Clean-Water Factory (with ducks…)

dsc_0369Before visiting an area on this 99wetlands quest, I sometimes read a technical note or scientific journal article to provide some context. Before visiting Kiowa Marsh in Sac County, I found a 1917 study in the Wilson Bulletin by J.A. Spurrell, described the condition of the County before settlement by Whites. The eastern half of Sac County had been covered by the Des Moines Lobe, a giant glacial surface coming down from Minnesota, the Dakotas, and Canada, and looking like a giant tongue. In eastern Sac County it formed a classic pothole landscape, prairie dimpled with shallow water features and wetlands. To quote the article,

“Correction pond, Lard lake, Rush lake, and many smaller ponds are now farm land.  …The drainage from Wall lake, the only one remaining, flows into Indian Creek.”

dsc_0371And this is where we have good news: a large wetland restoration at Kiowa Marsh, part of the Indian Creek watershed. The marsh is owned by the Iowa Department of Natural Resources, but the restoration was a cooperation withUS Fish & Wildlife Service, and Ducks Unlimited and used funds from the Environmental Protection Agency. That link takes you to an article, and yet other than the headline, only a passing mention of wildlife is made. However, statistics about the wetland and water quality are provided:

  • Indian Creek is part of drainage leading to the Raccoon River…which provides critical drinking water for more than 450,000 Iowans—or roughly one-sixth of the state’s entire population
  • ditches that empty into the marsh…drainages have for years served as a superhighway for soil particles and nutrient runoff that enter Kiowa Marsh and eventually flow into downstream creeks, rivers and reservoirs.
  • the restored wetlands will reduce sediment delivery to Indian Creek by approximately 652 tons/year and will help trap and recycle an estimated 847 tons of phosphorus per year
  • total cost of these restoration efforts was nearly $300,000 and will pay back significant dividends to Des Moines area water users
  • …and so, once again we face the clear truth. Yes, these wetlands WILL provide valuable habitat to waterfowl (and thereby, to hunters or birders). But the reasons wetlands are protected under the Clean Water Act, or the reason this particular wetland was restored using monies from the EPA, is that—whether they provide for the classic wildlife triumvirate of “Fur, Fins & Feathers,”—they first and foremost are about the water. No wetland is ever “isolated.” Our wetlands work to clean our water.

dsc_0365In correspondence with Clint from the DNR, he mentioned the considerable work in making sure that drainage from neighbors is properly incorporated, and that water storage and movement in the wetlands can be adjusted to attain project goals. Additional work on the north basin was in progress during my visit; this hard-working wetland will have even more benefits very soon.

The great thing is, in restoring wetlands for water quality benefits, we also support habitat for wildlife. A sign at Kiowa refers to the Waterfowl Production Area…AKA “duck factory.” That’s in addition to the restoration funding having the stated goal of being…a clean water factory!

Come back next week as I “connect the dots” of water quality in these three recently-profiled counties, and think about the recent news reports and legal action involving Iowa water quality, and the considerable work we still have to do. And I may have a suggestion to help with all this (spoiler: it involves wetlands!!). See you then.dsc_0363


The Wetland as Traffic Cop

entrance near the south end of the marsh, along Hwy 110. Note the wood duck housing complex.

Last week, we visited the Twin Lakes in Calhoun County. We saw how a wetland adjacent to South Twin Lake sits at the base of a slope, catching silt, sediments, nutrients, and other substances in runoff. Wetlands naturally “clean the water,” as we have discussed many times. This week, let’s expand that idea a bit.

Little Storm Lake in Buena Vista county is not really a lake at all: it is a wetland adjacent to the northwest edge of Storm Lake, an actual (shallow glacial) lake. It’s a great place to think about a wetland “cleaning the water.”

In my Limnology class, I sometimes ask students to think of a lake as a giant container of water in which chemical reactions happen. Much like the glassware holding aqueous (watery) solutions in their chemistry classes, a lake will be affected by light and heat energy, circulation (that is, mixing), atmospheric pressure, and other inputs to the system from outside. Reactions in the water will depend on pH, dissolved gasses, and the activity of organisms. Particular chemical reactions all occur (or not) in that context. This “lake as a big glass beaker” mental image is then kept in mind as we discuss specific chemical parameters and reactions.

access road leads in to water control structures, and forms a berm or dike

Then again, a wetland (like Little Storm Lake) is perhaps like a chemist, adjusting the characteristics of water entering the lake. It’s often said that a wetland “cleans the water,” but truly a wetland transforms chemicals in the water in ways we categorize as “cleansing.” For example, silts and sediments settle out of the muddy water, depositing (and slowly filling) the wetland; the water leaves the wetland “cleaner.” Phosphorus sorbs (adheres to) the silts and sediments, and so are removed from the water as well. Nitrogen is transferred from water to air, by an entirely different process—denitrification—and we’ll consider that next week. These are all examples of the “wetland as chemist.”

Little Storm Lake is a natural marsh, but it was recently extensively modified to move beyond that role as “chemist,” into a role as “Traffic Cop.” Much like a public safety officer directing vehicles safely and efficiently on roadways, this wetland is now equipped to direct the flow of water safely and efficiently. Let’s have a look!

dueling water control gates

About eight years ago, the DNR partnered with the local lake association, non-profit groups, university staff and others to undertake a large wetland restoration (more correctly, engineering enhancement) and lake protection project. This Storm Lake page describes the project, and a DNR lake restoration white paper has more details (starting on page 17). The basic idea is this: construct walls (dikes), and channels or culverts (plumbing) store and move water as desired; they prohibit fish movement (ideally, keeping nuisance species like carp under control); and workers periodically dredge out the accumulating silts and sediments.

If a wetland like Little Storm Lake exemplifies the slogan “Better Living Through Chemistry” by the transformations cleaning the water, then this project now adds “Better Living Through Plumbing.” Water in this wetland can be adjusted to appropriately process high flows, normal flows, or even to drain the system of water. Drying out a wetland seems counterproductive, but an occasional decrease in water depth and even emptying (“drawdown”) encourages seed germination, facilitates maintenance, and kills off undesirable aquatic species. If the wetland (and adjacent lake) function is determined mainly through water dynamics, then this project provides a powerful tool.

Probably a pumping station, although it also reminds me of a nuclear reactor. Cordoned off, so I couldn’t examine it well enough to know which.

Furthermore…let’s be honest: Iowa’s streams and rivers, such as the one flowing into this wetland (Powell Creek), carry a heavy load of runoff…and everything runoff brings. Wetlands are helpful—perhaps critical—in protecting our water quality. It’s a theme we’re considering in these weeks, with wetlands from three counties and an upcoming essay considering the challenge we face regarding Nitrogen in particular. I wish to address the news reports and controversy, and ask if wetlands might just help us solve the problem. Please come back in the coming weeks for that discussion.

In the meantime, if you’re near Storm Lake, check out the marsh. On the north side, near the intersection of state highways 7 and 110, you’ll find the Little Lake Discovery Boardwalk. Informational signs adorn a floating walkway among the cattail, and a tall tower provides a stunning view (complete with free telescope!). Admire the flora and fauna and another hard-working wetland…”at your service.”



“Pond,” “Lake,” or “Wetland…?” Whatever.

Pretty houses and cottages along North Twin Lake. A State Park with pavilion and restrooms is nearby, but no camping is available.

The Twin Lakes (North and South) of Calhoun County are a good example of the old question, “what’s in a name?” As a Limnologist–someone who studies water bodies on the continents: ponds, lakes, rivers, streams…and of course, wetlands!—I am sometimes asked how to differentiate between these systems. People want to know for example, when does a pond have sufficient surface area, or depth (or both?) to properly be called a lake?

For better or worse, there IS NO “official” distinction between these terms. (Really!) Suggestions involving the photic zone depth, or stratification, or minimum area…they are all attempts to be helpful, but are nevertheless always arbitrary. Here, someone decided that (likely in consideration of surface area), the Twin Lakes are each truly “lakes,” and of course the name reflects that. According to the Iowa DNR, North Twin Lake is deeper (ranging in parts to 12 feet/3.7 meters), while South Twin Lake is mostly between four and five feet (1.2-1.5 m) deep. South Lake is about a third larger in surface area, however (600 vs 453 acres/243 vs 183 hectares). In this part of the world, those are large enough to be considered lakes, and who am I to say otherwise?

DSC_0350Whatever name or category we choose, these are certainly shallow, productive systems (i.e., lots of algae or pondweed growing). That productivity will support a food chain and provide habitat for fish. But too much productivity makes murky water which is less appealing for swimming/boating/other recreation. A common question asked of any limnologist is “how do we reduce the algae/weeds in our pond/lake?” Of course, the answer is “stop fertilizing the pond/lake.” If you don’t want so much plant growth, don’t put silts/sediments, or growth-enhancing chemicals such as nitrogen or phosphorus into the water. Those chemicals increase the productivity of the green photosynthetic organisms—that’s why we consider them “fertilizer.” A nutrient and erosion control strategy is exactly the prescription for Twin Lakes proposed by experts from Iowa State University.

“But Paul,” you say. “Where do wetlands enter in?” Regular readers know that defining, delineating, and characterizing ecosystems are part-and-parcel of the wetland business, more so than other ecosystems. So, we are simply expanding our questions and checklists for “how to define a wetland” to use in ponds/lakes. Fair enough.

Water flows from lands upslope (left) down to South Twin Lake (right)

More importantly, wetlands lie between the land and water. Ecologically, wetlands have characteristics intermediate between terrestrial and aquatic systems. Hydrologically, wetlands often catch runoff, located in a spot where they physically intercept water flowing overland towards a water body (like a lake!). Near the south shore of South Twin Lake, down-slope from farm fields and US highway 20, lies a classic “cattail marsh.” This wetland contains a large area of cattail (Typha) plants, with muskrats (Ondatra zibethicus) and a few willow (Salix) trees. The wetland surely catches runoff heading toward the lake, removing silts and nutrients. Wetlands really do “clean the water,” so visitors to the lakes and lakeshore residents benefit from the work done by the wetlands.

Over the coming weeks, we’ll visit another couple wetlands designed and managed to protect or improve water quality. Let’s think about the challenge of water quality of the specific lake or stream near those wetlands; also keep in mind that the challenge of water quality in Iowa, in particular a form of nitrogen in our waters, is bigger than any particular water body. We have to think bigger, and face some contentious issues. As always, I’ll do my best to explain it all in a straightforward manner…and I’ll have pretty pictures, too! I hope you join me for the journey.

Willows, cattails, and Muskrat. Yup, that’s an Iowa wetland…

Little Sioux, Big Beauty

Ice floes on the Little Sioux

In recent weeks, I’ve been considering engineering and thermodynamics of wetland plants, nest structure design and success, ice safety, and the global carbon cycle. Seems  time to pause and simply enjoy the beauty of wetlands! This past weekend I strolled along the banks of the Little Sioux River at Washta Access in Ida County. I’ve described the dynamics of rivers and floodplains in previous posts, such as the snarled drift at Snarl Street or a Tale of the Swale here in western Iowa. So today, I’m mostly enjoying a nice walk in the woods!

It was a lovely day: sunny and unseasonably warm. There was no wind to speak of, so the woods were quiet. I found myself in a contemplative mood, and lingering here and there, enjoying the colors and textures of the ice and snow and vegetation.

Just upslope from a natural levee, I noted a tree growing straight and true, despite a long, twisting wound along its trunk. Scar tissue bordered the rotting wood, the tree adjusting to this injury and carrying on. Trees contend with such challenges, as they must, but why is this such a perfect, gradual spiral?


Spiral scar on a tree trunk

Trees have such beautiful forms and endless variety! Deciduous (hardwood) trees in winter are especially striking, with the leafless crown revealing the graceful spreading branches, the crevices and coverings on the skin, and the life incorporated on the tree’s body.

It’s easy to think of plants as “dead” in winter, but winter dormancy is more like “hitting the pause button.” A dramatic example is a twining vine caught reaching out into space, frozen (literally) from its journey growing up a little Ash (Fraxinus)  tree sapling. I’d love to come back in 2019 to see what it finally touches. It can stretch out only so far, and then its slender stem will fail to support its own weight…where will it go?

The river nearby has ice encrusted on the banks, and forms a surface on those portions of the channel separated from the current. Crystals grow on top of the ice in elaborate patterns. The black ice and dark water below show them off in high contrast. Floating pieces of ice slid past silently, gracefully. I watched for a few minutes, thinking about those pieces of frozen water heading south. When and where will they melt? I imagine this is all liquid water leaving Iowa, yet the water itself flows inexorably to the sea.

I hope you enjoy the wetlands in winter—the experience is quite different in this season, and a delight…at least when properly dressed, and walking on solid surfaces with good traction  (please be careful!!). Do you have a favorite winter walk? Why not share it in the comments!

Construction Materials from the Marsh

Open water among the ice cover attracted a Bald Eagle, doing a bit of fishing.

Are you interested in how people use plants for food, fuel, medicine, or other purposes? The study of plant use and associated human history and culture is called Ethnobotany, and it’s a topic of interest to me and my students. A previous 99wetlands post featured a few wetland plants eaten by people. And on a recent visit to Otter Creek Marsh Wildlife Management Area in Tama County, I thought again about plant use by humans…and by wildlife, too. In this post, let’s talk about wetland plants as a construction material.

In particular, marshes have a lot of grass-like (graminoid) plants growing up out of the water (i.e., emergent vegetation): examples at a place like Otter Creek often include Cattails (Typha), River bulrush (Bolboschoenus fluviatilis), Softstem Bulrush (Schoenoplectus tabernaemontani), true grasses, and so on.

Think about the challenges those plants face when growing here. Obviously, freezing in winter destroys tissues, so a die-back of everything above the mud is unavoidable. During the growing season, stems must be able to “go with the flow,” bending with the moving water, even including powerful wave action during windy conditions. Yet the photosynthetic stems and leaves must remain upright, out of the water, maximizing sunlight capture. In certain species, those aboveground parts connect to horizontal stems that are spreading through the mud, as well as to the roots. Those tissues in the anoxic (oxygen-free) mud have metabolism of course, and so must have oxygen delivered to them. So the emergent stems and leaves must access oxygen in the air up above, and deliver it down to the belowground tissues.

Frosty Cattail in cross-section; spongy tissue has deteriorated

The leaf structure of Cattail shows solutions to these challenges. Even in winter, the leaves are remarkably sturdy, sticking up out of the ice (and they will persist through the next growing season). The leaves are more-or-less a cylinder down below, presenting less resistance to water movement; yet higher up, they spread out flat to act as efficient “solar panels.” In cross-section the leaf looks a bit like an airplane wing: hollow (saves on materials, and less resistance to wind/water forces) but reinforced with thin internal walls as supports; a spongy material fills in the voids. Even better, that internal structure forms a “snorkel,” allowing air (and oxygen) from from above to diffuse down to the plant parts in the mud.

That system allows cattails to grow, but the story doesn’t end there: those plant tissues prove useful to animals, as well. I saw several Muskrat (Ondatra zibethicus) mounds in the marsh, made of graminoids and Smartweeds (Polygonum) and other plants piled up, incorporating a little mud as a binding agent. The plant tissues are flexible and durable and even somewhat waterproof. They compress a bit, but not too much—great for mounding up. One mound was taller than I am, and formed an igloo-shape. It got me to wondering what it was like inside where the animals were overwintering. For example, does the mounded plant materials keep the muskrats warm??

A large muskrat mound out in the marsh

To help answer that question, and thereby better understand the characteristics of the plant as a building material, I set up a little experiment back at the lab. I compared the temperature in the center of paper cups suspended above a heat source (60W incandescent light bulb). One cup was filled with dried, packed graminoid tissues; one cup contained fiberglass insulation (the material used to insulate the walls and attic of a house), and the Control cup remained empty (well, I suppose it contained air!). I monitored the temperature in each cup using both electronic and glass thermometers, observing the temperature change every couple minutes until it stabilized (about 30 minutes).

Caution: Mad Scientist at work!

I expected a difference in “r-value,” with the fiberglass-filled cup  changing temperature most slowly, the plant cup a bit more quickly, and the empty cup changing temperature most rapidly. I assumed that since each cup was right above an identical (very hot!!) bulb, they would all reach the same elevated temperature soon enough. But…that’s not what happened, actually.

Instead, the temperature changed at about the same rate in each cup—maybe the insulation layer was too thin or the heat-transfer surface too narrow to be important in blocking the temperature change? However, the materials made a BIG difference in the final temperature achieved: the control cup increased temperature by 15 degrees Celsius (59 degrees Fahrenheit), the fiberglass changed 25 C/77 F, and the plant material really heated up—increasing by 32 C/90 F!! It’s been a while since I studied physics, but I suspect this is due to the different thermal mass of the materials. Plant tissues can absorb and store more heat energy than can fiberglass; and air itself has little heat-storage capacity. So, the plant material heats up.

fresh snow reveals tracks of several animals

I wonder what all that means for the muskrats? Being “warm-blooded” animals, I suppose they huddle together down in that mound, sharing body heat. A mass of warm animals in a massive, heat-trapping home makes sense during a cold Iowa winter. They remain active throughout the winter, so their fur must be pretty good insulation, too…no wonder the fur is valuable to humans!

The Meskwaki Settlement is located in Tama County

So, Muskrats find the plants to be a useful building material…but, so do humans! An interpretative display at the marsh describes traditional use of graminoids by the Meskwaki, a nearby settlement of Native Americans/First Peoples. The plants were woven into mats and incorporated into dwellings known as wickiups. We encountered this ethnobotany in a previous 99wetlands visit, to an interpretative nature center in Linn County. I’d love to learn more about traditional uses of plants (and other aspects of history & culture)…if you like, please leave a comment to recommend a reading or a place to visit, etc.

I think it would be fun to visit this site again, perhaps during a warmer season. Maybe I’ll watch the birds with the scope provided at the interpretative display. Till then, I’ll hunker down in my own cozy family dwelling, with an occasional wander out to the marsh. Please come back and read about my further wetland wanderings.

A “bird’s-eye” view for bird-watching?

Battle of the Nest Boxes?

2cansI’ve been known to joke that a useful “wetland indicator” is the presence of wood duck nest boxes. These structures are quite ubiquitous! I’d say the only nest structure more common in wetlands than wood duck boxes, is the classic sawed-off blue-plastic barrel (platform nest for geese, etc.). Anyway, wood duck nest boxes are placed (singly, or multiples) on metal poles in the marsh, or on trees in the forested floodplain. And yes, I’ve seen them in use—they really do work.

So, I was not surprised when I saw several Wood Duck nest boxes at a wetland in Grundy County. I was visiting Holland Marsh which seemed a natural choice for a guy from Pella, an employee of Central College (Go Dutch!). What DID surprise me was the variety in styles of the nest boxes and their placement. A duplex of two different steel canisters sat atop a steel pole along a meander in the floodplain of Holland Creek (photo above). Fun facts I recently learned about such “boxes” include that they were originally developed right here in Iowa, at Union Slough—one of my 99wetlands! Also, the canisters are typically emptied Freon containers…something I’ll ponder next time I use my air conditioning.

Nearby, behind a long angled berm, is a constructed marsh. There I found the other common type of wood duck nest box: an actual wooden box! This one had slipped down its mounting pole, so I could examine and photograph it. A typical example of the style, it was tall, with a wire mesh inside provided to allow a bird (fledgling) to climb up and out when ready to leave the nest.  Although presently in disrepair, a box such as this can be reassembled and used again and again. But please consider the importance of keeping a nest box in good condition. Even a box appearing from the outside to be in perfect condition should be inspected and cleaned at the start of breeding season, and carefully monitored while in use. My observations suggest that too many nest structures (all over, not just in wetlands) are installed with good intentions but not subsequently maintained. An argument could be made that it’s counterproductive—a nest structure prone to predator or parasite problems might be an invitation to disaster for bird parents.

Kevin from the County Conservation Board suggested that perhaps the wood box is more popular with the ducks than the canister type—that seems to be the observations of others as well (see link above). In the battle of the boxes, old-school wood is still best! He also mentioned that routine maintenance of nest boxes is on the To Do list; hopefully that box gets on the schedule. As a cooperative of several conservation organizations (Pheasants Forever, Ducks Unlimited and Iowa Natural Heritage Foundation) work at Holland Marsh will have multiple objectives, in addition to promoting wood duck populations. I was delighted to hear, for example, that Blanding’s Turtles have been noted at the site.

I enjoyed walking around this wetland, enjoying its quiet beauty on a winter’s day. Thin, transparent ice showed the pondweeds beneath, and walking the berm provided a bird’s-eye view of the snaking, meandering Holland Creek. Although overcast, the wind was calm and a raptor soared around me, perhaps enjoying an even better bird’s-eye view. It’s fun to think about all the life still out and about, active all winter long. Perhaps I’ll find more of them…or their tracks, scat, and whatnot…in future wetland wanderings. I hope you’ll join me. Thanks for stopping by!Holland_hawk

On Thin Ice!!

Mud splattered on the snow-covered ice, brought up after I extracted my boot

Have you seen the infographic go around social media, about ice thickness? It features various size objects standing on ice, and how thick that ice must be to support that mass. It’s an amusing reminder to be safe—and it came to mind as I fell though ice this past weekend. (OOOPS!).

At Long Spur Habitat Area (called “Longdpun” in Google Maps???) in Franklin County, I walked out onto the ice of Luke’s Wetland. Despite a stretch of weather with below-freezing temps, the ice was thinner than I had anticipated…this despite having walked around on several ice-covered wetlands previously that day. My foot broke through, and my boot sank in a ways. So, I found myself with two problems: I had insufficient ice thickness, AND my boot had sunk into the mud, and was sucked into the soft muck. My solution was to lean onto the surrounding ice, spreading out my weight; and I made a rocking motion of my foot, allowing water to slip around my boot, breaking the suction of the mud. I took my time, extracting myself safely. But, it’s a good time to remember to be safe outdoors in winter. (Have any tips or anecdotes? Leave a comment!).

The wetland is situated along Spring Creek. The site has a mix of trees and shrubs, and the setting sun made the colors on the buds, stems, and trunks really shine. Let’s have a look with descriptions; you can practice plant identification, something I enjoy (usually!). At the end of the post, I’ll provide my ID for each.

A-this shrub has a profusion of delicate stems, with shiny red epidermis (skin) and opposite leaf/bud arrangement.

B-this tree has clusters of paper-winged seeds, each about 2 inches (5 cm) long; stems were stout with  opposite leaf/bud arrangement.

C-this tree also has opposite leaf/bud arrangement, but upward-curving, thin stems, with shiny red-brown epidermis.

D-this tree has green/gold-skinned stems, tipped with long, sharp buds. The bud and leaf arrangement is alternate (“staggered” on stem). The bark higher up on the trunk is rather smooth and bright.

Across Lark Avenue, a grove of White Pines shelters the birds. I looked for owl pellets (no luck…), but enjoyed seeing many bird prints in the snow (I guess many of you will recognize them? Hint: look closely at the signs to ID the bird!). It was a nice little walk through the trees and along the stream, enjoying the sunset. I hope to return sometime. Thanks for visiting with me!

OK, here are the answers to our little quiz!

A=Redosier Dogwood (Cornus sericea)

B=Green Ash (Fraxinus pennsylvanica)

C=Silver Maple (Acer saccharinum)

D=Eastern Cottonwood (Populus deltoides)

And those bird tracks belong to the Ring-necked Pheasant, Phasianus colchicus.