Watershed Matchup #3: College Creek VS Bluestem Creek

This post is part of a series for 2019 Watershed Awareness Month, comparing water quality in a pair of local creeks to learn how land and people influence water.

With such a big watershed—147,000 acres—we’ll need the help of a lot of people to improve water quality in Squaw Creek.  However, some of the people I talk to assume that water quality is mostly someone else’s problem—it’s the CAFOs fault, or the golf courses, or the residential lawns.

By comparing smaller streams, volunteer monitoring can help us untangle some of the influences and serve as a reality check on the finger pointing.  Thanks to the Squaw Creek Watershed Coalition we have some data on a lot of Squaw Creek’s tributaries, some with urban watersheds (College Creek) and some with rural watersheds, some with hog barns (Prairie Creek) and some without (Bluestem Creek).  Some streams were even sampled monthly for a few years—not always the same years, but I’ve included some monthly averages to show the seasonal pattern.

May 2019 SnapshotBluestem CreekCollege CreekPrairie CreekSquaw Creek @Duff Ave
Cropland in watershed90%19%82%81%
Nitrate5 mg/L2 mg/L5 mg/L5 mg/L
Phosphorus0.8 mg/L0.2 mg/L0.3 mg/L0.2 mg/L
E. coliNot sampled1,220 CFU/100mL11,700 CFU/100mL9,600 CFU/100mL

College Creek is almost entirely within the city of Ames.  Urban streams have their own set of water quality challenges.  Road salt applied in winter can lead to elevated levels of chloride. E. coli levels used to be very high due to issues with septic systems.  Paved surfaces mean more runoff after heavy rains, carrying contaminants and worsening bank erosion.  (A 2019 Water Quality Improvement project to install permeable pavement and tree trenches on Welch Ave will help reduce runoff to College Creek).

But despite all the athletic fields and residential lawns in the watershed, College Creek typically has lower nitrate levels than rural tributaries.  If you’ve seen your neighbor over-fertilize their lawn and are wondering why that doesn’t have more of an impact, it’s worth remembering that turfgrass is a perennial and, like a good cover crop, is actively growing and taking up nutrients in April and May when most fields are bare.

Bluestem Creek is located in rural Boone County.  It is usual in that it has no nearby hog barns, and presumably no hog manure applied in the watershed.  It contributes plenty of nitrogen to Squaw Creek but appears to have lower phosphorus levels than Prairie Creek, another rural tributary with at least two hog confinements in its watershed.  Hog manure is a good fertilizer (adding nitrogen, phosphorus, and organic matter to the fields where it is applied) but farmers don’t always account for it when applying commercial fertilizer.

Bluestem Creek does have cows, which entered the water for 5 minutes while I was doing water testing this spring.  I have a soft spot for cows because their presence on the landscape can make cover crops and more diverse crop rotations financially viable.  I’d rather see pasture along the creeks than have it plowed right up to the edge.  But it’s true that cows can stir up sediment and poop in the water if they have access to the creek.  I’ve heard feedlot owners complain that they have to fill out a lot of paperwork regarding their manure management and receive a lot of scrutiny from their neighbors, while smaller livestock producers are not held to the same standard.

Ultimately, I think stream monitoring data shows that we all have a role to play in improving water quality, whether that’s reducing runoff and erosion in urban streams through rain gardens and permeable pavement, improving soil health with cover crops and no-till, better management of manure and fertilizer, or removing nitrogen from drainage water with bioreactors and saturated buffers.

Watershed Matchup #2: Clear Creek VS Clear Creek

This post is part of a series for 2019 Watershed Awareness Month, comparing water quality in a pair of local creeks to learn how land and people influence water.

Clear Creek @Hyland on May 18Clear Creek@ Hyland on May 24
Transparency > 60 cmTransparency of 1 cm
Orthophosphate 0.1 mg/LOrthophosphate 5 mg/L

Clear Creek was true to its name on May 18 when the Squaw Creek Watershed Coalition did its spring water quality snapshot.  Long-time member Ed Engle and three Ames High School students (Wil, Becca, and Nate) filled a transparency tube to the top (60 cm) and the secchi disk at the bottom was clearly visible.  A week later, Rick Dietz tested the same location after a 1.7 inch rainstorm and couldn’t see the disk until he’d poured out all but 1 cm of the water!

Phosphorus in Clear Creek was high enough we had to break out the high range comparison vials!

Water quality can change rapidly.  Sediment* in the water spikes during and after a big rain storm.  So does phosphorus and E. coli.  Nitrate and chloride show strong seasonal patterns.  While some of that variation may average out in a big dataset, when streams are sampled less often, it can be tricky to make an apples-to-apples comparison.  That’s why water quality snapshots—multiple streams sampled on the same day—are so valuable.

*measured as clarity, turbidity, or total suspended solids

The Coalition has been monitoring Clear Creek since 2007.  It normally has pretty good water quality, with orthophosphate near the outlet averaging 0.2 mg/L and transparency averaging 43 cm.  23% of the riparian area is forested (Pammel Woods, Munn Woods, and Emma McCarthy Lee Park) so that’s part of the reason.  Another reason is the efforts of some farmers in the watershed.  Jeremy Gustafson has been improving his soil and protecting water through his innovative use of cover crops–planting soybeans into living rye and using diverse mixes after oats.

Farmer Jeremy Gustafson shows members of the Squaw Creek Watershed Management board how cover crops have improved his soil.


Still, there’s room for improvement.  Nitrate levels average 5.7 mg/L in Pammel Woods, and 7.5 mg/L at the Boone-Story county line.  (For reference, nitrate was historically less than 2 mg/L). And as the “gully washer” of May 24 shows, the relatively flat “Des Moines Lobe” region of Iowa is not immune to soil erosion!  More no-till, cover crops, and prairie strips could further reduce erosion.  More sediment ponds, wetlands, and buffers could prevent sediment from reaching the creek.

A creek sign on the Lincoln Heritage Byway (Ontario Rd near the county line)! You can’t get more Prairie Rivers of Iowa than that!  The creek was out of its banks.

Clear Creek, College Creek, and Worrell Creek all start in Boone County and join Squaw Creek in Ames.  We’ll continue to support conservation practices in these watersheds through our Small Landowner Assistance project (wrapping up this year) and our National Fish and Wildlife Foundation grant (just getting going).  If you live or farm west of Ames and are thinking about conservation, or know someone who does, give us a call!