Water Budgets

Tier 2 Water Budget and Ecologically Significant Groundwater Recharge Areas (ESGRA) Studies

The Lake Simcoe Protection Plan (LSPP) requires Tier 2 Water Budget Studies to be completed for all subwatersheds within the Lake Simcoe Basin that were not previously completed through Source Water Protection initiatives.

This requirement is part of an initiative to monitor progress in achieving the water quantity-related objectives of the Lake Simcoe Protection Plan; namely, to support the maintenance of adequate flows to maintain healthy aquatic ecosystems in the Lake Simcoe watershed.  In addition, the LSPP aims to identify and protect primary Ecologically Significant Groundwater Recharge Areas (ESGRAs) that sustain discharge to important surface water features within subwatersheds such as streams and wetlands.

Ecologically Significant Groundwater Recharge Areas (ESGRAs) are identified as areas of land that are responsible for supporting groundwater systems that sustain sensitive features like coldwater streams and wetlands. To establish the ecological significance of the recharge area, a linkage must be present between the recharge area and the Ecologically Sensitive Feature (e.g. a reach of a coldwater stream, a wetland, or an Area of Natural or Scientific Interest (ANSI)).

The identification of an ESGRA is not related to the volume of recharge that may be occurring, rather they represent pathways in which recharge, if it occurred, would reach that feature. While delineating ESGRAs is an important task in establishing the linkage between a recharge area and an Ecologically Sensitive Feature it is not a certainty that ESGRAs will coincide with SGRAs, as they may not support high volumes of recharge.  While ESGRAs and SGRAs are not mutually exclusive, the areas where they do coincide support high volumes of recharge and Ecologically Sensitive Features.

An initial study carried out by Earthfx Inc. (2012) provided an outline for the methodology to be carried out for this and subsequent ESGRA studies.

Tier 3 Water Budget and Local Area Risk Assessments

Under the requirements of the Clean Water Act, municipalities may be required to complete a Tier Three Water Budget and Local Area Risk Assessment (Tier Three Assessment) to assess the ability of the municipal water sources to meet committed and planned water demands. Tier Three Assessments are required where municipal wells or intakes are located in subwatersheds that were classified as having a Moderate or Significant stress level as part of a Tier Two Subwatershed Stress Assessment completed under the requirements of the Clean Water Act.

The Tier 3 Assessments identify municipal wells or intakes that may be unable to meet their allocated water demands under average or drought conditions.