Stream Temperature Study


In late March and early April, HMN trainees Morgan and Ben Martindell and members Adrie Voors and Carl Droms were among a group of 49 who volunteered to deploy temperature loggers for Trout Unlimited’s Upper Shenandoah Stream Temperature Study. The group included several other members of the trainee class.

The first step in the process was to attend a training session at JMU organized by the study leaders, Jake Lemon and Seth Coffman, where we were told about the study: its purpose and scope, and the protocols to be followed. At the end, we were issued our supplies, which included the temperature loggers, as well as several 24″ long pieces of rebar.

As you may have guessed, the purpose of the study is to monitor the temperature in several streams in the Shenandoah River drainage. As global air temperature rises, the effect on stream temperatures will be different at different locations. For example, a stream fed by an underground source will not warm up as much on a warm day as one fed mostly by surface water. Trout Unlimited’s interest in this comes from the fact that trout thrive in cold water streams, but do poorly if the temperature gets too high.

templogger.350Our little group was given four locations on Beaver Creek near the village of Spring Creek in southwestern Rockingham County. After locating a site using the GPS coordinates we had been given, one of us waded into about the middle of the stream and pounded one of the pieces of rebar into the stream bed until only about 5″ protruded above ground. The temperature loggers (see photo at right) are encased in PVC pipe with holes that allow water in, with one set of holes reserved for sliding the whole thing over the rebar. Hose clamps tightened around the rebar above and below the logger keeps it in place.

We were instructed to locate the loggers near the given sites, with a couple of other considerations: they should be shaded during the day if possible, and they should be located in a spot that will remain underwater even during the driest part of the summer.

Our first attempt a placing a logger was complicated by the fact that there had been a torrential rain a few days before, which meant that the stream was much too fast and deep to be able to pound in the rebar (ever tried swinging a hammer under water?) Thus, we were forced to wait a few days for the water to recede. However, in the end we were able to place three of our four loggers without much difficulty. The fourth location was on private property whose owner politely declined to allow us onto his land.

The loggers will sit in the streams until September, when we will go to retrieve them. We’re keeping our fingers crossed that we can find the locations again, and that the loggers will still be where we put them!

– Carl Droms, Cohort II, April 2017

Top photo is of Morgan Martindell, Carl Droms and Ben Martindell at Beaver Creek Site Number 1 on April 5th taken by Adrie Voors.