Total Phosphorus composite monitoring data set for 52 lakes.

Surface water monitoring data from national aquatic surveys (lakes, streams, rivers). This dataset is associated with the following publication: Stoddard , J., J. Van Sickle, A. Herlihy, J. Brahney, S. Paulsen , D. Peck , R. Mitchell , and A. Pollard. Continental-scale increase in stream and lake phosphorus: Are oligotrophic systems disappearing in the U.S.?. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 50(7): 3409-3415, (2016).

Surface water monitoring data from national aquatic surveys (lakes, streams, rivers). This dataset is associated with the following publication: Stoddard , J., J. Van Sickle, A. Herlihy, J. Brahney, S. Paulsen , D. Peck , R. Mitchell , and A. Pollard. Continental-scale increase in stream and lake phosphorus: Are oligotrophic systems disappearing in the U.S.?. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 50(7): 3409-3415, (2016).

The Archive.zip data set contains R source code and inputs and selected outputs associated with regression analyses used to estimate total phosphorus loads for selected sites on Great Lakes tributaries for water years 2014–2018

The Archive.zip data set contains R source code and inputs and selected outputs associated with regression analyses used to estimate total phosphorus loads for selected sites on Great Lakes tributaries for water years 2014–2018

Phosphorus, nitrogen, chloride, and suspended-sediment loads, in 24 U.S. tributaries of the Great Lakes, were estimated using U.S. Geological Survey (USGS) data from the Great Lakes Restoration Initiative (GLRI) monitoring program for the period Oct 2010 through Sept 2023 (USGS water years 2011-23). Specific water-quality constituents include total phosphorus, orthophosphate, particulate phosphorus, total nitrogen, nitrate plus nitrite, ammonium plus ammonia, chloride, and suspended sediment. Concentrations and loads, including actual and flow-normalized estimates, were estimated with Weighted Regression on Time, Discharge, and Season (WRTDS). Results are reported at daily and annual time steps in this data release and via an interactive web application (https://rconnect.usgs.gov/glritrends). This data release is an update of a previous version for water years 2011-20. Major changes include the addition of data from water years 2021-23 and the addition of chloride to the constituents.

This dataset allows the user to explore the potential impacts of various environmental and anthropogenic drivers on observed growing season total phosphorus concentrations in lakes and streams across the United States.

This dataset allows the user to explore the potential impacts of various environmental and anthropogenic drivers on observed growing season total phosphorus concentrations in lakes and streams across the United States.

Phosphorus, nitrogen, and suspended-sediment loads, in 24 U.S. tributaries of the Great Lakes, were calculated using U.S. Geological Survey (USGS) data from the Great Lakes Restoration Initiative (GLRI) monitoring program for the period Oct 2010 through Sept 2020 (USGS water years 2011–2020). Total phosphorus, orthophosphate, particulate phosphorus, total nitrogen, nitrate plus nitrite, ammonium plus ammonia, and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment exported downstream at each tributary site. Daily loads were estimated using the WRTDS method with Kalman filtering. To determine the change in loads between the first and last water year in record, the annual load results were flow-normalized to standardize among years with varying flow dynamics. Three primary data tables are provided that describe phosphorus, nitrogen, and suspended-sediment conditions at 24 tributaries across the U.S. Great Lakes watershed: (1) annual results, (2) daily results, and (3) changes results. The annual table is organized by USGS water year (defined as Oct 1–Sept 30). The annual and daily tables also include time-weighted mean concentrations, mean discharge, and yield estimates, the latter being calculated by dividing loads by watershed areas. Descriptions for data tables are provided in the DataDictionary.csv file. Results are also displayed in an interactive web application (https://rconnect.usgs.gov/glritrends). This data release also contains a model archive. The “model_code.zip” file contains the R code and input data to run the models, generate the results, and display the results on a shiny application. The Readme.md file includes instructions of how to run the model and descriptions of all inputs, model arguments, and outputs. Each model (saved as an eList) contains the input data (USGS station information (i.e., site information), daily discharge, and water sample data), model parameters, estimated values, and bootstrapped results. All eLists are archived in the “model_archive” folder, which is organized by sample dataset (i.e., allsamples and midsamples) and are named with the parameter and station number (e.g., NH4_04024000.RData). The RData files used in the shiny application are archived in the “shinydata” folder.

The USEPA participated in the 2015 Cooperative Science and Monitoring Initiative (CSMI) focus year for Lake Michigan. This work is describd here: http://www.iiseagrant.org/pdf/LakeMichiganCSMI2015FullReport.pdf As a small sub-component of this work EPA staff collected water quality data at the locations listed in grand_musk_tp.csv. The fields in grand_musk_tp.csv are described in grand_musk_tp.metadata.csv. This data was collected to support (provide validation data for) EPA nearshore nutrient modeling work described in the paper (in prep.) “Nearshore Nutrient Circulation in the Great Lakes - can a simple model provide transparency and utility?”.