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!
Jess Lancial testing water quality (photo credit Story County Conservation)
Volunteer Water Monitoring in Story County
A round of applause for all the volunteers and Story County Conservation staff who have diligently been monitoring their assigned stream twice a month in all kinds of weather! Also, let’s give a shout-out to the people who work behind the scenes. Sara Carmichael of Story County Conservation keeps everyone on track and equipped with supplies. Heather Wilson of the Izaak Walton League of America provides training and support to volunteers around the state. We rely on the IWLA’s Save Our Streams program for training materials and the Clean Water Hub for data entry. The three of us will be meeting the volunteers at a training event later this month to kick off another great season.
Three ways to get involved:
There’s room for one or two more volunteers to cover a site in Story County, so contact Sara.
If you’d like to try water monitoring without committing to a schedule, Prairie Rivers organizes a one-day volunteer event in the Ames area each May, so keep an eye on our events page.
If you don’t live in Story County, the Izaak Walton League is launching a new Nitrate Watch program and you can request a bottle of test strips while supplies last.
In March, Prairie Rivers will release a report detailing the findings, but for now let’s admire the scale and consistency of the effort, which has really improved since last year. (Updated 2023-02-18 to include some data sheets that were entered late)
Sites tested at least once
Sites tested at least 10 times
Sites tested at least 20 times
Data sheets entered in the Clean Water Hub
Sites tested at least once
Sites tested at least 10 times
Sites tested at least 20 times
Data sheets entered in the Clean Water Hub
Story County Water Monitoring & Interpretation Plan, 2021-2030
Prairie Rivers partnered with Story County and 8 other organizationsto develop a ten-year Water Monitoring & Interpretation Plan for Story County. Regular communication between the various groups testing water helps avoid duplication and leads to new opportunities to improve water quality. Planning for how data can be used over the long term ensures that we get the most value from our time and effort. Read the plan here.
By my calculations, over 65% percent of the nitrogen load in Ioway Creek on May 20 came from less than 1 percent of the land area in the watershed. We still don’t know why.
Revised May 31
Many people assume that fertilizer applied to turf grass is a major source of nitrogen and phosphorus pollution in Iowa. At a presentation to the Ames City Council, I was asked if a public awareness campaign aimed at lawn care professionals and homeowners would be an effective way to improve water quality in Ioway Creek. If we’re talking nitrogen, I don’t think so:
Because turfgrass covers a tiny proportion of the land in most Iowa watersheds, compared to cropland.
Because turfgrass is a perennial. Having something growing and taking up available nutrients year-round is the principle on which cover crops reduce nitrogen loss.
Because there was a study by Dr. Keith Schilling that found very low nutrient levels in shallow groundwater below six Iowa golf courses.
To that list, I can add local water quality monitoring including lab testing and sensor results from May. Nitrate in Ioway Creek and the South Skunk River were the highest we’ve seen for a few years, but while rural tributaries ranged from 12-20 mg/L of nitrate, College Creek (an urban watershed with plenty of turf grass) measured only 2.3 mg/L.
But even if turf grass in general isn’t a serious water quality problem, maybe some specific areas of turf grass are a problem. That’s what I thought after reviewing the data from our spring water quality snapshot on May 17. Volunteers found a big difference in nitrate levels between South Duff Ave and other sites in Ames. I wondered if it could be a mistake, so I went back out on May 20 with a bottle of test strips and a smartphone app that enables more precise measurements. It wasn’t a mistake (nitrate in Ioway Creek increased from 8.6 mg/L to 24 mg/L in two miles), but the results still weren’t making sense, so I kept testing and testing until I assembled the map below. By my calculations, 65% of the nitrate load in Ioway Creek that day was coming from just 1,500 acres!
The 1,500 acres includes Coldwater Golf Links, and the pattern looks like what I’d expect to see if the golf course was overapplying fertilizer. However, the golf course superintendent has informed me that fertilizer has not been applied since fall, and then only at a low rate. A volunteer tested two ponds on the course and found low levels of nitrate (1-2 mg/L).
The 1,500 acres include some developed areas north of creek drained by storm sewers, but I tested water trickling from two outfalls on May 20 and found very low nitrate levels: 0.5 mg/L and 3.1 mg/L.
The 1,500 acres acres also includes two construction sites: a flood mitigation project near South Duff Ave and an ISU recreation complex east of Jack Trice Stadium. The photo shows severe bank erosion where drainage from the ISU construction site enters the creek. An inspector with the Iowa DNR noted problems with erosion control earlier this spring on the South Duff project. However, if the nitrate spike were linked to erosion, I’d expect to see high phosphorus and low transparency.
Honestly, I’m not sure what’s going on here. It’s not a pattern we’ve seen in previous years.
When interpreting this kind of data, there is a risk of jumping to conclusions and unfairly pointing fingers. In my first draft of this article, I suggested that Coldwater Golf Course was the source of the nitrate and the bank erosion. That was premature.
However, there is also a risk that we will waste time and money on the wrong solutions or the wrong areas if we don’t test water or don’t follow where the data is pointing. It’s clear from this month’s data and many other rounds of testing that water quality impacts are not uniformly distributed across the landscape.
Thanks to the 15 volunteers who helped to catch benthic macroinvertebrates (bugs) and test water quality over the weekend!
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!
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.
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.
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.
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!
Excuse the delay in posting the data. I had shared this with the participating volunteers but not with a broader audience. I was distracted by the dramatic change in water quality a week later. However, the results from the spring snapshot event is more typical of what we’ve been seeing this year–clear and drying up!
On the weekend of May 15, fifteen volunteers tested 25 sites on Ioway Creek and its tributaries.
Like most of 2021 so far, water levels were way below normal, and light rains Saturday afternoon did little to change things. A few volunteers tested their sites Sunday, but water levels had dropped back down by the time.
With streams running low and tiles not flowing at all, most sites were as clear as we can measure (transparency greater than 60 cm), had low nitrate (2 mg/L or less) and low phosphate (0.1 or less).
But there were a few interesting exceptions.
Nitrate concentrations were a little higher (5 mg/L) in the middle reaches of Ioway Creek, starting at Hwy E18 in Boone County and continuing to Moore Park in Ames. The upstream reaches in Hamilton County and the downstream reaches in Ames had low nitrate levels.
“Gilbert Creek” had higher nitrate (5 mg/L) and much higher phosphate (1 mg/L) than other sites. When streams are running low, effluent from wastewater treatment plants can make up a significant portion of streamflow and can have a big influence on water quality. When streams are running high, effluent becomes a small fraction of streamflow compared to runoff from cropland. Wastewater plants in Iowa are only beginning to install technology to improve nitrogen and phosphorus removal.
Some urban streams showed elevated chloride levels (125 mg/L), but still within Iowa standards for aquatic life (389 mg/L thresholds for chronic exposure). Road salt dissolves and makes its way into groundwater, so we can see it’s influence in spring and summer, but testing before and after winter storms can give us a clearer picture.
The little creek below Ames High School (SC23) had muddy water (transparency of 32 cm) and dissolved oxygen low enough to harm aquatic life. We know that when it does rain this creek gets a lot of stormwater runoff (the video we produced with City of Ames shows this in action) and construction could also be an influence.
I don’t have a good explanation for lower dissolved oxygen and transparency at other locations.
Thanks to our volunteers for spending a morning testing water! Our next event will be in October.