In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a commonly used assumption. However, not all natural gravel channels actually conform to this...

Early-stage Chinook salmon Oncorhynchus tshawytscha embryos were incubated in artificial redds that mimicked hyporheic conditions in gravel-augmented habitat to assess survivorship. Two complementary experiments were conducted where units varied along gradients of (1) increasing interstitial flow velocity (0·05-2·50 cm s⁻¹) in a uniformly coarse (particles ≥22 mm) sediment mixture and (2) incre...

Coarse-grained beaches are particularly prevalent in the UK, composed of accumulations of either gravel, or mixed sand and gravel sediments. Understanding and predicting their morphological behaviour in response to short-term and long-term forcing has been the subject of recent research. Despite the focus on sandy beaches, it is important to understand that the balance of processes that govern ...

—Endangered Interior Least Terns ( Sterna antillarum athalassos ) and threatened Piping Plovers ( Charadrius melodus ) nest in Nebraska at gravel mines where they are vulnerable to disturbance and nest loss. Conflicts occur when their nesting and protected status delay mining activities. The possibility of shifting nesting from active to inactive mining areas by using a deterrent (mylar flaggin...

In a recent issue of the Proceedings, Jennings & Smyth (1990) investigated a critical aspect of the Holocene coastal evolution of much of Britain; namely gravel (or shingle) sediment supply and beach morphodynamics through time. Their study area is the coastline of East Sussex, and it should be noted that it is only a component of the larger coastal unit (or 'master cell') between Selsey Bill a...

We use the Be concentration in alluvial sand and gravel to document hillslope exposure history and trace the reduction in grain size of river alluvium in the Clearwater River basin, western Washington State. Clearwater tributary basins Wilson Creek (WC, 6 km) and East Fork Miller Creek (EFMC, 12 km) were each sampled in headwater and downstream sites for Be in alluvial sand (0.25–0.50 mm) and g...

Two groups of 4 pigeons learned either matching-to-sample or oddity-from-sample by digging in white and black gravel for buried grain. Learning occurred as early as Trial 11, and acquisition was accelerated by as much as 100-fold compared with learning in traditional key-peck environments. Control experiments showed that performance was not controlled by cues other than the gravel stimuli and w...

Application of over-winter green cover (e.g. cover crops) as a measure for reducing nitrate losses from tillage land has been frequently investigated, especially in the unsaturated zone. Monitoring of groundwater is less common in these studies. Studies on groundwater responses to different land treatments can be challenging because they can be influenced by various conditions, such as recharge...

AND GRAVEL AQUIFER IN CAPE COD, MASSACHUSETTS USING A 3-D NUMERICAL MODEL by ALBERTO M. LAZARO B.S., Civil Engineering Cornell University, 1995 Submitted to the Department of Civil and Environmental Engineering In Partial Fulfillment of the Requirements for the Degree of MASTER OF ENGINEERING in Civil and Environmental Engineering at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 1996 © 1996 Ma...

SUMMARY This Report describes work undertaken in an attempt to establish the feasibility of using models to investigate the performance of gravel arresters for aircraft. The experiments were designed using the techniques of physical similarity and dimensional analysis, Tests were carried out with 1:9.3 scale models of Lightning and Canberra aircraft in two types of sand, and the results compare...