Guest post by Donny Roush

Ricky was insistent: “Are we gonna find a water penny this time? When will we see a water penny? I hope we catch one finally!” This was my fourth time guiding field work with Ricky’s 6th grade class. We were using kick nets to sample macroinvertebrates from the South Platte River in Denver, CO.

We’d already completed our other EarthEcho Water Challenge tests. We knew the river’s water had enough dissolved oxygen and proper pH to support pollution-sensitive critters. We had mayfly and caddisfly nymphs in our nets, as we’d come to expect.

Denver Public Works' Donny Roush leads a water education program for local students.

So, where were the water pennies? At the time – a few years ago – I wasn’t sure. On our identification poster, these cute beetle larvae were right there – between mayflies (which we had) and midges (which we had).

Ricky’s repeated inquiries drove me to Colorado aquatic ecology experts and the scientific literature. After a bit of digging, I found this statement: (from by Ward, Kondratieff and Zuellig’s An Illustrated Guide to the Mountain Streams Insects of Colorado [2002]) “…water pennies apparently do not occur in Colorado.”

I broke the news to Ricky the next time I saw him. I also decided I needed a better ID poster.


Aquatic macroinvertebrate keys tend to be rather generic. I’ve seen a couple of popular ones used all over North America.  

In 2015, I used local data to create watershed-specific macroinvertebrate tools for the South Platte and Middle Rio Grande rivers. They’ve been quite popular. So, when I needed to update my Denver poster this autumn, I decided to convert it into a template and clip art collection.

I call the result “Make Your Own Watershed-specific Macroinvertebrate Poster,” a ZIP file containing a PowerPoint-based template, 46 copyright-cleared line art illustrations of macroinvertebrate taxa, a table of credits, and an adjustable size range bar.

You can build a poster customized to your watershed.

The 2019 South Platte River poster has gotten rave reviews. I shared the package with colleagues during the Sustaining Colorado Watersheds and North American Association for Environmental Education conferences.  

Want to “Make Your Own Watershed-specific Macroinvertebrate Poster”? Send me a request at

Editor's Note: Donny Roush is a Water Educator with Denver Department of Transportation & Infrastructure, an EarthEcho Water Challenge partner. He leads a diverse set of hands on water education programs with students across the Denver region, engaging them in the EarthEcho Water Challenge and inspiring young leaders to take action to protect their local watersheds.