Citation | Jost, G and Weber, F. 2012. Hydrologic Impacts of Climate Change; Integrated Resource Plan Appendix 2C. BC Hydro |
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Organization | BC Hydro |
URL | https://www.bchydro.com/content/dam/BCHydro/customer-portal/documents/corporate/regulatory-planning-documents/integrated-resource-plans/current-plan/0200c-nov-2013-irp-appx-2c.pdf |
Abstract/Description or Keywords | This document provides an introduction to the science of climate change and its impact on the hydrology in British Columbia, and summarizes the implications of historical and future climate change on the water cycle and water availability in watersheds managed by BC Hydro. This document uses the IPCC definition of climate change, which is "a change in the state of the climate that can be identified (e.g., using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. It refers to any change in climate over time, whether due to natural variability or as a result of human activity." As part of BC Hydro's climate change adaptation strategy, BC Hydro has been working with some of the world's leading scientists in climatology, glaciology, and hydrology to determine how climate change has affected the water supply and what we can expect in the future. BC Hydro has formed partnerships with the Pacific Climate Impacts Consortium (PCIC) and the Western Canadian Cryospheric Network (WdN). In addition, BC Hydro has conducted internal studies to investigate historic impacts of climate change on inflows. When working with climate change scenarios it is important to realize that the goal of working with scenarios is not to predict the future, but to better understand uncertainties in order to reach decisions that are robust under a wide range of possible futures. The hydrologic climate change impact studies that were commissioned by BC Hydro included a comprehensive assessment of uncertainties in predictions for the 2050s that considered uncertainties in general circulation modeling, hydrologic modeling, and uncertainties in possible emission trajectories. Despite substantial uncertainty in the magnitude of projected changes, there is a general consensus of the direction of climate change: ii • Historical trends in annual reservoir inflows are small and not significant. There is some evidence for a modest historical increase in annual inflows into BC Hydro's reservoirs. • There is evidence for historical changes in the seasonality of inflows. Fall and winter inflows have shown an increase in almost all regions; there is weaker evidence for a possible modest decline in late-summer flows for those basins driven primarily by melt of glacial ice and/or seasonal snowpack. • For the period of inflow records (35 to 47 years, depending on the reservoir), the severity of year-to-year fluctuations in annual reservoir inflow volumes has not changed. • Projected warming in the 21st century shows a continuation of patterns similar to those of recent decades. • All emission scenarios project higher temperatures in all seasons in all areas of British Columbia during the 21st century that will very likely be larger than those observed during the 20th century. Precipitation projections suggest likely increases in winter, spring, and fall for all study areas under all scenarios. • A modest increase in annual water availability is likely for BC Hydro's hydroelectric system. • Annual discharge in most Upper Columbia watersheds is projected to likely increase. • In the Columbia and Kootenay regions, late fall and winter flows will increase slightly; the onset of the snowmelt freshet will be earlier; spring a.nd early-summer flows will be substantially higher; earlier peak flows and higher monthly peak flows can be expected; and late-summer and early-fall flows will be substantially lower. • Annual discharge is projected to increase in the Peace region, where late-fall and winter flows will increase slightly; the snowmelt freshet will begin earlier due to higher spring temperatures; and summer flows will be lower. • Snow processes on the South Coast will become less important to the hydrology of tlie watersheds; fall and winter flows will increase, with a larger fraction of precipitation falling as rain; and spring and summer flows will decrease. • The Campbell River area will see negligible changes to annual discharges. The hydrological impact studies constitute the first step in BC Hydro's climate change adaption strategy: identify current and future climate changes relevant to the system. Next steps are to assess the vulnerabilities and risks to climate change across the BC Hydro system and then to develop an adaptation strategy using risk-based prioritization schemes. The BC Hydro Adaptation Working Group will determine where there may be vulnerabilities to climate change, and then specific hydrologic scenarios will be input into existing planning models that simulate the current and future operation of the Generation system to assess whether the operation of the system might need to be adapted in the future. |
Information Type | report |
Regional Watershed | Province |
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Project status | complete |
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