Water Quantity Studies
The water budget and water quantity stress and risk assessments for the Halton Region and Hamilton Region Source Protection Areas help to develop an understanding of water availability, water movement, water uses, and water stresses within the Areas’ watersheds. They ultimately lead to a better understanding of the sustainability of the sources of municipal groundwater supplies. These assessments followed a tiered approach, with advancement to the next tier only applicable to those subwatersheds that are deemed stressed and that contain a municipal drinking water supply.
Water budget and water quantity stress assessments
Tier 1 is a simple assessment at a subwatershed scale to quantify the movement of both ground and surface waters across the entire source protection areas. This assessment determines the stress level in each subwatershed to meet the study year and the future demands. Only those areas identified as having potential water quantity deficiencies and including a municipal water supply were assessed in more detail.
Based on the water demand stresses identified, only two subwatersheds – Upper West Branch of Sixteen Mile Creek and Middle Spencer Creek - required a Tier 2 assessment. The Tier 2 required a more detailed look at the water budget of the subwatershed.
A full discussion of the water budget and water quantity stress assessment methodology and results is provided in the report:
Tier 1 Water Budget and Water Quantity Stress Assessment for the Halton-Hamilton Source Protection Region and Tier 2 Water Budget and Water Quantity Stress Assessments for the Upper West Branch of Sixteen Mile Creek and Middle Spencer Creek Subwatersheds, prepared by Halton-Hamilton Source Protection staff (2010)
This document includes reports on model development and vulnerability analyses prepared by Earthfx Incorporated for the Regional Municipality of Halton and the City of Hamilton.
Water budget and water quantity risk assessments
Because the two subwatersheds remained stressed following the Tier 2 assessment, Tier 3 water budget and water quantity risk assessments were required for the Kelso, Campbellville, and Greensville municipal groundwater supplies. A Tier 3 water budget and local area risk assessment focuses on the local area around the municipal wells and assesses the risk of the municipal supplies not having a sufficient quantity of water available to provide the existing and future populations.
The Tier 3 assessment of the Kelso and Campbellville water supplies is complete and the findings incorporated into the updated assessment report for the Halton Region Source Protection Area. The systems were deemed to be at moderate risk with no existing significant threats occurring. There are two reports that detail model development and calibration and the assessment of risk to the water supplies. They are available on the Technical Reports webpage. The policies that address potential future significant threats to the water supplies are included in the source protection plan.
The Tier 3 assessment of the Greensville water supply is also complete and the system was deemed to be low risk. The two reports are available on the Technical Reports webpage. No policies are necessary when a system is at low risk.
The City of Hamilton has installed additional wells in the Greensville area as proposed backup wells to the main source well. Additional modelling is underway to assess the impact these new water takings will have on the availability of source water and to delineate protection areas and identify existing and potential threats. When this additional work is complete the findings of the Greensville Tier 3 studies will be included in an amendment to the assessment report for the Hamilton Region Source Protection Area.