Temporal inequality of nutrient loads across several Chesapeake Bay gauging stations – assessing BMP effectiveness with lorenz inequality results

Authors: BIERTEMPFEL, JULIA - Pennsylvania State University; PREISENDANZ, HEATHER - Pennsylvania State University; Veith, Tameria - Tamie; RAJ, CIBIN - Pennsylvania State University

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2022
Publication Date: 4/15/2022
Citation: Biertempfel, J.E., Preisendanz, H.E., Veith, T.L., Raj, C. 2022. Temporal inequality of nutrient loads across several Chesapeake Bay gauging stations – assessing BMP effectiveness with lorenz inequality results[abstract]. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). P.1.

Interpretive Summary: No Interpretive Summary is required for this Abstract Only. JLB.

Technical Abstract: The Chesapeake Bay watershed is home to over 18 million people and contains over 87,000 working farms, which are two aspects that have contributed to the Bay’s long-standing impaired status. In response to the federal mandate to reduce pollutant loadings to the Bay and meet its portion of the watershed-wide load reduction goals, the Commonwealth of Pennsylvania has divided its counties into four prioritization tiers. Twenty watersheds within the Susquehanna and Potomac portions of the Chesapeake Bay were selected from among the tiers to compare watersheds with varying levels of documented best management practice (BMP) implementation to those dominated by forested land cover. Although spatial targeting of BMPs has been extensively studied for reducing nutrient and sediment loads from agriculturally-dominated landscapes of the Bay watershed, effectiveness of BMP implementation to restore natural biogeochemical variability to the nitrogen and phosphorus cycles remains unknown. Hydroclimatic variables, land use, soil properties, topography, and BMP implementation will be considered in a cluster analysis to determine key factors driving nutrient transport processes. Data analysis techniques, including concentration-discharge relationships, Lorenz Inequality, and corresponding Gini coefficients will be conducted at an annual-scale for each of the 20 selected watersheds. Patterns observed after the Chesapeake Bay Total Maximum Daily Load (TMDL) was enacted in 2010 will be compared to patterns prior to 2010. The results will enable a cross-watershed comparison of the temporal inequalities in flow and nutrient load, and of the ability BMPs to both reduce nutrient loads and restore natural biogeochemical variability within the studied timeframe. Research results will help land managers and policymakers assess the effectiveness of BMP implementation for achieving load reduction goals and for restoring variability to nutrient cycling.