ClimateChange Assessment Guide.pdf - University of Waterloo

E-56Guide for Assessment of Hydrological Effects of Climate Change in Ontario The following are recommendations based on the climate change impact assessment for Subwatershed 19:• Data gaps should be filled to reduce uncertainties within the hydrologic modelling exercises and climatechange impact assessment. Key data gaps are itemized below in terms of the intensity and spatial extent ofstreamflow and meteorological monitoring. Improvements in these areas allow for more spatially detailedmodel calibration. Another data gap relating to climate change impact assessment includes estimates offuture rainfall intensity, duration and frequency that, if available, would allow simulation of peak flow response.• Low temperature and winter evapotranspiration should be investigated within Subwatershed 19 to ensure thatthis component of the water balance is accurately represented.• Continuously monitoring streamflow gauges should be established at representative tributary sites so thatheadwater tributaries can be calibrated. Recommended sites include the outlet of Island Lake and near themouths of Monora Creek and Mill Creek as a minimum.• Solar radiation, cloud cover, evaporation (daily) and precipitation (hourly) should be monitored in or nearIsland Lake.• Downscaling techniques were applied to address the potential effects of changes in climate variability;however, these methods may not be practical if drizzle effect is observed in datasets, as in this case study.• The climate change impact assessments should be reevaluated as new information becomes available, suchas improved downscaling techniques, including Regional Climate Model (RCM) scenarios.• Climate change adaptation methods for Subwatershed 19 should consider methods to increase groundwaterrecharge (i.e., infiltration) and reduce surface runoff as these processes may change in the future.• If climate change leads to intensification of storm events, there flood prone areas may be higher risk of floods.It is recommended that adaptation measures should be identified to minimize flood risk in these areas.• Water management in Subwatershed 19 should minimize water taking in summer months, shiftingwithdrawals to winter periods, where possible.• A list of potential adaptation measures should be developed for Subwatershed 19 and these should be testedin a feasibility study. In general, potential adaptation measures should include those that retain water in thesubwatershed as groundwater or in wetlands, reducing surface runoff and promoting recharge year round;those that reduce summer stream warming which stresses aquatic habitat and elevates evaporation rates;and those that promote water conservation to reduce water demand and groundwater pumping.• Island Lake water management should be evaluated in a climate change impact assessment with specificregards to its capability to provide augmenting flow and recreational habitat into the future.