New Risk-Based Decision Support Tools for Designing Culverts for Fish Passage in a Changing Climate
Abstract
As part of a long-term collaboration to improve culvert design in a changing climate in the Pacific Northwest region, this project extends methods recently developed by the Washington State Dept. of Fish and Wildlife (WDFW) for designing culverts for fish passage under climate change. Specifically, based on analytical approaches recently developed at the University of Notre Dame (UND), researchers at the U. of Washington Climate Impacts Group, Skagit Climate Science Consortium, and the UND have developed an on-line prototype for a new design tool that estimates the probability that a proposed culvert design will fail to provide appropriate fish passage during its design lifespan. The tool works by estimating a required culvert size for fish passage for each future year in a culvert's design life using streamflow projections from an ensemble of ten CMIP3 climate change scenarios. Uncertainties in the future culvert size requirements are bootstrapped via Monte Carlo techniques, and a 95% confidence bound is established. If the required culvert size for a particular ensemble member and future design year exceeds a proposed design width with 95% confidence, then the scenario is counted as a fish passage "failure" for that climate ensemble member and future year. Finally, the number of scenarios that produce a fish passage failure are tallied for all ensemble members and future years to estimate the overall probability that a design failure will occur over the design lifespan. Users of the on-line tool select a location for the proposed culvert, a design lifespan, and a proposed culvert design width, and the tool calculates the probability of fish passage failure over the design lifespan. The tool can easily be adapted to incorporate alternate design criteria for culvert sizing, and also different levels of risk tolerance in the management community. In future work, the authors plan to work with WDFW and other research partners to refine the new tool and incorporate these new approaches in the official culvert design process used by WDFW for WA.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPA33F1206H
- Keywords:
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- 1916 Data and information discovery;
- INFORMATICSDE: 4324 Spatial decision support systems;
- NATURAL HAZARDSDE: 4328 Risk;
- NATURAL HAZARDSDE: 6309 Decision making under uncertainty;
- POLICY SCIENCES