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Water Budget

Water Budget, Conceptual Understanding

The latest version is 1.1.0 (February 2007, Revised October 2009)

The Water Budget Conceptual Understanding Report presents baseline data collected within the Raisin Region Conservation Authority (RRCA) and South Nation Conservation (SNC) during the course of Source Protection development. This report is the foundation of knowledge for building the necessary pieces of a source protection plan. Information provided in this report is presented by following the "Assessment Report: Guidance Module 7: Water Budget and Water Quantity Risk Assessment", developed by the MOE, October 2006.

Tier 1 Water Budget

The Tier 1 study builds upon the initial Conceptual Water Budget. The objectives of the Tier 1 study were to 1) identify the key pathways water follows to move through the SPR, and 2) to carry out a water quantity stress assessment to identify subwatersheds that show a surface water quantity or groundwater quantity stress. Subwatersheds assessed to have a water quantity stress and a municipal water supply system (surface water or groundwater) will be moved to a more refined analysis at the Tier 2 level.

Tier 2 Water Budgets

A Tier 1 water budget and water quantity stress assessment was completed for the entire Raisin-South Nation Source Protecting Region to broadly assess stress levels in all of the region’s subwatersheds. The report concluded that three subwatersheds are moderately to highly stressed in regard to municipal groundwater supplies and should be evaluated at a Tier 2 assessment level. The stressed subwatersheds were those for Garry River (Subwatershed #7), Greely (Subwatershed #29) and Winchester (Subwatershed #37). 

Tier 3 Water Budget - Local Area Risk Assessment

A Tier 3 assessment is carried out on all municipal water supplies located within the subwatersheds that are classified in the Tier 2 assessment as moderately and significantly stressed. A Tier 3 assessment is a more detailed study than the Tier 2 assessment and takes into account storage changes and water level fluctions on a daily scale. A Tier 3 assessment was undertaken for the Alexandria municipal surface water intake located in the Garry River watershed.