The Mystery of the Orange Creek

The Mystery of the Orange Creek

orange colored water in a creek

“Is this pollution?”  I received this photo, taken at 1PM on March 24, from Ames High School student Oskar Niesen.  I met Oskar and other students in Mr. Todd’s environmental science classes for the first time in February, when we talked in the classroom about issues and solutions in Iowa waterways.  The class was interested in testing water quality, so I met them again at the creek on March 22 and showed them how.

Let’s call the site of the incident “Ames High Creek.”  It joins Ioway Creek near the disk golf course and originates with a 60 inch storm sewer pipe near the Richard Pohl Memorial Preserve (Ames High Prairie).  The pipe drains several neighborhoods in north Ames (including mine) that were built before modern development ordinances requiring detention ponds.  I’ve taken video of the torrent of water that comes out of the storm sewer after a heavy rain, and have seen the bank erosion it causes.  I’ve also tested the water after rains and found high levels of bacteria, sediment and phosphorus levels in this creek during heavy rains.  If people don’t pick up their trash, pet waste, or yard waste, there’s nothing to stop it from washing into to the creek.  So I was prepared to answer “yes, the orange-brown color must be pollution.”

Later that evening, I visited the site and chatted with Jake Moore and Liz Calhoun with the City’s stormwater program.  If someone had let muddy water wash off a construction site, or someone was pouring chemicals down the storm sewer, this would violate city ordinances and they would be the people to check up on it.  But the timing wasn’t consistent with construction site runoff.  There hadn’t been more than trace rain since Tuesday March 22nd.

orange stain at water's edge

 Oskar had talked with a geology professor at Iowa State (Dr. Elizabeth Swanner) and suggested another possibility: iron oxide (rust), perhaps formed by naturally occurring bacteria.  As Oskar explained “there are generally 3 types of iron oxide formations. One is a stain that we see now, the second is called flocculent iron which is a cloud that I saw then, the third is an iridescent film on the top.  Bacteria tend to form all three.” At 5:00 on March 24, when I followed up on Oskar’s tip, the water had cleared up and there was no iridescent film, but there was stain on the rocks and at the water’s edge all the way up to the storm sewer outlet.

water flushed from hydrant

Hydrant flushing is done every year with the express purpose of flushing out iron oxide and other mineral deposits that can clog water mains.  Liz Calhoun confirmed that crews flushed hydrants in neighborhoods connected to this storm sewer on March 24.  A little rust in water can stain laundry but is harmless to people and fish.  A release of drinking water can kill fish if it causes a sudden temperature change (this happened last summer when a water main broke) but in this case, we think there’s nothing to worry about.  Mystery solved!  The only thing more gratifying than working with curious young people and helpful colleagues is a happy ending for water quality!

Our October 2021 volunteer monitoring event is a little different

Our October 2021 volunteer monitoring event is a little different

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!

Upgrade your sewage treatment plant, get a free bioswale!

Upgrade your sewage treatment plant, get a free bioswale!

Does the State Revolving Fund (SRF) do infomercials for its Clean Water Loans?  I think they should because SRF Sponsored Projects are a classic case of “buy-one-get-one-free.”

We usually focus on conservation efforts by farmers but today let’s give some credit to the municipal wastewater departments—they do a lot to keep our rivers clean.  As a nation, we’ve generally been more successful in regulating and treating the pollutants coming out from sewage treatment plants and factories than we have been in dealing with the pollutants that wash off of farm fields, turf grass and parking lots.  We’ve now reached a point where the water coming out of the local sewage treatment plant is cleaner in some respects than the water in the backyard creek.  I’m not kidding: Ames Water and Pollution Control can’t exceed 126 E. coli colonies per 100mL in their treated effluent—E. coli levels in Squaw Creek for 2016 were eight times higher.

Repairing an aging sewer system or installing a UV disinfection system to meet permit requirements isn’t cheap.  This year, the City of Gilbert will be borrowing $3.8 million from the State Revolving Fund (SRF) to upgrade its lagoons and the City of Ames will be borrowing $21 million to prevent inflows to its sanitary sewer system.  With that necessary expense comes an additional opportunity to clean up Squaw Creek.  A city can apply to do SRF Sponsored Project of up to 10% of the wastewater loan principal, and have the project cost offset by reduced interest rates.  Eligible projects include “green infrastructure” in town, conservation practices on farmland in the watershed, or erosion control and ecological restoration along the stream.


Ames has done SRF Sponsored Projects before, so on Monday I joined staff from Gilbert, Fox Engineering, and IDALS to hear from Ames Stormwater Specialist Jake Moore and get some ideas for projects.  Paved surfaces like parking lots can contribute to erosion, flooding, and water quality problems, because the rain that falls on them rushes via storm sewer to our waterways.  Modern ordinances require that more stormwater be detained and treated on site, or allowed to soak into the ground rather than running off the surface.  Ames rebuilt the city hall parking lot last year to absorb water.  The parking stalls are permeable pavers.  Up to 27 inches of stone underneath provides storage space for water after big storms to mitigate flooding.  Compost amendment to the landscaped areas around the building increase soil permeability and promote healthy vegetation.  The site was recently planted with the help of Ames High School students, so check back—over time the moisture-tolerant native plants in the bioswales should fill in and bloom, attracting butterflies.

Cool project, right?  Prairie Rivers of Iowa is eager to partner with Gilbert, Ames, and other towns in the Squaw Creek and South Skunk watersheds to help facilitate water quality practices both in town and on farmland.