نتایج جستجو برای: sediment removal

تعداد نتایج: 177490  

Journal: :international journal of advanced biological and biomedical research 2014
mohsen norouzi

hydro-induction sediment discharge technique (hsdt) aims to prevent reservoir sedimentation by withdrawing the discharge water from the reservoir bottom to suck up and discharge sediments, and by inducing vertical vortexes and undercurrents in the reservoir bay to keep sediments agitated and moving. the technique is facilitated with an innovative discharge conduit system having bottom intakes t...

2017
Hong Wang Tongzhou Liu Shuai Feng Weihua Zhang

In ex-situ washing, HCl, EDTA and H2O2 solutions can effectively extract heavy metals in river sediment. Nevertheless they often target different sediment components, possibly transforming metal species into more bioavailable and hence toxic ones. This study, in batch settings, investigated the influences of different types of washing agents (i.e. HCl, EDTA and H2O2) on metal (i.e. Cu and Zn) r...

2012
Daniel J. Nowacki Alexander R. Horner-Devine Jonathan D. Nash David A. Jay

We compute rates of sediment removal from the Columbia River, USA plume near field using a control volume technique. By using data from repeated transect passes along the plume axis, we account for variations in plume width, depth, and velocity, and we construct a framework for determining the dominant terms in the complete sediment balance. The contribution due to turbulent sediment flux is es...

2017
Stephen P Rubin Ian M Miller Melissa M Foley Helen D Berry Jeffrey J Duda Benjamin Hudson Nancy E Elder Matthew M Beirne Jonathan A Warrick Michael L McHenry Andrew W Stevens Emily F Eidam Andrea S Ogston Guy Gelfenbaum Rob Pedersen

The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx-over 10 million tonnes-during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal com...

2004
CHRISTOPHER T. SOLOMON ALEXANDER S. FLECKER BRAD W. TAYLOR

In Neotropical streams, benthic sediment affects community structure and may impose energetic costs for some species yet to be a resource for others. This study tested the hypothesis that removal of benthic sediment through ingestion by Rana palmipes (Ranidae), a detritivorous tadpole, facilitated the growth of Ancistrus triradiatus (Loricariidae), an algivorous armored catfish. We hypothesized...

Journal: :Environmental management 2007
Sheila J Roberts Johan F Gottgens Alison L Spongberg James E Evans Norman S Levine

This is a study of the scientific component of an effort to restore an urban river by removing a low-head dam. The Secor Dam is owned by a local government entity near Toledo, Ohio. The proposed removal of the last structure impeding flow on the Ottawa River has broad appeal, but the owner is concerned about liability issues, particularly potential changes to the flood regime, the presence of c...

2012
Lorelei J Alvarez Howard E Epstein Junran Li Gregory S Okin

Many arid grassland communities are changing from grass dominance to shrub dominance, but the mechanisms involved in this conversion process are not completely understood. Aeolian processes likely contribute to this conversion from grassland to shrubland. The purpose of this research is to provide information regarding how vegetation changes occur in an arid grassland as a result of aeolian sed...

Journal: :Chemosphere 2007
Christian Löser Andreas Zehnsdorf Petra Hoffmann Heinz Seidel

Remediation of heavy metal polluted sediment by extracting the metals with sulfuric acid can be performed as follows: abiotic suspension leaching, microbial suspension leaching, abiotic solid-bed leaching, and microbial solid-bed leaching. Abiotic leaching means that the acid is directly added, while microbial leaching means that the acid is generated from sulfur by microbes (bioleaching). Thes...

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