Kristen Maps the River

We are fortunate to be able to work with many terrific volunteers and one in particular, Kristen Thiebault has been helping us with several projects that we would like to bring attention to. Kristen has been helping us with mapping projects of all kinds using geographic information systems (GIS) software. She is very knowledgeable in this field and has been willing to share her expertise with us. Kristen figured out a way to create a web app that shows trends in the results of monitoring data collected by volunteers over the years. This interactive web app show what happens to dissolved oxygen levels from one summer to the next, from 1997 to 2015. The color of each monitoring site changes according to how well dissolved oxygen levels can support aquatic life. The app can be found on the RiverWatch monitoring page of our website. Please take a moment to view the map and activate it by clicking on the play button in the time slider at the bottom.  

This screenshot of the DO app shows the DO oxygen levels during the summer of 2009–and the river’s corresponding ability to host aquatic life.

By watching the various sites shift between green, yellow and red you can see how variable the river’s conditions can be. A sight in Topsfield may be viable for supporting river life, but flanking it may be two sites in the red. Of note, is how often the headwaters fall into die-off levels. The headwaters are the lifeblood of the river, that they should so often be unable to support life indicate the amount of work that needs to be done for the upper watershed.


Some dramatic shifts, by looking at the dates, can be linked to drought years. Even in years when the river had enough water, we’re not looking at a line of green dots. This is indicative of other problems, such as stormwater pollution.


The information collected by our RiverWatch monitors is highly useful to our work, and we hope that Kristen’s new app throws new light and perspective on it for others.