Annually, the WPLMN analyzes recently collected data to track water quality trends.

Calculated daily pollutant load concentrations are used to create the maps below which are separated by parameter and display the most current data available. Each parameter’s data is displayed by average annual flow weighted mean concentrations as well as yield.

To analyze these parameters by site, watershed, or year, use the WPLMN data viewer. Use the data to compare the runoff/precipitation data found below. Sample and flow datasets are also listed below.

Major watershed pollutants

Yields and flow weighted mean concentrations by monitoring site watershed

Total nitrogen

Nitrate+nitrite nitrogen (NO3+NO2 – N)

Total Kjeldahl nitrogen (TKN)

Total phosphorus (TP)

Dissolved orthophosphate phosphorus

(In 2016: Not sampled at all sites and permanently discontinued for subwatershed sites)

Total suspended solids (TSS)

Mississippi River Basin

Pollutant loads as a percent of the load measured at Lock & Dam #3 near Red Wing, Minn.

Runoff/precipitation maps and data

Statewide variation in precipitation, the amount of that precipitation that ends up as runoff, and the ratio between runoff and rainfall (runoff ratio).