In April, I joined a class of Ames High School seniors to survey benthic macroinvertebrates in Ioway Creek. If you had asked me “what on earth are you doing?” here’s what I would have said:
Hello! I’m Dan and I work on water quality for a local non-profit. And these are environmental science students from Ames High School. Why are we standing in the middle of the creek wearing hip waders and doing what looks like a funny dance? Why, this is a perfectly normal thing to do! We are citizen scientists and we are “science-ing”! The dance is called the benthic shuffle, and is an important part of the protocol for biological monitoring. We are dislodging aquatic insects from the rocks and catching them in our net.
And look at what we have caught from a mere 1 square meter of rocks! 170 mayflies! This too is normal! We are at Brookside Park, and here is a brook babbling over rocks and gravel. It would be strange if we did not find a healthy population of mayflies in such inviting habitat!
No, they don’t look like the mayflies that spatter windshields in Dubuque. But this is indeed Baetis, the blue-winged olive mayfly, imitated with success by many a trout fisherman. In its larval form, we call it the “small minnow mayfly”, for its quick swimming. They live about a year in the creek before they pupate and get their wings, assuming a fish doesn’t eat them first!
As I was saying, what you see here is perfectly normal, though maybe not as common as it should be in Iowa streams. If you find a riffle in the stream with no mayflies, well, that would mean something is not right. Perhaps insecticides have washed into the creek from upstream farms and lawns and killed them. Perhaps we’ve inadvertently fertilized the algae in the creek, turned the water a shade greener and the making the water a little less oxygenated at night. There are other insects that can make a living under these conditions. In the creek near the Story County Fairgrounds, you can find plenty of these net-spinning caddisflies, but no mayflies! If all you find are these wriggly little midge flies, well, that’s a sign of more serious pollution.
Nice to meet you! Time to get back to counting bugs!
Thanks to the 15 volunteers who helped to catch benthic macroinvertebrates (bugs) and test water quality over the weekend!
Volunteers capture benthic macroinvertebrates with a kick net, one of two methods we tried.
Ioway Creek “Snapshots” in May and October are a tradition going back to 2006. Volunteers test water quality at many locations on the same day to get a better picture of what’s going on in the watershed. Since the IOWATER program ended, Prairie Rivers of Iowa has gathered supplies and planned events to keep the tradition going, but this year there was just one little snag: there was barely any water in Ioway Creek or its tributaries!
For most of this fall, our usual gathering place at Brookside Park has looked more like the photo on the left.
Not a problem. The South Skunk River still had flowing water, and this was as good an opportunity as any to survey benthic macroinvertebrates (aquatic bugs), an indicator of water quality and habitat quality in rivers. We were helped in this task by Susan Heathcote, a trainer with the Izaak Walton League’s Save Our Streams program. If you’d like to become certified and missed out on this opportunity to complete the field portion of your training, keep an eye out for more training events with Susan in early spring.
Photo credit: Rick Dietz. Volunteers pick invertebrates off rocks and leaves and sort them in ice cube trays.
In addition to crawfish and dragonflies (always a hit with kids), we found a variety of smaller critters, including sensitive mayflies and stoneflies. Overall, the invertebrate community in the South Skunk River was “good.” In contrast, another stream we surveyed this week (West Indian Creek south of Nevada) had a “poor” score with mostly net-spinning caddisflies. We’ll discuss some possible reasons for this difference at a webinar on November 2nd.
Another option for when streams are dry is to spend some time interpreting the data we have. Following some water quality testing in the Skunk River, I gave a presentation to put those measurements into context. I think the data feels more relevant when you’re at the water’s edge and have just gone through the process of collecting it! If you prefer to do your learning somewhere warm and comfortable, we’ll be covering similar information at a webinar on November 2nd.
This fall, nitrate is zero in most streams that have any water, but over the past 15 years we’ve been able to see which tributaries have the highest and lowest levels.
Another hitch. Thunderstorms were forecast for Sunday! We changed the date to Saturday and are glad we did; the weather was beautiful. This also gave us the opportunity to set up equipment so we could capture water samples from the big rain on Sunday. Three volunteers helped me retrieve a dozen samples on Monday. The samples will be tested for E. coli bacteria and optical brighteners, which may help us find and fix septic and sewer leaks.
Ryan checks a crest stage recorder (a low tech tool for seeing how high the water got) and puts a fresh bottle in a storm sampler.
Many thanks to all who participated. We hope to see you at the next watershed snapshot in May, and hope the water levels will be back to normal!
Thirteen volunteers braved the cold on October 24 to test water quality in Squaw Creek, the South Skunk River, and their tributaries. For some, this was their 14th Fall Water Quality Snapshot. For others it was their first time doing stream monitoring. What we found defies easy categorization.
Update: The name “Squaw Creek” was officially changed to “Ioway Creek” in February of 2021, to be more respectful to native peoples. Over the next year, expect to see some changes to the names of the Squaw Creek Watershed Coalition and other groups that have formed to protect the creek, as well as maps and signs.
Volunteers Diane Birt, Paul Readhead, Liz Calhoun, and Rick Dietz take turns brushing off rocks to capture bugs in our net. The water was freezing!
By some indicators, water quality in Squaw Creek was good. Since I wasn’t sure how many creeks would be flowing when I planned this event, I added bug collection to the agenda to keep us busy. Excuse me. Benthic macroinvertebrate sampling. We were pleased to find tiny stoneflies and mayflies. They’re good fish food, ask any fly fisherman! Excuse me. An important part of the aquatic food web. These insects also act as a sort of canary in the coal mine. They need water with a lot of dissolved oxygen so will be rare or missing in streams with too much pollution, murky water, or not much in the way of habitat.
Fun fact: while the adult mayfly is notorious for living only 24 hours, the juvenile form (naiad) lives in the stream for several years. If you’re curious what adult mayflies and stoneflies look like, I found somephotos from our neighbors in Missouri.
By some indicators, water quality in Squaw Creek and it’s tributaries was bad. As in, there’s poop in the water. Excuse me, fecal indicator bacteria. This month, E. coli bacteria in Squaw Creek continued to exceed the primary contact recreation standard, and College Creek jumped above secondary contact standard. I wondered if this spike might be due to accumulated… debris… being washed out of the storm sewers and off the landscape by the 1.25 inch rain we received Thursday and Friday, but the lab samples were actually collected on Wednesday Oct 21, so I’m not sure. Anyway, covid-19 is not the only reason I bring hand sanitizer to these events!
By some indicators, water quality was unusually dry this fall. Nitrate was too low to detect at 13 of 16 sites we tested. Under wetter conditions, as we had this spring or last fall, nitrate in these same streams was higher and differences due to landuse or conservation practices in the watershed become more apparent.
Site
Watershed
Fall 2020
Spring 2020
Fall 2019
Squaw Creek @ Duff Ave
Rural and urban
0
10
5
Bluestem Creek @150th St
Rural
2
10
5
Glacial Creek @ U Ave
Rural (with a constructed wetland)
0
2
2
College Creek @ University
Urban
0
2
2
Nitrate-N concentrations, in mg/L
Water quality is rarely all good news or all bad news. Citizen science can us a more complete picture.
