نتایج جستجو برای: sediment

تعداد نتایج: 36882  

2007
Xiaobo Chao Yafei Jia F. Douglas Shields Charles M. Cooper

Sediment is a major nonpoint-source pollutant, and the exchange of materials between water and sediment is an important component of the lake eutrophication process. Suspended sediment increases water surface reflectivity and light attenuation in the water column. Nutrients can be absorbed to sediment particles and desorb from sediment to the water. In addition, nutrients can also be released f...

2006
M. H. Nichols

Data describing long-term sediment yield rates on semiarid rangeland watersheds are relatively rare. To augment existing data and gain a better understanding of the controlling variables, sediment yields from 8 subwatersheds within the US Department of Agriculture–Agricultural Research Service Walnut Gulch Experimental Watershed in southeastern Arizona were computed from stock pond sediment acc...

Journal: :Environmental science and pollution research international 2007
Almut Gerhardt

GOAL, SCOPE AND BACKGROUND Lumbriculus variegatus Miller (Oligochaeta), a common freshwater sediment-dweller, has frequently been used in toxicokinetic studies, although has been less used in ecotoxicity tests. METHODS For the first time the Multispecies Freshwater Biomonitor (MFB) was applied in a short-term whole-sediment toxicity test. The MFB automatically and quantitatively recorded the ...

Journal: :نشریه علمی - پژوهشی هیدرولوژی کاربردی 0
fatemeh shokrian sari agricultural sciences and natural resources university k. shahedi

estimate of sediment load is required in a wide spectrum of water resources engineering problems. the nonlinear nature of suspended sediment load series necessitates the utilization of nonlinear methods to simulate the suspended sediment load. in this study artificial neural networks (anns) are employed to estimate daily suspended sediment load. two different ann algorithms, multi layer percept...

2010
Guang C. Chen Yong Ye

Sesarmid crabs are important ecosystem engineers in mangroves because they remove a large proportion of mangrove leaf litter. However, the effects on mangrove sediments of sesarmid crab foraging on mangrove leaves has been poorly quantified. Through a laboratory experiment, the present study aimed to quantify changes in nutrient concentrations and enzyme activities in mangrove sediment due to f...

2014
Eleni Yeshaneh Alexander Eder Günter Blöschl

Cop Abstract: Event sediment transport and yield were studied for 45 events in the upstream part of the 260 km agricultural Koga catchment that drains to an irrigation reservoir. Discharge and turbidity data were collected over a period of more than a year, accompanied by grab sampling. Turbidity was very well correlated with the sediment concentrations from the samples (r = 0.99), which allowe...

2007
Carlos E. Ramos-Scharrón Lee H. MacDonald

A quantitative understanding of both natural and anthropogenic sediment sources is needed to accurately assess and predict the potentially adverse effects of land development on aquatic ecosystems. The main objective of this study was to quantify sediment production and delivery rates in a dry tropical environment on the island of St. John in the eastern Caribbean. One to three years of measure...

ژورنال: علوم آب و خاک 2012
حسن احمدی, , فرود شریفی, , کاظم نصرتی, ,

Sediment sources fingerprinting is needed as an autonomous tool for erosion prediction, validation of soil erosion models, monitoring of sediment budget and consequently for selecting soil conservation practices and sediment control methods at the catchment scale. Apportioning of eroded-soil into multiple sources using natural tracers is an integrated approach in soil erosion and sediment studi...

This study was aimed at identification and determination the spatial variations of sediment yield in Qarasu watershed located in Ardebil province, NW Iran, considering the negative consequences of erosion and sediment yield. In this regard, the monthly time scale, as the basis of work, was used to prepare the sediment rating curves. Preparation of monthly sediment rating curves based on sample ...

2006
Momcilo Markus

Water resources managers always are searching for cost-effective monitoring programs that provide maximum information for minimum cost. Monitoring of sediment discharges from streams and rivers is one of the expensive efforts that is always reduced or cut when financial resources are limited. This has resulted in a very limited number of long-term sediment monitoring sites in the United States....

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