Continuous Monitoring and Bayesian Estimation of Nutrient and Sediment Loads from Illinois Watersheds, for Water Years 2016–2020

Scientific Investigations Report 2021-5092
Prepared in cooperation with the Illinois Environmental Protection Agency
By: , and 



The State of Illinois is one of the leading contributors of nitrogen, phosphorus, and suspended sediment to the Mississippi River and the Gulf of Mexico. During water years 2016–20, the U.S. Geological Survey, in cooperation with the Illinois Environmental Protection Agency, operated continuous monitoring stations on eight major rivers in Illinois to better quantify nutrient and sediment loadings from the State of Illinois to the Mississippi River. This report estimates nitrate, phosphorus, and suspended-sediment loadings over that period, which can provide a benchmark against which to assess future changes in loading.

In addition, this report develops a new method for incorporating the uncertainty created by gaps in continuous datasets based on Bayesian machine learning. Data gaps are a common problem in continuous monitoring, and gap filling is necessary to quantify loadings and the uncertainty in loadings, which is essential if these results are to provide a benchmark for future studies. The uncertainty estimates may also be useful in an operational context, and this report provides examples of how uncertainty can be used in monitoring-network design and potentially reducing monitoring costs.

Suggested Citation

Hodson, T.O., Terrio, P.J., Peake, C.S., and Fazio, D.J., 2021, Continuous monitoring and Bayesian estimation of nutrient and sediment loads from Illinois watersheds, for water years 2016–2020: U.S. Geological Survey Scientific Investigations Report 2021–5092, 40 p., 10.3133/ sir20215092.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Purpose and Scope
  • Methods
  • Data Coverage
  • Streamflow and Discrete Water-Quality Data
  • Imputation Results
  • Comparison Among Model Forms
  • Loads and Yields
  • Continuous Monitoring and Discrete Sampling
  • Network Improvements
  • Summary
  • References Cited
  • Appendix 1. Station Descriptions
Publication type Report
Publication Subtype USGS Numbered Series
Title Continuous monitoring and Bayesian estimation of nutrient and sediment loads from Illinois watersheds, for water years 2016–2020
Series title Scientific Investigations Report
Series number 2021-5092
DOI 10.3133/sir20215092
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston VA
Contributing office(s) Illinois Water Science Center, Central Midwest Water Science Center
Description Report: vii, 40 p.; Data Release
Country United States
State Illinois
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details