ClimateChange Assessment Guide.pdf - University of Waterloo

E-50Guide for Assessment of Hydrological Effects of Climate Change in Ontariosource for the water demand estimate was the Ministry of Environment’s (MOE) Permits to Take Water (PTTW)database that contains records of the permitted water users located within the watershed.Consumptive water use refers to an estimate of the volume of water that is not returned to its source by a water takingoperation. Consumptive use rates were estimated for each PTTW by applying published seasonal and consumptionfactors to all permits. Wherever available, reported water taking rates were used in this analysis. While nonpermittedwater takings (e.g., rural residential takings) are considered to be less significant than permitted takings onthe overall watershed water budget, these takings were still included in the water demand estimates.The Tier Two water budget study estimated consumptive groundwater and surface water demands for eachsubwatershed. Table 7-2 summarizes the estimated consumptive groundwater use across the entire Credit RiverWatershed.Table 7-2: Average annual consumptive groundwater for the Credit River Watershed.Water Use CategoryAverage Annual Consumptive Groundwater Usem 3 /dPercent of TotalMunicipal 26,957 69%Aggregate 7,780 20%Rural Domestic 1,549 4%Other 1,752 4%Golf Course 941 2%Agriculture 411 1%Bottled Water 225 1%Total 39,615 100%As summarized in Table 7-2 above, municipal supplies represent the largest proportion of groundwater use in thewatershed, with these demands being concentrated in several municipalities including the Town of Orangeville(Subwatershed 19) and the Towns of Acton and Georgetown (Subwatersheds 10 and 11). The Tier Two Stress Assessment was completed using groundwater supply estimated using the watershed’scalibrated surface water and groundwater flow model as well as the consumptive water demand estimates for eachsubwatershed. Figure 7-1 illustrates the results of this assessment for each subwatershed.