Upcoming Presentation

Climate Impacts Group Brownbag

When: Wednesday, March 16th

Time: 12:00 – 1:00 pm

Location: ACC 120

Title: Incorporating Climate Change Projections into Washington Department of Fish and Wildlife’s Water Crossing Design

Presenters: Jane Atha and George Wilhere, Washington Dept. of Fish and Wildlife

Abstract: The Washington Department of Fish and Wildlife (WDFW) provides technical guidance for the design of hundreds of fish passable water crossing structures that are constructed or repaired each year in Washington. In addition, WDFW permits fish passage structures on all lands except those covered under Forest Practice rules and designs fish passage structures for its own lands. None of WDFW’s actions ensure that the culvert designs meet high scientific standards to specifically account for changes in hydrology resulting from climate change. We evaluated the current WDFW culvert design and permitting decision process to identify design elements and decision points potentially sensitive to climate change impacts. We identified bankfull width as a primary culvert design criterion that was also sensitive to climate change. To determine how bankfull width might change in the future, we translated fine-scale hydrologic extreme projections across the state into predicted bankfull width estimates. We then derived bankfull width estimates at 1/16th grid cell resolution from the Variable Infiltration Capacity (VIC) hydrologic model simulation of historical stream discharge as well as for two time series (2030 – 2059 and 2070 – 2099) under the A1B climate scenario (a composite of ten climate models). For each grid cell, the agency can multiply the projected ratio of change, averaged over the ten models, to empirically measured bankfull width at a culvert site to determine projected changes in bankfull width. Cumulative distribution graphs illustrating the range of model projections of bankfull width estimates at grid cell resolution also allow the agency to quantify and assess climate-associated risk of fish passage culvert failure at an operational level.