Reducing Nutrient Pollution

Problem

How can approaches be improved to meet load-reduction goals more efficiently for the Chesapeake Bay watershed?

• With increasing intensity of severe storms causing high-flow events, a focus on "hot spots" does not account for a small percentage of locations and events that contribute to the vast majority of total annual pollution loads.

Findings

Researchers analyzed eight years of data from 108 sites in an established monitoring network, looking at daily-scale records of flow and corresponding loads of total nitrogen, total phosphorous, and total suspended sediment at each gauging station.

• Their innovative application of a formula normally used in economics to quantify inequity in wealth distribution allowed them to measure the degree of inequality of loads and identify periods of time and corresponding flow conditions to target.

Impact

The study's conclusions propose a critical shift in approaches to meeting load-reduction goals from "everything, everywhere, all the time" to "finding the right solutions in the right places that work at the right time," allowing watershed planners and managers to develop low- and high-flow targets for nutrient and sediment loads specific to each watershed in the bay's 64,000-square-mile basin.

Research Credit

Team

• Heather Preisendanz, Tamie Veith, Qian Zhang, James Shortle

Participating Departments

• Agricultural and Biological Engineering
• Agricultural Economics, Sociology, and Education

Partners

• USDA Agricultural Research Service Pasture Systems & Watershed Management Research Unit
• Penn State Institutes of Energy and the Environment
• University of Maryland Center for Environmental Science, U.S. Environmental Protection Agency Chesapeake Bay Research Program

Federal and State Appropriations

• USDA NIFA Hatch Multistate Projects PEN04574, Accession # 1004448

Emerging Discoveries

'Windows of opportunity' crucial for cutting Chesapeake nutrient, sediment loads

December 14, 2020

The vast majority of nutrients and sediment washed into streams flowing into the Chesapeake Bay are picked up by deluges from severe storms that occur on relatively few days of the year. That is the conclusion of a new study led by Penn State researchers, who say it offers clues for cleaning up the impaired estuary.

Published Research

Temporal inequality of nutrient and sediment transport: a decision-making framework for temporal targeting of load reduction goals.

• Preisendanz, H. E., Veith, T. L., Zhang, Q., & Shortle, J. (2020). Temporal inequality of nutrient and sediment transport: a decision-making framework for temporal targeting of load reduction goals. Environmental Research Letters, 16(1), 014005. https://doi.org/10.1088/1748-9326/abc997