by | Mar 14, 2022

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Legacy Sediment for Fourth Graders

Legacy Sediment for Fourth Graders

by | Feb 28, 2022

For Iowa History Month, I’d like to talk about legacy sediment—historic erosion that has a big influence on sediment, phosphorus, and fisheries in rivers today.  For a change of pace, this article is written at the fourth-grade reading level.  I like big words like “fluvial geomorphology” but not everyone does.  Okay!  Let’s have some fun learning!

The faster the water moves, the more stuff it can carry. Fast-moving water washes away the tiny stones (sand and silt).  It leaves behind the bigger stones (gravel). Slower moving water washes away the silt but leaves behind the sand.  If a beaver or a person dams up the water and it really slows down, even the silt settles out. That’s why mountain streams have rocky bottoms but lowland streams have muddy bottoms. It’s also why there are sand bars on the inside of river bends where the water moves more slowly.

Photo by Dan Haug. Note the transition from silt to sand to gravel to rocks going left to right from slower to faster water.

Plants’ roots and leaves can keep dirt from washing away, and so do the tiny things that live on plant roots. They actually make a glue that holds the dirt together!  There’s been a few times when dirt and rocks moved a lot faster than normal because there weren’t any plants growing. Twelve thousand years ago, there weren’t any plants in my part of Iowa because the land was covered in a big sheet of melting ice. It happened again 190 years ago when farmers started moving in and plowing up the grass to grow crops. The ground was bare for most of the year, so dirt washed off the hills and filled up the valleys. 90 years ago, farmers realized this was a problem and got more careful about how they plowed. But then 50 years ago some of them forgot and weren’t as careful.  But they remembered again, so it’s better now. (Read more about this history here)

Figure adapted from Beck et al. 2018. Photo by Hanna McBrearty.

There’s still lots of soft mud in the valleys from those days.  That’s a problem because the water moves a lot faster now. Partly that’s because there’s more pavement and fewer marshes. Partly that’s because people straightened out some of the curves in the rivers. The fast water hits the soft mud and makes little canyons all over Iowa. The water can’t get out of the canyons unless there’s a really big flood so it almost never slows down. The canyons are not as pretty as the Grand Canyon and the fish don’t like them as much. The soft mud in the river valleys also has fertilizer in it that can make the water turn green. The fish don’t like that either.

Photo by Dan Haug. Steep bank in Ioway Creek in Ames.

If you like fish and want the ugly canyons to turn into normal-looking rivers you have two choices.

1. You can stop dumping concrete on the river banks and wait. The water will keep washing away dirt on the outside of the river bend. That makes the valley wider. Some day, the bank will cave in. That will make the valley less steep. Some houses and bridges might fall into the river too. That would be exciting!

2. You can use a backhoe to move the dirt around so the valley isn’t as steep and narrow. I like that idea better.  It would also be a good idea to have trees and grass near the river to hold the dirt together.

Photo by Dan Haug. The stream at the Tedesco Environmental Learning Corridor doesn’t look like a canyon anymore because the county brought in a backhoe to restore it.

If you like reading about science and engineering with very small words, I recommend a funny book called Thing Explainer by Randall Munroe.

If you want to learn the big words too, then I think you should listen to Jeff Kospaska at the Iowa Department of Natural Resources, Tom Isenhart at Iowa State University, or Billy Beck at ISU Extension.  I learned a lot from them!

The Impaired Waters List is a Missed Opportunity

The Impaired Waters List is a Missed Opportunity

by | Feb 21, 2022

Many Iowans would like to know which lakes and rivers are safe for recreation and good for fishing because that affects how they’ll engage with the outdoors. They would like to know whether water quality is improving, and if not, what kinds of changes on the land would make a difference. Regardless of whether you think the right way to improve water quality is through voluntary projects, legislation, or some combination, we need good information to guide our efforts. However, for all the attention it gets, the 2022 Impaired Waters List does not really tell us which waters are safe for recreation or the direction of statewide trends. We think that’s a missed opportunity.

By the Iowa Department of Natural Resources (IDNR) own admission:

“An increase or decrease in impaired waters does not necessarily mean that the water quality in the state is worsening or improving. It could be a reflection of the additional monitoring we are conducting, changes in water quality standards, and changes in assessment methodologies. Impaired segments are often used for recreation and fishing, among other uses, so impairment doesn’t mean that the segments are unusable.”

-Roger Bruner, Supervisor, Water Quality Monitoring and Assessment section, IDNR

While there’s a lot of good science that goes into Iowa’s water quality assessment database, the list of impaired waters is not a scientific study of water quality status and trends. (The United States Geological Survey actually does that through a national program you’ve probably never heard of). 303(d) lists are legal documents written by state natural resource agencies for the Environmental Protection Agency, as required by Section 303(d) of the Clean Water Act. Even if the IDNR wanted to make things clearer for the public, many of the terms and categories are defined by federal rules and linked to other regulatory processes.

In other words, the Impaired Waters List is part of a Rube Goldberg machine! If you’d like to comment on the draft list before March 19 — either to ask questions about particular water bodies or to express your opinion on Iowa’s larger approach to water quality — you may benefit from the following explanation of the machine.

Disclaimer: I am not an environmental lawyer or policy expert, and am probably not treating the subject with the seriousness it deserves wink.

I don’t mean to throw shade on the staff at environmental agencies or the Clean Water Act. The 1972 law is the reason why American rivers mostly don’t burst into flames anymore. Some lakes and rivers in Iowa have benefited from the process described above, which results in technical information, stakeholder engagement, and grant funds that can help improve water quality. One example I’m familiar with is Hickory Grove Lake in Story County, which is now on its way to recovery. However, many other water bodies have gotten stuck somewhere in the process. I’ll share some examples from Central Iowa.

Step One: If the water was clean, could you swim or fish in it?

The goal of the Clean Water Act was for our waters to be swimmable and fishable by 1983 (yes, we missed that deadline). “Designated uses” for each lake and stream segment clarify what kind of recreation or aquatic life is possible, and these affect which water quality criteria are applied. For example, the Iowa River at Eldora has plenty of water for fishing, swimming, and paddling (so is designated A1 B-WW1). The South Skunk River at its headwaters near Blairsburg is too shallow for any of these uses, regardless of water quality (so is designated A2 B-WW2). As a result of this difference in designated uses, the Eldora Wastewater Treatment Plant must meet stricter E. coli and ammonia limits than the Blairsburg Sewage Treatment Plant.

However, perhaps one-half of the waters in the database have an asterisk next to the designated use. Most smaller creeks in Iowa are presumed to support primary contact recreation until the IDNR determines otherwise, through on-site investigation and surveys of residents. For example, Long Dick Creek in Hamilton County does not have enough water to float a canoe, but since no permit is affected by this determination, Iowa DNR has never been asked to find out. If they did a use attainability analysis, Long Dick Creek would probably not be on the Impaired Waters List — it has E. coli levels exceeding the primary contact standard, but below the secondary contact standard. For this creek, both the impairment and the protections provided by the Clean Water Act are hypothetical.

When a use attainability analysis is done, the conclusions can be confusing. I had understood secondary contact recreation to mean “shore-fishing” but is often paired with a designated use for aquatic life that implies there are no fish worth catching. I had understood primary contact recreation to mean “deep enough for canoeing”, but IDNR uses it to mean “deep enough to accidentally go swimming if you tip your canoe”.

Step 2: How clean does the water need to be for fishing and swimming?

Here’s an example of how the factual questions about the condition of Iowa’s waters get tangled up in economic and legal questions about how to address it. We know that algae blooms can kill fish and become a nuisance (or a safety issue) for swimmers and boaters. We know that phosphorus and nitrogen contribute to algae blooms in Iowa waters. We have lots of data about nitrogen and phosphorus in Iowa waters. We even had a study by IDNR staff examining the relationship between nutrients and aquatic life. What we still don’t have is numeric criteria to translate nitrogen and phosphorus data into “fully supporting”, “partially supporting” or “not supporting” for fishing and recreational uses of lakes and rivers.

Why? Because water quality criteria are not just used to make sense of the data; they are also used to regulate wastewater treatment plants. Iowa’s Environmental Protection Commission has rejected calls to establish numeric nutrient criteria because they were concerned it would put too heavy a cost on municipalities. It’s a valid concern — one that other states have dealt with through permit variances and nutrient trading systems.

Step 3: Is the water clean enough for fishing or swimming?

Assessments are done every two years using recent (but not current) data. The 2022 cycle uses data from 2016 to 2020.

Don’t expect a comprehensive list. Iowa has many lakes and streams and Iowa DNR does not have the resources to monitor them all. Almost one-half of the waters (49% of the river segments, 48% of lakes and reservoirs, and 18% of wetlands in the database) were not assessed for the 2022 cycle.

Even this is overstating how much we know. Most waters are assigned a designated use reflecting what kind of recreation is possible (Class A) and what kind of aquatic life is possible (Class B). The IDNR has conclusive enough data to say whether or not aquatic life uses are supported for 21% of river segments and 33% of lakes and wetlands. IDNR has conclusive enough data to say whether Recreational Uses are supported for 19% of river segments and 57% of lakes and wetlands.

Step 4: Oh no, the water is too dirty for fishing or swimming!

Local groups are doing water quality monitoring and could help the IDNR assess more water bodies. For example, Prairie Rivers of Iowa and our partners documented E. coli levels in Ioway Creek that were 18 times higher* than the standard! However, since our data was not collected under an IDNR-approved quality assurance plan (and since IDNR rarely approves such plans), the most they can do is put Ioway Creek on a list of “Waters in Need of Further Investigation” (WINOFI). If not for a state law (the Credible Data Law), the Impaired Waters List might be much longer and more worrisome.

*The South Skunk River between Story City and Ames is still on the Impaired Waters List because in 2014, the average (in this case, a geometric mean) E. coli count for the season was 223 colonies per 100mL, almost twice the primary recreation standard (126 colonies/100mL). In Ioway Creek in Ames, Prairie Rivers and our partners documented an E. coli geometric mean of 2,280 colonies/100mL in 2018.

Step 5: How can we clean up the water?

The 303(d) list is not just an embarrassment for the state of Iowa. It’s also a waiting list for a water quality improvement plan. These plans are time-consuming to write, so the IDNR has to prioritize. Bacteria impairments in rivers are considered a lower priority, so the South Skunk River between Story City and Ames has been on the waiting list since 2004. It’s in good company: there are 594 stream segments, lakes, and wetlands that need a Total Maximum Daily Load (TMDL).

Step 6: Let’s clean up the water!

Some lakes and rivers have water quality improvement plans that were written over a decade ago and haven’t been implemented. I’ve read a few. In the case of the Little Wall Lake plan (2005), the report did not offer any good solutions, and maybe there aren’t any–it’s a shallow lake with a lot of phosphorus in the muck that gets stirred up when it’s windy. In the case of the Raccoon River plan (2008), solutions are recommended, but there are many obstacles to implementing them: both social (many farmers don’t want to) and legal (the Clean Water Act can’t make them).

How to get involved

You can comment on the Draft Impaired Waters List through March 19, 2022, by mailing a letter to:

Iowa Department of Natural Resources
Attention: IR Comments
Water Quality Monitoring & Assessment Section
Wallace State Office Building
502 East 9th Street
Des Moines, IA 50319

Or send an email to: IRcomment@dnr.iowa.gov.

As I’ve said, we think the Impaired Waters List represents a missed opportunity to communicate with the public about threats and opportunities to recreation and fisheries in Iowa waters. We would welcome a discussion about how this gap could be filled.

Making Sense of Water Quality Data – A Paddler’s View

Making Sense of Water Quality Data – A Paddler’s View

by | Jan 31, 2022

Later this month, we are releasing a report with the findings from Story County’s 2021 water monitoring season.

In some ways, 2021 was an unlucky year to launch a water quality monitoring program. Story County was in drought conditions for much of the year, and smaller streams were frequently dry when we did our monitoring routes.

In some ways, it was an ideal year to launch a monitoring program, because weather always has an influence of water quality and the challenging conditions in 2021 forced us to better account for it. 

For the report, this means asking a simple question: “was there enough water to float a canoe on the day you sampled?”

Iowa's first African American female mayor LaMetta Wynn being sworn in on January 3, 1996 as mayor of Clinton, Iowa.

When the South Skunk River is too low for paddling:

  • Not much water (and not much nitrogen and phosphorus) reaches the Gulf
  • “Hot spots” for nitrogen and phosphorus are below wastewater treatment plants
Nitrate levels during conditions suitable for paddling.

When the South Skunk River rises high enough for paddling:

  • “Hot spots” for nitrogen are in the Headwaters of the South Skunk River Watershed upstream of Ames, as shown in the graph
  • E. coli levels upstream of Ames (and Ioway Creek) get worse but still meet the standard
  • E. coli levels downstream of Ames (and Ioway Creek) get better, but still exceed the standard

If I had less curiosity and more sense, I would have written a short report:  “great job everyone!  We collected a lot of data.  Here it is! It’s possible that drought had an influence on water quality.”  This was more work, but I hope you get more out of it.

Are small towns a big problem for water quality?

Are small towns a big problem for water quality?

by | Dec 17, 2021

Before state wastewater standards went into effect in the 1960s, raw sewage could flow directly to a stream without treatment. Despite the standards, this continues in many areas today. In areas called “unsewered communities,” outdated or poorly functioning septic tanks still allow untreated wastewater into our waters.  The Iowa DNR works with these communities to find funding sources and alternative treatment systems and to allow adequate time to upgrade the systems.

Iowa DNR: Rural Community Sewers

The Governor has announced that additional funding through the infrastructure bill that will be available to help unsewered communities upgrade their systems.  Could this make a big difference for water quality in Iowa?  Statewide, I’m not sure, but I’ve taken a closer look at the Iowa River Basin upstream of Marshalltown, where we know of 11 unsewered communities.  Based on my first look at the data, it appears that these communities have little influence on E. coli in the Iowa River itself, but could make a difference for water quality in tributary streams like Beaver Creek in Hardin County.

There are 11 unsewered communities in the upper part of the Iowa River Basin, marked here with yellow circles with an X.

A Water Quality Improvement Plan for E. coli bacteria in the Iowa River Basin was released by Iowa DNR in 2017.  As required by the Clean Water Act, these kinds of plans include a Total Maximum Daily Load (TMDL) of pollutants that a water body could handle and still meet water quality standards.  Author James Hallmark compares this pollution budget to a family budget: regulated point sources are your fixed bills, non-point sources are your variable expenses, and the margin of safety is your emergency fund.  I like this analogy and would add that without some understanding of where your discretionary spending is going, and a realistic strategy to reign it in, you’re probably not going to achieve your goals.

The Water Quality Improvement Plan includes a comprehensive list of E. coli sources but doesn’t single any of them out as being particularly important.  It includes a list of potential solutions, but it doesn’t identify which of those would make the most difference.  That’s a job for a Watershed Management Plan written with stakeholder input, apparently. However, the document is chock-full of load-duration curves, which I wrote about previously.  We can use the information in these charts and tables to take the next step and begin to narrow down where and when the pollution is most serious!

In this article, I won’t pay much attention to “High Flows” and “Low Flows” because there wouldn’t be much recreational use under these conditions. I also don’t look at “mid-range” flows because there’s a bigger mix of sources influencing water quality in these conditions. A closer look at the other two categories is revealing.

common sources of bacteria for different flow conditions

If houses are discharging raw sewage directly into a stream, we’d expect to see the highest E. coli concentrations when the stream is running lower than normal, and there’s less dilution.  This is indeed what we see in Beaver Creek in Hardin County, which is downstream from the unsewered community of Owasa.  Beaver Creek would need a 79% reduction in E. coli load to meet the primary contact recreation standard during “Dry Conditions” and a 38% reduction during “Wet Conditions”.

If not fully treated, sewage could be a major contributor to E. coli in some tributaries of the Iowa River.

Treated sewage also has the biggest influence when streams are lower than usual.  The upper reaches of the South Fork receive effluent from the small towns of Williams and Alden, which have waste stabilization lagoons.  It’s likely that some bacteria makes it through the treatment process, and this would explain why E. coli is higher during “Dry Conditions” (needing a 73% reduction) than during “Wet Conditions” (needing a 30% reduction).  When their permits come up for renewal, Iowa DNR could require a UV disinfection system to ensure that E. coli in effluent is no greater than 126 colonies/100mL.

The blue line is the wasteload allocation–the regulated part of the pollution budget. Even with the best available treatment, wastewater from two towns has a big influence on the South Fork during dry conditions.

In a watershed with few people and many hogs, we’d expect to see the highest E. coli concentrations when the streams are running high and runoff from fields that receive manure application is more likely.  This is indeed what we see in Tipton Creek in Hardin County, a watershed containing 47(!) CAFOs, but the levels are not especially high compared to other sites in the Iowa River basin.  The recreation standard is met during “Dry Conditions” and would need a 36% reduction during “Wet Conditions.”  Handled correctly (applied to flat ground at the right time, and preferably incorporated into the soil), manure and the microbes it contains can be kept out of streams.  Preventing loss of the nutrients in manure is a more difficult challenge—nitrate concentrations in Tipton Creek often exceed 20 mg/L!

Despite there being a lot of hogs in the Tipton Creek watershed, E. coli levels are not especially high, relative to downstream locations.

It’s not clear to me whether primary contact recreational use of these streams is a relevant or attainable goal, or whether we should be calibrating our level of concern to the secondary contact recreation criteria. Unless there’s a permit holder affected, IDNR doesn’t investigate whether there’s enough water for kayaking in Tipton Creek, or whether children play in Beaver Creek, so the designated use is presumptive and tells me nothing.

E. coli and recreation on the Iowa River is not as big a concern at Crystal Lake as it is at Steamboat Rock.
Photo Credits: Ryan Adams, photojournalist

To protect fishing, paddling, and children’s play on the Iowa River itself, where and when should we focus?  The Iowa River at Marshalltown needs a 60% reduction in bacteria load to meet the recreation standard during “Wet Conditions” (10-40% flow exceedance).  However, it actually meets the primary contact recreation standard during “Dry Conditions” (60-90% flow exceedance).  Focusing on unsewered communities in the watershed would NOT be an effective way to address this impairment.

Beaver Creek (left) has worse E. coli when it’s dry. The Iowa River near Marshalltown (right) has worse E. coli when it’s wet. If the green line is above the red line, that indicates that the E. coli geometric mean for that range of flows exceeds the standard.

Galls Creek in Hancock County has some of the worst E. coli levels measured in the basin, and would have a larger per-acre benefit to the Iowa River if standards could be met.  Galls Creek has no unsewered communities but at least 20 farmsteads located along the creek that could have issues with septic systems overflowing under wet weather.  The watershed has little woodland and no pasture, so land application of manure from the several CAFOs in the watershed would be most likely animal source of E. coli.

Table by Prairie Rivers of Iowa, using information from the Water Quality Improvement Plan for the Iowa River Basin

This is just a partial review of one of three HUC8s in the Iowa River Basin. There is much more to learn from further discussion with people who know the area well, or from on-site investigation.  However, I hope I’ve demonstrated how we might squeeze some more insight out of the data we have, in order to make smart investments in water quality.