-We measured scour of the redds of chinook salmon Oncorhynchus tshawytscha on dredge tailings and natural substrates in three tributaries of the Klamath River, California. We measured maximum scour with scour chains and net scour by surveying before and after high winter flows. Scour of chinook salmon redds located on dredge tailings exceeded scour of redds on natural substrates, although the d...

Scour is by far the primary cause of bridge failures in the United States. Scour and other hydraulic effects are particularly threatening because the deterioration is often invisible , hidden beneath turbid water. Many scour monitoring methods attempt to measure the development of scour pockets themselves. However, this is difficult due to debris — both floating and submerged — and shifting str...

This study addresses the design of riprap aprons as a scour countermeasure near abutments under clear-water conditions. It deals with the lateral extent of riprap aprons and the geometry of the scour hole prevailing at the apron edge. The study applies to riprap aprons acting as granular filters. The scour depth appears to be independent for a sufficiently long relative abutment length. Scour h...

Series of laboratory tests were carried out to study the extent of scour caused by a three-dimensional wall jets exiting from a square cross-section nozzle and into a non-cohesive sand beds. Previous observations have indicated that the effect of the tail water depth was significant for densimetric Froude number greater than ten. However, the present results indicate that the cut off value coul...

One of the most concerning issues for researchers is to predict the shape and dimensions of the scour pit nearhydraulic structures such as the base of bridges, weirs, valves and stilling basins due to both financial and humanhazards induced by destruction of the structure. As the scour issue has its own complexity in relation to themultiplicity of effecting factors on it, in this study therefor...

Scour is the erosion of bed and bank material by flowing water; scour poses a threat to bridge security by undermining piers and abutments over time. In fact, “the most common cause of bridge failures is floods with the scouring of bridge foundations being the most common cause of flood damage” (Richardson et al., 1993). While regular inspections and maintenance reduce the risk of a scourrelate...

Current formulas for calculating scour depth below of a free over fall are mostly deterministic in nature and do not adequately consider the uncertainties of various scouring parameters. A reliability-based assessment of scour, taking into account uncertainties of parameters and coefficients involved, should be performed. This paper studies the reliability of a dam foundation under the threat o...

Prediction of the scour around a group of pile in the field exposed to oscillatory waves is very important for many offshore structure and coastal engineering projects. Conventional predictive formulas for the geometric properties of scour hole, however, are not able to provide sufficiently accurate results. In this paper the ANNs approach is used to predict the scour depth around pile group us...