NUTRIENT MASS BALANCE AND TRENDS, MOBILE RIVER BASIN, ALABAMA, GEORGIA, AND MISSISSIPPI

• Published in: Journal of the American Water Resources Association Vol. 40; no. 3; pp. 765 - 793
• Main Authors: Harned, Douglas A., Atkins, J. Brian, Harvill, John S.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-2004; American Water Resources Association
• Subjects: correlation analysis; Earth sciences; Earth, ocean, space; Exact sciences and technology; Freshwater; Hydrology; Hydrology. Hydrogeology; mass balance; Mobile River; nonpoint source pollution; nutrient loads; nutrient trends; water quality; Mississippi; Georgia; Alabama; United States; USA, Mississippi, Tombigbee R; USA, Georgia; ASW, USA, Alabama, Mobile Bay; USA, Tombigbee R; USA, Georgia, Etowah R; USA, Alabama, Alabama R; USA, Alabama, Mobile R; USA, Alabama, Black Warrior R; USA, Mississippi; tributaries; mass balance; fertilizers; nitrogen; streams; regression analysis; effluents; concentration; pollution; North America; nutrients; drainage basins; point sources; land use; water quality; fixation; phosphorus
• ISSN: 1093-474X; 1752-1688
• DOI: 10.1111/j.1752-1688.2004.tb04458.x

Results are presented from the first systematic estimation of nutrient input and output fluxes for major river basins in the Mobile River Basin, which covers parts of Alabama, Mississippi, and Georgia. Estimates of the total mass of nutrients entering each of the 18 subbasins were made by accounting for atmospheric deposition, fertilizer use, nitrogen fixation by agricultural crops, farm animal waste, and point-source inputs. Estimates of the total mass of nutrients leaving each subbasin were made by calculating the amount of nutrients removed by crop harvest and instream nutrient loads. Results show that N inputs from animal waste were largest in 12 of the 18 subbasins, while the second largest input was generally from atmospheric deposition, which was the greatest source in six of the subbasins. Fertilizer inputs and crop-related N fixation were the third and fourth most important N sources, respectively. Animal waste inputs also dominated the P sources, while fertilizer input was the main source in three of the subbasins, and point sources were important in several. Multiple regression analysis indicated a distinct association between water quality in the streams of the basin and agricultural activities. Results are presented from a trend analysis of the water-quality data.