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Sensitivity Analysis and Model Evaluation of Bifenthrin Surface Water Concentrations from California Urban Runoff
Citation:
Chelsvig, E., F. Ayivi, Y. Luo, D. Denton, A. Pitchford, Sandy Raimondo, D. Ebert, Tom Purucker, AND Y. Yuan. Sensitivity Analysis and Model Evaluation of Bifenthrin Surface Water Concentrations from California Urban Runoff. 10th International Congress on Environmental Modelling and Software Conference 2020, Brussels, N/A, BELGIUM, July 06 - 10, 2020. https://doi.org/10.23645/epacomptox.15046221
Impact/Purpose:
This abstract will be presented at the 10th International Congress on Environmental Modelling and Software Conference 2020. The abstract discusses the impact of urban runoff on aquatic species in the Sacramento-San Joaquin Delta.
Description:
Aquatic species in the Sacramento-San Joaquin Delta are impacted by urban runoff. Bifenthrin is a major component of pyrethroid runoff to the Delta, particularly after storm events. It is used by pest control applicators for landscape application or as a perimeter treatment to quell pests from entering urban structures. This study employs deterministic and probabilistic approaches with the US EPA’s Pesticide Water Calculator (PWC version 1.59) to simulate bifenthrin concentration in runoff from 4 urban storm drains located in Placer and Sacramento County in order to assess urban contributions to surface water concentrations. The deterministic approach used conservative (high) estimates for model inputs to calculate concentrations. The probabilistic approach used Latin Hypercube Sampling technique to sample inputs from predefined ranges to propagate variability through the model. A global sensitivity analysis was then administered to identify sensitive inputs with respect to model output variability. Partial correlation coefficients were used to measure input sensitivity. This analysis identifies inputs whose variation substantially contributes to output variability and uncertainty. This provides the necessary information to prioritize efforts for uncertainty reduction by focusing on highly sensitive inputs, in addition to providing insight into model input-output relationships. Sensitivity results are driven by curve number and universal soil loss parameters. Sensitivity dynamics are explored daily to demonstrate changes in sensitivity associated with major storm events. Predictions are compared to a five-year period of measured data to evaluate the performance of the PWC model for predicting downstream concentrations in urban environments.
URLs/Downloads:
DOI: Sensitivity Analysis and Model Evaluation of Bifenthrin Surface Water Concentrations from California Urban Runoff
CHELSVIG_IEMSS_POSTER3.PDF (PDF, NA pp, 1533.744 KB, about PDF)