نتایج جستجو برای: stream sediment

تعداد نتایج: 93248  

1999
Sun

Century-long studies on the impacts of forest management in North America suggest sediment can cause major reduction on stream water quality. Soil erosion patterns in forest watersheds are patchy and heterogeneous. Therefore, patterns of soil erosion are difficult to model and predict. The objective of this study is to develop a user-friendly management tool for land managers to design forest m...

2004
Tom J. Battin

I applied the fluorescein diacetate (FDA) hydrolysis technique as a rapid and sensitive estimator of total esterase activity in stream sediment biofilms. I investigated the effects of temperature, pH and incubation time and optimized the assay for low blanks and high fluorescein extraction. The FDA procedure was precise (c.v. = 4.15%) and could detect 10 nM fluorescein. Spatial patterns of este...

2001
David L. Rosgen

Various definitions of stream channel stability are presented including "the natural stable channel", the graded river, dynamic equilibrium, and regime channels, and a quantitative assessment methodology is presented that distinguishes between stability states. The assessment procedure involves a stream channel stability prediction and validation methodology on a hierarchical framework. The str...

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...

2014
Robert L. Stewart Cindy K. Harnett

A light attenuation sensor system (LASS) for measurements in waters is described in this paper. The LASS records irradiance at multiple levels in the water column to provide a measure of the diffuse light attenuation coefficient which is strongly affected by suspended sediment. Dimensional analysis and geometric optical theory are used to relate the irradiance attenuation to sediment properties...

2009
Jaepil Cho Saied Mostaghimi

* Corresponding author. E-mail addresses: [email protected] (J. Cho), sm 1537-5110/$ – see front matter Published by doi:10.1016/j.biosystemseng.2009.01.012 The dynamic agricultural non-point source assessment tool (DANSAT) is a distributedparameter, physically based, and continuous-simulation model for simulating spatial and temporal impacts of best management practices (BMPs) on hydrology and water...

2002
Melvin R. George Neil K. McDougald Kenneth W. Tate Royce Larsen

From 1994 to 1998 we documented sediment transport dynamics and sources in a 137 ha grazed hardwood rangeland watershed on granitic soils at the San Joaquin Experimental Range in Madera County. Sediment transport for this watershed was determined by measuring total suspended solids, bedload and flow at an H-flume installed in 1994. Sediment movement as bedload is the primary means of sediment t...

2013
Mon-Shieh Yang Ming-Chee Wu Jin-King Liu

The stream morphology may present different stages of fluvial processes by characteristics and sediments of various stream flow conditions; it played an important role for the stream cumulative stress. The stream morphology is being adjusted by the incoming stream flows as well as the sediments been carried. In Taiwan, streams are showing a very complicate topography due to the high eroding cap...

2016
Matteo Spagnolo Emrys Phillips Jan A. Piotrowski Brice R. Rea Chris D. Clark Chris R. Stokes Simon J. Carr Jeremy C. Ely Adriano Ribolini Wojciech Wysota Izabela Szuman

Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study...

Journal: :Environmental monitoring and assessment 2010
Christian F Lenhart Kenneth N Brooks Daniel Heneley Joseph A Magner

The Minnesota River Basin (MRB), situated in the prairie pothole region of the Upper Midwest, contributes excessive sediment and nutrient loads to the Upper Mississippi River. Over 330 stream channels in the MRB are listed as impaired by the Minnesota Pollution Control Agency, with turbidity levels exceeding water quality standards in much of the basin. Addressing turbidity impairment requires ...

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