How is the water quality in Squaw Creek and its tributaries?  We have several ways to answer that question.

Today’s conditions in Squaw Creek

We can see real-time nitrate data from a sensor installed at Moore Park in Ames by IIHR Hydroscience and Engineering at University of Iowa, and compare that to other sites in their network on the Iowa Water Quality Information System.

7/18/2020 Update: The sensor is currently off-line for maintenance.  Based on monthly sampling, nitrate-N concentrations in Squaw Creek dropped back below 10 mg/L in July after rising to 15 mg/L in June.

Drain tiles (like this one, in Story County) provide an easy path for nitrogen to “leak” from crop fields.  Cover crops, bioreactors, saturated buffers, or wetlands are a good way to plug the leak!

Nitrate concentrations in Squaw Creek average around 6 mg/L.  Before the widespread use of commercial fertilizer, they would have been closer to 2 mg/L.  The drinking water standard is 10 mg/L.

Same-day comparisons

Prairie Rivers of Iowa helped the Squaw Creek Watershed Coalition organize two water quality monitoring “snapshots” in 2019, continuing a long tradition of citizen science.  In October 2019, 28 people tested 30 sites on Squaw Creek and tributaries in Ames, Story County, and Boone County for nitrate, orthophosphate, transparency, chloride, and pH.  Snapshot results going back to 2006 are available here.

Our “Watershed Matchup” series can help you interpret that data.  Looking at two creeks that were tested on the same day, you can begin to see the influence of different land uses and conservation practices.

Biweekly lab tests

  • Squaw Creek at Lincoln Way in Ames
  • East Indian Creek at S27 north of Maxwell

During the growing seasons of 2016, 2017, and 2018, City of Ames and Story County Conservation staff collected biweekly samples for these two sites and used automated sampling equipment to collect samples during storm events.  The City of Ames Laboratory Services tested these samples for nitrate, phosphorus, total supended solids, and E. coli.  Our handout explains what those things are!

We’ve been sharing the data on our website and partnered with ISU this spring to make sense of all the data with this final report.

2018 data

2017 data and technical report

2016 data and technical report

Takeaway messages:  

There’s poop in the water, so use caution and hand sanitizer when fishing or wading in the stream.  Squaw Creek has levels of fecal indicator bacteria (E. coli) that regularly exceed the primary contact recreation standard.  In a large watershed, it can be difficult to tell where it’s coming from, but testing of multiple sites by volunteers has helped us find and address sewer and septic issues in the past.  Some of our partners are exploring some intriguing new techniques for microbial source tracking that may help us distinguish human, livestock, and wildlife influences so we can better direct our efforts.

It turns out to be quite difficult to measure trends in nitrogen, and very difficult to measure trends in phosphorus (which tends to shoot up after a rainstorm).  You need a lot of data and a big improvement to pick out a signal from the noise of day-to-day and month-to-month variation.  Now that we have a baseline, we may come back and monitor again once we have a few more thousand acres of cover crops in the watershed, but for now we’re working with Story County and other partners to develop a comprehensive, locally-led water quality monitoring strategy.