Assessing the Relative Importance of Nitrogen-Retention Processes in a Large Reservoir Using Time-Series Modeling

作者：Hansen Elizabeth; Chan Kung Sik^*; Jones Christopher S; Schilling Keith

来源：Journal of Agricultural, Biological, and Environmental Statistics, 2016, 21(1): 152-169.

DOI：10.1007/s13253-015-0218-1

• Nitrate-nitrogen
• Reservoirs
• Time-series modeling
• Denitrification
• Assimilation

Nitrogen (N) removal within reservoirs can be substantial, but few studies have reported the relative importance of various N-retention pathways. Assessing N-removal processes in reservoirs is important for quantifying the impacts of reservoirs on downstream water quality. In this study, we used a time-series approach to quantify the relative importance of various N-removal processes in the Saylorville Reservoir in Iowa. Dynamic regression modeling of upstream-downstream changes in key water-quality surrogates (pH, hardness, alkalinity, and suspended solids) and their relation to N concentration changes were used to estimate the relative importances of denitrification, N assimilation by algal uptake, and sedimentation of N on N retention in the reservoir. Assuming that decreasing N concentrations in the reservoir are the sum of these three processes, we estimate that denitrification is the dominant N removal process (60.9 %) followed by algal assimilation (37.9 %) and sedimentation (1.2 %). Our approach represents a new method of establishing the relative importance of N-removal processes in reservoirs and quantifying the impacts of reservoirs on downstream water quality.
Supplementary materials accompanying this paper appear on-line.

• 出版日期2016-3