Development of Stage-Discharge Relations for Ungaged Bridge Waterways inWestern Iowa

Stage-discharge relations constitute a viable, alternative technique for estimating accurately flow for ungaged sites. In this research, the authors have utilized pressure transducers and Large Scale Particle Image Velocimetry techniques to develop stage-discharge relations at eleven sites in the Hungry Canyon Area (HCA) of southwestern Iowa under different hydrologic conditions. They have employed these data to calibrate and verify an established hydrologic model and then they have used this model to provide a stage-discharge relation for different hydrologic conditions (i.e. rating curves). The benefits of the project are numerous including that the discharge data will be used for a number of purposes, including operational decision making in the HCA about the design of water-control and conveyance structures, input for hydraulic and hydrologic models, and calculation of sediment and other water-quality constituents transport and “loads”, and for decision making. This project has also pointed out the difficulties in measuring flows in ungaged streams with ice jams, steep banks, erodible beds, and floating debris.