ClimateChange Assessment Guide.pdf - University of Waterloo

Background15in evapotranspiration and lower summer streamflowdue to climate change, agricultural operations thatrely on irrigation may be required to irrigate earlier inthe growing season, and more frequently throughoutthe year. Other water users such as municipalities, golfcourses and industries may also experience increasedwater requirements due to higher temperatures, higherpotential evapotranspiration, and less frequent rainfallevents. Water allocation issues caused by an increase inwater demand may be exacerbated by reduced wateravailability (streamflow) during low flow seasons.To date, within the Province of Ontario, only a smallnumber of large-scale water allocation plans havebeen undertaken. This is gradually changing with theidentification of “High Use Watersheds” by the MOE;whereby, water taking proposals in watersheds with highrelative water use require additional scrutiny. The PTTWprogram, traditionally focused on local impacts of welldrawdown and stream interference, is moving towardslarger basin-scale water management plans. Shouldthis trend continue and basin-scale water allocationplanning be undertaken province-wide, investigationswill be required to determine water availability underfuture climates and under additional stresses anddemands; such as those associated with populationgrowth and changes in consumptive patterns, land use,and vegetation. In fact, water allocation in the futureneeds to be flexible and under regular review as climatechange will likely exert a non-steady influence uponhydrologic systems over time.2.3.3 Subwatershed PlanningIn the Province of Ontario, municipalities, developersand conservation authorities work cooperatively todevelop and implement subwatershed plans. Thesubwatershed planning process involves an integratedteam of planners, scientists, engineers and the publicto develop environmentally sound approaches toguide land use planning and development decisions.Subwatershed plans are developed to:• Promote an ecosystem approach to environmentalplanning in the watershed;• Foster early integration of environmental andecosystem considerations in preparation of land useplans;• Assist municipal and government agencies,consultants and the development industry inunderstanding the ecological needs of the watershed;and• Enhance the efficiency and effectiveness of land useplan preparation and review process.Future subwatershed plans developed in the Provincewill need to account for potential hydrological andecological impacts of climate change and exploreadaptation options. These plans will be required toassess the impact of recent climate change and futureclimates, especially as these assessments can informmanagement planning and policy adaptation processes.Water resource assessments at the subwatershed scaleare very important to the management of aquatic andterrestrial flora and fauna in addition to human needs.2.3.4 Environmental Monitoring ProgramsEnvironmental monitoring in the Province of Ontariois carried out by a number of agencies. While existingmonitoring networks were designed to facilitate thecharacterization and understanding of the systems asviewed in the past, these networks may be inappropriatefor future water resource management. The variousenvironmental monitoring programs within the Provinceare listed in Box 2.1, with recommendations formodifications to the various programs.2.3.5 Stormwater ManagementMunicipalities in Ontario prepare stormwatermanagement (SWM) master plans to develop longtermstrategies for the safe and effective managementof stormwater runoff from urban areas along withprotection of ecosystem health and assurance ofecological sustainability of receiving waters. A SWMmaster plan approach integrates flood control,groundwater and surface water quantity and qualitymanagement, ecosystem protection, and systemdrainage issues.Municipalities complete a SWM master plan inaccordance with the Municipal Class EnvironmentalAssessment planning and design process (October2000, as amended in 2007). A SWM master plan maybe prepared to guide a municipality’s storm watermanagement planning over a long period of time (+25years). Moving ahead, the process must consider thepotential impacts of climate change; the impacts thatmay affect the magnitude and frequency of flooding