subject:(sediment re suspension)

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NSYSU

1. Wu, Chen-I. Using multi-frequency acoustic instruments to investigate the suspended sediment grain size and concentration characteristic in flume experiment and in the field.

Degree: Master, Marine Geology and chemistry, 2012, NSYSU

URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0726112-142244

In the past, the suspended sediment concentration (SSC) was mainly measured by the optical backscattering device (OBS) and water sample filtration. However, there has been a new development that user is based on the acoustics backscattering (ABS) to measure the SSC in the world. The acoustic instruments have some advantages that the optical ones do not have. For example, acoustic instruments are not effected by high turbidity, biofouling and high viscosity in the water. Acoustic instruments have high spatial and temporal resolutions. And they can immediately indicate the SSC changes than the water sample filtration method. Therefore, in this study we used the multi-frequency acoustics instrument (AQUAscat-1000) to investigate the relations of the suspended sediment size and concentration to the acoustic characteristics. The results are separated into two parts: (1) The calibration process in the flume. (2) The acoustic results in the field experiment. In the first part, we examined the range of preferred bin size with respect to the different frequencies as well as the condition in the flume, and determine that conclude the 20 mm is the best range for our case. In addition, the gain should be used when the maximum SSC is less than 100 mg/l and vice versa. Therefore, in the field case around the river mouth, the signal gain should be turned off due to high concentrations. According to the sensitivity of the backscatter intensity of different frequencies to the suspended particle sizes, multiple frequencies are needed to derive the SSC when the sediment size becomes smaller. The last point in this part is the comparison of the results between the acoustics and optical instruments. When the suspended particles in the water column are transparent, the optical measurement of the SSC is underestimated, but the acoustic method is not. The result of the field experiment in 2009 showed that the AQUAscat-1000 is a better instrument to quantify SSC than the optical instruments. The SSC increase caused by the bottom sediment re-suspension was due to the wave shear. In the 2011 experiment, although the acoustic results overestimated the SSC at some points but they still had higher relation and significance with water sample data than the optical measurements. The SSC increase caused by the bottom sediment re-suspension was due to the current shear. Advisors/Committee Members: Linus Y.S Chiu (chair), James T. Liu (committee member), Yu-Huai Wang (chair), Ruey-Chang Wei (chair).

Subjects/Keywords: flume; suspended sediment; multi-frequency acoustics; optical measurement; sediment re-suspension

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APA (6^th Edition):

Wu, C. (2012). Using multi-frequency acoustic instruments to investigate the suspended sediment grain size and concentration characteristic in flume experiment and in the field. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0726112-142244

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Wu, Chen-I. “Using multi-frequency acoustic instruments to investigate the suspended sediment grain size and concentration characteristic in flume experiment and in the field.” 2012. Thesis, NSYSU. Accessed March 07, 2021. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0726112-142244.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Vancouver:

Wu C. Using multi-frequency acoustic instruments to investigate the suspended sediment grain size and concentration characteristic in flume experiment and in the field. [Internet] [Thesis]. NSYSU; 2012. [cited 2021 Mar 07]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0726112-142244.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wu C. Using multi-frequency acoustic instruments to investigate the suspended sediment grain size and concentration characteristic in flume experiment and in the field. [Thesis]. NSYSU; 2012. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0726112-142244

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Virginia Commonwealth University

2. Sobotka, Molly. Legacy sediments in streams - effects on nutrient partitioning during simulated re-suspension events.

Degree: MS, Biology, 2011, Virginia Commonwealth University

URL: https://doi.org/10.25772/G954-NB30 ; https://scholarscompass.vcu.edu/etd/2564

Anthropogenic inputs of nutrients and sediment are a widespread problem in U.S. streams causing localized impairment and contributing to eutrophication of coastal habitats. Sediments and dissolved nutrients interact through diverse processes including ion exchange, sorption and biotic assimilation by particle-bound bacteria. This study examined the effects of sediment re-suspension on nutrient partitioning in lab microcosms using fine benthic matter collected from two Virginia Coastal Plain streams. Kimages Creek was recently restored following dam removal and was characterized by large deposits of legacy sediments. Courthouse Creek was characterized by sandy substrates typical of Coastal Plain streams. Sediment characteristics differed between the two sites and were influenced by discharge. Net nutrient release rates were similar between streams though reactivity of Courthouse Creek sediments was greater than that of Kimages Creek. Equilibrium Phosphate Concentrations calculated for each site show that fine sediments at Kimages Creek have resulted in higher phosphorus retention potential. Advisors/Committee Members: Paul Bukaveckas.

Subjects/Keywords: Coastal Plains stream; nutrient; re-suspension; nitrogen; phosphorus; sediment; Biology; Life Sciences

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sobotka, M. (2011). Legacy sediments in streams - effects on nutrient partitioning during simulated re-suspension events. (Thesis). Virginia Commonwealth University. Retrieved from https://doi.org/10.25772/G954-NB30 ; https://scholarscompass.vcu.edu/etd/2564

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sobotka, Molly. “Legacy sediments in streams - effects on nutrient partitioning during simulated re-suspension events.” 2011. Thesis, Virginia Commonwealth University. Accessed March 07, 2021. https://doi.org/10.25772/G954-NB30 ; https://scholarscompass.vcu.edu/etd/2564.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sobotka, Molly. “Legacy sediments in streams - effects on nutrient partitioning during simulated re-suspension events.” 2011. Web. 07 Mar 2021.

Vancouver:

Sobotka M. Legacy sediments in streams - effects on nutrient partitioning during simulated re-suspension events. [Internet] [Thesis]. Virginia Commonwealth University; 2011. [cited 2021 Mar 07]. Available from: https://doi.org/10.25772/G954-NB30 ; https://scholarscompass.vcu.edu/etd/2564.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sobotka M. Legacy sediments in streams - effects on nutrient partitioning during simulated re-suspension events. [Thesis]. Virginia Commonwealth University; 2011. Available from: https://doi.org/10.25772/G954-NB30 ; https://scholarscompass.vcu.edu/etd/2564

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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