river monitor in place

Monitoring our river

The first monitoring station was put in service on the Little Manistee on April 26, 2020. It is located a mile or two upstream from Bear Track Campground and 18 Mile Bridge. The purpose of the monitoring stations is to give us a base line of data from which to track the condition of the river over time. We recognize that the Little Manistee River is in very good condition. With the monitoring stations we collect Temperature, Depth and Conductivity data on the river multiple times a day. Over time we will build a database that shows us what the river in the current state looks like as conditions and seasons change. If in the future we see trends or large deviations from the base line develop we can recognize them and investigate causes and corrective action.

You can see the data at: https://monitormywatershed.org/sites/LMA/.
Take a few minutes to click on the icons in the blue bands across the top of the small graphs to get larger versions of the graphs you may find interesting. The system is still in development and can be slow to respond.

Another benefit of the monitoring station is that fishermen, kayakers and others can look at the water levels on the web and use the information to decide if the levels are in the optimal range for the activity they plan. It will take a while for everyone to learn what levels they feel are appropriate for their activities. When you visit the river it‘s a good idea to look at the river and the water level data on the internet and consider how they correspond so over time you develop an understanding of what the levels mean.

The Mayfly Data Logger we are using was developed at the Stroud Water Research Center and was brought to our attention by Trout Unlimited as part of their project to find inexpensive ways to monitor conditions on waterways throughout the nation and the world. The computer in the Mayfly is an enhanced version of the popular Arduino computer used by hobbyists. A basic Arduino computer can be purchased for under $25. The enhanced Mayfly version with additional inputs and outputs, a real time clock and microSD card reader/writer as well as other features directed at monitoring stations is about $60. When you combine the Mayfly with a scientific grade sensor, in our case a Conductivity, Depth and Temperature sensor you can get a monitoring station in the river for about $1500. This is about a tenth the cost of a USGS monitoring station in place on may rivers. Additional savings are achieved by using volunteers to maintain and monitor the stations. The maintenance on a USGS monitoring station we inquired about a few years ago was $17,000 annually, it does have some advanced features the Mayfly does not.

The temperature data will give us a base line on a very important characteristic for a coldwater stream. Temperature is important because colder water holds more dissolved oxygen required by the coldwater species now in the Little Manistee. Building development that removes vegetation that shades the river can cause the river to be warmed by the sun. The “hard surfaces” associated with development also cause storm water to run off directly into the river instead of being absorbed into the ground and cooled first. We estimate about 90% of the river water is from ground water sources. You can already see daily cycles in water temperature caused by the sun in our data. You can also see that when it rains and the river level rises from the additional surface runoff the water temperature also rises.

This monitor also measures the conductivity of the water in microsiemen (Also Known As Micro MHO’s) per centimeter. It gives a general idea of the dissolved solids in the water, like road salt. Distilled water has a conductivity ranging from 0.5 to 3 µS/cm, while most streams range between 50 to 1500 µS/cm. Freshwater streams ideally should have a conductivity between 150 to 500 µS/cm to support diverse aquatic life.
The monitor also measures the depth of the sensor below the surface of the river in mm. 25.4 mm is one inch, so 520 mm is about 20.5 inches. At the monitoring location the water is near base flow at 520 mm and very clear. Bank full at the monitoring location is about 950 mm and the water is dark.

The data is gathered (mostly) daily at this point from mocroSD cards in the monitor and manually uploaded to the internet. We are developing radio and internet connection capabilities to take the data and upload it to the internet in real time. We hope that will happen this summer, it is a larger task than we thought. Ultimately, we plan several stations to fully monitor the river along its length.

sensor in the river