2 of Grant County to update and apply two hydrodynamic and water temperature models to quantify 94 years of water velocity, river stage, and water temperature in the Hanford Reach. To provide this needed data, Battelle was contracted by Public Utility District No. Because detailed hydrodynamic and water temperature data are very expensive to collect in the field, it is most cost effective to simulate such data using one- and/or two-dimensional physics-based models to provide data for the Hanford Reach. However, a thorough understanding of the mechanisms between salmon and Priest Rapids discharge is not possible without adequate data describing the physical characteristics (i.e., including fish habitat) of the river.
These discharge fluctuations are known to impact downstream fisheries consequently, many research studies have investigated the mechanistic relationships between fish and flow in the Hanford Reach.Ĭurrently, constraints on Priest Rapids Dam discharge are implemented to protect the freshwater life stages of Hanford Reach fall Chinook salmon. Relatively large diel fluctuations in discharge are required during some seasons to meet electricity demand and flood-control objectives. Priest Rapids Dam at river kilometer (rkm) 639.1 directly regulates flow into the Hanford Reach. The Columbia River upstream of the Hanford Reach is heavily regulated by upstream storage reservoirs (Grand Coulee Dam and several Canadian impoundments) and six run-of-river hydroelectric projects in the United States.
The Hanford Reach, located in south-central Washington State, is the only remaining unimpounded reach of the Columbia River in the United States upstream of Bonneville Dam. PNNL-26204, Pacific Northwest National Laboratory, Richland, Simulation of Columbia River Floods in the Hanford Reach. Waichler SR, JA Serkowski, WA Perkins, and MC Richmond. Suggested citation for this report is as follows: All of the output from the simulations have been archived and are available for future investigations in the Hanford Reach. The flooded area for the Standard Project Flood extends out of the channel area in some places, particularly in the 100-F Area. Floodplain maps show that for the 100-year and 500-year discharge levels, flooding is mainly confined to the topographic trench that is the river channel. The MASS1 output for water surface elevations was converted to the North American Vertical Datum of 1988 and projected across the channel and land surface to enable mapping of the floodplain for each scenario. The resulting water levels from the steady-state floods can be viewed as “worst case” outcomes for the respective discharge levels.
The simulated floods and their corresponding Columbia River discharges were 100-year (445,000 cfs), 500-year (520,000 cfs), and the USACE-defined Standard Project Flood (960,000 cfs). The discharge levels simulated were all low-probability events for example, a 100-year flood is one that would occur on average every 100 years, or put another way, in any given year there is a 1% chance that a discharge of that level or higher will occur. Army Corps of Engineers (USACE) for the Columbia, Snake, and Yakima Rivers, and a constant water level at McNary Dam, and then running the model to steady state. The flood flows for this study were simulated by setting constant flow rates obtained from the U.S. The existing MASS1 channel geometry and roughness and other model configuration inputs for the Hanford Reach were used for this study, and previous calibration and validation results for the model are reprinted here for reference. The current model setup can be used for other studies of flow, water levels, and temperature in the Reach. The MASS1 model of the Hanford Reach was previously calibrated to field measurements of water surface elevations. This report describes the hydraulic simulation of hypothetical flood flows using the best available topographic and bathymetric data for the Hanford Reach and the Modular Aquatic Simulation System in 1 Dimension (MASS1) hydrodynamic model. Columbia River water elevations and flows in the Hanford Reach affect the environment and facilities along the shoreline, including movement of contaminants in groundwater, fish habitat, and infrastructure subject to flooding.