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Evaluation of hydrology in an agricu...

North Carolina State University.

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Evaluation of hydrology in an agricultural watershed and nitrogen removal by constructed wetlands.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Evaluation of hydrology in an agricultural watershed and nitrogen removal by constructed wetlands./
作者:	Kim, Hyun Woo.
面頁冊數:	201 p.
附註:	Advisers: Stephen W. Broome; Devendra M. Amatya.
Contained By:	Dissertation Abstracts International70-05B.
標題:	Agriculture, Soil Science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3357735
ISBN:	9781109161144

Evaluation of hydrology in an agricultural watershed and nitrogen removal by constructed wetlands.
Kim, Hyun Woo.

Evaluation of hydrology in an agricultural watershed and nitrogen removal by constructed wetlands. - 201 p.

Advisers: Stephen W. Broome; Devendra M. Amatya.

Thesis (Ph.D.)--North Carolina State University, 2009.

Excessive nitrogen loading has been considered a major cause of water quality problems in eastern North Carolina. There has been a particular concern in coastal watersheds because agricultural and forested lands are located adjacent to recreational and environmentally sensitive waters. The key to nutrient management at the watershed scale is the understanding and quantification of the fate of nutrients at the field scale and after nutrients enter the aquatic environment. The constructed wetland, located at the outlet of a watershed, is recognized as an efficient and environmentally safe wastewater treatment system. There is no accepted method to describe and predict nitrogen transformation in canals and streams. Many studies have focused on the efficiency of constructed wetland systems for wastewater treatment, but the results still vary. The objectives of this research were to investigate the effects of in-stream processes in agricultural watersheds of the lower coastal plain, to determine nitrogen transformations in constructed wetlands, and to propose a modeling approach for quantifying nitrogen transport and in agricultural watersheds and constructed wetlands.

ISBN: 9781109161144Subjects--Topical Terms:

1017824
Agriculture, Soil Science.

Evaluation of hydrology in an agricultural watershed and nitrogen removal by constructed wetlands.
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100 1 $a Kim, Hyun Woo. $3 1030314
245 1 0 $a Evaluation of hydrology in an agricultural watershed and nitrogen removal by constructed wetlands.
300 $a 201 p.
500 $a Advisers: Stephen W. Broome; Devendra M. Amatya.
500 $a Source: Dissertation Abstracts International, Volume: 70-05, Section: B, page: .
502 $a Thesis (Ph.D.)--North Carolina State University, 2009.
520 $a Excessive nitrogen loading has been considered a major cause of water quality problems in eastern North Carolina. There has been a particular concern in coastal watersheds because agricultural and forested lands are located adjacent to recreational and environmentally sensitive waters. The key to nutrient management at the watershed scale is the understanding and quantification of the fate of nutrients at the field scale and after nutrients enter the aquatic environment. The constructed wetland, located at the outlet of a watershed, is recognized as an efficient and environmentally safe wastewater treatment system. There is no accepted method to describe and predict nitrogen transformation in canals and streams. Many studies have focused on the efficiency of constructed wetland systems for wastewater treatment, but the results still vary. The objectives of this research were to investigate the effects of in-stream processes in agricultural watersheds of the lower coastal plain, to determine nitrogen transformations in constructed wetlands, and to propose a modeling approach for quantifying nitrogen transport and in agricultural watersheds and constructed wetlands.
520 $a The first step was a review of the literature on nitrogen retention in agricultural streams, nitrogen transformation in constructed wetlands, and design criteria of constructed wetlands for efficient nitrogen removal. In the second step, the daily outflow from a 1037 ha agricultural watershed at Open Grounds Farm was evaluated using the DRAINWAT, DRAINMOD for Watershed, in the lower Coastal Plain, Carteret County, North Carolina. As a third step, vegetation succession and efficiency of nitrogen removal was monitored, and a sequential model of nitrogen transformations in wetlands was evaluated.
520 $a In order to estimate nitrogen loading from the agricultural watershed, accurate simulation results of hydrology are required. However, the watershed was not intensively instrumented for hydrologic simulation at the period of our study. Mainly due to problems with flow meters and lack of sufficient measured data, the hydrology simulation results were not adequate to estimate nitrogen loading. For this reason, nitrogen loading was introduced only in the methodology section, and this study focused on the sensitivity analysis using four input parameters: Manning's roughness coefficient, maximum depressional storage, calculation methods of potential evapotranspiration (PET), and channel bedslope. PET calculation methods were found to be most sensitive among those four parameters. Two Thornthwaite based methods using different correction factors (Thorn 1 and Thorn 2) were tested. Thorn 2 correction factors obtained from the agricultural watershed were more accurate than Thorn 1 correction factors, which were averaged from two agricultural and one forested watershed.
520 $a Vegetation succession in the wetland cells and nitrogen removal efficiency of constructed wetland system were monitored in chapter 3. Three hydrophyte species including Juncus roemerianus, Cladium jamaicense, and Spartina alterniflora were successfully established in the constructed wetland, but the growth rate of J. roemerianus and C. jamaicense was significantly faster than that of S. alterniflora in this new environmental condition. Good removal efficiencies of constructed wetland system for all nitrogen species were observed. A simple, sequential model of nitrogen transformation model was tested at the inlet of constructed wetlands using limited measured flow data in selected periods. Simulation results were not yet reasonable due to the limited number of sample data, a long waterway before the first cell of the constructed wetland, and non-calibrated average rate constant of the model. This model may predict the concentration of nitrogen species successfully with proper calibration with more measured data.
590 $a School code: 0155.
650 4 $a Agriculture, Soil Science. $3 1017824
650 4 $a Biogeochemistry. $3 545717
650 4 $a Engineering, Agricultural. $3 1019504
650 4 $a Hydrology. $3 545716
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710 2 $a North Carolina State University. $3 1018772
773 0 $t Dissertation Abstracts International $g 70-05B.
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790 1 0 $a Amatya, Devendra M., $e advisor
790 1 0 $a Broome, Stephen W., $e advisor
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3357735