Application of a Routing Model for Detecting Channel Flow Changes with Minimal Data

Abstract

The discrete linear cascade model (DLCM) was applied for historical flow routing along the Nebraska City–Rulo section of the Missouri River in southeastern Nebraska. With the help of optimized model parameters it has been possible to identify the triggering mechanism responsible for historical changes in the stage-discharge relationship at Rulo over the 1952–2006 period, following construction of Gavins Point dam on the Missouri above Sioux City, Iowa. It was found that in the second part of the past century flood celerity in the study reach slowed by about 25%, most likely caused by an increase in the Manning roughness coefficient as a result of a large increase (almost a doubling) in the number of wing-dykes constructed over the reach within the same period. The ease of application and minimal data requirement (only discharge values at regular intervals) makes the DLCM a practical tool for stream-flow analysis. It also can serve as a preliminary investigative tool for more advanced and detailed hydraulic approaches that typically require a data-rich environment and significantly greater development time.