Data collected and processed by L.A. Garcia, P.J. Terrio, and A.E. Manaster of the U.S. Geological Survey, in cooperation with the American Farm Trust and Macoupin Soil and Water Conservation District. Input data from the USGS National Water Information System (USGS, 2021) were used to run the Weighted Regressions on Time, Discharge, and Season-Kalman model and estimate outputs of daily, monthly and annual concentrations and flux for nitrate plus nitrite, total phosphorus, and suspended sediment for two sites in the Upper Macoupin Creek watershed.