نتایج جستجو برای: sediment threshold

تعداد نتایج: 158501  

A.R. Sepaskhah H. Parvizi

ABSTRACT- In recent years, intensive drought has caused a severe yield reduction in rain-fed trees. Increasing runoff of low amount rainfall can be used to provide partial water requirement of rain-fed trees. To achieve this objective, some strategies including gravel removal (G), rill construction across to slope (R) and applying of baking soda (S) and their effects on runoff, rainfall infiltr...

2004
Leonard S. Sklar William E. Dietrich

[1] Abrasion by bed load is a ubiquitous and sometimes dominant erosional mechanism for fluvial incision into bedrock. Here we develop a model for bedrock abrasion by saltating bed load wherein the wear rate depends linearly on the flux of impact kinetic energy normal to the bed and on the fraction of the bed that is not armored by transient deposits of alluvium. We assume that the extent of al...

2010
Philip E. Higuera Daniel G. Gavin Patrick J. Bartlein Douglas J. Hallett

Over the past several decades, high-resolution sediment–charcoal records have been increasingly used to reconstruct local fire history. Data analysis methods usually involve a decomposition that detrends a charcoal series and then applies a threshold value to isolate individual peaks, which are interpreted as fire episodes. Despite the proliferation of these studies, methods have evolved largel...

Journal: :Journal of environmental quality 2016
Carl F Cerco

The Conowingo Reservoir is situated on the Susquehanna River, immediately upstream of Chesapeake Bay, the largest estuary in the United States. Sedimentation in the reservoir provides an unintended benefit to the bay by preventing sediments, organic matter, and nutrients from entering the bay. The sediment storage capacity of the reservoir is nearly exhausted, however, and the resulting increas...

Journal: :Environmental science & technology 2012
Juan José Alava Peter S Ross Cara Lachmuth John K B Ford Brendan E Hickie Frank A P C Gobas

The development of an area-based polychlorinated biphenyl (PCB) food-web bioaccumulation model enabled a critical evaluation of the efficacy of sediment quality criteria and prey tissue residue guidelines in protecting fish-eating resident killer whales of British Columbia and adjacent waters. Model-predicted and observed PCB concentrations in resident killer whales and Chinook salmon were in g...

Journal: :Applied and environmental microbiology 1997
F E Loffler J E Champine K M Ritalahti S J Sprague J M Tiedje

The transformation of 1,2-dichloropropane (1,2-D) was observed in anaerobic microcosms and enrichment cultures derived from Red Cedar Creek sediment. 1-Chloropropane (1-CP) and 2-CP were detected after an incubation period of 4 weeks. After 4 months the initial amount of 1,2-D was stoichiometrically converted to propene, which was not further transformed. Dechlorination of 1,2-D was not inhibit...

2017
Haiyun Shi Chao Gao Changming Dong Changshui Xia Guanglai Xu

River islands are sandbars formed by scouring and silting. Their evolution is affected by several factors, among which are runoff and sediment discharge. The spatial-temporal evolution of seven river islands in the Nanjing Section of the Yangtze River of China was examined using TM (Thematic Mapper) and ETM (Enhanced Thematic Mapper)+ images from 1985 to 2015 at five year intervals. The followi...

2009
Rodolfo Bolanos Benjamin D. Moate Alejandro Souza

Coastal areas support many human activities and represent a very important habitat for many marine and bird species. The Dee estuary, located in the eastern Irish Sea, is 20 km long, 8 km wide at the mouth and is characterized by a 10 m tidal range. Suspended and seabed sediments in the Dee contain a diverse assemblage of non-cohesive and cohesive sediments, and therefore the threshold of motio...

Journal: :Journal of environmental quality 2017
Raea M Gooding Helen M Baulch

There are few beneficial management practices (BMPs) with demonstrated efficacy in snowmelt-dominated regions. Small reservoirs are a BMP that can help mitigate flooding and reduce sediment transport, while reducing export of dissolved nutrients. To understand controls on nitrate removal and assess how this ecosystem service can be optimized, denitrification activity was measured in reservoirs ...

2007
Cyndee Gruden Richard McCulloch Tim Towey John Wolfe Peter Adriaens

The potential for hydrogen gas to stimulate microbial respiratory activity in sediments was investigated. Cell elutions from Passaic River (NJ), San Diego Bay (CA), and Marine Harbor sediments were amended with hydrogen gas to evaluate its impact on microbial activity measured by intracellular reduction of 5cyano-2,3-ditolyl tetrazolium chloride (CTC). The transferability of this approach to se...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید