2018 Impaired Waters List

The Iowa Department of Natural Resources is seeking public comment on the newly released draft impaired waters list.  Prairie Rivers of Iowa will be recommending that Squaw Creek and East Indian Creek be added to “Waters in Need of Further Investigation.”  We’ll also take this opportunity to try to demystify a topic that can be confusing, using examples from the South Skunk River watershed.

Every two years, the DNR is required to assess the available data to determine whether Iowa’s lakes, rivers, and wetlands are meeting their designated uses.  About half the rivers, and a bit more of the lakes have enough data to assess.  Since new waters are considered each cycle, the length of the impaired waters list doesn’t really tell us whether water quality is getting worse.  Since nutrients aren’t considered for most uses and the data used for the 2018 assessment is from 2014-2016, it doesn’t tell us whether the Iowa Nutrient Reduction Strategy is working.  What it tells us is the extent and severity of local water quality problems that have been officially vetted.

Recreational Uses

A river segment, lake, or reservoir that gets use by paddlers or where children play would be designated A1 (primary contact recreation use) or A3 (children’s recreational use).  To determine whether the water quality is good enough to support these uses, the DNR compares E. coli bacteria to the state standard (a geometric mean of 126 organisms per 100mL).  If the stream consistently exceeds the standard, that means there could be enough human or animal waste in the water to pose a health risk to anyone that swallowed some–a child splashing in the creek, or a paddler who tipped their canoe might get exposed to a waterborne illness.

Fully supporting:  None of the lakes or rivers in our watershed appeared on this list

Partially supporting: The South Skunk River above Ames was slightly impaired with high E. coli levels in one of three years.  Indian Creek near Maxwell, the upper part of Long Dick Creek in Hamilton County, Montgomery Creek in Boone County, Hickory Grove Lake in Story County, Lake Keomah and White Oak Lake in Mahaska County all have moderate E. coli problems.

Not supporting:  Prairie Creek in Boone County has consistently high E. coli levels.  The data was collected through an agreement between Iowa DNR and volunteers with the Squaw Creek Watershed Coalition.

Not assessed:  This includes Squaw Creek, East Indian Creek, McFarland Pond, and many others.

Wait a minute, Squaw Creek and East Indian Creek?  Didn’t we work with City of Ames and Story County Conservation to collect three years of monthly E. coli samples, starting during the assessment period?  Wasn’t the 2016 geometric mean ten times higher than the standard? Yes, but DNR never approved a quality assurance plan, so under Iowa’s Credible Data Law, they can’t use our data.  However, we will write to DNR to recommend that they add those streams to Iowa’s list of waters in need of further investigation (WINOFI).  We’re aware that bacteria cleanup plans for large rivers are difficult to do and are a low priority for the department, but we want people to be more aware of the health risks.

Aquatic Life Uses

The South Skunk River is  a warm water stream with a smallmouth bass fishery, so is designated B(WW-1).  Most of its perennial tributaries don’t have enough water or habitat for gamefish so are designated* B(WW-2) for other aquatic life.  Fish kill reports, biological monitoring of fish and invertebrates, and monitoring of dissolved oxygen and some toxic chemicals are used to assess whether water quality is good enough to support these uses.

*Adding to the confusion, smaller creeks are given a presumptive A1 B(WW-1) designation until a Use Attainability Assessment proves otherwise.  This change supposedly gives them extra protection, but I don’t see how that would work in practice.

Fully supporting: A lower segment of the South Skunk River in Mahaska County, Little Wall Lake, Hickory Grove Lake, lower Squaw Creek, and Montgomery Creek appear to have good enough water quality for a healthy aquatic community.  FYI: Fish aren’t bothered by high nitrate or E. coli.

Partially supporting:  The South Skunk River above Amesthe upper part of Squaw Creek, Long Dick Creek, upper Ballard Creek, and Walnut Creek are on the impaired waters list due to fish kills or a low quality fish or invertebrate community.

Waters in Need of Further Investigation:  Onion Creek, Worrell Creek, and College Creek had some low scores for fish or invertebrates, but DNR hasn’t worked out an appropriate threshold for these headwater creeks.  The lower part of Ballard Creek was removed from the impaired waters list and placed in this category when DNR discovered an error in the previous assessment.

Not Assessed: This includes several segments of the South Skunk River, Dye Creek, Clear Creek, Keigley Branch, West Indian Creek and many others.

Takeway message:

If a river was added to the impaired waters list, don’t assume it’s gotten dirtier.  Maybe it was always polluted and we hadn’t bothered to look.  And by the same token, if a river is not on the impaired waters list, don’t assume it’s clean.

 

Watershed Matchup #4: Upper Squaw Creek vs. Lower Squaw 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.

On May 20, the Skunk River Paddlers launched their canoes and kayaks on Squaw Creek at 100th Street in Hamilton County and paddled down to 140th St in Boone County.  The recent rains made it a fast ride!

However, the rain also washed a lot of sediment and quite likely some land-applied manure into the stream.  I collected a water sample just before I took this photo and had a lab test it for E. coli bacteria, an indicator of fecal contamination: 2,390 CFU (Colony Forming Units)/100mL.  That’s 10 times the primary contact standard for a single sample (235 CFU/100mL) and just shy of the secondary contact standard (2880 CFU/100mL).

Later that day, I collected a sample from Brookside Park in Ames with the help of my son.  The lab results came back at 12,800 CFU/100mL, well above the secondary contact standard!

I don’t want to discourage people from recreating in Squaw Creek but I think a safety reminder is necessary:

Squaw Creek has consistent fecal contamination that could pose a risk of acquiring a waterborne illness.  The risk is higher after heavy rains when the water is muddy—consider wearing waterproof boots when wading under these conditions.  If you come into contact with the water, wash your hands or apply hand sanitizer before eating and take precautions to avoid getting river water in your mouth or on an open cut.

The numbers above are high, but not unprecedented.  Over the past three years, City of Ames staff have been tracking E. coli, nitrogen, and phosphorus in Squaw Creek at Lincoln Way and we’ve been sharing the data on our website.  46 out of 48 samples exceeded the primary contact standard for E. coli!

Yes. Yes there is.

The pattern is also not unusual.  In our Snapshots, we see that Squaw Creek usually exceeds the standard by the time it reaches Ames and picks up additional fecal contamination by the time it reaches Duff Ave.

The Ames City Council, Public Works Department, and Water & Pollution Control Department are concerned by the data and committed to helping find and address sources of contamination within city limits.  The City of Ames spends $3.5 million a year repairing and upgrading its sanitary sewers.  However, the data point to multiple sources of E. coli that will make this a difficult problem to solve.  In addition to sewer leaks, we probably have some failing septic systems in the upper watershed, cattle in the stream, land-applied manure carried by runoff, pet waste, and wildlife.  E. coli can also persist for a while in the sediment, and gets stirred up again after a rain.

In June, I went back to Brookside Park to demonstrate some water quality testing for kids enrolled in the Community Academy summer program.   In addition to exploring nature and food systems, the kids have been hard at work improving removing invasive species, planting pollinator gardens, improving trails, and coming up with interpretive signs for Brookside Park.  I’m pleased to see that one of the signs is about water quality, including a reminder to wash your hands after entering the creek, and tips on how to reduce pollution.  Look for the signs to go up later this summer.

My son Leif shares a draft of a water quality sign at the Community Academy’s open house