A simple technique to estimate the far-field hydraulic impacts associated with the deployment of hydrokinetic devices is introduced. The technique involves representing hydrokinetic devices with an enhanced Manning (bottom) roughness coefficient. The enhanced Manning roughness is found to be a function of the Manning roughness, slope, and water depth of the natural channel as well as device efficiency, blockage ratio, and density of device deployment. The technique is developed assuming simple open channel flow geometry. However, once the effective bottom roughness is determined, it can be used to determine the hydraulic impact of arbitrary device configurations and arbitrary flow situations.
- Hydrokinetic (HK) devices can be represented with enhanced Manning roughness.
- The enhanced Manning roughness depends on the channel and HK device properties.
- HK device deployments lead to an increase in water depth and a decrease in flow velocity.
- Impacts to velocity, water surface elevation, and potential sediment transport can be estimated.