To help us understand the movement of water through the QCCA wetland complex, we're installing three OnSet MicroRX Water Level Stations (RX2401). We will measure the water levels in streams entering and leaving the property as well as the level in the lake. The station in the lake is equipped with additional instrumentation to measure atmospheric variables.
Before deploying sensors in the field, "bucket tests" were conducted to ensure the sensors were operating correctly. In our case, we placed three sensors on a container that was filled with water to a known level. The data loggers were started and water level data were collected. The water level was altered multiple times to test the response of the sensors to changes in water level.
In the field, each water level sensor was housed in a stilling well. We use stilling wells made from 2" schedule 40 PVC. A 10 ft length of this pipe cost less than $5. Holes were drilled along the length of the PVC pipe to ensure the water level in the stilling well and the level in the stream or lake were equal. A cap with a purge hole was used to keep debris from gathering in the stilling wells.
The ground was so soft that we were able to drive the mounting pole almost 2 ft deep without using any tools. We followed this up with a few taps from a weighted post driver for good measure.
We used a standard 1-5/8" diameter 16 gauge galvanized chain link fence post. It was installed approximately 6 ft from the stream where the water level sensor was installed. Our system was equipped with a 10 meter (~33 ft) long cord to connect the sensor and the data logger which allowed us a degree of flexibility in where and how we mount the components.
A second set of hands is helpful when mounting the data station - especially in cold, wet, and muddy conditions! We were lucky to have ample help from members of the Moline Conservation Club - the group responsible for purchasing these systems.
Each data station is equipped with a solar panel that provides power for the data logger, the sensor(s), and the 4G cellular data connection.
We mounted the stilling well alongside a t-post that was driven into the stream bed and plumbed using a 2 ft level. This stilling well was 28" tall.
We took measurements of stream dimensions and water level. This stream was 6 ft wide with water depth ranging from 1.4 to 1.6 ft. We located the stilling well 2.6 ft from the right bank. These dimensions were representative of those measured up- and down- stream from the stilling well.
Before placing the sensor, we secured the stilling well to the plumbed t-post using heavy duty zip ties.
Finally, the water level sensor was placed in the stilling well and secured with an additional zip tie.
Photos by Roger Viadero, Jr., and Roger "Spike" Viadero, III.