Author(s): Daniele Tonina; Charles H. Luce; Aston Carpenter; Timothy Deweese
Linked Author(s): Daniele Tonina
Keywords: No Keywords
Abstract: Streambeds are in constant dynamic equilibrium with flow discharge and upstream sediment inputs. Monitoring their changes in elevations is challenging due to difficulty of measuring transient erosion-deposition processes especially during high flows. However, it is extremely important to monitor scour and deposition for risk assessment of hydraulic structures, such as bridges and levee, for river restoration, for studying and understanding streambed morphology evolution and quantify the effect of flow releases. Here we tested a new method based on temperature time series of surface and streambed sediment pore waters to monitor streambed scour and deposition and hyporheic fluxes continuously at the daily time scale. Stream flow temperatures provide a natural tracer to study interaction between stream and pore waters. Whereas the naturally occurring daily stream water temperature oscillations has been used to quantify hyporheic fluxes in streams for several years, its application to monitor streambed elevation is recent. Here, we tested it to quantify temporal variations of the streambed elevations. The method uses the changes in amplitude and phase of the daily temperature oscillations between the surface water and the time lagged stream water flowing within the streambed sediment. Application of the method during high flow conditions shows that the method predicts the magnitude of scour and fill. This provides a new effective, easy to use and inexpensive methodology to monitor temporal evolution of erosion and deposition patterns in rivers.
Year: 2018