The Scientists in the River

Bruce and Joe pulled the four foot gar up from the Sangamon River. It was an impressive specimen, to be sure, long of snout and razor sharp of teeth, but his eyes has already been picked out. Mary imagined they may have been taken by foodie connoisseurs seeking the key ingredient for “Gar-eye soup”, which probably enhances virility, or something like that.

She was kidding. A little.

I was in another part of the river, upstream in a large backflowing “eddy”, neck deep at the time, thinking about gar’s teeth as I was feeling the bottom sloping down and away from my feet as I neared a steep, clay embankment. I started to swim for it.

I was seeking a submerged tree branch, approximately four feet in length, preferably having been in the river for a while, perhaps partially decaying, but still with plenty of bark intact. Bruce refers to this as a “snag”.

The water was quite still here in this deep backflow eddy, but a few feet behind me was a different story. Here, the entire river gets shallower and narrows into a gravelly, sandy-bottomed channel about 45 feet across that was, on average, barely 3 feet deep. The choppy river water rushed rapidly by, a somewhat unusual scene for the normally sleepy, meandering Sangamon.

We measured the water’s speed with a little floating whiffle-type golf ball. It was moving 10 feet in about 3 seconds, on average.

Bruce had lost the first whiffle ball on the first try on a toss to Joe, who was 10 feet upstream. Joe missed, the ball went into the current, whizzed past Bruce just under the surface and disappeared under a massive pile of “woody debris” about 100 yards downstream as Bruce chased after it to no avail.

Earlier, Joe and I had forded the river channel to the opposite bank, very carefully, maintaining solid footing against the impressive force of the river’s current. We needed to cross to post little orange landscape-marking flags along the opposite bank, precisely marking out 200 feet.

Meantime, Bruce, who also serves as photo-documentarian for our little scientific expedition, was on the shore taking pictures of butterflies while Mary carefully jotted field notes documenting everything relevant that she could about our site.

A Hackberry Butterfly landed on Mary’s field notes. Bruce rushed over to get the shot. He looked down and photographed a Red-spotted Purple on one of its favorite food sources, left by a canine visitor, that looks like a Milky Way, but it’s not.

He then turned and had Mike stand very still while he got a shot of another Hackberry perched on Mike’s favorite hat.

Our site was an expansive gravel and cobble-stone bar that extended well over halfway across the Sangamon located near the north end of the Riverbend Forest Preserve. You can also see pictures of this beautiful site and the five of us volunteer scientists, the gar and the butterflies on our Facebook page, or visit the site yourself at (or very near) GPS coordinates 40.187227, -88.420317.

After documenting the relevant facts at our picturesque site, Bruce and Joe collected two samples from the river, one an “undercut bank” on the opposite bank where the current was flowing fastest, and one from a snag that Bruce had collected. Bruce ultimately rejected as inadequate the snag I had collected during my brave swim across the eddy.

And he was right (as usual). The snag he collected from the swiftly flowing opposite bank was a veritable packed hotel of highly desirable caddis flies, an excellent find, and a clear indicator of a very healthy Sangamon River at this site.

After collecting the samples, the five of us sat on the gravel and cobble bank around Bruce’s plastic table, sitting on float cushions on overturned five-gallon plastic buckets. We sat there, heads bent down over river bottom muck and snags with little tweezers in hand and picked out all the macro-invertebrates we could spot and placed them in our little white tray of water for cleaning and preliminary ID.

After that, we dropped them in a solution of pure isopropyl alcohol where they die, presumably happy.

By now, you may be wondering why exactly we were all there.

We were a small team of five local volunteer “Citizen Scientists” participating in the USRC’s Annual Riverwatch program. Riverwatch monitors the Sangamon River’s health by gathering a scientific sample of the river’s macro-invertebrates, which are basically tiny, water-borne bugs.

Macro-invertebrates (not to be confused with “micro-invertebrates” which can’t be seen without a microscope) mostly consist of flies such as caddis flies, mayflies and dragonflies in their larval stages, which means they haven’t yet taken flight. These are the “good guys” to find when counting species. There can also be a variety of small bugs and worms such as bloodworms that are destined to never leave the water. These are not quite so good, but still important to identify for “species diversity”.

The reason I write this is to note that there was nothing special about our little expedition: for example, Mary is a nurse, Joe a retired contractor, and Bruce is a Mahomet Village Board member that delivers packages by day. Anyone reading this can be a volunteer scientist for a day with Riverwatch!

And while macro-invertebrate monitoring is winding down, the USRC will be hosting two upcoming mussel surveys, in addition to a Riverwatch Lab where volunteers do an “official” count and ID of our river sample. Visit for details.

In the end, it was a successful trip, with our citizen scientific expedition packing up happily, satisfied that we had gathered an impressive sample of macro-invertebrates that will again (just like past years) document the excellent health of the Sangamon River.

As the sky became cloudier and rain threatened I shoved the now fairly gamey and fly-covered gar (who incidentally does not qualify as a “macro-invertebrate”) back in the current of the Sangamon and he headed off downstream for his final river trip. Probably to end up in the woody debris pile 100 yards downstream.

And we Citizen Scientists all headed back home to mow lawns, wash decks, and do whatever non-scientists do on a balmy Sunday summer afternoon.

Appeared as Notes from the River, Mahomet Citizen, by Scott Hays, July 30, 2015

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