Author(s): Tonina Daniele; Charles H. Luce; Frank P. Gariglio
Linked Author(s): Daniele Tonina
Keywords: Hyporheic fluxes; Stream temperature; Erosion and deposition
Abstract: The hyporheic zone is the volume of sediment saturated with mostly stream water. It is an important ecotone, where macro-invertebrates use the void among particles and salmon eggs incubate. It is also an important transformation zone for reactive solutes, where streambed sediment filters stream waters. Here, we investigate the hyporheic zone spatio-temporal variations of a pool-riffle sequence, where Chinook salmon and steelhead trout spawn. We use a novel method based on time series analysis of stream and hyporheic water temperatures. The new model allows us for the first time to simultaneously monitor hyporheic fluxes, thermal regime of the hyporheic zone and changes in stream bed surface elevations. The last provides a mean to control the sediment stability of the pool-riffle sequence for erosion and deposition. Our results show that this pool-riffle is a stable feature with negligible scour near the areas where salmonids spawn. Downwelling fluxes are present at the upstream side of the riffle where redds may be located and their magnitude varies with discharge and season.
Year: 2013