Filling a grab sample with water at the Ousel Falls monitoring site.

The Task Force fills bottles with stream water from our 21 field sites. Then, we analyze these samples in a laboratory. Our staff adds chemicals to the water to cause a reaction, which turns the sample pink if there is nitrate present. The shade of pink varies with the concentration of nitrate in the sample.

After the reaction is complete, we analyze these samples using an instrument called a spectrophotometer. This instrument passes light through the sample to detect the intensity of the pink color and to quantify the amount of nitrate in the sample.

A row of pink samples ready to be analyzed for nitrate.

During our summer baseflow event, we collect our samples and send them to Energy Laboratories to be analyzed for nitrate, total nitrogen, and total phosphorus. Nutrient levels during the growing season have the biggest effect on river health, so we want to make sure data from our summer events are as accurate as possible.

The Montana Department of Environmental Quality (MT DEQ) funds our summer nutrient analyses through a program that supports volunteer water quality monitoring.