A new sampler for extracting bed material sediment from sand and gravel beds in navigable rivers

Numerous recent studies on fluvial processes, both in Canada and internationally, have focused on small-scale phenomena. Investigations on the characterization of surface roughness in coarse-grained channels and its links with flow resistance and sediment transport processes have been a dominant field of research. Closely related is a second major area of investigation on turbulent flow structures in boundary layers over both sand and gravel beds and their relations with the transport of bed material. Phenomena potentially related to 'bursting' have been shown to control bedload transport processes and the concentration of sediment in suspension. Detailed investigations have also been conducted on the links between flow turbulence, bed material movement, and bed morphology at channel junctions. Finally, selective entrainment and transport of individual coarse particles have been studied from field measurements and laboratory experi ments. Emphasis has been put on bed microtopography, surface structure and texture, and on a probabilistic approach to bedload transport.

Download Full-text

Organic detritus particles: Initiation of motion criteria on sand and gravel beds

Water Resources Research ◽

10.1029/wr019i006p01627 ◽

1983 ◽

Vol 19 (6) ◽

pp. 1627-1631 ◽

Cited By ~ 12

Author(s):

John S. Fisher ◽

Ben L. Sill ◽

Douglas F. Clark

Keyword(s):

Organic Detritus ◽

Gravel Beds ◽

Sand And Gravel

Download Full-text

Herbicide Losses in Runoff of Containerized Plant Production Nurseries

HortTechnology ◽

10.21273/horttech.13.1.0016 ◽

2003 ◽

Vol 13 (1) ◽

pp. 16-22 ◽

Cited By ~ 3

Author(s):

Melissa B. Riley

Keyword(s):

Weed Management ◽

Water Soluble ◽

Plant Production ◽

Herbicide Application ◽

Clemson University ◽

Continuous Irrigation ◽

Gravel Beds ◽

Herbicide Transport ◽

Bed Material ◽

Herbicide Use

Herbicide use in containerized plant production nurseries is a vital tool for weed management and the production of plants desired by the consumer. Clemson University researchers have conducted studies aimed at determining the amount of herbicide runoff during normal nursery operation, if herbicides accumulate in containment ponds at nurseries, and how herbicide runoff could be reduced. A 2-year study at commercial nurseries found that herbicide concentrations were higher in containment ponds soon after herbicide application, when compared with months with less herbicide application; and herbicides did not accumulate over the 2-year period. Herbicide runoff was greatest immediately after application and up to 15% of the herbicide applied was lost in the first irrigation event after application when using more water soluble herbicides. Bed material and herbicide formulation were also important in determining the amount of herbicide lost. Total losses were highest from plastic- and fabric-covered beds when using granular formulations and highest from gravel beds when spray formulations were used. The combination of using cyclic irrigation and grass waterways resulted in a reduction of about 25% of isoxaben loss when compared with clay and gravel waterways with continuous irrigation. The effects of reduced herbicide treatments compared to standard spray schedules were evaluated on herbicide transport, weed development, and plant growth and health. Results indicated that plant marketability was not affected, and total herbicide runoff was significantly reduced. Based on these studies, several recommendations can be made to commercial container plant production nurseries, which should reduce herbicide runoff and thereby reduce the environmental concerns associated with nurseries.

Download Full-text

Hydrogeomorphic effects on bedload scour in bull char (Salvelinus confluentus) spawning habitat, western Washington, USA

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f10-007 ◽

2010 ◽

Vol 67 (4) ◽

pp. 626-640 ◽

Cited By ~ 15

Author(s):

Jeffrey G. Shellberg ◽

Susan M. Bolton ◽

David R. Montgomery

Keyword(s):

Woody Debris ◽

Main Channel ◽

Spawning Habitat ◽

Stream Power ◽

Salvelinus Confluentus ◽

Channel Change ◽

Gravel Beds ◽

Side Channels ◽

Western Washington ◽

Sand And Gravel

We investigated the vulnerability of fall-spawned bull char ( Salvelinus confluentus ) embryos to redd scour during winter rain and rain-on-snow flood discharges in western Washington, USA. It was hypothesized that the magnitude of bedload scour at bull char redds is reduced by the provision and selection of stable refugia habitat controlled by local-, reach-, or subcatchment-scale variables such as hydraulic habitat unit and channel type. Bedload scour and channel change were measured using 96 scour monitors and 34 elevational transects in three catchments over 2 to 4 years. Scour to cited egg burial depths of bull char did not commence until discharge typically exceeded the 2-year recurrence interval. At a local scale, scour varied significantly among side channel, protected main channel, and unprotected main channel redd sites. Unprotected gravel patches in simplified channel types with moderate gradients were most susceptible to deep scour, especially if coupled with the transient supply and storage of sand and gravel from mass wasting. Partially transport-limited reaches had reduced scour due to lower stream power and armored gravel beds. Complex spawning habitat (i.e., with abundant large woody debris and side channels) was important in providing refuge from deep scour and in buffering embryos against inhospitable hydrologic or sediment regimes.

Download Full-text

Application of Geophysical Logging to Groundwater Studies in Southeastern Saskatchewan

Canadian Journal of Earth Sciences ◽

10.1139/e72-007 ◽

1972 ◽

Vol 9 (1) ◽

pp. 78-94 ◽

Cited By ~ 9

Author(s):

J. H. Dyck ◽

W. S. Keys ◽

W. A. Meneley

Keyword(s):

Epithermal Neutron ◽

Single Point ◽

Good Resolution ◽

Spontaneous Potential ◽

Gravel Beds ◽

Natural Gamma ◽

Water Well ◽

Resistivity Logs ◽

Routine Basis ◽

Sand And Gravel

Single-point resistance and spontaneous potential logs in fresh-water filled rotary-drilled test-holes provide data useful in geohydrologic studies in Saskatchewan. These geophysical logs are made by many of the water well drilling contractors in Saskatchewan on a routine basis. The logs provide good resolution of various lithologic units and provide data required to estimate the salinity of water in sand beds prior to constructing a well.Caliper logging offers a potentially useful method for evaluating hole conditions and the effect of drilling techniques on the formation in completion zones. The casing collar locator log run in a previously constructed well near Estevan demonstrates that this device can provide an accurate and objective measurement of the position and length of each joint of casing, the position of the screen assembly, and the location of screened and blanked intervals within the screen assembly. This tool should find general application in water well construction and maintenance practice.The neutron-epithermal neutron log provides a method of measuring the porosity of sand and gravel beds. The response of the gamma log is similar to that of the spontaneous potential log and the neutron-epithermal neutron log deflects in a fashion similar to the resistance and resistivity logs. Nuclear logs offer the advantage that they can be run in cased or uncased boreholes which may be filled with any type of fluid. They require more complicated and expensive instrumentation and slow-speed logging to obtain the required resolution. The normal resistivity logs offer the possibility of determining the concentration of dissolved solids in the formation water. The gamma-gamma log is a poor alternative to the natural gamma and neutron log for stratigraphic correlations.

Download Full-text