Nutrient and sediment concentrations and loads in the Steele Bayou Basin, northwestern Mississippi, 2010–14

Scientific Investigations Report 2017-5035
Prepared in cooperation with the U.S. Army Corps of Engineers, Vicksburg District
By: , and 

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Abstract

The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers-Vicksburg District, monitored streamflow, water quality, and sediment at two stations on the Steele Bayou in northwestern Mississippi from October 2010 through September 2014 to characterize nutrient and sediment concentrations and loads in areas where substantial implementation of conservation efforts have been implemented. The motivation for this effort was to quantify improvements, or lack thereof, in water quality in the Steele Bayou watershed as a result of implementing large- and small-scale best-management practices aimed at reducing nutrient and sediment concentrations and loads. The results of this study document the hydrologic, water-quality, and sedimentation status of these basins following over two decades of ongoing implementation of conservation practices.

Results from this study indicate the two Steele Bayou stations have comparable loads and yields of total nitrogen, phosphorus, and suspended sediment when compared to other agricultural basins in the southeastern and central United States. However, nitrate plus nitrite yields from basins in the Mississippi River alluvial plain, including the Steele Bayou Basin, are generally lower than other agricultural basins in the southeastern and central United States.

Seasonal variation in nutrient and sediment loads was observed at both stations and for most constituents. About 50 percent of the total annual nutrient and sediment load was observed during the spring (February through May) and between 25 and 50 percent was observed during late fall and winter (October through January). These seasonal patterns probably reflect a combination of seasonal patterns in precipitation, runoff, streamflow, and in the timing of fertilizer application.

Median concentrations of total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and suspended sediment were slightly higher at the upstream station, Steele Bayou near Glen Allan, than at the downstream station, Steele Bayou at Grace Road at Hopedale, MS, although the differences typically were not statistically significant. Mean annual loads of nitrate plus nitrite and suspended sediment were also larger at the upstream station, although the annual loads at both stations were generally within the 95-percent confidence intervals of each other.

Suggested Citation

Hicks, M.B., Murphy, J.C., and Stocks, S.J., 2017, Nutrient and sediment concentrations and loads in the Steele Bayou Basin, northwestern Mississippi, 2010–14: U.S. Geological Survey Scientific Investigations Report 2017–5035, 32 p., https://doi.org/10.3133/sir20175035.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods of Data Collection
  • Statistical Comparison of Data Sets and Calculation of Nutrient and Sediment Loads
  • Hydrologic Conditions
  • Concentrations and Estimated Loads and Yields of Nutrients and Sediment
  • Comparison of Nitrogen and Phosphorus Concentrations, Loads, and Yields to Historical Data, Other Agricultural Basins, and SPARROW Model Estimates
  • Summary and Conclusions
  • Acknowledgments
  • References Cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Nutrient and sediment concentrations and loads in the Steele Bayou Basin, northwestern Mississippi, 2010–14
Series title Scientific Investigations Report
Series number 2017-5035
DOI 10.3133/sir20175035
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Lower Mississippi-Gulf Water Science Center
Description viii, 32 p.
Country United States
State Mississippi
Other Geospatial Steele Bayou Basin
Online Only (Y/N) Y