively degrade the water resource and therefore would not require a mitigative action.

Riparian Area

The area that lies as a transition zone between upland areas such as fields, etc. and streams, wetlands, lakes, rivers, etc. The zone is intermittently inundated and usually supports wet meadow, marshy or swampy vegetation.


The likelihood of a drinking water threat (a) rendering an existing or planned drinking water source impaired, unusable or unsustainable, or (b) compromising the effectiveness of a drinking water treatment process, resulting in the potential for adverse human health effects.

Security of well or intake infrastructure

An evaluation of structures/measures that are in place or are needed to protect a municipal groundwater supply well or surface water intake from potential contamination from external sources.


Describes an approach or methodology that uses measurable or ranked data, derived from both quantitative and qualitative assessments, to produce numerical values to articulate results.

Sensitivity Analysis

Sensitivity analysis evaluates the effect of changes in input values or assumptions on a model’s results.

Sensitivity Area

That portion of a defined vulnerable area that has been assigned a vulnerability score.


The degree to which an impact is measured compared to an idealized value of some parameter of concern. In the case of water quality, the severity may relate to degree of measurable exceedance of some contaminant or pathogen. In the case of water quantity deviation from some measurable parameter (e.g. minimum annual flow, piezometric head or lake level) must also be established.

Significant Hydrologic Features

(a) A permanent and intermittent stream, (b) wetlands, (c) kettle lakes and their surface catchment areas, (d) seepage areas and springs, and (e) aquifers and recharge aeas that have been identified as significant.


The most refined scale at which technical assessment of hydrological and hydrogeological conditions can be conducted. These assessments may contribute to water budgets, vulnerability assessments, and issues evaluation.


An area that is drained by an individual tributary into the main watercourse of a watershed.

Surface to Aquifer Advection Time (SAAT)

The average time required by a water “particle” to travel from a point at the surface to the aquifer of concern. The SAAT is approximated by using the vertical component of the advective velocity integrated over the vertical distance and the average porosity.

Surface to Well Advection Time (SWAT)

The average time required by a water “particle” to travel from a point at the ground surface to the well, including both vertical and horizontal movement.

Surface Water

Water that is present on the earth’s surface and may occur as rivers, lakes, wetlands, ponds, etc.

Surface Water Intake Protection Zone (IPZ)

The contiguous area of land and water immediately surrounding a surface water intake, which includes:
•the distance from the intake;
•a minimum travel time of the water associated with the intake of a municipal residential system or other designated system, based on the minimum response time for the water treatment plant operator to respond to adverse conditions or an emergency;
•the remaining watershed area upstream of the minimum travel time area (also referred to as the Total Water Contributing Area) – applicable to inland water courses and inland lakes only


Wooded wetlands with 25% cover or more of trees or tall shrubs. Standing to gently flowing waters occur seasonally or persist for long periods on the surface. Many swamps are characteristically flooded in spring, with dry relict pools apparent later in the season.

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