Healthy river flowing through farmland with data visualizations, contrasting with a polluted stream.

Revitalize Our Rivers: Unveiling the Secrets to Cleaner Waterways

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Theo Raines in Climate & Environment April 2025 • 4 min read.

"Dive into a 20-year study on nutrient transport in the Mississippi River Basin and discover practical strategies for safeguarding our water quality. Learn how long-term agroecosystem research reveals the key to reversing pollution and restoring aquatic health."


For decades, nitrogen and phosphorus pollution has cast a long shadow over our water resources, threatening drinking water, harming aquatic ecosystems, and fueling the infamous hypoxic zone in the Gulf of Mexico. The Mississippi River Basin (MRB), a vital artery of American agriculture, contributes significantly to this problem. Grain crop and livestock production account for 70% of the N and P transported within the basin, making it crucial to understand and address this source.

Recognizing the urgent need for action, researchers and policymakers have been working tirelessly to identify the most effective strategies for mitigating nutrient pollution. Within the MRB, the Salt River Basin (SRB) stands out as an area with particularly high phosphorus transport and intermediate nitrogen transport, highlighting the need for targeted interventions.

Enter the Goodwater Creek Experimental Watershed (GCEW), a dedicated research site established in 1991 to unravel the complexities of nutrient transport in agricultural landscapes. For two decades, scientists have meticulously monitored nutrient concentrations at various scales, from individual plots to entire watersheds, generating a wealth of data and valuable insights into the factors driving water quality.

Decades of Dedication: Unearthing the Data Goldmine

Healthy river flowing through farmland with data visualizations, contrasting with a polluted stream.

The Goodwater Creek Experimental Watershed (GCEW) study meticulously collected data from 1991 to 2010, tracking nutrient concentrations at plot, field, and watershed scales. This data is now accessible through the Sustaining the Earth's Watersheds-Agricultural Research Data System (STEWARDS), providing a valuable resource for researchers and policymakers. These findings are complemented by data sets from broader regional studies and cave stream monitoring, offering a comprehensive view of nutrient dynamics across diverse environments.

Throughout the 20-year study period, analytical methods for measuring nitrogen and phosphorus species in water samples remained consistent. Researchers employed automated colorimetry using flow injection or discrete analyzers to determine dissolved nitrogen and phosphorus forms. Quality assurance measures included rigorous duplicate, spike, and blank samples to ensure data reliability.
Significant analytical consistencies were present over the 20-year study:
  • Consistent Methods: Automated colorimetry techniques maintained over the study duration for accuracy.
  • Stringent QA: Inclusion of duplicate, spike, and blank samples ensured high data reliability.
  • Multiple Instruments: Use of Technicon, Lachat QuikChem, and Konelab Aquakem analyzers to enhance sample throughput and reduce waste.
  • Data Accessibility: Public access to data via STEWARDS promotes transparency and further research.
The long-term research at the GCEW and surrounding areas has yielded critical findings about nutrient transport in agricultural watersheds. Stream nutrient concentrations often reached levels associated with nuisance algal growth and reduced aquatic invertebrate diversity, signaling ecological stress. Fertilizer management practices emerged as key levers for reducing nutrient transport in runoff. Despite the presence of claypan soils, nitrate leaching remained a significant pathway for nitrogen loss, leading to groundwater contamination when fertilizer and manure inputs exceeded crop requirements. The most vulnerable areas for nutrient, sediment, and herbicide transport were field locations that had the poorest crop growth.

Turning Knowledge into Action: A Path Forward

The wealth of data and insights generated by long-term agroecosystem research provides a solid foundation for developing targeted and effective strategies to mitigate nutrient pollution. By embracing sustainable agricultural practices, optimizing fertilizer management, and focusing on soil health, we can revitalize our rivers and create a cleaner, healthier environment for future generations.

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