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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #348750
Title: The importance of temporal inequality in quantifying vegetated filter strip removal efficiencies

Author
item GALL, HEATHER - Pennsylvania State University
item SCHULTZ, DANIEL - Pennsylvania State University
item Veith, Tameria - Tamie
item Goslee, Sarah
item MEJIA, ALFONSO - Pennsylvania State University
item HARMAN, CIARAN - Johns Hopkins University
item CIBIN, RAJ - Pennsylvania State University
item PATTERSON, PAUL - Pennsylvania State University

Submitted to: American Geophysical Union
Publication Type: Proceedings
Publication Acceptance Date: 12/13/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: No interpretive summary is required for this proceedings. JLB.

Technical Abstract: Vegetated filter strips (VFSs) are best management practices (BMPs) commonly implemented adjacent to row-cropped fields to trap overland transport of sediment and other constituents often present in agricultural runoff. VFSs are generally reported to have high sediment removal efficiencies (i.e., 70 – 95%); however, these values are typically calculated as an average of removal efficiencies observed or simulated for individual events. We argue that due to: (i) positively correlated sediment concentration-discharge relationships; (ii) strong temporal inequality exhibited by sediment transport; and (iii) decreasing VFS performance with increasing flow rates, VFS removal efficiencies over annual time scales may be significantly lower than the per-event values or averages typically reported in the literature and used in decision-making models. By applying a stochastic approach to a two-component VFS model, we investigated the extent of the disparity between two calculation methods: averaging efficiencies from each event over the course of one year, versus reporting the total annual load reduction. We examined the effects of soil texture, concentration-discharge relationship, and VFS slope to reveal the potential errors that may be incurred by ignoring the effects of temporal inequality in quantifying VFS performance. Simulation results suggest that errors can be as low as < 2% and as high as > 20%, with the differences between the two methods of removal efficiency calculations greatest for: (i) soils with high percentage of fine particulates; (ii) VFSs with higher slopes; and (iii) strongly positive concentration-discharge relationships. These results can aid in annual-scale decision making for achieving downstream water quality goals.