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Deep Engagement with Southern California Water Managers: Simulating Future Storms to Stress Test Systems

Presentation Date
Monday, December 14, 2020 at 4:28pm



In a region with substantial historical precipitation variability and water sustainability challenges, the additional challenge of anticipating climate change impacts can seem mired in too much deep uncertainty to justify action. Still stakeholders engaged in water management decisions seek the input of experts on regional climate change. Often under outside mandate, they expect to update current standards which are based on historical statistics. Thus the statistics of climate changes are frequently the starting point for inquiries. We demonstrate how a new regional climate simulation dataset is already informing a shift from statistics towards stress tests of systems based on a wide range of possible future conditions. We speculate that such an approach, combined with the deep engagement of communicating processes and limitations, can advance both scientific understanding and technical capacity to act on that information. Examples will be shared of recent scientific efforts to produce plausible stress test cases based on an unprecedented regional downscaling effort using the WRF model driven by CMIP6 simulations from a range of GCMs, scenarios, and realizations. We search for simulated wet and dry conditions that fall outside of what has been experienced in the period that agencies have been operating. Partner agencies can then use these as the basis for storylines that test operational sensitivity. It remains difficult to escape the question of how likely conditions resembling a given storyline are to transpire within a particular time frame. We highlight some approaches to communicating expansions to the magnitude of potential hydrologic events, even as irreducible limits exist for projections of timing and sequencing.

Funding Program Area(s)