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A little bit more detail on individual research outputs, field campaigns, comings and goings, and goings on ...

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October 2017. Article published in Journal of Geophysical Research - Earth Surface

Multibeam acoustic backscatter has considerable utility for remote characterization and mapping of spatially heterogeneous bed sediment composition over vegetated and unvegetated mixed sand-gravel riverbeds of mixed sand and gravel from a moving vessel.

However, high-frequency, high-resolution acoustic backscatter collected in shallow water is hampered by significant topographic contamination of the signal. In this paper, a two-stage method is proposed to filter out the small-scale topographic influence on acoustic backscatter. This process strengthens relationships between backscatter and sediment composition.

A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

 
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September 2017. Presented at the Rivers, Coastal and Estuarine Morphodynamics ("RCEM 2017") Symposium in Padova, Italy.

Many scaling relationships have been proposed to link subaqueous sand dune dimensions with aspects of flow. This is useful for estimating dune dimensions from flow depth and velocity, which can be used to estimate dissipation of flow energy, bottom turbulence generation and bedload sediment transport.

However, when data is compiled from rivers worldwide, one observes a more than order of magnitude variation in dune height or length for a given flow depth. Why? We investigate using a very large data set collected from the Colorado River in Grand Canyon. We find that dune dimensions are controlled by grain size and degree flow constriction.

 
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October 2017. New sensors installed on the Chippewa River, WI, to measure "total load" 

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August 2017. Presented at the American Fisheries Society annual meeting in Tampa, Florida.

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April 2017. Channel Mapping in Western Grand Canyon

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March 2017. Article published in Environmental Modelling and Software

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