In this paper, we present the development of an in-air acoustic test-bed for rapid proof-of-concept testing of (underwater) communication technologies. In addition to more accurately representing the actual channel when compared to simulation, the test-bed also provides an easy method to introduce channel impairments, such as Doppler distortion, in a controlled manner. This can be advantageous ...

At Aberdaron, north Wales, a complex sequence of homogeneous tills and fluvial sediments overlie a hard rock base. The lower diamicton association at the bottom of the sequence consists of deformed tills and lenses of stratified sediments. It is suggested that these represent deforming bed tills and subglacial fluvial units which have been deformed together by subglacial excavational deformatio...

Large floods in northwestern California in the past two decades have mobilized extensive areas of valley floors, removed streamside trees, and widened channels. Channel cross sections were surveyed to illustrate an hypothesis on the linkage between sediment transport, colonization of channel margins by trees, and streambank recovery. Riparian trees, e.g., white alder (Alnus rhombifolia) , colon...

Entrainment of underlying debris by geophysical flows can significantly increase the flow deposit extent. To study this phenomenon, analog laboratory experiments have been conducted on granular column collapse over an inclined channel with and without an erodible bed made of similar granular material. Results show that for slope angles below a critical value θc, between 10◦ and 16◦, the run out...

[1] The present study examines variations in the reference shear stress for bed load transport (tr) using coupled measurements of flow and bed load transport in 45 gravel-bed streams and rivers. The study streams encompass a wide range in bank-full discharge (1–2600 m/s), average channel gradient (0.0003–0.05), and median surface grain size (0.027–0.21 m). A bed load transport relation was form...

The fluctuating bed shear stress has largely been investigated only for the conditions of uniform channel flows and boundary layers. In practical engineering, the flow conditions are often modified due to the presence of various hydraulic structures. To what extent the modification affects the known characteristics of the bed shear stress is not clear. This study presents experimental results o...

[1] A variety of formulae has been developed to predict bed load transport in gravel bed rivers, ranging from simple regressions to complex multiparameter formulations. The ability to test these formulae across numerous field sites has, until recently, been hampered by a paucity of bed load transport data for gravel bed rivers. We use 2104 bed load transport observations in 24 gravel bed rivers...

Spatially and temporally continuous temperature measurements were collected over 32 h using a fiber-optic distributed temperature sensing (DTS) system deployed along 330 m of two intertidal saltmarsh channel beds in northern California. Measured temperature gradients imparted ecosystem-scale structure to the saltmarsh tidal channel thermal regime, which was punctuated by potential warm and cold...