ECWP Significant Groundwater Recharge Areas

Polygon file displaying significant groundwater recharge areas (SGRA) across the Toronto Region Source Protection Area (TRSPA) in the CTC Region.

The SGRA layer was developed to satisfy requirements of the Source Protection Plan for the Credit Valley, Toronto and Region and Central Lake Ontario region (CTC-SPC 2015) under the Clean Water Act (2006). Groundwater recharge occurs when rain/snow seeps down into an aquifer and generally this is associated with particular soil types (e.g., loose sand/gravel). SGRAs are delineated using a water budget modelling process, where the high potential recharge areas are delineated by the method outlined in full in CTC-SPC (2015). Details of the methodology used to develop this layer can be found in CTC-SPC (2015).

SGRAs have permeable soils such as sand or gravel that allow the water to soak easily into the ground. Under the Clean Water Act, 2006, a recharge area is considered significant when it helps maintain the water level in an aquifer that supplies drinking water (including private wells), and has higher than average recharge across the Source Protection Area. SGRA are provided with vulnerable scores at the 2, 4 and 6 level. (Areas with a score of 2 are least vulnerable to contamination and areas with a score of 6 are most vulnerable).

This file was updated in 2018 and was approved as part of CTC's first Sec34 amendment in 2019.

Entity Name: SW Significant Groundwater Recharge Area

Table Name: SignificantGroundwaterRechargeArea

An area can be considered a significant groundwater recharge area if (1) the area annually recharges water to the underlying aquifer at a rate that is greater than the rate of recharge across the whole of the related groundwater recharge area by a factor of 1.15 or more; or (2) the area annually recharges a volume of water to the underlying aquifer that is 55% or more of the volume determined by subtracting the annual evapotranspiration for the whole of the related groundwater recharge area from the annual precipitation for the whole of the related groundwater recharge area.

#

ATTRIBUTE/COLUMN NAME

DATATYPE

REQ

DESCRIPTION

1

OBJECTID

OBJECTID

NUMBER(13)

Yes

A unique numeric identifier assigned to each feature.

2

Source Protection Area ID

SPP_ID

NUMBER(2)

Yes

Identifier for the source protection area that provided the original data about the feature. SPP_ID values range from 0 to 48 chosen from Lookup Table: SOURCE_PROT_AREA_LIST.

3

Vulnerability Score

VULNERABILITY_SCORE

NUMBER(1)

Yes

Ranges from 2, 4 or 6, with 6 being most vulnerable. Technical rules outline how to assign this, typically based on the Time of Travel zone and/or the relative Vulnerability Level.

4

Effective Datetime

EFFECTIVE_DATETIME

DATE

Yes

Date/time the record was created or last modified in the source database.

5

SHAPE

SHAPE

SDO_GEOMETRY

Yes

Geometry attribute.

Clipping SGRAs

The jurisdictional identification of SGRA was approved by the SPC. However, Technical Rule (45) requires that “an area shall NOT be delineated as a SGRA area unless the area has a hydrological connection to a surface water body or aquifer that is a source of drinking water for a drinking water system.” This includes private systems (O. Reg. 170/03). This Technical Rule introduces the idea of clipping out SGRAs that are of no significance from a drinking water point of view, since it would not make practical sense to protect them. These areas may be important in other contexts, but they are not considered significant under the CWA. In the CTC Region, the SGRA located within the municipal service boundary that are on the Lake Ontario shoreline and sourced from Lake Ontario have been clipped out if no drinking water systems (as defined in the Safe Drinking Water Act, 2002) depend on those SGRAs.

Datasets available for download

Additional Info

Field Value
Last Updated August 15, 2026, 07:14 (UTC)
Created May 19, 2026, 16:32 (UTC)
Domain / Topic
Domain or topic of the dataset being cataloged.
Title
Title for the Dataset.
ECWP Significant Groundwater Recharge Areas
Description
A description of the dataset.

Polygon file displaying significant groundwater recharge areas (SGRA) across the Toronto Region Source Protection Area (TRSPA) in the CTC Region.

The SGRA layer was developed to satisfy requirements of the Source Protection Plan for the Credit Valley, Toronto and Region and Central Lake Ontario region (CTC-SPC 2015) under the Clean Water Act (2006). Groundwater recharge occurs when rain/snow seeps down into an aquifer and generally this is associated with particular soil types (e.g., loose sand/gravel). SGRAs are delineated using a water budget modelling process, where the high potential recharge areas are delineated by the method outlined in full in CTC-SPC (2015). Details of the methodology used to develop this layer can be found in CTC-SPC (2015).

SGRAs have permeable soils such as sand or gravel that allow the water to soak easily into the ground. Under the Clean Water Act, 2006, a recharge area is considered significant when it helps maintain the water level in an aquifer that supplies drinking water (including private wells), and has higher than average recharge across the Source Protection Area. SGRA are provided with vulnerable scores at the 2, 4 and 6 level. (Areas with a score of 2 are least vulnerable to contamination and areas with a score of 6 are most vulnerable).

This file was updated in 2018 and was approved as part of CTC's first Sec34 amendment in 2019.

Entity Name: SW Significant Groundwater Recharge Area

Table Name: SignificantGroundwaterRechargeArea

An area can be considered a significant groundwater recharge area if (1) the area annually recharges water to the underlying aquifer at a rate that is greater than the rate of recharge across the whole of the related groundwater recharge area by a factor of 1.15 or more; or (2) the area annually recharges a volume of water to the underlying aquifer that is 55% or more of the volume determined by subtracting the annual evapotranspiration for the whole of the related groundwater recharge area from the annual precipitation for the whole of the related groundwater recharge area.

#

ATTRIBUTE/COLUMN NAME

DATATYPE

REQ

DESCRIPTION

1

OBJECTID

OBJECTID

NUMBER(13)

Yes

A unique numeric identifier assigned to each feature.

2

Source Protection Area ID

SPP_ID

NUMBER(2)

Yes

Identifier for the source protection area that provided the original data about the feature. SPP_ID values range from 0 to 48 chosen from Lookup Table: SOURCE_PROT_AREA_LIST.

3

Vulnerability Score

VULNERABILITY_SCORE

NUMBER(1)

Yes

Ranges from 2, 4 or 6, with 6 being most vulnerable. Technical rules outline how to assign this, typically based on the Time of Travel zone and/or the relative Vulnerability Level.

4

Effective Datetime

EFFECTIVE_DATETIME

DATE

Yes

Date/time the record was created or last modified in the source database.

5

SHAPE

SHAPE

SDO_GEOMETRY

Yes

Geometry attribute.

Clipping SGRAs

The jurisdictional identification of SGRA was approved by the SPC. However, Technical Rule (45) requires that “an area shall NOT be delineated as a SGRA area unless the area has a hydrological connection to a surface water body or aquifer that is a source of drinking water for a drinking water system.” This includes private systems (O. Reg. 170/03). This Technical Rule introduces the idea of clipping out SGRAs that are of no significance from a drinking water point of view, since it would not make practical sense to protect them. These areas may be important in other contexts, but they are not considered significant under the CWA. In the CTC Region, the SGRA located within the municipal service boundary that are on the Lake Ontario shoreline and sourced from Lake Ontario have been clipped out if no drinking water systems (as defined in the Safe Drinking Water Act, 2002) depend on those SGRAs.

Tags / Keywords
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Format (CSV, XLS, TXT, PDF, etc)
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Dataset Size
Dataset size in megabytes.
104.0
Metadata Identifier
Metadata identifier – can be used as the unique identifier for catalogue entry
Published Date
Published date of the dataset.
2022-01-07
Time Period Data Span (start date)
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Time Period Data Span (end date)
End date of time data in the dataset.
GeoSpatial Area Data Span
A spatial region or named place the dataset covers.
Field Value
Access category
Type of access granted for the dataset (open, closed, service, etc).
public
License
License used to access the dataset.
Toronto and Region Conservation Authority (TRCA) Open Data Licence v1.0 - Toronto and Region Conservation Authority (TRCA)
Limits on use
Limits on use of data.
Location
Location of the dataset.
https://trca-camaps.opendata.arcgis.com/datasets/camaps::ecwp-significant-groundwater-recharge-areas-1
Data Service
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Owner
Owner of the dataset.
trca_d.macleod
Contact Point
Who to contact regarding access?
Conservation Ontario
Contact Point Email
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[email protected]
Publisher
Publisher of the dataset.
Conservation Ontario
Publisher Email
Email of the publisher.
Author
Author of the dataset.
trca_d.macleod
Author Email
Email of the author.
Accessed At
Date the data and metadata was accessed.
2025-08-08
Field Value
Identifier
Unique identifier for the dataset.
a3439d2d507f47b6a0c7bf57ae3828be
Language
Language(s) of the dataset
English
Link to dataset description
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https://trca-camaps.opendata.arcgis.com/datasets/camaps::ecwp-significant-groundwater-recharge-areas-1
Persistent Identifier
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Globally Unique Identifier
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Contains data about individuals
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Contains data about identifiable individuals
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Contains Indigenous Data
Does the data hold data about Indigenous communities?
Portal Type
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Field Value
Version
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None
Source
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None
Version notes
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Is version of another dataset
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Other versions
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Provenance Text
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Conservation Ontario
Provenance URL
Provenance URL of the data.
Temporal resolution
Describes how granular the date/time data in the dataset is.
GeoSpatial resolution in meters
Describes how granular (in meters) geospatial data is in the dataset.
GeoSpatial resolution (in regions)
Describes how granular (in regions) geospatial data is in the dataset.
Field Value
Indigenous Community Permission
Who holds the Indigenous Community Permission. Who to contact regarding access to a dataset that has data about Indigenous communities.
Community Permission
Community permission (who gave permission).
The Indigenous communities the dataset is about
Indigenous communities from which data is derived.
Field Value
Number of data rows
If tabular dataset, total number of rows.
33
Number of data columns
If tabular dataset, total number of unique columns.
5
Number of data cells
If tabular dataset, total number of cells with data.
165
Number of data relations
If RDF dataset, total number of triples.
Number of entities
If RDF dataset, total number of entities.
Number of data properties
If RDF dataset, total number of unique properties used by the triples.
Data quality
Describes the quality of the data in the dataset.
Metric for data quality
A metric used to measure the quality of the data, such as missing values or invalid formats.

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