TY - JOUR
T1 - Avgwlf-based estimation of nonpoint source nitrogen loads generated within long island sound subwatersheds
AU - Georgas, Nickitas
AU - Rangarajan, Srinivasan
AU - Farley, Kevin J.
AU - Jagupilla, Sarath Chandra K.
PY - 2009/6
Y1 - 2009/6
N2 - The Generalized Watershed Loading Functions (GWLF) model and its ArcView interface (AVGWLF) were used to estimate and examine the components of the total nitrogen (TN) nonpoint source (NPS) load generated within New York and Connecticut (CT) watersheds surrounding Long Island Sound (LIS, the Sound). The majority of data used as model inputs were generally available from online sources, and the work involved an overall calibration to streamflow and TN data in accordance with generic guidelines recommended in the GWLF manual. The GWLF model performance for three calibration and two validation watersheds in CT was compared with results of a detailed model, Hydrological Simulation Program in Fortran, developed in a previous study. The results of the application illustrate the usefulness of the relatively simpler, less parameter-intensive GWLF model in performing exploratory loading analysis in preparation for adaptive nutrient management in the LIS watersheds. The presented methodology is valuable for identification of priority watersheds for NPS pollution reduction and also for planning-level evaluation of best management practices to achieve the desired reductions. It is estimated that ground-water base flow may be the largest pathway for NPS TN to the Sound, contributing about 54% of the total NPS TN load, a finding with significant implications for LIS total maximum daily load reduction scenarios. In addition to ground water, septic systems are estimated to contribute about 17% of the total load, with the remaining TN load being mostly runoff from urban (17%), agricultural (5%), and low impact (e.g., forest) areas (6%).
AB - The Generalized Watershed Loading Functions (GWLF) model and its ArcView interface (AVGWLF) were used to estimate and examine the components of the total nitrogen (TN) nonpoint source (NPS) load generated within New York and Connecticut (CT) watersheds surrounding Long Island Sound (LIS, the Sound). The majority of data used as model inputs were generally available from online sources, and the work involved an overall calibration to streamflow and TN data in accordance with generic guidelines recommended in the GWLF manual. The GWLF model performance for three calibration and two validation watersheds in CT was compared with results of a detailed model, Hydrological Simulation Program in Fortran, developed in a previous study. The results of the application illustrate the usefulness of the relatively simpler, less parameter-intensive GWLF model in performing exploratory loading analysis in preparation for adaptive nutrient management in the LIS watersheds. The presented methodology is valuable for identification of priority watersheds for NPS pollution reduction and also for planning-level evaluation of best management practices to achieve the desired reductions. It is estimated that ground-water base flow may be the largest pathway for NPS TN to the Sound, contributing about 54% of the total NPS TN load, a finding with significant implications for LIS total maximum daily load reduction scenarios. In addition to ground water, septic systems are estimated to contribute about 17% of the total load, with the remaining TN load being mostly runoff from urban (17%), agricultural (5%), and low impact (e.g., forest) areas (6%).
KW - ArcView generalized watershed loading functions
KW - Decision support systems
KW - Generalized watershed loading functions
KW - Long Island Sound
KW - Nitrogen
KW - Nonpoint source pollution
KW - Total maximum daily load
KW - Watershed modeling
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U2 - 10.1111/j.1752-1688.2009.00318.x
DO - 10.1111/j.1752-1688.2009.00318.x
M3 - Article
AN - SCOPUS:66149113194
SN - 1093-474X
VL - 45
SP - 715
EP - 733
JO - Journal of the American Water Resources Association
JF - Journal of the American Water Resources Association
IS - 3
ER -