River Flow Modeling -
Visualizing Options

As human activities dramatically change the world, developing tools to predict the impact of what we do before we do it will help prevent unexpected or unwanted changes to our environment, whether from building dams, disposing waste, or exploring new forms of energy. The Battelle managed Pacific Northwest National Laboratory (PNNL) provides ways to predict these changes through its river modeling research. This form of computational fluid dynamics modeling helps decision makers understand how rivers, estuaries, and coastal environments are affected by natural and human influence.

"Our goal is to help decision makers and the public understand potential changes so they can make informed choices regarding solutions," said Marshall Richmond, who manages PNNL's river modeling research team, which focuses on two areas: water quality and fish passage. Researchers are currently studying how chemical and radionuclide contamination from waste disposal sites might affect the Columbia River. This water quality project, which is being conducted for the Department of Energy, uses computational modeling to show how contaminants can be expected to move through the water and sediments, and how contaminant concentrations will be affected by flows, tributary inputs, and reservoir operations. "We examine how the river system works today and then simulate different conditions and examine the effect that has on how contaminants move through the water," Richmond said.

"Flow lines, colored by water velocity (red for faster flow and blue for slower), depict a swirling flow pattern in front of the second powerhouse at Bonneville Dam. Images such as this provide the client with a better understanding of the complex flow environments present at their hydroelectric facilities."

In a study for the U.S. Army Corps of Engineers, PNNL researchers are exploring fish passage systems on the Columbia River. Fish migrating downstream typically swim close to the water surface, but fish that pass by the dam through the turbines have to swim deeper in the water column to reach the turbine entrances. The Corps is constructing a system at Bonneville Dam's second powerhouse to divert migrating juvenile salmon into a collector close to the water surface. Fish that pass through the collector are swept downstream of the dam, away from the turbines, through a sluiceway. PNNL's modeling of the complex three-dimensional water velocity patterns that affect the salmon as they approach the powerhouse is helping the Corps understand how the collector system will operate.

For both the water quality and fish passage models, PNNL researchers provide three-dimensional, animated presentations of the simulation data. "We have an array of tools we use to present the data in a form that bridges the worlds of fisheries, biology, civil engineering, and fluid dynamics science," Richmond said. "Tools like visualization are the best way to understand the immense amount of information gathered from a three-dimensional simulation."

For more information, contact Marshall Richmond, (509) 372-6241, marshall.richmond@pnl.gov or Joe Devary, (509) 376-8345, joe.devary@pnl.gov.