نتایج جستجو برای: bed sediments

تعداد نتایج: 77010  

2009
Elizabeth J. Palmer-Felgate Helen P. Jarvie Paul J.A. Withers Robert J.G. Mortimer Michael D. Krom

Stream-bed sediments from three paired catchments, each draining a lower agricultural intensity system and a higher agricultural intensity system, were analysed for (a) total P (TP), (b) bioavailable-P (Resin-P), (c) equilibrium phosphorus concentration (EPC0), and (d) degree of phosphorus saturation (DPS). The influence of agriculture on sediment P was explored within the context of other key ...

2000
Thomas P. Quinn N. Phil Peterson

Analysis of frozen cores of chum salmon egg pockets collected in the fall revealed that spawning activity purged about 75% of the fine sediments Corn the stream bed. The egg pocket was one of four distinct vertical strata detected in the cores. There was an undisturbed layer below the egg pocket and cover and bridge strata above the egg pocket, defined by their particle size distributions. Howe...

2001
D. ANDRUS V. E. McKelvey

The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by the Water Resources Division for analysis of fluvial sediments to determine the concentration of suspendedsediment samples and the particle-size distribution of both suspended-sediment and bed...

2008
V.V.S. Gurunadha Rao C. K. Jain B. A. Prakash Mahesh Kumar

Hussainsagar lake in the heart of Hyderabad city receives domestic sewage and industrial effluents through five streams draining the catchment area of 245 sq. km around the lake. Lake used to receive untreated industrial effluents through streams during 1970 -1990. Over the years, sediments in the lake have adsorbed the heavy metals and have reported elevated concentrations. Metal speciation of...

Journal: :Journal of environmental monitoring : JEM 2012
Lijia Yang Xiqing Li Pengfei Zhang Michael E Melcer Youxian Wu Urs Jans

The concentrations of three frequently detected organochlorine pesticides (OCPs) and one degradation product, p,p'-DDT, p,p'-DDD, dieldrin, and p,p'-DDE were determined in recently collected (2005-2006) and archived (1986-1989) surficial sediments and sediment cores from Long Island Sound (LIS). The concentration of dieldrin ranged from 0.05 to 5.27 ng g(-1) dry weight in the surficial sediment...

Journal: :آب و خاک 0
سید علی موسوی ابراهیم امیری تکلدانی محمدهادی داودی

abstract rockfill dams are a type of hydraulic control structures used to protect river bed in cases where a considerable reservoir volume is available behind these structures; it could mitigate the floods and provide a gradual depletion of incoming volume of water so that the discharge passing downstream is decreased. one of the main issues on utilizing rockfill dams is to keep its permeabilit...

2014
Lin Cai Ming-Fei Shao Tong Zhang

Here, we report a type strain AST-10 representing a novel species Sulfurimonas hongkongensis within Epsilonproteobacteria, which is involved in marine sedimentary sulfur oxidation and denitrification. Strain AST-10(T) (= DSM 22096(T) = JCM 18418(T)) was isolated from the coastal sediment at the Kai Tak Approach Channel connected to Victoria Harbour in Hong Kong. It grew chemolithoautotrophicall...

2014
S. Guillén

River widening is commonly used as a solution for the rehabilitation of rivers with the main purposes of allowing the river to adjust to its natural dynamics and to improve riparian and instream habitat for flora and fauna, by increasing the heterogeneity in substrate, flow and morphology. Local widening may also be used for confluences rehabilitation as, for many of them, the heterogeneity and...

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