Story County Water Quality Monitoring

We’ve been testing more Story County streams than ever and introducing new ways to make sense of the data.

If you see a car stopped by a bridge in Story County pulling up a milk jug of water on a rope, there’s a good chance it’s me or volunteer Rick Dietz, doing our monthly monitoring route.  We collect water samples from 10 sites, and the City of Ames staff covers another five.  Laboratory Services for City of Ames Water and Pollution Control tests the samples for nitrate, total phosphorus, total suspended solids, E. coli bacteria, and fecal coliform.

The support of a certified lab provides a backstop for volunteer monitoring and allows us to make direct comparisons with data collected from larger rivers by the Iowa DNR.  It also allows us to test for E. coli bacteria, which have exceeded the recreational standard in every stream we’ve tested.

The most surprising result so far is the high phosphorus levels in West Indian Creek.  Phosphorus is a nutrient that contributes to algae blooms.  Phosphorus and E. coli increase between Lincoln Highway (where the creek enters Nevada) and Jennett Heritage Area (about 5 miles downstream), so there’s a good chance that treated wastewater or untreated stormwater from the city could be a source.  Fortunately, the City of Nevada has projects underway that could help clean it up. Nevada will be constructing a new wastewater treatment plant starting in 2022.  That opened up a grant opportunity (an SRF sponsored project) that could pay for bank stabilization or stormwater treatment projects in and around town. We’re happy to be included in the conversation and to provide water monitoring data that can strengthen the City’s grant application.

The graph above was produced with “R”, a free open-source software package for statistics and data science.  We like the idea that our work will be transparent and repeatable.  Doing an analysis for the first time is difficult (a bit like computer programming) but doing an analysis for the second time (with more recent data, a different site, or a different pollutant) is ten times faster, and there are many options for sharing the data, which we’re just beginning to explore.

View more results from 2020 water monitoring here.